Hydrocarbons and organochlorines in common mussels from the Kattegat and the belts and their relation to condition indices

The pollution loads by hydrocarbons and some organochlorines have been investigated in common mussels (Mytilus edulis L.) from the Inner Danish Waters. The ranges of pollutant concentrations were 7.5–108 μg g−1 wet wt for paraffin-naphthene(p-n-)-hydrocarbons, 10–111 ng g−1 wet wt (Σ14 PAH) for polyaromatic hydrocarbons, 3–328 ng g−1 wet wt (Σ7 chlorobiphenyl) for polychlorinated biphenyls, 2.4–67 ng g−1 wet wt for ΣDDT, 0.3-3.1 ng g−1 wet wt for α-HCH, 0.6–7.4 ng g−1 wet wt for γ-HCH and 0.05-0.74 ng g−1 wet wt for HCB. An interpretation of the physiological parameter, the condition index (measured as the ratio of dry weight of soft tissue to (shell length)3 and ‘normalized’ with respect to shell length) in relation to the lipid content showed a good correlation (r = 0.76, p = 0.0001). The condition index showed a significant negative correlation with the polyaromatic hydrocarbons (Σ14 PAH, r = −0.48, p = 0.01) and a weaker negative correlation with the p-n-hydrocarbons (r = −0.36, p = 0.08).