乙撑硫脲环境毒理研究进展

本文综合乙撑硫脲的环境毒理研究进展，内容包括乙撑硫脲残留分析方法，乙撑硫脲在施且代森类杀菌剂作物上的残留规律，代森类杀菌剂向乙撑硫脲的转化规律及其影响因素，乙撑硫脲的降解与代谢。乙撑硫脲的残留分析多要用衍生物气相色谱测定方法。乙撑硫脲具有“三致”作用。乙撑硫脲在施用代森类杀菌剂的作物及农产品残留量低，代森类杀菌剂在贮藏及农产品烹饪过程中可转化为乙撑硫脲，乙撑硫脲在环境中以光解为主，光敏物质可促进光     

硫代氨基甲酸酯类杀菌剂代森锰锌及其降解产物乙撑硫脲的技术进展研究

综述了国内外硫代氨基甲酸酯类杀菌剂代森锰锌及其降解产物乙撑硫脲的研究进展,详细介绍了代森锰锌和乙撑硫脲的性质,并对乙撑硫脲的降解研究进展、分析研究进展和残留动态研究进展进行了阐述.从中重点论述了食品中乙撑硫脲的多种分析检测技术,根据乙撑硫脲的性质分别选择气相色谱法和高效液相色谱法进行检测.总结了目前中国对该类农药的使用方式、方法,指出了硫代氨基甲酸酯类杀菌剂在农副产品以及在食品加工方面的研究方向.     

土壤有机质和活性铁组分对γ--666光解动力学的影响研究

研究了γ 6 6 6在有机碳含量分别为 <0 0 8% ,0 40 %± 0 0 6 %和 1 0 0 %± 0 2 8%而铁含量依次增加的三组土样中的光解动力学 ,γ 6 6 6的光解符合准一级动力学方程 .当土样中的铁含量相对不变时 ,γ 6 6 6的光降解动力学常数与有机质含量成负相关 ;而当土样中的有机碳含量相对不变时 ,光解动力学常数与铁含量成线性正相关 .为进一步验证土壤有机质对γ 6 6 6的光解的作用 ,采用土壤化学逐级分离法将一土样中的碳酸钙和有机质逐一去除而得到一级和二级土样 ,发现γ 6 6 6在这两级土样中的光解动力学常数依次为 0 0 12 9h-1和 0 0 2 31h-1,再次证明土壤有机质对γ 6 6 6的光解有明显抑制作用     

土壤污染及其防治

态环保协会一1994,13(6)一241~245 环信X一15 光解塑料在太阳光下铺晒可以降解成碎片,其分子量由277。。O降至5500。光解后的膜片以1:500浓度与土壤混告,对土壤物理性状产生了明显影响;对小麦、玉米、白菜的生长及产量,降吉一221一3,8丫scm处理组外,其它处理组均未显示不良影响。不改变土壤和作物中Cu、Cd、Ni等重金属的含量。土壤微生物能够在以光解后的碎片为唯一碳源的无机盐培养基上生长。图4表7参4X53 9502323碱性改良剂对富铝化淋溶土酸缓冲性能影响研究/吴杰民…(浙江农业大学环保系)//环境科学学报/中科院环委会一1994,14(4)一48…     

天然水体溶解性物质对5种抗生素光解的影响

建立了分析水体溶解性物质对抗生素光解影响的方法,对比研究了8种典型天然水体成分对3类5种抗生素光解的影响及其作用机制.结果表明,不同水体成分对不同抗生素光解影响呈现很大的差异性.甲砜霉素主要发生间接光解,纯水中光解速率只有1.33×10^-5min^-1,而其他抗生素则同时发生直接光解和间接光解.水体成分中NO₃^-,Fe²⁺和Cl^-主要通过光致活性物种（·OH和¹O₂）影响抗生素光解,DOM主要通过滤光作用影响抗生素光解.另外Ca²⁺和Mg²⁺对不同抗生素的光解影响主要通过其与抗生素分子的络合作用实现,Ca²⁺和Mg²⁺分别促进了恩氟沙星光解（0.3933min^-1和0.2314min^-1）,但一定程度上抑制了沙拉沙星的光解（0.0447min^-1和0.0289min^-1）.     

硫脲对酸性红壤 pH值与金属元素有效性的影响

通过实验室模拟,研究了不同浓度硫脲与尿素配施后,对酸性红壤的pH值及其金属元素有效性的影响.结果表明,土壤施加尿素后,其pH值有先升高后逐渐下降的趋势,而硫脲与尿素配施后,其pH值的下降趋势会受到抑制,尤其是当硫脲浓度达到5.0 mmol·kg-1时,土壤pH由最初的4.65上升到6.50以上,并在实验的中后期一直维持在6.0以上.硫脲和尿素配施后,Cu的有效态含量受硫脲浓度的影响较小,Zn、Al的有效态含量随着硫脲浓度的升高而降低,Mn的有效态含量在高浓度硫脲下,其含量保持在一个较高的水平,达到110 mg·kg-1以上.对于Cu、Zn和Al来说,在不同浓度硫脲和尿素配施后,其有效态含量与土壤的pH值呈现出明显的负相关.而对于Mn来说,在单施尿素的情况下,其有效态含量与土壤的pH值呈现出负相关,而在施入硫脲后,其有效态含量与土壤pH并没有呈现出明显的规律性.同时,研究结果还表明酸性红壤Al有效性随着土壤pH的升高而减小,当硫脲与尿素配合使用时,短期内土壤pH上升得更高,从而使得酸性红壤中Al的有效性减小.在硫脲和尿素配施后,土壤中Mn的有效态含量并不简单地取决于土壤的pH值,由于硫脲对Mn的络合作用和氧化还原作用,其含量受到土壤pH值和硫脲的共同影响.     

水环境中不同形态氮对甲芬那酸光降解影响机制的研究

研究了紫外光照射下水环境中不同形态的无机氮(NO-3、NO-2和NH+4)对甲芬那酸(MEF)光解的影响.NO-3与NO-2均促进MEF的光解,NH+4对MEF的光解基本无影响;在NO-3、NO-2存在下添加适量异丙醇,显著抑制MEF的降解,实验表明NO-3、NO-2在光照下产生了·OH并参与对MEF的氧化降解.同时模拟研究了水体处于不同p E值下,水中存在的不同形态的无机氮对MEF光解的复合影响,其对MEF光解促进作用不是简单的叠加关系,增大p E值,MEF的光解速率先增大后减小.当NO-2和NH+4共存时,对MEF的光解主要表现为NO-2的影响;当NO-2和NO-3共存时,两者对MEF的光解存在拮抗作用.     

新烟碱类农药在土壤中环境行为的研究进展

目前新烟碱类农药已占据了世界最大的杀虫剂市场份额,同时土壤是该类农药进入环境系统的源头,厘清其在土壤中的环境行为对探索新烟碱类农药的环境归趋和生态评价均具有重要的意义.本文总结并梳理了新烟碱类农药在土壤中主要环境行为的研究现状,包括吸附、解吸及降解行为;分析了农药本身性质、土壤成分及类型、pH值、温度、含水量等因子对该类农药吸附和解吸的影响机制;同时探讨了降解土壤新烟碱类农药的微生物菌群、光解和水解机理,并对新烟碱类农药未来的研究重点和方向提出了展望.     

表面活性剂对代表性磺胺类抗生素光解的影响

在水环境中表面活性剂与抗生素很可能会共存。为研究表面活性剂对磺胺类抗生素光解的影响,采用模拟日光及自然光照下的光解实验考察4种表面活性剂(CTAB、SDS、SDBS和TW80)对2种代表性磺胺类抗生素光解的影响。模拟日光及自然光下,4种表面活性剂均能促进磺胺嘧啶(SD)的光解,其中CTAB及SDBS促进效果最为显著。自然光下,CTAB显著促进磺胺异恶唑(SXZ)的光解,SDS、SDBS及TW80对SXZ光解的影响不大。在考察的p H值4、6、9条件下,CTAB均促进SD及SXZ的光解。研究表明,CTAB对SD和SXZ光解的影响并不是通过改变抗生素的p Ka和离子形态来实现的,其影响机制有待进一步研究。     

四环素在水体中的自然光解作用机制

近年来,抗生素引发的水体环境污染问题日益受到关注,光解是其在环境中消减的重要过程,但其中的关键机制及影响因素尚不明确.本研究系统地考察了初始浓度、pH以及无机离子、溶解性有机物等环境因子对四环素（TC）光解的影响,明确了自然光解的关键活性氧物种（ROS）,同时结合理论计算和降解产物的分析,揭示出了TC的自然光解路径及作用机制.结果表明,模拟自然光条件下TC可快速降解,5 μmol·L^-1 的TC在180 min内降解率为75.0%,符合一级反应动力学,反应速率常数为0.007 min^-1,远高于避光条件.随着TC初始浓度的上升,TC光解率和速率呈现出下降的趋势,并且碱性条件更有利于TC光解.水体中存在Cu（II）、Fe（III）和NO₃^-均能显著促进TC光解;富里酸（FA）则由于光屏蔽和淬灭作用对TC的光解产生显著抑制,但FA 和Fe（III）共存时,Fe（III）对光解的促进作用占主导.水体中TC的自然光解不仅存在直接光解,并且以超氧阴离子（O₂^-·）和羟基自由基（·OH）为关键ROS的自敏化光解在TC的光解过程中也起到重要作用.结合TC光解后的产物分析发现,发生间接光解后TC发生开环反应,相比于直接光解和自敏化光解降解地更充分.综上,TC在自然水体中的光解强烈受环境因素影响,可以通过增强活性氧介导的间接光解过程促进水体抗生素污染修复.     

农药在光照土壤层的迁移和降解

光照条件下 ,农药在土壤层中的降解速率不仅决定于光解本身 ,而且还是土层厚度、迁移过程的函数 .为此 ,描述了理解这些不同过程复合效果的理论框架 ,提出了允许实际光解过程和扩散过程分离定量的实验方案 ,同时进行了除草剂苄嘧磺隆在不同厚度土壤中的光解实验 ,并用数学模型评价了实验结果 .实验中确定了苄嘧磺隆在土壤中的实际光解速率常数 ,这个常数是不依赖于迁移动力学的 .     

Enhanced photodegradation of phenolic compounds by adding TiO2 to soil in a rotary reactor

Photodegradation ofpentachlorophenol （PCP） and p-nitrophenol （PNP） in soil was carried out in a designed rotary reactor, which can provide the soil particles with continually uniform irradiation, and on a series of thin soil layers. TiO2, as a kind of environmental friendly photocatalyst, was introduced to the soil to enhance the processes. Compared with that on the soil layers, photodegradation of PCP at initial concentration of 60 mg/kg was improved dramatically in the rotary reactor no matter whether TiO2 was added, with an increase of 3.0 times in the apparent first-order rate constants. The addition of 1 wt% TiO2 furthered the improvement by 1.4 times. Without addition of TiO2, PNP （initial concentration of 60 mg/kg） photodegradation rate in the rotary reactor was similar to that on the soil layers. When 1 wt% additional TiO2 was added, PNP photodegradation was enhanced obviously, and the enhancement in the rotary reactor was 2 times of that on the soil layers, which may be attributed to the higher frequency of the contact between PNP on soil particles and the photocatalyst. The effect of soil pH and initial concentrations of the target compounds on the photodegradation in the rotary reactor was investigated. The order of the degradation rate at different soil pH was relative to the aggregation of soil particles during mixing in the rotary reactor. Photodegradation of PCP and PNP at different initial concentrations showed that addition of TiO2 to enhance the photodegradation was more suitable for contaminated soil with higher concentration of PCP, while was effective for contaminated soil at each PNP concentration tested in our study.     

氯菊酯在不同质地土壤中的光降解动力学规律

为了研究氯菊酯在土壤中的光降解规律,更好地为其在自然环境中的降解提供理论依据,探讨了氯菊酯在不同质地土壤中,不同条件下的光降解动力学规律。结果表明:氯菊酯降解符合准一级动力学规律,氯菊酯的降解受土壤质地的影响较大,在不同土壤中降解率为:壤质砂土砂质壤土壤质黏土,日光比紫外光照射下腐殖酸对氯菊酯的降解影响明显,随着腐殖酸浓度的增加,它对氯菊酯的降解作用先促进后抑制。     

腐殖酸光敏化降解土壤中多环芳烃的动力学

多环芳烃化合物(PAHs)由于致癌、致畸和致突变而受到广泛关注。实验以多环芳烃菲(Phe)和芘(Pyr)为目标污染物,研究了腐植酸和紫外辐射强度对PAHs光降解动力学的影响,及腐植酸光敏化光降解土壤中PAHs的机制.结果表明,腐殖酸光敏化降解Phe和Pyr符合一级动力方程,随着腐殖酸投加量的增加,Phe和Pyr的动力学常数也逐渐增加,半衰期缩短,在添加0、10、20、30、40 mg/kg腐植酸后,Phe的半衰期分别为52.90、47.79、43.86、37.87、34.48 h,Pyr的半衰期分别为45.90、38.50、36.09、30.26、29.74 h;腐殖酸可以将吸收光能传递给土壤中Phe和Pyr使其发生敏化光解,也可以使Phe和Pyr发生光氧化反应;随着辐射强度的增加,PAH光降解速率增加。该研究为应用腐殖酸光敏化降解土壤中PAHs有机污染物提供了参考依据。     

Photocatalytic remediation of γ-HCH contaminated soil induced by α-Fe2O3 and TiO2

Heterogeneous photocatalytic degradation of γ-HCH on soil surfaces was carried out to evaluate the photocatalytic effectiveness of α-Fe2O3 and TiO2 toward degrading γ-HCH on soil surfaces. After being spiked with γ-HCH, soil samples were loaded with α-Fe2O3 or TiO2 and exposed to UV-light irradiation. Different catalyst loads(0%, 2%, 5%, 7%, and 10% (wt). α-Fe2O3; 0%, 0.5%, 1%, 2% wt. TiO2) were tested for up to 7 d irradiation. The effects of soil thickness, acidity, and humic substances were also investigated. The obtained results indicated that the γ-HCH photodegradation follows the pseudo-first-order kinetics. The addition of α-Fe2O3 or TiO2 accelerates the photodegradation of γ-HCH, while the photodegradation rate decreases when the content of α-Fe2O3 exceeds 7%(wt.). The degradation rate increases with the soil pH value. Humic substances inhibit the photocatalytic degradation of γ-HCH. Pentachlorocyclohexene, tetrachlorocyclohexene, and trichlorobenzene are detected as photodegradation intermediates, which are gradually degraded with the photodegradation evolution.     

环糊精在土壤有机污染物治理中的应用

综述了环糊精及其衍生物在土壤弱极性有机物治理中的应用和原理。环糊精可与土壤中弱极性有机污染物形成主客包合物,从而增加其水溶性促进其从土壤中解吸去除;能够同时去除金属离子;能够改变有机污染物理化性质促进其光解;可降低有机污染物毒性促进其微生物降解。     

Photocatalytic remediation of γ-hexachlorocyclohexane contaminated soils using TiO2 and montmorillonite composite photocatalyst

TiO2 and montmorillonite composite photocatalysts were prepared and applied in degrading γ-hexachlorocyclohexane （γ-HCH） in soils. After being spiked with γ-HCH, soil samples loaded with the composite photocatalysts were exposed to UV-light irradiation. The results indicated that the photocatalytic activities of the composite photocatalysts varied with the content of TiO2 in the order of 10%〈70%〈50% 〈30%, Moreover, the photocatalytic activity of the composite photocatalysts with TiO2 content 30% was higher than that of the pure P25 with the same mass of TiO2. The strong adsorption capacity of the composite photocatalysts and quantum size effect may contribute to its increased photocatalytic activities. In addition, effect of dosage of composite photocatalysts and soil pH on γ-HCH photodegradation was investigated. Pentachlorocyclohexene, trichlorocyclohexene, and dichlorobenzene were detected as photodegradation intermediates, which were gradually degraded with the photodegradation evolution.     

Effect of copper on the degradation of pesticides cypermethrin and cyhalothrin

The influence of coexisting copper (Cu) ion on the degradation of pesticides pyrethroid cypermethrin and cyhalothrin in soil and photodegradation in water system were studied.Serial concentrations of the pesticides with the addition of copper ion were spiked in the soil and incubated for a regular period of time,the analysis of the extracts from the soil was carried out using gas chromatography (GC).The photodegradation of pyrethroids in water system was conducted under UV irradiation.The effect of Cu~(2 ) on the pesticides degradation was measured with half life (t_(0.5)) of degradation.It was found that a negative correlation between the degradation of the pyrethroid pesticides in soil and Cu addition was observed.But Cu~(2 ) could accelerate photodegradation of the pyrethroids in water.The t_(0.5) for cyhalothrin extended from 6.7 to 6.8 d while for cypermethrin extended from 8.1 to 10.9 d with the presence of copper ion in soil.As for photodegradation,t_(0.5) for cyhalothrin reduced from 173.3 to 115.5 rain and for cypermethrin from 115.5 to 99.0 min.The results suggested that copper influenced the degradation of the pesticides in soil by affecting the activity of microorganisms.However, it had catalyst tendency for photodegradation in water system.The difference for the degradation efficiency of pyrethroid isomers in soil was also observed.Copper could obviously accelerate the degradation of some special isomers.     

不同源胡敏酸对磺胺嘧啶紫外光降解的影响及作用机制

研究了紫外光照条件下不同来源的胡敏酸（HA）,包括标准品胡敏酸（SPHA）、水稻土胡敏酸（SDHA）、泥炭土胡敏酸（NTHA）和落叶覆盖地胡敏酸（LYHA）对抗生素磺胺嘧啶（SDZ）光降解的影响以及主要活性物种对其光降解效能的贡献.结果表明：SDZ在纯水中及与HA共存条件下,其光降解过程均符合一级动力学模型,且HA对SDZ的光降解具有促进作用,其促进效果从大到小为SPHA > SDHA > NTHA > LYHA.通过羟基自由基（·OH）和单线态氧（¹O₂）淬灭实验发现,不同来源HA产生·OH和¹O₂的能力具有一定差异性.同等背景条件下,SPHA产生的·OH量相对较多,其对SDZ光降解的贡献率（26.97%）最大,而LYHA贡献相对较小（9.33%）.同时,¹O₂对SDZ光降解起主导作用,其降解贡献率为41.33%~51.95%.     

Photocatalytic remediation of γ-HCH contaminated soil induced by α-Fe2O3 and TiO2

Heterogeneous photocatalytic degradation of γ-HCH on soil surfaces was carded out to evaluate the photocatalytic effectiveness of α-Fe2O3 and TiO2 toward degrading γ-HCH on soil surfaces. After being spiked with γ-HCH, soil samples were loaded with α-Fe2O3 or TiO2 and exposed to UV-light irradiation. Different catalyst loads, 0%, 2%, 5%, 7%, and 10% (wt.)α-Fe2O3 ; 0%, 0.5%, 1%, 2:(Wt.)TiO2, were tested for up to 7 d irradiation. The effects of soil thickness, acidity, and humic substances were also investigated. The obtained results indicated that the γ-HCH photodegradation follows the pseudo-first-order kinetics. The addition of α-Fe2O3 or TiO2 accelerates the photodegradation of γ-HCH, while the photodegradation rate decreases when the content of α-Fe2O3 exceeds 7% (wt.).The degradation rate increases with the soil pH value. Humic substances inhibit the photocatalytic degradation of γ-HCH., and trichlorobenzene are detected as photodegradation intermediates, which are gradually degraded with the photodegradation evolution.