Laboratory to field validation in an integrative assessment of an acid mine drainage-impacted watershed

An integrative assessment was conducted in the Puckett's Creek; watershed o f southwestern Virginia, USA, to investigate the environmental impacts of a cid mine drainage (AMD) inputs. Twenty-one sampling stations were categoriz ed into groups based on five degrees of AMD input: (1) none, (2) intermitte nt acidic/circum-neutral AMD, (3) continuous acidic AMD, (4) continuous cir cum-neutral AMD, and (5) receiving system stations with at least two levels of dilution. Bioassessment techniques included water/sediment chemistry, b enthic macroinvertebrate sampling, laboratory acute water column toxicity t esting, laboratory chronic sediment toxicity testing, and in situ toxicity testing with Asian clams (Corbicula fluminea [Muller]). Group 3 stations ha d significantly altered water chemistry (low pH, high conductivity, and hig h water column metals) relative to the other groups and significantly highe r sediment iron concentrations. Both group 3 and group 4 stations had signi ficantly decreased ephemeropteraplecoptera-trichoptera richness and percent ephemeroptera abundance relative to unimpacted stations. Group 3 stations also had decreased total taxon richness. Water column toxicity testing was sensitive to AMD impacts, with samples from group 3 stations being signific antly more toxic than those from groups 2 and 4, which in turn were more to xic than those from groups 1 and 5. Similar results were observed for in si tu toxicity testing. No differences in sediment toxicity test survival and impairment results were observed among the station groups. Stepwise multipl e linear regression and simple bivariate correlation analyses were used to select parameters for use in an ecotoxicologic rating system, which was suc cessful in differentiating between two levels of environmental impact relat ive to stations receiving no AMD input.