[A quality status report for the North Sea: International cooperation]

aceites bifenilos policlorados bioaccumulation cadena alimentaria calidad del agua carga contaminante charge polluante eutrophication eutrophisation fishing areas fishing operations food chains heavy metals huile international cooperation lutte antipollution mar del norte mer du nord metales pesados navire citerne north sea oils operaciones pesqueras pollutant load pollution control pollution des mers polychlorinated biphenyls sea pollution tanker ships water quality zonas de pesca