Andrew J. Wigginton

Toxicity of cadmium to six species in two genera of crayfish and the effect of cadmium on molting success

Nine acute (96-h) toxicity tests were conducted on six species of crayfish (Cambaridae). Six tests focused on adults, and three tests examined juveniles. Lethal concentration to 50% of a population (LC50) and lethal concentration to 10% of a population (LC10) values, respectively, for the adults of individual test species were as follows: Orconectes juvenilis, 2.44 and 0.623 mg Cd/L; Orconectes placidus, 0.487 and 0.092 mg Cd/L; Orconectes virilis, 3.30 and 0.947 mg Cd/L; Procambarus acutus, 0.368 and 0.048 mg Cd/L; Procambarus alleni, 3.07 and 0.386 mg Cd/L; and Procambarus clarkii, 2.66 and 0.486 mg Cd/L. The Orconectes LC50 genus mean acute value (GMAV) was 1.57 mg Cd/L, whereas the LC50 GMAV for Procambarus was 1.44 mg Cd/L. The LC10 GMAVs were 0.379 and 0.208 mg Cd/L, respectively. Family mean acute values (FMAVs) also were calculated for the Cambaridae using all species data (LC50, 1.51 mg Cd/L; LC10, 0.281 mg Cd/L). For tests with juvenile crayfish, the LC50 and LC10 values, respectively, were as follows: O. juvenilis, 0.060 and 0.014 mg Cd/L; O. placidus, 0.037 and 0.002 mg Cd/L; and P. clarkii, 0.624 and 0.283 mg Cd/L. The GMAVs were calculated for juvenile Orconectes (LC50, 0.047 mg Cd/L; LC10, 0.005 mg Cd/L). Additionally, FMAVs were calculated for juvenile crayfish (LC50, 0.111 mg Cd/L; LC10, 0.020 mg Cd/L). Crayfish sensitivity to Cd varied by a factor of nine among species tested as adults and by a factor of 17 among species tested as juveniles. Molting was a sensitive life stage for crayfish. Most individuals that molted shortly before or during exposure to Cd died, whereas all controls that molted in the adult assays survived. Because molting is a sensitive, recurring life-cycle event, molting individuals should be included in toxicological analysis despite some contrary recommendations.

Assessing the Impacts of Coal Waste on Residential Wells in the Appalachian Region of the Big Sandy Watershed, Kentucky and West Virginia: An Exploratory Investigation

Abstract This paper examined issues surrounding coal waste and its potential impacts on residential private wells by reviewing the existing literature to identify the possible issues and parameters associated with coal waste and its possible effects on private wells. Using well water data from the Big Sandy Region of Kentucky and West Virginia (n = 42), drinking water quality was examined using standard heavy metal parameters associated with coal waste: arsenic, cadmium, chromium, iron, lead, manganese, zinc, and sulfate. Findings showed significantly more wells in sub-watersheds with coal waste impoundments with iron levels above secondary drinking water standards. A review of similar wells from the Kentucky Groundwater Database Repository showed a similar trend. This pattern warranted further study of Fe as a possible coal slurry waste marker. Other general findings revealed high concentrations of manganese, lead, and arsenic across our sampling of cases. Levels of these metals were high in Appalachian rock, so linking their levels to coal mining is problematic. Overall, findings suggested that residential well water in the coal mining area of the Big Sandy region of Appalachia may be of variable and sometimes unhealthy quality.