Andrew Major

Assessment of mercury in waters, sediments, and biota of New Hampshire and Vermont Lakes, USA, sampled using a geographically randomized design.

We report on mercury (Hg) contamination in waters, sediments, and biota of Vermont and New Hampshire (USA) lakes measured during 1998-2000, using a geographically randomized design. Waters and sediments of 92 lakes were sampled for mercury, methylmercury, and ancillary parameters. Yellow perch (Perca flavescens) muscle tissues were analyzed for mercury on 47 of these lakes. Interannual variation in mercury was limited; only epilimnetic Hg was elevated by approximately 1.5 ng/L in 1998 over remaining years because of wet weather. Aqueous total and methylmercury concentrations were elevated in both dystrophic and eutrophic lakes over other types. Yellow perch tissue concentrations were elevated by 0.218 microg/g in dystrophic lakes over other types and were very low in eutrophic lakes. Fish tissue mercury concentrations showed no relationship to hypolimnetic or sediment mercury or methylmercury. A statistical model indicated that yellow perch tissues in 40.2 +/- 13% of lakes were likely to exceed the U.S. Environmental Protection Agency (U.S. EPA) methylmercury criterion of 0.3 microg/g, and yellow perch from New Hampshire were twice as likely to exceed the criterion as those from Vermont. Results of this study provide a regional-scale baseline against which the success of future reductions in mercury emissions can be assessed.

Mortality of common loons in New England, 1987 to 2000.

Diagnostic findings are presented on 522 common loons (Gavia immer) found dead or moribund in New England (Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont, USA) between 1987 and 2000. Common loon numbers and range in New England have decreased from historic levels over the last century due to a number of proposed factors. Goals of this study were to identify and categorize causes of mortality and quantify natural versus anthropogenic causes. The majority of identifiable mortality in chicks was from intraspecific aggression (25%) and other causes of trauma (32%). Death in immature loons was primarily from fungal respiratory disease (20%) and trauma (18%). Causes of adult loon mortality differed significantly in breeding and wintering habitats. Wintering adults primarily died of trauma (17%) and infection (11%) and had significantly poorer body condition than breeding loons. In breeding adults, confirmed and suspected lead toxicosis from ingested fishing weights accounted for almost half of all mortality. Direct anthropogenic factors accounted for 52% of loon mortality in this study. Because of high carcass recovery rates, we believe these data are a good representation of loon mortality in New England. Results highlight the importance of human influences on conservation and management of the common loon in New England.

Lead Objects Ingested by Common Loons in New England

Abstract Necropsies of Gavia immer (Common Loon) recovered lead and non-lead foreign objects from gastrointestinal tracts. Carcasses collected between 1987 and 2000 reveal that a great deal of loon mortality on lakes in New England is attributable to ingestion of lead objects. In this study, 522 carcasses were examined to inspect the types, sizes, and masses of 222 objects responsible for lead toxicosis. Most ingested lead objects were less than 2.5 cm long and weighed less than 25 g. Information on objects ingested by loons may help in development of non-toxic alternatives.