Decline of DDT residues in migratory songbirds

Analyses of ten species of migratory songbirds killed when the birds flew into television towers in Florida showed a progressive decline in the concentration of DDT and its metabolites (DDD and DDE) in their fat depots for the period 1964 to 1973. This decline is apparently correlated with the decreased usage of DDT in the United States during the same time.     

蔬菜不同部位对DDTs的富集与分配作用

在可控条件下研究了人为污染土壤中DDT类污染物在蔬菜(菠菜和胡萝卜)不同部位的富集与分配规律.结果表明,DDT类污染物在菠菜和胡萝卜叶部和根部均有一定富集,其中菠菜叶面富集量占富集总量的68.6%～92.2%之间;而胡萝卜叶部富集占富集总量的34.9%～41.6%之间.不同DDTs在菠菜和胡萝卜体内的生物富集量呈:P,p'-DDE>p,p'-DDT>p,P'-DDD>o,p'-DDE>o,P'-DDT的规律.DDTs通过不同途径在菠菜和胡萝卜内的生物富集系数表现如下规律:BCF大气-菠菜>BCF大气-胡萝卜>BCF土壤-胡萝卜>BCF土壤-菠菜.不同DDTs在蔬菜体内的生物富集系数表现为:BCFp,p-DDE>BCFo,p'-DDE>BCFp,p'-DDD>BCFp,p'-DDT>BCFo,p'-DDT.由于DDTs在蔬菜体内富集后,可沿食物链传递和放大,对农产品质量和人体健康构成直接威胁.     

DDT residues: distribution of concentrations in Emerita analoga (stimpson) along coastal California

The total concentrations (tDDT) of DDT [1,1,1-trichloro-2,2-bis(pchlorophenyl)ethane], DDD [1,1-dichloro-2,2-bis(p-chlorophenyl)ethanel, and DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] in Emerita analoga from 19 California beaches reflect tDDT contamination nearby. Animals near the Los Angeles County sewer outfall contain over 45 times as much tDDT as animals near major agricultural drainage areas. Sediments near the outfall probably contain over 100 metric tons of tDDT-a reservoir for input into marine organisms. The effluent from a plant that manufactures DDT is a probable source.     

Cope's rule, hypercarnivory, and extinction in North American canids

Over the past 50 million years, successive clades of large carnivorous mammals diversified and then declined to extinction. In most instances, the cause of the decline remains a puzzle. Here we argue that energetic constraints and pervasive selection for larger size (Cope's rule) in carnivores lead to dietary specialization (hypercarnivory) and increased vulnerability to extinction. In two major clades of extinct North American canids, the evolution of large size was associated with a dietary shift to hypercarnivory and a decline in species durations. Thus, selection for attributes that promoted individual success resulted in progressive evolutionary failure of their clades.     

Arctic seabirds transport marine-derived contaminants

Long-range atmospheric transport of pollutants is generally assumed to be the main vector for arctic contamination, because local pollution sources are rare. We show that arctic seabirds, which occupy high trophic levels in marine food webs, are the dominant vectors for the transport of marine-derived contaminants to coastal ponds. The sediments of ponds most affected by seabirds had 60 times higher DDT, 25 times higher mercury, and 10 times higher hexachlorobenzene concentrations than nearby control sites. Bird guano greatly stimulates biological productivity in these extreme environments but also serves as a major source of industrial and agricultural pollutants in these remote ecosystems.     

桂林海洋-寨底典型地下河系统地下水污染分析

选取海洋-寨底地下河系统为研究对象,采集8个水样进行水质全分析和挥发性有机物、半挥发性有机物测试。利用区域地下水污染调查评价技术要求中推荐的方法进行地下水质量评价、检出评价和超标评价,同时进行污染源和降解分析。分析结果表明,地下水水质总体尚好,Ⅲ类水占50%,Ⅳ类水主要超标指标为苯并(a)芘、总DDT;系统内的主要污染源为露天堆放的人畜粪便、农田施用的农药、化肥等,DDTs主要为历史积累的残留污染,HCHs则除了残留污染外,还可能有林丹的使用。     

Antagonism by DDT of the effect of valinomycin on a synthetic membrane

The potassium conductance which is induced by 10(-6) molar valinomycin in a lecithin-decane membrane is reversed by 3 x 10(-6) molar DDT. Membranes not treated with valinomycin are not affected by DDT. This blockade of potassium conductance parallels the effect of DDT on axonic conduction. Dieldrin and lindane, whose physiological actions are in some ways like those of DDT, do not affect valinomycin-induced conductance of lecithin-decane membranes.     

辽宁植烟土壤重金属含量和农药残留量调查与评价

为了解辽宁植烟土壤重金属污染和农药残留状况,对辽宁省10个植烟县(市)土壤的As、Hg、Pb、Cd、Cr、Cu和Ni 7种重金属含量及六六六(HCH)和滴滴涕(DDT)2种农药残留量进行了测定与污染评价。结果表明,无论辽宁植烟区整体还是各个县(市),土壤重金属Cr、Ni、Cu、As含量均达到国家土壤环境质量一级标准,Hg含量均达到国家土壤环境质量二级标准;Cd、Pb含量整体分别达到国家土壤环境质量二级、一级标准,仅个别地区处于一级、二级标准。无论辽宁植烟区整体还是各个县(市),土壤HCH和DDT残留量均达到国家土壤环境质量一级标准。土壤中As、Hg、Pb、Cd、Cr、Cu、Ni及HCH、DDT的污染指数均小于1,重金属的内梅罗综合污染指数为0.60,农药的内梅罗综合污染指数为0.042,两者均小于0.7。可见,辽宁植烟土壤处于清洁水平,适合无公害农产品生产。     

DDE residues and eggshell changes in Alaskan falcons and hawks

Eggshell thickness after exposure to DDT was reduced by 21.7 percent in Alaskan tundra peregrines, by 16.8 percent in taiga peregrines, by 7.5 percent in Aleutian peregrines, by 3.3 percent in rough-legged hawks, and not at all in gyrfalcons. Tundra peregrine eggs contain an average of 889 parts of DDE per million (lipid basis); taiga peregrine eggs contain 673 parts per million; Aleutian peregrine eggs contain 167 parts per million; rough-legged hawk eggs contain 22.5 parts per million; and gyrfalcon eggs contain 3.88 parts per million. These changes in eggshell thickness and the pesticide residues reflect different degrees of exposure to contamination. There is a highly significant negative correlation between shell thickness and DDE content in peregrine eggs. Tundra and taiga peregrines have fledged progressively fewer young each year since 1966.     

Airborne particulates in Pittsburgh: association with p, p -DDT

The DDT associated with samples of airborne particulates was measured by gas chromatography. Because of possible vaporization of DDT during sampling, concentrations reported represent minimum values but demonstrate that DDT can be present in an urban atmosphere that is distant from any large-scale agricultural activity.     

Anaerobic biodegradation of DDT to DDD in soil

DDT labeled with carbon-14 was added to soil, and the mixture was incubated anaerobically for 2 weeks and 4 weeks. DDT and seven possible decomposition products were separated by thin-layer chromatography, and the radioactivity of material from individual spots was determined by liquid scintillation. The DDT was dechlorinated by soil microorganisms to DDD, and only traces of other degradation products were detected. No degradation of DDT was detected in sterile soil.     

Binding of DDT to lecithin

An interaction between DDT and lecithin is indicated by the reciprocal effects of each compound on the proton magnetic resonance spectrum of the other. The phosphoryl choline moiety of the lecithin and the benzylic proton of the DDT seem to be involved. The most pronounced response in the proton magnetic resonance spectrum of the lecithin produced by increasing concentration s of DDT was a change in the chemical shift of the resonance peak due to the protons of the choline methyl groups. Increasing concentrations of lecithin produced changes in the chemical shift of the resonance peaks of the benzylic proton and adjacent ring protons of the DDT. Equilibrium constant of 0.597 +/-0.015 molal(-1) was obtained for this interaction.     

The site of action of DDT in the cockroach

(1) Although DDT undoubtedly affects motor nerves and muscle fibers in concentrations greater than 1,000 ppm, this action cannot be directly responsible for the clonic tremors in the DDT-poisoned cockroach which can be produced by internal concentrations of the order of 5 ppm. (2) DDT has no significant action on the cockroach central nervous system. (3) DDT emulsion perfused through the leg of the cockroach in concentrations as low as 0.01 ppm causes the appearance of a series of high frequency trains of axon spikes in the afferent fibers. (4) It is concluded that the tremors characteristic of DDT poisoning are due to an intense afferent bombardment of the motor neurons.     

DDT: interaction with nerve membrane conductance changes

The falling phase of action potentials of lobster giant axons is prolonged by DDT; finally a plateau phase is produced like cardiac action potentials. In axons poisoned with DDT, peak transient (sodium) currents associated with step depolarizations are turned off very slowly, and steady-state (potassium) currents are markedly suppressed. These two changes would cause the prolongation of action potentials and are considered the major ionic mechanisms of DDT action.     

Adenosine triphosphatase. Sensitive to DDT in synapses of rat brain

The insecticide DDT selectively inhibits the action of a Na(+), K(+), Mg(2+)-adenosine triphosphatase found in the nerve ending fraction of the rat brain. As judged by the concentrations of inhibitors that give 50 percent of enzyme inhibition, DDT was approximately 1000 times more toxic than its non-insecticidal analog, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene. The degrees of inhibition of this enzyme system by various toxic and nontoxic DDT analogs were closely related to a general toxicity in vivo of these compounds. Moreover, the extents of inhibition of this enzyme system by DDT were much higher at low temperatures, an indication of a causal relation between poisoning in vivo by DDT and the inhibition in vitro of the Na(+), K(+), Mg(2+)-adenosine triphosphatase system.     

过二硫酸钾在超声和紫外条件下氧化降解DDT的研究

[目的]研究过二硫酸钾氧化降解DDT反应的影响因素。[方法]考查pH值、氧化剂浓度、超声和紫外光对过二硫酸钾氧化降解DDT反应的影响,并应用于淡水和海水中。[结果]结果表明,随pH值的降低、过二硫酸钾浓度的升高,氧化降解DDT的效果越好。超声和紫外光的协同作用对反应的促进作用更大。应用于淡水和海水中氧化降解DDT,1.0 h DDT的降解率达90%,2.5 h DDT的降解率达99%。[结论]用过二硫酸钾氧化降解环境水中的DDT是一个适用范围较、效率高的简捷方法。     

我国农田土壤污染的环境成本分析

从粮食减产及质量下降的直接损失和生物多样性降低的间接损失2个方面,计量了我国农田土壤污染的环境成本。结果表明,1990~2005年我国粮食生产造成的农田土壤污染的环境成本约为208.54亿元/a,其中粮食减产及质量下降的直接损失为21.61亿元/a,农田生物多样性降低的间接损失为186.93亿元/a。     

THE SPECIFICITY OF THE XANTHYDROLPYRIDINE REACTION FOR 2, 2 BIS (p-CHLOROPHENYL) 1,1,1 TRICHLOROETHANE (DDT)

The Stiff and Castillo colorimetric test for DDT was extended to eighteen analogues and derivatives of DDT. The absorption maxima and extinction coefficients of the colored reactions were also obtained. The test is not specific for DDT. Of the compounds tested, the reaction was given by those having the structure > CHCX(3) or > C=CX(2.).     

A COLORIMETRIC METHOD FOR THE MICRO-DETERMINATION OF 2,2, BIS(P-CHLOROPHENYL) 1,1,1 TRICHLORETHANE (DDT)

A colorimetric method for the micro-determination of 2,2 bis(p-chlorophenyl) 1,1,1 trichlorethane (DDT) is presented. The test is based on the discovery that when DDT is heated in an anhydrous pyridine solution containing xanthydrol and solid potassium hydroxide a red color develops, which under proper conditions is proportional to the amount of DDT present. The reaction is sensitive to as little as 10 gammas of DDT. It will detect small differences in concentration within the range of 10 to 200 gammas. The test is relatively simple and can be run in a comparatively short time.     

江西省不同利用方式土壤DDT残留特征及生态风险评价

[目的]探究江西省不同利用方式土壤DDT残留特征及生态风险。[方法]利用GC-ECD检测江西省7种不同利用方式土壤中的DDTs残留。比较了不同利用方式土壤DDT残留水平,分析了DDT来源,评价了DDT生态风险。[结果]7种不同利用方式土壤DDTs残留量整体处于较低水平,其平均残留量为0.37μg/g。7种不同利用方式土壤DDTs残留量：桔树生长地土壤〉水稻种植地土壤〉茶树生长地土壤〉河滩草地土壤〉蔬菜种植地土壤〉板栗树生长地土壤〉棉花种植地土壤。DDT组分中,仅p.p′-DDT被检出,这表明7种土壤均有新的DDT污染源输入。生态风险评价表明,7种不同利用方式土壤中的DDTs对该地区鸟类、土壤生物及哺乳动物的风险较低。[结论]DDT对江西省农产品质量安全和人类健康存在潜在的威胁。