生物碳对除草剂污染的喀斯特坡耕地黄壤生态效应研究

本研究旨在探讨生物碳在喀斯特坡耕地黄壤中对除草剂污染的生态效应,通过田间试验和室内化验相结合的方法,研究生物碳添加对土壤化学特性、生物学特性等黄壤生态效应的影响。结果表明:添加生物碳显著降低黄壤中除草剂的生物有效性,改善土壤营养环境,提升土壤肥力,增加土壤微生物多样性,促进作物生长和降解和吸附除草剂,从而减少除草剂对作物的影响作用。

植被过滤带阻控除草剂污染的研究与应用进展

除草剂等农药在农业生产上作出了极大的贡献,但未被利用的农药因雨水和灌溉随地表径流进入水体,破坏了水生态系统,对人类健康构成威胁。本文对植被过滤带阻控除草剂污染的作用进行了阐述,综述了植被过滤带阻控除草剂污染的机理及影响其功能的主要因素,指出目前研究的局限和应用中应该考虑的问题,并对下一步研究方向进行展望。

利用转动物基因马铃薯消除土壤中的除草剂污染

Agricell Report 2003年40卷2期13页报道：山田及其同事(2002)研究了将大鼠的P450单加氧酶基因(CYP1A1)导人马铃薯(Solanum tuberosum)植株，藉以增强马铃薯代谢土壤中传播的污染物的能力。

烟嘧磺隆、莠去津残留污染微生物修复研究进展

世界人口增长导致粮食需求量提升,为了提高粮食产量,农田开始使用化学农药以解决粮食供求不平衡的问题。农药主要分为除草剂、杀虫剂、杀菌剂和植物生长调节剂等,除草剂的使用量约占农药使用量的三分之一,随着除草剂的大量使用,除草剂残留污染引发的相关问题引起了人们的重视,除草剂污染修复成为研究的热点问题,除草剂的微生物修复由于成本低、效果好、环境扰动小等优点成为近年除草剂污染修复研究的一大趋势。烟嘧磺隆、莠去津是我国北方地区常用玉米田除草剂,可防治多种杂草,但除草剂的使用造成的除草剂残留污染问题也会影响环境,危害人和动物的健康。本文介绍了除草剂残留污染的修复方法,介绍了微生物降解除草剂的方法和影响因素,概述了烟嘧磺隆、莠去津残留的危害及其降解菌株的降解条件和效果,最后指出除草剂残留污染微生物修复存在的问题并对未来的研究提出了展望。

淡水鱼类急性中毒的肉眼判断

鱼类的死亡可以由病害、缺氧、毒藻、机械损伤、污染中毒等多方面的原因造成。而污染中毒又包括农药中毒、重金属中毒、有机物中毒等几十种化学药物中毒。下面介绍几种淡水鱼类急性中毒的肉眼判断方法。

膳食安全的是是非非

近几年来餐桌污染可谓警报频传:先是疯牛病闹得人心惶惶,接着除草剂污染又被炒得沸沸扬扬,人们心头的阴影还没有完全消散,蛋糕致癌说“又吹皱一池春水”——致癌物丙烯酰胺潜流暗涌。那么,如何科学看待致癌物。

Atrazine Adsorption Behavior on a Fluvo-Aquic Soil as Influenced by Contact Periods

A batch experiment was performed to investigate nonequilibrium adsorption behavior of atrazine （2-chloro-4-ethylamino-6-isopropylamlno-1,3,5-triazlne） on a fluvo-aquic soil. The amount of atrazine sorbed increased with increasing adsorption contact periods. For a range of initial atrazlne concentrations, the percentage of atrazine sorbed within 24 h ranged from 24% to 77% of the observed total amount sorbed for the longest contact period; when adsorption contact periods were more than 72 h, the deviations in curves fitted using a nonlinear Freundllch equation gradually became less. The opposite trend was observed for the atrazine concentrations in solution. The effect of adsorption contact periods on atrazine adsorption behavior was evaluated by interpreting the temporal variations in linear and nonlinear Freundlich equation parameters obtained from the phase-distribution relationships. As the adsorption contact period increased, the nonlinear Freundlich capacity coefficient kf showed a significant linear increase （r^2 = 0.9063, P 〈 0.001）. However, a significant negative linear correlation was observed for the nonlinear coefficient n, a dimensionless parameter （r^2 = 0.5666, P 〈 0.05）. Furthermore, the linear distribution coefficient kd ranged from 0.38 to 1.44 and exhibited a significant linear correlation to the adsorption contact period （r^2 = 0.72, P 〈 0.01）. The parameters kf and n obtained from a time-dependent isotherm rather than the distribution coefficient kd estimated using the linear Freundlich equation were more appropriate to predict the herbicide residue in the field and thus more meaningful for environmental assessment.

Characterization of a Strain Capable of Degrading a Herbicide Mixture of Quinclorac and Bensulfuronmethyl

A bacterial strain,designated as LS,was isolated from a contaminated soil and was found to be capable of utilizing quinclorac,bensulfuronmethyl,and a mixture of the two as carbon and energy sources for growth. Strain LS was identified as Ochrobactrum sp. based on its physiological-biochemical properties,16S rDNA sequences,and phylogenetic analysis. The extent of degradation of quinclorac and bensulfuronmethyl at initial concentrations of 1.5 and 0.1 g L-1 was 90% and 67%,respectively,as measured by high performance liquid chromatography(HPLC) . When a herbicide mixture of 0.34 g L-1 quinclorac and 0.02 g L-1 bensulfuronmethyl was applied as carbon sources,quinclorac and bensulfuronmethyl were degraded at 95.7% and 67.5%,respectively. It appears that quinclorac is utilized more easily in a mixture than in a single state. The optimal temperature for growth of strain LS was 37 ℃. Strain LS grew well at pH 6 to 9 and had the highest degradation level for quinclorac and bensulfuronmethyl at an initial pH of 7 and 8,respectively. Addition of 0.25 g L-1 yeast extract could promote the growth and extent of degradation of quinclorac and bensulfuronmethyl by strain LS. Strain LS also showed the capability to degrade other aromatic compounds such as catechol,propisochlor,4-chloro-2-methylphenoxyacetic acid sodium(MCPA-Na) and imazethapy. The isolate LS shows a huge potential to be used in bioremediation for treating complex herbicide residues.

In Vitro Detection of Herbicide-Tolerant Fungi Isolated from Pesticides Polluted-Soil

Forty-five rhizofungal isolates were isolated, identified and characterized from 11 herbicides polluted-soil. Among the isolates, 10 fungal species proved to be the most potent and promising ones in herbicides tolerance. The herbicides exhibited severe and dramatic effect and modulation on fungal DNA and protein represented in DNA and protein profile. Severely loss in the total soluble cell ions （SCI） and total cell protein percentage （TCPC） concentrations were observed. The loss of SCI by glyphosate, Aspergillus flavus （86,30%） was the most affected one, followed by Penicillium spiculisporus （76,30%）, Penicilliurn verruculosum （64.40%） and Alternaria tenuissima （64%）, respectively. For pendimethalin, Alternaria tenuissima （54.01%） was the most affected fungi. For diclofop-methyl, Penicillium spiculisporus （74.20%） was the most affected fungi. The loss of TCPC by glyphosate, Alternaria tenuissima （64.71%） was the most effected fungi, followed by Penicillium spiculisporus （57.14%）, respectively. For pendimethalin, A. terreus （54.29%） w, as the most affected fungi. For diclofop-methyl, Penicillium spiculisporus （60%） was the most affected fungi, fbllowed by Alternaria tenuissima （58.82%）, Aspergillus tamarii （55.56%）, respectively. The results proved severe reductions and alteration in protein, SCI, TCPC and DNA in fungal strains exposed to these herbicides which might reflex a degree of tolerance occurred during the assimilation of those toxic compounds from the pesticides polluted-soil.

Efficiency and mechanism of degradation of alachlor in water by O_3/H_2O_2 catalyst system

Alachlor is used widely as a herbicide,but is an environmental endocrine disruptor. O 3/H 2O 2 system is used as catalyst to delve on the degradation efficiency of alachlor. The amount of the catalyst H 2O 2,the pH value of the soluble, the temperature and quality of water sample are changed to investigate the effect of these factors on the degradation of alachlor. The degradation of alachlor is qualitatively analyzed through their GS MS spectra and the possible mechanism of the degradation of alachlor is discussed as well.

Evaluation of Commercial Active Carbons for the Removal of s-Triazine Herbicides from Waters

The adsorption capacity of powdered active carbons, used in a water treatment facility, for the removal of the triazine herbicides propazine, prometryn and prometon, was evaluated. Kinetic studies showed that some of the carbon samples used could be suitable in the practice for the treatment of moderate contents of the herbicides in contaminated waters. Equilibrium studies showed that the data fit the Frumkin isotherm. The results show that in the adsorption process there are repulsive lateral interactions that depend mainly of the adsorbate molecules rather than the nature or distribution of adsorption sites. Such lateral interactions seem to be established mainly between the isopropyl groups of adjacent molecules, being of the same order for the three molecules. The effectiveness of the active carbons was evaluated by determining the percentage of reduction achieved by each product.

Review on Chlorobenzoic Acids Biodegradation and Their Environmental Impacts

Chlorobenzoic Acids are toxic organic compounds largely distributed in soils and sediments. They can be degraded to various products by microorgans. This paper is a review of the literature on biodegradability of the chlorobenzoic acids. The degradation pathways, degradation genes, role of transposable elements, and construction of strains are discussed. A brief introduction is given on the environmental impacts and the pollution control.

Predator-induced physiological responses in tadpoles challenged with herbicide pollution

Predators induce plastic responses in multiple prey taxa, ranging from morphological to behavioral or physiological changes. In amphibians, tadpoles activate plastic responses to reduce predation risk by reducing their activity rate and altering their morphology, specifically tail depth and pigmentation. Furthermore, there is now evidence that tadpoles＇ defenses are modi- fied when predators combine with other stressful factors such as pollutants or competitors, but our knowledge on the physiologi- cal responses underlying these responses is still scarce. Here we study physiological responses in Pelobates cultripes tadpoles exposed to a natural predator （larvae of the aquatic beetle Dytiscus circumflexus）, non-lethal concentrations of herbicide （gly- phosate, 0.5 mg/L and 1.0 mg/L） or both factors combined. We measured corticosterone levels, standard metabolic rate, oxidative damage （TBARS） and activity of antioxidant enzymes, and immune response （via leukocyte count）. Tadpoles reduced their corti- costerone concentration by ca. 24% in the presence of predator cues, whereas corticosterone did not change in the presence of glyphosate. Two enzymes involved in antioxidant response also decreased in the presence of predators （14.7% and 13.2% respec- tively） but not to glyphosate. Herbicide, however, increased the number of neutrophils and reduced that of lymphocytes, and had an interaction effect with predator presence. Standard metabolic rate did not vary across treatments in our experiment. Thus we show a marked physiological response to the presence of predators but little evidence for interaction between predators and low levels of herbicide. Multiple assessment of the physiological state of animals is important to understand the basis and conse- quences ofphenotypic plasticity