Determination of chlorothalonil residues in coffee

Coffee beans were treated with the fungicide chlorothalonil (2,4,5,6‐tetrachloro‐1,3‐benzene‐dicarbonitrile) and the residues were determined by high‐performance liquid Chromatograph (HPLC). Several techniques including Soxhlet extraction (SE), microwave‐assisted extraction (MAE) and accelerated solvent extraction (ASE) were compared for the extraction of residues. A column clean‐up procedure was developed to remove the co‐extractives in the extract before HPLC analysis. The overall mean recoveries from extracts obtained by SE, MAE and ASE were 89.2 ±3.9, 88.4 ±1.9 and 82.8 ±0.3, respectively. The results show that MAE followed by HPLC is a viable alternative to the commonly used SE and gas Chromatographic analysis for the determination of chlorothalonil in coffee.     

Toxicity,degradation and analysis of the herbicide atrazine

Excessive use of pesticides and herbicides is a major environmental and health concern worldwide. Atrazine, a synthetic triazine herbicide commonly used to control grassy and broadleaf weeds in crops, is a major pollutant of soil and water ecosystems. Atrazine modifies the growth, enzymatic processes and photosynthesis in plants. Atrazine exerts mutagenicity, genotoxicity, defective cell division, erroneous lipid synthesis and hormonal imbalance in aquatic fauna and nontarget animals. It has threatened the sustainability of agricultural soils due to detrimental effects on resident soil microbial communities. The detection of atrazine in soil and reservoir sites is usually made by IR spectroscopy, ELISA, HPLC, UPLC, LC–MS and GC–MS techniques. HPLC/LC–MS and GC–MS techniques are considered the most effective tools, having detection limits up to ppb levels in different matrices. Biodegradation of atrazine by microbial species is increasingly being recognized as an eco-friendly, economically feasible and sustainable bioremediation strategy. This review presents the toxicity, analytical techniques, abiotic degradation and microbial metabolism of atrazine.     

The effect of imazethapyr on soil microbes in soybean fields in northeast China

Large quantities of herbicides are used on agricultural soils, but the effects of herbicides on the structure of the soil microbial community have not been well investigated. In this study, soil from three soybean fields was investigated. The herbicide imazethapyr was applied in one year to soil 1 and in two sequential years to soil 2. Control soil received no imazethapyr. Microbial biomass and community structure were characterised using chloroform fumigation–extraction and phospholipid fatty acid (PLFA) determination. The imazethapyr residue was 1.62 μ g·kg^?1 in soil 1 and 1.79 μ g·kg^?1 in soil 2. The microbial biomass carbon and total PLFAs for soil 2 were much higher than for the other soils. PLFA profiles showed that fatty acids for Gram-negative and Gram-positive bacteria, as well as total bacteria and total fungi in soil 2 were higher than in other samples. Principal component analysis of the PLFAs showed that the structure of the microbial community differed substantially among the three different soybean field soils. Application of the herbicide imazethapyr to soybean fields clearly changed the soil microbial biomass and shifted the structure of the microbial community.     

绿色食品产地土壤中PAHs测定方法研究

对绿色食品产地土壤中多环芳烃的气相色谱质谱联用分析法进行了研究。样品经索氏提取后硅胶氧化铝复合柱净化,最后用GC/MS内标法进行定性定量分析。方法相关系数除苯并(a,h)蒽的相关系数R2=0.9970外,其余目标化合物的相关系数R2均大于0.9991,各化合物线性关系良好。方法加标回收率大多在70%至90%间,各目标化合物的方法检测限为2.2～40ng/kg。     

一株除草剂氰氟草酯降解菌的分离鉴定与降解特性

氰氟草酯(Calofop-buty1)是一种芳氧苯氧羧酸酯类除草剂,其迁移、转化和分解等行为对环境及人类健康具有潜在危害.为了解其微生物代谢机制,从长期使用氰氟草酯的稻田土壤中分离到1株氰氟草酯降解菌株,命名为QDZ-B.菌株QDZ-B的16S rDNA基因序列长度为1 400 bp,在RDP数据库比对结果表明其与寡养食单胞菌属菌株的同源性最近,与模式菌株嗜麦寡养食单胞菌Stenotrophomonas maltophilia(AB008509)的同源性为99.8%.根据表型特征、生理生化特性和16S rDNA序列同源性分析,将菌株QDZ-B鉴定为寡养单胞菌属(Stenotrophomonas sp.).接种量为5%时,菌株QDZ-B在基础盐液体培养基中5 d对100 mg L-1氰氟草酯的降解率约为88.2%.菌株QDZ-B的降解效果与接种量成正相关,但接种量大于5%时,降解效率趋于平稳.菌株QDZ-B降解氰氟草酯的最适温度为30℃,最适pH为7.0.通过质谱分析鉴定了3个菌株QDZ-B降解氰氟草酯的代谢产物,分别为氰氟草酸、氰氟草酰胺和2-氟-3-对-乙氧基苯氧基苯酰胺.     

水土环境介质中阿特拉津修复过程研究进展

除草剂阿特拉津农用后的残留物会随地表径流或地下渗漏作用进入江河湖泊等自然水体,由于阿特拉津的环境内分泌干扰作用,其会造成水资源污染和水生态失衡。根据阿特拉津的生产和使用状况,将阿特拉津的污染对象分为土壤、市政污水、河流湖泊等地表水和地下水系统模块,分别阐述了这几种环境介质中阿特拉津的物理、化学和生物修复技术以及阿特拉津在修复过程中的变化特点,介绍了土壤在淋溶过程中阿特拉津的固定手段和今后污染水体中阿特拉津修复的研究重点。     

环境样品中汞形态分析技术的进展

汞的毒性、环境行为、生物有效性不仅跟其浓度有关,还决定于其化学形态,因此汞的形态分析在环境科学中具有重要意义。样品前处理几乎是汞形态分析研究中不可或缺的步骤,而色谱和光谱/质谱联用技术是目前普遍采用的分离检测方法。文章对近十年来这些方面的研究进展进行了综述,主要包括样品的前处理方法如酸/碱溶剂萃取、微波辅助萃取、固相萃取、固相微萃取、单滴微萃取、分散液液微萃取等,以及色谱（液相色谱、气相色谱）和毛细管电泳与光谱/质谱（紫外可见光谱、原子吸收光谱、原子荧光光谱、等离子体质谱等）的联用技术在汞化合物形态分析中的应用情况。最后提出今后应重点研究建立高效、简便的前处理方法,发展高分离度、高灵敏度、高速度的分离检测联用技术,以便更好地对汞的形态进行分析监测。     

Dissipation and effect of chlorophenoxy herbicide on plant pigments and carbohydrates of sunflower (Helianthus annuus L.)

The dissipation pattern of the chlorophenoxy herbicides (2,4‐D and 2,4,5‐T) residues in sunflower plants (Helianthus annuus L.) has been studied along with its effect on the changes of plant pigments (chlorophyll‐a,b, total chlorophyll, carotene and anthocyanin), sugar and starch in different parts of the plant. The residues of 2,4‐D and 2,4,5‐T remained for larger period of time (10 days) at higher concentrations than the lower concentration. The concentrations of chlorophylls and carotene were found to be reduced with the application of both 2,4‐D and 2,4,5‐T. But the chlorophyll concentrations were slowly normalized accompanied with the reduction of the herbicide residues. For anthocyanin, there was no significant effect. In case of carbohydrate, the sugar concentration was found to be raised by all doses in leaf and stem. The change in starch content in different plant parts did not follow an uniform pattern at different doses of herbicides.     

利用EIA法快速筛查垃圾焚烧飞灰和烟气中的二恶英毒性水平

基于CAPE技术公司的兔子复合克隆抗体的二恶英(PCDD/F)酶免疫分析试剂盒,建立了快速检测垃圾焚烧飞灰和烟气中PCDD/F毒性(TEQ值)的方法.试剂盒的最低检测限为3.3pg·tube-1(即3.3pgTEQ每EIA试管),线性检测范围为10～30pg·tube-1.样品经甲苯索氏抽提后过硅胶柱连接小碳柱净化处理,TCDD/F的回收率大约为50%,与原飞灰PCDD/F分布模式相比净化处理后样品中的TCDD/F含量明显降低.用净化处理后的飞灰溶液作标准溶液,绘制PCDD/F剂量-效应关系曲线,定量分析了2个飞灰样品和2个烟气样品的TEQ浓度,结果表明分析样品的TEQ实测值(HRGC/HRMS分析获得)与预测值(标准曲线计算值)的相对偏差(Rd)均小于15%,说明用该方法定量分析垃圾焚烧飞灰和烟气中PCDD/F毒性是可行的.     

四种除草剂对泥鳅红细胞遗传毒性的研究

采用红细胞微核和核异常测试法,研究了除草剂精禾草克、氟乐灵、扫茀特,2-甲-4氯钠水剂对泥鳅红细胞核的遗传毒性.结果表明,4种除草剂单独作用时均不同程度地引起微核细胞率和核异常细胞率等遗传指标的上升(P<0.05或P<0.01). 低浓度的除草剂对泥鳅红细胞的联合诱变作用比高浓度的除草剂明显.除草剂浓度与微核率或核异常率无显著相关,不表现剂量-效应关系.扫茀特的诱变效应大于其它3种除草剂.4种除草剂联合作用时具拮抗性. 图1 表5 参20     

Comparison of extraction methods for polycyclic aromatic hydrocarbon determination in sediments

Different sample preparation methods for the determination of polycyclic aromatic hydrocarbons (PAHs) in lake and river sediments were compared and evaluated. Freeze‐dried sediment materials were extracted using Soxhlet extraction, ultrasonic agitation and digestion with various solvents and solvent mixtures. Similarly, clean‐up methods using various types of sorbents for separation of PAHs tested.

The following method gives the best results for the determination of PAHs: freeze‐dried sediment samples were extracted using Soxhlet extractor with dichloromethane (6 hr, dark), extracts were cleanup using Silica gel and a mixture of n‐hexa‐ne‐dichloromethane was used for the elution of PAHs.

This method was used for the determination of 7 selected PAHs in sediment samples from Finnish lakes and Czech streams.     

Removal of pesticides from water samples by adsorption with fatty acids supported on barium sulphate

Oleic or linoleic acid supported on barium sulphate was used to remove atrazine and terbuthylazine in the range of 0.1–2.0 μg/L using spiked water samples. The sorption of atrazine depends on the stirring time and the best value is 150 min. Terbuthylazine is removed well with a stirring time of 60 min and its adsorption is about 90%. Detection of the residual pesticide in treated waters, after solid phase extraction (SPE), was carried out by GC‐MS operating in selected ion monitoring (SIM) using a calibration curve by direct injection of standard solutions of herbicide.     

High performance liquid chromatographic determination of pesticides in soluble phase and suspended phase in river water

A high performance liquid chromatographic method has been developed to determine pesticides in river water as both dissolved phase and suspended phase. The target pesticides were eight herbicides, asulam, diuron, flazasulfuron, linuron, MCPB, mecoprop, pyrazosulfuron‐ethyl and siduron, and two fungicides, oxine‐copper and thiram. The pesticides in filtered river water were extracted with styrene‐divinylbenzene copolymer and were eluted with acetonitrile. The pesticides on suspended solids were extracted ultrasonically with acetonitrile. Each eluate was concentrated and analyzed by HPLC with multiwavelength detector. Recoveries of the pesticides in the overall procedure of this method were 78–114% for filtered river water and 75–107% for suspended solids. The limits of detection in water and suspended solids ranged from 0.1 to 0.9 μg/L and 1 to 7 μg/g, respectively. Pesticide distribution between soluble phase and suspended phase in river water was measured by this method.     

固相微萃取-气相色谱/质谱联用法测定饮用水中苯类化合物

用固相微苹取(ＳＰＭＥ)－气相色谱/质谱联用法测定饮用水中苯类化合物,以１００μｍ ＰＤＭＳ(聚二甲基硅氧烷)萃取针提取、浓缩、分离与测定九种目标化合物．萃取时间经优化选定为８ｍｉｎ,而热解析时间设定为２ｍｉｎ． 本方法的相对标准偏差小于５%,线性范围宽(２０ｎｇ·ｍｌ－１－１００００ｎｇ·ｍｌ－１),多数化合物的检测限低于５μｇ·ｌ－１．饮用水样品检测显示,样品加标回收率范围在８４%至１１０%内．     

水体和甘蓝及土壤中毒死蜱残留检测方法

研究运用不同的样品前处理方式,在装配火焰光度检测器的气相色谱(GC-FPD)上检测,建立了有机磷杀虫剂毒死蜱在水样、土壤和甘蓝中的残留测定方法.研究表明,不同样品中的毒死蜱残留采用本文中介绍的前处理方法是可行的,用石油醚盐析提取和净化水样中毒死蜱,采用丙酮振荡提取甘蓝中毒死蜱,选用索氏提取法提取土壤中毒死蜱,并经液液分配净化后,采用OV-101大口径毛细管柱(30 m×0.53 mm×1.0μm),在装配火焰光度检测器(FPD和磷滤光片)的气相色谱上测定.该分析方法下,毒死蜱的保留时间为1.74 min,线性范围在1.0×10-11—1.0×10-8g之间,其线性相关系数为0.9998,最小检出量为2.0×10-12g.在设定的较低添加浓度的条件下,毒死蜱在水样、土壤与甘蓝上的添加回收率为80%—120%,变异系数均小于5%.该分析方法灵敏、准确、操作简便,适合水样、甘蓝和土壤中低浓度毒死蜱的残留检测.     

Integrating farming techniques in an ecological matrix model: Implementation on the primrose (Primula vulgaris)

Several studies have proven the importance of field margins in sustaining biodiversity and other work has been done on the effect of field management on field margin flora. However few models have been built to predict the effects of field management on the flora. Our project addresses this need for a model capable of predicting the effect of cropping techniques and their timing on the flora of field margins. Primula vulgaris is a biodiversity indicator, characteristic of undisturbed flora and found in field margins and woodlands: its population has been declining for several years. We created a temporal matrix model of P. vulgaris populations on field margins, taking into account the effects of field, field margin and roadside management based on literature and expert knowledge. We then analysed its sensitivity to demographic parameters by comparing lambda (growth rate) sensitivity and elasticity. We compared the management parameter effect using the relative growth rate of the population after 6 years of simulation. Sensitivity analysis to biological parameters showed the importance of adult survival and seed production and germination. Results show that P. vulgaris is particularly sensitive to broad-spectrum herbicides and that other management techniques like early mowing, scything and scrub-killer (diluted broad-spectrum herbicide or specific herbicide) are less aggressive. Our simulations show that management of cash crops in Brittany is too aggressive for P. vulgaris populations and that 4-5 years of grassland in the adjacent field are necessary to maintain populations.     

Environmental fate of pesticides used in Australian viticulture V. Behaviour of atrazine in the soils of the south Australian Riverland

The transport of the s‐triazine herbicide, atrazine, through the red, calcareous earth soils of the South Australian Riverland was investigated. Small, undisturbed soil cores were extracted from the inter‐row topsoil of a vineyard adjacent to the River Murray, approximately 10 km south‐west of Overland Corner, South Australia. The vines were grown in a deep (1–4 m) reddish brown, strongly alkaline, sandy loam with a low organic carbon content (<2%). Atrazine concentrations in the leachate were dependent on application rate and soil type. High application rates on subsoil gave high rates of leaching for a longer time compared to the same application rate on topsoil and/or lower application rates on either topsoil or subsoil. Overall, 37–65% of the applied atrazine was detected in the leachate from subsoil cores, 14–25% in topsoil core leachates. Small amounts of atrazine (< 10% of applied dose) were found only in the top 2 cm of the core profiles. The results suggest that this herbicide is somewhat mobile in such strongly alkaline, sandy loam soils and that the irrigated soils of this region are likely to be prone to leaching of atrazine, and therefore that groundwater supplies in this area may be at risk of contamination through use of triazine herbicides.     

In vitro degradation of the herbicide atrazine by soil and wood decay fungi controlled through Elisa technique

The interaction between atrazine, a triazine herbicide, and a series of decay fungi was characterized in terms of biodegradation of the herbicide and its influence on fungal growth. The following fungi were studied: thermophilic cellulolytic (Penicillium sp. 13) and noncellulolytic (Humicola lanuginosa sp. 5 and 12) strains isolated from self‐heated plant composts, mesophilic diphenol oxidase producing strain Mycelia sterilia INBI 2–26, white‐rot fungi Cerrena maxima, Coriolopsis fulvocinerea and Coriolus hirsutus. Competitive enzyme immunoassay was elaborated for detection of atrazine in cultural liquid. During agar plate cultivation the growth of Humicola sp. 5 was promoted by atrazine whereas the growth of Humicola sp. 12 and Penicillium sp. 13 was suppressed whereas M. sterilia INBI 2–26 was not affected by the herbicide. Neither atrazine‐accelerated nor atrazine‐depressed thermophilic strains decomposed atrazine during 21‐day cultivation according to ELISA data. In contrast, white‐rot fungi Coriolus hirsutus, Coriolopsis fuhocinerea and Cerrena maxima degraded nearly 50% of the herbicide in 5‐day submerged cultivation and 80–92% of the herbicide up to the 40th day. The soil strain M. sterilia INBI 2–26 decomposed 70% of atrazine in 17‐day cultivation. The degradation level depended of the time of atrazine introduction to the growing media. The relationships between the degree of atrazine decomposition and laccase and Mn‐peroxidase production were shown.     

环境样品前处理技术及其进展（二）

在前文中讨论了环境样品的制备、前处理的概况，以及超临界流体萃取法。本文将继续报导近年来环境样品制备与前处理领域中其他一些新技术和新方法，包括固相萃取（ＳＰＥ）、微波溶出（ＭＷＤ）和液膜萃取（ＳＬＭ）法，阐述了这些方法的基本原理、操作过程、各种实验参数的影响，及其在环境样品制备与前处理中的应用，并探讨了该领域的发展动向。