Distribution of chlorinated organic pollutants in harbor sediments of livorno (Italy): A multivariate approach to evaluate dredging sediments

Dredging is a very important procedure for harbor management. In Italy the guidelines for the offshore dumping of dredged materials are issued by the Ministry of Environment. They described a few steps of dredging activities, such as the sampling strategy, but do not deal with limits or guide-values for the chemical, physical and biological composition of the resulting sed iments. The quality of dredged materials is mainly dependent on the presenc e of inorganic and organic pollutants. In particular, polychlorinated biphe nyls (PCBs) and organo-chlorinated pesticides are seen as a high priority i n marine environment by international organizations because of their persis tence, toxicity and bioaccumulation capacity. In this article the presence of some PCBs and organo-chlorinated pesticides in sediment samples collecte d from the harbor of Livorno (Northern Tyrrhenian Sea) was investigated. Th e concentration of HCHs, Aldrin, Chlordanes, DDEs, DDTs, and PCBs in 12 rep resentative sites ranged between <1 mug kg(-1) and 95, 19, 32, 35, 107, and 111 mug kg(-1), respectively. The application of univariate and multivaria te statistical techniques, such as linear regression analysis and principal component analysis, to the experimental data showed a different distributi on of PCBs in the two sediment layers. On the contrary, the vertical distri bution of the other investigated pollutants was more homogeneous and affect ed by random variability. The multivariate approach was an important tool t o establish more rational criteria for the management of dredged materials.