有机磷农药和重金属对海洋微藻的联合毒性研究

以三角褐指藻、盐藻和青岛大扁藻为实验材料，采用联合指数相加法，研究了有机磷农药和重金属对这三种海洋微藻的急性毒性和联合毒性效应。实验结果表明，铜对这三种微藻毒性顺序为： 青岛大扁藻＞ 三角褐指藻＞ 盐藻。丙溴磷农药对三种微藻毒性顺序为： 三角褐指藻＞ 青岛大扁藻＞ 盐藻。盐藻对两种污染物均表现出较强耐受性。联合毒性实验结果显示： 对于三角褐指藻、盐藻和青岛大扁藻，丙溴磷－ 铜联合毒性在毒性比１∶１ 情况下，７２ ｈ Ａ Ｉ分别为－ ０４６２ 、－ ０５５７ 和－ ０７０２ ，均为拮抗作用     

杀螟松、马拉松、杀扑磷和杀灭磷在不同pH和温度下的水解速率

水解是农药在环境中降解的一条重要途径。为正确评价农药在各种环境条件下的残留行为,有必要系统地研究温度和介质酸碱度对农药水解速率的影响。     

Rhodococcus sp.BX2菌对乙腈的降解特性及降解途径研究

对Rhodococcus sp.BX2菌降解乙腈的特性及其降解途径进行了研究.结果显示,在底物浓度为800mg·L-1,接种量为1.0%,培养温度为35℃,环境pH为7.5的条件下,16h时Rhodococcus sp.BX2菌对乙腈的降解率为95.98%;添加葡萄糖可在培养初期加快Rhodococcus sp.BX2菌的生长和对乙腈的降解,蔗糖、乙酰胺和尿素对其影响不大.将BX2菌接种到含有高乙腈浓度(25000mg·L-1)的合成废水中,培养180h后,乙腈降解率可达88.59%.在催化反应60min后,Rhodococcus sp.BX2腈水合酶与腈水解酶的总酶活可达到422.81U·mL-1,对其相关基因序列的分析结果表明,Rhodococcus sp.BX2中同时存在腈水解酶基因和腈水合酶基因,因此,确定乙腈的降解主要由腈水合酶途径完成,可能同时存在腈水解酶的降解途径.     

有机磷农药的构效关系及其对浮游生物的毒性效应

以定量构效关系理论和实验室内急性毒性试验相结合研究了六种有机磷农药对四尾栅藻（S.quadricanda）和多刺裸腹溞（Moina macrocopa）的生态毒性。有机磷农药的毒性取决于磷原子的电正性,各取代基种类和构象对电荷分布作用显著。根据构效关系原理,磷氧双键（P=O）被磷硫双键（P=S）取代后毒性降低;羟基（-OH）被甲、乙、丙氧基（-CH3O、-CH3CH2O、-CH3CH2CH2O）取代后有机磷农药毒性依次增强;磷氧单键（P-O）毒性高于磷碳单键（P-C）。该实验中毒死蜱、辛硫磷（-CH3CH2O）毒性高于其它四种（-CH3O）,敌敌畏和敌百虫（P=O）毒性高于乐果（P=S）,敌敌畏（P-O）又高于敌百虫（P-C）,甘氨酸异丙胺盐取代羟基（-OH）的草甘膦毒性最低。毒性试验结果表明,毒死蜱、辛硫磷、敌百虫、敌敌畏、乐果、草甘膦异丙胺盐对四尾栅藻的96 h EC50分别为6.34、6.62、59.53、82.12、141.37和7.25 mg.L-1。它们对多刺裸腹溞的48 h LC50分别为0.20、0.12、0.28、0.17、1.12和5.03 mg.L-1。六种有机磷农药对多刺裸腹溞的毒性强度结果与QSAR分析具有较高的一致性,即表征有机磷农药毒性特征的取代基团作用的毒性强弱顺序为：-OH〉=O〉-O;对四尾栅藻毒性试验结果中,由于草甘膦异丙胺盐作用于植物类靶位点的特殊性,导致其对四尾栅藻毒性显著增强。综合以上研究,以构效关系理论和浮游生物毒性试验相结合进行有机磷农药的生态风险评价将更加便捷和准确。     

Ecotoxicological effect of zinc oxide nanoparticles on soil microorganisms

The widespread production and use of zinc oxide nanoparticles (ZnO-NPs) in recent years have posed potential threat to the ecosystem. This study aimed to investigate the ecotoxicological effect of ZnO-NPs on soil microorganisms using laboratory microcosm test. Respiration, ammonification, dehydrogenase (DH) activity, and fluorescent diacetate hydrolase (FDAH) activity were used as ecotoxicological parameters. The results showed that in the neutral soil treated with 1 mg ZnO-NPs per g soil (fresh, neutral), ammonification was significantly inhibited during the study period of three months, but the inhibition rate decreased over increasing time. Inhibition in respiration was observed in the first month of the test. In various ZnO-NPs treatments (1 mg, 5 mg, and 10 mg ZnO-NPs per g soil), DH activity and FDAH activity were inhibited during the study period of one month. For both enzyme activities, there were positive dose–response relationships between the concentration of ZnO-NPs and the inhibition rates, but the curves changed over time due to changes of ZnO-NPs toxicity. Soil type affected the toxicity of ZnO-NPs in soil. The toxicity was highest in the acid soil, followed by the neutral soil. The toxicity was relatively low in the alkaline soil. The toxicity was not accounted for by the Zn²⁺ released from the ZnO-NPs. Direct interaction of ZnO-NPs with biologic targets might be one of the reasons. The adverse effect of ZnO-NPs on soil microorganisms in neutral and acid soils is worthy of attention.     

信息理论指数及其在有机磷农药毒性预测研究中的应用

为探讨化合物结构与毒性关系研究方法,将定量描述分子结构特征的信息理论指数、价分子连续性指数应用于有机磷农药毒性预测研究,提出了基团信息参数。运用判别分析、多元非线性回归分析,依据１１４种有机磷农药急性毒性数据资料,按动物不同给药途径,分别建立定性、定量预测模型,定性判别回代符合率均在８３．３３％以上,定量回归方程相关指数Ｒ＾２均在０．８１以上,回归残差呈正态分布。预测分析,预测值均在ＬＤ５０测定值     

三种有机磷萃取剂对水生生物的毒性效应

通过３种有机磷萃取剂：甲基磷酸二仲辛酯（P350）、异辛基磷酸单异辛酯（P507）和磷酸二异辛酸（P204）对不同营养级水平的单种生物：藻类（斜生棚藻）、草履虫（尾草履虫）、类（大型）、鱼类（鱼苗）的毒性试验,结果表明：３种有机磷萃取剂的毒性效应浓度（半致死浓度或半抑制浓度）为P350：0.40～9.30mg/L,P507：23.32～112.00mg/L,P204：59.50～138.00mg/L;毒性强弱的顺序为P350＞P507＞P204;建议把P350、P507、P204在水体中的安全浓度暂分别定为0.04mg/L、2.33mg/L和4.71mg/L。     

北方某城市饮用水处理中卤乙酸浓度水平的调查研究

利用SPEGCFPD对厦门附近海域的微表层、表层、底层海水及九龙江入海口高、低潮水中有机磷农药进行了分析.结果表明,有机磷农药的含量范围为:低于检测限～725.54ng·L-1,平均值为136.47ng·L-1.研究海区中马銮内湾有机磷农药污染最为严重(165.77～453.42ng·L-1,平均296.01ng·L-1),九龙江口、西海域和西南海域污染水平接近(16.26～200.65ng·L-1,平均84.59ng·L-1),东部海域有机磷农药污染最轻(10.38～66.01ng·L-1,平均38.14ng·L-1).九龙江入海口高潮水中农药的浓度明显低于低潮水中浓度,说明海域中多数农药污染来源于九龙江流域输入,少数农药来源于海域周边地区或九龙江流域和海域周边地区共同输入,微表层对有机磷农药的富集作用不明显.     

Effect of organic/inorganic compounds on the enzymes in soil under acid rain stress

IntroductionEnzymeexistsextensivelyinsoil.Itnotonlycanactivatecomplexorganiccompoundchangeintosimpleinorganiccompoundtosupplytheplants(Srivastava ,1991;Hojeong ,1999)butisalsooneofthesoilcapacityindexesaswell(Yu ,1998;Irvinc ,1993;Zeng ,2 0 0 1) .Theactivityofsoilenzymeiseasilyinfluencedbyphysical,chemicalandbiogenicfactorsinenvironment.Whentheenvironmentispolluted,enzymeactivitieschangesignificantly .Theuseofenzymeactivitiesasbioindicatorstoevaluatethedegreeofsoilcontaminationbyheavymetals…     

An alkaline phosphatase from Bacillus amyloliquefaciens YP6 of new application in biodegradation of five broad-spectrum organophosphorus pesticides

In recent decades, biodegradation has been considered a promising and eco-friendly way to eliminate organophosphorus pesticides (OPs) from the environment. To enrich current biodegrading-enzyme resources, an alkaline phosphatase (AP3) from Bacillus amyloliquefaciens YP6 was characterized and utilized to test the potential for new applications in the biodegradation of five broad-spectrum OPs. Characterization of AP3 demonstrated that activity was optimal at 40?°C and pH 10.3. The activity of AP3 was enhanced by Mg²⁺, Ca²⁺, and Cu²⁺, and strongly inhibited by Mn²⁺, EDTA, and L-Cys. Compared to disodium phenyl phosphate, p-nitrophenyl phosphate (pNPP) was more suitable to AP3, and the V_m, K_m, k_cat, k_cat/K_m values of AP3 for pNPP were 4,033?U mg^?1, 12.2?mmol L^?1, 3.3?×?10⁶ s^?1, and 2.7?×?10⁸ s^?1mol^?1L, respectively. Degradation of the five OPs, which included chlorpyrifos, dichlorvos, dipterex, phoxim, and triazophos, was 18.7%, 53.0%, 5.5%, 68.3%, and 96.3%, respectively, after treatment with AP3 for 1?h. After treatment of the OP for 8?h, AP3 activities remained more than 80%, with the exception of phoxim. It can be postulated that AP3 may have a broad OP-degradation ability and could possibly provide excellent potential for biodegradation and bioremediation in polluted ecosystems.