Total Mercury Concentration in Pardosa Wolf Spiders along Susquehanna River Sites

Elaine Langone Center, Terrace Room

Mercury is a persistent and common environmental contaminant that primarily originates from coal-fired power plants. Methyl mercury biomagnifies as it moves through food chains until it reaches toxic levels in apex predators. Wolf spiders are known to concentrate methyl mercury at levels far higher than what would be predicted for a terrestrial arthropod predator, sometimes exceeding levels found in fish or even piscivorous birds. Since these spiders occupy positions within detrital, terrestrial, and aquatic food chains, the pathway for mercury biomagnification remains unknown. We sampled wolf spider and other ground spider taxa at sites along the Susquehanna River near a coal-fired power plant and compared it to sites away from water that could have mercury contamination, but limited aquatic sources for mercury methylation (Centralia, PA) as well as sites less likely to have mercury contamination above background levels (agricultural fields). We sought to identify two pandemic species that could serve as an indicator for mercury contamination across these diverse habitats. Two species, Pardosa milvina and Pardosa saxatilis were found at 6 of the 20 collecting localities occupying both riparian and non-riparian locations. We analyzed variation within and between sites of total mercury levels for these two species near the river and compared them to other locations. We predict total mercury levels to be higher in riparian compared to non-riparian sites and predict mercury levels to be higher at sites closer to a previously coal-fired powerplant. If significant mercury methylation can occur through detrital or terrestrial food chains, we expect specimens collected in Centralia to also have elevated mercury levels compared to agricultural sites.