Alternative approaches can greatly reduce the number of fish used for acute toxicity testing.

Acute toxicity tests with algae, daphnids, and fish are required for the classification and environmental risk assessment of chemicals. The degree of risk is determined by the lowest of these acute toxicity values. Many ecotoxicological programs are seeking to reduce the numbers of fish used in acute toxicity testing.

Absorption of a mutagenic metabolite released from protein-bound residues of furazolidone.

The use of nitrofurans as veterinary drugs has been banned in the EU since 1993 due to doubts on the safety of the protein-bound residues of these drugs in edible products. Following treatment of pigs with the veterinary drug furazolidone free 3-amino-2-oxazolidinone (AOZ), the side-chain of the drug, could be detected in the blood in concentrations up to 0.3 μg/ml.