Reports collection of sediments and shellfish from eastern Lyme Bay (including Portland Harbour) and their analysis for trace hydrocarbons and metals. Generally low levels of total organic material were found. Total hydrocarbon (THC) and polycyclic aromatic hydrocarbon (PAH) concentrations in sediments (total sediment samples) were, in general, equally low. Lyme Bay concentrations ranged from 0.56 to 29 µg/g TCH, with a slight increase eastwards in concentrations. Highest concentrations were found in Weymouth Bay and, in particular, Portland Harbour (200 µg/g TCH). The elevated levels in the vicinity of Portland Bill are attributable to past spills of fuel oil (now degraded), contamination from lubricating oils, or fallout from the incomplete combustion of fossil fuels. These will have been derived from shipping activity and from discharges, runoff and fallout from the urban areas of Weymouth.

Sediment metals analysis (on the <90 &micro;m fraction) gave high concentrations of metals (copper, zinc, chromium, nickel, lead and arsenic) for the sample from Portland Harbour, but were not necessarily the highest encountered during the survey. The results suggested that sewage discharges were the source of metals in some areas of Lyme Bay.

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