Distribution, Fate and Bioaccumulation of Selected Herbicides in the Sacca di Goro Lagoon: Coupled Experimental and Modeling Approaches

Anthropogenic release of chemical contaminants, in particular pesticides, originating from agricultural area of Pianura Padana, significantly impact coastal lagoon ecosystems of the Po River Delta (Galassi et al., 2000; Riparbelli et al., 1996; Baldi et al., 1991; Coppi et al., 1999; Della Vedova et al., 1996; Brown et al., 1996). In particular the Sacca di Goro lagoon, which is one of the most important acquacultural systems in Italy,fish and shellfish production (especially Tapes philippinarum farming) provides work, directly or indirectly, for five thousand people. The Main objective of this study is to provide a useful evaluation tool of Tapes philippinarum exposure to pesticides, especially herbicides, through experimental data and the implementation, development and validation of a pesticide bioaccumulation model. The study has two components: experimental measurement of the levels of contaminants in various environmental compartments as the first step in assessing the exposure, and development of a 3D modelling approach to take into account temporal and spatial variations, which are characteristic of coastal lagoons. The pesticides that are included in this survey have been chosen on basis of several criteria: presence in the study area (literature and experimental data), data volume of sales and presence on the list of priority hazardous substances for the European Community (directive 2000/60/CEE, decision n. 2455/2001/CE). Reference quality standard limits for these substances have been established by the Italian law (Decreto 6 novembre 2003, n. 367, Appendix 2), following the directive 2000/60/CEE, with reference to decision n. 2455/2001/CEE. The model consists of a dynamic mass balance that includes a time-variable chemical transport and fate model for calculating herbicide concentrations in the water column as well as and in sediments based on Farley et al., (1999) model for PCBs in Hudson river and its estuary. In a second step, this model has been coupled with the ecological model already developed for Sacca di Goro (Zaldívar et al., 2003) to analyze the bioaccumulation of herbicides in the food web chain and compare with available experimental results. The bioaccumulation model is based on Thomann, (1989) model of organic chemical distribution in acquatic food chains and Del Vento and Dachs, (2002) model of uptake dynamics of POPs by bacteria and phytoplankton. The present study will provide a quantification of micropollulants fate in a shallow water ecosystem and an estimation of interaction between high-density clam farming and contaminant bioavailability. This project has been developed at the Institute for Environment and Sustainability of the Joint Research Centre (Ispra, VA) in collaboration with the Department of Environmental Science at Parma University.

CARAFA Roberta; 

2007-01-16

JRC35924