The Great Lakes Water Quality Agreement
United States Great Lakes Program Report on the Great Lakes Water Quality Agreement
- Areas of Concern
- The Clean Water Act
- Great Lakes Image Collection
- State-of-the-Lakes Ecosystem
- The Great Lakes Atlas
- 25 Years of Great Protection
[PDF 2.7Mb, 69 pages]
Fish and Wildlife Consumption Advisories Still In Place
The Great Lakes food web remains contaminated by a variety of bioaccumulative toxic substances, causing unacceptable levels of these contaminants in some fish and wildlife. Levels are lower than in the early 1970s, but still justify the issuance of public health advisories regarding fish and wildlife consumption. Advisories especially apply to vulnerable consumers, such as children, women who anticipate bearing children, and frequent consumers, such as sport fishermen and Native Americans. EPA's 1996 summary of State-issued fish advisories showed an increase of 26 percent over 1995, largely as a result of better monitoring and reporting by States. As in prior years, 100 percent of the Great Lakes waters continue to be under advisory, most of which are due to mercury, PCBs, and dioxins.
Fish tissue sampling indicate that PCB levels in Lake Huron and Lake Michigan lake trout are generally declining. In Lake Ontario, PCB levels in salmon and trout are slowly declining, resulting in some less restrictive advisories. Contaminant levels remain low in most Lake Erie fish. For Lake Superior, toxaphene is the basis for a number of advisories issued by the Province of Ontario and the State of Michigan.
Not all Great Lakes fish are safe to consume;
further toxic reduction efforts will help improve this situation
Figure 6: PCBs in Lake Michigan Lake Trout
Toxaphene was a trade name for a pesticide once heavily used in the south on cotton crops and which was also used in the Great Lakes watershed. Because of its volatility and persistence, it has been recognized as pervasive in Arctic wildlife, owing to atmospheric transport. Since the pesticide was canceled in 1982, levels have fallen across the Great Lakes except in Lake Superior, which has the highest levels known anywhere. The State of Michigan and the Province of Ontario issue a number of consumption advisories for Lake Superior fish species because of toxaphene. The distribution of toxaphene in Duluth Harbor bottom sediments suggest a local source there in recent years.
EPA, Environment Canada, and State environmental agencies are working to achieve a better understanding of the persistence of toxaphene in Lake Superior. EPA's Office of Research and Development has awarded a grant to obtain sediment cores and measure the air/water exchange of toxaphene to the Great Lakes, so as to better determine the historical trend and atmospheric contribution. EPA is also collecting sediment cores from a number of tributaries to screen for local sources and is supporting a study of toxaphene in small inland lakes near Superior for comparison. Explanations for the persistence of toxaphene in Superior include the lake's relative coldness, atmospheric transport from the south, and local pesticide use. Ongoing studies should yield scientific data to test these hypotheses during the next two years.
EPA is reviewing information indicating the possibility of adverse impacts on human health and the environment associated with exposure to endocrine disruptors. At the present time, however, there is little agreement on the extent of the problem. Based on the current state of the science, the Agency considers endocrine disruption to be a mechanism of action potentially leading to other outcomes (for example, carcinogenic, reproductive or developmental effects), routinely considered in reaching regulatory decisions. EPA thinks that identification of environmental agents that cause adverse effects as a result of endocrine disruption, as well as enhancement of our understanding of how these agents exert their effects, will improve the EPA's ability to reduce or prevent risks, particularly to children and vulnerable ecosystems. These considerations become increasingly important as we expand our risk assessment activities to incorporate a wider range of susceptible populations, multiple pathways of exposure, and mixtures of chemical substances. Further research and testing are needed to address existing gaps in knowledge concerning the consequences of endocrine disruption. Such knowledge will reduce uncertainties in the assessment of hazard, exposure, and risk.
The Agency formed the Endocrine Disruptor Screening and Testing Advisory Committee (EDSTAC) to advise EPA on the screening and testing of pesticides and chemicals for their potential to disrupt the endocrine system. EDSTAC is comprised of representatives from a cross-section of public and private organizations, such as ATSDR. The Food Quality Protection Act (FQPA) and the amendments to the Safe Drinking Water Act (SDWA), both of which were passed in the summer of 1996, require the Agency to develop a screening and testing strategy for endocrine disruptors by August 1998, implement screening and testing by August 1999, and report progress to Congress by August 2000. All EDSTAC meetings are open to the public and are being held in various locations around the country to encourage public access and involvement.
In February 1997, Illinois became the first State to develop an Endocrine Disruptor Strategy under which Illinois EPA (IEPA) is beginning to assemble and analyze key information from existing data in order to identify those chemicals which may interfere with hormones, their sources, and their quantities. A preliminary list has been developed with chemicals identified as either known, probable or suspect endocrine-disrupting chemicals. The Strategy has built-in flexibility to allow it to evolve and adapt to new research and discoveries.
Reports of malformed amphibians are increasing throughout North America since they were first observed in Minnesota in the summer of 1995. There are confirmed reports of amphibian malformation in at least 23 States and four Canadian Provinces encompassing 12 different species of amphibians. Observed malformations include missing limbs, extra limbs, under-developed limbs, and missing eyes as well as internal abnormalities in bone, muscle and organ development. Reproductive effects have not been studied, but the nature of the malformations suggest possible impacts. Population effects are also uncertain, but field observations suggest that the malformations may result in significant mortality. Global reductions and local extinctions of amphibian populations support the inference of possible population-level effects. Possible reasons for these effects include: biological stressors such as parasites; xenobiotic chemicals; and ultraviolet (UV) light. There is rising public and scientific concern that these anomalies are related to one or more environmental factors and that they may portend a heightened risk to humans. While there are no scientific data supporting such a link, neither are there convincing data to lay this concern to rest. Several State and Federal agencies and universities are working together to gather data needed to help identify the causes of these malformations.
Scientists are unclear as to why some amphibians are exhibiting malformations
Agricultural lands and other open spaces are being converted to urban areas
One of the Basin's most significant cross-cutting issues is the continuing growth of
major metropolitan areas and the sprawl of residential areas and other development. This
trend is having social, environmental, and economic impacts, many of which may threaten
the long-term sustainability of the Basin's ecosystem. Urban sprawl contributes to
polluted runoff by replacing green open spaces and farmland with paved surfaces and
requiring the building of additional roads and commuter highways; it contributes to air
pollution by boosting commuter distances and vehicle miles traveled per person; and it
results in the loss of viable habitat for animals and plants. Between 1981 and 1992, for
example, Basin farmland decreased by 9.6 percent. Areas of greatest decrease tend to be
either in close proximity to major urban areas or towards fringe areas where farmland
makes up less than 40 percent of the total land area.
|FARMLAND CONVERSION IN THE GREAT LAKES
|Land In Farms
|Land in Farms
The National Oceanic and Atmospheric Administration's Great Lakes Environmental Research Laboratory (NOAA/GLERL) is providing the U.S. leadership for the U.S./Canada Binational Great Lakes -- St. Lawrence Basin Climate Change and Variability Project to assess the physical, biological, hydrological, and socio-economic impacts of climate change and variability in the Great Lakes Basin. The Project is built around the themes of water use and management, land use and management, and ecosystem health and human health. Cross-cutting research topics include climate and physical systems, socio-economic impacts, adaptation, communication and education, and system integration. GLERL is also developing water resources models that couple the Great Lakes hydrologic cycle and atmospheric circulation, and simulate moisture storage and runoff from the 121 watersheds draining into the Great Lakes. A major achievement was the implementation of an Advanced Hydrologic Forecast System that produces probable water supply and lake level outlooks based on multiple 1 to 9 month climate projections from the National Weather Service.