Using Chemcatcher® to investigate the potential for remobilization of sediment-bound hormone-disrupting chemicals
It has been well proven that endocrine-disrupting chemicals (EDCs) can accumulate in river sediments. However, less is known about the possible remobilisation of sediment-bound EDC as a result of floods, bioturbation or dredging.
A recent study, published in Elsevier’s Water Research journal focused on oestrogenic compounds accumulated in sediments along the German River Luppe – a “hotspot” for oestrogenic contamination. Both POCIS and Chemcatcher® passive sampling devices were used to determine whether sediment-bound oestrogenic compounds might become bioavailable under turbulent conditions.
Estrone (50%, E1 – illustrated above left) and nonylphenol (35%, NP – above right) were found to account for the majority of oestrogenic activity reported, being readily bioavailable at ecotoxicologically relevant concentrations.
As reported in previous studies, Chemcatcher® demonstrated higher sampling rates relative to POCIS, making it more favourable for monitoring over shorter time frames, during which flood events might occur. Non-linear uptake kinetics were observed for NP in POCIS.
The study also suggested that with Chemcatcher®, the uptake of the freely dissolved E1 and NP substances in the water was faster than the dissociation of the substance from the suspended sediment. However, the researchers noted that while this effect is important to consider in laboratory studies with a defined amount of sediment, it may be negligible under field conditions where the sediment acts as an infinite source. Overall, the study supported the usefulness of passive sampling devices in monitoring oestrogenic compounds in suspended sediment.