Comparison of results of Mussel Watch Programs of the United States and France with Worldwide Mussel Watch Studies

As part of the Global Ocean Observing System (GOOS), the National Oceanic and Atmospheric Administration (NOAA) National Status and Trends (NS&T) Program compiled the World Mussel Watch (WMW) data base with results from the analyses of marine or estuarine mussels or oysters as far back in time as possible. Here we compare WMW data with results from two long-term Mussel Watch Programs, the Réseau National dʹObservation de la Qualité du Mulieu Marin (RNO) Mussel Watch in France and NS&T Program in the United States. The medians and 85th percentiles for Cr, Ni, Cu, Zn, As, Se, Ag, Cd, Hg and Pb in mussels and oysters were calculated for the WMW, NS&T and RNO Mussel Watch programs. While there was generally good agreement for medians among all three data sets, the upper ends of the WMW concentrations tend to be higher than their NS&T and RNO counterparts. This probably reflects the fact that the latter two programs emphasize collection of mollusks at representative sites rather than within small areas of extreme contamination such as near waste discharges.