anchor: Because of the possible toxicity of thiosulfate to test organisms, a control lacking thiosulfate should be included in toxicity tests utilizing thiosulfate-dechlorinated water.
positive: Because of the possible toxicity of thiosulfate to test organisms, a control lacking thiosulfate should be included in toxicity tests utilizing thiosulfate-dechlorinated water.
negative: Because of the possible toxicity of thiosulfate to test organisms, a control lacking thiosulfate should not be included in toxicity tests utilizing thiosulfate-dechlorinated water.