Summary

Description

Mercury Hg is a highly mobile contaminant with the ability to cycle through land, air and water. One of its organic forms, methlymercury MeHg bioaccumulates and biomagnifies in upper trophic level wildlife, such as piscivorous birds see Meyer et al. 1995, Scheuhammer 1987,1991. The northeastern United States is at particular risk to elevated levels of mercury deposition; one of the highest exposure areas predicted in these models is the southeastern corner of New Hampshire. The Loon Preservation Committee LPC routinely conducts opportunistic collections of abandoned loon eggs as part of its monitoring program in New Hampshire. Analysis of 36 loon eggs collected in the mid1970s by LPC and 120 eggs collected in 199297 detected mercury at levels that could impact reproductive success Haseltine et al 1983, LPC unpubl data. In 1998, LPC was tasked by the U.S. Fish and Wildlife Service Project ID: 5F209550002.0 to sample inviable loon eggs statewide as part of the Northeast Loon Study Working Group. This group is conducting a national study on the distribution and abundance of Hg in the environment as measured through common loons. In 1998, 61 abandoned whole eggs were processed and analyzed for total mercury. Fiftyfour percent n33 of these did not exhibit elevated Hg levels and were within the no observed effects level 0.5 ppm Thompson, 1996. However, 36 of the eggs laid n 22 were above the lowest observed effects level 0.5 ppm and 9.8 of eggs n6 showed levels that may cause reproductive impairment 1.0 ppm Thompson 1996, Barr 1986, BRI unpublished data. Eggs collected in New Hampshire in 1998 support the conclusions of the USEPAs mercury report and validate the risk modeling within the state. Recent studies by Burgess et al. 1998 correlate lowered reproductive success in loons with elevated Hg levels. Due to high Hg levels existing within the state, LPC recommends further monitoring of eggs, and comparing egg Hg levels and blood Hg levels of banded loons with historic reproductive success of loon pairs on New Hampshire territories.