The aim of this study--to identify the main trends in the use of pesticides at the present stage. Since 2004, in the Republic of Tatarstan, there is observed an increase of the discharge of pesticides, the list of drugs and cultivated area. The introduction of minimum tillage on technology was shown to have led to an increase in the share of herbicide to 86.2% and significantly changed their range. Glyphosate became the main active ingredient.
Climate change is not only likely to improve conditions for crop production in Sweden, but also to increase weed pressure and the need for herbicides. This study aimed at assessing and contrasting the direct and indirect effects of climate change on herbicide leaching to groundwater in a major crop production region in south-west Sweden with the help of the regional pesticide fate and transport model MACRO-SE. We simulated 37 out of the 41 herbicides that are currently approved for use in Sweden on eight major crop types for the 24 most common soil types in the region. The results were aggregated accounting for the fractional coverage of the crop and the area sprayed with a particular herbicide. For simulations of the future, we used projections of five different climate models as model driving data and assessed three different future scenarios: (A) only changes in climate, (B) changes in climate and land-use (altered crop distribution), and (C) changes in climate, land-use, and an increase in herbicide use. The model successfully distinguished between leachable and non-leachable compounds (88% correctly classified) in a qualitative comparison against regional-scale monitoring data. Leaching was dominated by only a few herbicides and crops under current climate and agronomic conditions. The model simulations suggest that the direct effects of an increase in temperature, which enhances degradation, and precipitation which promotes leaching, cancel each other at a regional scale, resulting in a slight decrease in leachate concentrations in a future climate. However, the area at risk of groundwater contamination doubled when indirect effects of changes in land-use and herbicide use, were considered. We therefore concluded that it is important to consider the indirect effects of climate change alongside the direct effects and that effective mitigation strategies and strict regulation are required to secure future (drinking) water resources.
Although direct contact during mixing/loading, application or repair and clean-up is the major pathway by which individuals living on farms are exposed to herbicides, indirect sources such as contact with contaminated surfaces may also contribute. As part of a biomonitoring study to measure the nature and extent of exposure of farm families to herbicides, we attempted to identify potential indirect sources of exposure in a subset of 32 Ontario farms. Herbicide residues in drinking water samples as well as surface swipes of common surfaces within the home were measured and compared with urinary concentrations of the applicator, spouse and child. Residues of 2,4-dichlorophenoxyacetic acid (2,4-D) were measured on all surfaces that were tested, with the highest levels found on the washing machine knob and wash-up faucet within the home. Drinking water was not a significant source of exposure to 2,4-D for farm families. Urine samples of family members were weakly correlated with residues of 2,4-D measured on the exterior door knob. The applicators in our study, the most highly exposed subpopulation in our study group, had exposures that were less than one-third of the exposure on a daily, lifetime basis deemed to be safe by regulatory agencies in Canada and the United States. As 2,4-D residues were detected on surfaces in farm homes where 2,4-D was not reportedly used at that time, this suggests that 2,4-D applied during a previous season (or on a neighbouring farm) may be tracked into the home and persist on hard surfaces and be a chronic, albeit low level, source of exposure for family members. Pesticide applicators and their families should be counselled on hygienic practices (e.g. removing footware and washing soiled hands prior to entering the home) to reduce indirect sources of exposure. Journal of Exposure Science and Environmental Epidemiology (2006) 16, 98-104. doi:10.1038/sj.jea.7500441; published online 13 July 2005.
An LC-MS/MS method for analysing glyphosate and aminomethylphosphonic acid (AMPA) in cereals was developed. The method is based on extraction with water and detection of the ions from the fragmentation m/z 170-->88 (glyphosate) and m/z 112-->30 (AMPA), using electrospray interface in the positive mode. Investigation from the harvests of 1998 and 1999 showed residues of glyphosate and/or its degradation product AMPA in more than half of the cereal samples produced in Denmark. The average concentration of glyphosate in 46 samples from the 1999 harvest was 0.11 mg/kg compared with 0.08 mg/kg for the 1998 harvest (n = 49). Thus, the figures were well below the maximum residue limit (MRL) and no violations were observed. The plant growth regulators chlormequat and/or mepiquat were investigated in cereals from the Danish harvest of 1999 where 83% of the samples contained chlormequat (n = 46) compared with 87% of the samples from the 1997 harvest (n = 52). The average concentration of chlormequat in 1999 was 0.32 mg/kg compared with 0.23 mg/kg in 1997. At 2.9 mg/kg, one sample of wheat bran was exceeding the MRL of 2 mg/kg for wheat. The intakes of the pesticides through the diet of cereals were estimated to comprise 0.04% of the acceptable daily intake (ADI) for glyphosate and 1% of the ADI for chlormequat for an adult Dane.
In the Yukon Territory, transmission rights-of-way (ROWs) are managed using brushing and mowing techniques alone. When cut, target species such as Michx. and spp. grow rapidly shortening maintenance cycles. Long-term vegetation control may be improved by integrating herbicide application. However, prior to implementation, the dissipation and toxicity of herbicides in northern latitudes needed to be assessed. The dissipation of Garlon XRT (triclopyr) and Arsenal Powerline (imazapyr) in soils was assessed at five ROW locations representative of the main ecoregion types where ROWs occur within the Yukon Territory. Soils from four sites were collected at 1, 30, and 365 d after treatment to determine persistence of herbicides for each of three application methods (backpack spraying, cut stump, and point injection). Increased sampling intervals were added to better determine the dissipation rate of each herbicide in Yukon Territory soils. Soil dissipation data were linked to a series of standardized toxicity tests, including three soil invertebrates (, , and ). Additionally, the dissipation of both herbicides from the target species L. was assessed at one site. Herbicide residues persisted in soils for longer than 365 d after treatment and longer than 30 d after treatment in . However, concentrations were below the concentration that would affect 25% of the invertebrate species tested. Weight of evidence and toxic exposure ratios were used to characterize the risks associated with herbicide application in northern latitudes and provided both qualitative and quantitative means to communicate the results to the public.