Sensitivity to selected contaminants in a biological early warning system using 'Anodonta woodiana' (Mollusca)

Several early warning systems for the monitoring of water quality are based on the assessment of valve opening/closing in bivalves. Tests were conducted to assess the sensitivity of the mussel Anodonta woodiana , installed on the Mosselmonitor, to seven contaminants and evaluate the usefulness of these sensors for detecting pollution events in the Po River (Italy). Mussels were exposed for 30 min to increasing concentrations of chromium (range 0.01–5 mg/L); arsenic (range 0.05–2.5 mg/L); sodium dodecyl sulphate SDS (range 0.25–50 mg/L); phenol (range 0.1–100 mg/L); oxadiazon (range 0.001–5 mg/L); trichloroethylene (range 0.01–100 mg/L); and crude oil (range 0.5–50 mg/L). Treatment with the highest concentration of SDS elicited two types of alarm response. In a second set of tests, the bivalves were exposed for 6 h to a selected concentration of each chemical. Only SDS led to a dramatic alteration of valve opening, resulting in alarms. This system would have limited applications for monitoring drinking water influent. Keywords: bioindication, mussels, valve movement, toxicity test, toxic substance