Cu Ni As Cr对萝卜出苗的影响

利用盆栽试验研究Ｃｕ、Ｎｉ、Ａｓ、Ｃｒ４个元素不同浓度对萝卜出苗的影响．结果表明，土壤含Ｃｕ５０ｍｇ／ｋｇ以上时，随着含Ｃｕ量的增加，出苗数随之减少．在酸性土壤上发生Ｃｕ和Ｎｉ危害时，可用提高土壤ｐＨ至中性的办法来消除．在中性土壤上，含Ｎｉ５０ｍｇ／ｋｇ以上对萝卜出苗有害．Ｃｕ、Ｎｉ复合污染比单一元素污染的危害大，且毒性Ｎｉ＞Ｃｕ．土壤Ｃｒ、Ａｓ含量越大，对萝卜出苗的危害也越大，并且毒性Ｃｒ（６＋）＞Ｃｒ（３＋）．     

市售绿茶自混合水溶液中吸附除去铬（Ⅵ）的研究

本文探讨了国产茶叶（市售云南产绿茶）的结构、成份和溶解，以及在不同浓度、时间、ｐＨ、温度的条件下，自混合溶液中大量吸附铬（Ⅵ）的特性。结果表明，浸泡过的茶叶对Ｃｒ（Ⅵ）的吸附率略低于未泡茶样，在一定条件下，Ｃｒ（Ⅵ）的吸附量可达到４．９６ｍｇ／ｇ。我们建议在这复杂体系中，用离子交换吸附过程形成表面配合物，以及发生化学作用的综合吸附机理来解释。     

DEHP在土壤和白菜中的残留及毒性分析

用聚氯乙烯（ＰＶＣ）塑膜覆盖白菜地，收获期土壤和白菜植株中ＤＥＨＰ的残留量分别为２．７３ｍｇ．ｋｇ＾－１和３．０５ｍｇ．ｋｇ＾－１。借鉴国外的评价指标，对人体食用白菜后的潜在危害进行了分析认为，人每天摄入干白菜中ＤＥＨＰ的量〈０．０５ｍｇ．ｋｇ＾－１，远低于人每天可接受ＤＥＨＰ的安全摄入量１ｍｇ．ｋｇ＾－１。     

重金属对蚯蚓的毒性毒理研究

通过室内模拟实验以及对株洲市重金属污染区农田土壤中采样，进行了重金属对蚯蚓的毒性毒理研究．毒性实验表明，各重金属元素４８ｈ的ＬＤ５０分别为：Ｃｄ１０００ｍｇ／ｋｇ，Ｐｂ８１２ｍｇ／ｋｇ，Ｃｕ６３３ｍｇ／ｋｇ，Ｈｇ３０４ｍｇ／ｋｇ，Ｚｎ５２８ｍｇ／ｋｇ，Ｃｒ４２８ｍｇ／ｋｇ．对蚯蚓毒理研究证明，重金属对蚯蚓酯酶同工酶有抑活作用，而重金属对蚯蚓过氧化物酶同工酶有激活作用．在光镜下观察，可见重金属污染可引起蚯蚓的体表溃疡及产生肿瘤，可使胃肠道粘膜层出血、背血管肿胀，同时可引起胃肠道粘膜上皮细胞产生萎缩或溃疡灶．蚯蚓特有的黄色细胞团污染程度不同而显示出消长规律．在电镜下可见到在重污染区的蚯蚓胃肠道粘膜上皮细胞中的ｒＥＲ肿胀、高尔基体膨大，线粒体嵴消失，甚至空泡化或解体．另可见细胞核膜间隙肿胀、断裂、核质外溢，胞质自溶．蚯蚓以上病变的大小是随土壤重金属污染区的污染级别而定；各病理变化指标均能定性地反映土壤重金属污染状况．     

O（^1D）与CF2ClBr的反应研究

本文研究了ＣＦ２ＣｌＢｒ－Ｏ３体系在２５３．７ｎｍ紫外光照下所引发的Ｏ（＾１Ｄ）与ＣＦ２ＣｌＢｒ的反应。Ｏ（＾１Ｄ）与ＣＦ２ＣｌＢｒ反应的最终产物为ＣＦ２Ｏ,Ｃｌ２,Ｂ２ｒ;实验中得到Ｏ（＾１Ｄ）与ＣＦ２ＣｌＢｒ的反应速率常数为１．０１×１０＾－１０ｃｍ＾３·ｍｏｌｅｃｕｌｅ＾－１·ｓ＾－１,并且对Ｏ（＾３Ｐ）与ＣＦ２ＬｌＢｒ的反应可能性以及Ｏ（＾１Ｄ）与ＣＦ２ＣｌＢｒ的反应机理进行了讨论。     

聚合氯化铝对水中微量铬（Ⅳ）的富集

本文研究了聚合氯化铝作为一种新的无机吸附共沉淀剂对水中微量铬（Ⅵ）的富集和测定，实验表明，它能有效地富集水中微量铬（Ⅵ），１．５ｇ聚合氯化铝在１０００ｍｌ溶液中（ｐＨ７－８，铬（Ⅵ）浓度０－５００μｇ／ｌ），搅拌速度在３００ｒ／ｍｉｎ左右，搅拌时间１０ｍｉｎ时，铬（Ⅵ）的吸附率在９５％以上，用分光光度法满意地实现了对河水中微量铬（Ⅵ）的测定。结果表明：铬（Ⅵ）的加入回收率≥９４％，测定的相对标准偏     

青霉菌BS—1还原Cr^6＋的条件及影响因子

青霉菌ＢＳ－１生长时还原Ｃｒ＾６＋的条件下：最适碳源为蔗糖或糊精，最适氮源是硫酸铵，最适温度３０℃，最适ＰＨ７．０，加入一定浓度的酵母浸出物可促进该菌对Ｃｒ＾＋的还原。不同预培养条件对该菌还原Ｃｒ＾６＋无明显影响，由此认为该菌对Ｃｒ＾６＋的还原是非诱导性的Ｈｇ＾２＋，Ｃｕ＾２＋，Ｃｏ＾２＋和Ｎｉ＾２＋对ＢＳ－１生长及Ｃｒ＾２｜还在有明显抑制作用，但在ρ（Ｎａ２ＳｅＯ４）＝１００ｍｇ／Ｌ时，则对该菌     

异丙隆在土壤和小麦中的降解与残留

在扬州和聊城两地进行了除草剂异丙隆在小麦上和麦田土壤中的残留动态和最终残留量试验，结果表明，异丙隆在小麦植株和土壤中消解较快，消解半衰期分别为３～４ｄ和８～１４ｄ；收获时小麦籽粒中异丙隆残留量小于０．０４ｍｇ／ｋｇ。推荐暂定异丙隆在小麦上ＭＲＩＬ值为０．５ｍｇ／ｋｇ。２５％异丙隆可湿性粉剂，按７．５ｋｇ／ｈｍ￣２用量，在次年早春（２月）使用，籽粒中异丙隆最终残留量不会超过ＭＲＬ值，对小麦是安全的。     

异丙隆在土壤和小麦中的降解与残留

在扬州和聊城两地进行了除草剂异丙隆在小麦上和麦田土壤中的残留动态和最终残留量试验，结果表明，异丙隆在小麦植株和土壤中消解较快，消解半衰期分别３－４ｄ和８－１４ｄ；收获时小麦籽粒中异丙隆残留量小于０．０４ｍｇ／ｋｇ。推荐暂定异丙隆在小麦上ＭＲＬ值为０．５ｍｇ／ｋｇ。２５％异丙性可湿性粉剂，按７．５ｋｇ／ｈｍ＾２用量，在次年早春使用，籽粒中异丙隆最终残留量不会超过ＭＲＬ值，对小麦是安全的。     

流动注射荧光分析法用于土壤及水系沉积物中铈（Ⅲ）含量的测定

研究表明Ｃｅ＾３＋在ｐＨ〈６．２ＫＣｌ介质中以２５４．０ｎｍ紫外光激发时，在３５２．０ｎｍ处发出具有恒定强度的荧光。因而可选择ｐＨ５－６作为测定酸度条件，利用Ａｌ２（ＳＯ４）３消除Ｆｅ＾３＋等离子的干扰，建立起Ｃｅ＾３＋的流动注射荧光分析法。方法的线性范围是２．０×１０＾－７—２．０×１０＾－６ｍｏｌ／ｌ，一元回归方程△Ｆ＝６６３６００Ｃ－０．０４１（ｎ＝１０，ｒ＝０．９９９７），检测限６．０×１     

含铬(Ⅵ)污水对地下水、土壤污染的研究

通过模拟含铬（Ⅵ）污水的土壤淋滤过程，结合受污染区域土壤垂直含铬分布分析，研究了含铬污水渗漏对地下水、土壤的污染。结果表明：含铬污水在亚粘土、亚砂土、砂土中的平均渗透系数分别为６．０２×１０－６ｃｍ／ｓ、３．８７×１０－４ｃｍ／ｓ、５．３２×１０－４ｃｍ／ｓ。含铬污水排放会在土壤中沉积铬，引起土壤污染，并污染地下水。     

磷酸盐对水稻土团聚体不同类型重金属镉、铬（Ⅵ）吸附的影响

利用低能量超声波分散、虹吸法沉降分离的方法分离不同粒径的水稻土团聚体颗粒，采用恒温振荡法研究不同浓度磷酸盐预处理的团聚体对Cd2+、Cr(Ⅵ)平衡吸附以及吸附动力学的影响。结果表明，砂粒级、粗粉砂级、粉砂级和粘粒级对P吸附量分别小于50、46、50和97 mg?kg-1，Cd2+吸附量低于未处理土样，P吸附量大于该数值，Cd2+吸附量高于未处理土样，团聚体吸附磷酸盐对Cd2+吸附量的影响，表现为低P吸附量抑制Cd2+的吸附，高P吸附量促进Cd2+的吸附，即随P吸附量增加Cd2+的吸附量呈波谷形变化；而团聚体吸附磷酸盐后对Cr(Ⅵ)的吸附则表现明显的抑制作用。磷酸盐预处理的团聚体对Cd2+、Cr(Ⅵ)吸附量大小顺序均为粘粒级>砂粒级>粗粉砂级>粉砂级，与有机质和游离氧化铁的含量顺序一致。团聚体对Cd2+的吸附过程分为快、慢两个阶段，快吸附阶段用一级动力学方程拟合最佳，而慢吸附时段用扩散方程和Elovich方程拟合最佳，表明吸附过程由不同的吸附因素控制。团聚体吸附磷酸盐后对Cd2+的吸附动力学常数增大。团聚体对Cr(Ⅵ)的吸附过程无明显快、慢阶段，对Cr(Ⅵ)吸附的整个过程用双常数速率方程和Elovich方程进行描述最佳，团聚体吸附磷酸盐后对Cr(Ⅵ)的吸附动力学常数减小。磷酸盐对土壤中重金属吸附的影响与金属离子类型以及磷吸附量有关，所以采用磷肥等含磷物质修复重金属污染土壤要注意金属离子的类型和磷肥的施用量。     

菲和铬(Ⅵ)单一及复合暴露对土壤微生物多样性的影响

有机物和重金属已成为我国土壤环境中常见的2类污染物质,二者间复合污染引起的土壤生态环境风险不容忽视。本研究以多环芳烃模式物菲和典型重金属铬(VI)作为受试物质,采用PCR-DGGE分子指纹图谱技术,探讨这2种污染物单一及复合暴露对土壤微生物群落多样性的影响,并选用主成分分析、聚类分析和戴斯系数3种算法对微生物群落相似性进行了比较。结果表明,在暴露实验第1天,菲单一暴露低浓度组中微生物群落相似性产生了极为明显的变化,而到第7天时,菲和铬(VI)单一暴露高浓度组均对微生物群落结构相似性产生最大程度的影响;采用香农指数法评价微生物群落的多样性,发现在暴露实验第7天,菲和铬(VI)单一暴露高浓度组对微生物群落多样性的影响比复合暴露高浓度组更强,二者复合暴露的相互作用方式表现为拮抗效应。本研究证明低浓度菲短期暴露的效应高于高浓度暴露结果,因而多环芳烃菲自身及其在复合暴露中所扮演的角色尤其值得关注。     

Catalytic determination of ultratrace chromium based on gallocyanine‐hydrogen peroxide indicator reaction

A highly sensitive catalytic procedure for the determination of ultratrace chromium(VI) was developed based on its catalytic effect on the oxidation of gallocyanine by hydrogen peroxide in hexamine‐hydrochloric acid buffer solution. The reaction was followed spectrophotometrically by measuring the rate of change in the absorbance at 620 nm. The apparent active energy of the catalytic reaction is 6.84 kJ . mol^‐1. The calibration graph is linear for 0–150 ng.ml^‐1, and the detection limit is 0.8 ng.ml^‐1. Most foreign ions have no interfering effect on the determination of chromium(VI) except for Al³⁺, Cu²⁺, Fe³⁺and Fe²⁺. The interference of Al³⁺ is eliminated by masking with F^‐, and those of Cu²⁺, Fe³⁺ and Fe²⁺ are eliminated by adding appropriate amount of EDTA. The present procedure had been used for the determination of trace chromium(VI) in lake water, mine water and electroplating wastewater, and the results were satisfactory.     

Biochemical speciation in chromium genotoxicity

The biochemical speciation of chromium compounds in mammalian cells is discussed with respect to uptake, metabolism, DNA binding and damaging. Whereas soluble hexavalent chromium is taken up rapidly and accumulated intracellularly after its reduction, compounds of trivalent chromium penetrate biomembranes about three orders of magnitude slower. Cr(VI) after its uptake is metabolised by electron donating compounds via Cr(V) to Cr(III) compounds. Chromium from various Cr(III) compounds, but not chromate, binds to chromatin in isolated cell nuclei. The DNA‐protein crosslinks and DNA strand breaks observed in rat liver and kidney after chromate administration are also found in vitro, when Cr(III) compounds (but not chromate) interacts with isolated nuclei. In the Chinese Hamster cell HGPRT mutation assay, three out of four tested Cr(III) complexes were found to be mutagenic. In a direct DNA strand break assay with supercoiled bacteriophage PM 2 DNA, neither chromate nor the four Cr(III) compounds tested caused nicks. However, the combined action of chromate plus glutathione as well as the isolated complex of pentavalent chromium, Na₄Cr(glutathione)₄, did cause DNA breaks. Reactive oxygen species are inferred to be the ultimate DNA nicking agents in this assay. In conclusion there appear to be two mechanisms of chromate genotoxicity; one with direct DNA damage caused by Cr(V) species and one via DNA‐protein crosslinks formed with Cr(III), the final reduction state of chromate.     

Absorption and retention of polydimethylsiloxanes (silicones) in fish: Preliminary experiments†

Hydrophobicity and bioaccumulation potential of linear and cyclic polydimethylsiloxane (PDMS) oligomers were estimated by reversed‐phase liquid chromatography and feeding experiments with guppies (Poecilia reticulata). PDMS concentrations in fish were determined by capillary column gas chromatography and gas chromatography‐mass spectrometry. In contrast to polychlorinated biphenyls (PCBs), only very small amounts of PDMS were retained by the fish after six weeks feeding.     

酸雨淋溶对铬渣中Cr6+释放的影响

采用人工柱对3个不同年代的铬渣进行为期5年不同pH值(4.0,5.0,6.0)下的模拟酸雨淋溶实验,结果表明:淋溶前铬渣具有很强的腐蚀性,pH值达到12以上,总铬和Cr6 分别占铬渣的4.68%-4.86%和1.19%-1.73%;Cr6 溶出浓度在淋溶初期大,随着淋溶时间的增加,溶出浓度急剧下降,淋溶接近第二年雨量时,溶出浓度减小且趋于稳定.5年模拟酸雨淋溶后,Cr6 累积溶出范围在2138-4490mg,浸出液浓度稳定范围50-127mg·l-1,仍然远高于排放标准.铬渣淋溶后,残渣态和结晶铁锰氧化物结合态铬含量保持不变,水溶态、酸溶态和稳定铁锰氧化物结合态铬有不同程度减小.     

1,3,5-triazine-triethylenetetramine polymer: an efficient adsorbent for removal of Cr(VI) ions from aqueous solution

The synthesis of 1,3,5-triazine-triethylenetetramine (TATETA), its characterization by infrared spectroscopy and elemental analysis, and its application for removal of Cr(VI) ions from aqueous solution is reported. The effects of pH, contact time, initial concentration of Cr(VI), sorbent dose, and temperature on adsorption were investigated and optimized by batch adsorption experiments. Adsorption was highest at acidic conditions with an equilibration time of 25 min. The adsorption followed a Langmuir model, with an adsorption capacity of 303 mg g^?1, was second order in its kinetics, and exothermic and thus spontaneous.     

Biosorption potential of Cr(VI) by Kocuria sp. ASB107, a radio-resistant bacterium isolated from Ramsar,Iran

Heavy metal pollution in soil and wastewater is a worldwide environmental issue in which microorganisms play a significant role for its removal. In the present study, biosorption of Cr(VI) by the live and dead cells of Kocuria sp. ASB107, a radio-resistant bacterium, was investigated. The effect of contact time, solution pH, initial hexavalent chromium concentration and adsorbent dose on biosorption efficiency was studied. Also, live cells were further immobilised on various matrices by different techniques and then were examined for tolerance to chromium biosorption. Experimental results indicated that the removal efficiency of chromium increased with decrease in pH, initial Cr(VI) concentration, and also increase in adsorbent dose and the contact time. The maximum removal efficiency of live and dead cells at acidic pH of 4–4.5, contact time of 24 hours, adsorbent dose 1.6?g/100?mL and initial chromium concentration 25?mg/L were 82.4% and 69.2%, respectively. The adsorption data was described well by Langmuir isotherm model. Among all immobilisation techniques tested, cross-linking showed the highest biosorption of Cr(VI). Results indicated that live cells of Kocuria sp. ASB107 were better than dead ones.