We investigated the biological response of soluble organic fraction (SOF) and water-soluble fraction (WSF) extracted from particulate matter (PM) emitted by an automotive diesel engine operating in a representative urban driving condition. The engine was fueled with ultra-low sulfur diesel (ULSD), and its binary blends by volume with 13% of butanol (Bu13), and with hydrotreated vegetable oil (HVO) at 13% (HVO13) and 20% (HVO20). Cytotoxicity, genotoxicity, oxidative DNA damage and ecotoxicity tests were carried out, and 16 polycyclic aromatic hydrocarbons (PAH) expressed as tbenzo(a)pyrene total toxicity equivalent (BaP-TEQ) were also analyzed. The Hepatocarcinoma epithelial cell line (HepG2) was exposed to SOF for 24 h and analyzed using comet assay, with the inclusion of formamidopyrimidine DNA glycosylase (FPG) and endonuclease III (Endo III) to recognize oxidized DNA bases. The WSF was evaluated through acute ecotoxicity tests with the aquatic microcrustacean Daphnia pulex (D. Pulex). Results showed that there was no cytotoxic activity for all tested SOF concentrations. Genotoxic responses by all the SOF samples were at same level, except for the HVO13 which was weaker in the absence of the enzymes. The addition of the FPG and Endo III enzymes resulted in a significant increase in the comet tail, indicating that the DNA damage from SOF for all tested fuel blends involves oxidative damage including a higher level of oxidized purines for ULSD and Bu13 in comparison with HVO blends, but the oxidized pyrimidines for HVO blends were slightly higher compared to Bu13. The WSF did not show acute ecotoxicity for any of the fuels. Unlike other samples, Bu13-derived particles significantly increase the BaP-TEQ. The contribution to the genotoxic activity and oxidative DNA from SOF was not correlated to BaP-TEQ, which means that the biological activity of PM might be affected also by other toxic compounds present in particulate phase.

Current pesticide registration guidelines call for short-term testing of plants; long-term effects on vegetative parts and reproduction remain untested. The aims of our study were to determine level of recovery and recovery times for plants exposed to the sulfonylurea herbicide chlorimuron ethyl using data collected from single species, dose–response greenhouse experiments. The nine terrestrial and eight wetland species tested showed variable levels of recovery and recovery timeframes. Many species (six terrestrial and five wetland) were vegetatively stunted at sublethal doses and were reproductively impaired. Full recovery did not occur at all doses and maximum recovery times varied from 3 to 15 weeks in this controlled environment. In a complex community, affected species may be displaced by tolerant species, through interspecific competition, before they fully recover. It is plausible that individual populations could be diminished or eliminated through reduced seedbank inputs (annuals and perennials) and asexual reproduction (perennials).

It can be suggested that the combined stress of pesticide pollution and suboptimal temperature influences the sensitivity of life stages of aquatic invertebrates differently.The embryo, juvenile, half- and full-life-cycle toxicity tests performed with the snail Physella acuta at different concentrations (0.06–0.5 or 1.0 mg L−1) of the model fungicide pyrimethanil at 15, 20 and 25 °C revealed, that pyrimethanil caused concentration-dependent effects at all test temperatures. Interestingly, the ecotoxicity of pyrimethanil was higher at lower (suboptimal) temperature for embryo hatching and F1 reproduction, but its ecotoxicity for juvenile growth and F0 reproduction increased with increasing temperature.The life-stage specific temperature-dependent ecotoxicity of pyrimethanil and the high fungicide susceptibility of the invasive snail clearly demonstrate the complexity of pesticide–temperature interactions and the challenge to draw conclusions for the risk of pesticides under the impact of global climate change.

Sulfonylurea herbicides are extensively widespread for the protection of a variety of crops and vegetables because of their low application rates, high selectivity and low persistency in the environment; unfortunately, their low persistence does not always correspond to a lower toxicity, since new species potentially more toxic and stable than the precursor herbicides can form, owing to natural degradation processes. Here, the photodegradation of amidosulfuron in aqueous solutions was studied by high-performance liquid chromatography with diode array detection and tandem mass spectrometry to identify the degradation products in order to outline the environmental fate of the molecules generating from the simulation of one of the natural processes that can occur, i.e., photoinduced degradation. The photodegradation process results in a first order kinetic reaction with a t₁/₂value of 276 h (11.5 days) and a kinetic constant of 0.0027 h⁻¹, and three possible degradation products were identified. The results obtained are then compared to those obtained in previous works carried out in comparable experimental conditions about nicosulfuron and tribenuron-methyl, two sulfonylurea herbicides belonging to different classes, and to literature data: hypotheses on the existence of preferential degradation pathways are then drawn, in consequence of the molecular structure of the sulfonylurea pesticide. In particular, the use of organic solvents to obtain complete solubilization of the sample plays a fundamental role and deeply influences the degradation processes that, therefore, not always fully adhere to the actual natural photodegradation pathways. Moreover, considerations about toxicity were driven since the complete mineralisation of the sample is not reached: even when the parent pesticides are totally degraded, they are, however, transformed into other organic compounds showing, if subject to ecotoxicological tests, at least the same toxicity of the precursor herbicides. The evidence here presented suggests that, at least for the class of sulfonylurea pesticides, their professed low persistence actually does not produce any real advantage.

Introduction Chlorimuron-ethyl has been widely used for the soybean production of China, but less information is available on the possible risk of long-term application of this herbicide. Materials and methods In this paper, soil samples were collected from the plots having been received 30 g active component of chlorimuron-ethyl/ha per year for 5 and 10 years in a continuously cropped soybean field of Northeast China, with their microbial community analyzed by plate counting, PCR-DGGE, and cloning library. Chlorimuron-ethyl had a higher accumulation in test soils, and the accumulation decreased the CFU of soil bacteria and increased the CFU of soil fungi significantly. The CFU of soil actinomycetes only had a significant decrease in the plot having been received chlorimuron-ethyl for 10 years. Results and discussion Under the long-term stress of chlorimuron-ethyl, the diversity and evenness of soil microbial community decreased, and more importantly, some bacterial and fungal species that possibly benefited soybean's growth, e.g., Acidobacteria, γ-proteobacteria, Cortinarius violaceu, Acarospora smaragdula, and Xerocomus chrysenteron decreased or demised, while some species that could induce the obstacle of soybean's continuous cropping, e.g., Fusarium oxysporum, Rhizoctonia solani, and Phytophthora sojae, increased or appeared. Some actinomycetes were inhibited having negative effects on the antagonism between soil microbes. It is considered that due to the longer half-life of chlorimuron-ethyl in soil and the resistance and resilience of soil microbes to short-term environmental stress, long-term in situ investigation rather than laboratory microcosm test or short-term field experiment would be more appropriate to the accurate assessment of the ecological risk of long-term chlorimuron-ethyl application. Further studies should be made on the application mode and duration of chlorimuron-ethyl to reduce the possible ecological risk of applying this herbicide on continuously cropped soybean field.

A method by GC/MS has been established for the determination of Pyrimidifen in agricaltural products. The Pyrimidifen in agricultural products is extracted with acetone, concentrated, and extracted with n-hexane. The solution is cleaned up with a Florisil column and subjected to a determination by GC/MS using p-terphenyl-d14 as the internal standard. This method is featured by the recovery over 80 % with its C .V. below 8 % and the detection limit 1 micro g/kg. This method, excellent in sensitivity and selectivity, is useful as a rutine analytical method for agricultural products.