Metal bioavailability from sediments and effects on the macroinvertebrate community

This field based study investigates to which extent sediment-bound metals are bioavailable to different groups of aquatic invertebrates and what effect this will have on the macroinvertebrate community.
Moreover the role of different sediment- and environmental characteristics like Acid Volatile Sulfides (AVS), organic matter and Fe/Mn oxides on the speciation and bioavailability of metals will be examined.

Ultimately this project will try to get a better view on which fraction of the total environmental metal concentration will be potentional toxic for macroinvertebrates under different sediment characteristics and environmental conditions.

The study contains in order of performance:
* Selection, sampling and characterisation of sediment in several metal polluted freshwater rivers in Flanders (By measuring Total metal content, AVS/SEM content, Organic matter, grain size, iron/manganes oxides, carbonate & CEC content)
* Investigate the effect of sediment characteristics on the bioaccumulation in different groups of macroinvertebrates, this in relation with important metal binding sediment characteristics like AVS
* Investigate the effect of metal accumulation on the macroinvertebrate community (This by looking at diversity and biotic indices like Belgian Biotic Index, Multimetric Macroinvertebrate Index Flanders and Abundancy Biomass Comparison Method). Furthermore the use of metal accumulation as a predictor for macroinvertebrate community effects will be investigated.
* Study the effect of temporal and spatial variation on sediment characteristics and the relation with accumulation and community effects
* Study of the internal distribution and detoxification of metals in macroinvertebrate tissue by the use of sebcullular fractionation and metallothionein analysis
* Lab experiment to investigate the effect of environmental variables like pH, oxygen and temperature on sediment characteristics and the consequence on bioaccumulation of metals in macroinvertebrates