Fungiciden

Organic chemicals can contribute to local and regional losses of freshwater biodiversity and ecosystem services. However, their overall relevance regarding larger spatial scales remains unknown. Here, we present, to our knowledge, the first risk assessment of organic chemicals on the continental scale comprising 4,000 European monitoring sites. Organic chemicals were likely to exert acute lethal and chronic long-term effects on sensitive fish, invertebrate, or algae species in 14% and 42% of the sites, respectively. Of the 223 chemicals monitored, pesticides, tributyltin, polycyclic aromatic hydrocarbons, and brominated flame retardants were the major contributors to the chemical risk. Their presence was related to agricultural and urban areas in the upstream catchment. The risk of potential acute lethal and chronic long-term effects increased with the number of ecotoxicologically relevant chemicals analyzed at each site. As most monitoring programs considered in this study only included a subset of these chemicals, our assessment likely underestimates the actual risk. Increasing chemical risk was associated with deterioration in the quality status of fish and invertebrate communities. Our results clearly indicate that chemical pollution is a large-scale environmental problem and requires far-reaching, holistic mitigation measures to preserve and restore ecosystem health.

Flüsse und Seen auf dem Kontinent sind offenbar stärker mit Chemie belastet als weitgehend angenommen. Eine Studie im Fachmagazin "PNAS" macht das Ausmaß klar. Die große Bedrohung für Wasserlebewesen: Pharmazeutika und Pestizide. Viele regen sich über die angebliche Regelwut der Europäischen Union auf. Der Ökotoxikologe Dr. Werner Brack vom Helmholtz-Zentrum für Umweltforschung in Leipzig sieht aber durchaus Vorteile. Seit dem Jahr 2000 verpflichtet die Europäische Wasserrahmenrichtlinie die Mitgliedsstaaten zur Messung und Dokumentation der Chemikalienkonzentrationen in den Flüssen. "Wir konnten jetzt zum ersten Mal auf diese Datenbanken zugreifen sozusagen und konnten uns wirklich auf einer europäischen Ebene angucken, welchen Einfluss, welches Risiko von Chemikalien auf die Gewässerqualität ausgeht."

Most environmental protection issues concern the often chronic exposure of large populations to low doses of chemical toxins and ionizing radiation. However, measuring the effects of low doses on populations exposed over long time periods is highly problematic. Politically driven opinions often tend to take the place of science. Part of the problem is that epidemiology is a weak tool when the level of exposure is low. High background levels of exposure, genetic diversity, and exposure uncertainties all contribute to “noise” and make dose-response relationships difficult to define. Uncertainty feeds anxiety, leading to polarized politics. This review looks at the promise of molecular technologies for identifying the effects of low doses of radiation and identifies some of the issues involved in defining risk after low-dose exposures. While the main pollutant discussed in this article is ionizing radiation, the analysis could apply equally well to other toxic exposures or to combined radiation and chemical pollutants.

We have recently been surveying what chemicals the local farmers in East Sussex use each year. Chemicals applied to two fairly typical fields, one with winter oilseed rape, one with winter wheat, in a single growing season (2012/13). I should stress that these are perfectly normal farms; not especially intensive, situated on the edge of the South Downs, an area of gentle hills, hedgerows and wooded valleys. Beautiful, rural England; Constable would have liked it here. But let’s look at it from a bee’s perspective, focussing on the oilseed rape, since this is a crop they will feed on when it flowers: firstly, the crop is sown in late summer with a seed dressing containing the insecticide thiamethoxam. This is a systemic neonicotinoid, with exceedingly high toxicity to bees. We know it is taken up by the plant, and that detectable levels will be in the nectar and pollen gathered by bees in the following spring. In November, despite the supposed protection of the neonicotinoid, the crop is sprayed with another insecticide, the charmingly named Gandalf. Gandalf contains beta-cyfluthrin, a pyrethroid. Pyrethroids are highly toxic to bees and other insects, but there should be no bees about in November so that is probably OK. The following May, when it is flowering, the crop is sprayed with another pyrethroid, alpha-cypermethrin. Less than three weeks later, the crop is blitzed with three more pyrethroids, all mixed together, a real belt-and-braces approach. Why use one when three will do? The crop is still flowering at this point (it was a late year), and would be covered in foraging bumblebees and other pollinators. In between, the crop is also treated with a barrage of herbicides, fungicides, molluscicides and fertilizers – 22 different chemicals in total.