Acute and Chronic Toxicity

Abstract

Ecotoxicology is the study of the effects of poisons on ecological systems or components thereof. Ecosystems include individuals, populations, communities, and their abiotic environment. Acute toxicity is manifested over a short time period most often as mortality. Chronic toxicity develops over longer periods of time with measured endpoints such as fecundity, depressed growth rates, or changes in organism behavior or physiology. Ecotoxicological methods relevant to acute and chronic toxicity range in scale from tightly controlled laboratory assays through simplified ecosystems experiments to natural system and watershed studies. The ultimate goal of all toxicity testing is to provide data used to establish biologically safe concentrations for toxicants. Environmental regulation in the United States required the establishment of water quality criteria for select contaminants. The National Pollutant Discharge Elimination System is a water quality-based permitting system that regulates toxicity in effluents. Total maximum daily load development is an effort to apportion an acceptable level of pollution in surface waters to all contributors at a watershed scale. Toxicity identification methods have been developed to identify causative contaminant(s) when toxicity is observed in environmental samples. Finally, real-time whole organism biomonitoring is a viable tool for future acute and chronic toxicity monitoring in surface waters.