禾草灵对水稻生长和典型土壤酶活性的影响

禾草灵是一种广泛使用的除草剂,在土壤中大量残留,对非靶标生物产生危害。为探究除草剂对环境生物的毒性作用,本研究模拟水稻自然生长的环境,评估禾草灵对水稻及土壤微生物的影响。研究结果表明,低浓度禾草灵(200 μg L^-1)处理4 d对土壤微生物量没有显著影响(P>0.05);8 d时,水稻生长没有明显变化,但土壤微生物量较对照组显著升高(P<0.05)。高浓度禾草灵(1 000 μg L^-1)处理4天后,土壤脲酶、酸性磷酸酶和过氧化氢酶的活性显著下降(P<0.05),下降幅度分别为8.9%,16.6%和10.2%;处理8 d后,水稻幼苗鲜重显著降低(P>0.05),叶绿素a和叶绿素b含量分别下降了13.5%和13.3%。本研究证实高浓度的禾草灵残留会对植物和土壤微生物产生不良的影响。     

黄、渤海滨海带大气颗粒物时空分布与来源特征

PM10作为大气污染物监测的主要指标之一,探究大气PM10浓度对大气环境质量和人体健康评价具有重要意义。黄、渤海滨海带包括京、津和辽、冀、鲁、苏等工、农业大省,区域大气PM10污染的时空分布和来源特征具有复杂性和典型性。在锦州、北京、天津、烟台、青岛、连云港和盐城7个城市布设10个采样点,含7个城市点和3个农村点,开展为期一年的大气颗粒物的采样;同时,于冬季1月和夏季7月在锦州、天津和烟台进行合计60 d的加密采样,藉以确定研究区域大气PM10的时空分布和来源特征。结果表明,黄、渤海滨海带大气年均PM10总浓度为(129’18)"g·m~(-3),单月最低值出现在2015年7月盐城农村样点15"g·m~(-3),最高值为2015年3月北京城市点307"g·m~(-3)。盐城大气PM10浓度(城市点(85’27)"g·m~(-3)和农村点(66’35)"g·m~(-3))显著低于其他样点大气PM10浓度。渤海滨海带中西部的京(140’68"g·m~(-3))、津(169’60"g·m~(-3))两市大气PM10年均浓度显著高于东部的锦州(125’41"g·m~(-3))和烟台(109’31"g·m~(-3));而且黄海滨海带大气PM10年均浓度(114"g·m~(-3))显著低于渤海滨海带年均浓度(136"g·m~(-3)),总体上表现出西高东低、北高南低的特征。黄、渤海滨海带城市点和农村点年均浓度分别为(129’18)"g·m~(-3)和(112’30)"g·m~(-3);农村点春冬季大气PM10浓度和城市点浓度相当,无显著差异,夏秋季大气PM10浓度略低于城市浓度,表明农村地区大气颗粒物污染情况也较为严重,需受到关注。区域内PM10浓度季节变化整体表现为春冬高、夏秋低。利用多元回归分析初步判断黄、渤海滨海带PM10属于复合来源,大气PM10浓度约30%的变化与降水、人均能耗和沙尘天气相关。黄、渤海滨海带大气PM10浓度的昼夜变化不大,大气PM10浓度与气温呈现正相关,与风速和降水呈现负相关,表现为受各种气象因素综合作用的影响。     

环境有毒有害物质快速鉴别方法与应用

频发的污染事故严重影响环境质量,危害人群健康,事故的源解析和修复成为了关键问题。而传统的靶向分析方法无法胜任实际工作需求。因此,本研究建立了1)有毒有害物质清单;2)一种针对有毒有害物质的快速高效鉴别方法。将上述方法应用于某场地污染事件,成功筛查鉴定出30种环境高关注度物质,通过数据库比对进一步鉴定了6种危废物质,通过购买标准样品成功验证了4种物质。同时,还通过文献查阅与标样比对确认了另外2种有毒物质。因此,本研究建立的有毒有害物质快速筛查方法为实际环境中的污染物快速鉴别提供了一种可靠的、可行的方法。     

7种农药对管氏肿腿蜂的毒性及初级风险评价

为评估农药对寄生类自然天敌昆虫的安全性,选择管氏肿腿蜂(Scleroderma guani Xiao et Wu)作为受试生物,采用管测药膜法测定了3种杀虫剂、2种除草剂、2种杀菌剂对其致死效应,并根据田间推荐剂量计算暴露量,采用风险商值HQ对杀虫剂进行风险评估。结果显示,与空白对照比较,3种杀虫剂均具明显毒性作用,其中丁硫克百威、吡虫啉和呋虫胺对管氏肿腿蜂的24 h半致死量(24 h-LR50)分别为5.11、2.92和0.06 g a.i.·ha-1,农田内风险商值分别为60.23、16.64和3 105。除草剂和杀菌剂在3倍最大田间推荐剂量作用下,24 h管氏肿腿蜂死亡率均小于50%。上述结果表明,在田间推荐用量下,3种杀虫剂对管氏肿腿蜂的初级风险评价为存在高风险,建议进一步开展高级阶段风险评估或者采取合理的风险管理措施来降低风险;除草剂和杀菌剂对管氏肿腿蜂的风险可接受。     

农药环境风险评估中常用的计算毒理学模型软件

农药的大量使用为我国带来了严重的环境和健康问题,仅依靠传统生物测试和环境监测的方法已经不能满足农药风险评估的需要。利用计算毒理学模型,可以实现农药的高通量风险评估。本文主要介绍了农药环境风险评估中常用免费的EPI Suite、QSAR Toolbox和PBT Profiler等定量结构-活性关系(Quantitative Structure-Activity Relationship,QSAR)模型软件和SCIGROW、PRZM-GW、China-PEARL和EQC等环境多介质模型软件,以期能为农药的风险评估和科学管理提供参考。     

不同暴露途径下有机污染物对大鼠急性毒性的相关性研究

不同暴露途径下有机物在生物体内的吸收分布不同,导致毒性效应亦不同,研究化学品在不同暴露途径下对生物体的毒性,对化学品的安全性评价有实际意义。本文通过研究静脉注射、腹腔注射、肌肉注射与经口灌胃4种暴露途径下527个有机物对大鼠的急性毒性数据相关性,比较了不同暴露途径下大鼠对有机污染物的敏感度顺序,结果为:静脉注射>腹腔注射>肌肉注射>经口灌胃途径,静脉注射途径下log1/LD50与其他几种注射途径下的log1/LD50有较显著的相关性,但是与灌胃途径下毒性值之间的相关性较差,相关系数r的范围为0.82~0.97。通过逐项分析研究不同暴露途径下化合物对大鼠的急性毒性与生物利用度、吸收速率、消除速率以及代谢过程的关系,结果表明,导致这种差异的原因主要是有机污染物在大鼠体内的吸附动力学过程不同所致。     

蔬菜常用农药在地下水中残留风险评估

为明确蔬菜常用农药在地下水中的环境风险,运用China-Pearl和SCI-GROW模型开展地下水环境暴露评估,并根据我国成人和儿童暴露参数推导25种农药预测无效应浓度(PNEC)。研究发现,25种农药PECgw为0~18.340μg·L-1,成年人PNECgw为0.003~19.654 mg·L-1,儿童PNECgw为0.001~23.253 mg·L-1。成年人和儿童的RQgw值均小于1,表明25种农药按照登记用量使用,我国成人和各年龄阶段儿童直接饮用施用农药区域地下水的环境风险可接受。     

Impairments of cadmium on vitellogenin accumulation in the hepatopancreas of freshwater crab <Emphasis Type="Italic">Sinopotamon henanense</Emphasis>

During ovary maturation of crabs, vitellogenin (Vg), a precursor molecule of vitellin (Vn) needed for embryogenesis, can be produced in large quantities in the hepatopancreas and then transported to the ovary by the hemolymph. In the present study, effects of Cd on Vg accumulation in the hepatopancreas and Vg transportation of the freshwater crab Sinopotamon henanense were investigated. We also studied the impacts of Cd on the mRNA expression of genes involved in energy metabolism, protein metabolism, and metallothionein (MT) and glutathione (GSH) synthesis. After Cd treatment, the Vg concentration and the Vg mRNA expression in the hepatopancreas were downregulated. Pearson’s correlation coefficient showed that the Vg level in the hepatopancreas correlated positively with those of the ovary and hemolymph (correlation coefficients 0.844 and 0.749, respectively), suggesting that the Vg transport from the hepatopancreas to the ovary can be impaired by Cd. The levels of carbohydrate and protein in the hepatopancreas of Cd-exposed crabs were decreased, and an inhibited protein metabolism was also observed. Energy production related isocitrate dehydrogenase and cytochrome C oxidase mRNA expressions, and MT and GSH synthesis increased after 10 days of Cd treatment and decreased after 20 days. Cd also caused a time-dependent upregulation of malondialdehyde. Our findings showed that Cd decreased Vg accumulation in the hepatopancreas due to partially excessive energy consumption and an activated defense system in the hepatopancreas, suggesting a possible regulatory mechanism in S. henanense which is the competitive advantage of energy reserves in metabolic Cd stress responses over the high-energy flux during vitellogenesis to ensure a continuous supply of metabolic energy. Moreover, the damage of Vg accumulation in the hepatopancreas caused by Cd could lead to an insufficient accumulation of Vn in the ovary and cause a retardation of oocyte development.     

Fate of antimicrobial resistance genes in response to application of poultry and swine manure in simulated manure-soil microcosms and manure-pond microcosms

This study aimed to determine the occurrence, abundance, and fate of nine important antimicrobial resistance genes (ARGs) (sul1, sul2, tetB, tetM, ermB, ermF, fexA, cfr, and Intl1) in the simulated soil and pond microcosms following poultry and swine manure application. Absolute quantitative PCR method was used to determine the gene copies. The results were modeled as a logarithmic regression (N?=?mlnt?+?b) to explore the fate of target genes. Genes sul1, Intl1, sul2, and tetM had the highest abundance following the application of the two manure types. The logarithmic regression model fitted the results well (R ² values up to 0.99). The reduction rate of all genes (except for the genes fexA and cfr) in manure-pond microcosms was faster than those in manure-soil microcosms. Importantly, sul1, intl1, sul2, and tetM had the lowest reduction rates in all the samples and the low reduction rates of tetM was the first time to be reported. These results indicated that ARG management should focus on using technologies for the ARG elimination before the manure applications rather than waiting for subsequent attenuation in soil or water, particularly the ARGs (such as sul1, intl1, sul2, and tetM investigated in this study) that had high abundance and low reduction rate in the soil and water after application of manure.     

Elemental mobility in sulfidic mine tailings reclaimed with paper mill by-products as sealing materials

Environmental Science and Pollution Research - Sealing layers made of two alkaline paper mill by-products, fly ash and green liquor dregs, were placed on top of 50-year-old sulfide-containing...