锐劲特在菜地生态系统中的残留动态研究

建立了青菜、土壤中锐劲特及其代谢物的气相色谱毛细管柱残留分析的方法。对锐劲特及其降解产物在菜地生态系统中的残留动态进行了研究,明确了锐劲特在青菜和土壤中的残留和消解情况,锐劲特在土壤中的降解半衰期为7．88d,在青菜中的降解半衰期为2．58d。     

Residues and dynamics of pymetrozine in rice field ecosystem

The fate of pymetrozine was studied in rice field ecosystem, and a simple and reliable analytical method for determination of pymetrozine in soil, rice straw, paddy water and brown rice was developed. Pymetrozine residues were extracted from samples, cleaned up by solid phase extraction (SPE) and then determined by high-performance liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS-MS). The average recovery was 81.2-88.1% from soil, 83.4-88.6% from rice straw, 87.3-94.1% from paddy water and 82.9-85.3% from brown rice. The relative standard deviation (RSD) was less than 15%. The limits of detection (LODs) of pymetrozine calculated as a sample concentration were 0.0003 mg kg⁻¹ (mg L⁻¹) for soil and paddy water, 0.001 mg kg⁻¹ for brown rice and rice straw. The results of kinetics study of pymetrozine residue showed that pymetrozine degradation in water, soil, and rice straw coincided with C = 0.194e^−0.986t, C = 0.044e^−0.099t, and C = 0.988e^−0.780t, respectively; the half-lives were about 0.70 d, 7.0 d and 0.89 d, respectively. The degradation rate of pymetrozine in water was the fastest, followed by rice straw. The highest final pymetrozine residues in brown rice were 0.01 mg kg⁻¹, which was lower than the EU’s upper limit of 0.02 mg kg⁻¹ in rice. Therefore, a dosage of 300-600 g a.i.hm⁻² was recommended, which could be considered as safe to human beings and animals.     

Influence of fipronil compounds and rice-cultivation land-use intensity on macroinvertebrate communities in streams of southwestern Louisiana, USA

Laboratory tests of fipronil and its degradation products have revealed acute lethal toxicity at very low concentrations (LC50) of <0.5 microg/L to selected aquatic macroinvertebrates. In streams draining basins with intensive rice cultivation in southwestern Louisiana, USA, concentrations of fipronil compounds were an order of magnitude larger than the LC50. The abundance (rho=-0.64; p=0.015) and taxa richness (r2=0.515, p<0.005) of macroinvertebrate communities declined significantly with increases in concentrations of fipronil compounds and rice-cultivation land-use intensity. Macroinvertebrate community tolerance scores increased linearly (r2=0.442, p<0.005) with increases in the percentage of rice cultivation in the basins, indicating increasingly degraded stream conditions. Similarly, macroinvertebrate community-tolerance scores increased rapidly as fipronil concentrations approached about 1 microg/L. Pesticide toxicity index determinations indicated that aquatic macroinvertebrates respond to a gradient of fipronil compounds in water although stream size and habitat cannot be ruled out as contributing influences.     

锐颈特与马拉硫磷交替使用对麦穗鱼脑乙酰胆碱酯酶活性恢复的 …

研究了５％锐颈特县浮剂与９５％马拉硫磷文替使用对麦穗鱼（Ｐｓｅｕｄｏｒａｓｂｏｒａ ｐａｒｏａ）乙酰胆碱酯酶（ＡＣｈＥ,ＥＣ３．１．１．７）活性的影响。结果表明,０．２ｍｇ／Ｌ,锐颈物与２ｍｇ／Ｌ马拉硫磷交替使用均影响被抑制的ＡＣｈＥ活性恢复。文中还探讨了研究农药影响对于合理评价农药环境毒性的意义。     

Fate and distribution of fipronil on companion animals and in their indoor residences following spot-on flea treatments

Use of fipronil {5-amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-trifluoromethyl)sulfinyl]-1H-pyrazole-3-carbonitrile CAS 120068–37-3} topical pet products on dogs and cats introduces low level residues into residences. Distribution and fate studies of fipronil on pets and in residences were performed to evaluate potential determinants of human exposure. Fipronil, desulfinyl fipronil, fipronil sulfone and fipronil sulfide were measured on hair clippings and brushed hair. The derivatives usually represented <10% of fipronil applied. Cotton gloves worn over impervious nitrile gloves, cotton cloths placed indoors in locations frequented by pets, and cotton socks worn by residents as direct dosimeters collected fipronil and its derivatives listed above in low amounts during 4-week study periods. Subsequent acid hydrolysis urine biomonitoring did not reveal significant excretion of biomarkers at ppb levels. The human exposure potential of fipronil is low relative to levels of health concern.     

Effect of fipronil on biogas production performance during anaerobic digestion of chicken manure and corn straw

Fipronil is a broad-spectrum insecticide that has a good control effect on pests of commercial poultry. Although many studies have reported the environmental fate of fipronil, the influence of residual fipronil in poultry waste on biogas production has not been further explored yet. In this article, an experimental comparative study on anaerobic digestion (AD) of chicken manure (CM) and corn straw (CS) with different fipronil concentrations (FCs) was carried at 8% of total solid (TS) and mid-temperature (35?±?1)°C. The results showed that fipronil had a significant effect on biogas production during AD of CM and CS. When the FC is at a low level (≤10?mg·kg^?1), the biogas production rate is increased and the digestion period was shortened, while higher FC (≥ 20?mg·kg^?1) showed an inhibitory effect. During the monitoring of enzyme activity, low FC showed no significant effect on cellulase and saccharase, but the urease activity increased in the early stage. High FC showed inhibition of activity of cellulase and urease, but the saccharase activity was significantly inhibited until FC reached 40?mg·kg^?1. This study also confirms that the environment in anaerobic digester is favorable for the degradation of fipronil, and its half-life is about 15.83?days.     

Assessing supercritical fluid extraction for the analysis of fipronil,kresoxim-methyl,acrinathrin, and pyridaben residues in melon

An analytical method, using supercritical fluid extraction (SFE), was assessed for residue analysis of the insecticides fipronil, acrinathrin and pyridaben and the fungicide kresoxim-methyl in melons. Extraction conditions were optimized on glass beads, as inert material, evaluating different pressures, temperatures, and CO₂ volumes. Also, the extractability of pesticides from hydromatrix and anhydrous magnesium sulfate was evaluated. Both adsorbents were evaluated for the preparation of SFE-spiked melon samples. Extractions of fortified samples were done using 20 mL of CO₂, 300 atm, and 50°C. Different extraction conditions, including the addition of water and methanol as a static modifier, were used to assess the extractability of these pesticides, and the addition of methanol was demonstrated to improve the extraction of all the studied pesticides.     

Error propagation in pesticide residue measurements estimated by computational simulations and inter-laboratory sample analysis

An assessment of the error associated with conventional pesticide residue analysis has been conducted based on computer simulations and inter-laboratory residue analysis. Computational simulations were conducted based on (i) typical performance and regulatory acceptance criteria of analytical methods, and (ii) field residue distributions. In addition, field samples with incurred residues were sent to different private laboratories and the results compared. The relative difference in pesticide residues obtained when samples from the same field or produce lot are analyzed at separate laboratories was used to quantify the uncertainty associated with residue analyses performed using common analytical technology, and methods that are in compliance with current regulatory requirements. The study showed that differences of > 100% are common and should be expected when samples from the same crop are analyzed at different laboratories. The results also suggest that the error within residue measurements can be particularly detrimental when a result is reported near the maximum residue limit (MRL).     

A device for sampling the mud‐water interface in eutrophic lakes and bogs for residue analysis

Abstract

A tubular device has been developed making it possible to obtain layered samples of loosely aggregated, flocculent material from bogs or eutrophic lakes. The samples are up to 50 cm long and 15 cm in diameter. The sampler is free from protuberances and intact, layered samples can be taken. The tubular part of the sampler is about 85 em long, the walls of the lower 25‐cm portion harbouring a pneumatic closing mechanism which is controlled from above the water surface. An extendible handle for manipulating the sampler and for guiding it into place, is fastened to the upper end of the sampling tube. The performance and the operation of the sampler in the field are described.     

Disposition of fipronil in rats

In the scientific literature, little attention has been paid to the disposition of fipronil, a phenyl pyrazole insecticide. In this study, the tissue distribution, the metabolic fate, and the elimination of fipronil was investigated in rats using radiolabeled fipronil. When a single oral dose of ¹⁴C-fipronil (10 mg kg⁻¹ b.w.) was given to rats, the proportion of dose eliminated in urine and feces 72 h after dosing was ca 4% for each route. At the end of the experiment the highest levels of radioactivity were found in adipose tissue and adrenals.     

Electron donor capacity of reducing dissolved organic matter from crop residue decomposition as probed by chronoamperometry

Reducing dissolved organic matters (RDOMs) from the anaerobic decomposition of crop residue can greatly affect the physicochemical and biological properties of soils. Electrochemical methods that can effectively protect them from oxidation and rapidly obtain results, such as differential pulse voltammetry (DPV), have been applied to qualitatively analyzing properties of RDOMs. However, the donated amount of electrons from RDOMs as a capacity factor may be more crucial for evaluating their important roles. For the first time, matured chronoamperometry (CA) was applied to quantitatively determining the electron donor capacities of RDOMs in crop residue management. The electron donor capacities of RDOMs from green manure were much higher than those from rice straw, which indicated that the former had greater effect on the redox status and reactions of soil. Chronoamperometry was proposed as a practical and effective method to quantitatively characterize RDOMs from residue decomposition.     

Dynamics of PAH deposition, cycling and storage in a mixed-deciduous (Quercus-Fraxinus) woodland ecosystem

Estimates of standing biomass and fluxes of biomass in a mixed-deciduous woodland were derived, and used with results for concentrations of seven polycyclic aromatic hydrocarbons (PAHs) in different compartments of the woodland system to quantitatively assess some of the key fluxes and burdens of PAHs in this complex system. We quantified PAH burdens in air, in leaves of three deciduous tree species, in leaf litter and in soil, and uptake of PAHs by the tree leaves; PAH fluxes in litterfall, and deposition to the litter layer on the woodland floor during winter were calculated from these data. Air burdens exhibited marked seasonal variations for all compounds, with lowest values in summer when combustion-related emissions were low. Leaves did not accumulate large burdens of PAHs while on the trees and consequently, litterfall-associated fluxes of PAHs were small, representing only a fraction of the burdens in the litter layer to which they were deposited. Higher PAH burdens in air in winter, combined with the organic-matter-rich nature of the litter layer, are thought to be responsible for fluxes of PAHs to the litter layer in winter being 20-170 times the peak litterfall fluxes. The soil compartment was calculated to contain 25 years' worth of deposition of benzo[ghi]perylene, the most recalcitrant PAH in this study. Storage quotients for fluoranthene, pyrene, benzo[k]fluoranthene and benzo[a]pyrene burdens in soil represented 7-10 years' worth of deposition, while fluorene and phenanthrene storage in soil approached unity with inputs (1 and 3 years' worth of deposition, respectively). The relative importance of storage and loss processes was therefore closely related to the physico-chemical properties of the PAH, and is discussed in relation to the cycling of carbon in the woodland.     

蔬菜中有机磷农药残留研究及对策

以西安市为例，研究了蔬菜中有机磷农药的残留问题，分析了不同农药在蔬菜中的残留特征以及不同品种蔬菜、不同类型蔬菜中农药残留的特征，讨论了蔬菜中农药残留量超标的原因及相关对策。     

Occurrence of Fipronil in residential house dust in the presence and absence of pets: a hint for a comprehensive toxicological assessment

The presence of the insecticide Fipronil and its main products of toxicological relevance, namely Sulfone and Desulfinyl, was assessed in 161 residential house dust samples in the absence (N?=?101) and presence (N?=?60) of cats and dogs in Italy. High-resolution mass spectrometry analysis revealed a significant difference (p?<?0.001) in the dust contamination in the presence of pets (median: 467 vs. 24?ng/g dry weight), even if the highest value was found in the absence of pets (82,069 vs. 67,799?ng/g dry weight). Fipronil intake estimates from dust in toddlers, computed according to US-EPA and EU-ECHA guidelines, ranged from 333 to 556 and from 20 to 34?ng/kg per day for acute and chronic scenario, respectively. Dust seemed not able itself to lead to Fipronil overexposure with respect to acute and chronic toxicity health-based guidance values. Kittens were potentially overexposed to Fipronil under both acute (26,076?ng/kg per day) and chronic (1,633?ng/kg per day) scenarios. The mild symptomatology associated with acute intoxication could possibly determine case underreporting within pharmacosurveillance schemes. Its administration was estimated in 7.3–9.7 tons per year. Such a range suggests its prudent use under strict veterinary control to prevent pest resistance and ecotoxicological outcomes.     

The mobility of thiobencarb and fipronil in two flooded rice-growing soils

The mobility of the rice pesticides thiobencarb (S-[(4-chlorophenyl) methyl] diethylcarbamothioate) and fipronil ([5-amino-3-cyano-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-[(trifluoromethyl)sulfinyl]pyrazole) were investigated in the glasshouse under flooded conditions using two Australian rice-growing soils. When using leakage rates of 10 mm day^?1, less than 20% of applied thiobencarb and fipronil remained in the water column after 10 days due to rapid transfer to the soil phase. Up to 70% and 65% of the applied thiobencarb and fipronil, respectively, were recovered from the 0–1 cm layer of soils. Only 5–7% of each pesticide was recovered from the 1–2 cm layer, and less than 2% was recovered from each 1 cm layer in the 2–10 cm region of the soils. Analysis of the water leaking from the base of the soil cores showed between 5–10% of the applied thiobencarb and between 10–20% of the applied fipronil leaching from the soil cores. The high levels of pesticide in the effluent was attributed to preferential flow of pesticide-laden water via soil macropores resulting from the wetting and drying process, worm holes and root channels.     

The mobility of thiobencarb and fipronil in two flooded rice-growing soils

The mobility of the rice pesticides thiobencarb (S-[(4-chlorophenyl) methyl] diethylcarbamothioate) and fipronil ([5-amino-3-cyano-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-[(trifluoromethyl)sulfinyl]pyrazole) were investigated in the glasshouse under flooded conditions using two Australian rice-growing soils. When using leakage rates of 10 mm day(-1), less than 20% of applied thiobencarb and fipronil remained in the water column after 10 days due to rapid transfer to the soil phase. Up to 70% and 65% of the applied thiobencarb and fipronil, respectively, were recovered from the 0-1 cm layer of soils. Only 5-7% of each pesticide was recovered from the 1-2 cm layer, and less than 2% was recovered from each 1 cm layer in the 2-10 cm region of the soils. Analysis of the water leaking from the base of the soil cores showed between 5-10% of the applied thiobencarb and between 10-20% of the applied fipronil leaching from the soil cores. The high levels of pesticide in the effluent was attributed to preferential flow of pesticide-laden water via soil macropores resulting from the wetting and drying process, worm holes and root channels.     

Photolysis of spinosyns in seawater, stream water and various aqueous solutions

Spinosad, a reduced-risk insecticide, contains primarily two active compounds, spinosyns A and D that are fermentation products of bacterium Saccharopolyspora spinosa. It is currently used to control fruit flies in Hawaii, USA. In this study, we investigated photodegradation of spinosyns A and D, respectively, in seawater, stream, tap and distilled-deionized waters under various light sources. Photodegradation of the two chemicals was also studied in various aqueous solutions prepared with phosphate buffer at different pH or chemical sensitizers. Two major photolytic products from spinosyn A were detected as spinosyn B and hydroxylated spinosyn A. Spinosyn D was similarly hydroxylated and N-demethylated. Spinosyns A and D were photodegraded rapidly under sunlight in Hawaii, USA. The half-life of spinosyns A and D in stream water was 1.1 and 1.0 h, respectively, and was a half of that in distilled-deionized water, 2.2 and 2.0 h, respectively. Photodegradation of spinosyns A and D followed an order of increasing rate constants in distilled-deionized, seawater, stream and tap water under 300 nm artificial light, and was enhanced approximately 8- and 17-fold, respectively, in acetone-sensitized solution as compared to in distilled-deionized water. Photolysis rates of spinosyns A and D in isopropanol- or humic acid-fortified water did not differ much as compared with those accordingly in distilled-deionized water. Spinosyns A and D photodegraded slower in acidic aqueous solution than in basic aqueous solution.     

Effects of pyridaphenthion on growth of five freshwater species of phytoplankton. A laboratory study

The acute toxicity of the insecticide and acaricide pyridaphenthion to five species of freshwater phytoplankton, Scenedesmus acutus, Scenedesmus subspicatus, Chlorella vulgaris, Chlorella saccharophila and Pseudanabaena galeata was determined. Insecticide concentrations eliciting a 50% growth reduction over 96 h (EC₅₀) ranged from 2.2 to 30.9 mg/l. The two species of Chlorella and the cyanobacteria P. galeata were more tolerant than the two species of Scenedesmus. Concentrations of pyridaphenthion detected in some natural waters were less than the toxic threshold for these species.     

The degradation of parathion and DDT in aqueous systems containing organic additives

Abstract

Laboratory studies were conducted to investigate some of the factors influencing pesticide degradation in‐ aqueous systems. Parathion added to natural water in ethanol, acetone or without organic solvent, was completely degraded within 2 wk. While most of the parathion was reduced to amino‐parathion when added in ethanol, no amino‐parathion was detected in the presence of acetone or when no solvent was added, suggesting that in the latter two cases the insecticide was aerobically degraded to other metabolites. No paraoxon was detected. When ethanol concentration was increased from 1% to 2 and 4%, the rate of parathion degradation was inversely related to the ethanol concentration. In the presence of glucose as a carbon source, approximately 50% of the parathion was reduced to aminoparathion. DDT degradation in natural water was more rapid when it was added in ethanol than when added in acetone. The only DDT metabolite detected was TDE, with about 36% conversion in presence of ethanol, and 20% when the DDT was added in acetone.     

焦化废水中细菌质粒的研究

细菌质粒中常带有一些可编码降解特殊有毒物质酶的基因,为了研究质粒对有毒物质CN^-的降解的意义,主要调查了焦化废水中好氧异养菌的质粒分布特点。从山西省焦化企业公司生化站、太原煤气公司焦化厂生化站中筛选出53株细菌,利用琼脂糖凝胶电泳法,采用GDS-8000型凝胶电泳分析仪进行拍照,同时测定各菌株降氰、降酚能力,CN^-采用异烟酸-毗唑啉酮法,酚采用4-氨基安替比林法测定。结果表明,质粒的存在与降氰力有一定的关系,但对降酚力的影响差异不显著。同时,通过对其中11^*号菌株进行了质粒转化和消除实验,证明质粒稳定,不可用十二烷基磺酸钠(SDS)消除掉,用E．cbli DHI作受体菌,用11^#菌株作供体菌。作转化实验,但由于种种原因,没有筛洗到转化子。