RISICO · Risk Assessment of Surfactants in Coastal Environments

Final Activity Report Summary - RISICO (Risk Assessment of Surfactants in Coastal Environments)

The purpose of the RISICO project was to refine the ecological risk assessment of various classes of surfactants in coastal environment. The selected test compound was the anionic surfactant linear alkyl benzene sulfonate (LAS), one of the most common surfactants in the formulation of detergents and other cleaning products. Four main working areas were defined for the RISICO project: 1. bioavailability of surfactants in marine sediments 2. bioaccumulation of surfactants in marine organisms 3. biodegradation and ecotoxiciy of surfactants in marine environments 4. aerosolization of surfactants in coastal environments. We chose to fulfil the project obejctives by providing high quality training opportunities to four PhD students who were exposed to applied questions relevant to the surfactant industry. We developed collaboration between Procter and Gamble Eurocor Belgium, the Institute of Marine Sciences in Andalusia, Spain, the Institute for Risk Assessment Sciences of Utrecht University in the Netherlands, the Plant Bioengineering Department of the Free University of Brussels, Belgium and the International Atomic Energy Agency, Marine Environment Laboratory in Monaco. The sorption of the anionic surfactant LAS in marine sediments might influence the bioavailability of these compounds to benthic organisms. Our objective was to assess the relationship between the bioavailability of LAS with its free concentration in the pore water. In that case, the effect concentration in water-only exposure would be similar to the effect concentration in sediment pore water (EqP). Sorption studies were performed in several marine and estuarine sediments previously characterised with the model compound C12-2-LAS. We quantified the impact of the major factors affecting bioavailability of LAS in marine sediments, such as concentration, surface area, clay fraction and iron and aluminium oxide content. This was validated with spiked sediment bioassays with corophium volutator. Regarding the bioaccumulation of surfactants in marine organisms, our objective was to characterise kinetics of biological uptake and subsequent depuration of the anionic surfactant LAS for different contamination pathways, i.e. water and food. 14C12-LAS was used in a radioisotopic approach to measure the transfer and fate of LAS in selected marine species, including five marine microalgae, the Mediterranean mussel mytilus galloprovincialis and the fish sparus aurata. The bioconcentration factor (BCF) was smaller than 50 l kg-1 wet weight in mussel and fish and the sorption coefficient varied from 3,000 to 16000 l kg-1 dry weight in algae. LAS sorption and uptake processes appeared to be reversible both for desorption observed on algae and elimination on mussels and fish. The objective of the study of biodegradation and ecotoxicity of surfactants in marine environments was to assess the fate and effects of LAS in marine conditions. A biofilm was established by the ‘Centro de Investigación y Formación Pesquera y Acuicola’ (CIFPA) through colonisation of glass beads in an open flow through system of natural seawater in the Bay of Cadiz. In such a system, LAS was extensively mineralised, covering from 52 to 64 % 14CO2 production. After a 10 weeks’ experiment, 4 % of the radioactivity added to the system still remained in the water and was associated to LAS metabolites as observed on rad thin layer chromatography. When the tested temperature was reduced to 21, 16, 12 and 6 °C respectively the mineralisation extent decreased. However, the mineralisation extent was less affected by the temperature when using as inoculum bacteria originated from Sweden rather than from Spain. Indeed, at 6 °C the acclimated biofilm from Sweden was unexpectedly able to degrade up to 39 % LAS in 59 days, with the steady state still not being reached, as opposed to the acclimated biofilm originating from Spain, which resulted in less than 10 % conversion to CO2.

Data: CORDIS, © European Union