在线固相萃取-HPLC法测定公共绿地土壤中新烟碱类农药残留

土壤样品经二氯甲烷-乙腈混合溶液超声提取后,用PEP固相萃取柱在线净化,再用HPLC法测定样品中吡虫啉、啶虫脒、噻虫嗪、噻虫啉、烯啶虫胺等5种新烟碱类农药残留。通过优化试验条件,使该方法在0.01 mg/L~2.00 mg/L范围内线性良好,当取样量为3.00 g时,方法检出限为0.002 mg/kg~0.003 mg/kg。8种土壤样品3个质量比水平的加标回收率为72.5%~119%,RSD均低于9.6%。     

Recovery of molybdenum, phosphorus and arsenic fromleaching solution of molybdenum residues by solvent extraction with primary amine and tributylphosphate

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Pesticides in the surface waters of the Camanducaia River watershed,Brazil

Abstract

Camanducaia River is part of the Piracicaba watershed responsible for pumping water into the Cantareira System, which is one of the main water sources for the metropolis of São Paulo and Campinas, Brazil. Intensive use of pesticides and hilly topography represents a situation of high risk for river water contamination. Therefore, water samples from 12 locations were collected along the Camanducaia River and its tributaries, over a period of 4?mo during the rainy season, and analyzed by GC-MS/MS or UPLC- MS/MS for the presence of 46 pesticides. Seven pesticides (fipronil, methyl parathion, metolachlor, atrazine, carbofuran, diuron, and simazine) were positively detected. Only atrazine (the most frequently detected) and diuron were present at concentrations above the limit of quantification of the analytical method (0.32 and 0.57?μg L^?1 for atrazine and diuron, respectively). Pesticides detection frequency was higher than expected for a river system where only 11.8% of the land area is under agriculture. The vulnerability of the Camanducaia basin to pesticide contamination is attributed to the high annual precipitation (> 1.5?m y^?1 in the headwaters), associated with topographical features (steep terrain) and soil types that favor surface runoff, which has been exacerbated by poor soil management practices.     

气相色谱法测定糙米中水胺硫磷和甲基异柳磷的残留量

本文用带氮磷检测器的气相色谱仪,测定糙米中水胺硫磷和甲基异柳磷残留量,结果表明:水胺硫磷和甲基异柳磷最小检出量分别为1.3×10~(-11)g和2.8×10~(-12)g,最低检出浓度分别为0.7ppb和0.1ppb,回收率添加浓度为0.05—5mg/kg时,回收率范围分别为89.9—97.8％和100.7—104.9％,变异系数绝对值分别为3.42—5.58％和1.33—2.36％。     

Yield and quality of charcoals from olive mill residues and its stone and pulp fractions: An enhanced comparative study

Pyrolysis is a promising way to upgrade large amounts of residues from olive oil processing into charcoal. Pyrolysis of the stone and pulp fractions needed to be investigated before conclusions could be drawn. We subjected the olive stone fraction, the pulp fraction, and a mixture of the two to dynamic pyrolysis and isothermal pyrolysis at 360°C. We characterized the charcoals resulting from isothermal pyrolysis at 360°C for different durations in terms of the fixed-carbon content (FCC), carbon content (CC), and high heating value (HHV). We found that charcoal yield from the pulp was higher than that from the stones, which were 38.1% and 32.9%, respectively, after pyrolysis for 360 min. This seemingly unexpected result was due to the high contents of ash (6.22%) and extractives (13%) in the pulp, which remained completely and partially undecomposed, respectively, in the charcoals and are accounted for when calculating yields. However, charcoals obtained from the stones were of higher quality than charcoals from the pulp, with lower ash content and higher FCC, CC, and HHV. In particular, the FCC, CC, and HHV after pyrolysis for 360 min were 73.2%, 74.4%, and 30.2 MJ/kg for the stones and only 61.8%, 63.2%, and 25.9 MJ/kg for the pulp, respectively. Depending on the required quality of the final charcoal, our results help decide whether to pyrolyse the entire olive residues or only one of the two fractions, more likely the stones.     

Quality of Meliponinae honey: Pesticides residues,pollen identity,and microbiological profiles

This study aims at evaluating the quality of honey of Melipona quadrifasciata quadrifasciata Tetragonisca angustula and Scaptotrigona depilis. Pollen analysis was performed to identify the floral resources used for the production of honey, and 19 pollen types were identified. Microbiological analyses identified the presence of coliforms, molds, and yeasts, but Clostridium botulinum was not found. Using the modified “Quick, Easy, Cheap, Effective, Rugged, and Safe” method followed by ultra‐high performance liquid chromatography‐tandem mass spectrometry determination, eight pesticides were detected in the honey of T. angustula and only two in the honey from S. depilis. The honey of M. q. quadrifasciata did not present pesticide residues. The data pointed out the relevance of good practices to avoid the contamination of honey with sources of microbiological contaminants, which may impair the product's safety for human consumption.     

Screening of antibiotic residues in fresh milk of Kathmandu Valley,Nepal

The prevalence of two groups of antibiotics; namely penicillin and sulfonamides was studied in fresh milk available in Kathmandu Valley of Nepal. The milk samples (n = 140) were collected from three different sources; individual farmers, cottage dairies and organized dairies of Kathmandu valley. Qualitative and semi-quantitative analysis with rapid screening kits revealed that 23% samples were positive for antibiotic residues in the fresh milk for penicillin and sulfonamide groups (1–256 µg/kg). High performance liquid chromatography (HPLC) analyses detected 81% samples positive for amoxicillin (68–802 µg/kg), 41% for sulfadimethoxine (31–69 µg/kg), 27% for penicillin G (13–353 µg/kg), and 12% for ampicillin (0.5–92 µg/kg). Due to the precision and accuracy of liquid chromatography method, it detected more positive samples and consequently presented higher prevalence than the rapid screening kits. The antibiotic residues were found above the maximum residue limits that presented serious threat to consumer health and raised a serious concern regarding the implementation and monitoring of international regulations in developing countries.     

Monitoring of Organochlorine Pesticide Residues in Summer and Winter Vegetables from Agra, India – A case study

Analysis of summer and winter vegetable samples during 2002–2003 for pesticidal contamination was carried out on Gas Chromatograph-Electron Capture Detector with capillary columns. The contamination levels of winter vegetables (average concentration of 4.57, 6.80 and 5.47 ppb respectively for Lindane, Endosulphan and DDT) were found to be slightly higher than the summer vegetables (average concentration of 4.47, 3.14 and 2.82 ppb respectively for Lindane, Endosulphan and DDT). The concentration of these organochlorine pesticides in summer and winter vegetables were well below the established tolerances but continuous consumption of such vegetables even with moderate contamination level can accumulate in the receptor's body and may lead to chronic effects that could be fatal.     

基于调查的中国秸秆露天焚烧污染物排放清单

基于2010年初农村能源消费情况的问卷调查,获得全国分省秸秆露天焚烧比例,在此基础上确定秸秆露天焚烧的活动水平,采用排放因子法建立中国秸秆露天焚烧的污染物排放清单. 结果表明,中国农村秸秆露天焚烧平均比例为20.8%. 2009年全国28个省区(不包括西藏自治区、天津市、上海市、港澳台地区,下同)秸秆露天焚烧的PM_2.5、BC、OC、SO₂、NO_x、CO、NMVOC、NH₃、CH₄和CO₂排放量分别138.1×104、6.4×104、41.1×104、8.7×104、41.8×104、594.6×104、94.4×104、8.0×104、44.2×104和14 355.4×104 t. 稻谷、玉米和小麦是露天焚烧的三大作物秸秆,其对污染物排放的贡献合计约为87%. 秸秆露天焚烧排放量最高的前3位分别为湖南省、河南省和安徽省, 秸秆露天焚烧比例分别43.1%、20.8%和39.7%. 污染排放的高值区主要集中在华北和华中地区. 95%置信区间下的不确定性分析结果显示,PM_2.5、BC、OC、SO₂、NO_x、CO和NMVOC排放的不确定性范围分别为-60%~83%、-78%~147%、-73%~135%、-48%~75%、-49%~78%、-91%~155%和-67%~94%. 2015年初对六省(湖南省、广东省、江苏省、河南省、黑龙江省和辽宁省)农村能源消费调查的结果显示,2014年江苏省、湖南省和广东省的秸秆露天焚烧比例较2009年均有下降,而辽宁省、黑龙江省和河南省则相对上升. 研究显示,秸秆禁烧政策已取得初步成效,建议国家有关部门进一步加大秸秆禁烧政策的推行力度,完善相关政策措施.      

Persistence and Dissipation of Readymix Formulations of Insecticides In/On Okra Fruits

Dissipation behaviour of ready mix polytrin C 44EC (profenophos 40% + cypermethrin 4%) and spark 36EC (triazophos 35%+.deltamethrin 1%) applied at 1 L/ha in okra crop during Kharif in year 2000 was studied at 0, 1, 3, 5 and 7 days after treatment. Dissipation on 7th day was found to be maximum (98.4%) for profenophos followed by triazophos (86.2%), cypermethrin (73.5%) and deltamethrin (55.7%). Half life (t1/2) values for the above insecticides were 1.35, 2.55, 4.11 and 7.60 days, respectively. All the insecticides followed a first order kinetics. Profenophos and triazophos followed a biphasic dissipation pattern with faster dissipation in phase I (0–1 days) and manifesting slower rate of dissipation in phase II (1–7 days).