Includes use of aerobic or anaerobic respirometers to assess oxygen uptake or gas production from reactors that contain an active biomass culture and various amounts of wastewater or chemical.The response of the culture to the chemical dose gives an indication of toxic impact. The data can be used to determine LC50 or other measures of toxicity plus give an indication of the maximum amount of wastewater or chemical that can be added to a treatment plant without causing failure. Prices are by quotation only.