Partitioning of organochlorines between water, particulate matter and some organisms in estuarine and marine systems of the Netherlands

• Published in: Netherlands journal of sea research 1986-08, Vol.20 (2), p.239-251
• Main Authors: Duursma, E.K., Nieuwenhuize, J., Van Liere, J.M., Hillebrand, M.T.J.
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Natural water pollution; Pollution; Seawaters, estuaries; Water treatment and pollution
• ISSN: 0077-7579
• DOI: 10.1016/0077-7579(86)90046-3

The distributions of organochlorines in estuarine and marine systems, and in particular those of the individual PCB components have been analysed for the partitioning of these substances between water, particulate matter (seston), plankton, worms, shellfish, fish and some birds. The K d concept, where K d is the distribution coefficient in ml·g −1 units, has been used to investigate the distribution ratio between solid substrates and water. Additionally, an attempt has been made to determine the regression coefficient of K ds with a polarity index of the individual PCB components. Since the octanol-water partition coefficient (log K ow) is significantly proportional to the IUPAC Numbers of these components, this K d-IUPAC Number regression has been carried out for samples from the Delta region, the North Sea and the Wadden Sea. For the latter two regions, existing concentrations from unpublished reports have been taken. Two major results have been obtained, while one important question remains to be answered: (i) Organochlorine (pesticides and ΣPCBs) concentrations in mussels can be successfully correlated to salinities of estuarine waters, if the sources of organochlorines are linked to the major fresh waters of the estuarine system. This correlation is independent of the seasonal changes in condition of these organisms by fat content, if the records is made for a period of two years. (ii) These results and those on K d determinations demonstrate for aquatic organisms a degree of consistency in the K d levels if concentrations in the organisms are calculated on fat basis. The K d range for ΣPCBs is 10 5–10 6, independent of the area of investigation. The same is true for seston with a range of K ds of 10 4–10 5. (iii) A very interesting question involves the K d-IUPAC Number regression coefficients and the value and sign (+ or −) of this coefficient. In general 60% of all correlations seem to be significant, but the different values and in particular the negative correlations are difficult to explain even when third-degree S-shape correlations are considered. A negative correlation implies a weaker adsorption of less-polar compounds (higher chlorinated PCBs with higher IUPAC Number), which cannot be explained by hydrophobic-hydrophylic reactions. An extended study on the true-dissolved organochlorines might be necessary to exclude errors which might be due to the methodology of filtration.