Excretion and residues of the herbicides benzoylprop-ethyl flamprop-isopropyl and flamprop-methyl in cows,pigs and hens

Two wild oat herbicides, benzoylprop-ethyl and flamprop-methyl were administered to lactating cows at low dose levels (0.3–3.0 mg/kg in total diet) and the excretion of total metabolites in milk, urine and faeces was measured. Total residues in tissues were also determined. Similarly a third and related herbicide flamprop-isopropyl was fed to cows, pigs and hens (at 0.5 mg/kg in total diet) and the residues were determined in excreta and tissues, including eggs. The amounts of the compounds fed were equivalent to approximately 10–300 times the total residue found in cereal treated in the field. Residues in milk in most cases were well below 0.001 mg/kg; in muscle samples <0.003 mg/kg; and in eggs, 0.0008 mg/kg, decreasing by 50% in approximately 3 days to 0.0001 mg/kg 4 days after the termination of treatment. Elimination of the herbicides from the animals was rapid in every case and this, together with the low residue levels, was attributed to very efficient metabolic de-esterification to the parent carboxylic acid metabolites (benzoylprop and flamprop). These metabolites possess physical properties ideally suited for excretion via the kidneys and bile into urine and faeces and, conversely, unsuited for transport into milk and eggs.     

Excretion and residues of the pyrethroid insecticide cypermethrin in lactating cows

Two radiolabelled forms of racemic [¹⁴C]cypermethrin (¹⁴C at the benzylic carbon or at C-1 of the cyclopropane ring) were separately administered twice daily to lactating cows in portions of the feed. The amounts dosed were equivalent to 0.2, 5 and 10 μg of cypermethrin per g of feed. The radioactivity eliminated in the milk indicated that the ingestion and elimination of radioactivity were in balance at about day 4 after the start of dosing. Urine and faeces were equally the major routes of elimination, and only a fraction of a percent of the dose appeared in the milk. The residue in the milk was unchanged cypermethrin and was found at a concentration that was proportional to the dose. At the high cypermethrin intake of 10 μg g^?1 of diet, the residue in the milk was 0.03 μg g^?1. Concentrations of residues in the tissues, measured after 7, 20 or 21 days of treatment, were low and in the order: liver>kidney>renal fat>subcutaneous fat>blood>muscle>brain. The major residue in the liver and kidney of a cow that received 10 μg of cypermethrin per g of diet was N-(3-phenoxybenzoyl)glutamic acid. Other conjugates of 3-phenoxybenzoic acid and of 3-(4-hydroxyphenoxy)benzoic acid (unidentified, with the exception of the glycine conjugate) were also present. The residue in fat (about 0.1 μg g^?1 from an intake of 10 μg g^?1 of feed) consisted mainly of cypermethrin.     

Metabolic fate of [14C]endrin in bluegill fish

Bluegill absorbed 85% of 1 ppb of endrin from water within 48 hr under static exposure conditions. The absorbed radiocarbon was eliminated linearly with a half-life of about 4 weeks. Analyses of eliminated radioactivity revealed only conjugated metabolites. 12-anti-Hydroxyendrin and 12-syn-hydroxyendrin were tentatively identified by cochromatography using thin-layer chromatography/autoradiography and gas chromatography. These metabolites were also present as conjugates in the fish organs. Seventy-three percent of the absorbed radioactivity recovered from fish extracts was in the form of unchanged endrin.     

The dietary toxicity of flocoumafen to hens: Elimination and accumulation following repeated oral administration

In a dietary toxicity study, laying hens received a diet containing the rodenticide flocoumafen at concentrations of 1.5, 5, 10 and 50 mg kg^?1 for five consecutive days. The LC₅₀ at termination following a 28-day observation period was 16.4 mg kg^?1. Livers of birds which received doses of flocoumafen between 5 and 50 mg kg^?1 had concentrations of flocoumafen (1.5 nmol g^?1) that were independent of dose. The data indicate the presence in hen liver of a saturable high-affinity flocoumafen binding site with similar characteristics and capacity to that of the quail and rat. Residues of flocoumafen in samples of breast and leg muscle were low in all exposure groups. Higher, dose-related residues were found in samples of abdominal fat and skin-associated fat and there was a clear demonstration of the transfer of dose-related residues into eggs. In a separate study in which hens were dosed with [¹⁴C]flocoumafen for five consecutive days at a daily rate of 1 and 4 mg kg^?1 body weight, the majority (68 %) of the daily radioactive dose was eliminated over the following 24 hours via excreta. Residues in liver at death or when killed accounted for < 1 % of the cumulative administered radioactivity. Residues in eggs were located primarily in the yolk with maximum concentrations 1.0 mg kg^?1 or 0.18% of the low dose; 2.1 mg kg^?1 or 0.06% of the high dose as [¹⁴C]flocoumafen equivalents were observed at 10 days after start of dosing. Some 40 % of the total activity in the yolk was unchanged flocoumafen.     

Residues in blackcurrants,fodder peas,spinach and potatoes treated with sublethal doses of 2,4,5-T to simulate wind drift damage

Blackcurrants, treated with 0.1 kg of 2,4,5-T ha^?1 (as esters of mixed C₄–C₆ alcohols; ‘Tormona 80’), contained 0.1 mg of 2,4,5-T residues kg^?1 in the berries at ripeness 29 days after treatment. Total residues in the berries were not reduced during growth and ripening, although the residue concentrations declined in the same period due to growth dilution. In spinach leaves from old plants, treated with 0.1 kg ha^?1, 0.05 mg of 2,4,5-T kg^?1 was found 14 days after treatment. Fodder peas showed no residues (< 0.002 mg kg^?1) at harvest 62 days after treatment with 2,4,5-T esters. After application of 0.1 kg ha^?1 on potato plants, the disappearance of 2,4,5-T was rapid during the first month, but residues were translocated into the tubers and reached a constant level of 0.02 mg kg^?1 after 1 month until harvest at 108 days after treatment. In all crops, visible effects were observed after treatment with 0.1 kg ha^?1. After the application at 0.01 kg ha^?1, phytotoxic effects were observed only in blackcurrants, but negligible residues were found in all the test crops.     

二氰蒽醌和吡唑醚菌酯在枣中的残留行为及膳食摄入风险评估

建立了采用高效液相色谱-紫外检测器(HPLC-VWD)检测二氰蒽醌和吡唑醚菌酯在枣中残留量的分析方法,研究了两者在枣中的消解动态、最终残留水平以及膳食摄入风险。样品加盐酸后,用乙腈匀浆提取,Florisil柱净化,HPLC-VWD检测,外标法定量。运用慢性膳食摄入风险(%ADI)和急性膳食摄入风险(%ARf D)对二氰蒽醌和吡唑醚菌酯在不同人群的急(慢)性膳食摄入风险进行了估计。结果表明:在0.1~5 mg/kg添加水平下,二氰蒽醌和吡唑醚菌酯在枣中的平均回收率在76%~112%之间,相对标准偏差(RSD)在1.1%~9.6%之间;两种农药在枣中的定量限(LOQ)均为0.1 mg/kg。消解动态试验结果表明:二氰蒽醌和吡唑醚菌酯在枣中的消解动态符合一级动力学方程,其消解半衰期分别为1.5~2.5 d和12.4~18.4 d。最终残留试验结果表明:二氰蒽醌和吡唑醚菌酯在枣中的最终残留量分别为0.1~3.83和0.1~3.07 mg/kg。对2~6、7~14、18~30和60~70岁4类人群进行急(慢)性膳食摄入风险评估结果显示:施药后7 d,枣中吡唑醚菌酯的残留量对2~6岁的幼儿存在不可接受的急性膳食摄入风险,其他人群的急(慢)性膳食摄入风险较低;二氰蒽醌在施药后7、14和21 d,吡唑醚菌酯在14和21 d对4类人群的急(慢)性膳食摄入风险均在可接受范围之内。本研究结果表明:采用16%唑醚·氰蒽醌水分散粒剂防治枣树炭疽病,用药量为2.67 g/kg,施药间隔期7 d,最大施药次数3次,采收间隔期14 d,收获期的枣对各类人群的膳食摄入风险较小。     

Residues of clenpirin [2-(3,4-dichiorophenylimino)-l-n-butyl pyrrolidine] in the fatty tissues of steers and in butter fat

A series of trials in which cattle were either treated dermally or dosed orally with clenpirin [2-(3,4-dichlorophenylimino)-l-n-butyl pyrrolidine] was undertaken. Tissue fat from steers and butter fat from milking cattle were sampled and residue levels determined colorimetricaliy. Residues following a single application of clenpirin (9 litres/beast at 0.25% w/v) reached an average maximum of 2.0 mg/kg in body fat and then declined to 0.2 mg/kg after 14 days. Multiple applications (9 litres/beast at 0.25% w/v) resulted in a progressive buildup of residues in body fat to about 30 mg/kg after 4 treatments. When steers were dosed orally with technical clenpirin at 700 mg/beast/day for 15 days the average fat level reached 0.7 mg/kg. In a series of trials with milking cattle a single dermal exposure (0.23-0.3% w/v aqueous emulsion) yielded residues in butter fat ranging from 1 5.5-51 1 mg/kg at the first sampling 5 h after treatment. Six days later these had declined to about 0.8 mg/kg.     

Residues of zeta‐cypermethrin in bovine tissues and milk following pour‐on and spray application

The depletion of zeta‐cypermethrin residues in bovine tissues and milk was studied. Beef cattle were treated three times at 3‐week intervals with 1 ml 10 kg^?1 body weight of a 25 g litre^?1 or 50 g litre^?1 pour‐on formulation (2.5 and 5.0 mg zeta‐cypermethrin kg^?1 body weight) or 100 mg kg^?1 spray to simulate a likely worst‐case treatment regime. Friesian and Jersey dairy cows were treated once with 2.5 mg zeta‐cypermethrin kg^?1 in a pour‐on formulation. Muscle, liver and kidney residue concentrations were generally less than the limit of detection (LOD = 0.01 mg kg^?1). Residues in renal‐fat and back‐fat samples from animals treated with 2.5 mg kg^?1 all exceeded the limit of quantitation (LOQ = 0.05 mg kg^?1), peaking at 10 days after treatment. Only two of five kidney fat samples were above the LOQ after 34 days, but none of the back‐fat samples exceeded the LOQ at 28 days after treatment. Following spray treatments, fat residues were detectable in some animals but were below the LOQ at all sampling intervals. Zeta‐cypermethrin was quantifiable (LOQ = 0.01 mg kg^?1) in only one whole‐milk sample from the Friesian cows (0.015 mg kg^?1, 2 days after treatment). In whole milk from Jersey cows, the mean concentration of zeta‐cypermethrin peaked 1 day after treatment, at 0.015 mg kg^?1, and the highest individual sample concentration was 0.025 mg kg^?1 at 3 days after treatment. Residues in milk were not quantifiable beginning 4 days after treatment. The mean concentrations of zeta‐cypermethrin in milk fat from Friesian and Jersey cows peaked two days after treatment at 0.197 mg kg^?1 and 0.377 mg kg^?1, respectively, and the highest individual sample concentrations were 2 days after treatment at 0.47 mg kg^?1 and 0.98 mg kg^?1, respectively. © 2001 Society of Chemical Industry     

The metabolism of tefluthrin in the goat

A goat was dosed orally with [¹⁴C]tefluthrin, twice daily for 4 days, at a rate equivalent to 10.9 mg kg^?1 in its diet. Within 16 h of the final dose, 70.1% of the dose had been excreted (urine 41.4%, faeces 28.7%). Extensive metabolism occurred in the goat by ester cleavage and oxidation at a variety of positions on the molecule. Low radioactive residues were detected in the milk (0.076 mg kg^?1), fat (0.076 mg kg^?1) and muscle (0.016 mg kg^?1), with tefluthrin as the largest individual component of the residue (milk 66.5%, fat 76.7%, muscle 34.2%). Higher residues were present in the kidney (0.3 mg kg^?1) and liver (1.0 mg kg^?1) and only a small percentage of this residue was due to tefluthrin (kidney 3.4%, liver 6.1%). The remainder of the residue in the kidney and liver was a complex mixture of metabolites. Most of the kidney metabolites were identified, but a high proportion of the liver residue was due to six unidentified polar compounds.     

烯啶虫胺在水稻和稻田环境中的残留及消解动态

采用高效液相色谱-紫外检测器(HPLC-UVD)测定了烯啶虫胺在稻田水、土壤、水稻植株和糙米样品中的消解动态及最终残留。田水样品用二氯甲烷萃取;土壤样品用水提取后经二氯甲烷萃取;水稻植株和糙米样品依次用水、丙酮提取,提取液经液液萃取及柱层析净化;HPLC-UVD检测。当烯啶虫胺在田水和土壤中的添加水平为0.1~5 mg/L和0.1~5 mg/kg,在植株和糙米中的添加水平为0.2~5 mg/kg时,其平均添加回收率在77.2% ~100.3%之间,相对标准偏差 (RSD)在1.9% ~12.9%之间。烯啶虫胺在稻田水、土壤、植株和糙米中方法的定量限(LOQ)分别为0.1 mg/L和0.1、0.2、0.2 mg/kg,检出限(LOD)分别为0.04 mg/L和0.04、0.08、0.08 mg/kg。温室模拟消解动态试验结果显示,以推荐使用高剂量的20倍(有效成分1 500 g/hm2) 施药,烯啶虫胺在稻田水、土壤以及水稻植株中的消解动态规律均符合一级动力学方程,其半衰期分别为0.58、3.31及2.70 d,消解速率较快。最终残留试验表明,于大田分蘖期按推荐使用高剂量的1.5倍(有效成分112.5 g/hm2)分别施药3次和4次,间隔期为7 d,距最后一次施药7 d后采样,糙米中烯啶虫胺的残留量均低于LOD值(0.08 mg/kg)及日本规定的最大残留限量(MRL)值(0.5 mg/kg)。     

The metabolic fate in rats of the pyrethroid insecticide WL85871, a mixture of two isomers of cypermethrin

The metabolism of the pyrethroid insecticide WL85871, labelled in the alcohol moiety, has been studied in male and female Wistar rats at a dose of ca 2 mg kg^?1. The compound was rapidly broken down and the radioactivity was mainly eliminated in the urine as the sulphate conjugate of 3-(4-hydroxyphenoxy)benzoic acid (40% of the dose). Some hydroxylation occurred before ester cleavage. Approximately 20% of the ingested compound was not absorbed and was eliminated unchanged in the faeces. There was no evidence for any racemisation of the chiral centres of WL85871 either in the intestine, the faeces or in fat. The small proportion of the dose stored in adipose tissue was eliminated with biphasic kinetics (t½ values, 2–3 days and 17–26 days). The t½ values for skin were, respectively, 2 days and 40 days. As the residue in fat depleted between 3 and 40 days, an increasing proportion (from 28% to 48%) was present as a lipophilic metabolite of WL85871, or of 3-phenoxybenzoic acid, probably a mixture of 3-phenoxybenzoyl diacyl glycerols.     

A barn owl feeding study with [14c]flocoumafen-dosed mice: Validation of a non-invasive method of monitoring exposure of barn owls to anticoagulant rodenticides in their prey

A study was carried out to assess the feasibility of monitoring the exposure of barn owls (Tyto alba) to an anticoagulant rodenticide, flocoumafen, by analysis of residues in regurgitated pellets following consumption of flocoumafen-contaminated mice. Mice were fed on a diet containing [¹⁴C]flocoumafen, equivalent to 12 mg kg^?1, and killed 24 h later. A single [¹⁴C]flocoumafen-contaminated mouse was fed to each of four captive barn owls, equivalent to 0·11-0·23 mg kg^?1 per bird, followed on seven successive days by control diet (i.e. undosed mice). The [¹⁴C]flocoumafen dose was eliminated by the owls over the eight-day period in pellets (44%, range 35–55%) and faeces (18%, range 11–21%), with the highest residues being observed in samples from the first 24-h period. Further detailed analysis of the pellets confirmed that flocoumafen residues in the first-day pellets represented 15% (range 8–26%) of the original flocoumafen residues ingested by the barn owls. Calculations based on these data and typical flocoumafen residues in live captured rodents (following baiting) confirm that pellet residue analysis is a sensitive and appropriate method for the non-invasive monitoring of exposure of barn owls to flocoumafen. There were no symptoms of anticoagulant poisoning in any of the birds; two of the birds were successfully paired the next season and produced fledgelings.     

Synthesis and confirmation of structure of four mammalian metabolites of dieldrin and endrin

The first syntheses of syn-12-hydroxydieldrin, syn-12-hydroxyendrin and anti-12-hydroxyendrin have been accomplished by debenzoylation and epoxidation of three isomeric adduction products of hexachlorocyclopentadiene and 1,7,7-trinorborna-2,5-dien-7-yl benzoate. A third known metabolite of endrin, 12-ketoendrin, and a putative metabolite of dieldrin, 12-ketodieldrin, were prepared from the corresponding alcohols by oxidation with chromium trioxide. Characterisation of the three debenzoylated intermediates as syn-12-hydroxyaldrin, and syn- and anti-12-hydroxyisodrin constitutes the first syntheses of these three possible metabolites of aldrin and isodrin.     

啶酰菌胺在南瓜、芦笋、山楂、芒果和木瓜上的膳食摄入风险评估

为明确啶酰菌胺在南瓜、芦笋、山楂、芒果和木瓜上使用可能产生的膳食摄入风险,通过进行规范田间残留试验,检测了南瓜、芦笋、山楂、芒果和木瓜中啶酰菌胺的最终残留量,结合国内和国际两种膳食消费量数据,评估了啶酰菌胺的长期膳食摄入风险,并就两种方法的评估结果进行了比较分析。样品采用QuEChERS方法前处理,液相色谱-串联质谱 (LC-MS/MS) 定量分析。结果表明:南瓜在0.01、0.1和3 mg/kg,芦笋在0.01、0.1和20 mg/kg,山楂在0.01、0.1和60 mg/kg,芒果在0.01、0.1和4 mg/kg,木瓜在0.01、0.1和10 mg/kg添加水平下,啶酰菌胺在空白样品中的平均回收率为79%~101%,相对标准偏差为2%~14%。采用 “中国居民营养与健康状况调查报告” 的膳食消费数据,计算得啶酰菌胺针对普通人群的国家估算每日摄入量 (NEDI) 为0.707 5 mg/(kg bw),风险商 (RQ) 为28.1%;采用世界卫生组织 (WHO) 提供的每种农产品的单独膳食量进行计算,啶酰菌胺的每日摄入量为0.128 2 mg/(kg bw),风险商 (RQ) 为5.1%。两种方法的评估结果均表明啶酰菌胺对一般人群的健康不会产生不可接受的风险,然而,采用不同膳食消费数据进行计算会导致风险评估结果存在较大差异,其原因主要是由于中国所采用的膳食消费数据是作物分类基础上的数据,而不是具体某种农产品的单独消费量,因而易导致中国的膳食摄入风险评估结果过于保守。因此建议相关部门进一步完善居民的营养与健康状况调查监测工作,提供具体到每一种农产品的膳食消费数据,以便于科学评价农药对人体健康的风险。     

Residues of organochlorine pesticides in broilers from feed fortified with known levels of these compounds

p, p'-DDT, HEOD, endrin, heptachlor epoxide, hexachlorobenzene and lindane were fed in combination to day-old broiler chickens at levels of 0.05, 0.15 and 0.30 part/million in the feed, for a period of about 7 weeks. Birds were killed at regular intervals and samples of abdominal fat and other tissues examined for residues of the chlorinated pesticides by gas-liquid chromatography. The lipid content of each sample was determined and the residue levels calculated for the whole tissue and also for the fat contained in the sample. At the end of the 7 weeks (when in practice broilers are slaughtered) residues were highest for heptachlor epoxide, followed by hexachlorobenzene, HEOD, DDT (total), endrin, and lindane. Heptachlor epoxide residue levels in fat were 13 times the levels in the feed, for lindane the ratio was 3.3. Fat residues of each pesticide reached a plateau level relatively quickly, and these levels were proportional to the fortification rates in the feed. HEOD and p, p'-DDT alone were fed to separate groups of birds. No differences in residue build-up of these compounds were found between these groups and the groups that had received these compounds in combination with the other pesticides. The total amounts of each pesticide in the tissues were reduced when the meat was fried, probably by loss of fat during preparation and frying. For p, p'-DDT and heptachlor epoxide also smaller residue were observed in the remaining fat after frying.     

贵州地区茶叶及茶汤中氯氰菊酯残留量检测及其摄入风险分析

采用气相色谱建立了茶叶样品中氯氰菊酯残留量检测方法;通过对贵州省市售茶叶样品中氯氰菊酯的残留情况进行抽检,以了解其市售茶叶的安全性;通过田间试验制备浸泡实验用茶叶样品,设计正交实验研究了影响茶汤中氯氰菊酯浸出率的因素。结果表明,市场抽检茶叶样品中氯氰菊酯残留量平均值为0.919 mg/kg,最高残留量为1.52 mg/kg,低于茶叶中氯氰菊酯的最大残留限量(MRL)标准20 mg/kg;正交实验表明,浸泡次数和浸泡时间是影响氯氰菊酯浸出率的主要因素,茶汤中氯氰菊酯的最高浸出率为5.76%。按人均最高泡茶用量13 g/d计算,由饮茶而进入人体 的氯氰菊酯的最大量为1.5×10-2 mg/d,按氯氰菊酯每日最大允许摄入量(ADI)为0.05 mg/kg bw、 平均体重60 kg计,则其安全系数(K)为200。     

The estimation of residue levels of promacyl and its metabolites in beef tissue and fat by high-performance liquid chromatography with electrochemical detection

A method is described for the estimation of residues of the carbamate insecticide promacyl [5-methyl-m-cumenyl butyryl(methyl)carbamate] and its metabolites that are hydrolysable to isothymol (m-cymen-5-ol), using high-performance liquid chromatography with electrochemical detection to determine the isothymol. Clean-up of samples relied on the steam volatility of phenols. Recoveries at the 0.1 mg kg^?1 level varied from 72–88% for fat tissue and 81–91% for liver. The limits of detection were found to be 0.01 mg kg^?1 for and 0.02 mg kg^?1 for liver. A comparative study of the chromatography of sample extracts using both ultraviolet detection and electrochemical detection showed a substantial decrease in the level of interfering co-eluates in the latter method. A field trial, involving a single spray application of the formulated acaricide on milking cattle, revealed residues in the butter fat comparable with those found in a previous investigation.     

嘧霉胺在蓝莓中的残留行为及膳食风险评估

为明确嘧霉胺在蓝莓上施用后可能产生的膳食暴露风险,通过规范的田间残留试验,检测了蓝莓中嘧霉胺的残留量,结合GEMS/FOOD中关于中国各年龄段居民97.5%位点的浆果类农产品膳食消费量及体重调查数据、每日允许摄入量(ADI),评估了嘧霉胺对中国各消费人群的长期膳食摄入风险。结果表明：在0.01～1 mg/kg添加水平范围内,嘧霉胺的平均回收率在97%～100%之间,相对标准偏差(RSD)在4.5%～12%之间;嘧霉胺在蓝莓中的检测方法定量限(LOQ)为0.01 mg/kg。露地栽培模式下,嘧霉胺在蓝莓中的消解速率符合一级反应动力学方程,消解半衰期为3.2 d。嘧霉胺按有效成分360 g/hm²施药2次,每次间隔7 d,药后3、5、7、10 d时蓝莓中嘧霉胺的残留量为0.18～1.54 mg/kg。膳食风险评估表明,在膳食消费量97.5%位点处,蓝莓中嘧霉胺残留对各消费人群长期膳食摄入风险的贡献率小于0.1%,说明通过蓝莓摄入嘧霉胺残留对人体产生的长期膳食摄入风险较小。     

豆瓣菜中啶酰菌胺残留及膳食摄入风险评估

为评价啶酰菌胺在豆瓣菜生产上应用的安全性，采用QuEChERS方法进行样品前处理，液相色谱-串联质谱 (LC-MS/MS) 进行定量分析，检测了豆瓣菜中啶酰菌胺的最终残留量，对2种膳食食谱下的长期摄入风险进行了比较分析。结果表明，在添加水平范围内，在豆瓣菜空 白样品中添加啶酰菌胺的平均回收率为89%~100%，相对标准偏差为5%~12%。GAP条件下，最终残留量为0.16~37.1 mg/kg。普通人群啶酰菌胺的国家估计每日摄入量 (NEDI) 为1.215 1 mg/(kg bw)，风险商为48.2%，表明其对一般人群健康产生的风险是可接受的，同时，使用WHO提供的单独每种农产品膳食量进行计算，啶酰菌胺每日摄入量为0.083 0 mg/ (kg bw)，风险商为3.3%。经过对比分析，推荐使用WHO提供的膳食食谱数据进行长期膳食风险评估。     

马拉硫磷在西葫芦中的残留行为及膳食摄入风险评估

利用气相色谱-火焰光度检测器 (GC-FPD) 测定了马拉硫磷在西葫芦中的残留量,根据2016年湖南、山东、北京、安徽、山西和黑龙江6地马拉硫磷在西葫芦中的规范性残留试验,对中国各类人群和不同作物中的马拉硫磷进行了膳食风险评估。样品用乙腈提取,丙酮置换乙腈后,GC-FPD检测。结果表明:在0.02~8.0 mg/kg添加水平下,马拉硫磷在西葫芦中的回收率在88%~109%之间,相对标准偏差 (RSD) 为5%,定量限 (LOQ) 为0.02 mg/kg。湖南和山东的消解动态试验结果显示,马拉硫磷的半衰期为2.74~4.65 d,属于易降解农药;6地的最终残留试验结果表明,距最后一次施药3、5、7 d后,西葫芦中马拉硫磷的最终残留量在 < 0.02~0.049 mg/kg之间。针对西葫芦的膳食风险评估结果显示,中国各类人群对马拉硫磷的国家估计每日摄入量 (NEDI) 为0.115~0.207 μg/(kg bw·d),风险商值 (RQ) 为0.000 4~0.000 7;全膳食暴露风险评估结果显示,马拉硫磷在各类食物中的NEDI值为82.251 μg/(kg bw·d),RQ值为0.275 1,表明马拉硫磷在西葫芦中的长期膳食摄入风险较低。推荐中国马拉硫磷在西葫芦上的最大残留限量值 (MRL) 为0.1 mg/kg,可确保中国西葫芦的食用安全性。