An assessment of trends in European environmental data for mercury and chlorinated organic compounds in water and biota

European monitoring data for mercury and chlorinated organic compounds in fresh and saline water, biota and sediment have been examined for trends over the last 25 years. Information comprising over 15 000 records were collected from reports produced by European environmental agencies and regulatory agencies. Data sets larger than 5 consecutive years were summarised to derive annual averages before trend analysis. Little information was available to support claims for the quality of monitoring information or its validity for this or other. applications. Despite the variability of monitoring data, it was possible to identify statistically significant downward trends for mercury and many organochlorine compounds in both water and biota samples.