Harmful effects of pyrethroid ester insecticide on the male reproductive system mainly through affecting testicular function and inflammatory markers

Pyrethroid esters are widely used as insecticides worldwide. In this study, we aimed to evaluate the harmful effect of deltamethrin on the male reproductive system through the assessment of reproductive hormones, inflammatory markers, and testicular function. To achieve our aim, eighty male 7-9-week-old, Wistar rats were taken, weighed, and divided into four experimental groups. The first group was kept as a control group, and the other three groups were given deltamethrin orally at different concentrations (0.87, 8.7, and 17.4 mg/kg body weight) for nine weeks. The results indicated that deltamethrin administration associated with a significant decrease in reproductive hormones, especially FSH, LH, and significant elevation in the interleukin 2 (IL2), interleukin 6 (IL6), histamine, and cortisol levels. Also, the significance of inhibition of sperm motility and viability, decreased testis weights, sperm count, and fructose in semen were noted. These findings clarify the harmful effect of deltamethrin on the male reproductive system by producing a significant alteration in reproductive hormones, inflammatory markers as well as testicular function.     

香料烟中“溴氰菊酯”的残留降解研究

为了评价“溴氰菊酯”在香料烟中的残留降解行为,进行了连续2年“溴氰菊酯”在香料烟中的残留田间试验.检测结果表明:①2.5％“溴氰菊酯”乳油在香料烟叶中的降解符合一级动力学降解模式,其半衰期为5.80 ～ 6.19 d;②施药后15 d残留量在0.0128 mg· kg-1以下,降解率达95％以上;③按600 mL· hm-2喷施2次和3次2.5％“溴氰菊酯”乳油,15 d后采收,香料烟鲜烟叶中的残留量为＜0.01～ 0.4703 mg· kg -1;④2年的气候条件虽然有差异,但“溴氰菊酯”在香料烟中的残留降解行为基本一致.在香料烟的生长过程中,按照推荐用量,在15 d安全间隔期以上,连续3次施用2.5％“溴氰菊酯”乳油,“溴氰菊酯”的残留量不超过0.05 mg· kg-1.     

Effectiveness of insecticide-incorporated bags to control stored-product beetles

Adults of seven stored-product beetle species were exposed on the inside and outside surfaces of polypropylene polymer bags incorporated with the insecticide deltamethrin (approx. concentration of 3000 ppm; ZeroFly^® Storage Bags (3 g/kg). Beetles were exposed for 60, 120, and 180 min, and 1, 3 and 5 days on the same treatment arenas, and after the 5 d interval the insects were removed and placed in untreated arenas for 5 more days. All Trogoderma variable (Ballion), the warehouse beetle, Prostephanus truncatus (Horn), the larger grain borer, Rhyzopertha dominica (F.), the lesser grain borer, and Tribolium castaneum (Herbst), the red flour beetle, were knocked down on the outside and inside surfaces of the bag after one hour of exposure. Mortality of T. variable, P. truncatus, and R. dominica increased during the exposure period, with generally lower mortality on the inside versus the outside of the bag after either 3 or 5 days of continual exposure. However, maximum mortality of T. castaneum, the red flour beetle, was only 5.6 ± 3.4% after 5 days of exposure. While it took longer for 100% knockdown of Sitophilus oryzae (L.), the rice weevil, compared to the above species, all S. oryzae were dead after 5 d of exposure on both surfaces. In contrast, after 5 days knockdown of Sitophilus zeamais (Motschlulsky), the maize weevil, did not exceed 30% and there was no mortality. After the Sitophilus species were transferred to untreated arenas, knockdown of all species decreased and mortality increased, indicating delayed mortality and no recovery from knockdown. Mortality of Dermestes maculatus (DeGeer), the hide beetle, did not exceed 5.6% at any time and there was no delayed mortality, indicating a potential tolerance of this particular strain of D. maculatus used in the study. Our results show that the ZeroFly^® Storage Bags could effectively limit penetration of stored-product beetles through the bag into stored grains or milled grain products.     

Study on the effect of grain storage and processing on deltamethrin residues in post-harvest treated wheat with regard to baby-food safety requirements

The effects of storage intervals and of milling procedures on dissipation of deltamethrin residues in post-harvest treated wheat grain were studied with the aim to obtain scientific data on compliance of the processed products with the safety requirements concerning baby foods. The insecticide formulation was applied on stored wheat at a recommended rate of active ingredient of 0.5 mg kg^-1 and at a higher rate of 4 mg kg^-1, performing the highest protective effect. The dissipation of residues and their distribution in different fractions of the milled grain were studied after various storage intervals, from 7 to 270 days after treatment. Eight fractions—bran, semolina, three types of groats, and three types of flour—were collected after milling of grain and analysed for determination of pesticide residues. The residues were determined by gas chromatography characterized by the limit of determination of 0.005 mg kg^-1, low enough for enforcement of the maximum residue level of 0.01 mg kg^-1 established by the European Commission Directive for any pesticide in cereal-based foods. Deltamethrin applied post-harvest on wheat as grain protectant was distinguished by low rate of degradation on the grain under practical storage conditions. One hundred and eighty days after treatment at an application rate of 0.5 mg kg^-1, the residues were between 0.03 and 0.2 mg kg^-1 in the various types of flour. Two hundred and seventy days after treatment at a rate of 4 mg kg^-1, the residues in the flour were in the range of 0.4-1.5 mg kg^-1.     

Potential dermal exposure to deltamethrin and risk assessment for manual sprayers: influence of crop type

A comparison of the Potential Dermal Exposure (PDE) of workers to the insecticide deltamethrin was made as a function of crop type, in small agricultural production units in Argentina. Seven experiments were done with two different crops (maize and broccoli, treated area between 600 and 1000 m(2)) with three different operators under typical field conditions using a lever operated knapsack. The methodology is based on the whole body dosimetry technique, presenting separately the data for mixing/loading and application activities. These results indicate a higher concentration of pesticide in lower body sections for broccoli and a wider distribution for maize. The risk inherent in these agricultural procedures is estimated through Margin of Safety (MOS) values and was found to be generally safe. Preliminary results of a mass balance distribution of the pesticide between crop, soil and operator are also presented.     

应用臭氧降解敌敌畏、溴氰菊酯的试验研究

以敌敌畏、溴氰菊酯为研究对象，利用不同质量浓度的臭氧水，采用不同作用时间，进行了敌敌畏，溴氰萄酯降解实验。试验结果表明，臭氧可有效降解农药，试验前10分钟即可降解80％以上。     

Layer-by-layer self-assembly CdTe quantum dots and molecularly imprinted polymers modified chemiluminescence sensor for deltamethrin detection

A novel chemiluminescence sensor for determination deltamethrin was firstly reported based on CdTe quantum dots and deltamethrin imprinted polymers by layer-by-layer assembly modified on the surface of slide glass, whose shape was the same as the bottom of 96 well micro-plate. The binding characteristic of the imprinted polymers to deltamethrin was evaluated by equilibrium binding experiments and the morphology was studied by scanning electronic microscope. Scatchard analysis was carried out to estimate the binding parameters of the imprinted polymers. The water-soluble TGA-capped CdTe quantum dots were prepared. NaHTe was used as the Te precursor for CdTe quantum dots synthesis. Under the optimum conditions, the chemiluminescence intensity had a linear relationship against the concentration of deltamethrin over the range of 0.053-46.5 μg mL⁻¹ with a lower detection limit of 0.018 μg mL⁻¹. The regression equation was ΔI = 2225 + 107c (c: μg mL⁻¹) with a correlation coefficient of 0.9973. The relative standard deviation was 4.7%. The presented method was applied successfully to the determination of deltamethrin in real samples with satisfactory results.     

突发溴氰菊酯污染的应急处理工艺中试研究

溴氰菊酯是净水厂原水突发水质污染的高风险物质之一。通过中试研究了原水突发溴氰菊酯污染的应急处理工艺。结果表明,仅靠常规工艺难以有效应对原水突发溴氰菊酯污染;向原水中投加粉末活性炭(PAC)与强化常规处理工艺联用可有效去除水中溴氰菊酯,保证处理后水质达到生活饮用水卫生标准要求;炭液混合和混凝澄清阶段是溴氰菊酯去除的主要阶段,去除率为42%～98%;炭砂滤柱通过吸附截留水中载有溴氰菊酯的微小絮体颗粒,实现进一步去除水中溴氰菊酯的目的;颗粒炭滤柱作为安全余量,是水质安全保障的最后关口。基于中试结果,给出了应对原水突发溴氰菊酯污染时PAC对溴氰菊酯的吸附能力。     

Simplified pesticide multiresidues analysis in fish by low-temperature cleanup and solid-phase extraction coupled with gas chromatography/mass spectrometry

A simple and fast method for the simultaneous analysis of thiobencarb, deltamethrin and 19 organochlorine pesticide residues in fish by gas chromatography–mass spectrometry was investigated in this study. Samples are extracted with acetonitrile. Most of lipids in the extract are eliminated by low-temperature cleanup, prior to solid-phase extraction cleanup. The lipids extracted from the fish samples were easily removed without any significant losses of the pesticides. Aminopropyl (NH₂) cartridge was effective to eliminate the remaining interference. Spiked experiments were carried out to determine the recovery, precision and limits of detection (LODs) of the method. The method detection limits ranged from 0.5 μg kg⁻¹ to 20 μg kg⁻¹, whilst recoveries of the pesticides were in the range of 81.3–113.7% with relative standard deviations ?13.5% at a spiked concentration of 0.05 mg kg⁻¹, 0.02 mg kg⁻¹ and 0.1 mg kg⁻¹. The newly developed method is demonstrated to give efficient recoveries and LODs for detecting pesticide multiresidues in fish.     

Efficacy of five insecticides for the control of Trogoderma granarium Everts (Coleoptera: Dermestidae) larvae on concrete

Small and large larvae of the khapra beetle, Trogoderma granarium Everts were exposed for 1, 3, and 7 d on concrete that was treated with chlorfenapyr at 0.055 mg active ingredient (a.i.)/cm² and 0.11 mg (a.i.)/cm², deltamethrin at 0.0025 mg (a.i.)/cm² and 0.005 mg (a.i.)/cm², pirimiphos-methyl at 0.025 mg (a.i.)/cm² and 0.05 mg (a.i.)/cm², pyriproxyfen at 0.000115 mg (a.i.)/cm² and 0.00023 mg (a.i.)/cm², and spinosad at 0.05 mg (a.i.)/cm² and 0.1 mg (a.i.)/cm². Then, the survived individuals were transferred on untreated concrete for 7 more days and the delayed mortality of small or large larvae was evaluated. Concerning the immediate mortality of small larvae, chlorfenapyr was the most effective among the insecticides tested causing 70% immediate mortality after 7 d of exposure at the higher dose. The other insecticides provided similar mortality levels with the exception of pyriproxyfen which was not effective, for any of the combinations tested, as mortality did not exceed 4.4%. Delayed mortality for chlorfenapyr was also high reaching 76% at 7 d of exposure at the higher dose. Pirimiphos-methyl and deltamethrin gave similar results, indicating that for these two insecticides there is also a noticeable delayed effect. For pyriproxifen and spinosad, the delayed mortality was low. Large larvae were by far more tolerant than small ones in all dose-insecticide-exposure combinations examined for both immediate and delayed mortality counts. The results of the present study show that none of the insecticides were able to totally control T. granarium larvae, illustrating the difficulties in controlling this species, with dose rates that are usually effective for other major stored product beetle species.