Final draft of a working paper prepared for the Secretariat
of the Commission for Environmental Cooperation

This working paper was prepared by:

Horsley & Witten, Inc.
Sextant Hill, Unit 1
90 Route 6A
Sandwich, Massachusetts 02563
USA
Telephone: (508) 833-6600

This working paper was prepared for the Secretariat of the Commission for Environmental Cooperation (CEC). The views contained herein do not necessarily reflect the views of the CEC, or the governments of Canada, Mexico or the United States of America.

Reproduction of this document in whole or in part and in any form for educational or non-profit purposes may be made without special permission from the CEC Secretariat, provided acknowledgment of the source is made. The CEC would appreciate receiving a copy of any publication or material that uses this document as a source.

© Commission for Environmental Cooperation, 1998

For more information about this or other publications from the CEC, contact:

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In North America, we share vital natural resources including air, oceans and rivers, mountains and forests. Together, these natural resources are the basis of a rich network of ecosystems which sustain our livelihoods and well-being. If they are to continue being a source of future life and prosperity, these resources must be protected. Protecting the North American environment is a responsibility shared by Canada, Mexico and the United States.

The Commission for Environmental Cooperation (CEC) is an international organization whose members include Canada, Mexico and the United States. The CEC was created under the North American Agreement on Environmental Cooperation (NAAEC) to address regional environmental concerns, help prevent potential trade and environmental conflicts and to promote the effective enforcement of environmental law. The Agreement complements the environmental provisions established in the North American Free Trade Agreement (NAFTA).

The CEC accomplishes its work through the combined efforts of its three principal components: the Council, the Secretariat and the Joint Public Advisory Committee (JPAC). The Council is the governing body of the CEC and is composed of the highest-level environmental authorities from each of the three countries. The Secretariat implements the annual work program and provides administrative, technical and operational support to the Council. The Joint Public Advisory Committee is composed of fifteen citizens, five from each of the three countries, and advises the Council on any matter within the scope of the agreement.

The CEC facilitates cooperation and public participation to foster conservation, protection and enhancement of the North American environment for the benefit of present and future generations, in the context of increasing economic, trade and social links among Canada, Mexico and the United States.

A healthy marine and coastal environment in the Gulf of Maine where human use and biological diversity thrive in harmony.

The GPAC will work with all interested parties to assist in the application of the Global Programme of Action for the Protection of the Marine Environment from Land Based Activities (GPA). This Coalition will draw from and build upon the existing work of the Gulf of Maine Council, the Regional Association for Research in the Gulf of Maine, the Commission for Environmental Cooperation (CEC) and other organizations and individuals committed to the protection of this shared public resource of world-class cultural, economic, ecological and intrinsic value.

The GPAC will assist public and private entities in the Gulf of Maine region identify pollution and habitat priorities and work to strengthen the capacity of these organizations and individuals to address them.

Identify and assess current knowledge on the marine and coastal habitats of the Gulf of Maine and the existing and potential effects of pollutants from land based activities on their sustainability.

Organize a workshop of multi-disciplinary and cross-sectoral participants to review this knowledge and produce a consensus list of the priority pollutants and critical habitats in the Gulf of Maine requiring immediate action.

Identify strategies and measures related to the management of priority pollutants and critical habitats identified during this first workshop.

Organize a second workshop of multi-disciplinary and cross-sectoral participants to assess management strategies and produce a regional response with immediate and long-term measures intended to reduce pollutants and protect and manage habitat in the Gulf of Maine. It will include financing mechanisms and a process for review and evaluation of implementation success.

Secure resources from interested stakeholders to begin implementation of actions to advance the elements of the Action Plan.

 

Broad-based, cross-sectoral stakeholder consensus on regional habitat and pollutant priorities and commitment to responding to them.

Implementation begins, within and across jurisdictions, including select demonstration projects.

Transitional seed financial support from the CEC for implementation.

Strengthened bi-national commitment to GPA implementation.

Conclusion of GPAC role as regional stakeholders initiate implementation.

 

The Global Programme of Action for the Protection of the Marine Environment from Land-Based Activities, usually abbreviated to the Global Programme of Action or simply the GPA, was developed and adopted by the United Nations Environment Programme on 3 November 1995. The GPA calls for actions by each signatory nation to preserve and protect the marine environment on a national, regional and international basis in order to reach the goal of "sustainable seas." The GPA goes into detail on recommended approaches for nine different source categories such as sewage, heavy metals and physical alterations.

In North America, the Commission for Environmental Cooperation (CEC) was created as a result of the North American Free Trade Agreement (NAFTA) negotiations to facilitate cooperation and public participation to foster conservation, protection, and enhancement of the North American environment. In pursuing its mandate, the CEC decided to promote a series of pilot projects in North America to implement the GPA, and selected the Gulf of Maine (GOM) as a candidate site for one of the projects. The CEC brought together a diverse group of individuals with an interest in the GOM and the GPA to develop and implement a project of their own design, with some support from the CEC. The group, which has named itself the GPA Coalition for the Gulf of Maine (GPAC), has formulated an action plan to this end. A key component in the plan is a workshop in Saint John, New Brunswick on 27 and 28 April 1998 at which participants will focus on impacts due to contaminants in the GOM and develop a consensus list of priority contaminants upon which an action plan to reduce or eliminate their impacts would be developed. The participants will include industry, community groups, municipalities, scientific institutions, First Nation/Tribal groups, provincial governments and the federal government. In order to focus that workshop on the priority contaminants, a scoping paper is needed for consideration by the participants prior to the workshop.

A task group was established through the GPAC to provide advice to the Consultant and to review progress and final reports.

Chair:

The Gulf of Maine is located off the northeastern coast of the United States and Canada. Its watershed encompasses 69,115 square miles in three U.S. states and three Canadian provinces: Massachusetts, New Hampshire, Maine, Nova Scotia, New Brunswick and a small portion of Quebec (Conkling 1995).

Figures from Richard Kelly, Jr., Maine State Planning Office (in Conkling 1995)

The overall watershed may be sub-divided into 25 major watersheds (13 in the United States and 12 in Canada) and 11 minor coastal drainage areas (Pait 1994). Major river drainages in the watershed include the Merrimack, Saco, Androscoggin, Kennebec, Penobscot, St. Croix and Saint John rivers (Conkling 1995).

Figures from S. Meyer, Island Institute (in Conkling 1995).

According to NOAA’s National Estuarine Inventory Data Base, there are 13 estuaries and one sub-estuary within the U.S. portion of the Gulf of Maine. Land-use data from U.S. watersheds adjacent to estuaries (circa 1975) show the significant amount of undeveloped land at that time. Nevertheless, the U.S. portion of the Gulf’s watershed is the third most densely populated coastal region in the country (Gottholm and Turgeon 1992). The 1990 population for the Gulf of Maine watershed was 6.8 million with Boston and Saint John as the two largest metropolitan areas.

(NOAA 1987 in Gottholm and Turgeon 1992)

 

The principal goal of this scoping paper is to provide a background on the state of knowledge regarding contaminants and their impacts in the Gulf of Maine, and to offer a basis for further action by the GPAC. Specifically, the topic of contaminants and their impacts will be discussed at a Workshop in Saint John, New Brunswick, Canada scheduled for 28–29 April 1998. At this Workshop, the GPAC intends to establish a series of priorities for future actions.

The Global Programme of Action for the Protection of the Marine Environment from Land-Based Activities (GPA) categorizes contaminants as the following (not listed in order of priority):

sewage;
persistent organic pollutants;
radioactive substances;
heavy metals;
oils (hydrocarbons);
nutrients;
sediment mobilization; and
litter.

In this document, we have chosen a slightly different format. Because the categories of sewage and sediment mobilization refer not to contaminants per se, but to sources or means of distribution of contaminants, we will not utilize them directly. Sewage and sediments as sources, sinks, or temporary repositories for contaminants will be incorporated into the discussions of virtually all of the contaminants. To the listing of contaminants, we have added pathogens; bacteria and viruses. The report does not include discussions of radioactive substances or litter, not because they are unimportant generally or in the Gulf of Maine in particular. In this case, limitations on time and budget precluded their inclusion.

The GPA includes litter and radioactive substances in its list of contaminants but GPAC has excluded them from further consideration at this time, in order to focus its limited resources and time for this initial effort. In the initial report by VanderZwaag and Pederson (1997) that started the GPAC process, radioactive substances were given a low priority. We recognized that there probably are very good local area data on radioactive substances but anticipated that broad regional data would be poor.

Litter, especially plastics, is essentially a physical issue—an aesthetic problem from the human perspective and a cause of mortality by entanglement or ingestion for marine creatures. The Gulf of Maine Council on the Marine Environment and other groups have undertaken a number of initiatives to educate people to prevent the disposal of plastics and other litter into the water, and to clean beaches of what does get deposited.

This report deals with a limited number of a very large group of potential pollutants. The process of identifying priority pollutants is evolving, and future work may well consider radioactive substances, litter or other pollutants.

Consequently, the organization of this paper will be as follows:

1. pathogens

a) bacteria

b) viruses

2. persistent organic pollution

a) pesticides

b) PCBs

c) dioxins/furans

3. heavy metals

a) arsenic

b) cadmium

c) chromium

d) copper

e) lead

f) mercury

g) tin

h) zinc

4. oils (hydrocarbons)

a) PAHs

b) oil spills

5. nutrients

a) nitrogen-based compounds

b) phosphorus

As much as possible, we have organized the information around the following attributes of each contaminant:

contaminant name,

trends in presence and impacts, including temporal and spatial distribution and concentration,

human health impacts,

ecosystem impacts,

economic impacts,

cultural impacts,

information base, including:

land-based source(s) of the contaminant

quantity of the contaminant released from the source(s),

pathways traveled to reach the Gulf of Maine and changes that occur during transport, and

gaps in information or data.

Unfortunately, as will be clear in the following text, in many instances either the information is not available or we were not able to locate it in the time allotted for this project.

We began the data collection process by contacting the members of the Contaminant Task Force for their suggestions as to the most significant researchers and summary papers available relating to contaminants and their impacts in the Gulf of Maine. We followed by contacting those researchers as well as the appropriate state and federal agencies working in the field. A listing of the papers reviewed may be found in the Bibliography and References.

An assessment of impacts from contamination within the Gulf of Maine must, of necessity, come from a review of a sizable number of data sets. Few of these were developed with the goal of assessing the Gulf of Maine in its entirety; rather they were collected, analyzed and reported for a wide range of purposes. In the limited time allotted to the preparation of this summary, the authors have attempted to identify the most comprehensive, incorporating more focused data sets as appropriate. The types of information reviewed included the results of state coastal monitoring programs, an inventory of point source loads, basic research on biological contaminants and their effects, and summary papers of research done in the Gulf of Maine.

Three aspects in particular were of interest:

sources of contaminants

Point source information was summarized in a 1991 inventory of point source loading prepared for the Gulf of Maine Council on the Marine Environment. This inventory was based on data from 1990 and earlier and was primarily taken from permitting information. Compliance is based on self-monitoring by permittees.

A review of nonpoint source inputs into the Gulf is currently underway, but was not available for the purposes of this paper.

contaminants in the Gulf

The most comprehensive set of data available on this topic is a contaminated sediments database under development by the U.S. Geological Survey (USGS). This summarizes data from the past 25 years, but unfortunately only covers the U.S. portion of the Gulf. Their preliminary data displays may be found on their Gulf of Maine web site at http://oracle.er.usgs.gov/GoMaine/data.html (or go directly to examples of sediment maps at http://oracle.er.usgs.gov/consed/). We were not able to locate a broad survey of similar data for the Canadian portion of the Gulf and the Bay of Fundy.

A number of more localized surveys of sediment contamination levels are available which serve to illustrate particular situations, many of which have been incorporated into the USGS summary.

contaminant uptake into biota

The Gulfwatch program was established in the early 1990s to measure uptake of various contaminants by utilizing blue mussels (Mytulis edulis)as indicators of exposure. In 1996, 18 sites were monitored; 3 in Massachusetts waters, 1 in New Hampshire, 6 in Maine, 3 in New Brunswick, and 5 in Nova Scotia.

A number of other studies have measured particular contaminants, or groups of contaminants in various species of animals. None of these were (or were intended to be) Gulf-wide surveys but they provide additional information about the movement of contaminants into the food web, and ultimately to human consumers.

These 1991 point source inventory, the USGS contaminated sediments database and Gulfwatch are the most complete surveys of conditions within the Gulf of Maine. They will be referred to with regularity throughout this paper.

In the process of mitigating the impacts of contamination, perhaps as important as understanding what contaminants are present is understanding how they got there. There are a number of transport mechanisms operating in the Gulf of Maine region including point source discharges and non-point sources from surface run-off, groundwater and riverine discharges as well as atmospheric deposition. The only available comprehensive summary related to transport mechanisms is the previously-mentioned point source inventory. An assessment of atmospheric deposition was conducted in 1995 by MacAdie for the International Joint Commission which identified several data gaps that require further study before an adequate evaluation can be made for many of the contaminants of concern. The assessment did provide estimates of atmospheric deposition for certain metals (e.g., atmospheric deposition accounts for 25 percent of the total lead and 15 of the total cadmium loadings to the Gulf).

Approximately 300 billion gallons of effluent from at least 378 wastewater treatment plants are discharged annually into the Gulf of Maine or waterbodies which drain directly to the Gulf (Pait 1994). This discharge contains a range of contaminants, depending on the level of treatment at the wastewater facility or pretreatment at industrial or commercial facilities connected to the sewer lines.

(Summarized from Pait 1994)

The contaminants in wastewater may include pathogens, bacteria or viruses. Most of the wastewater treatment plants on the Gulf, at a minimum, disinfect effluent or solids discharged. Pederson and VanderZwaag (1997 citing Conkling 1995) note one significant exception as Saint John, New Brunswick, from which 23,365 m³ per day (1.25 billion gallons per year) are discharged with no treatment.

Only a very limited number of facilities treat sewage for the removal of nutrients. Consequently, wastewater discharges can introduce significant amounts of these materials into Gulf waters.

Depending on connections to industrial or commercial facilities, levels and types of pretreatment, or connections to stormdrains, wastewater treatment facilities may provide point sources for the discharge for a wide range of toxic materials.

Fecal Coliform, as an indicator of pathogenic bacteria.

Fecal coliform bacteria live in the intestines of warm-blooded animals. Consequently, their presence provides an indicator of fecal contamination. The amount of these bacteria measured in the environment is utilized by managers as a threshold to determine whether harvesting of shellfish or water-contact recreation should be prohibited in order to avoid public health concerns.

Gulf-wide, measurable fecal coliform levels are found in estuaries and nearshore waters. Concentrations tend to be higher at low tide than at high, largely as a function of greater dilution and better mixing in the latter situation. There are some indications that there are also seasonal variations in fecal coliform levels, but these appear to be more related to seasonality in run-off rather than to sewage discharge (Jones in press). Higher bacteria levels are also generally associated with larger population centers.

Many of the most productive clam beds and mussel harvesting areas in the Bay of Fundy are closed to harvesting because of sewage contamination or as a precaution against wastewater treatment facility failure (Conkling 1995). A number of communities in that region dump untreated, or minimally treated, sewage directly into the sea, or into the rivers and estuaries that flow into it. For example, prior to 1994, the City of Moncton, New Brunswick, discharged over 100,000 cubic meters (~.25 million gallons) per day of untreated sewage into the Petitcodiac River Estuary at the head of the Bay. By 1995, the effluent was treated to remove solids, but this did little to reduce the input of organic matter, toxic chemicals and noxious bacteria (Conkling 1995). As mentioned above, a significant volume of the sewage from Saint John, New Brunswick, is dumped untreated into the harbor (CARP 1996a).

In the 1980s, the North Atlantic region of the U.S. (Maine, New Hampshire and Massachusetts) experienced the greatest nationwide increase in percentage of estuarine shellfish growing waters closed for harvesting: from 12 percent in 1985 to 31 percent in 1990. During that period, eight of the 15 estuaries in the region were downgraded in their classification of shellfish growing waters (more acreage closed to shellfishing), while five were upgraded (had shellfish beds re-opened). Efforts to improve water quality by municipalities and state/provincial agencies in the Gulf have produced some "re-openings" since 1990 (Pederson & VanderZwaag 1997).

(in thousands of acres)

(NOAA 1997b)

Total classified acreage in Maine, New Hampshire and Massachusetts increased by over one million acres between the 1990 Register and the 1995 version; 80 percent of this new acreage is located in non-estuarine waters. Approved waters decreased from 84 percent in 1990 to 80 percent in 1995. While all three North Atlantic states reported increases in the total amount of shellfish bed acreage, the biggest change occurred in Massachusetts, where classified non-estuarine acreage almost tripled.

The top three pollution sources identified as affecting harvest limitation in estuarine and non-estuarine waters are wastewater treatment plants, direct discharges and urban run-off. Jones (in press) reports that fecal bacterial concentrations have decreased in New Hampshire coastal waters since the 1990s as a result of improvements to wastewater treatment facilities, but that they were higher in 1995–6 than previous years, perhaps due to increased rainfall during that period.

The closure of shellfish beds to harvesting or beaches to water-contact activities appears to be a reasonably effective means of protecting public health; there have been only limited numbers of reports of human health-related problems from fecal bacteria.

A recent epidemiological study in Santa Monica Bay, California, provides a strong suggestion that run-off through storm drains (with suspected illegal connections to septic sources) can be linked to human health impacts. People who swam in front of flowing storm drains were 50 percent more likely to develop symptoms than those who remained 400 yards away from the drains. The "closer" group of swimmers experienced a broad range of adverse health effects including fever, nausea and gastroenteritis, as well as cold and flu-like symptoms. Increased health risks were associated with high bacterial indicator counts, although it was not clear what the causative agent(s) was for the symptoms (Haile et al. 1996).

We were unable to find any quantifiable measures of impacts to the Gulf of Maine ecosystem from pathogenic bacteria. Apparently, little has been published about whether or how bacterial diseases are spread from humans to other segments of the marine ecosystem, particularly in this region.

Shellfish closures, while effective in protecting public health, have direct economic impacts to coastal communities and their citizens through the loss of shellfisheries and restrictions of recreational uses. For example, losses to the coastal economy in Massachusetts from bacterial contamination of shellfish and recreational waters exceed $75 million annually (Weiskel et al. 1996).

In addition to economic impacts, shellfish closures due to potential bacterial contamination also have cultural impacts. Loss of full-time or part-time jobs disrupt traditional ways of life in smaller communities as well as First Nation/Tribal groups. In some First Nation/Tribal groups, hunting and gathering traditions are still important from both a cultural and economic basis. The inability to harvest shellfish curtails a traditional activity and removes a traditional foodstuff from the community (Leighton 1998, pers. comm.).

Tribal and First Nation groups feel disenfranchised in cross-boundary issues related to wastewater treatment plant discharges and other pollution issues. The International Joint Commission (IJC) has no tribal representation and a staff member from the Passamaquoddy Tribe at Pleasant Point, Maine, expressed that they felt that they had no input on sewage issues in the St. Croix River/Passamaquoddy Bay complex (Leighton 1998, pers. comm.).

In urban areas, stormwater run-off and wastewater treatment plants are the primary source of fecal coliform bacteria and related pathogens. This may vary, depending on the level of technology utilized by the wastewater treatment plant, the sewer system design (particularly as related to combined sewer overflows) and frequency of plant failure. In more rural areas, the primary sources may stem from waterfowl or other wildlife, pets and run-off of manure from agricultural sites.

Point source data from 1991 identified the South Essex (MA) WWTP as the largest contributor of fecal coliform bacteria in the Gulf of Maine. The second largest source was identified as the Moncton (NB) Sewerage Commission and the third was the Yarmouth (NS) sewage treatment plant (Pait 1994).

A modeling study of fecal loads done for the Casco Bay Estuary Project cites the two principal sources of fecal coliform bacteria impacting Maquoit Bay as agriculture and residential land use (in order of relative importance). Fecal coliform loading via streams and shoreline seeps appears to be responsible for the long-term shellfishing closures there (Horsley & Witten 1996).

Although the total volume of effluent from wastewater treatment plants into the Gulf of Maine and its watershed can be measured to a fair degree of accuracy and the levels of fecal coliform bacteria can show locations of potential concern, very little has been reported about the amount and types of pathogenic bacteria reaching the waters of the Gulf. At the time of this writing, there is little in the way of comprehensive data available for nonpoint source inputs.

Bacteria travel to the Gulf of Maine from both point and non-point sources. Those associated with human sources are discharged into the marine environment primarily when sewage systems, either on-site or wastewater treatment facilities, are not functioning properly. Generally, bacterial loadings are associated with highly populated areas, particularly those that have limited facilities to deal with wastes. A second primary vehicle for fecal coliform transport to receiving waters is stormwater run-off (Horsley & Witten 1996).

Fecal coliform bacteria can survive in saltwater for up to 30 days, and possibly longer. In addition, they may become entrained in sediments and along the wrack line and be re-released into the environment long after their original introduction (Weiskel et al. 1996).

Currently there is a general lack of information regarding non-point source loading to the Gulf of Maine. The non-point source model presently under development does not have a fecal coliform component and it is unclear whether or not such an element can be incorporated. It is possible that pathogens, reflected by fecal coliform contamination, are affecting the Gulf of Maine on a broad scale basis, but there has been no comprehensive study to demonstrate this or ascertain the extent of the problem. Most reported impacts are human health-related, i.e., illness due to ingestion of shellfish exposed to sewage or swimming in waters contaminated by run-off or discharge. The effects of these contaminants on wildlife species was not reported in the papers we reviewed.

An additional question related to pathogens is whether coliform bacteria are an accurate indicator of pathogen inputs or their presence.

Pathogenic viruses

The movement and impacts of viruses in the coastal and marine waters of the Gulf have received limited attention. However, their ability to move through the system and survive for significant periods suggests that this is an area suitable for further investigation.

Viruses tend to be between one and two orders of magnitude smaller than bacteria and consequently are generally not filtered out as septic effluent percolates through the soil, with the exception of movement through soils with high clay content. The most significant factor in determining viral survival (or inactivation) in groundwater is temperature. In coastal Maine the groundwater temperature is approximately 7–8 degrees Celsius year-round. At this temperature, viruses can be expected to survive for periods of 800–1,000 days (Horsley & Witten 1996). If groundwater moves on the order of one foot per day, septic systems within a 1000–foot distance from the shore could be expected to contribute some level of viral contaminant load.

Persistent organic pollutants (POPs) include a wide array of chlorinated compounds, among which are polychlorinated dibenzodioxins, polychlorinated dibenzofurans and polychlorinated biphenyls (PCBs). These compounds do not readily degrade in the environment and tend to bioaccumulate in mammals. Pesticides have been widely used on agricultural and forested lands in the Gulf of Maine watersheds and thus enter the marine system through nonpoint sources such as run-off and atmospheric deposition. The characteristics that made these synthetic chemicals useful, their toxicity to pest species, also makes them toxic to other, non-target organisms. Unfortunately, when these chemicals were being spread widely, little was known about their adverse effects and resistance to degradation.

Due to the nature of these compounds, their persistence in the environment, and their mobility, it is difficult to accurately estimate the total amount that reaches the Gulf of Maine and for what period it remains there.

Many animals show reproductive problems that have been linked to POPs, but marine mammals such as whales, dolphins, seals and polar bears may face the greatest jeopardy, particularly over the long term. Persistent chemicals accumulate and concentrate greatly in the marine food web, potentially exposing the long-lived predators to high levels of contamination. These chemicals are passed to offspring through breast milk (Colborn et al. 1997).

Recent research suggests that exposure to persistent organic pollutants may pose significant risk to a much larger proportion of the general human and wildlife population than previously thought. Some POPs are now known to act as endocrine disrupters mimicking the body’s hormones, turning off and on important developmental processes at critical times. Some scientists believe that fetal exposure to endocrine disrupters or estrogenic chemicals (including some organochlorines such as DDT, some PCBs, dioxins and furans) may be responsible for declining sperm counts and the rising incidence of abnormalities in human male reproductive tracts (CEC 1997b).

A recent study of organic chlorine contamination in porpoises from the coast of Newfoundland, the Bay of Fundy and the Gulf of St. Lawrence (Westgate et al. 1997) indicates that PCBs and chlorinated bornanes (historically referred to as toxaphene and polychlorinated camphenes) were the dominant contaminants in all porpoises. Results indicate that there have been significant declines in both PCBs and DDT in Bay of Fundy Harbor porpoises since the 1970s. Addison et al. (1984 in Westgate et al. 1997) documented declines in PCBs and DDTs in east coast gray and harp seals between the early 1970s and early 1980s. PCB and 4,4’-DDE levels in harbor seals from the Gulf of Maine have also been reported to have declined between 1980 and 1990–1992 (Lake et al. 1995 in Westgate et al. 1997). The report speculates that the magnitude in the decline recorded in harbor porpoises could reflect the fact that the spraying that previously took place in the forests surrounding the Bay of Fundy (some of the heaviest in North America (Addison 1984 in Westgate et al. 1997)) has been largely curtailed.

For some First Nation/Tribal groups, bioaccumulation in marine mammals can be a significant issue for human health. A report from a representative of the Passamaquoddy Tribe (Leighton 1998, pers. comm.) at Pleasant Point, Maine, notes that porpoise remains a traditional food source. Tribal members take approximately 50 porpoises a year for traditional meals. Of particular concern is that tribal members consume virtually all of the animal, not merely the muscle tissue, with the liver being a particular delicacy. A similar situation occurs with the consumption of fish. Tribal members typically consume the entire fish, not only the fillets of muscle tissue. Most fish sampling done by government health officials, however, focuses on fillets, not the entire body burden of contaminants. This, combined with a strong tradition of use of marine species, suggests that Tribal/First Nation members may be consuming a greater load of contaminants than the general population.

Chlorinated pesticides (DDT, lindane, dieldrin, aldrin, chlordane, toxaphene, heptachlor, DDD and DDE),

Organophosphorus pesticides (parathion, malathion, systox, chlorthion, disyston, dicapthon and metasystox).

 

Chlorinated pesticides have been used widely as insecticides, fungicides and herbicides in agricultural and forestry activities in the region of the Gulf of Maine.

A survey by NOAA on pesticide use in Maine, New Hampshire and Massachusetts indicates that the major harvested crops include hay, corn, alfalfa and blueberries. Over 254,000 pounds of the inventoried pesticides were applied for agricultural purposes in areas draining to the region’s estuaries in 1987. This is lower than other regions of the U.S., in large part because these three states have the lowest (7 percent) amount of agricultural land use within their estuarine drainage basins. The major crop-growing estuarine drainage areas in the three states are Sheepscot Bay, Penobscot Bay and the Merrimack River. Within the three states, the Sheepscot Bay estuary had the highest pesticide use. Penobscot Bay, Muscongus Bay and Great Bay were cited as having the "highest hazard normal application" of pesticides for the region. The hazard normal rating system was developed to rank the inventoried pesticides in their potential to impact estuarine organisms (primarily fish and crustaceans), and to rate the estuarine systems in the application of the more hazardous pesticides in NOAA’s inventory (Pait et al. 1992).

Of the herbicides inventoried, Atrazine was the most heavily applied in the Maine, New Hampshire, Massachusetts region. Metriam is the most commonly used of the fungicides (Pait et al. 1992).

More than 5 million kg of DDT were sprayed on forests in New Brunswick and Quebec between the early 1950s and the late 1960s (Nigam 1975 cited in Noble 1990). Large tracts of forest in New Brunswick were sprayed with DDT to combat spruce budworm infestations and the insecticide and its residues entered the Bay of Fundy as run-off from the Saint John River. Every 4 years between 1972 and 1988, the eggs of four seabird species were sampled for organochlorine contamination. The species were the Double-crested Cormorants from Manawagonish Island at the mouth of the Saint John River, Leach’s Storm-Petrels from Kent Island, Atlantic Puffins from Machias Seal Island and Herring Gulls from all three areas. In all four species residues of DDE and PCBs declined significantly (Noble 1990) as did dieldrin in the eggs of puffins and commorant. The decline in DDT was attributed to the cessation of forest spraying. Declines in PCBs suggested that local pollution, since ceased, had been contributing in the past. Other organochlorine compounds such as HCB, HCH, oxychlordane and heptachlor epoxide levels were variable, but just as high in 1990 as they were in the mid-1970s (Noble 1990).

DDT and chlorinated pesticides are highly resistant to degradation in the marine environment and may accumulate to high concentrations in both sediments and biota but relatively few data exist for the Gulf of Maine. The livers of winter flounder from Boston and Salem (Massachusetts) Harbors contain some of the highest concentrations of DDT found on the east coast of the U.S. (Larsen 1992 based on data from NOAA Status and Trends 1987) and are ranked first and third respectively in the country in terms of total chlorinated pesticides. Lipophilic organic contaminants were found in fish liver samples from Boston Harbor and Quincy Bay including high concentrations of DDT, other chlorinated hydrocarbons and total PCBs (Gottholm and Turgeon 1992).

Concentrations of individual pesticides in sediments from the Kennebec River Plume are as high or higher than in sediments from urban harbors such as Boston.

In the few areas of the U.S. coastline for which long-term data sets exist, the concentrations of chlorinated hydrocarbons in sediments and tissues of marine organisms appear to have been declining since the late 1960s and early 1970s (Mearns et al. 1988 in Capuzzo 1995). Larsen (1992) reported substantially lower DDT concentrations in porpoises in the Bay of Fundy region than what was measured in the 1970s. Similar declines in body burdens of DDT were noted in east coast gray and harp seals between the early 1970s and early 1980s. Levels of 4,4’-DDE in harbor seals from the Gulf of Maine have also been reported to have declined between 1980 and 1990–1992 (Lake et al. 1995 in Westgate et al. 1997).

Lindane (used as an insecticide) concentrations in atmospheric deposition samples in Nova Scotia indicate a pattern of diminishing concentrations from 1980 to 1988 (Environment Canada 1992).

(CEC 1997a)

Winter flounder collected near Lynn, Massachusetts, contained heptachlor in amounts close to the US Food and Drug Administration limit for humans, and also contained elevated levels of DDT (Connolly 1991 in Langton et al. 1994).

None of the organochlorine contaminants detected from monitoring efforts in the eggs and tissues of Canadian seabirds reported by Noble (1990) were at levels high enough to kill birds that had fledged. However, there were adverse effects on reproduction in some Canadian seabirds. During the early 1970s, 20 percent of the Double-crested Cormorant eggs laid in eastern Canada contained more than 15 mg/kg DDE, theoretically enough to cause a 20 percent reduction in eggshell thickness in these species. No information is available on the reproductive success in those colonies. Small amounts of eggshell thinning probably occurred in a number of other species, including Leach’s Storm-Petrels from the Bay of Fundy, in the early 1970s (Noble 1990).

Pesticides have been implicated in abnormal gastrulation and a high incidence (39 percent) of vertebral deformities in developing eggs from winter flounder experimentally exposed to very low (sub-lethal) doses of DDT (1-2 ppb) (Smith and Cole 1973 in Langton et al. 1994). Similar experiments with dieldrin did not elicit the same response. Chlordane in high doses induced severe liver damage in laboratory experiments with winter flounder (Langton et al. 1994).

In our review of articles related to pesticides, we did not note any data on economic impacts. However, it is possible that the use of pesticides may have had an impact on fisheries by affecting the ability or juvenile stages to reach reproductive age or to successfully reproduce—thereby having population impacts. This may have had some level of impact on fisheries resources.

The limited information we were able to gather on First Nation/Tribal use of fisheries was insufficient to ascertain whether increased body burdens of pesticides in fish or marine mammals has had any cultural impacts.

Most of the chlorinated and organophosphorus pesticide residues in the Gulf of Maine ecosystem appear to have come from agricultural and forestry practices. Data summarized by Hauge (1988 in Larsen 1992) suggest that agricultural run-off may contribute large inputs of chlorinated pesticides, such as aldrin, chlordane and heptachlor to the Gulf of Maine through the Kennebec estuary.

Although the use of DDT has been banned in the U.S. and Canada for many years, some amounts may make their way into the Gulf via long-range atmospheric transport from countries that still produce and utilize this pesticide. Because DDT persists in soils for long periods of time, other current inputs may enter the Bay of Fundy and other portions of the Gulf in run-off from basins that were "contaminated" many years ago (Westgate et al. 1997).

Virtually no information was located regarding the amounts of pesticides reaching the waters of the Gulf of Maine, either overall or as specific types.

Pesticides were originally sprayed over land areas. While some may have been sprayed accidentally over water, most entered aquatic systems adsorbed onto fine-grained materials. These could either travel via air or water to coastal waters. Once in the marine system, they typically become part of the sediments to be resuspended or taken up by benthic organisms.

Few data are available on the impacts at the population level from pesticides, particularly on economically-important species. The comparative inputs from contemporary sources such as nonpoint run-off, atmospheric deposition or mobilization of contaminated sediments are poorly defined.

Polychlorinated biphenyls (PCBs)

Polychlorinated biphenyls (PCBs) contain a mixture of biphenyls with chlorine atoms attached at any of the carbons resulting in at least 210 possible PCB compounds, or arochlors. In 1979, the US EPA banned their manufacture, processing and distribution (LaGrega, Buckingham, Evans 1994 in Conkling 1995). Similarly, the sale, manufacture and import of PCBs is prohibited in Canada (CEC 1997b).

The principal use of PCBs was as insulating material in electrical transformers and capacitors. "Escape" into the environment occurred during manufacturing activities and as electronic components broke down. PCBs were also utilized in many other dispersive ways, including such things as carbonless copy paper. They are very persistent in the environment, do not dissolve readily in water and easily adsorb onto fine grained particles--all traits which make their movement through the watershed into the marine ecosystem possible and extend the potential for exposure for both humans and wildlife. Because of their affinity for fine-grained particles, PCBs are also available for atmospheric deposition.

Surveys in 1982 and 1983 found trace amounts of PCBs in sediments in Penobscot Bay and in the deep offshore basins of the Gulf (Larsen et al. 1986) but, in general, only limited data exist for PCB levels in sediments (Mearns et al 1988 in Capuzzo 1995).

Observations in Nova Scotia of concentrations of PCBs in precipitation show a decrease to non-detectable levels in mid-1983 (Environment Canada 1992). Since 1985 only a few observation of PCBs in precipitation have been made (Environment Canada 1992).

After the manufacture of PCBs was banned in the 1970s, there was a marked decrease in inputs. However, global-scale recycling of PCBs between the atmosphere and land and ocean surfaces is probably reaching an equilibrium and the rapid improvements seen in the 1970s will probably not continue (Norstrom 1988). Trends in PCB concentrations within the Gulf of Maine ecosystem appear to be mixed. Larsen et al (1984b) found increases in Casco Bay sediments in the early 1980s. Nordstrom (1988) noted declines in body tissues of petrels from the North Atlantic between 1968 and 1984. There are indications that there have been significant declines in the body burdens of marine mammals of the Gulf since the 1970s as reported in harbor porpoises, gray and harp seals (Addison et al. 1984 in Westgate et al. 1997), and harbor seals (Lake et al 1995 in Westgate et al. 1997).

A recent study of lobster digestive glands (King et al. 1996 in Chase 1997) from specimens taken from four maritime harbors of Atlantic Canada showed PCB-derived toxic equivalent concentrations exceeding the Canadian toxic level of 20 pg/g. This same study noted that the dioxin tolerance was exceeded by factors of 1–10 times while total PCB concentrations of the same samples did not exceed the Canadian PCB tolerance concentration of 2 ug/g wet weight.

In a survey of trace contaminants in fish livers, the NOAA National Status and Trends Benthic Surveillance program for the years 1984–1987 found high concentrations of total PCBs in Boston Harbor and Quincy Bay (Gottholm and Turgeon 1992).

PCBs were the most prominent organic contaminants in porpoises from the Bay of Fundy region (Westgate et al. 1997) but the data do not indicate where or when the contaminants were acquired.

Gulfwatch data in 1995 indicate, as in previous years, that within the Gulf there is a general trend toward higher PCB concentrations in mussels as one moves southwards (Chase 1996).

(Compiled from data in Chase et al. 1997

(CEC 1997a)

The effects on people who consume fish or shellfish with these contaminants is largely undefined, but there are suggestions that at least some forms of PCBs may be carcinogenic or disrupt reproductive functions (Gulf of Maine Council 1994). Despite the lack of certainty, there has been sufficient concern that fishery advisories have been established based on elevated PCB levels. For example, two advisories have been issued by the State of New Hampshire related to fish consumption, both based on elevated PCB levels. One is directed at tomalley of lobsters taken from the Great Bay estuary. The other was issued in 1987 and pertained to bluefish (NOAA 1987 in Jones in press).

Toxic effects of PCBs in marine life include liver damage, tumors, a wasting syndrome, neurotoxicity, reproductive failure, immunotoxicity, birth defects and death (Eisler 1986). The response to PCBs depends on the specific form or mixture and the age, sex and species of the exposed animal. Most of the effects appear to be from chronic exposure, toxicological thresholds are generally high. Some species of fish, particularly those which migrate over large distances (e.g., bluefish, striped bass and coho salmon), have been found to have readily detectable and sometimes greatly elevated concentrations of PCBs in their edible tissues. These same species do not exhibit a high prevalence of hepatic or other neoplasms (Eaton et al. 1986 in Gulf of Maine Council 1994).

We found almost nothing describing ecosystem impacts from PCBs.

We did not encounter any data quantifying economic losses due to PCBs. However, it seems reasonable to assume that health warnings related to consumption of lobster tomalley or bluefish may have had some level of "chilling" effect on overall consumption, harvesting and price of catch.

The limited amount of data were not sufficient to indicate any measurable cultural impacts.

As mentioned above, the original sources of PCBs have been curtailed. Remaining PCBs are released to the marine ecosystem through run-off, atmospheric deposition and re-mobilized sediments. Sediments can be expected to be a source for uptake into the food web and transfer back to humans well into the future.

Estimates of PCB loading to Massachusetts Bay suggest that it is dominated by atmospheric inputs. Menzie-Cura (1991) base their summary on 1970s data and suggest that, because production of PCBs declined in the late 1970s, it is likely concentrations have decreased.

The primary pathways into the Gulf of Maine are through atmospheric deposition, continuing discharge from sites which were historically contaminated and from resuspended sediments. The pathways from the environment to biota are through ingestion of sediments or trans-dermal movement in benthic species or through bioaccumulation within the food chain.

Most sampling done for PCBs measures total PCB concentration, while there are clear differences in half-life, uptake, and impacts from the 210 different forms. Very little information is available assessing the impacts of the individual forms.

There is very limited information available on the current input to the Gulf of Maine from nonpoint sources.

Dioxins and Furans including:

polychlorinated dibenzodioxins (PCDD),

tetrachlorodibenzodioxins(TCDD) and

polychlorinated dibenzofuran (PCDF).

 

There are 75 different isomers of dioxin, the most toxic of which is the chlorinated 2,3,7,8-TCDD isomer. Dioxins are found in chlorophenols, certain pesticides and in PCB mixtures. They are highly persistent in the environment, have a strong affinity for fine-grained sediments and accumulate in biological tissue. These contaminants accumulate in fish in proportion to the body lipid content and the age of the animal. PCDDs are particularly resistant to biological breakdown, concentrate in fatty tissues and are not readily excreted. Consequently, repeated exposures can rapidly increase body burdens.

The Department of Environmental Protection in Maine monitors rivers which flow past pulp and paper mills for dioxin and they have reported TCDD and dioxin toxic equivalents (DTE) in all fish samples collected below point source discharges and rivers in Maine. Concentrations in these fish exceed Maine’s acceptable concentrations to avoid an increased risk of cancer and reproductive effects. Consequently, the state has issued fish advisory warnings for 235 miles of rivers. Dioxins have been discovered in the tomalley of lobsters taken in several locations in Maine which led to a state public health advisory warning in 1994 which is still in place today. We have been unable to locate similar data for other areas where pulp mills are currently or historically been in operation.

There are increasing concerns about the effects of exposure to low levels of chlorine-containing chemicals on the development of living creatures, including humans. According to the US EPA, consumption of contaminated fish is a major source of human exposure to toxic chemicals such as dioxin.

The 1996 Gulfwatch report, which measures concentrations of contaminants in mussels around the Gulf of Maine, reported that the summed chlorinated biphenyls and polychlorinated dioxins (PCDD/PCDF TEQs) are well below the Canadian 20 pg/g tolerance level designed to be protective of human health for the consumption of seafood.

It has been shown that some dioxin and furan compounds are toxic to some animals at exposure levels of less than one part per billion (Eaton et al. 1994 in St. Croix 1997). PCDDs are extremely toxic to some animals with cumulative effects of small doses of primary concern. Population impacts were not described in the papers reviewed.

We were unable to identify economic impacts from the articles surveyed. As with other fishery advisories or closures, it is reasonable to assume that there is some level of impact on fishermen and consumers.

The Passamaquoddy Tribe at Pleasant Point, Maine, expressed concerns about dioxins in the St. Croix River, indicating that they had not seen the results of any testing of fish tissue from that river (Leighton 1998, pers. comm.). As mentioned earlier, members of Tribal/First Nation communities typically consume more of fish than just the muscle tissue. Consequently, it is important for their needs to sample for the entire body burden. A tribal representative expressed concerns about discharges from the Georgia Pacific wastewater treatment plant and its potential for discharging persistent organic pollutants. Their perception is that the various governmental agencies are not providing sufficient monitoring of conditions in the St. Croix (Leighton 1998, pers. comm.).

Polychlorinated dibenzodioxins (PCDD) and polychlorinated dibenzofuran (PCDF) originate from a number of anthropogenic sources. The latter include industrial sources such as companies manufacturing chlorinated chemicals; pulp and paper mills; dry cleaning distillation residues; thermal or combustion sources such as municipal waste incinerators, automobile exhaust, burning of fossil fuel for thermal generation by homes and industry and escape from contaminant reservoirs such as sewage sludge, compost and contaminated soils (Jones in press).

Dioxins enter the environment through accidental release during chlorophenol production, aerial application of herbicides, smoke from combustion in municipal and industrial incinerators and in the effluent of kraft bleach paper mills. Pulp and paper mills that use elemental chlorine in their bleaching processes are a well-documented source of dioxins and furans. Another key source is the incineration of plastic, e.g., from municipal incinerators and at some landfills. Contaminants produced and released from burning may be transported considerable distances by winds. Even seemingly benign activities such as washing clothes may release dioxins to sewers, WWTPs and receiving environments, as dioxin has been detected in clothing made from cotton grown with some pesticides (World Wildlife Fund, Canada 1995a in St.Croix Estuary Project 1997.) In Maine, the largest volumes of chlorines discharged into freshwater are associated with the old Great Northern pulp mill in Millinocket, which legally discharges 14,000 pounds of chlorine into the Penobscot River annually (Conkling 1995).

We were unable to identify an overall loading to the Gulf. The available information focuses on specific point discharges rather than receiving waters. Little quantitative information is available on nonpoint source loadings.

The pathways traveled to reach the Gulf of Maine depend on the type of source. Pipes from industrial operations may discharge directly in estuarine or river waters. Residue from incineration reaches the Gulf principally via atmospheric deposition.

Particular gaps are the total loadings, especially those from nonpoint sources. Because there are such a wide variety of forms of these chemicals, there is little information about the human health and ecosystem impacts from particular isomers. Consequently, there are virtually no data on additive or synergistic effects.

Much of the information related to metals discusses them in an aggregate manner. Consequently, the generalize discussion below is designed to reflect those discussions and limit duplication in subsequent portions of this paper. Information or data on specific metals will be review under those headings.

Heavy metals, or trace metals, have been major environmental contaminants since the beginning of the industrial revolution. Several are highly hazardous to aquatic life and humans. Being basic elements, they do not biodegrade and are very long-lived in the environment. Many New England rivers and estuaries were heavily loaded with metals during the 19th century from industries located on rivers in the region. Heavy metals include those that are essential to biological processes (e.g., copper, chromium, nickel, and zinc) and those that are non-essential (e.g., cadmium, mercury and lead). The non-essential metals are the most toxic and of greatest concern (Sowles 1997c).

For the majority of the Bay of Fundy, heavy metals in the sediments are at or near natural levels for unpolluted coastal sediments. The anomalies include an area near Grand Manan, where higher concentrations of some metals result naturally from their occurrence in rock formations in the area. Off Saint John is a disposal site for dredged harbor sediments where concentrations of metals are higher than normal. Levels of some metals are also higher in sediments in Passamaquoddy Bay because fine contaminated sediments in the Saint John River plume are swept into the area by coastal currents and deposited there. Heavy metals have been detected in the meat of scallops taken from Saint John Harbor (Robinson 1996 cited in Saint Croix Estuary Project 1997). Satellite images of the Kennebec River show a plume of contaminated sediments at the river’s mouth which ultimately brings toxic metals into the Gulf of Maine (Conkling 1995). Trace metals are found in high concentrations in New Hampshire’s estuarine sediments (Jones in press).

Blue mussels, indigenous species to the Gulf of Maine, are used as a bioindicator of contaminants at 33 sites throughout the region as part of the Gulfwatch program. Field-exposed mussels were observed to take up cadmium, copper, mercury, silver, chromium, lead, nickel, and zinc to different extents. Four metals that are indicative of anthropogenic activities, silver, copper, chromium, and mercury, are found in higher concentrations in Boston and New Hampshire mussels than those further north. The body load of these mussels represents what is in the water currently either from resuspended sediments or new inputs ( Conkling 1995). Blue mussels from Boothbay Harbor, ME, had large kidney concretions resulting from the accumulation of heavy metals. The mean body burden of lead in Boothbay Harbor mussels was the highest of ten sites sampled along the Maine coast (Larsen 1992).

The Maine Department of Environmental Management monitors heavy metal concentrations in lobster meat and tomalley annually.

Moderate to high concentrations of trace metals were found in Casco Bay, Boston Harbor, Salem Harbor and Quincy Bay during the 1984–1987 sampling of trace contaminants in fish livers by the NOAA National Status and Trends, Benthic Surveillance program (Gottholm and Turgeon 1992).

Copper, cadmium, zinc, and total mercury concentrations were determined for liver, kidney, and muscle tissues sampled from Bay of Fundy harbor porpoises in 1989 (Johnston 1995 in Wells et al. 1995). Copper and zinc in Bay of Fundy porpoises were similar to values previously published for conspecifics from other locations (Falconer et al. 1983 in Wells et al. 1995) and to other cetaceans in Canadian waters (Wagemann et al. 1990 in Wells et al. 1995).

The U.S. Food and Drug Administration (FDA) has published a series of "Guidance Documents" for cadmium, chromium, lead and nickel. These are alert levels and by themselves do not warrant the issuance of health advisories. For 1996, no metals sampled as part of the Musselwatch program in U.S. waters, approached the guideline levels. There are also screening values prepared by the US EPA for cadmium, mercury, and selenium; 11 organochlorine compounds; one chlorophenoxy herbicide; total PCBs; and dioxins/dibenzofurans. None of the contaminants sampled at 1996 Gulf watch stations exceeded these screening values, including metals (Chase 1997).

(CEC 1997a)

(Sowles 1997c).

Arsenic is widespread in the environment and is continuously changing form and location through oxidation, reduction or mobilization. Some forms are more bioavailable than others and that availability is greatly affected by physical aspects of the environment. Arsenates adsorb onto sediments rich in organic matter much more readily than do other forms. Arsenate is the typical form found in oxygenated situations; arsenite is more typically found in anaerobic conditions (Eisler 1988). Arsenic may be bioconcentrated at the bottom of the food chain, but does not seem to biomagnify (Dillon 1984)

Cadmium is a natural element in the earth’s crust and is usually found as a mineral combined with other elements such as oxygen in the form of cadmium oxide. It does not corrode easily and has many uses in industry and consumer products, e.g., batteries, pigments, metal coatings and plastics. Cadmium enters the air from mining and industrial activities, burning of coal and disposal of household wastes and can travel via the atmosphere for long distances before being deposited. It binds strongly to particles and some cadmium-based compounds will dissolve in water. Cadmium does not break down in the environment but can change forms. Fish, plants and animals take up cadmium from the environment and it will remain in an organism’s system for an extended period of time. Exposure of many years to very low levels will build up significant body burdens.

Cadmium was detected at low levels in most east coast seabirds. The highest levels were found in the kidneys of Double-crested Cormorants at Heron Island in Chaleur Bay in 1970–71. The cormorants have not been retested since then (Noble 1990).

Long et al. (1995) compiled data from numerous modeling, laboratory and field studies performed with marine and estuarine sediments. From these data they developed guideline values (effects range low (ERL) and effects range medium (ERM) to provide a sense of the potential impacts of contaminants on the biota. For a number of contaminants, they established concentrations which would produce rare (below the ERL), occasional (between ERL and ERM levels) and frequent (above ERM) incidences of adverse effects. At our request, the USGS segmented data using the ERL/ERM thresholds provided by Long et al. Unpublished material from the USGS contaminated sediment data set show one site in Casco Bay above ERM and several locations in Boston Harbor, Salem Harbor Great Bay and the southern Maine coast between the ERM and ERL thresholds.

As shown in the table above (CEC 1997a), cadmium is listed as a probable carcinogen and has been implicated in reproductive, neurological/behavioral, immunological, respiratory and kidney difficulties in humans.

Research in the Baltic Sea found that cod which have elevated levels of cadmium in liver and kidney tissue, also had externally visible skeletal deformities such as compressions of the spine and deformities of the jaw (Land and Dethlefsen 1987 in Langton et al. 1994).

MacAdie (1995) summarized information available on cadmium inputs into the Gulf of Maine by pathway as presented in the table below.

Estimates of cadmium loads to Massachusetts and Cape Cod Bays indicates that permitted discharges accounted for between 17–34 percent of the total load. Nonpoint sources appeared to be relatively important with runoff accounting for 30–66 percent and the atmospheric inputs were estimated to be between 17–31 percent (Menzie-Cura 1991).

Chromium is found in a number of forms in the environment. It is an essential element in mammals for a number of life-sustaining processes. Excessive amounts of some of the chemical forms, however, can prove toxic or produce a range of carcinogenic, mutagenic and teratogenic effects.

Unpublished material from the USGS contaminated sediment data set show levels above the ERM of Long et al. (1995) in Boston Harbor, Salem Harbor, Great Bay, off Saco and in Casco Bay. Levels between the ERM and ERL were found in several sites in Casco Bay and in other scattered locations along the Maine coast. The NOAA Status and Trends Program found Salem Harbor sediments to have the highest concentrations nationally (Gottholm and Turgeon 1992).

The Status and Trends Musselwatch program found Boston and Salem Harbors to be among the 20 most contaminated sites in U.S. Coastal waters (Capuzzo 1995). With the exception of Frenchmans Bay, all winter flounder livers in the Gulf of Maine had chromium concentrations at or above the U. S. (Gottholm and Turgeon 1992).

elevated levels of chromium in the Great Bay estuary (NH), the Saco River (ME) and Salem Harbor (MA) are attributed to the input of tannery wastes over the years (Capuzzo 1995)

As mentioned above, chromium, at elevated levels, can have carcinogenic, mutagenic or teratogenic effects. Some forms have been linked to changes in enzyme activity, lowered resistance to pathogens, neurological changes, and disrupted feeding (Eisler 1988).

Elevated levels of chromium has also been noted to inhibit photosynthesis in plants and result in alterations in populations and their dynamics (Eisler 1988)

The NOAA Status and Trends Program found the sediments of Salem Harbor and Quincy Bay (both in Massachusetts) to have higher levels of copper than other areas in the U.S. portion of the Gulf of Maine (Capuzzo 1995). Gottholm and Turgeon (1992) reported that the mean concentration levels of copper in Salem and Boston Harbor area were substantially higher than the mean concentrations anywhere else in the Gulf.

The Musselwatch program found Boston Harbor and Salem Sound to be among the 20 most contaminated sites in U.S. Coastal waters (Capuzzo 1995) but Gottholm and Turgeon (1992) note that there is little variation in mean concentration levels of copper in mussel tissue throughout the Gulf. Winter flounder liver concentrations range from a low of 15 ppm at Quincy Bay to a high of 69 ppm at Casco Bay.

Copper is an essential element for animals. Excess ingestion, however, leads to accumulation in tissues, particularly in the liver, where it may disrupt that organ’s metabolism. Toxic symptoms appear when the liver accumulates 3 to 15 times the normal level of copper. High levels also inhibit essential enzymatic action. (Eisler 1988). Copper does not appear to be mutagenic but is a teratogen and possible carcinogen.

Copper can be acutely toxic, primarily through its caustic nature, as is evidenced by its use in anti-fouling paints for boat bottoms. Ecosystem impacts were poorly defined in the papers reviewed.

Most of the lead which reaches Massachusetts Bay is deposited from the atmosphere. Urban run-off and combined sewer overflows also contribute a significant portion of the loading. Permitted discharges accounted for less than 10 percent of the total load to the Bay (Menzie-Cura 1991). Atmospheric deposition of lead has decreased, apparently due to restricted use of leaded gasoline. In Canada, it has been reported that emissions decreased 86 percent between 1973 and 1987 (Hillborn and Still 1990).

MacAdie (1995) provides an estimate of inputs of lead into the Gulf of Maine. These estimates are summarized in the table below.

Lead does not biomagnify to a great extent in food chains, although accumulation by plants and animals has been documented. Older organisms typically contain the highest tissue lead concentrations, with the majority of the accumulation in the bony tissue of vertebrates.

Unpublished material from the USGS contaminated sediment data set show levels above the ERM in Boston and Salem Harbors, Great Bay, and Portsmouth/Kittery. Areas with concentrations between the ERM and the ERL include Massachusetts Bay, Great Bay, Casco Bay, Penobscott Bay and other scattered sites at river mouths in Maine. The sediments of the following harbors showed high concentrations of lead as surveyed by the NOAA Status and Trends Program (Capuzzo 1995): Cape Ann, Salem Harbor, Boston Harbor and Quincy Bay (all in Massachusetts.

The 1995 Gulfwatch mussel sampling program found a trend for higher concentrations of lead in population centers in Massachusetts and New Hampshire. Lead concentrations in mussels at half of the sites sampled in 1996 in Maine exceed that state’s reference concentrations. Concentrations of lead were consistently low among sites in New Brunswick and Nova Scotia (Chase 1996).

High concentrations of lead in mussels from sites in New Hampshire may be associated with Portsmouth Naval Shipyard. Sites in Portsmouth Harbor that contain elevated lead concentrations are in close proximity to the Jamaica landfill and the defense re-utilization and Marketing Office on Seavy Island. Both are known sources of lead contamination from past discharges of waste plating sludge and disposal of lead batteries (Chase 1996).

The U.S. Food and Drug Administration released a "Guidance Document" in 1993 for lead (USFDA 1993 in Chase 1996). Gulfwatch samples from 1996 showed levels of lead in all replicates from Boston Inner Harbor which exceeded these thresholds. (Chase 1996). The Status and Trends Musselwatch program found Boston Harbor to be among the 20 most contaminated sites in U.S. Coastal waters (Capuzzo 1995).

Because lead does not tend to biomagnify, to have impacts, there must be direct exposure to significant amounts of lead compounds. Children are the most susceptible among humans. In cases of lead poisoning, there has typically been evidence of neurological damage and disrupted blood chemistry (Eisler 1988).

Mercury has become a contaminant of significant concern for a number of reasons; the impacts it can have on humans and species of commercial importance, its relatively wide-spread presence and its ability to accumulate in the marine food web

The US EPA Report to Congress (1998) reports that since pre-industrial times the amount of mercury deposited into the global marine environment has increased approximately 4-fold. Mercury accumulates very efficiently in the aquatic food web. Predatory organisms at the top of the food web generally have higher mercury concentrations. Toxicity is influenced by the form of mercury, the environmental medium, environmental conditions, the sensitivity or tolerance of the organism and the life history stage. Inorganic mercury is less acutely toxic to aquatic organisms than methylmercury, but the range in sensitivity among individual species for either compound is large. Toxicity was found at elevated temperatures, lower oxygen content, reduced salinities in marine environments, and in the presence of metals such as zinc and lead. Nearly all of the mercury that accumulates in fish tissue is methylmercury. Inorganic mercury, which is less efficiently absorbed and more readily eliminated from the body than methylmercury, does not tend to bioaccumulate (US EPA 1998).

In general, toxic effects occur because mercury binds to proteins and alters protein production or synthesis. Toxicological effects include reproductive impairment, growth inhibition, developmental abnormalities, and altered behavioral responses. Early life cycle states are the most sensitive. Mercury can be transferred from tissues of the adult female to developing eggs.

Fish consumption dominates the pathway for human and wildlife exposure to methylmercury. There is a plausible link between anthropogenic releases of mercury from industrial and combustion sources in the United States and methylmercury in fish but concentrations of methylmercury in fish also result from existing background exposure. Because of the nature of both its chemical parameters and its mode of transport (i.e., atmospheric deposition), it is not possible to quantify how much of the methylmercury in fish is contributed by any one location or even any one country. Fish-eating birds and mammals are more highly exposed to mercury than any other wildlife.

Unpublished material from the USGS contaminated sediment data set show concentrations of mercury above the ERM in Boston Harbor, Massachusetts Bay, Salem Harbor, Great Bay and scattered sited along the Maine coast. Many of these same sites also show concentrations between the ERM and the ERL.

The NOAA Status and Trends Program found that the sediments of the following harbors showed high concentrations of mercury; Salem Harbor, Boston Harbor and Quincy Bay (Capuzzo 1995).

A recent review of sediments in Maine’s coastal sediments and rivers indicate that the Upper Penobscot Estuary and River at Orrington have mercury concentrations that exceed—by orders of magnitude—any others found in the country (Land and Water Resource Council 1998).

Preliminary comparison of concentrations of mercury in mussels from Maine with the rest of the country indicate high concentrations and confirms similar data that Maine waters in general have abnormally high concentrations of mercury for North America (Land and Water Resources 1998). These levels appear to be associated with historical or recent industrial activity.

Mussel watch data indicate that concentrations in mussels in the Gulf are unusually high compared with other locations. Mean values of mercury in mussels from various coastal regions worldwide are about 0.1 to 0.4 ug/g dry weight (Kennish 1997 in Chase 1997). Over half of the Gulfwatch samples exceed the upper limit of this estimate. Maine mussels contain significantly more mercury in their tissues than those collected from either the east or west coast of the United States. (Land and Water Resource Council 1998).

Levels of mercury contamination in striped bass in the Saint John River are almost five times higher than what is considered acceptable for human consumption (Conkling 1995).

Elevated levels of mercury were detected in the eggs of seabirds in 1971–72 from New Brunswick, Bay of Fundy area and in the livers of Double-crested Cormorants collected in Chaleur Bay, New Brunswick, in 1969. Data to determine whether levels have declined since that time is lacking (Noble 1990).

Marine mammal tissues have some of the highest concentrations of mercury found in all marine organisms, with the liver generally having the highest total mercury concentration. Although many juvenile and adult marine mammals feed primarily on fish, which contain high percentages of methylmercury, high concentrations of inorganic mercury are found in adult mammal specimens. Apparently, adult marine mammals can mineralize methylmercury into inorganic mercury. Juvenile marine mammals have lower concentrations of total mercury than adults; but unlike fish and invertebrates, the percentage of methylmercury is higher in juvenile mammals.

Mercury levels measured in the early 1990s in harbor porpoises and seals were lower than those measured a d