北京某污水处理厂及受纳水体中典型有机磷酸酯的污染特征和风险评估

有机磷酸酯(organophosphate esters, OPEs)在环境中普遍存在,对生态系统和人体健康构成潜在的风险.在优化固相萃取(SPE)前处理方法的基上,建立了超高效液相色谱-质谱联用(UPLC-MS/MS)测定水体中8种OPEs的检测方法.实验对比了不同SPE小柱、不同洗脱液和不同洗脱液体积对8种目标化合物的回收率.结果发现,使用ENVI-18柱富集OPEs,用8 mL含25%(体积分数)二氯甲烷的乙腈洗脱,目标化合物加标回收率在92.5%～102.2%.不同基质样品加标回收率为88.5%～116.1%,RSD为1.7%～9.9%.对北京某污水处理厂不同工艺和污水受纳河流水体上下游连续6 d取样检测,污水厂出水中OPEs的浓度范围为85.9～235.4 ng·L~(-1),受纳河流下游的6 d OPEs平均浓度为130.3 ng·L~(-1),高于上游来水中浓度(119.4 ng·L~(-1)),但低于污水处理厂出水平均总浓度(162.5 ng·L~(-1)).结果表明,污水处理厂不能完全去除OPEs,对磷酸三乙酯(TEP)和磷酸三(2-乙基己基)酯(TEHP)存在负去除现象,对其它OPEs的去除率在14.1%～84.9%之间,污水处理厂对总∑OPEs去除率为50.0%.污水处理厂出水中磷酸三苯酯(TPhP)存在中等风险(RQ0.10),其他有机磷酸酯的环境风险较低(RQ0.10),但其长期混合作用对受纳河流生态系统产生的生态危害不容忽视.     

设施栽培对土壤与蔬菜中PAHs污染特征及其健康风险评价

利用现场设施栽培试验,研究了大棚内外土壤、蔬菜(生菜、苋菜、空心菜和青菜)及蔬菜生长期内湿沉降样品中16种PAHs的含量特征、可能来源以及对人的健康风险.结果表明,大棚内外蔬菜中PAHs含量平均值分别为99.27 ng·g~(-1)和109.11 ng·g~(-1);棚内外土壤中PAHs含量分别为128.01 ng·g~(-1)和173.07 ng·g~(-1).棚内PAHs含量明显低于棚外,棚内外土壤与蔬菜体内的PAHs均以低环为主.湿沉降颗粒态与溶解态PAHs含量分别为2 986.49 ng·g~(-1)和61.9 ng·L~(-1).通过分析蔬菜对土壤中PAHs的生物富集系数发现蔬菜对低环PAHs富集系数较大.土壤与蔬菜中PAHs主要来源为石油排放和草、木和煤的燃烧;湿沉降颗粒态中PAHs主要来源为油类排放与草、木和煤的燃烧;溶解态主要来源为化石燃料的燃烧和汽油排放.分析终身暴露致癌风险,儿童与成人食用不同种类蔬菜的终身暴露致癌风险值ILCR在10-6~10-4(排除苋菜)之间,都存在潜在致癌风险,棚外蔬菜致癌风险高于棚内,相比较其他3种蔬菜食用苋菜(ILCR10-6)的致癌风险最低,青菜的终身暴露风险ILCR10-5,有较高的致癌风险.     

成都饮食中全氟化合物的污染特征及健康风险评估

为了解成都市居民通过饮食暴露于全氟化合物(Perfluoroalkyl Substances, PFASs)的情况,本研究通过调查统计成都市居民的主要饮食情况,选取米、蔬菜、牛奶、鸡蛋、鱼和猪肉6类饮食为研究对象,采用超高效液相色谱-串联质谱法对样品中17种PFASs进行检测.结果显示,所有饮食中均检出PFASs,说明PFASs在饮食中普遍存在.鸡蛋中的∑PFASs含量最高,达(155±25.4) ng·g~(-1)(湿重,下同);白菜的∑PFASs含量最低,仅为(0.101±0.026) ng·g~(-1).大部分样品中以全氟辛烷羧酸(Perfluroroocantanoic Acid,PFOA)为主,其次为短碳链的全氟羧酸(Perfluoroalkyl Acids,PFCAs).其中,鸡蛋蛋黄中∑PFASs的含量为(600.0±98.6) ng·g~(-1),远高于蛋清中的含量(0.606±0.101) ng·g~(-1),且蛋黄中主要为全氟辛烷磺酸(Perfluorooctane Sulfonate,PFOS)(98.1%).通过风险评估可以得出,成都市居民对PFOS和PFOA的日摄入量分为85.6 ng·kg~(-1)·d~(-1)和4.38 ng·kg~(-1)·d~(-1),低于欧盟食品安全局推荐的每日最大摄入量,不会对成都市居民造成即时伤害.     

有机磷酸酯在重庆不同城市功能区土壤的分布特征及来源

本研究利用超高效液相色谱飞行时间质谱(UPLC-Q-TOF~-MS)检测分析了重庆市4个不同功能区城市表层土壤中12种有机磷酸酯(organophosphate esters,OPEs)含量水平,探讨了其组成特征,通过相关性分析讨论了土壤有机质(soil organic matter,SOM)与ΣOPEs及各单体含量之间的关系,利用主成分分析阐述了OPEs可能的来源.结果表明,ΣOPEs含量(以干重计,下同)范围为10. 7～108 ng·g~(-1),平均值为46. 4 ng·g~(-1),处于国内外较低水平;不同功能区土壤中ΣOPEs平均含量大小依次为:工业区(55. 6 ng·g~(-1)),住宅区(55. 5 ng·g~(-1)),商业区(41. 8 ng·g~(-1)),城市公园(34. 1 ng·g~(-1)).磷酸三(2-氯异丙基)酯(TCPP)和2-乙基己基二苯基磷酸酯(EHDPP)是主要OPEs污染物单体,TCPP在工业区土壤贡献率最高达到了31. 5%,而EHDPP在商业区和城市公园贡献率最高分别为23. 4%和24. 7%.相关性分析表明SOM含量和ΣOPEs含量呈显著相关(P 0. 05),和单体磷酸三甲苯酯(TCP)含量呈极显著相关(P 0. 01),表明SOM是影响OPEs分布的因素之一.主成分分析表明城市土壤OPEs来源并不单一,污水灌溉、路面径流、室内源污染及污泥再利用等都可能成为土壤OPEs潜在来源途径.     

松花江表层沉积物PAEs分布特征及生态风险评价

为揭示松花江干支流表层沉积物中邻苯二甲酸酯类(phthalate esters,PAEs)的空间分布特征及其生态风险状况本文利用气相色谱三重四级杆质谱联用仪(GC-MS)对松花江干支流表层沉积物中6种PAEs的含量分布和组成特征进行了分析,并采用商值法和环境风险水平(ERL)法对其生态风险状况进行评价.结果表明:①松花江干支流沉积物6种邻苯二甲酸酯(∑_6PAEs)含量范围(以干重计)为6 832.5～36 298.9ng·g~(-1)(平均值为18388.6ng·g~(-1)),邻苯二甲酸(2-乙基己基)酯(DEHP)和邻苯二甲酸二丁酯(DBP)为主要组分,干流点位∑_6PAEs含量(6 832.5～36 298.9 ng·g~(-1),平均值为18 616.9ng·g~(-1))与支流点位∑_6PAEs(10 367.6～26 593.3ng·g~(-1),平均值为18 264.1ng·g~(-1))差异不显著(P0.05),支流点位各PAEs单体含量与干流点位差异不大.从上游到下游干支流∑_6PAEs含量呈现先降后升的趋势.农业自然区域∑_6PAEs平均含量(18 677.5 ng·g~(-1))与城市工业区域(18 063.7 ng·g~(-1))相近(P0.05),DBP和DEHP是两区域内的主要PAEs两者平均值贡献率高达98%以上.②松花江干支流表层沉积物中∑_6PAEs主要来源于人类日用品、农业生产以及含有增塑剂的工业生产.③松花江表层沉积物中DMP和BBP对水生生物无生态风险,DEP具有低水平生态风险,而DEHP和DBP对水生生物具有高生态风险.     

地表水体中同时分析18种糖皮质激素方法的建立

建立了一种采用固相萃取-超高效液相色谱串极质谱联用系统(UPLC-MS/MS)同时测定地表水体中18种糖皮质激素的高灵敏分析方法.样品经过HLB固相萃取柱富集净化、V(乙腈)/V(乙酸乙酯)=1∶1,洗脱后,用UPLC-MS/MS测定.流动相为甲醇和0.1%乙酸水溶液(体积比),采用梯度洗脱,实现了18种目标物质的基线分离,线性范围为1.0~1 000μg·L-1.实际水样的加标回收率为65%~108%.整个分析的方法检出限(MDL)除醋酸可的松和醋酸氢化可的松为10 ng·L-1外,其他均在0.10 ng·L-1和1.0 ng·L-1之间.应用此方法于北京地表水体5个样品,检测到8种糖皮质激素,浓度范围0.20~476ng·L-1,其中曲安西龙、曲安奈德、醋酸氢化可的松和丙酸氯倍他索在地表水中首次检出,证明了该方法的有效性.     

截污调水后滇池表层沉积物中16种PAHs的分布特征

截污调水等工程实施后,滇池的外源污染已得到有效控制,表层沉积物等内源污染物应加以重视.为研究滇池表层沉积物中16种多环芳烃(PAHs)的分布特征,采用气相色谱-质谱联用法(GC-MS)分析了2016年12月采集的19个滇池表层沉积物样品的PAHs含量,解析其时空分布规律、来源及生态风险.滇池表层沉积物中总多环芳烃(TPAHs)的含量范围为92. 31～1 546. 78 ng·g~(-1),平均值为496. 30 ng·g~(-1),草海TPAHs含量(平均932. 37 ng·g~(-1))远高于外海(平均380. 02ng·g~(-1)),随着截污调水工程的开展,TPAHs含量较2012年大幅下降,已处于我国重点水域中较低水平.滇池表层沉积物中含量最高的物质为荧蒽(80. 65 ng·g~(-1)),毒性当量(TEQ)含量最高的物质为二苯并[a,h]蒽(42. 97 ng·g~(-1)). PAHs组成以4环及5～6环为主(分别占总含量的40. 38%和40. 22%),PAHs构成较以往大体一致.分子比值法分析结果表明,滇池表层沉积物中PAHs主要由生物质或煤的燃烧贡献.基于潜在生态风险标志对比法评估,全湖总体处于低风险水平,但草海的生态风险相对较高,值得进一步关注.本研究结果可为滇池水质的保持与提升提供基础数据和重要参考.     

塑胶跑道中有机磷酸酯的含量及健康风险

采用超声萃取-层析净化-气相色谱/质谱联用仪定量分析塑胶跑道中7种有机磷酸酯(OPEs),方法回收率为71.41%~110.58%,标准曲线相关系数r0.99,质控良好.采集并分析了成都市12个学校内的塑胶跑道样品中OPEs的含量及分布.结果表明2/3学校内的塑胶跑道样品中检出了OPEs,其中磷酸三正丁酯[tri-n-butyl phosphate,TnBP]、磷酸三异辛酯[tris(2-ethylhexyl)phosphate,TEHP]的检出率较高,而磷酸三(2-氯乙基)酯[tri(2-chloroethyl)phosphate,TCEP]、磷酸三(1,3-二氯异丙基)酯[tridichloropropyl phosphate,TDCPP]、磷酸三苯酯[triphenyl Phosphate,TPh P]在所有样品中均未检测到.Σ7OPEs含量范围为ND~534.89 ng·g~(-1),其中单体含量最高的是TnBP(ND~462.18 ng·g~(-1)).一个样品中检出了毒性较大的氯代磷酸酯-TCPP[trichloropropyl phosphate],含量为205.94 ng·g~(-1).成人和儿童通过皮肤接触摄入的Σ7OPEs日均暴露剂量(以bw计)最高,分别为0.14 ng·(kg·d)~(-1)和0.64 ng·(kg·d)~(-1),儿童的日均暴露剂量明显高于成人.成人及儿童的风险熵值(RQ)为10~(-7)~10~(-5).建议政府对塑胶跑道中OPEs使用量及添加种类进行管控,以更好地保护人群健康.     

制革废水处理过程中磺胺类抗生素和抗性细菌的分布特征

针对两家制革厂废水处理过程中3种磺胺类抗生素和磺胺类抗性细菌的丰度和分布特性以及两个不同工艺污水处理厂对抗生素的去除规律做了相关研究.结果表明,3种抗生素在两家制革污水处理过程中均有检出,水样中3种抗生素的总质量浓度在59.1~706.7 ng·L~(-1)之间;两家制革厂废水处理剩余污泥中3种抗生素的总含量分别为4 388 ng·kg~(-1)和2 979.4ng·kg~(-1),与市政污水处理厂中的抗生素含量相差不大.不同的污水处理工段对3种抗生素去除效果不同,但去除效率均大于70%.生物处理单元对抗生素的去除率相对较高,而厌氧池是去除抗生素的主要阶段(去除率50%).两个制革厂的进出水和剩余污泥中共筛选出8株抗性细菌,这8个分离菌株可分为5个菌属.进出水中的抗性细菌含量介于9.37×10~3~5.08×10~5CFU·mL~(-1)之间,剩余污泥中的磺胺类抗性细菌含量较高分别为1.17×10`7CFU·g~(-1)和7.2×10~6CFU·g~(-1).两个制革污水处理厂对磺胺甲唑抗性细菌的去除率分别达到了1.34 log和2.15 log.     

滇池流域宝象河水库沉积物中多环芳烃的垂直分布特征及来源解析

采用GC-MS检测了滇池宝象河水库沉积物中16种美国环保署(US EPA)优先控制的多环芳烃(PAHs)的含量,并对其垂直分布特征及来源进行分析,以此了解宝象河水库近年来PAHs的变化.结果表明,水库沉积物中16种PAHs均有检出,其含量范围为162.26~762.24ng·g~(-1),平均值为423.30 ng·g~(-1).自底层50 cm至表层,沉积物中PAHs含量呈上升趋势.从多环芳烃环数来看,沉积物中的PAHs以2~3环为主,其含量为128.34~518.81 ng·g~(-1),平均值为279.88 ng·g~(-1),占PAHs总量的42.2%~84.1%,平均值为67.6%.FLA/(FLA+PYR)、Ba A/(Ba A+CHR)和Icd P/(Icd P+Bghi P)3组比值及PAHs各组分的分析结果表明,燃烧过程是沉积物中PAHs的主要来源,主要为煤炭、生物质的燃烧.PAHs含量与总有机碳(TOC)之间有显著正相关关系,TOC影响宝象河水库沉积物中PAHs的分布.     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.     

Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

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Single and joint effects of pesticides and mercury on soil urease

The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase （up to 13%-21%） in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship （P〈0.05） between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose （ED50） values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.     

Isolation and preliminary characterization of a 3-chlorobenzoate degrading bacteria

A study was conducted to compare the diversity of 2-, 3-, and 4-chlorobenzoate degraders in two pristine soils and one contaminated sewage sludge. These samples contained strikingly different populations of mono-chlorobenzoate degraders. Although fewer cultures were isolated in the uncontaminated soils than contaminated one, the ability of microbial populations to mineralize chlorobenzoate was widespread. The 3- and 4-chlorobenzoate degraders were more diverse than the 2-chlorobenzoate degraders. One of the strains isolated from the sewage sludge was obtained. Based on its phenotype, chemotaxonomic properties and 16S rRNA gene, the organism S-7 was classified as Rhodococcus erythropolis. The strain can grow at temperature from 4 to 37℃. It can utilize several （halo）aromatic compounds. Moreover, strain S-7 can grow and use 3-chlorobenzoate as sole carbon source in a temperatures range of 10-30℃ with stoichiometric release of chloride ions. The psychrotolerant ability was significant for bioremediation in low temperature regions. Catechol and chlorocatechol 1,2-dioxygenase activities were present in cell free extracts of the strain, but no （chloro）catechol 2,3- dioxygenase activities was detected. Spectral conversion assays with extracts from R. erythropolis S-7 showed accumulation of a compound with a similar UV spectrum as chloro-cis,cis-muconate from 3-chlorobenzoate. On the basis of these results, we proposed that S-7 degraded 3-chlorobenzoate through the modified ortho-cleave pathway.     

Organochlorine pesticides in soils under different land usage in the Taihu Lake region, China

A field study was conducted in the Taihu Lake region, China in 2004 to reveal the organochlorine pesticide concentrations in soils after the ban of these substances in the year 1983. Thirteen organochlorine pesticides (OCPs) were analyzed in soils from paddy field, tree land and fallow land. Total organochlorine pesticide residues were higher in agricultural soils than in uncultivated fallow land soils. Among all the pesticides, ΣDDX (DDD, DDE and DDT) had the highest concentration for all the soil samples, ranging from 3.10 ng/g to 166.55 ng/g with a mean value of 57.04 ng/g and followed by ΣHCH, ranging from 0.73 ng/g to 60.97 ng/g with a mean value of 24.06 ng/g. Dieldrin, endrin, HCB and α-endosulfan were also found in soils with less than 15 ng/g. Ratios of p,p'-(DDD DDE)/DDT in soils under three land usages were: paddy field ＞ tree land ＞ fallow land, indicating that land usage inlfuenced the degradation of DDT in soils. Ratios of p,p'-(DDD DDE)/DDT ＞1, showing aged residues of DDTs in soils of the Taihu Lake region. The results were discussed with data from a former study that showed very low actual concentrations of HCH and DDT in soils in the Taihu Lake region, but according to the chemical half-lives and their concentrations in soils in 1980s, the concentration of DDT in soils seemed to be underestimated. In any case our data show that the ban on the use of HCH and DDT resulted in a tremendous reduction of these pesticide residues in soils, but there are still high amounts of pesticide residues in soils, which need more remediation processes.     

Sorption of 1-naphthol by plant cuticular fractions

The contribution of aliphatic-rich plant biopolymer to sorption of hydrophobic organic compounds is significantly important because of their preservation and accumulation in the soil environment,but sorption mechanism is still not fully understood.In this study, sorption of 1-naphthol by plant cuticular fractions was examined to better understand the contributions of respective fraction.Toward this end,cuticular materials were isolated from the fruits of tomato by chemical method.The tomato cuticle sheet consisted of waxes (6.5 wt%),cuticular monomer (69.5 wt%),and polysaccharide (24.0 wt%).Isotherms of l-naphthol to the cuticular fractions were nonlinear (N value (0.82-0.90)) at the whole tested concentration ranges.The KodKow ratios for bulk cuticle (TC1),dewaxed cuticle (TC2),cutin (TC4),and desugared cuticle (TC5) were larger than unity,suggested that tomato bulk cuticle and cutin are much powerful solption medium.Sorption capability of cutin (TC4) was 2.4 times higher than the nonsaponifiable fraction (TC3).The 1-naphthol interactions with tomato cuticular materials were governed by both hydrophobic-type interactions and polar (H-bonding) interactions. Removal of the wax and polysaccharide materials from the bulk tomato cuticle caused a significant increase in the sorption ability of the cuticular material.There was a linear negative trend between K_(oc) values and the amount of polysaccharides or fraction's polarities ((N O)/C);while a linear positive relationship between K_(oc) values and the content of cutin monomer (linear R~2=0.993) was observed for present in the cuticular fractions.Predominant sorbent of the hydrophobic organic compounds (HOCs) in the plant cuticular fraction was the cutin monomer,contributing to 91.7% of the total sorption of tomato bulk cuticle.     

Alterations of organ histopathology and metallolhionein mRNA expression in silver barb, Puntius gonionotus during subchronic cadmium exposure

Common silver barb,Puntius gonionotus,exposed to the nominal concentration of 0.06 mg/L Cd for 60 d,were assessed for histopathological alterations(gills,liver and kidney),metal accumulation,and metallothionein(MT)mRNA expression.Fish exhibited pathological symptoms such as hypertrophy and hyperplasia of primary and secondary gill lamellae,vacuolization in hepatocytes,and prominent tubular and glomerular damage in the kidney.In addition,kidney accumulated the highest content of cadmium,more than gills and liver.Expression of MT mRNA was increased in both liver and kidney of treated fish.Hepatic MT levels remained high after fish were removed to Cd-free water.In contrast,MT expression in kidney was peaked after 28 d of treatment and drastically dropped when fish were removed to Cd-free water.The high concentrations of Cd in hepatic tissues indicated an accumulation site or permanent damage on this tissue.     

Seed selections for crystallization of calcium phosphate for phosphorus recovery

Seed induces and promotes the crystallization of calcium phosphate, and acts as carrier of the recovered phosphorus （P）. In order to select suitable seed for P recovery from wastewater, three seeds including Apatite （AP）, Juraperle （JP） and phosphate-modified Juraperle （M-JP） were tested and compared. Batch and fixed-bed column experiments of seeded crystallization of calcium phosphate were undertaken by using synthetic wastewater with 10 mg/L P phosphate. It shows that AP has bad enduring property in the crystallization process, while JP has better performance for multiple uses, and M-JP is a hopeful seed for P recovery by crystallization of calcium phosphate.