A FRESH-WATER BIOPROBE - PERIOSTRACUM OF THE ASIAN CLAM, CORBICULA-FLUMINEA (MULLER) COMBINED WITH LASER MICROPROBE MASS-SPECTROMETER

A freshwater bioprobe, combining the Asiatic Clam, Corbicula fluminea (Muller) and the laser microprobe mass spectrometer (LAMMA), can determine anthro-pogenic chemical contamination of freshwater systems. Laser generated mass spectra from the periostracal layers of clams contaminated with either a salt, potassium bromide, or an aromatic compound, phenol, produce distinctive mass spectral signatures that are different from uncontaminated clams. Uncontaminated clams have characteristic signatures with distinctive spectral peaks less than m/z 41; while exposed clams have many strong peaks well above this m/z. This freshwater bioprobe, using LAMMA to analyze the surface of clams, can be used as a screening tool for monitoring the water-treatment systems, for determining the source of contaminated baseflow and return flow discharge to streams, and for monitoring the water chemistry of a body of water. This system exploits the facility of using the shell instead of soft tissue with the LAMMA and has potential to detect anthropogenically-derived chemical stress.