拟除虫菊酯农药在茶叶中应用的安全性评价

采用田间模拟施药与气相色谱法研究了7种拟除虫菊酯农药在茶园生态环境中的降解动态,茶叶加工过程中的降解和泡茶过程的浸出率及其主要影响因子。根据实验结果推算出通过饮茶进入人体的农药量,结合农药的毒理特性,对拟除虫菊酯农药在茶园生态环境中应用的安全性进行了综合评价。结果表明,拟除虫菊酯农药在茶园中应用的安全性显著高于有机磷农药,在拟除虫菊酯农药之间,其安全性也有较大差异。本研究不仅为茶园使用农药的选择提供了依据,而且首次提出了一种农药对人体安全性的定量评价体系。     

含铜多金属复杂矿区的一株浸矿细菌的分离与鉴定

为寻找新的浸矿细菌,从江西城门山矿区硫化矿矿坑水中使用平板分离法得到了一株能够浸矿的细菌,命名为CMS.经电镜和生理生化试验,鉴定该菌株为革兰氏阴性细菌,短杆状,菌体大小为(0.4±0.1)靘祝±0.5)靘, 最适生长温度为25～30 ℃,最适pH值为2.0,化能自养型,能利用亚铁、单质硫和葡萄糖生长,不能利用硫代硫酸钠、蛋白胨生长.16S rRNA系统发育树的结果表明,CMS菌株与嗜酸氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans,简称A.f)AFY菌株位于系统发育树一个同的分支中,相似度99.72%.克隆其代谢系统关键基因亚铁氧化酶(Iro protein)基因并测定其序列,与其他相关菌株比对,结果显示编码区的核酸序列与报道序列完全一致.另外,其铁闪锌矿(ZnFe)S摇瓶浸出试验显示,在浸出28 d后,含菌株的摇瓶的锌离子质量浓度即达到615.50 mg·L-1,而无菌浸出仅有392.25 mg·L-1.     

鼓风曝气充氧性能与曝气器水深关系

应用相似原理,建立曝气器清水充氧性能与曝气器浸没深度变化的数学模式,为曝气器充氧性能科学预测和曝气工艺设计提供可靠的参数。     

镉污染农田农业生态整治与安全高效利用模式

传统的镉污染治理策略多以改造和净化环境、恢复土壤质量为宗旨。作者从有效利用污染农田的角度,提出了农业生态整治策略,即将污染农田作为一种特殊资源,通过发掘利用生物（植物）自身的耐（抗）镉基因,使污染土地在农业领域重新获得安全而高效的利用。介绍了对某铀矿区近40hm²镉污染农田进行治理利用的成功实践。通过采用桑蚕生产模式替代粮作生产模式,杜绝了污灌污染,消除了食物链中镉的危害,使土壤生产力得到恢复,农田年均产值比水稻模式提高2880元/hm²,比种玉米提高8880元/hm²,利税增加1980元/hm²,耕层土壤镉含量年平均下降1.33mg/kg。还论述了镉在桑树中的分布特征及其对桑树生长和蚕茧质量的影响。     

Performance of biotic indices in comparison to chemical-based Water Quality Index (WQI) in evaluating the water quality of urban river

In order to evaluate the water quality of one of the most polluted urban river in Malaysia, the Penchala River, performance of eight biotic indices, Biomonitoring Working Party (BMWP), BMWP^Thai, BMWP^Viet, Average Score Per Taxon (ASPT), ASPT^Thai, BMWP^Viet, Family Biotic Index (FBI), and Singapore Biotic Index (SingScore), was compared. The water quality categorization based on these biotic indices was then compared with the categorization of Malaysian Water Quality Index (WQI) derived from measurements of six water physicochemical parameters (pH, BOD, COD, NH₃-N, DO, and TSS). The river was divided into four sections: upstream section (recreational area), middle stream 1 (residential area), middle stream 2 (commercial area), and downstream. Abundance and diversity of the macroinvertebrates were the highest in the upstream section (407 individual and H′?=?1.56, respectively), followed by the middle stream 1 (356 individual and H′?=?0.82). The least abundance was recorded in the downstream section (214 individual). Among all biotic indices, BMWP was the most reliable in evaluating the water quality of this urban river as their classifications were comparable to the WQI. BMWPs in this study have strong relationships with dissolved oxygen (DO) content. Our results demonstrated that the biotic indices were more sensitive towards organic pollution than the WQI. BMWP indices especially BMWP^Viet were the most reliable and could be adopted along with the WQI for assessment of water quality in urban rivers.     

Production of activated carbon from walnut shell by CO2 activation in a fluidized bed reactor and its adsorption performance of copper ion

Journal of Material Cycles and Waste Management - Low-cost and effective activated carbon for copper ion adsorption was prepared from walnut shell by CO2 activation in a fluidized bed. The effects...     

Coffee,its roasted form,and their residues cause birth failure and shorten lifespan in dengue vectors

Environmental Science and Pollution Research - In dengue mosquitoes, successful embryonic development and long lifespan are key determinants for the persistence of both virus and vector. Therefore,...     

Effects of pre-oxidation and adsorption on haloacetonitrile and trichloronitromethane formation during subsequent chlorination

In this study, the effects of pre-oxidants permanganate (PM), persulfate (PS), hydrogen peroxide (PO), and ozone (OZ)) and/or adsorption on pseudoboemite-chitosan shell magnetic nanoparticles (ACMNs) on haloacetonitrile (HAN) and trichloronitromethane (TCNM) formation from aspartic acid (Asp; positive charge) and/or histidine (His; negative charge) were compared. Asp and His apparently do not interact in aqueous solution during chlorination. Asp and/or His can undergo partially oxidation by PM, but are recalcitrant to direct oxidation by PS and PO. Pre-oxidation with OZ decreases the formation of HANs but increases the formation of TCNM. ACMN prefers to adsorb Asp over His in the competitive sorption of coexisting Asp and His because of attractive electrostatic interactions. The rank order for the effect of the pre-oxidants and ACMN adsorption on dichloroacetonitrile and trichloroacetonitrile formation is OZ and ACMN adsorption > PM and ACMN adsorption > PS and ACMN adsorption > PO and ACMN adsorption; that for the effect of the pre-oxidants and ACMN adsorption on TCNM formation is PM and ACMN adsorption > PS and ACMN adsorption > PO and ACMN adsorption > OZ and ACMN adsorption. The favored adsorption of Asp over His by ACMN is weakened by pre-oxidation.

     

Fine particle migration and collection in a wet electrostatic precipitator

Electrostatic precipitation is considered as an effective technology for fine particle removal. A lab-scale wet electrostatic precipitator (ESP) with wire-to-plate configuration was developed to study particle migration and collection. The performance of the wet ESP was evaluated in terms of the corona discharge characteristics, total removal efficiency and fractional removal efficiency. The corona discharge characteristics and particle removal abilities of the wet ESP were investigated and compared with dry ESP. Particle removal efficiency was influenced by discharge electrode type, SO₂ concentration, specific collection area (SCA) and particle/droplet interaction. Results showed that the particle removal efficiency of wet ESP was elevated to 97.86% from 93.75% of dry ESP. Three types of discharge electrodes were investigated. Higher particle removal efficiency and larger migration velocity could be obtained with fishbone electrode. Particle removal efficiency decreased by 2.87% when SO₂ concentration increased from 0 ppm to 43 ppm as a result of the suppression of corona discharge and particle charging. The removal efficiency increased with higher SCA, but it changed by only 0.71% with the SCA increasing from 25.0 m²/(m³/s) to 32.5 m²/(m³/s). Meanwhile, the increasing of particle and droplet concentration was favorable to the particle aggregation and improved particle removal efficiency.

Implications: This work tends to study the particle migration and collection under spraying condition. The performance of a wet electrostatic precipitator (ESP) is evaluated in terms of the corona discharge characteristics, total particle removal efficiency, and fractional particle removal efficiency. The effects of water droplets on particle removal, especially on removal of particles with different sizes, is investigated. The optimization work was done to determine appropriate water consumption, discharge electrode type, and specific collection area, which can provide a basis for wet ESP design and application.     

Medium-scale gasification of oil palm empty fruit bunch for power generation

Journal of Material Cycles and Waste Management - This paper focuses on the performance of oil palm empty fruit bunch (EFB) gasification using a medium-scale downdraft gasifier for power...