Persistent Organochlorine Pesticide Residues in Soil and Surface Water of Northern Indo-Gangetic Alluvial Plains

This study reports the concentration levels and distribution pattern of the organochlorine pesticide (OCPs) residues in the soil and surface water samples collected from the northern Indo-Gangetic alluvial plains. A total of 31 soil and 23 surface water samples were collected from the study region in Unnao district covering an area of 2150 km² and analyzed for aldrin, dieldrin, endrin, HCB, HCH isomers, DDT isomers/metabolites, endosulfan isomers (α and β), endosulfan sulfate, heptachlor and its metabolites, α-chlordane, γ-chlordane and methoxychlor. In both the soil and surface water samples β- and δ-isomers of HCH were detected most frequently, whereas, methoxychlor was the least detected pesticide. The results showed contamination of soil and surface water of the region with several persistent organic pesticides. The total OCPs level ranged from 0.36–104.50 ng g^–1 and 2.63–3.72 μg L^–1 in soil and surface water samples, respectively.     

气相色谱-火焰光度法测定土壤中有机磷农药残留

土壤样品用正己烷-丙酮(体积比为1∶1)混合溶液提取,配合硅胶小柱净化,用乙酸乙酯洗脱,再用气相色谱-火焰光度法测定待测液中14种有机磷农药残留,方法在0.100 mg/L~1.00 mg/L范围内线性良好,当取样量为10 g时,方法检出限为1.3μg/kg~2.3μg/kg。用该方法测定有机磷的有证标准溶液,结果均在保证值范围内,RSD为2.2%~6.7%。实际土壤样品的13种有机磷农药加标回收率为59.2%~125%(敌百虫除外),敌百虫回收率为0,说明目标物在测定过程中被降解,该方法不适用于敌百虫的测定。     

Can domestic production of iLUC-free feedstock from arable land supply Sweden’s future demand for biofuels?

The increasing biofuel production from agricultural crops has been suggested to cause indirect land use change (iLUC). This increases interest in biofuel feedstocks that qualify as iLUC-free: (1) residues without a market, (2) crops from previously unused arable land, (3) additional crops and (4) biomass from intensified production. In the present study, biofuel potential from such feedstocks was quantified for Sweden and compared against the predicted biofuel demand from agricultural resources in 2030. The results indicate that straw (category 1) could cover up to 37% of future biofuel demand. Grass leys from intensified production (category 4), set-aside and abandoned land (category 2) and excess grass silage (category 1) could cover up to 79%. Intermediate and ecological focus area crops (category 3) could contribute up to 21%. To realize the biofuel targets, a high implementation rate of additional iLUC-free feedstock is needed. Future studies need to investigate impacts of low-iLUC policies.     

南充农村土壤中有机氯农药残留现状分析

本研究以四川省南充市某农村土壤为研究对象,于2010年和2011年连续两年对土壤中有机氯农药(HCH,DDT)残留情况进行了定点监测。研究结果表明,试区土壤HCHs在2011年基本未检出。两年的DDTs的检出率均为100%。OCPs主要残留物为p,p’-DDE,占残留总量75%以上。不同利用类型土壤中有机氯残留总量排序为:菜地>重点污染场地>基本农田>居民聚集区。所有土壤样品中的HCHs含量均达到国家《土壤环境质量标准》(GB15618-1995)一级标准(<0.05mg/kg),DDTs含量均达到二级标准(<0.50mg/kg)。残留污染较轻。     

三七渣固态发酵生产绿色木霉的工艺条件研究

考察了发酵时间、孢子液接种量、固态发酵培养基装料量、培养温度、光照条件等对三七渣固态发酵生产绿色木霉的影响,并采用正交实验优化了发酵工艺条件。结果表明,发酵过程受工艺条件的影响较大,孢子液接种量、固态发酵培养基装料量、发酵时间3个因素的交互作用极显著(p0.01),这3个因素以及它们之间的交互作用对实验结果的影响程度排序为:交互作用固态发酵培养基装料量孢子液接种量发酵时间;在最佳的发酵工艺条件(即培养温度24℃、无光照、接种量20%(1g三七渣接种2mL绿色木霉孢子液)、固态发酵培养基装料量12.5g、发酵时间8d)下,平均产孢量可达10.10×109 cfu/g。     

全氟辛烷磺酸盐(PFOS)在藻渣/小球藻上的吸附行为及机理

为了开发新型廉价生物吸附剂,以高效吸附去除水体中全氟辛烷磺酸盐(PFOS),对小球藻提取生物柴油后的藻渣吸附酸性水体中的PFOS进行了吸附行为及机理的研究。小球藻提取生物质柴油后,比表面积、孔容、孔径几乎没有变化;等电点由3.3降低至2.7;蛋白质含量由51.45%提高到57.35%。在酸性条件下(pH≤3),小球藻和藻渣对PFOS的吸附率均达到99%以上;随着pH值增加至7,二者的吸附去除率迅速降低,但仍保持在22%~26%。小球藻和藻渣对PFOS的最大吸附容量分别为353.69 mg/g和444.83 mg/g。Freundlich模型能较好地拟合二者对PFOS的吸附数据,表明为多层吸附,即小球藻以静电吸引的形式吸附PFOS阴离子,并疏水分配至所含蛋白质中;而藻渣中含量较高的蛋白质对PFOS的疏水性分配作用是导致藻渣吸附量增高的主要原因。     

Metabolic fate of the 14C-labeled herbicide clodinafop-propargyl in a sediment–water system

The metabolic fate of ¹⁴C-phenyl-labeled herbicide clodinafop-propargyl (¹⁴C-CfP) was studied for 28 days in lab assays using a sediment–water system derived from a German location. Mineralization was 5.21% of applied ¹⁴C after 28 days exhibiting a distinct lag phase until day 14 of incubation. Portions of radioactivity remaining in water phases decreased at moderate rate to 18.48% after 28 days; 62.46% were still detected in water after 14 days. Soxhlet extraction of the sediment using acetonitrile released 35.56% of applied ¹⁴C with day 28, while 33.99% remained as non-extractable residues. A remarkable increase of bound ¹⁴C was observed between 14 and 28 days correlating with the distinct increase of mineralization. No correlation was found throughout incubation with microbial activity of the sediment as determined by dimethyl sulfoxide reduction. Dissolved oxygen and pH value of water phases remained almost constant for 28 days. Analyses of Soxhlet extracts of the sediment and ethyl acetate extracts of water phases by radio-TLC and radio-HPLC revealed that CfP was rapidly cleaved to free acid clodinafop (Cf), which was further (bio-) transformed. DT₅₀ values (based on radio-HPLC) were below 1 day (CfP) and slightly above 28 days (Cf). Further metabolites were not detected. Fractionation of humic and non-humic components of the sediment demonstrated that CfP's non-extractable residues were predominantly associated with fulvic acids up to 14 days of incubation (3.36%), whereas after 28 days, the majority of radioactivity was found in the humin/mineral fraction (13.30% of applied ¹⁴C). Due to high-performance size-exclusion chromatography of the fulvic acids fraction derived from assays incubated for 28 days, this portion of ¹⁴C was firmly, possibly covalently bound to fulvic acids and did not consist of CfP or Cf. Using an isolation strategy comprising preincubation of sediment with CfP and mineralization of ¹⁴C-CfP as criterion, a microorganism was isolated from the sediment examined. It grew on ¹⁴C-CfP as sole carbon source with evolution of ¹⁴CO₂. The bacterium was characterized by growth on commonly used carbon sources and 16S rDNA sequence analysis. Its sequence exhibited high similarity with that of Nocardioides aromaticivorans strain H-1 (98.85%; DSM 15131, JCM 11674).     

Pesticide residues in Italian Ready-Meals and dietary intake estimation

The investigations carried out during 2005 by state-run Italian laboratories within the framework of controls seeking pesticide residues monitoring in foodstuffs involve quantifying the levels of such residues in fruit and vegetable produce and their processed products: oil, wine and fruit juices. The Italian Ready-Meal Residue Project, promoted by the pesticides working group of Italian Environmental Agencies, seeks to asses the quantity of pesticides in pre-prepared (ready-to-eat) lunches (comprising a first course, side dish, fruit, bread and wine), and to quantify the amounts consumed and compare with the acceptable daily intake ADIs.The data provided by 16 laboratories which analyzed 50 complete meals in 2005 (samples taken on 8 February, 26 May, 24 October, 21 December 2005) showed residues in 39 lunches, with an average number of 2.4 pesticides in each meal and a maximum of 10 pesticides. The most frequently found substances were: pirimiphos-methyl (20 times), procymidone (17), pyrimethanil (7), iprodione (7), cyprodinil (7), fenitrothion (6), diphenylamine (6), chlorpyrifos (6), metalaxyl (5) and chlorpyrifos-methyl (5).The distribution of residues among each dish of the meal was also examined, and the results showed that: 77.3% of the residues were present in the fruit, 14.9% in the wine, 3.0% in the main course, 2.8% in the bread and 2.1% in the side dish. Assuming that two meals are consumed per day, the daily intake of pesticide residues was calculated on a daily basis, in relation to normal body weight (60 kg for an adult, 40 kg for a teenager, 20 kg for a child) and compared with the ADI values established by the European Union. In the case of adults, the average daily intake of pesticides in relation to ADI was 2.6% with a maximum of 73.3%; for teenagers it was 4.9% with a maximum of 109% and for children it was 9.8% with a peak of 219%.     

Fate of 14C-ethyl prothiofos insecticide in canola seeds and oils

Canola plants were treated with ¹⁴C- prohiofos under conditions simulating local agricultural practices. ¹⁴C-residues in seeds were determined at different time intervals. At harvest time about 32 % of ¹⁴C-activity was associated with oil. The methanol soluble ¹⁴C-residues accounted for 12 % of the total seed residues after further seeds extraction, while the cake contained about 49 % of the total residues. About 69 % of the ¹⁴C-activity in the crude oil could be eliminated by simulated commercial processes locally used for oil refining. Chromatographic analysis of crude and refined oil revealed the presence of the parent compound together with three metabolites which were identified as prothiofos oxon, O-ethyl phosphorothioate and O-ethyl S-propyl phosphorothioate, besides one unknown compound. While methanol extract revealed the presence of despropylthio prothiofos and O-ethyl phosphoric acid as free metabolites acid hydrolysis of the conjugated metabolites in the methanol extract yielded 2, 4-dichlorophenole which was detected by color. When rats were fed the extracted cake for 72 hours, the bound residues were found to be bioavailable. The main excretion route was via the expired air (42 %), while the ¹⁴C-residues excreted in urine and feces were 30 % and 11 %, respectively. The radioactivity detected among various organs accounted to 7.5 %.Chromatographic analysis of urine indicated the presence of prothiofos oxon, O-ethyl phosphoric acid and 2, 4-dichlorophenole as main degradation products of prothiofos in free and conjugated form.     

Dissipation of pendimethalin in the soil of field pea (Pisum sativum L.) and detection of terminal residues in plants

Dissipation of pendimethalin in the soil of field peas (Pisum sativum L.) at 0 to 110 days, and terminal residues in green and mature pea were studied under field conditions. Pendimethalin was applied as pre-emergence herbicide at 750, to 185 g a.i. ha^?1 in winter, in field peas. Dissipation of pendimethalin in the soil at 0 to 110 days followed first-order kinetics showing a half-life of 19.83 days averaged over all doses. Low pendimethalin residues were found in mature pea grain (0.004, 0.003, <0.001 μg g^?1), and straw (0.007, 0.002, <0.001 μg g^?1) at 750, 350 and 185 g a.i. ha^?1 treatments, respectively. The study indicated that residues of pendimethalin in green and mature pea were within the prescribed MRL limits.