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。     

Pesticide residue removal in classic domestic processing of tomato and its effects on product quality

This study was undertaken to evaluate the effectiveness of several household practices (washing with water or acidic, alkaline, and oxidizing solutions, and peeling) in minimizing pesticide residue contamination of tomatoes, as well as the impact on the quality of the treated fruit. Tests were performed using two systemic fungicides (azoxystrobin and difenoconazole) and one contact fungicide (chlorothalonil). Solid-liquid extraction with low temperature partition (SLE/LTP) and liquid-liquid extraction with low temperature partition (LLE/LTP) were used to prepare the samples for pesticides determination by gas chromatography. Washing the tomatoes with water removed approximately 44% of chlorothalonil, 26% of difenoconazole, and 17% of azoxystrobin. Sodium bicarbonate (5%) and acetic acid (5%) solutions were more efficient, removing between 32 and 83% of the residues, while peeling removed from 68 to 88% of the pesticides. The washing solutions altered some fruit quality parameters, including acidity and chroma, and also caused weight loss. Acetic acid (0.15 and 5%) and hypochlorite (1%) solutions had the greatest effect on these parameters.     

Renewable energy sources: conflicts and opportunities in a changing landscape

Regional Environmental Change - Replacement of conventional energy sources with renewables such as solar panels and wind turbines requires adequate land. Impact assessments should be conducted to...     

Atrazine contamination in agricultural soils from the Yangtze River Delta of China and associated health risks

Atrazine is one of the most widely applied and persistent herbicides in the world. In view of limited information on the regional contamination of atrazine in soils in China, this study investigated the spatial distribution and environmental impacts of atrazine in agricultural soils collected from the Yangtze River Delta (YRD) as an illustrative analysis of rapidly developing regions in the country. The results showed that the concentrations of atrazine in the YRD agricultural soils ranged from <1.0 to 113 ng/g dry weight, with a mean of 5.7 ng/g, and a detection rate of 57.7 % in soils. Pesticide factory might be a major source for the elevated levels of atrazine in Zhejiang Province. The contamination of atrazine was closely associated with land use types. The concentrations and detection rates of atrazine were higher in corn fields and mulberry fields than in rice paddy fields. There was no significant difference in compositions of soil microbial phospholipids fatty acids among the areas with different atrazine levels. Positive relationship (R = 0.417, p < 0.05, n = 30) was observed between atrazine and total microbial biomass. However, other factors, such as soil type and land management practice, might have stronger influences on soil microbial communities. Human health risks via exposure to atrazine in soils were estimated according to the methods recommended by the US EPA. Atrazine by itself in all the soil samples imposed very low carcinogenic risks (<10^?6) and minimal non-cancer risks (hazard index <1) to adults and children.     

春季香溪河库湾CODMn时空分布及其影响因子初探

于2012年春季在香溪河库湾合理布置断面观测,分析水体高锰酸盐指数(CODMn)的时空分布特征,并对CODMn与水体中叶绿素a、溶解氧(DO)、水体垂向稳定系数、总氮(TN)和溶解性硅酸盐(D Si)进行相关分析,以期为香溪河流域有机污染的治理提供支持和指导。结果表明：春季香溪河库湾CODMn浓度变化范围为1.40～5.36 mg/L,4月CODMn均值明显高于3月和5月,为366 mg/L,整个春季CODMn浓度从下游至上游呈现明显增大的趋势。相关分析发现,春季水华暴发期间,CODMn与叶绿素a显著正相关(分别为072和074),而在未暴发水华的3月二者的相关性不显著。浮游植物和水体稳定系数是影响CODMn变化的主要因素。倒灌异重流使得高含氮、低CODMn浓度的长江干流水体进入库湾下游并稀释CODMn浓度。CODMn与DO在3月和5月的弱相关关系为香溪河CODMn特殊的分布特征提供了其它合理的解释,其分布特征受多种因素的共同影响。春季库湾上游有机污染趋于恶化,限制支流特别是上游污染物的排放是改善有机污染现状的有效途径     

Comparative Thermodynamic Study on the Contribution of the Autocondensation and Copolymerization Reactions for the Tannins of the Subspecies of Acacia nilotica

Autocondensation and copolymerization reactions of the Acacia nilotica subspecies tomentosa (Ant) and the subspecies adansonii (Ana) tannins extracts solutions have been studied at several pH values by thermomechanical analyzer. Results of chemical analysis of these tannins revealed that the studied tannins, Ant and Ana contained high percentages of extractable tannins (54 and 57 %) for and polyphenolic materials (78 and 80 %) respectively. Different hardeners such as paraformaldehyde, Urea and pMDI were added at different ratios and their polycondensation reactions was studied and compared with their autocondensation ones. The aim was to evaluate the tannins suitability for the production of commercially and technically viable tannin adhesives with reduced Formaldehyde emission for wood products and to study the interference between the autocondensation and the copolymerization reaction. The obtained results of autocondensation reaction for both of the tannins studied showed that the best Young’s modulus values for Ant (3,500 and 2,750 MPa) and Ana (2,650 and 2,620 MPa) were obtained at pH 5 and 7. The Young’s modulus values obtained by the tannins Ant were higher than those achieved by Ana. This indicates that the Ant is more reactive than Ana. These results were also in line with results achieved by the gel time for both of the tannins. Gel time results indicate that the reactivity of both tannins increased towards alkalinity with Ana being more reactive at alkaline pH. Addition of 8 % of paraformaldehyde was adversely affecting the autocondensation reactions, as the best Young’s modulus values were achieved at pH 4 for Ant tannins. As for Ana the higher Young’s modulus values (2,000 and 2,310 MPa) were achieved at pH 5 and 7. This indicates that autocondensation reaction was contributed to the final network of the copolymerization reaction. When smaller ratio of paraformaldehyde and Urea (5 %) was added to Ant tannins it favors the autocondensation reaction and the best Young’s modulus values were obtained at pH 5 and 7. Addition of pMDI (10–30 %) was found to decrease the temperature of copolymerization and the obtained Young’s modulus values by Ant were lower than those obtained by autocodensation reaction. Best Young’ modulus values were obtained by Ant at pH 5 and 7. Ana gave the best Young’s modulus values at pH 4 and 5 indicating that the autocondensation appears to depress the copolymerization reactions. The obtained results by both reactions were very important from technical and economical point of view as they concluded that it is very possible to produce adhesives system with zero emission depending on the tannins autocondensation reaction and pH values. Reduction of formaldehyde emission was also possible upon addition of smaller amount of paraformaldehyde and Urea.     

Biodegradability of Epoxidized Soybean Oil Based Thermosets in Compost Soil Environment

In this study, bio-thermoset from epoxidized soybean oil (ESO) was prepared in the presence of methylhexahydrophthalic anhydride curing agent and 2-ethyl-4-methylimidazole catalyst. The crosslink densities of the synthesized ESO are ranged from 0.109 × 10^?3 to 0.308 × 10^?3 mol/cm³. The ESO bio-thermosets were exposed to the soil-burial test for 8 months. Weight change and morphology of the degraded ESO specimens were assessed. It was found that the weight loss of ESO was governed by the materials compositions, crosslink density and the soil-burial exposure time. The 3 mm thickness ESO bio-thermosets with crosslink density of 0.109 × 10^?3 mol/cm³ had fully biodegraded after soil-burial for 6 months. In addition, 16S rDNA sequencing was carried out to identify the soil microorganisms. It was suggested that Comamonas sp., Bacillus sp., Streptomyces sp. and Acinetobacter sp. are the possible soil microbes that degrade the ESO bio-thermosets in the compost soil environment.     

Influence of soil and hydrocarbon properties on the solvent extraction of high-concentration weathered petroleum from contaminated soils

Petroleum ether was used to extract petroleum hydrocarbons from soils collected from six oil fields with different history of exploratory and contamination. It was capable of fast removing 76–94 % of the total petroleum hydrocarbons including 25 alkanes (C₁₁–C₃₅) and 16 US EPA priority polycyclic aromatic hydrocarbons from soils at room temperature. The partial least squares analysis indicated that the solvent extraction efficiencies were positively correlated with soil organic matter, cation exchange capacity, moisture, pH, and sand content of soils, while negative effects were observed in the properties reflecting the molecular size (e.g., molecular weight and number of carbon atoms) and hydrophobicity (e.g., water solubility, octanol–water partition coefficient, soil organic carbon partition coefficient) of hydrocarbons. The high concentration of weathered crude oil at the order of 10⁵ mg kg^?1 in this study was demonstrated adverse for solvent extraction by providing an obvious nonaqueous phase liquid phase for hydrocarbon sinking and increasing the sequestration of soluble hydrocarbons in the insoluble oil fractions during weathering. A full picture of the mass distribution and transport mechanism of petroleum contaminants in soils will ultimately require a variety of studies to gain insights into the dynamic interactions between environmental indicator hydrocarbons and their host oil matrix.     

循环流化床锅炉燃煤技术热电厂生命周期评价

运用生命周期评价方法,应用Gabi5.0软件对采用循环流化床锅炉燃煤技术的热电企业进行资源耗竭和环境影响分析,计算各生产单元生命周期清单的全球变暖潜值、酸化效应潜值、富营养化潜值、非生物资源耗竭潜值、人体毒性潜值以及光化学烟雾和臭氧生成潜值等主要环境影响类型,对燃煤发电过程进行生命周期评价。结果表明,全球变暖和非生物资源耗竭为发电运行过程中主要的环境影响因素,分别占53%和15.05%;锅炉燃烧阶段的环境影响最重,占整个生命周期影响值的77.12%,并且除生物耗竭潜值外的其他5项指标均为发电运行阶段各个单元中最高。采用SNCR脱硝技术减少燃烧过程中NOx的排放量,并对该技术方案进行生命周期评价,比较方案实施前后的环境影响。     

Gas-phase and semivolatile organic emissions from a modern nonroad diesel engine equipped with advanced aftertreatment

ABSTRACT

U.S. Tier 4 Final and Euro Stage IV and V regulations for nonroad compression-ignition engines have led to the development of exhaust aftertreatment technologies optimized for nonroad engines and duty cycles. In this study, several aftertreatment configurations consisting of state-of-the-art diesel oxidation catalysts (DOCs), diesel particulate filters (DPFs), copper (Cu) zeolite– and vanadium-based selective catalytic reduction (SCR) catalysts, and ammonia oxidation (AMOX) catalysts are evaluated using both nonroad transient (NRTC) and steady (8-mode NRSC) cycles in order to understand both component- and system-level effects of diesel aftertreatment on gas-phase, semivolatile, and particle-phase and particle-bound unregulated organic emissions. Organic emissions reported in this work include total hydrocarbon (THC), n-alkanes, branched alkanes, saturated cycloalkanes, aromatics, aldehydes, ketones, hopanes, steranes, and soluble organic fraction (SOF). Brake-specific emissions are reported for four configurations, including engine-out, DOC+CuZ-SCR+AMOX, V-SCR+AMOX, and DOC+DPF+CuZ-SCR+AMOX, and conversion of engine-out emissions is reported for the three aftertreatment configurations. Mechanisms responsible for the reduction of organic species are discussed in detail. This summary of emissions from a current nonroad diesel engine equipped with advanced aftertreatment can be used to more accurately model the impact of anthropogenic emissions on the atmosphere with tools such as the U.S. Environmental Protection Agency’s Motor Vehicle Emissions Simulator (MOVES2014a) model.

Implications: Anthropogenic emissions are a source of significant human health and environmental risk. This study, focused on the treatment of exhaust emissions from a modern nonroad diesel engine with a variety of aftertreatment configurations, examines the impact that human industrial activity can have on air pollution. In particular, we focus on the remediation of gas-phase and semivolatile organic emissions by emission reduction technologies. This detailed summary of emissions from a current nonroad diesel engine equipped with advanced aftertreatment can be used to more accurately model the impact of anthropogenic emissions on the atmosphere with tools such as the U.S. Environmental Protection Agency’s MOVES2014a model.