Thousands of chemical compounds are used in every day products. When ef- fects of chemicals on the environmental are assessed, it is rarely considered that chemicals, ending up in the wastewater and potentially in the aquatic en- vironment, are mixed and that this potentially can change the toxicity of the chemicals. We here address the relation between single chemical exposure and mix exposure in sediment systems. A sediment exposure was performed with the two organic contaminants acetyl cedrene (AC) and triclosan (TCS). The gastropod Hydrobia ventrosa was exposed over a five day period to nominal concentrations of 1, 10, 50, 100 and 500 μg/g dw sed of AC/TCS. To examine the toxicity of the two chemicals in mixture, a new exposure was performed and the mix concentrations were calculated based on Toxic Units: 0, 0.125, 0.25, 0.5, 1, 2. Sediment and tissue extraction was performed on ASE and the concentrations were measured using GC-MS. Tissue concentrations were below detection limit, which could be due to the avoidance behavior of the snails, low bioavailability and/or biotransformation. In all treatments, the hig- her concentrations triggered an avoiding behavior (avoidance of sediment and reduction in feeding rate) of the snails, indicating an increase in the toxicity of AC/TCS with increasing concentrations. In mixture exposure avoidance be- havior was observed to a greater extent, compared to exposures with AC and TCS separately. Feeding rate was significantly reduced by 59-98% in all mixtu- re concentrations, AC concentrations of 1.870, 190.7, 418.4, 1715 μg AC/g dw sed and TCS concentrations of 462.3, 921.5, 3888 μg TCS/g dw sed compared to the control. This indicates a higher toxicity of AC and TCS when occuring in mixture than when added separately. This relation could, however, not be detected on mortality which was highest in single exposures of AC/TCS.
|Uddannelser||Miljøbiologi, (Bachelor/kandidatuddannelse) Bachelor el. kandidat|
|Udgivelsesdato||13 jun. 2014|
- Hydrobia ventrosa
- acetyl cedrene