Relationships between ambient geochemistry, watershed land-use and trace metal concentrations in aquatic invertebrates living in stormwater treatmentponds

Stormwater treatment ponds receive elevated levels of metals from urban run off, but the effects of these pollutants on organisms residing in the ponds are unknown. We investigated the accumulation of Cu, Zn, and Pb by macroin vertebrates collected from stormwater treatment ponds in Maryland serving c ommercial, highway, residential and open-space watersheds, and determined w hether watershed land-use classification influences metal concentrations in macroinvertebrates. sediments, and water. Three types of invertebrate samp les were analyzed - molluscs. odonates. and composite. Zn concentrations in odonates from ponds draining watersheds with commercial development (mean = 113.82 mug g(-1)) were significantly higher than concentrations in the ot her land-use categories. Similarly, Cu levels in odonates from commercial p onds (mean = 27.12 mug g(-1)) were significantly higher than from highway ( mean = 20.23 mug g(-1)) and open space (mean = 17.79 mug g(-1)) ponds. Howe ver, metal concentrations in sediments and water did not differ significant ly among land-uses. The results suggest that despite the high variation in ambient metal concentrations within each land-use category, macroinvertebra tes in ponds serving commercial watersheds accumulate higher levels of Cu a nd Zn. The levels of Cu, Zn, and Pb in invertebrates from all ponds were le ss than dietary concentrations considered toxic to fish. Published by Elsev ier Science Ltd.