A workflow to investigate the impacts of weathered multi-walled carbon nanotubes to the mud snail Lymnaea stagnalis

Environmental Science and Pollution Research - Although the development and application of nanomaterials is a growing industry, little data is available on the ecotoxicological effects on aquatic...     

Erfahrungen des Umweltbundesamtes mit der EU-Biozid-Richtlinie

Biocides are active substances and products which are intended to destroy (…) any harmful organism by chemical or biological means. Typical applications are for instance wood preservatives, antifouling products or disinfectants. In the European Union the use of biocidal products is regulated since 1998 by the Biocidal Product Directive 98/8/EG (BPD). The BPD was transposed into German law in 2001 by the “Biozid-Gesetz”. The Federal Environment Agency is responsible for the environmental risk assessment of biocidal active substances and products under the “Biozid-Gesetz” in Germany. The European Commission has to evaluate the BPD seven years after endorsement and if necessary, has to submit a proposal for the revision of the directive. It is expected that the European Commission will publish soon a review of the enforcement of the BPD together with suggestions for the revision of the directive. In this article the German Federal Environment Agency summarises suggestions for the revision of the BPD based on its ten years experience with the directive: The scope of the BPD needs an exact clarification of borderlines in order to avoid confusion with other legislation. Food and feeding stuff together with natural products like lavender branches and cedar wood, which are used as attracting or repellent agents, have to be excluded from the scope of the BPD. Special data requirements for natural oils and pheromones should be developed to take the complex composition of these substances into account. The advantages of a centralised and decentralised authorisation procedure are discussed for biocidal products in special product types. Furthermore we stipulate that biocidal active substances which are nano particles are treated as separate active substances with own identities. Due to animal welfare reasons it should be obligatory to share data from vertebrate animal studies as it is already mandatory under the REACH regulation. The import of articles treated with biocidal active substances into the European market should only be allowed, if the active substance is approved for their biocidal use within the EU. Finally we suggest to implement an obligation to report the market shares or consumption rates of biocidal active substances and products. Together with procedural simplifications and adaptation in the scope of the directive, changes of the data requirements will be the key issues during the revision of the BPD. Most important, these changes should not reduce but ideally increase the level of protection for human health and the environment.     

Impact of weathered multi-walled carbon nanotubes on the epithelial cells of the intestinal tract in the freshwater grazers Lymnaea stagnalis and Rhithrogena semicolorata

Freshwater grazers are suitable organisms to investigate the fate of environmental pollutants, such as weathered multi-walled carbon nanotubes (wMWCNTs). One key process is the uptake of ingested materials into digestive or absorptive cells. To address this, we investigated the localization of wMWCNTs in the intestinal tracts of the mud snail Lymnaea stagnalis (L. stagnalis) and the mayfly Rhithrogena semicolorata (R. semicolorata). In L. stagnalis, bundles of wMWCNTs could be detected in the midgut lumen, whereas only single wMWCNTs could be detected in the lumina of the digestive gland. Intracellular uptake of wMWCNTs was detected by transmission electron microscopy (TEM) but was restricted to the cells of the digestive gland. In larvae of R. semicolorata, irritations of the microvilli and damages in the apical parts of the epithelial gut cells were detected after feeding with 1 to 10 mg/L wMWCNTs. In both models, we detected fibrillar structures in close association with the epithelial cells that formed peritrophic membranes (PMs). The PM may cause a reduced transmission of wMWCNT bundles into the epithelium by forming a filter barrier and potentially protecting the cells from the wMWCNTs. As a result, the uptake of wMWCNTs into cells is rare in mud snails and may not occur at all in mayfly larvae. In addition, we monitor physiological markers such as levels of glycogen or triglycerides and the RNA/DNA ratio. This ratio was significantly affected in L. stagnalis after 24 days with 10 mg/L wMWCNTs, but not in R. semicolorata after 28 days and 10 mg/L wMWCNTs. However, significant effects on the energy status of R. semicolorata were analysed after 28 days of exposure to 1 mg/L wMWCNTs. Furthermore, we observed a significant reduction of phagosomes per enterocyte cell in mayfly larvae at a concentration of 10 mg/L wMWCNTs (p?<?0.01).