Trends in heavy metals, polychlorinated biphenyls and toxicity from sediment cores of the inner River Thames estuary, London, UK.

River islands (Ait or Eyot) within the inner tidal Thames serve as unique recorders of current and historical estuarine chemical pollution. Sediment cores from Chiswick Ait were assessed for contamination using Microtox® solid phase bioassay, stable isotopes (δC, δN), heavy metals and polychlorinated biphenyls (PCBs). Microtox® classified these sediments as non-toxic to moderately toxic and bulk isotopes identified a change in organic input.