Procedure for the determination of 2,4‐D and dicamba in inhalation,dermal, hand‐wash,and urine samples from spray applicators

Abstract

Analytical procedures for the simultaneous determination of residues of 2,4‐D and dicamba from polyurethane foam plug air samplers, ethylene glycol impregnated glass‐fiber filter paper dermal samplers, 1% sodium bicarbonate hand wash solution, and urine are presented. Residues were derivatized with diazomethane and quantitated using electron capture gas chromatography. Recoveries were greater than 80% at the limit of detection in all substrates. The limits of detection for both herbicides were 0.1 μg/foam plug and 0.5 μg/filter paper, and in the urine, 1.7 μg/100 mL and 5.0 μg/100 mL for dicamba and 2,4‐D, respectively.     

Teratogenicity of bifenox and nitrofen in rodents

Abstract

The teratogenicity of the diphenyl ether herbicide bifenox [2,4‐dichlorophenyl 3'‐carboxymethyl‐4'‐nitrophenyl ether] was compared to that of nitrofen [2,4‐dichlorophenyl 4'‐nitrophenyl ether] in rats and in mice. Neither compound increased prenatal mortality in mice. Because nitrofen causes both malformations that are compatible with survival to weaning and a high incidence of perinatal (but not of fetal) mortality, emphasis was placed on postnatal parameters of bifenox toxicity. In rats, bifenox caused a low incidence of “bloody tears”;, but it did not decrease survival to term or to weaning in rats or mice, and did not reduce Harderian gland weight in mice. Because the weight of the Harderian glands is a more objective measure of their status than is the presence of an eye discharge, it is concluded that bifenox is not teratogenic at the levels administered. Nitrofen decreased litter size, pup weight, and Harderian gland weight in mice.     

磺酰脲类除草剂在环境中的光降解研究——水溶液中的光解动力学

以汞灯为光源,研究了甲黄隆,苯黄隆,氯黄隆,氯嘧黄隆,苄嘧黄和胺苯黄隆６种磺酰脲类除草剂在水液中的光解动力淡。结果表明,５种磺酰的降解呈一级动力学反应;体系的ＰＨ值对降解速率影响不明显,光强的影响较明显著;Ｈ２Ｏ２丙酮和溶解有机质均可促进磺酰光解;党妥氧对该类除草剂光解的影响表现为光氧化与淬灭２种作用的竞争。     

紫茎泽兰的化学防除及生态修复效果

紫茎泽兰是我国重要的外来入侵生物,一旦入侵,就排挤当地物种,很快成为优势种群,在西南地区已对当地的农业、畜牧业,以及生态环境造成严重的破坏.2年的试验和示范结果表明,磺酰脲类除草剂嘧磺隆187.5～375g/hm2(有效成分,下同)、噻吩磺隆375g/hm2、氯嘧磺隆375g/hm2和吡啶类除草剂氨氯吡啶酸1 080g/hm2对紫茎泽兰均有优异的防除效果.而2,4-滴1 500g/hm2、乙羧氟草醚150g/hm2、氟磺胺草醚500g/hm2、咪唑乙烟酸1 500g/hm2、嗪草酸甲酯50g/hm2、环嗪酮2 500g/hm2、氯草定750～1 500g/hm2不能完全杀死紫茎泽兰.针对山区水源短缺,运水不便的的问题,通过在除草剂中加入2 L/hm2机油乳油,采用很低容量喷雾法,用水量可由常量喷雾的900～1 200L/hm2减少到30～40L/hm2,施药效率较常量喷雾提高8～10倍.此外,还可将除草剂制成颗粒剂或采用毒土法撒施,不需施药器械,且可以节省大量水运输费用.紫茎泽兰用上述除草剂防除后,能选择性地促进非靶标植物的生长.大面积防除2年后,生态恢复率为40%～90%.     

Responses of different fungal and plant species to acetolactate synthase inhibitors and their derivatives

Abstract

The effect of sulfonylurea (SU) acetolactate synthases (ALS) inhibitors (chlorsulfuron and triasulfuron) and their 13 guanidine and 7 azole derivatives was studied on 17 fungal and 21 plant species. The efficacy of chlorsulfuron and triasulfuron against Fusarium oxysporum and Thielaviopsis basicola was higher than carbendazim. Two azole derivatives were highly selective for maize. The antifungal activity spectrum of both guanidine and azole derivatives differed from that of chlorsulfuron and triasulfuron, and did not exert notable antifungal activity in vitro. However, they had significant anti‐Fusarium efficacy on rye that surpassed that of carbendazim.     

2种低温等离子体降解土壤中乙草胺和阿特拉津

研究了沿面放电和平板介质阻挡放电处理土壤中阿特拉津和乙草胺的效果。主要以沙子作为研究体系,考察了水分、氧气流速、活性炭和过硫酸钠对降解的影响。结果表明:沿面放电装置和平板介质阻挡放电都能高效降解沙子中的乙草胺、阿特拉津;水分和氧气流速对降解的影响较大,在一定限度内,它们的增加能迅速提高降解效果,但过多的水分反而会抑制污染物的降解。活性炭显著抑制沿面放电降解乙草胺和阿特拉津效果,过硫酸钠与沿面放电、平板介质阻挡放电联用方法没有表现出协同效应。     

固相萃取-高效液相色谱法测定水中磺酰脲类除草剂

建立了固相萃取-高效液相色谱测定水中7种磺酰脲类除草剂的方法,考察了降解作用及滤膜对测定的影响.方法在0.30 mg/L～5.00 mg/L之间线性关系良好,7种磺酰脲类除草剂的检出限为0.32 μg/L～0.62 μg/L,RSD为4.4%～7.6%,平均加标回收率为87.9%～102%.     

Ability of Poplar (Populus spp.) to Detoxify Chloroacetanilide Herbicides

The ability of poplar trees to resist chemical stress caused by chloroacetanilide herbicides was studied. Detached leaves of Lombardy poplar (Populus nigra L.) were exposed to seven chloroacetanilide herbicides via uptake through the cut petiole. The leaves showed high tolerance against the phytotoxicity of these compounds. Their tolerance was further enhanced by treatment with 2-oxothiazolidine-4-carboxylic acid (OTC, a precursor of the amino acid cysteine). High levels of glutathione (GSH) and GSH S-transferase (GST) activity were detected in poplar leaves. Treatments with chloroacetanilide herbicides left the GSH content in the leaves unchanged but strongly induced the GST activity. In contrast, in OTC-treated leaves increased GSH contents were measured, but GST activities remained unchanged. It therefore appears that a highly active and inducible GSH-conjugation Phase II detoxification system in their leaves may make poplar trees useful for phytoremediation of soils contaminated with chloroacetanilide herbicides. Based on these findings a phytoremediation project using different poplar hybrids at a site heavily polluted with such compounds in Hungary has been launched.     

THE EFFECTS OF DIPOTASSIUM ENDOTHALL ON THE ZOOPLANKTON AND WATER QUALITY OF A SMALL POND1

ABSTRACT: Zooplankton samples and dissolved oxygen-temperature readings and water samples were taken from a treatment and control pond on 41 and 42 separate occasions, respectively, both before and after the application of 5.0 mg/l (a.i.) dipotassium endothall to the 0.31 ha treatment pond on May 31, 1973. Seasonal fluctuations in the density of Cladocera and Copepoda coincided quite closely in both ponds and were similar to the fluctuations reported in the literature to be typical of temperate region ponds and lakes. An apparent seasonal shift in generic composition from .Daphnia spp. in May to Ceriodaphnia spp. in June to Chydorus spp. from July/early September occurred in both ponds and is thought to be at least partially due to fish predation. No apparent changes in species composition or generic densities of Cladocerans was noted in the treatment pond that did not also occur in the control pond. There were no noticeable effects of the dipotassium endothall on either the Calanoida or Cyclopoida suborders of Copepoda. A later pulse of Ostracoda in the treatment pond, when compared to the control, may have been due to the dipotassium endothall or to a combination of the effects of the herbicide on the macrophytes and the method of sampling. A decrease in dissolved oxygen below saturation, occurring in the treated pond from 3–21 days after treatment, was attributed to an increase in biological oxygen demand associated with weed-kill. There was no noticeable increase in plant nutrients (N and P) in the treated pond following herbicide application, nor were there any apparent changes in the other chemical parameters studied.     

EFFECTS OF FOREST HERBICIDE APPLICATIONS ON STREAMWATER CHEMISTRY IN SOUTHWESTERN BRITISH COLUMBIA1

ABSTRACT: The herbicide glyphosate was applied to portions of two watersheds in southwestern British Columbia to kill vegetation that was competing with Pseudotsuga menziesii (Douglas-fir) plantations. This application had little significant effect on streamwater chemistry (K⁺, Na²⁺, Mg²⁺, Ca²⁺, Cl^-, NOs₃^-, NH₄⁺, PO4^3-, SO₄⁼, and SiO₂ concentrations, electrical conductivity, and pH) when vegetation cover in a watershed was reduced by 4%, but had significant (P>0.05) effects, which lasted for at least five years, when cover was reduced by 43%. In this case, most parameters increased in value following the application, with K⁺ and Mg²⁺ concentrations and pH values exhibiting the most prolonged increases and NO₃^- concentrations exhibiting the greatest percentage increases. Sulphate and dissolved SiO₂ concentrations decreased following the application. Streamwater chemical fluxes showed similar trends to concentrations except that changes in fluxes were less significant and no decreases were observed. Forest management induced losses of NO₃-N in streamwater during the first five post-treatment years in the study area decreased in the order: herbicide application (approximately 40 kg/ha) < clearcutting and slashburning (approximately 20 kg/ha) < clearcutting (approximately 10 kg/ha). In watersheds similar to those of the study area, herbicide application is likely to have a greater impact on streamwater chemistry, in general, than would clearcutting or clearcutting followed by slashburning.