Acute Single and Joint Toxicity Effects of Deltamethrin and Lambda-cyhalothrin on Zebrafish(Danio rerio)

In this research,the single and combined toxicity effects of two commonly used pesticides,lambda-cyhalothrin and deltamethrin,were investigated on zebrafish at 20℃,with a weight of(1±0.1)g and a length of(3.5±0.35)cm.The study revealed that lambda-cyhalothrin exhibited higher toxicity compared to deltamethrin.Additionally,when used together,these pesticides showed significantly increased toxic effects on zebrafish.The 96-h LC 50 values were determined to be 3.059μg/L(confidence limits 0.077-0.351μg/L)for lambda-cyhalothrin and 1.304μg/L(confidence limits;0.046-0.228μg/L)for deltamethrin,both demonstrating a significant positive correlation(P<0.05).These results underscore the importance of regulating and managing pesticide use to safeguard aquatic organisms and uphold environmental sustainability.

Quantitative structure-activity relationships for joint toxicity of substituted phenols and anilines to Scenedesmus obliquus

There are often many chemicals coexisting in aquatic ecosystems, and few information on the joint toxicity of a mixture of organic pollutants is available at present. The 48-h toxicity of substituted phenols and anilines and their binary mixtures to Scenedesmus obliquus was determined by the algae inhibition test. The median effective inhibition concentration EC50 values for single compounds and EC50mix values for coexistent compounds were obtained. The n-octanol/water partition coefficient （logPmlx） and the frontier orbital energy gap （AEmlx） for mixtures were calculated. The following two-descriptor quantitative structure-activity relationships （QSARs） models were developed to predict single toxicity and joint toxicity respectively： log（1/ECs0） = 0.445logP - 0.801AE ＋ 9.501 （r2 = 0.876） and log （1/EC50mix） = 0.338logPmix- 0.492AEmix ＋ 6.928 （r^2 = 0.831）. The two equations were found to fit well. In addition, the model derived from the structural parameters of single components in binary mixtures log（1/EC50mix） = 0.2221ogP - 0.277AE ＋ 5.250 （r^2 = 0.879） can be used successfully to predict the toxicity of a mixture.

Acute and joint toxicity of three agrochemicals to Chinese tiger frog （Hoplobatrachus chinensis） tadpoles

We studied acute and joint toxicity of three different agrochemicals （chlorantraniliprole, flubendiamide-abamectin and penoxsulam） to Chinese tiger frog （Hoplobatrachus chinensis） tadpoles with the method of stability water tests. Results showed that the three agrochemicals increased tadpole mortality. For acute toxicity, the LC50 values after 24, 48 and 72 h of chlorantraniliprole, flubendiamide-abamectin and penoxsulam exposure were 5.37, 4.90 and 4.68 mg/L; 0.035, 0.025 and 0.021 rag/L; 1.74, 1.45 and 1.29 mg/L, respectively. The safety concentrations （SC） of chlorantraniliprole, fiubendiamide-abamectin and penoxsulam to the tadpoles were 1.23, 0.30 and 0.003 mg/L, respectively. Based on these findings, chlorantraniliprole and penoxsulam were moderately toxic, while flubendiamide-abamectin was highly toxic. All pairwise joint toxicity tests showed moderate toxicity. The LCs0 values after 24, 48 and 72 h of exposure were 7.08, 6.61 and 6.03 mg/L for chlorantra- niliprole＋penoxsulam, with corresponding values of 2.455, 2.328 and 2.183 mg/L for chlorantraniliprole＋flubendiamide-abamectin, and 1.132, 1.084 and 1.050 mg/L for penoxsulam＋flubendiamide-abamectin, with safe concentrations of 1.73, 0.63 and 0.30 mg/L, respectively. For toxic evaluations of pairwise combinations of the three agrochemicals, only the joint toxicity of chlorantraniliprole and flubendiamide-abamectin after 24 h was found to be synergistic, whereas all other tests were antagonistic. Our findings provide valuable information on the toxic effects of agrochemicals on amphibians and how various types of agrochemicals can be reasonably used in agricultural areas.

Joint Toxicity of Beauveria bassiana and Two Insect Growth Regulators on Beet Armyworm,Spodoptera exigua(Hübner)

Joint toxicity of Beauveria bassiana and two insect growth regulators, methoxyfenozide and hexaflumuron, on beet annywonn larvae, Spodoptera exigua （ Htthner）, were investigated. An obvious synergism effect of the two insect growth regulators with B. beauveria was observed. When the insect growth regulators at LC50 concentrations （25 × 10^-6 g/L for methoxyfenozide and 1 000 × 10^ -6 g/L for hexaflumuren） were mixed with B. bassiana at the volume ratio of 4： 1, the mixtures achieved the best efficacy. The co-toxicity co-efficient （CTC） of methexyfenozide and B. bass/ana was 285, and that of hexaflumuron and B. bass/ana was 208. Scanning electron microscope observation of the longitudinal section of S. exigua revealed obviously different patterns of integument in different treatment groups.

Joint toxicity of methamidophos and cadmium acting on Abelmoschus manihot

Joint toxicity of methamidophos and cadmium(Cd) on the ornamental Abelmoschus manihot was firstly examined and compared with single-factor effects of the two pollutants using ecotoxicological indexes including the inhibitory rate of seed germination, root elongation and inhibitory concentration 50%(IC_ 50). The results indicated that methamidophos and Cd had unobvious(p>0.05) effects on seed germination of the ornamental. There were significant(p<0.05) inhibitory effects of Cd on root elongation of the tested plant. When the concentration of added Cd was low(<20 mg/L), significant antagonistic effects on root elongation were observed. And synergic effects were observed when Cd was added in high dose(>20 mg/L). However, the analysis of joint effects indicated that there were antagonistic effects between Cd and methamidophos under all the treatments. At the high concentration of Cd, joint toxicity of methamidophos and Cd was more dependent on concentration of Cd.

Evaluation and Prediction of Joint Toxicity of Aniline and Its Derivatives to Photobacterium Phosphoreum

The single toxicity of aniline and its derivatives and the joint toxicity of the binary mixtures of aniline and each of its derivatives with the toxic unit ratios of 1∶1, 1∶4, 4∶1 to photobacterium phosphoreum were determined, respectively. The toxic unit and the additive index were used to evaluate the joint toxicity. The result shows that the joint toxicity of each of the binary mixtures of aniline and each of its derivatives is mainly simple addition of the toxicities of the two compounds. On this basis, the QSAR equation that was built from the single toxicity of aniline was used to predict the toxicity of the derivatives of aniline in the mixtures. Good agreement between the predicted and experimental values was found with R 2=0.921.

Joint Toxicity Determination of Clopyralid,Picloram and Benazolin Mixtures on Broad-leaved Weed Lapsana apogonoides Maxim.in Rape Fields

[Objectives]This study was conducted to investigate the compounding of three herbicides:clopyralid,picloram and benazolin,so as to improve the effectiveness of herbicides.[Methods]With Lapsana apogonoides Maxim.as the target and clopyralid,picloram and benazolin as the test agents,seven gradient concentrations were set up to determine the joint toxicity of the three agents.[Results]When the compounding ratio of picloram,clopyralid and benazolin was 2∶1∶6,the maximum co-toxicity coefficient was 290.0.[Conclusions]The compounding of picloram,clopyralid and benazolin has a significant synergistic effect on L.apogonoides,which reduces production costs and environmental pressure,providing technical support for the effective control of broad-leaved weeds such as L.apogonoides.

Joint toxic effects of heavy metals and atrazine on invasive plant species Solidago Canadensis L.

In this study, the joint effects of Cd(Ⅱ), Pb(Ⅱ) and atrazine (ATR) on Solidago Canadensis L. were investigated. The results showed that soil containing Cd, Pb and ATR could inhibit root elongation of Solidago Canadensis L., and that there was a positive linear relationship between the inhibitory rate of root elongation and the concentrations of Pb(Ⅱ). The mixture of Cd(Ⅱ) and Pb(Ⅱ)-ATR in soil showed a significant adverse effect on root and shoot biomass of Solidago Canadensis L. Acetylsalicylic acid (ASA) contents increased slightly at the lower concentrations of Cd(Ⅱ)-ATR, then decreased when Cd(Ⅱ)-ATR concentrations were higher than those of 1.0 TUmix(Cd+ATR). The toxic effect of Pb(Ⅱ)-ATR on the ASA contents of Solidago Canadensis L. was greater than that of Cd(Ⅱ)-ATR. Soluble sugar contents firstly decreased and then increased with increasing concentrations of Cd(Ⅱ)-ATR and displayed fluctuation with increasing concentrations of Pb(Ⅱ)-ATR. Total protein contents in-creased with increasing concentrations of Cd(Ⅱ) and Pb(Ⅱ)-ATR , relative to the control sample. The NP-SH con-tents showed a significant increase up to 12.2 mg/gfw of Cd(Ⅱ)-ATR, followed by a significant decline to 4.5 mg/gfw after 14 days of exposure. The effect of Pb(Ⅱ)-ATR was similar to that of Cd(Ⅱ)-ATR but the amount of NP-SH was not higher than that of Cd(Ⅱ)-ATR.

Toxic Effects of Cd^(2+),Pb^(2+) and Hg^(2+) on Colpoda inflata

The toxic effects of heavy metal ions, Hg2＋, Pb2＋ and Cd2＋ on Colpoda inflata were studied, finding that the growth of C. inflata had been inhibited signifi- cantly under different concentrations of heavy metal ions. The acute toxicities of Cd2＋, Pb2＋ and Hg2＋ to C. inflata went in the order of Hg2＋, Pb2＋, Cd2＋. The results of joint toxicity showed that the types and magnitudes of joint actions were different at different solution compositions. The joint toxicity of Cd2＋ and Pb2＋ at the concentration proportion of 1：1 and toxic proportion of 1：1 were all antagonism. At the concentration proportion of 1：1, the joint toxicity of Pb2＋ and Hg2＋ was synergistic, and it changed from antagonism to synergistic at the toxic proportion of 1：1. The joint toxicily of Hg2. and Cd2＋ at the concentration proportion of 1：1 was synergistic, and it was antagonist at toxic proportion of 1：1. At the concentration proportion of 1：1：1, the joint toxicity of Cd2＋, Pb2. and Hg2＋ was synergistic, and it changed from antago- nism to synergistic under toxicity proportion of 1：1：1.

Polystyrene nanoplastics aggravated ecotoxicological effects of polychlorinated biphenyls in on zebrafish(Danio rerio)embryos

In view of the accumulation of nanoplastics(NPs)in the food chain of environment and animals,and the good adsorption properties of nano-plastics to toxic substances,it is necessary to explore the influence of NPs in living organisms.In this study,single and joint toxicological effects of polystyrene nanoplastics(PS-NPs,size 80 nm)and polychlorinated biphenyls(PCBs),were explored in freshwater aquatic animal model zebrafish(Danio rerio).Our study found that exposure to single PS-NPs induced mild acute toxicity,albeit the combined exposure of PS-NPs and polychlorinated biphenyls aggravated the toxicity of PCBs in a dose-dependent manner.Results from gene expression profiling showed that NPs exposure could activate detoxification process,resulting in a slight up-regulation of antioxidant genes(sod1,gstp1),bone development genes(bmp2,bmp4)and cardiac gene(tbx20);while PCBs suppressed the detoxification through down-regulation of these genes,and the addition of NPs will exacerbate the impact of PCBs on gene suppression.Importantly,the results of in vivo purification experiments found that NPs showed prolonged retention in liver,intestine and gills of zebrafish and they might have crossed biological barrier and accumulate in lipid-rich tissues and excretion does not appear as the significant pathway for their elimination.In conclusion,the toxic effects of polychlorinated biphenyls on chorionic protected embryos were not significant as zebrafish chorion plays an important role in resisting the invasion of pollutants;PCBs can seriously damage the bone and heart development of zebrafish,while the presence of NPs significantly enhanced the toxicity of PCBs in zebrafish,which is an alarming concern for growing NPs levels and ecological safety in aquatic environment.

Studies on acute toxicity of three heavy metal ions to Artemia

Studies on acute toxicity of Cu2+,Mn2+and Zn2^to Artemianauplii(36h)and adults were carried out at15±3°C in the natural seawater where salinity is30using single-factor acute toxicity;on this basis,equi-toxicity test was used to evaluate the effect of joint toxicity of Cu2+,Mn2+and Zn2+to Artemia nauplii(36h)in the same conditions.Results show that Artemia has different tolerances for the three heavy metal ions when it is in different growth period,and the interaction of heavy metal ions varied with growth period,adults are more sensitive of the three heavy metals;The48h LC50of these three heavy metal to the Artemia nauplii is4.0,27.19and115.95mg/L,and to the adults is1.31,6.86and34.23mg/L;the order of toxicity of cuprum,manganese and zinc for Artemia nauplii and adults was Cu2^>Mn2+>Zn2+;the safe concentration of the three heavy metal ions(Cu2+,Mn2+and Zn2+)to Artemia nauplii(36h)and adults were0.4,2.72,11.6,0.13,0.69and3.42mg/L.The results of combined toxicity test showed that Cu-Mn,Cu-Zn and Mn-Zn were all antagonistic to the Artemia naupli.

不同药剂对高粱炭疽病菌的室内毒力与复配增效研究

【目的】探明对高粱炭疽病菌具有良好抑制作用的杀菌剂及增效作用明显的复配药剂组合,为高粱炭疽病的田间防治提供科学依据。【方法】采用菌丝生长速率法测定戊唑醇、咪鲜胺、吡唑醚菌酯、肟菌酯、异菌脲和噻呋酰胺6种药剂在不同浓度下对高粱炭疽病菌的抑制率及EC_(50);根据测定结果,选取活性较高的2种药剂按不同比例复配,测定复配剂对高粱炭疽病菌的抑制率、EC_(50)、共毒系数(CTC)及联合毒力,以评价其增效作用,确定最佳复配比例。【结果】6种供试药剂对高粱炭疽病菌均有不同程度的抑制作用,其中,97%咪鲜胺TC的毒力最强,EC_(50)为0.0021 mg/L;98%吡唑醚菌酯TC次之,EC_(50)为0.6103 mg/L。97%咪酰胺TC与98%吡唑醚菌酯TC复配比例为9︰1时,抑制效果最佳,EC_(50)为0.0015 mg/L,CTC为155.49;复配比例为1︰3时,增效作用最佳,EC_(50)为0.0036 mg/L,CTC为230.95。【结论】97%咪酰胺TC与98%吡唑醚菌酯TC复配比例为1︰3的增效作用最佳,具有良好的抑菌活性,可推广应用于田间防控高粱炭疽病。

基于MDR模型的喹诺酮类抗生素对蛋白核小球藻联合毒性作用评估

为考察新污染物中喹诺酮类抗生素混合物的联合毒性效应,以常见的氧氟沙星(Ofloxacin,OFXL)、环丙沙星(Ciprofloxacin,CIP)、诺氟沙星(Norfloxacin,NFXL)3种喹诺酮类抗生素为供试品,通过96 h急性毒性试验测定3种抗生素对蛋白核小球藻(Chlorella pyrenoidosa)生长抑制的单一毒性及二元和三元混合体系(共计20组)的联合毒性,通过等效线图法、浓度加和模型(CA)、独立作用模型(IA)、模型偏移率(MDR)和组合指数法评价二元和三元混合体系抗生素的相互作用类型。结果表明:①3种喹诺酮类抗生素对蛋白核小球藻在96 h均呈现明显的生长抑制,以半数效应浓度EC_(50)的负对数(pEC_(50))作为判断毒性大小的指标,毒性呈NFXL(pEC_(50)=-2.02)>CIP(pEC_(50)=-2.12)>OFXL(pEC_(50)=-2.23)的特征。②混合体系毒性相互作用类型以协同作用为主,毒性相互作用类型与混合体系组分浓度比、毒性效应区域和污染物浓度范围有关。混合体系中混合物组分浓度比最接近1∶1时,协同作用最强,毒性最大。③混合体系在低浓度范围(0%~30%)时,毒性相互作用类型以加和作用为主;在中高浓度范围(30%~100%)时,毒性相互作用随混合体系的不同而呈现出不同类型。研究显示,环境水体中喹诺酮类抗生素对蛋白核小球藻有一定的毒性效应,且抗生素二元、三元混合体系的协同毒性效应呈毒性增大的趋势。

红绶曲霉ACB1042与四种酰胺类杀虫剂的相容性及其对亚洲玉米螟的室内联合毒力

【目的】明确红绶曲霉Aspergillus nomius ACB1042与4种酰胺类杀虫剂的相容性及混配后对亚洲玉米螟Ostrinia furnacalis的毒力。【方法】以4种酰胺类杀虫剂20%氯虫苯甲酰胺SC(悬浮剂)、10%溴氰虫酰胺OF(油悬剂)、10%四氯虫酰胺SC和20%四唑虫酰胺SC的田间推荐浓度为初始浓度,采用血球计数法和十字交叉法分别测定这4种杀虫剂对红绶曲霉ACB1042孢子萌发抑制率、菌丝生长抑制率和产孢抑制率的影响;通过喷雾法测定红绶曲霉ACB1042和20%四唑虫酰胺SC对亚洲玉米螟3龄幼虫的致死中浓度(median lethal concentration,LC_(50))值以及LC_(50)的红绶曲霉ACB1042与LC_(50)的20%四唑虫酰胺SC以体积比9∶1,4∶1,1∶1,1∶4,1∶9混配处理对亚洲玉米螟3龄幼虫的室内联合毒力,测定LC_(50)的20%四唑虫酰胺SC与LC_(50)的红绶曲霉ACB1042以体积比4∶1混剂处理玉米螟3龄幼虫后于24,48,72,96和120 h体内过氧化物酶(peroxidase,POD)、超氧化物歧化酶(superoxide dismutase,SOD)、过氧化氢酶(catalase,CAT)以及多酚氧化酶(polyphenol oxidase,PPO)、羧酸酯酶(carboxylesterase,CarE)和谷胱甘肽S-转移酶(glutathione S-transferase,GST)活性。【结果】4种杀虫剂在田间推荐浓度下对红绶曲霉ACB1042的孢子萌发率、菌丝生长速率和产孢量均有一定的抑制作用,随着杀虫剂稀释倍数增加,抑制作用减弱,其中20%四唑虫酰胺SC 10倍稀释浓度(0.1 RC)与红绶曲霉ACB1042具有较好的相容性:红绶曲霉ACB1042孢子萌发抑制率、产孢抑制率和9 d菌丝生长抑制率依次为0,2.15%和0.78%。红绶曲霉ACB1042与20%四唑虫酰胺SC以不同体积比混配后的共毒系数(co-toxicity coefficient,CTC)均大于120,其中20%四唑虫酰胺SC与红绶曲霉ACB1042以体积比4∶1混用后协同增效作用最好,对亚洲玉米螟3龄幼虫的LC_(50)值为2.359 mg/L,CTC高达365;红绶曲霉ACB1042与20%四唑虫酰胺SC混剂处理后亚洲玉米螟3龄幼虫体内POD,SOD,CAT,PPO,CarE和GST活性随着处理时间推移均呈先上升后下降的趋势。【结论】在田间防治亚洲玉米螟时,可利用红绶曲霉ACB1042与低浓度的20%四唑虫酰胺SC混配,从而达到增效作用。

砷和全氟辛酸对赤子爱胜蚓的联合毒性效应

将赤子爱胜蚓(Eisenia fetida)暴露于亚致死剂量的砷酸盐(As(V))与全氟辛酸(PFOA)的单一及复合污染土壤中28d,分析2种毒物的生物积累和蚯蚓体内多种生物标志物的响应特征,以评估As(V)和PFOA的联合毒性效应.生物富集分析结果表明,土壤中As(V)和PFOA的共存可以增加砷的生物积累量,同时减少PFOA的生物积累.随着暴露水平的增加,大多数生物标志物都表现出显著变化,表明蚯蚓生长受到抑制,并产生了氧化损伤.采用综合生物标志物响应指数(IBR)来整合多种生物标志物响应,发现在As(V)与PFOA的单一及复合污染组中均存在显著的剂量-效应关系.之后,结合IBR和两种复合毒性指数,包括效应加和指数(EAI)和浓度加和指数(CAI),以评估As(V)与PFOA之间的毒性相互作用.结果表明,As(V)和PFOA的联合毒性效应取决于As(V)的暴露浓度,As(V)浓度较高时,复合污染在整个效应水平范围内表现为协同作用,而As(V)浓度较低时的复合毒性则随着效应水平的增加表现出从拮抗作用到协同作用的变化特征.As(V)是对蚯蚓生物标志物造成毒性影响的主要污染物,并影响了As(V)与PFOA的联合毒性效应.本文结果为As(V)和PFOA联合毒性的风险评估提供了有价值的信息.

铜、锌和铅对大型溞的联合毒性效应

以大型溞为试验对象,探究了铜、锌、铅三种重金属单一作用和两两联合作用对大型溞的毒性效应。结果表明:在铜、锌、铅单独作用下,大型溞的96 h半致死质量浓度分别是0.0576、0.3459和13.8100 mg/L;大型溞的安全质量浓度分别是0.0006、0.0035和0.1381 mg/L。这三种重金属作用于大型溞的毒性大小为:铜>锌>铅。通过非线性联合评价方法,分别测定出三种重金属两两联合(Cu+Zn、Cu+Pb、Zn+Pb)作用下大型溞48 h实际致死率均高于理论致死率,表明这三种重金属两两联合对大型溞的毒性效应表现为协同作用。

噻呋酰胺与吡唑醚菌酯复配对烟草靶斑病菌的抑制活性及对烟草靶斑病的室内防效

由立枯丝核菌Rhizoctonia solani引起的靶斑病是近年来烟草主要叶部病害之一,严重降低了烟叶的产量和品质。目前生产中登记用于防治烟草靶斑病的药剂仅有井冈霉素,且该药剂对病害的田间治疗效果较差。为筛选对烟草靶斑病具有优良防效的化学药剂,本研究采用菌丝生长速率法建立了立枯丝核菌对噻呋酰胺和吡唑醚菌酯的敏感性基线,发现两者对立枯丝核菌菌丝生长均有较强的抑制作用。通过联合毒力测定发现两者复配后均表现为相加或增效作用,其中,噻呋酰胺与吡唑醚菌酯按质量比1:1复配,增效作用最明显,增效系数达2.5以上,可显著抑制病原菌菌核形成。采用喷雾接种法测定了该复配比作为保护剂和治疗剂使用时对烟草靶斑病的防效,发现其具有优异的室内防效。本研究结果表明,噻呋酰胺与吡唑醚菌酯按质量比1:1复配在田间防治烟草靶斑病中具有较好的应用前景。

长治市番茄早疫病病原菌鉴定及防治药剂筛选

为明确山西省长治地区番茄早疫病病原菌种类,验证不同化学杀菌剂和生物杀菌剂对该病的防效及生物杀菌剂混配对该病的防治增效作用,本研究以番茄早疫病病叶为试材,采用组织分离、菌物形态特征及rDNA-ITS基因序列分析方法鉴定病原菌;采用菌丝生长速率法和田间药效试验测定3种化学杀菌剂和2种生物杀菌剂的室内生物活性及和田间防效,并测定2种生物杀菌剂等比例混配对番茄早疫病的协同增效作用,探讨不同化学杀菌剂单剂和生物杀菌剂单剂及生物杀菌剂混配对番茄早疫病的防治效果。结果表明,引起长治地区番茄早疫病的病原菌为茄链格孢菌(Alternaria solani)。室内测定结果表明,10%苯醚甲环唑水分散粒剂、325 g·L^(-1)苯甲·嘧菌酯悬浮剂、25%咪鲜胺乳油、4%春雷霉素可湿性粉剂和10%多抗霉素可湿性粉剂对茄链格孢菌的药剂有效中浓度(EC50)分别是0.5486、0.0091、0.0595、0.4414和0.2429。田间防效试验中,第二次施药后7 d,苯醚甲环唑对番茄早疫病防效达72.54%,两种化学杀菌剂咪鲜胺和苯甲·嘧菌酯防效分别为69.94%和71.17%。生物杀菌剂多抗霉素和春雷霉素防效分别为69.65%和69.34%,二者1∶1混配后的EC50值为0.016、增效系数为1.96。混配后,第二次施药7 d后的防效为74.17%,高于单剂(3种化学杀菌剂和2种生物杀菌剂)防效。综上,10%多抗霉素可湿性粉剂和4%春雷霉素可湿性粉剂1∶1混配施用可作为山西省长治市番茄早疫病的备用药剂。本研究结果可为降低化学杀菌剂的使用量和减少农药抗药性提供理论支持,为生产上杀菌剂混用及开发防治番茄早疫病的新型高效复配剂提供依据。

水处理用絮凝剂对发光细菌的联合毒性研究

随着絮凝剂在污水污泥处理过程的广泛使用,其残留在水处理系统中可能存在的单一或联合毒性效应日益受到关注。以聚合硫酸铁(PFS)、聚合氯化铝(PAC)和聚丙烯酰胺(PAM)为研究对象,通过发光细菌单一毒性和联合毒性试验探讨其可能造成的毒性效应。结果表明:1)对于单一毒性效应,PFS、PAC和PAM对发光细菌抑制效应的半数效应浓度(EC_(50))分别为29.41、71.82和1072.64 mg/L,毒性效应大小为PFS>PAC>PAM。2)对于二元絮凝剂联合毒性效应,PFS-PAM在毒性比为1∶1混合时具有协同作用,而PAC-PAM在毒性比为1∶3和3∶1混合时均存在拮抗作用。3)采用浓度加和(CA)和独立作用(IA)模型对联合毒性进行预测,PFS-PAM组合实测值与CA模型的预测值相近,而PFS-PAC和PAC-PAM组合实测值与IA模型预测结果相近。4)三维偏差响应面结果显示,试验观测值与CA模型预测值的偏差(dCA)和试验观测值与IA模型预测值的偏差(dIA)会随着絮凝剂浓度变化而变化,CA模型在PFS和PAC浓度较高时拟合程度较好,而对于PAC-PAM体系,IA模型的拟合程度较CA模型好。研究发现,PFS和PAC对发光细菌的毒性效应较强,PFS与PAM混合使用可能会增加毒性效应,对水处理系统中的微生物造成环境风险。

萘普生与Cu^(2+)对斑马鱼胚胎的联合毒性影响

萘普生的广泛使用导致其在环境中持续输入与积累,对生态环境造成潜在的危害。金属离子Cu^(2+)虽然在自然界中普遍存在,但是萘普生和Cu^(2+)的联合毒性效应目前尚不清楚。开展了毒性预实验,根据Cu^(2+)和萘普生96 h LC 50值(毒性单位比4∶1,2∶1,1∶1,1∶2,1∶4)对斑马鱼胚胎进行混合暴露,采用相加指数(AI)法评价联合毒性影响。实验结果表明:萘普生和Cu^(2+)单独暴露对斑马鱼胚胎产生发育毒性,萘普生和Cu^(2+)所有毒性比例的联合暴露实验都对斑马鱼胚胎致死效应表现为拮抗作用。红外光谱结果对比表明:萘普生和Cu^(2+)之间能发生配合反应,所产生的配合物使二元体系联合毒性降低。