Gulf of Maine Projects

Final Report: Evaluation of the Gulfwatch Monitoring Program

Table of Contents

INTRODUCTION.............................................................5
    Rational.............................................................5

    Gulfwatch Objectives.................................................6

METHODS..................................................................8

    1995 Sampling Locations .............................................9

    Field Procedures.....................................................9

        caged mussels....................................................12

        indigenous mussels...............................................13

    Laboratory Procedures................................................13

    Analytical Procedures ...............................................13

        metals...........................................................13

        organic..........................................................15

    Quality Assurance / Quality Control..................................17

    Statistical Methods .................................................17

RESULTS AND DISCUSSION ..................................................19

    Field operations and logistics ......................................19

    Contaminants ........................................................19

        Metal contaminants...............................................19

            A. Spatial variation in metal concentration: comparison of
                indigenous mussels ......................................19

                Silver ..................................................23

                Lead ....................................................25

                Chromium ................................................25

                Zinc ....................................................26

                Nickel ..................................................26

                Mercury .................................................26

                Cadmium .................................................28

                Copper ..................................................28

                Iron and Aluminum .......................................30

            B. Short term exposure: transplant experiment................32

                Massachusetts ...........................................32

                New Hampshire ...........................................32

                Maine ...................................................32

                New Brunswick ...........................................33

                Summary of metal concentration changes...................40

                Steady state tissue metal concentrations.................41

        Organic contaminants ............................................45

            A. Spatial variation in organic concentration: comparison
                of indigenous mussels ...................................45

                Polyromatic hydrocarbons ................................50

                Polychlorinated Biphenyl ................................50

                Pesticides ..............................................52

            B. Short term exposure: transplant experiment................54

                Massachusetts............................................54

                New Hampshire............................................54

                Maine....................................................55

                New Brunswick ...........................................55

                Summary of organic concentration changes.................59

                Steady state tissue organic concentrations...............59

    Acceptable levels and standards of mussel contamination..............60

    Growth and Condition Index ..........................................63

        Shell morphology and condition index: indigenous mussels.........63

        Shell growth and condition index: caged mussels..................68

            Shell growth ................................................68

            Condition index .............................................73

CONCLUSIONS .............................................................75

ACKNOWLEDGEMENTS ........................................................78

REFERENCES ..............................................................78



APPENDIX A: Methods for mussel extraction and analysis of organic
contaminants.............................................................84

APPENDIX B: Quality assurance / Quality control protocol.................94

APPENDIX C: Tissue concentration of heavy metals........................100

APPENDIX D: Tissue concentration of polyaromatic hydrocarbons...........104

APPENDIX E: Tissue concentration of polychlorinated biphenyls...........116

APPENDIX F: Tissue concentration of chlorinated pesticides..............127

Introduction

Rational

The Gulf of Maine extends from Cape Sable, Nova Scotia, through New Brunswick, Maine, and New Hampshire to Cape Cod, Massachusetts and includes the Bay of Fundy and Georges Bank. The combined primary productivity of seaweeds, salt marsh grasses, and phytoplankton make it one of the worlds most productive system that supports a vast array of animal species, including many species of invertebrates, fish, seabirds, and marine mammals, some of great commercial importance. Commercial fisheries and aquaculture are its principal income generating enterprises, although tourism is very important source of income to many small coastal communities. As coastal populations around the Gulf and its watersheds have increased, agricultural lands have been converted to industrial and residential developments. Such changes in land use and increases in population have contributed to the deteriorating quality of sections of the coastal environment (GMCME, 1992; Dow and Braasch, 1996). Inputs from non-point source and point source pollution are a significant threat to the near shore environment of the Gulf (GMCME, 1992; Dow and Braasch, 1996). Growth in industrial activity during the 20th century has resulted in a rapid increase in inputs from chemicals, either mobilized or synthesized by man, into the estuarine and coastal environments. Many of these chemicals are bioaccumulated to concentrations significantly above ambient levels. Furthermore, some of these environmental contaminants may also be present at toxic concentrations, and thus induce adverse biological effects.

In order to protect water quality and commercial uses in the Gulf of Maine, the Agreement on the Conservation of the Marine Environment of the Gulf of Maine was signed in December, 1989 by the premiers of Nova Scotia and New Brunswick, and the governors of Maine, New Hampshire and Massachusetts, establishing the Gulf of Maine Council on the Marine Environment. The overarching mission of this council is to maintain and enhance the Gulfs’ marine ecosystem, its natural resources and environmental quality.

To help meet the council’s mission statement the Gulf of Maine Monitoring Committee was formed and charged with the development of the Gulf of Maine Environmental Monitoring Plan. The monitoring Plan is based on a mission statement provided by the council:

It is the mission of the Gulf of Maine Environmental Quality Monitoring Program to provide environmental resource managers with information to support sustainable use of the Gulf and allow assessment and management of risk to public and environmental health from current and potential threats.

Three monitoring goals were established to meet the mission statement:

(1) To provide information on the status, trends, and sources of risk to the marine environment in the Gulf of Maine;

(2) To provide information on the status, trends, and sources of marine based human health risks in the Gulf of Maine; and

(3) To provide appropriate and timely information to environmental and resource managers that will allow both efficient and effective management action and evaluation of such action.

In support of the mission and to meet the desired goals a project named Gulfwatch was established, to measure chemical contamination Gulfwide.

Gulfwatch Objectives

Gulfwatch is presently a program in which the blue mussel, Mytilus edulis, is used as an indicator for habitat exposure to organic and inorganic contaminants. Bivalves, such as M. edulis, have been successfully used as indicator organisms in environmental monitoring programs throughout the world (see NAS, 1980; NOAA, 1991; and Widdows and Donkin, 1992) to identify variation in chemical contaminants between sites, and contribute to the understanding of trends in coastal contamination (NOAA, 1991; O’Connor, 1992; O’Connor and Beliaeff, 1995; Widdows et al., 1995). The blue mussel was selected as the indicator organism for the Gulfwatch program for the following reasons:

(1) mussels are abundant within and across each of the 5 jurisdictions of the Gulf Program and they are easy to collect and process;

(2) much is known about mussel biology and physiology;

(3) mussels are a commercially important food source and therefore a measurement of the extent of chemical contamination is of public health concern;

(4) mussels are sedentary, thereby eliminating the complications in interpretation of results introduced by mobile species;

(5) mussels are suspension-feeders that pump large volumes of water and concentrate many chemicals in their tissues; therefore the presence of trace contamination is easier to document; and the measurement of chemicals in bivalve tissue provides an assessment of biologically available contamination that is not always apparent from measurement of contamination in environmental compartments (water, sediment, and suspended articles).

Gulfwatch has taken two approaches to using marine mussels as bioindicators of anthropogenic contamination. During the first two years of the program (1991 - 1992), both transplanted and native mussels sampled from areas adjacent to the transplant sites were analyzed for organic and inorganic contaminants (GMCME, 1992). Transplanted mussels were initially collected from relatively pristine sites in each jurisdiction, moved to sites selected for monitoring, and held there for approximately 60 days. Because of the logistics and the analytical costs, only two sites per jurisdiction could be monitored each year using this transplant technique. However, transplant experiments provided an assessment of the short-term exposure (on the order of weeks to months) to bioavailable contaminants throughout the region. In 1993 and 1994, only indigenous mussels were sampled, although a greater number of sites were monitored compared to the years when mussels were transplanted (GMCME, 1996a, 1996b). Sampling of native mussels provided an assessment of long-term exposure to bioavailable contaminants (on the order of months to a year). The 1995 sampling year followed the protocol for 1991 and 1992, sampling transplanted and indigenous mussels from two sites in each jurisdiction.

In addition to documenting the level of contaminants in mussel tissue, biological variables, including, shell growth and condition index, were measured as a means to determine the response of organisms to stress under different concentrations of contaminant burden. Growth is often one of the most sensitive measures of a contaminants’ effect on an organism (Sheehan, 1984; Sheehan et al., 1984; Howells et al., 1990 ). Shell growth has often been used as a measure of environmental quality and pollution effects as the rate of growth is a fundamental measure of physiological fitness / performance (Widdows and Donkin, 1992; Salazar and Salazar, 1995) and therefore, is a direct, integrative measure of the impairment of the organisms physiology. Condition index (CI) was used as an indicator of the physiological status of the mussels. It relates the tissue wet weight to shell volume and is a measure traditionally used by shellfishery biologists (Widdows, 1985). Because gonadal weight is a significant contributor to total body weight just prior to spawning, CI also reflects differences in the reproductive state of the sampled mussels. Since gonadal material tends to have low concentrations of metals (LaTouche and Mix, 1981), tissue metal concentrations may be reduced in mussels having a high CI due to ripened gonads. Organic contaminants, however, would tend to partition into both somatic and gonadal lipids, and may be less impacted by changes in CI that are due to the presence of ripe gametes. Since variable amounts of ripe gametes may be found in some mussel populations even in late fall (Kimball, 1994), the relationship between CI and contaminant concentrations must be carefully considered.

The objective of the first two years (1991 and 1992) of the Gulfwatch program was to evaluate the feasibility of the project and the level of cooperation required through collecting comparative data from different locations in the Gulf of Maine. The sites that were selected fell into two categories; test sites that were suspected or known to be contaminated and reference sites that were free of any known contaminant source. After the success of the pilot studies in 1991 and 1992, it was recognized that there should be a broader or Gulf-wide orientation of the mussel watch in addition to known contaminated and reference sites within each jurisdiction. As such, a three year cycle was initiated in 1993. In 1993 and 1994 the sample design was expanded as described above. Native mussels were sampled in as many as 7 new locations within each jurisdiction (state or province), where feasible, to increase the geographic coverage. However, one location in each jurisdiction was chosen as a baseline station, to be resampled every year. This approach increased the chance of locating unforseen environmental contamination. Transplant experiments were again conducted at two sites in each jurisdiction in 1995. This three-year cycle, with transplants being conducted at two sites during one year and indigenous mussels alone being sampled at 2-7 sites per jurisdiction during the other two years, will be repeated for the remaining years of the Gulfwatch Program. This sampling design will allow the Program investigators to assess both short-term and long-term contaminant exposures.