News

Toxicity – biodiversity relationships unravelled

The production and use of chemicals is regulated by environmental legislation so as to protect the diversity of our surface waters. Until recently, however, it was impossible to predict the relationship between chemical toxicity and the diversity of aquatic communities, which hampered effective environmental conservation. Together with an international consortium, the laboratory of environmental toxicology (http://www.milieutox.ugent.be, UGent) developed the first theory to predict biodiversity along gradients of toxic stress. Combining this theory to data from polluted algal communities, the scientists reveal that the variability of toxicity tolerance in these communities is five to ten times higher between individuals from the same species than between individuals from different species. The results of this research also demonstrate that this 'within-species variability' is a buffer against species loss in ecosystems polluted with chemicals. These findings, which have been published in the nr 1-ranked ecology journal 'Ecology Letters', raise important concerns regarding the use of species-based tolerance data for environmental protection and explain ecosystem resistance during chemical spills.

An investigation of the inter-clonal variation of the interactive effects of cadmium and Microcystis aeruginosa on the reproductive performance of Daphnia magna

Stressors seldomly occur isolated in the environment. In a mixture, stressors can interact with each other. That might have profound adverse effects on the animals that live in the environment. Indeed, in mixture toxicity, one plus one does not always equals two. Imagine for instance the effect of throwing a mentos candy in coke (Youtube: MythBusters - Diet Coke and mentos). The effect of both combined is much larger than what you would expect. Such (synergistic) interactions between the metal cadmium and the cyanobacterium Microcystis are what De Coninck et al. (2013) studied in their most recent paper. Cyanobacteria are toxic blue-green algae that tend to increase in occurence due to climate change (for instance, Global Water Forum).

Development and validation of a quantitative structure–activity relationship for chronic narcosis to fish

Quantitative structure–activity relationship models (QSAR models) typically relate a set of predictor variables to the response variable. These models are useful tools in predictive ecotoxicology as the can be used to predict the (adverse) biological activity of a chemical (the response variable) based on the physico-chemical properties of the chemical (the predictor variables). As animal testing, and especially vertebrate testing, are generally strongly discouraged, the use of QSAR models offers an alternative. However, in ecotoxicology, QSAR models that describe the relationship between the physico-chemical properties of chemicals and their chronic toxicity to vertebrates are scarce. This lagoon in our knowledge is filled by the research described in our latest paper.

Too much pharmaceuticals in the river Maas

According to the latest report of the RIWA, a Belgian-Dutch organisation of water companies, too much pharmaceuticals were measured at 10% of the sampling points. Since Since we tap a lot of drinking water from the river, this finding is disturbing, say water companies. Although our drinking water is still perfectly safe, this elevated concentration of pharmaceuticals may have an adverse effect on organisms in the environment, such as femalized male fish. In another research project, performed in 2010 and involving our laboratory, which focussed on pharmaceuticals in the water at the ports of the North Sea, traces of seven pharmaceuticals were dicovered for the first time.

Read the full article as displayed in De Standaard of August 27th, 2013 (Dutch).