This evening I will be discussing some of the findings of the Exposure to Mercury in West Virginia – Final Public Health report, WVDHHR’s response to the comments and the report conclusions and recommendations. 

Man’s activities put more mercury in the environment than would otherwise naturally occur. Exposures to mercury can be reduced, but not eliminated, by restricting the emissions associated with man’s activities.

The health effects from mercury exposures are of special concern for unborn babies and young children because it is a neurotoxin.  The public health report estimated possible health effects from exposure to children and adults, including women of child-bearing age and the effect on developing fetuses. Exposures to mercury in air, drinking water, surface water, sediment, soil and food, including fish, were considered in the public health report.

Mercury spills were not included in this report because each incident is different and no general estimates of exposure can be made.  People have been exposed to hazardous amounts of mercury without being aware of their exposure because the vapors are colorless and odorless.

Once in the environment, mercury constantly cycles through the air, soil, water, and biota. It is slowly removed from the environment. It is important to note that mercury can be changed to methylmercury in moist environments. Methylmercury in fish is an important component of man’s exposure to mercury.

The public health report showed that 82-99% of exposure to mercury is from eating fish. The concentration of mercury in fish and the amount of fish eaten are major factors for man’s exposure to mercury. Mercury exposure in air is not at levels where breathing it might cause adverse health effects.  This held true even for people breathing air near a chlor-alkali plant. The amount of mercury in the air becomes important in the methylation and bioaccumulation processes resulting in mercury accumulation in fish tissue. Even though everyone is exposed to mercury, the amount of exposure in terms of milligrams of mercury per body weight per day is the important factor to determine if adverse health effects might occur.

People who do not eat fish are exposed to  mercury (other than from mercury spills) at levels unlikely to cause adverse health effects. People who eat a lot of fish containing mercury may be at risk for subtle neurological effects.  Various fish consumption scenarios are presented in Table 9 of the report indicating different number of meals and different mercury concentrations in fish tissue. Note that a 1 year old child would need to eat four ¼ pound fish meals per month containing 0.25 mg/kg or more to exceed the Minimal Risk Level. Similarly a woman of child bearing age would need to eat about 12 - ½ pound meals per month of fish containing 0.25 mg/kg mercury or more  to exceed the Minimal Risk Level.  Basses are the fish containing the most mercury in West Virginia and the average is 0.25 mg/kg.  Even when the MRL is exceeded, the exposures are not necessarily at levels where adverse health effects might occur. Subtle neurological effects are apparent only with carefully-designed scientific study. These effects are detected using attention, fine-motor functioning, language, drawing, and verbal memory tests.

Comments were received from two organizations and one individual before the end of the comment period.  Many of the comments received were suitable for WVDEP response.  Some comments were out of the scope of the Bureau’s authority, such as the request to eliminate coal preparation plants and coal-fired power plants. The report points out that plant-based sources of omega-3 available.  They are: flaxseed, canola oil, and walnuts.  The type of omega-3 fatty acids found in these foods are inefficiently metabolized to the essential omega-3 fatty acids found in fish.  Rates of deep-ocean mercury removal are unknown because the global mercury cycle is not understood.  The EPA estimates it may take 5 to 30 years after mercury emissions are changed for a steady-state to be reached in aquatic environments.

Even with this limited data, WVDEP should continue to reduce mercury emissions, due to potential adverse health effects from mercury exposure. WVDEP – Water and Waste Management should re-sample fish tissue for mercury residues, as planned, in watersheds where the most restrictive fish advisories occur. WVDNR and/or WVDEP should collect additional data about West Virginian’s fish consumption habits.

WVDHHR encourages the removal and proper disposal of mercury-containing materials from homes, schools, and workplaces.

West Virginian’s should eat fish as part of a well-balanced diet while following fish advisories to avoid harmful amounts of chemicals. People should be especially careful to follow fish advisories during a woman’s childbearing years and when infants and young children are in the household. West Virginian’s, particularly children, should be educated to avoid handling elemental mercury and what should be done should a spill occur. People who eat a substantial amount of fish or work with mercury should mention this to their dentist or other health care provider when mercury-containing dental amalgams are recommended. This is especially recommended for children 6-years-old or younger and women who are pregnant or nursing. In all cases, the choice not to use mercury amalgam should be made in consultation with a qualified dentist (and/or physician) and weighed against the risk of alternative practices or materials.