Contaminant release and risks during environmental dredging projects
Supervisor: Johhny Teuchies, Lieven Bervoets, Elvio Amato
In several streams in Flanders large amounts of metals have been discharge last decades. The contaminant influx is currently limited, but large amounts of metals accumulated in the sediments. For example, very high cadmium and arsenic concentrations are found in the sediments of the Winterbeek. Several remediation projects are planned. Starting early 2017, a certain stretch of the Winterbeek will be remediated by hydraulic dredging. Sediments will be deposited on the banks, drained for 3 months and then removed and disposed. This remediation process is not without risk. In this master thesis the release of metals during dredging and draining will be investigated. Samples of the surface water, sediment and pore water in combination with bioaccumulation by transplanted invertebrates and measurements with passive samplers will give insight in the metal release and can be used to plan future remediation projects.)
Human health risk of urban farming
Supervisors: Lieven Bervoets, Johnny Teuchies
In the framework of sustainability, urban farming is considered promising in terms of local production, reduction of food miles, education, adding green to the cities or eating fresh food. Also community supported agriculture or farming close to the consumers is becoming popular. However, in large cities or (historical) industrial areas, the risk of contaminant uptake in the food, through atmospheric deposition or soil pollution is larger. In this master thesis the accumulation of metals in different crops and different locations will be investigated. The thesis can be extended with laboratory studies investigating the uptake patters. Also in-situ experiments to test different soil additives which can decrease metal uptake can be included.
Can we use lead slags in river embankment projects: environmental impact study
Supervisors: Johnny Teuchies; Lieven Bervoets
Metal slags are a waste product from the metallurgical or recycling processing and frequently used as armour stones to stabilize riverbanks or coasts. However, leaching from slags may be a source of hazardous metals towards the aquatic environment. In the Scheldt estuary (Belgium) tons of monolithic lead slags are used to protect and strengthen its banks. The environmental impact of the use of lead slags in river embankments is still unclear. In this master thesis we will setup laboratory leaching experiments, measure bioaccumulation of metals in different aquatic species in combination with in situ measurements (biota and sediments) in order to perform an impact assessment of the use of the slags in the Scheldt estuary.
Evaluation of the performance of a multi-contaminant passive sampler for water quality monitoring
Supervisors: Elvio Amato, Ronny Blust
The Water Framework Directive establishes a regulatory framework for community action in the field of the European (surface) water policy. The directive identifies a range of pollutants for which environmental quality standards are set and concentrations need to be periodically monitored. Current monitoring approaches often rely on spot sampling which provide one-point-in-time measurements that do not account for pollutants fluctuations commonly observed in the environment. In addition, some pollutants are present at very low concentrations for which the use of biomonitors is required, due to their ability to accumulate pollutants overtime. However, monitoring programs based on the use of biomonitors require reference populations or laboratory cultures that have to be maintained, and bioaccumulation in deployed organisms may differ from that of resident biota due to acclimation issues and different exposure conditions. A viable alternative to spot sampling and biomonitoring is offered by passive sampling. This novel approach involves the use of in-situ devices which continuously accumulate pollutants present in the water during the deployment time, thus providing time-averaged concentrations which account for pollutants fluctuations and are expected to be more representative of organism exposures. The accumulation of compounds in the passive sampler matrices is also sensitive to the environmental conditions and chemical speciation of the compounds and hence also their bioavailability. Through the comparison between passive sampler measurements and ecosystem evaluations (e.g. bioaccumulation, biodiversity, richness, abundance) conducted in targeted locations in Flanders, this study aims to test the applicability of passive sampling for water quality monitoring, and to derive passive sampler-based quality standards which are expected to more closely represent ecosystems health.
Passive samplers in wastewater – An innovative approach for monitoring new psychoactive substances
Supervisors: Elvio Amato, Ronny Blust
Contaminant concentrations in aquatic environments are frequently associated with seasonal, weekly and daily fluctuations. Traditional methods such as sample grabbing provide one-point-in-time measurements that do not often adequately represent such fluctuations, and may result in inaccurate estimates of contaminant concentrations in waters. Automatic samplers are often used to overcome these issues, yet with the inconvenient of being bulky and requiring power connection, thus limiting their deployment. Passive sampling techniques allow the measurement of a wide range of substances in a time-averaged manner. These emerging techniques offer a range of advantages over traditional methods, including less labor intensive processes, more cost-effective procedures, lower detection limits, and, most importantly, provide time-averaged concentrations, which are expected to be more representative of real environmental concentrations. Many contaminants, such as illicit drug residues in wastewater, show patterns associated with substance use and population dynamics. This project aims to evaluate the performance of the diffusive gradients in thin films (DGT) passive sampler for monitoring new psychoactive substances (NPS). Also referred to as “designer drugs”, these substances mimic the effects of conventional drugs (e.g., cocaine, amphetamine, ecstasy) and are generally not listed among the prohibited substances. Synthetic cathinones (e.g., methylone), synthetic cannabinoids (e.g., JHW-018) and piperazines (e.g., benzylpiperazine) are among the major classes of NPS. The ever growing number of available molecules, low dosages and limited prevalence of use of each individual substance result in low concentrations in wastewater, making it difficult to monitor their consumption using conventional sampling techniques. The evaluation of the DGT performance for measuring NPS concentrations in wastewaters will be based on the comparison with on-site composite flow-proportional sampling. In addition to providing a more robust and cost-effective method to measure levels of NPS in wastewater, this study will significantly contribute to the further development of wastewater-based epidemiology (WBE). The latter discipline aims at using levels of chemicals measured in wastewater (e.g., illicit drugs, pharmaceuticals, emerging contaminants, disease biomarkers) as indicators of the overall health status of entire populations. Through the selective deployment of sampling devices, the developed approach will allow improving both the spatial and temporal resolution of the acquired data.