Insecticide toxicity to Hyalella curvispina in runoff and stream water within a soybean farm (Buenos Aires, Argentina)

Toxicity to the locally dominant amphipod Hyalella curvispina was assessed in a first-order stream running through a cultivated farm. Cypermethrin, chlorpyrifos, endosulfan and glyphosate were sprayed throughout the studied period. Toxicity was assayed under controlled laboratory conditions with runoff and stream water samples taken from the field under steady state and flood conditions. Ephemeral toxicity pulses were observed as a consequence of farm pesticide applications. After pesticide application, runoff water showed 100% mortality to H. curvispina for 1 month, but no mortality thereafter. Toxicity persistence was shortest in stream water, intermediate in stream sediments and longest in soil samples. Runoff had a more important toxicity effect than the exposure to direct aerial fumigation. The regional environmental features determining fast toxicity dissipation are discussed.     

Analysis of pyrethroids in sediment pore water by solid-phase microextraction

Sediment toxicity from trace contamination of pyrethroid insecticides is an emerging water quality concern. Pyrethroids are highly hydrophobic, and their sediment toxicity is related to the freely dissolved concentration in pore water. Solid-phase microextraction (SPME) was evaluated as a selective method to analyze free concentrations of eight pyrethroids in sediment pore water, and SPME measurements were compared to total pore-water concentrations measured using a conventional liquid-liquid extraction (LLE) method. Free pore-water concentrations detected by SPME (C(w-SPME)) were 4.1 to 37% of the total concentration given by LLE (C(w-LLE)) in pore water prepared from a freshwater sediment and only 3.2 to 13.3% in the pore water of a marine sediment. The difference suggested predominant partitioning of pyrethroids into the dissolved organic matter phase in pore water. The method detection limits of the SPME method were lower than the 10th percentile of the reported median lethal concentrations for aquatic organisms, with relative standard deviation <20% as determined over 200 analyses. The SPME method was further used to analyze field-contaminated sediment samples. Those analyses showed that the phase distribution of pyrethroids in sediment was influenced by sediment type and other conditions. Our results show that SPME provides a sensitive, reproducible, and practical method for screening sediment toxicity from potential pyrethroid contamination.     

Measuring pyrethroids in sediment pore water using matrix-solid phase microextraction

Pyrethroids are hydrophobic insecticides commonly used in both agricultural and urban environments. Their high toxicity to aquatic organisms, including benthic invertebrates, and detection in the sediment at many locations in California, U.S.A., have spawned interest in understanding their bioavailability in bed sediments. A recent study showed good correlation between uptake of 14C-permethrin in Chironomus tentans and solid-phase microextraction (SPME) fibers in sediments. The present study was directed at the development of an SPME technique applicable to trace levels of nonlabeled pyrethroids in sediment. Disposable polydimethylsiloxane fibers were used to detect freely dissolved pore-water concentrations of bifenthrin, fenpropathrin, cis-permethrin, trans-permethrin, cyfluthrin, cypermethrin, and esfenvalerate under agitated and static conditions. Partition equilibrium between fiber and sediment was reached in <5 d when the samples were agitated on a shaker at low speed, while much longer times (>23 d) were needed without agitation. Polydimethylsiloxane to water partition ratios (K(PDMS)) of the seven pyrethroids were measured separately and ranged from 2.83 x 10(5) to 1.89 x 10(6). When applied to field-contaminated sediments, agitated matrix-SPME was able to detect pore-water concentrations as low as 0.1 ng/L. The method developed in the present study may be coupled with bioassays to gain mechanistic understanding of factors affecting pyrethroid toxicities, and applied to field samples to better predict sediment toxicities from pyrethroid contamination.     

气相色谱法测定水中三氯杀螨醇和除拟虫菊酯的方法验证

目的验证气相色谱法测定水中三氯杀螨醇和7种除拟虫菊酯。方法水样中的微量三氯杀螨醇和除拟虫菊酯经液液萃取后,利用HP-5毛细管柱,在程序升温条件下进行GC分析,以保留时间定性,外标法定量。结果质量浓度0.156~5.00μg/mL范围内线性关系良好,相关系数r0.996 0,回收率范围为81.9%~106.7%,RSD为0.5%~4.8%。采用本法对10件水样进行检测,均未检出三氯杀螨醇和7种除拟虫菊酯。结论气相色谱法操作简便,测定结果可靠,方法稳定性和重复性较好,可以满足生活饮用水中三氯杀螨醇和7种除拟虫菊酯测定要求。     

Effects of apple orchard runoff on the aquatic macrofauna of a mountain stream

As part of a statewide evaluation of the impact of nonpoint sources of water pollution (relevant to Section 208 of the Federal Water Pollution Control Act Amendments of 1972), a study was conducted to determine the effects of surface runoff from apple orchards. It was conducted by the Biological Monitoring Group of the North Carolina Division of Environmental Management using aquatic macroinvertebrates as assessment organisms. Both taxa richness and total numbers were reduced below the orchards, particularly during two pesticide application periods. Results indicate chronically severe stress conditions at the most downstream site and periodic stress, followed by recovery, at an upstream site. Several taxa were especially susceptible to apple orchard runoff, includingEpeorus (Iron) sp. and all Plecoptera.     

Comparison of the synthetic pyrethroids Esbiothrin and Bioresmethrin with Scourge and Cythion against adult mosquitoes in a laboratory wind tunnel.

Both candidate adulticides, Esbiothrin and Bioresmethrin, exhibited quick knockdown 1-h posttreatment. Esbiothrin elicited the fastest knockdown, but Bioresmethrin was more effective at both 1- and 24-h posttreatment than either Esbiothrin or Scourge against both Aedes taeniorhynchus and Culex quinquefasciatus. Mosquitoes treated with Scourge required more time and a higher dosage to respond in a physiological manner similar to those treated with either of the candidate adulticides. More than twice the dosage rate of Cythion was required than either candidate adulticide to cause a similar physiological response in treated mosquitoes.     

Terrestrial non-target invertebrates and the autumn application of synthetic pyrethroids: Experimental methodology and the trade-off between replication and plot size

The effects of the synthetic pyrethroid, deltamethrin ((S)-a-cyano-3-phenoxybenzyl (1R)-cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylate) on the non-target invertebrate fauna of winter-wheat was monitored over two cropping cycles. The product was applied at decimal growth stage 12–13 in the first week of November in 1986 and 1987. In 1986, demeton-S-methyl (S-2-ethylthioethyl O,O-dimethyl phosphorothioate) was applied as a toxic standard. Short-term depletions were detected in the autumn-active, field-overwintering Carabidae, especially Bembidion obtusum, Nebria brevicollis and Pterostichus melanarius. Staphylinidae were largely unaffected during the winter months however, significant increases in summer-active species were detected in both years. The most profound effects were on the Linyphiidae with 168–221 day depletions in the 4 ha plots in 1986/7 and 89–145 day reductions in the 1 ha plots used in 1987/8. Meioneta rurestris was the most affected species. In general, pyrethroid effects were greater than organophosphate effects, especially in the case of spiders. Summer aphid infestations tended to be lower in the pyrethroid-treated plots, possibly as a result of overwintering aphid control. No evidence for sub-lethal effects (number of eggs per female and proportion with empty crops) were found in the carabid, Trechus quadristriatus however, the proportion of female beetles was higher in the pyrethroid-treated plots. B. obtusum and P. melanarius numbers were significantly reduced within small, barriered areas 160 days after treatment within the pyrethroid-treated plots in 1987/8. This suggests that recolonisation of treated areas may reduce or dilute the duration of effects that would be detected in the whole-field treatments characteristic of the real world. Support for this was also obtained from the direct relationship between the duration of effects and plot size in the two years of the study. The potential for using models incorporating spatial dynamics to assist interpretation of experimental results is discussed.     

Health effects of pyrethrins and pyrethroids

Pyrethrins, natural extracts of Chrysanthemum cinerariaefolium and Chrysanthemum cocineum flowers, and pyrethroids, synthetic analogues and derivatives of pyrethrins, are powerful insecticides. They are widely used in households and insect control in pets or livestock, in textiles such as carpets, wallpapers, furniture and clothes, as well as in agriculture, forestry and public health services. This article brings a list of pyrethrin and pyrethroid insecticides registered for use in plant protection in Croatia. Pyrethrins and pyrethroids can enter the organism by ingestion (accidental or suicidal ingestion or in food), by inhalation and/or by skin contact. Although these pesticides pose a relatively low risk to mammals due to rapid metabolism with no significant accumulation, they can induce adverse health effects, more often in acute poisoning, but also due to chronic exposure. The primary target of pyrethrin and pyrethroid toxicity is the nervous system, since they act directly on the sodium channels of nerve cell axons, leading to hyperexcitation. Another important toxicological mechanism is allergenicity, which is more pronounced with pyrethrins than with synthetic pyrethroids. Because there is no antidote for pyrethrin and pyrethroid poisoning, treatment is symptomatic and supportive. The article discusses the measures for poisoning prevention and alleviation of exposure to pyrethrins and pyrethroids in occupational settings and in general population.     

Insecticidal activity of synthetic pyrethroids, organophosphates, insect growth regulators, and other livestock parasiticides: an Australian perspective

The present review is restricted to the collation and evaluation of information describing the excretion profile and ecotoxicity of veterinary medicines developed specifically for the control of either internal or external parasites of livestock. It identifies numerous gaps in our knowledge and highlights our poor understanding of the environmental fate of many of these chemicals, especially those developed for the control of ticks, lice, and/or biting flies. Residues of most anthelmintics are largely harmless to dung-feeding arthropods, but those of many ectoparasiticides, especially the synthetic pyrethroids, are highly toxic to fly larvae and adult dung beetles. Organophosphates, because they are metabolized extensively and eliminated mostly in urine, are considered to be unlikely to have a major impact on the development or survival of dung-dwelling organisms. The present review stresses the need for better information regarding spatial and temporal usage patterns of veterinary parasiticides, and it examines the role of ecotoxicological models for evaluating their impact on populations of dung-dependent arthropods.     

Acute and chronic effects of particle-associated fenvalerate on stream macroinvertebrates: a runoff simulation study using outdoor microcosms

Agricultural edge-of-field runoff usually contaminates surface waters with particle-associated pesticides. However, the acute and chronic effects on the aquatic macroinvertebrate communities have rarely been addressed. Outdoor flow-through stream microcosms were exposed for 1 h in triplicate to approximately 3.1 g/L of total suspended solids spiked with 0.0, 13.6, 136, or 1,365 μg/kg of the pyrethroid insecticide fenvalerate (FV). The effects on eight species typical of agricultural streams were monitored for 93 days. Gammarus pulex (Amphipoda) and Hydropsyche angustipennis (Trichoptera) showed a sensitive acute drift reaction with increased drift levels in all FV treatments (p < 0.05). The caddisfly species Anabolia nervosa, Plectrocnemia conspersa, and Limnephilus lunatus as well as the dipteran species Tipula maxima were less sensitive, with a significant increase in drift in the 136- and 1,365-μg/kg treatments. Temporal pattern of emergence was significantly altered in the 1,365-μg/kg treatment for A. nervosa (p < 0.05). The most sensitive species in terms of total emergence or survival were L. lunatus, which showed a significant effect in the 136- and 1,365-μg/kg treatment, as well as adult and juvenile G. pulex and T. maxima, with a significant effect level in the 1,365-μg/kg treatment (p < 0.05). Total emergence or survival of A. nervosa, P. conspersa, and H. angustipennis decreased with increasing exposure level, but differences from the control were not significant. Neither acute drift nor chronic mortality was observed for Helodes minuta (Coleoptera) and Radix peregra (Gastropoda). This study highlights the ecotoxicological importance and bioavailability of field-relevant levels of particle-associated hydrophobic chemicals transiently introduced into surface waters during runoff events. Received: 26 June 2000/Accepted: 20 November 2000     

Detection of human enteric viruses in stream water with RT-PCR and cell culture

A multiplex RT-PCR method was used to measure virus occurrence at five stream water sites that span a range of hydroclimatic, water-quality, and land-use characteristics. The performance of the molecular method was evaluated in comparison with traditional cell culture and Escherichia coli membrane filtration assays. The study incorporated multiple quality controls and included a control for virus recovery during the sampling procedure as well as controls to detect potentially false-negative and false-positive data. Poliovirus recovery ranged from 16 to 65% and was variable, even in samples collected within the same stream. All five sites were positive for viruses by both molecular and cell culture-based virus assays. Enteroviruses, reoviruses, rotaviruses, and hepatitis A viruses were detected, but the use of the quality controls proved critical for interpretation of the molecular data. All sites showed evidence of faecal contamination, and culturable viruses were detected in four samples that would have met the US Environmental Protection Agency's recommended E. coli guideline for safe recreational water.