强化微电解法预处理难降解农药废水

为了更好地发挥微电解法预处理难降解农药废水的效能,对其进行强化研究。针对某难降解农药废水,考察了Cu/Fe双金属体系、Ni/Fe双金属体系、添加MnO2催化剂及超声波、电解与铁炭分别结合这5种强化途径去除COD的效果。结果表明,这5种强化途径对污染物的去除率分别为72.3%、68.0%、67.8%、70.0%和76.8%,相比于单独微电解,COD去除率均有较大提高。结合经济成本的考虑,镀Cu双金属微电解体系能够实现经济高效地预处理农药废水。     

Consumer health risk to pesticide residues in Salvia officinalis L. and its infusions

Salvia officinalis L. is a popular herb widely used in culinary, cosmetic, and medicinal preparations, and also as an ornamental plant. Sage crops are threatened by many diseases, such as gray mold, powdery mildew, and leaf spot, by weeds, and by pests, such as aphids. Use of crop protection products may lead to presence of pesticide residues in this herb. The aim of this work was to study presence of pesticide residues in the herb, S. officinalis L., available on the retail market in Poland, to verify their compliance with the maximum residue levels (MRLs) and to assess the chronic and acute risks associated with consumption of this herb and infusions prepared from contaminated sage plants. Ninety active substances of pesticides were analyzed, including all active substances registered in Poland for protection of the sage. Five active substances were found, one fungicide – boscalid and four insecticides: chlorpyrifos, pp′-DDT, dimethoate (residue levels above MRL) and indoxacarb. The chronic and acute exposure to pesticide residues consumed with sage did not exceed 0.02% of the acceptable daily intake (ADI) and 0.1% of the acute reference dose (ARfD), respectively.     

An alkaline phosphatase from Bacillus amyloliquefaciens YP6 of new application in biodegradation of five broad-spectrum organophosphorus pesticides

In recent decades, biodegradation has been considered a promising and eco-friendly way to eliminate organophosphorus pesticides (OPs) from the environment. To enrich current biodegrading-enzyme resources, an alkaline phosphatase (AP3) from Bacillus amyloliquefaciens YP6 was characterized and utilized to test the potential for new applications in the biodegradation of five broad-spectrum OPs. Characterization of AP3 demonstrated that activity was optimal at 40?°C and pH 10.3. The activity of AP3 was enhanced by Mg²⁺, Ca²⁺, and Cu²⁺, and strongly inhibited by Mn²⁺, EDTA, and L-Cys. Compared to disodium phenyl phosphate, p-nitrophenyl phosphate (pNPP) was more suitable to AP3, and the V_m, K_m, k_cat, k_cat/K_m values of AP3 for pNPP were 4,033?U mg^?1, 12.2?mmol L^?1, 3.3?×?10⁶ s^?1, and 2.7?×?10⁸ s^?1mol^?1L, respectively. Degradation of the five OPs, which included chlorpyrifos, dichlorvos, dipterex, phoxim, and triazophos, was 18.7%, 53.0%, 5.5%, 68.3%, and 96.3%, respectively, after treatment with AP3 for 1?h. After treatment of the OP for 8?h, AP3 activities remained more than 80%, with the exception of phoxim. It can be postulated that AP3 may have a broad OP-degradation ability and could possibly provide excellent potential for biodegradation and bioremediation in polluted ecosystems.     

Effect of individual parameter changes on the outcome of the estimated short-term dietary exposure to pesticides

ABSTRACT

In 2015 a scientific workshop was held in Geneva, where updating the International Estimate of Short-Term Intake (IESTI) equations was suggested. This paper studies the effects of the proposed changes in residue inputs, large portions, variability factors and unit weights on the overall short-term dietary exposure estimate. Depending on the IESTI case equation, a median increase in estimated overall exposure by a factor of 1.0-6.8 was observed when the current IESTI equations are replaced by the proposed IESTI equations. The highest increase in the estimated exposure arises from the replacement of the median residue (STMR) by the maximum residue limit (MRL) for bulked and blended commodities (case 3 equations). The change in large portion parameter does not have a significant impact on the estimated exposure. The use of large portions derived from the general population covering all age groups and bodyweights should be avoided when large portions are not expressed on an individual bodyweight basis. Replacement of the highest residue (HR) by the MRL and removal of the unit weight each increase the estimated exposure for small-, medium- and large-sized commodities (case 1, case 2a or case 2b equations). However, within the EU framework lowering of the variability factor from 7 or 5 to 3 counterbalances the effect of changes in other parameters, resulting in an estimated overall exposure change for the EU situation of a factor of 0.87-1.7 and 0.6-1.4 for IESTI case 2a and case 2b equations, respectively.     

气相色谱-脉冲火焰光度检测器测定痕量有机磷农药

在水样和土壤样中分别加入二氯甲烷和丙酮，用超声波提取水样中敌敌畏、乐果、甲基对硫磷、马拉硫磷、对硫磷等5种有机磷农药和土壤样中甲拌磷、二嗪磷、异稻瘟净、杀螟农、溴硫磷、水胺硫磷、稻丰散、杀扑磷等8种有机磷农药，大大地简化了测定的预处理过程。应用气相色谱法HP—5石英毛细管柱分离，脉冲式火焰光度检测器检测，取得了较好的测定结果。水样中农药的检测限≤0．O02mg／L，土壤样中农药的检测限≤0．O02mg／kg，相对标准偏差水样＜7％，土壤样＜10％，加标回收率水样在84％—96％之间，土壤样在80％—108％之间，均满足测定要求。     

Distribution of pesticide residues in soil and uncertainty of sampling

Pesticide residues were determined in about 120 soil cores taken randomly from the top 15 cm layer of two sunflower fields about 30 days after preemergence herbicide treatments. Samples were extracted with acetone-ethyl acetate mixture and the residues were determined with GC-TSD. Residues of dimethenamid, pendimethalin, and prometryn ranged from 0.005 to 2.97 mg/kg. Their relative standard deviations (CV) were between 0.66 and 1.13. The relative frequency distributions of residues in soil cores were very similar to those observed in root and tuber vegetables grown in pesticide treated soils. Based on all available information, a typical CV of 1.00 was estimated for pesticide residues in primary soil samples (soil cores). The corresponding expectable relative uncertainty of sampling is 20% when composite samples of size 25 are taken. To obtain a reliable estimate of the average residues in the top 15 cm layer of soil of a field up to 8 independent replicate random samples should be taken. To obtain better estimate of the actual residue level of the sampled filed would be marginal if larger number of samples were taken.     

超声辅助乳化液相微萃取分析绿茶饮料和番茄汁中有机磷农药残留

农药施用于田间,必然会残留于环境中。农药残留的分析方法多种多样。为探究灵敏度高、重现性好的样品前处理方法,建立了超声辅助乳化液相微萃取,结合气相色谱和火焰光度检测器测定绿茶饮料和番茄汁中5种有机磷农药的方法,对萃取条件进行了优化,如萃取溶剂种类和体积、超声频率和时间、盐效应。在优化后的萃取条件下,5种有机磷农药实现良好分离,空白添加实验结果表明在0.1~10μg·L-1之间,线性相关系数在0.9985~0.9994之间,检测限在0.005~0.020μg·L-1之间,相对标准偏差(n=5)在4.3%~9.4%之间。在绿茶饮料和番茄汁实际样本检测中,目标分析物含量均低于检出限。样本添加回收试验的回收率均大于88.5%,相对标准偏差(n=3)在2.2%~9.8%之间,结果表明该方法用于液体样本中农药残留检测真实可靠。     

Concentration and dissipation of chlorantraniliprole and thiamethoxam residues in maize straw,maize, and soil

To study the dissipation rates and final residual levels of chlorantraniliprole and thiamethoxam in maize straw, maize, and soil, two independent field trials were conducted during the 2014 cropping season in Beijing and Anhui Provinces of China. A 40% wettable powder (20% chlorantraniliprole?+?20% thiamethoxam) was sprayed onto maize straw and soil at an application rate of 118 g of active ingredient per hectare (g a.i.ha^?1). The residual concentrations were determined by ultra-high-performance liquid chromatography–tandem mass spectrometry. The chlorantraniliprole half-lives in maize straw and soil were 9.0–10.8 and 9.5–21.7 days, respectively. The thiamethoxam half-lives in maize straw and soil were 8.4–9.8 and 4.3–11.7 days, respectively. The final residues of chlorantraniliprole and thiamethoxam in maize straw, maize, and soil were measured after the pesticides had been sprayed two and three times with an interval of 7 days using 1 and 1.5 times the recommended rate (72 g a.i. ha^?1 and 108 g a.i. ha^?1, respectively). Representative maize straw, maize, and soil samples were collected after the last treatment at pre-harvest intervals of 7, 14, and 28 days. The chlorantraniliprole residue was below 0.01 mg kg^?1 in maize, between 0.01 and 0.31 mg kg^?1 in maize straw, and between 0.03 and 1.91 mg kg^?1 in soil. The thiamethoxam residue concentrations in maize, maize straw, and soil were <0.01, <0.01, and 0.01–0.03 mg kg^?1, respectively. The final pesticide residues on maize were lower than the maximum residue limit (MRL) of 0.02 mg kg^?1 after a 14-day pre-harvest interval. Therefore, a dosage of 72 g a.i. ha^?1 was recommended, as it can be considered safe to human beings and animals.     

Effect of the pesticide lindane on the biomass of the microalgae Nannochloris oculata

This study assesses the growth of the microalgae Nannochloris oculata in the presence of lindane and the ability of N. oculata to remove lindane from media. Algal biomass increased with 0.1 and 0.5 mg L^?1 of lindane, and lindane concentrations in the media decreased. N. oculata removed 73% and 68.2% of lindane in the 0.1 and 0.5 mg L^?1 media concentrations, respectively. Algal biomass decreased to the level of the control at lindane concentrations greater than 2.5 mg L^?1, probably due to toxicity. N. oculata removed lindane from the media at concentrations lower than 1.0 mg L^?1. Thus, N. oculata may be useful for lindane bioremediation in contaminated aquatic systems.     

The importance of skillful community leaders: understanding municipal pesticide policy change in Calgary and Halifax

This paper focuses on policy change under scientific uncertainty. This is done by exploring two case studies of Canadian pesticide policy evolution applied to Sabatier's ‘Advocacy Coalition Framework’. ‘Stakeholder’ and ‘narrative policy’ analyses are emphasised to understand pesticide policy changes in Calgary (public education without a restrictive by-law) and Halifax (restrictive by-law). The parallel case studies consist of qualitative interviews with members of pesticide policy advisory committees in each city and a content analysis of local newspaper articles. Key resources mobilised by coalitions to achieve their policy goals include skillful leadership, and the use by those leaders of the media to disseminate coalition narratives. Further, the context of policy change contributed to the scenarios whereby pro-by-law grassroots activists were particularly successful in Halifax and anti-by-law city employees were most influential in Calgary.