苯并（a）芘对罗非鱼（GIFT Oreochromis niloticus）肝细胞DNA损伤的影响

苯并（a）芘（Benzo（a）pyrene,BaP）是一种含有5个苯环的多环芳烃,是环境中广泛存在的一类有机污染物,苯并（a）芘可引起多种形式的DNA损伤。彗星试验,又称为单细胞凝胶电泳（Single Cell Gel Electrophoresis,SCGE）,是一项灵敏、快速的在单细胞水平检测DNA链断裂的技术,已经广泛应用于水环境的生物监测中。污染物的毒性监测与评估一直是环境科学研究的热点问题之一。本文通过生态毒理学试验,利用单细胞凝胶电泳技术,研究不同浓度苯并（a）芘暴露对罗非鱼（GIFT Oreochromis niloticus）肝细胞DNA的损伤情况。试验将罗非鱼在0.1、1、10、50μg·L-14个苯并（a）芘（BaP）浓度下分别暴露4、7、14 d,利用彗星试验研究BaP对罗非鱼肝细胞DNA的损伤情况,以尾部DNA含量、尾长、尾矩及Olive尾矩为评价指标,结果表明,BaP会对肝细胞DNA造成不同程度的损伤：在0.1、1、10μg·L-13个浓度组,DNA损伤随着BaP暴露浓度的增加而增加,呈现一定的剂量效应关系,50μg·L-1组DNA损伤有所下降。在时间上,除1μg·L-1剂量组的尾部DNA含量、10μg·L-1组的尾部DNA含量及Olive尾矩外,其他指标有在第7天降低之后又升高的趋势,这意味着肝细胞DNA损伤可在一定程度上反映水体中BaP的污染情况。该实验为进一步探讨苯并（a）芘的致癌机制及环境中苯并（a）芘的监测提供一定的科学依据。     

青春期双酚A结构类似物暴露对小鼠行为的影响

作为重要的环境内分泌干扰物,双酚A的神经发育毒性已经引起广泛关注,其结构类似物对健康影响相关研究少有报道。为探讨双酚A结构类似物长期暴露对个体抑郁行为的影响,选取60只小鼠随机分为5组,每组12只。小鼠分别灌胃给予0、5、50 mg·kg~(-1)的双酚F或双酚S,连续给药4周。给药结束后,利用强迫游泳测试和悬尾测试评价小鼠抑郁样行为,同时监测小鼠体质量增加和自发活动情况。结果表明,与溶媒对照组比较,持续4周的双酚F和双酚S给药组小鼠的体质量变化和自发活动均无显著差异;5mg·kg~(-1)的双酚F或双酚S处理均不显著改变小鼠的抑郁行为,50 mg·kg~(-1)双酚F显著增加小鼠悬尾和强迫游泳测试中的不动时间,50mg·kg~(-1)双酚S处理显著增加小鼠悬尾测试中的不动时间。研究结果提示高浓度双酚F和双酚S在青春期的暴露可导致成年后小鼠抑郁样行为异常,应当引起重视。     

苯并[a]芘对马氏珠母贝血淋巴细胞DNA损伤的研究

通过单细胞凝胶电泳技术(彗星试验)研究了苯并[a]芘(B[a]P)对马氏珠母贝(Pinctada martensi)血淋巴细胞DNA的损伤。结果显示,在相同暴露时间内,不同质量浓度的B[a]P均能引起马氏珠母贝血淋巴细胞DNA损伤。4μg.L-1 B[a]P处理组DNA含量、彗尾长度和Olive尾矩均最大,分别为34.39%、281.73和60.31μm。随着暴露时间的延长,彗星尾长明显增加,表现出明显的时间-效应关系,而DNA含量和Olive尾矩没有呈现出规律性变化。此外,在不同的染毒时间内,对照组和各处理组之间均存在显著差异(P<0.05),3个指标具有很好的一致性。研究表明,彗星试验是检测B[a]P对马氏珠母贝血淋巴细胞DNA损伤的一种有效手段,马氏珠母贝血淋巴细胞DNA损伤可作为指示B[a]P污染的一种有效生物标志物用于早期预警监测。     

苯并[a]芘对马氏珠母贝血淋巴细胞DNA损伤的研究

通过单细胞凝胶电泳技术（彗星试验）研究了苯并[a]芘（B[a]P）对马氏珠母贝（Pinctada martensi）血淋巴细胞DNA的损伤。结果显示,在相同暴露时间内,不同质量浓度的B[a]P均能引起马氏珠母贝血淋巴细胞DNA损伤。4μg.L-1 B[a]P处理组DNA含量、彗尾长度和Olive尾矩均最大,分别为34.39%、281.73和60.31μm。随着暴露时间的延长,彗星尾长明显增加,表现出明显的时间-效应关系,而DNA含量和Olive尾矩没有呈现出规律性变化。此外,在不同的染毒时间内,对照组和各处理组之间均存在显著差异（P〈0.05）,3个指标具有很好的一致性。研究表明,彗星试验是检测B[a]P对马氏珠母贝血淋巴细胞DNA损伤的一种有效手段,马氏珠母贝血淋巴细胞DNA损伤可作为指示B[a]P污染的一种有效生物标志物用于早期预警监测。     

全氟辛烷磺酸(PFOS)和多壁碳纳米管(MWCNTs)复合对斑马鱼外周血红细胞DNA的损伤

为了评价全氟辛烷磺酸(PFOS)和多壁碳纳米管(MWCNTs)对水环境及鱼类的影响,以斑马鱼为模式生物,研究了PFOS和MWCNTs复合对斑马鱼外周血红细胞的DNA损伤。将成年斑马鱼暴露于PFOS(0.2、0.4、0.8、1.6 mg·L-1)、MWCNTs(50 mg·L-1)、PFOS+MWCNTs(0.2+50、0.4+50、0.8+50、1.6+50 mg·L-1)和对照溶液中30 d后,断尾取血进行微核试验和彗星试验。结果表明:PFOS和MWCNTs均可造成斑马鱼外周血红细胞的DNA损伤。1.6 mg·L-1PFOS处理组的微核率、Olive尾矩及尾长分别为(36.3±0.25)‰、(87.91±14.90)μm和(250.49±34.71)μm。PFOS与MWCNTs复合后,斑马鱼外周血红细胞的DNA损伤效应明显降低。复合处理组斑马鱼外周血红细胞的微核率、Olive尾矩及尾长均低于PFOS单独处理相。1.6 mg·L-1复合处理组的微核率、Olive尾矩及尾长比PFOS单独处理组分别降低了24.7%、68.9%、52.4%。因此,在实验浓度范围内,MWCNTs可以降低PFOS对斑马鱼外周血红细胞的DNA损伤。     

铀胁迫对大豆与玉米幼苗细胞DNA损伤的彗星试验研究

以铀浓度为1000 μmol·L-1、800 μmol·L-1、600 μmol·L-1、400 μmol·L-1、200μmol·L-1和100μmol·L-1的6组铀溶液和对照组(0μmol·L-1)培养大豆和玉米幼苗,采用彗星试验研究铀胁迫对大豆和玉米幼苗细胞DNA的损伤情况.试验结果表明,铀浓度为1 000 μ...     

邻苯二甲酸二乙基己酯（DEHP）对金鲫鱼脑细胞DNA的损伤

为了研究邻苯二甲酸二乙基己酯(DEHP)对金鲫鱼(Carassius auratu)脑细胞DNA的损伤作用,采用不同浓度的DEHP溶液(0、25、50、100、200mg·L-1)对体外培养脑细胞进行染毒,应用单细胞凝胶电泳(彗星实验)检测脑细胞DNA的损伤效应.结果表明,染毒1.5h后,与对照组相比,DEHP各染毒组细胞尾部DNA百分率(Tail DNA%)和尾矩(Tail Moment)均显著升高(p<0.01),即DEHP染毒引起了脑细胞DNA的严重断裂;随着DEHP浓度的增加,DNA损伤程度加剧,细胞尾部DNA百分率及尾距与DEHP染毒浓度呈明显的剂量-效应关系.以上结果表明,DEHP可导致金鲫鱼脑细胞DNA损伤。     

吡啶硫酮金属对华美盘管虫(Hydroides elegans)精子DNA的损伤效应

吡啶硫酮铜(Cu PT)和吡啶硫酮锌(Zn PT)在渗出型海洋防污涂料中的应用日益广泛,其生态毒性引起了人们的关注。本文以南海海域常见优势种——华美盘管虫(Hydroides elegans Haswell)为试验动物,采用彗星实验研究了吡啶硫酮金属对华美盘管虫精子细胞DNA的损伤情况。结果显示,低浓度(4μg·L~(-1)Cu PT或8μg·L~(-1)Zn PT)处理组的精子细胞,其"彗星"尾长、尾DNA含量及Olive尾矩都显著高于溶剂对照组(P0.05);较高浓度(8μg·L~(-1)或16μg·L~(-1)Cu PT,16μg·L~(-1)或32μg·L~(-1)Zn PT)处理组的精子细胞,其"彗星"尾长和尾矩多数显著高于溶剂对照组(P0.01)。此外,尾长和Olive尾矩在试验浓度范围内都呈现"效应-浓度"正相关。Cu PT为4μg·L~(-1)、Zn PT为8μg·L~(-1)时,对精子DNA造成轻度损伤;Cu PT为8μg·L~(-1)、16μg·L~(-1),Zn PT为16μg·L~(-1)、32μg·L~(-1)时,则达到了中度损伤的程度。可见吡啶硫酮金属具有较明显的海洋生态遗传毒性;另一方面,华美盘管虫精子细胞DNA对吡啶硫酮金属的胁迫呈现出较高的敏感性和效应-浓度相关性,在作为生态遗传毒性的生物指标方面具有潜在优势,进一步的研究将促进其在海洋重金属污染评价中的应用,特别是用于南海海洋环境的早期预警监测。     

利用彗星试验研究菲对蚕豆DNA的损伤

以蚕豆(Vicia faba)为对象、以菲为多环芳烃(PAHs)代表物开展彗星试验,用Komet Version 6.0软件进行彗星图像分析,并选择评价参数研究PAHs污染的DNA损伤效应。以Olive尾动量(OTM)作为DNA损伤的评价参数,细胞彗星试验中蚕豆根尖DNA的损伤程度随菲质量浓度(0~0.6 mg·L-1)升高而显著增大。最高浓度组(0.6 mg·L-1)OTM值比阴性对照增加132.63%,存在剂量依赖性,表明菲能诱导蚕豆根尖DNA损伤。在培养液中菲质量浓度为0.1 mg·L-1条件下培养蚕豆,0~12 h时DNA损伤程度随时间延长而增大,12 h时OTM值为38.82±4.48;12~24 h时DNA损伤程度则随时间延长而趋小。为确定菲污染导致DNA损伤的途径,进行非细胞彗星试验,结果表明,0.05 mg·L-1菲即可造成显著DNA损伤(OTM值为22.27±0.42),且DNA损伤程度随菲浓度提高而增大。菲对蚕豆根尖细胞可能存在直接的DNA损伤效应。     

苯并[a]芘和菲对缢蛏血细胞DNA损伤的研究

为研究苯并[a]芘和菲对缢蛏的毒性效应,将缢蛏(Sinonovacula constricta)分别暴露于浓度为0.45 mg·L-1、0.15 mg·L-1、0.05 mg·L-1苯并[a]芘溶液和0.45 mg·L-1、0.15 mg·L-1、0.05 mg·L-1菲的溶液中,采用单细胞凝胶电泳实验(彗星实验)技术检测不同暴露时间缢蛏血淋巴细胞的DNA损伤程度,对照组为清洁海水。结果显示,高浓度(0.45 mg·L-1)苯并[a]芘溶液和(0.45 mg·L-1)菲溶液在短期(7 d)内即可导致缢蛏血细胞显著的DNA损伤,并且随苯并芘[a]和菲浓度的增大和暴露时间的延长,DNA损伤程度增加。21 d恢复实验后,各浓度组DNA损伤又均有不同程度的恢复,但中高浓度组(0.45 mg·L-1和0.15 mg·L-1)与对照组仍显著性差异。两种多环芳烃物质对缢蛏血细胞的DNA损伤作用均存在较显著时间-剂量-效应关系。其中,苯并芘[a]对缢蛏血细胞的DNA损伤作用要高于菲。     

Removal of boron by electrocoagulation

Boron compounds are used in many manufacturing products and may be introduced into the environment in the form of hazardous materials. Here the feasibility of removal of boron from aqueous solutions by electrocoagulation was investigated. The process was examined under various factors in order to assess optimal operating conditions. The results showed that electrocoagulation for boron removal depends on current density, initial concentration and time. Under a current density of 30 mA/cm² the percentage of boron removal from aqueous solutions is in the range of 92–96%.     

Products of denitrification by a marine bacterium as revealed by gas chromatography

Gas chromatography was used to analyse the gases released by growing cultures of the denitrifying marine bacterium Pseudomonas perjectomarinus. When nitrate was provided as final oxidant, CO₂ was the first detectable gas released. Following the peak rate of release of CO₂ at approximately 16 h, N₂ liheration began and peaked at 30 h. When N₂O was provided as terminal oxidant, CO₂ and N₂ release began within a few hours and the rate of liberation of both increased for 45 to 50 h before leveling. Cell-free extracts of bacteria from denitrifying cultures of P. perfectomarinus were incubated anaerobically with nitrate, malic acid and electron transfer cofactors provided, and the gases in the atmosphere above the reaction mixtures were analysed. NO was found to be present transiently, and N₂O was discerned after prolonged incubation. The applicability of gas chromatography to analyses of marine ecosystems and the need for better means of sampling the atmosphere above enzymatic reaction mixtures were disoussed.     

Direct measurement of dissolved organic carbon release by phytoplankton and incorporation by microheterotrophs

It is now possible to divide particulate primary production into algal and heterotrophic components without physical separation. This depends on two innovations, the introduction of isotope in the form of labelled dissolved product(s) of primary production and the employment of a data analysis specifically designed for tracer kinetic incorporation experiments. The ¹⁴C technique described by Steemann Nielsen (1952) is inapplicable in the analyses of certain classes of systems and kinetic tracer incorporation experiments must be employed instead. We show that measurement of PDOC production rate requires such kinetic tracer analyses. Measurements made in the laboratory on water taken from 2 m depth in South West Arm of the Port Hacking estuary showed that: (1) the steady-state rate of PDOC production was 0.10 to 0.13 mg C.m^-3.h^-1; (2) the rate of PDOC incorporation into microheterotroph particulate organic carbon was 0.10 to 0.12 mg C.m^-3.h^-1; (3) the rate at which PDOC was respired to CO₂ was 0.001 to 0.003 mg C.m^-3.h^-1. (4) the PDOC makes up only about 0.1% of the total dissolved organic carbon. The size class of particles associated with PDOC production differed from the size class responsible for uptake of PDOC. More than 50% of the PDOC production was associated with particles having a nominal diameter range of 20 to 63 m, while this fraction was responsible for <10% of the incorporation.     

不同阳离子影响下小麦根吸收镉的动力学过程

生物配体模型(BLM)是基于稳定态假设的一个平衡模型,能够较准确地运用于预测重金属的毒性及其生物有效性.根据BLM模型的假设条件模拟土壤溶液,研究了Ca2+、Mg2+、Cu2+和Ni2+对小麦根吸收Cd2+动力学的影响,阐述了BLM在应用中存在的局限性.结果表明:在8h内的短期动力学吸收实验中,小麦根对Cd的吸收及吸附量呈线性增加,但未达到稳定值,这说明Cd2+在根-液界面未达到稳定平衡;并且小麦根对Cd的吸收是受溶液中Cd2+扩散速率影响的.小麦根对Cd的吸收通量与Cd2+浓度[Cd2+]和Cd与小麦根表上的配体结合浓度{Cd-Rcel}l都具有较好的线性关系,但随着Cd2+浓度的增加稳定常数KM-Rcell、渗透常数p和同化速率常数kint均呈降低趋势.Ca2+、Mg2+和Cu2+降低了小麦根对Cd2+的吸收通量,而Ni2+对Cd2+的竞争作用不显著.由于Cd与Ca、Ni有共同的吸收通道,Ca通道吸收达到饱和后可降低小麦根对Cd的吸收,但是Ca2+、Mg2+和Cu2+通过降低内化速率常数也可使小麦根对Cd的内化通量减少,因此不能完全用竞争效应解释其结果.另外,阳离子的存在会改变小麦根表的性质,Ca2+、Mg2+的存在会增加亨利系数KCd,即生物配体浓度{Rcel}l和(或)离子与生物配体结合稳定常数KCd-Rcell会增加,同时这些离子的存在还会降低渗透常数p和kint;Cu2+、Ni2+的存在会降低KCd;且p和k在低浓度Cd(0.01～0.05μM)条件下增加,在高浓度Cd条件下降低.     

Uptake of aluminum by lipid vesicles

Aluminium uptake and tight binding were studied in multilayered phospholipid liposomes, as a model for cellular uptake of aluminum ions. Most of these studies were conducted with an initial aluminum concentration of 10 μM, while aluminum superficially bound to liposomes was removed by citrate chelation. Maximum uptake and tight binding of aluminium were pH‐dependent. In dimyristoyl phosphatidylcholine (DMPC) liposomes, this maximum occurred in the neutral pH region, while it was shifted towards more acidic pH values in DMPC liposomes containing 20% of acidic phosphatidylserine. The initial rate of aluminum uptake was apparently dependent on the physical state of the liposome membrane. Prior formation of an aluminum‐citrate chelate prevented aluminum uptake and tight binding to DMPC liposomes.     

嗜酸氧化亚铁硫杆菌对煤炭脱硫影响的研究

嗜酸氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans)广泛应用于湿法冶金和煤炭脱硫。不同的实验条件对煤炭脱硫效率的影响很大。以QXS菌株为实验对象,分别考查了处理时间、初始pH、煤样粒度、煤浆质量分数等因素对煤炭脱硫效率的影响,结果表明:处理时间达到10d后,全硫脱除率达到65%且不再继续增加;初始pH的影响符合钟罩形曲线,最佳pH条件为2.0左右;伴随煤样粒度和煤浆质量分数的增加,脱硫的效果均呈现减弱趋势。此外,对具有不同Fe2 氧化能力的菌株的脱硫能力进行了对比分析,结果表明它们的脱硫效率与Fe2 氧化能力呈正相关。采用QXS菌株,煤浆质量分数为20%,煤样粒度为200目(<0.074mm),初始pH为2.0,温度30℃,摇床转速为175r/min,接种量为1010～1011·g-1时,10d后煤炭的全硫脱除效率可达65.1%。     

淡紫拟青霉对辛硫磷的降解效应

采用菌、药混合培养的方式研究淡紫拟青霉对降解辛硫磷的降解作用,并探讨不同培养基、不同加药量及继代培养对降解效能的影响.结果表明:菌、药混合培养5d,辛硫磷的降解率可达96%以上.降解率随加药浓度的升高而下降,摇瓶培养液中的加药量达到8000μg/mL时,辛硫磷的降解率明显下降为25.51%.察氏、孟加拉红、PDA培养液降解力最强,在辛硫磷添加量达400μg/mL的摇瓶培养液中,菌、药混合培养5d,降解率可达98%以上.短期内继代培养对淡紫拟青霉菌的降解能力没有明显影响,所有继代培养处理对辛硫磷的校正降解率均在94%左右,且无显著差异.以上结果初步证实,淡紫拟青霉对有机磷农药具有显著的生物降解活性.图2表3参19     

Fenton法降解水中布洛芬

采用Fenton法降解水中布洛芬,考察了H2O2投加量、FeSO.47H2O与H2O2的比值、初始pH、反应时间等因素对布洛芬去除率的影响,通过正交实验确定影响作用大小依次为:[Fe2+]∶[H2O2]的物质的量之比>H2O2的投加量>pH值,最佳的反应工艺条件为:H2O2的投加量为3 mL.L-1,[Fe2+]∶[H2O2]的物质的量之比为1∶10,反应初始pH值为3,反应时间为40 min.在最佳条件下布洛芬的去除率达到86%以上.同时对布洛芬降解反应动力学进行了研究,发现Fenton降解布洛芬符合二级反应动力学规律.     

Rapid degradation of carbon tetrachloride by commercial micro-scale zinc powder assisted by citric acid

We developed an effective method for degradation of carbon tetrachloride (CT) in contaminated water. Zinc metal as a reducing agent for CT in aqueous solutions has been previously studied in some detail, but the rapid corrosion of zinc surface usually reduces its efficiency in removing CT. We assumed that citric acid could enhance the degradation of CT by zinc powder due to the elimination of a passivation layer of Zn(II) (hydr)oxides on the surface of zinc powder through chelating of organic ligands with Zn(II) produced from the reaction and keeping the exposure of active sites to targets. Here the influence of citric acid on the decomposing of CT by commercial micro-scale zinc powder was investigated in a pH range of 3.5–7.5 at 25°C in batch experiments. Reaction mixtures were analysed by gas chromatography/headspace analysis, and Cl⁻ concentration was determined by turbidimetry. The results demonstrate that the degradation of CT by zinc metal alone is very weak, but the addition of citric acid can assist zinc powder to decompose CT more completely and rapidly at all pHs. Degradation of CT took place mainly in the first 10 min of reaction, coupled with 75–95% of CT removal. Maximum dechlorination percentage (82.4%) of CT was obtained at pH 5.5. In that case, chloroform and dichloromethane, as main intermediates, were found at low levels during the whole reaction, suggesting that CT may be sequentially and multiply degraded so quickly that methane is yielded before the intermediates can be desorbed and released to aqueous solution. When compared with the current methods of nano-scale zinc and bimetallic systems, the application of commercial micro-scale zinc particles assisted by organic ligands is of environmental significance since it allows decontamination of aqueous chlorinated organic compounds at low cost and with high efficiency.