A METHODOLOGY FOR THE ASSESSMENT OF ACCIDENTAL COPPER POLLUTION USINGTHE AQUATIC MOSS RHYNCHOSTEGIUM-RIPARIOIDES

Laboratory experiments using aquatic mosses were carried out in order to develop strategies for the monitoring of accidental metal discharge s into rivers. A flow-through system was used to simulate 24 different accidental discharges of Cu by combining 4 exposure intensities (42, 82, 178 and 342 mug L-1) and 6 durations (1, 6, 12, 24, 72 and 168 hou rs). Exposure to Cu was followed by a 10-day depuration phase. Uptake kinetics can be described by non linear equations. Most of the Cu accu mulation in the mosses occurred in the first 96 hours and reached an e quilibrium state within 168 hours. All depuration kinetics can be desc ribed by decreasing logarithmic equations. The extent of Cu release fr om the mosses depends on the maximum Cu levels reached at the end of t he uptake phase. Copper levels in the mosses during the depuration pha se reached an equilibrium state and remained higher than the initial l evel. Specific sampling strategies and calculations allow us to estima te both the mean aqueous Cu concentration during the discharge and the duration of exposure if the mosses are sampled before the aqueous Cu concentration starts to decrease. Retrospective assessment of the maxi mum Cu level reached in the mosses during the Cu discharge is also pos sible if the mosses are sampled during the first 10 days of the depura tion phase while the aqueous Cu concentration is returning to the back ground level.