Ecotoxicological study of arsenic and lead contaminated soils in former orchards at the Hanford site,USA

The purpose of this study was to assess ecotoxicity of former orchard soils contaminated with lead arsenate pesticides at the Hanford Site in Washington state (USA). Surface soil, plant, and invertebrate samples were collected from 11 sites in former orchard areas. Mean (standard deviation [SD]) for As and Pb in soil were 39.5 (40.6) and 208 (142) mg/kg dry wt, respectively (n = 11). These concentrations exceeded Hanford background levels but were similar to orchard soils elsewhere. In our study, As and Pb soil concentrations were positively and significantly correlated (r = 0.87, Bonferroni P < 0.05). Speciation of total inorganic As in soil (n = 6) demonstrated that As+5 was the dominant form (>99%). Mean (SD) for As and Pb in cheatgrass were 3.9 (7.9) and 12.4 (20.0) mg/kg dry wt, respectively (n = 11), while mean (SD) for As and Pb in darkling beetles were 5.4 (2.6) and 3.9 (3.0) mg/kg dry wt, respectively (n = 8). Linear regressions were constructed to estimate soil to cheatgrass and soil to darkling beetle uptake for As and Pb. These were significant (Bonferroni P < 0.05) only for cheatgrass versus soil (As) and darkling beetle versus soil (Pb). Standardized lettuce seedling and earthworm bioassays were performed with a subset of soil samples (n = 6). No significant effects (P > 0.05) were observed in lettuce survival or growth nor in earthworm survival or sublethal effects. Based on these bioassays, unbounded no observed effect concentrations (NOECs) in soil for As and Pb were 128 and 390 mg/kg dry wt, respectively. However, our range of soil concentrations generally overlapped a set of ecotoxicological benchmarks reported in the literature. Given uncertainty and limited sampling related to our NOECs, as well as uncertainty in generic benchmarks from the literature, further study is needed to refine characterization of As and Pb ecotoxicity in former orchard soils at the Hanford Site. © 2011 Wiley Periodicals, Inc. Environ Toxicol 29: 10–20, 2014.     

Effects of acute exposure to acidified water on the behavioral response of fathead minnows, Pimephales promelas, to chemical feeding stimuli

Fathead minnows, Pimephales promelas, exposed to acidified water (pH = 6.0) for 72 h did not respond to a chemical stimulus that elicited a strong feeding response at higher pH levels. The lowest pH at which a statistically significant response occurred was 6.5. However, visually oriented feeding still occurred. These findings, evaluated in association with results obtained from other studies of pH effects on olfactory receptors, indicate that chemoreceptive processes were interfered with and that impaired chemoreception can occur at a relatively high pH. We suggest that food selection and intake could be seriously affected under natural conditions, thus compounding the effects of environmental acidification that ultimately cause reduced reproduction and elimination of fathead minnows from acidified lakes.The potential exists for the bioassay technique described in this study to be extensively used to assess effects of pollutants on the behavioral response of fishes to natural stimuli such as food odors, sex pheromones, and alarm substances from damaged skin.