Nunny, R.S. & Smith, P.R.J. 1995 Existing Contaminant
Levels. Lyme Bay Environmental Survey. Vol. 15 Kerr-McGee.
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 µm
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.