PT Unknown
AU Kontchou Mr, J
TI Entry and Effects of Particle-bound Pollutants in Urban Freshwater Bodies
PD 07
PY 2022
DI 10.17185/duepublico/76655
LA en
AB Efforts to achieve a good status of most water bodies are continuously being hampered by poor sediment quality caused by the input of contaminated particles from anthropogenic sources. Most urban discharges such as stormwater and powdered activated carbon treated wastewater effluent contain particulate matter which harbours significant loads of contaminants. Entry of these particles in surface water bodies may result in chemical pollution of the sediment and adverse effects on benthic organisms. Therefore, the aim of the present thesis was to elucidate the fate of particle-bound contaminants in urban discharge on sediments of receiving freshwaters and the possible adverse effects on benthic biota. To this end, particles from stormwater discharges (separate sewer) and wastewater treatment plants (WWTPs) were investigated for their potential in degrading freshwater sediment and causing toxic effects on sediment-dwelling organisms. For the separate sewer pollution, two different catchments with stormwater basins were investigated (a predominant traffic catchment and a multipurpose land-use catchment). Studies were done with field-collected sediment and amphipod samples. Additionally, exposure experiments were performed in the laboratory with the endobenthic annelid Lumbriculus variegatus. Sediment and amphipod samples were analysed for their pollutant load followed by bioaccumulation and toxicity assessments in the laboratory with L. variegatus. Furthermore, the consensus-based sediment quality guideline (CBSQG) was applied to predict the toxic potential of sediments affected by stormwater discharges. For particles from WWTP, sediment toxicity experiments with L. variegatus were conducted with artificial sediment spiked with micropollutant loaded PAC from a WWTP. The present thesis recorded pollutants in sediments of stormwater receiving streams to occur above the natural background level. There was an increased accumulation of metals in sediment and biota downstream of the traffic stormwater basin outfall in the receiving stream while the multipurpose land-use catchment showed no increasing pattern downstream of the stormwater basin outfall in its studied stream. Bioaccumulation experiments revealed that L. variegatus took up stormwater pollutants from the sediment which in turn induced physiological responses in them. Although some particle-bound pollutants could escape retention in the stormwater basins and enter freshwater bodies, the investigated basins could still prevent receiving waters from a significant load of pollutants and the corresponding toxic effects. This was revealed by the high concentrations of pollutants and toxic potentials producing stronger physiological responses and lethal effects in the retention basin samples. For the studied WWTP micropollutant (MP) loaded particles, no effect on growth, reproduction and behaviour were found even with concentrations above environmental levels. Nonetheless, there was indication of possible adverse effects of these particles on benthic dweller if ingested after releasing the bound MP. Hence, the findings of this thesis further highlight the importance of upgrading prevention measures for anthropogenic-related particles that transport a considerable load of pollutants in freshwater bodies
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