Multivariate landscape analysis of honey bee winter mortality in Wallonia, Belgium

The European honey bee species (Apis mellifera L.) is under increasing pressure from anthropogenic and other stressors. Winter mortality of entire colonies is generally attributed to biological, environmental, and management conditions. The rates of winter mortality can vary extremely from place to place. A landscape approach is used here to examine the dependency between spatially distributed winter mortality rates, environmental and biological conditions, and apiary management. The analysis was applied to data for the region of Wallonia in Belgium with winter mortality rates obtained from the European project EPILOBEE. Potential explanatory variables were spatially allocated based on GIS analysis, and subjected to binomial linear regression to identify the most predominant variables related to bee winter mortality. The results point to infestation with Varroa, the number of frost days, the potential flying hours, the connectivity of the natural landscape, and the use of plant protection products as most dominant causes for the region of Wallonia. The outcomes of this study will help focus beekeeping and environmental management to improve bee health and the effectiveness of apiary practices. The approach surpasses application to the problem of bee mortality and could be used to compare and rank the causes of other environmental problems by their significance, particularly when these are interdependent and spatially differentiated

Assessment of road run-off and domestic wastewater contribution to microplastic pollution in a densely populated area (Flanders, Belgium)

Plastics are omnipresent in our daily life. Unfortunately, the produced plastics will partly end up in the environment including aquatic ecosystems. People often refer to littering or illegal waste dumping as sources of plastic emission to the environment. However, daily-life sources could also, unknowingly, contribute considerably to the total microplastic pollution in the ecosystem. Hence, there is an urgent need to study these potential sources. In this research, two common sources, i.e. domestic wastewater and road run-off from tire and road wear particles, were studied in detail to quantify the relative contribution of both domestic sources towards microplastic pollution in freshwater ecosystems in Flanders, Belgium. This assessment shows that every person (in studied area) emits on average 1145 microplastics (25-1000 & mu;m) daily through domestic wastewater, resulting in a yearly discharge of 418,000 microplastic particles per person. The road run-off samples contained between 0.02 and 9.2 mg tire wear particles per litre per day, which corresponds to an emission of 10.8 mg tire wear particles per driven vehicle km. The gross and net emissions of both above mentioned microplastic sources were extrapolated to the whole Flanders region using an emission model. From the yearly gross microplastic pollution in the domestic wastewater, 623 kg (20%) will be discharged in the freshwater. The highest losses originated from the households that have a private drain or are not (yet) connected to an active wastewater treatment plant. In Flanders, the yearly net microplastic emission into the aquatic environment of tire wear particles is estimated to be 246 tonnes (38%), mainly from the direct run-off from the road surface. Based on the results, specific mitigation measures can be installed to reduce the emission of microplastics towards the freshwater ecosystem. Other sources should be quantified in a similar way for a more holistic strategy to counteract plastic pollution

Onderzoek naar verspreiding, effecten en risico’s van microplastics in het Vlaamse oppervlaktewater : kernrapport

Dit rapport stelt de resultaten voor van een eerste, breed-verkennende studie naar de microplastic waterverontreiniging in Vlaanderen. In deze studie werd de huidige situatie in de Vlaamse zoetwatermilieus geanalyseerd, verschillende bronnen werden gekarakteriseerd en de efficiëntie van de waterzuiveringsinstallaties werd onder de loep genomen. Op basis van deze resultaten werd een extrapolatie uitgevoerd op niveau van Vlaanderen met behulp van het Water Emissions Inventory Planning Support System (WEISS) model (uitgevoerd door VITO). De resultaten samengevat in dit rapport worden gekoppeld aan relevante beleidsadviezen en de identificatie van kennisleemten. Dit kernrapport geeft een brede analyse van de huidige microplastic concentraties in verschillende matrices (oa. oppervlaktewater, sediment, biota) in Vlaanderen. Sommige aspecten worden verder uitgelicht in de gekoppelde deelrapporten, waarmee dit kernrapport een onlosmakelijk geheel vormt

Microplastic contamination in Flanders : identification of sources, pathways and mitigation strategies

Plastic industry is a booming business but unfortunately, part of the produced plastics end up in the environment. Once in the environment, the plastic will fragment into small particles, called microplastics (MP, smaller than 5 mm). Despite large (inter)national research efforts, many questions remain unanswered, especially at a local or regional scale. Therefore, the aim of the current study was to explore the MP pollution in the freshwater environment in Flanders. This research processed and analysed 210 samples collected from eight different matrices distributed in the geographic region Flanders (Belgium). Plastics were identified using Fourier-transform infrared spectroscopy. It was evident that MP are omnipresent in the freshwater ecosystems of Flanders. One litre of surface water contained 0.48 MP particles (ranging between 0 and 4.8 MP per litre). The sediment of the waterways contained on average 2,990 MP particles per kg of dry weight sediment (ranging between 610 and 9,558 MP per kg). The risk of adverse effects of MP pollution for the Flemish waterways are low to negligible. The current research quantified the MP present in domestic waste water as one of the sources of MP pollution. Per litre of domestic waste water, 0.96 to 39.8 microplastic particles were found. In 83% of the households, the domestic waste water is being transported to an active waste water treatment plant (WWTP), which are able to remove 97.5% of the MP before discharged in the waterway. Another source of MP contamination in the environment are the microscopic rubber tire wear particles that are formed due to the friction between the tires and the road. Based on the run-off samples, an estimated emission of 10.8 mg tire wear particles per driven km was calculated. The emissions of both above mentioned sources were extrapolated to whole Flanders region area. From the yearly MP pollution in the domestic waste water, 623 kg of MP particles will end up in the aquatic environment. The highest losses originate from the households that are not connected to a WWTP. The yearly net emission of tire wear particles in Flanders is estimated to be 245,926 kg, a remarkably higher emission compared to the estimated MP emission from domestic waste water. In conclusion, this research was able to demonstrate that MP are ubiquitous in the Flemish environment, but this data offers some clear perspectives on mitigation measures to reduce MP emission to the freshwater ecosystem