Suchergebnisse

Abstract

Background
Information on pollen dispersal is essential for the risk assessment and management of genetically modified organisms (GMOs) such as Bt maize. We analyzed data on maize pollen deposition at 216 sites in Germany, Switzerland, and Belgium from 2001 to 2010. All data were collected using the same standardized sampling method. The distances between sampling site and the nearest maize field ranged from within the field to 4.45 km.


Results
Maize pollen deposition was negatively correlated with distance from the nearest pollen source. The highest pollen deposition was within the field, but depositions of several thousand pollen grains per square meter were recorded over the kilometer range. A power function model most accurately described the relationship between deposition and distance from the nearest pollen source, rather than the exponential model currently used in EU risk assessment and management, which underestimates exposure for distances greater than 10 m. Regression analysis confirmed the high significance of the power relationship. The large variation in pollen deposition at a given distance reflected the influences of wind direction and other meteorological and site conditions. Plausible variations of single values and the predicted mean pollen count at a given distance were expressed by confidence intervals.


Conclusions
The model described here allows estimations of pollen deposition in relation to distance from the nearest field; therefore, it will be valuable for the risk assessment and management of GMOs. Our results indicate that buffer zones in the kilometer range are required to prevent harmful exposure of non-target organisms to GMOs.

Abstract
Background
For market approval of genetically modified plants (GMPs), the evaluation of agronomic and phenotypic plant traits is a standard requirement and part of the comparative assessment of the GMP and its conventional counterpart. This comparative assessment is a starting point for environmental risk assessment (ERA) and should inform all areas of risk. We scrutinize frequently used approaches to characterize GMPs in EU market applications and discuss their usefulness for drawing conclusions on risks related to the plant's ability to survive, persist or become invasive.

Results
Our analysis shows that the agronomic and phenotypic characterization of GMPs, although based on guidelines, is confined to plant traits and test designs that are relevant for the quality control and agronomic performance of genetically modified (GM) crops. We provide evidence of how methodological approaches frequently applied during the agronomic and phenotypic characterization of the GMP could be improved and complemented to better inform on potential phenotypic changes relevant to assessing environmental risks. These approaches refer to (i) the assessment of the survival of GM seeds and plants (e.g., volunteers); (ii) the consideration of environmental exposure and (iii) improved methodological approaches for the assessment of biotic and abiotic stress responses for GMPs.

Conclusions
The comparative assessment of agronomic and phenotypic plant traits currently does not provide suitable data to draw conclusions on environmental risks relating to the persistence and invasiveness of the GMP. Ecologically more realistic assessments should be part of the phenotypic characterization of GMPs and need guidance and decision criteria to be implemented in ERA. This is of considerable importance, as new genomic techniques are expected to increase the diversity and complexity of GM plants and traits, particularly stress tolerance, which may affect the survival of GMPs in the environment.

Abstract
The aquatic Environmental Risk Assessment (ERA) for pesticides relies on standardized experimental protocols focusing on exposure via the water phase or the sediment. Systemic pesticides (e.g., neonicotinoids) or pesticides produced in transgenic plants (e.g., Bt proteins) can be introduced into aquatic ecosystems as part of plant residues. Consequently, they may be taken up by organisms as part of their diet. Here, we analyzed (i) whether standardized aquatic ecotoxicological test guidelines consider an exposure route via food and (ii) whether these tests can be easily modified to take this exposure route into account. From the 156 existing test guidelines, only those for fish and amphibians partly consider a potential route of uptake via food. From the remaining invertebrate guidelines, those focussing on chronic endpoints may be most suitable to cover this exposure path. We suggest assessing the food-related effects of systemic pesticides in a dose-dependent manner using standardized guidelines or methods developed from peer-reviewed literature. For transgenic plants, spiking uncontaminated leaf material with increasing concentrations of the test substances would allow to test for dose responses. After adaption to oral uptake, standard test guidelines currently available for the ERA appear, in principle, suitable for testing effects of systemic pesticides and transgenic plants.

Engineered gene drives are an emerging technology for the large-scale genetic modification of natural populations of species. They are controversial due to high levels of uncertainty about their risks and benefits. We analyze gene drives in their social, natural, and technological contexts.
We discuss their depth of intervention and compare gene drives to "conventional" genetic modification techniques and to other novel high-impact technologies. While gene drives might overpromise and under-deliver solutions for problems of sustainable development, they also represent
a paradigm shift in human technological interference with nature, thus requiring broad discussion in society.