The distribution of mercury in the Mersey estuary

The distributions of both dissolved and particulate mercury in the Mersey have been evaluated. A well-defined seaward increase of dissolved mercury concentrations was observed. Further offshore, much lower dissolved mercury concentrations, typical of unpolluted coastal waters, were recorded. Dissolved mercury is, however, rapidly removed from solution, presumably by scavenging and precipitation. Mercury-contaminated water discharged to the Manchester Ship Canal from the chlor-alkali plants at Runcorn and Ellesmere Port is periodically released to the estuary via the Weaver Sluices. Discrete dissolved mercury maxima are observed in the estuary adjacent to the point of release. A broad maximum in the particulate mercury distribution occurs in the middle estuary.