Lead-based game shot used in hunting near waters is considered a main reason for lead-poisoning of waterfowl and aquatic organisms, prompting discussion about alternatives. This study provides a first comparison of the leaching behavior and resulting ecotoxicological impacts of shot exposed to freshwater, comprising lead-based and alternative shots containing bismuth, copper, steel, tungsten, and zinc. Ecotoxicological effect assessment was based on the acute Daphnia magna 48 h toxicity test according to the EN ISO 6341:2012 guideline. Strong leaching of copper (up to 4.22 μmol/L) and zinc (up to 41.12 μmol/L) from three types of alternative game shot caused significantly increased immobilization rates of up to 100%. In contrast, even the highest leaching of lead did not significantly impair Daphnia mobility. Highest concentrations of dissolved metal ions only matched the declared main components of the respective shots in 3 out of 9 cases. These results demonstrate that metal release from alternative game shot is an underestimated ecotoxicological risk, particularly since release of copper and zinc from alternative shots was demonstrated to be more hazardous for aquatic biota than conventional lead shot. There is an urgent need of managing the use of shot ammunition near waterbodies based on realistic ecotoxicological risk assessments.

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Monitoring sublethal effects of pharmaceuticals on nontarget species in aquatic environments has become an important topic in ecotoxicology, yet few studies have been conducted concerning the effects of beta-blockers on aquatic organisms. The present study investigated the effects of the beta-blocker sotalol (SOT) at 3 environmentally relevant concentrations on life-history traits of the New Zealand mudsnail Potamopyrgus antipodarum. Based on the pharmacodynamic properties of SOT, the authors hypothesized reduced numbers of embryos in the brood pouches, decelerated growth of adult snails, and smaller size of neonates, but no effect on mortality rates of adults. Contrary to the hypothesis, the total number of embryos was significantly higher after 56 d of exposure at nominal concentrations of 0.05 µg/L and 1.0 µg/L by 107% and 73%, respectively. No differences in embryo numbers were observed at earlier time-points. Therefore, the mode of action seems to be an extension of the reproductive period rather than an increase of the embryo production. Furthermore, our results indicate a hormetic dose-response relationship, because no effects were observed at the highest test-concentration (6.5 µg/L). Mortality, growth of adult snails, and neonate sizes were not affected by the beta-blocker. Given the strong influence on reproduction, the effects of sublethal concentrations of SOT and other beta-blockers deserve better consideration in ecotoxicological risk assessment.

Long-term effect assessments in ecotoxicological investigations are important, yet there is a lack of suitable exposure systems for these experiments that can be used for riverine species. A cost-efficient miniature circulatory system was developed that was evaluated for its applicability in long-term exposures in 2 stream-dwelling species: brown trout (Salmo trutta) and an amphipod (Gammarus roeseli). In an egg-to-fry exposure of S. trutta, the toxicity of 2 reverse osmosis concentrates was investigated as examples. Control hatching rate of yolk sac fry was 75 ± 7% and thus complies with the Organisation for Economic Co-operation and Development validity criterion (≥66%). The reverse osmosis concentrates did not impair the hatching rate in any tested concentration. In G. roeseli, mortality rates remained below 20% during a 21-d cultivation, fulfilling the common validity criterion in ecotoxicological testing. Mortality was significantly lower when the species was fed with conditioned alder leaves instead of an artificial shrimp food. Finally, a toxicity test on G. roeseli using copper as the test substance revealed median lethal concentration (LC50) values of 156 μg/L after 96 h and 99 μg/L after 264 h, which is in line with literature findings using other accepted exposure units. In conclusion, the miniature circulatory system provides a novel and cost-efficient exposure system for long-term investigations on riverine species that may also be applicable for other species of fishes and macroinvertebrates. Environ Toxicol Chem 2016;35:2827-2833. © 2016 SETAC.