Fate of 14C‐allylalcohol herbicide in soils and crop residues

Abstract

Residue disappearance and leaching of ¹⁴C‐allyl‐alcohol from different soils were studied in laboratory experiments. Additionally, the uptake of residues by lettuce and carrots was investigated in the greenhouse. In laboratory experiments, residue disappearance and leaching from soils was correlated negatively to the organic matter content. In greenhouse experiments with a sandy loam soil at an application rate normally used in practice, an average of 12.5 % of the applied radioactivity was recovered after an eight day interval between application and sowing. Furthermore, an average of 8 % (sum in soil and plants) of the applied radioactivity was recovered after lettuce or carrot growing. Uptake of residues was higher by carrots than by lettuce, and higher by lettuce roots than by lettuce tops. No bioaccumulation was observed. The residues in soils and plants were, to a high percentage, unextractable and, to a smaller extent, fully water‐soluble products. Unchanged allylalcohol could not be detected by the analytical methods used.     

Application of a Swab Sampling Method for the Detection of Norovirus and Rotavirus on Artificially Contaminated Food and Environmental Surfaces

Noroviruses and rotaviruses are the leading causes of non-bacterial gastroenteritis in humans worldwide. Virus-contaminated food and surfaces represent an important risk to public health. However, established detection methods for the viruses in food products are laborious and time-consuming. Here, we describe a detailed swabbing protocol combined with real-time RT-PCR for norovirus and rotavirus detection on artificially contaminated food and environmental surfaces. Recovery rates between 2 and 78% for norovirus and between 8 and 42% for rotavirus were determined for contaminated food surfaces of apple, pepper, cooked ham and salami. From contaminated environmental surfaces (stainless steel, ceramic plate, polyethylene, wood), recovery rates between 26 and 52% (norovirus) and between 10 and 58% (rotavirus) were determined. The results demonstrate the suitability of the swab sample method for virus detection on food and environmental surfaces. Compared to other methods, it is easy to perform and significantly time-saving, predestining it for routine testing.     

Caveats to quantifying ecosystem services: fruit abortion blurs benefits from crop pollination.

The recent trend to place monetary values on ecosystem services has led to studies on the economic importance of pollinators for agricultural crops. Several recent studies indicate regional, long-term pollinator declines, and economic consequences have been derived from declining pollination efficiencies. However, use of pollinator services as economic incentives for conservation must consider environmental factors such as drought, pests, and diseases, which can also limit yields. Moreover, "flower excess" is a well-known reproductive strategy of plants as insurance against unpredictable, external factors that limit reproduction. With three case studies on the importance of pollination levels for amounts of harvested fruits of three tropical crops (passion fruit in Brazil, coffee in Ecuador, and cacao in Indonesia) we illustrate how reproductive strategies and environmental stress can obscure initial benefits from improved pollination. By interpreting these results with findings from evolutionary sciences, agronomy, and studies on wild-plant populations, we argue that studies on economic benefits from pollinators should include the total of ecosystem processes that (1) lead to successful pollination and (2) mobilize nutrients and improve plant quality to the extent that crop yields indeed benefit from enhanced pollinator services. Conservation incentives that use quantifications of nature's services to human welfare will benefit from approaches at the ecosystem level that take into account the broad spectrum of biological processes that limit or deliver the service.     

Pedestrians' estimates of their own visibility: a simple and effective computer-based technique

INTRODUCTION: Research has shown that both pedestrians and drivers drastically overestimate pedestrians' nighttime visibility (NHSTSA, 2008a, 2008b; Owens & Sivak, 1996) and fail to appreciate the safety benefits of proven conspicuity aids. One solution is educational intervention (Tyrrell, Patton, & Brooks, 2004); however, the on-road assessment of its effectiveness is expensive and time consuming. METHOD: Experiment One introduces a computer-based alternative to the field-based approach, successfully replicating the previous study's trends among 94 students who either receive or do not receive an educational lecture. Experiment Two utilizes the simulation's portability to determine if professional roadway workers have a more accurate understanding of pedestrian conspicuity than students. Results: Results among 88 workers show they do not significantly appreciate the advantages of effective retroflective material configurations or vehicle headlamp settings, for example, any better than non-lectured students in Experiment One. Impact: The study's results demonstrate the need for education among all pedestrians and the benefits of efficient testing methods.     

Investigations on the binding mechanism of the herbicide simazine to dissolved organic matter in leachates of compost

14C-labelled simazine was composted together with biowaste on a pilot (m3) scale. The herbicide was quickly bound to the compost matrix. By aqueous extraction of 29 and 200 days old compost (equivalent to thermophilic and mesophilic phase of composting) only 4.2% and 3.1% respectively of the radioactivity in the compost samples could be extracted with water. Analysis of the extracts using high-performance size exclusion chromatography (HPSEC) revealed that the dissolved organic matter (DOM) had molecular weights ranging between 2 and 28 kDa. The amount of DOM-associated radioactivity increased from 53% (day 29) to 65% (day 200) of total extractable radioactivity. The type of binding of the 14C-labelled residues and the DOM was elucidated by silylation of humic matter and subsequent HPSEC. The data demonstrated that besides polar metabolites also intact simazine was bound to the DOM. A distinct shift from rather weak interactions to strong covalent linkages of simazine and its metabolites with increasing age of the compost was observed. The results showed that only low amounts of free simazine and its degradates can be extracted with water. We concluded that the shift towards stable covalent linkages is equivalent to a detoxification of the contaminant in aged compost. Consequently, the use of the analysed compost in its mature stage should not pose an environmental risk to the groundwater or the subsoil.