UvA environmental chemists Steven Droge and Pim de Voogt are rewarded a research grant of €500,000 by CEFIC, the European Chemical Industry Council. The grant is intended for research on fish that is contaminated with cleaning agents.
In the next three years Droge and de Voogt will team up with scientists in Stockholm and Toronto for the development and validation of alternative methodologies for predicting the accumulation of surface active ingredients related from cleaning agents in fish.
Surface active agents (surfactants) are well known ingredients of washing powder, shampoo, soap, and fabric softener, but specific surfactants are also used in cosmetics, paints and lacquers, oil drilling and transportation, and even as antibiotics. Relatively high surfactant concentrations can reach the waste streams entering sewage treatment plants, after which small percentages can reach surface water ecosystems.
The environmental risk of chemicals is the ratio between the ‘minimal’ toxic effect concentration and the actual field concentration. Part of the environmental risk is the capacity of chemicals to accumulate in food webs, particularly in fish and top predators. The physical chemical properties of surfactants deviate from common organic contaminants like PCB and DDT, and for this reason current testing methods and risk models are not suited to adequately assess the environmental risk.
Also, the high numbers of fish that are required to test the accumulative properties of the wide diversity of surfactants, rather than predicting them, are costly and ethically undesirable. Because of the technical and analytical challenges surfactants pose, high quality reference data on accumulation factors in fish are scarce, hampering the development of improved models.
The research of Droge and De Voogt ties together several research lines that involved scientist have recently worked on regarding the modeling of fish uptake of contaminants with deviating properties. Currently, most model parameters are being derived from chemical structure-effect relationships and octanol-water partition coefficients, which both are inadequate for surfactants.
In this project, UvA scientists will derive relevant tissue-specific partition coefficients and metabolisation rate constants (with enzymatic liver extracts) using efficient in vitro studies. Stockholm University will perform a limited series of in vivo accumulation studies for several key surfactant structures. The Toronto scientists will use these input values to calibrate and validate the improved fish accumulation model.