Residue levels and dietary risk assessment of fluopimomide,pyraclostrobin and its metabolite BF-500–3 in garlic ecosystems under field conditions

Environmental Science and Pollution Research - To evaluate the residue levels of fluopimomide, pyraclostrobin and its metabolite BF-500–3 in garlic ecosystems, supervised garlic field trials...     

絮凝-电解氧化联合处理氰化提金废水

采用絮凝-电解氧化联合技术处理氰化废水,主要研究了聚硅酸铝铁 (PSAF) 添加量、絮凝时间、pH、电压、电解时间、极板间距对总氰(CN_T)、游离氰(CN⁻)、Cu、Zn离子去除率的影响,并对其反应机制做了分析。研究表明,当PSAF添加量为2 g·L⁻¹,絮凝时间为30 min,pH为9条件下,CN_T、CN⁻、Zn、Cu离子的去除率分别可达42.97%、100%、84.40%、34.88%。Zn(CN)₄²⁻、Cu(CN)₃²⁻、CN⁻的吸附量分别为567.88、89.76、439.74 mg·L⁻¹。以钛板为阴极,石墨板为阳极,采用一阴两阳体系对絮凝后液进行电解氧化实验,在电压为3 V、电解时间为2 h、极板间距为10 mm条件下,CN_T、CN⁻、Zn、Cu离子的去除率可达91.70%、100%、99.15%、94.49%。絮凝过程中Zn(CN)₄²⁻、Cu(CN)₃²⁻、CN⁻的去除是由电荷中和和化学吸附共同作用的,其中电荷中和起主要作用。Zn(CN)₄²⁻、Cu(CN)₃²⁻、CN^-的化学吸附主要归因于其与PSAF水解产生的羟基阳离子发生交换反应。XRD分析表明,加入酸性絮凝剂PSAF的瞬间,部分Zn(CN)₄^2-反应为Zn(CN)₂沉淀。电解氧化过程中Zn(CN)₄²⁻、Cu(CN)₃²⁻破络释放的氰根会被阳极表面产生的O₂、·OH完全氧化为N₂和CO₂,Zn、Cu离子在阴极板电沉积而被去除。     

Solid phase extraction with pyrenebutyric acid-bonded silica for analysis of polychlorinated biphenyls in sewage water by gas chromatography-mass spectrometry

A solid phase extraction (SPE) method using pyrenebutyric acid-bonded silica (PYB) as sorbent was developed to determine 23 polychlorinated biphenyls (PCBs) in sewage water by gas chromatography-mass spectrometry (GC-MS). Factors were optimized in SPE procedures including elution solvent, pH, and cartridge burden. The recoveries of 23 PCB congeners were 69.44-111.91% under optimized conditions. Comparisons were also conducted among PYB-SPE, C(18)-SPE and United States Environmental Protection Agency 608 (USEPA608) methods in the analysis of PCBs in sewage water samples. The results showed that the performance of PYB-SPE method was similar with USEPA608 method and better than C(18)-SPE method. Both PYB-SPE and USEPA608 methods were then employed to analyze PCBs in real spiked sewage water samples. The recoveries of PCB congeners determined by PYB-SPE method ranged from 70.6% to 92.4% in real spiked sewage water samples which were identified to be in accordance with USEPA608 method. Limits of detection (LOD) were in the range of 0.06-0.22ngL(-1) for PCB congeners. The optimized PYB-SPE method was successfully applied to the determination of PCBs in sewage water samples.     

Effects of four chlorobenzenes on serum sex steroids and hepatic microsome enzyme activities in crucian carp, Carassius auratus

Four chlorobenzenes (chlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, p-chloro-methylbenzene) were administrated to the crucian carps (Carassius auratus) by peritoneal injections in the laboratory for 30 days. Serum testosterone and 17 beta-estradiol concentrations were detected using radioimmunology assay (RIA), and the activities of two hepatic microsome enzymes, glutathione s-transferase (GST) and UDP-glucuronosyltransferase (UDPGT), were measured using the modified methods as described by Habig and Owens. Results showed that the four chlorobenzenes caused significant increases in serum testosterone concentration in the crucian carps (P < 0.05) compared to the controls, but they caused no significant effect on 17 beta-estradiol level. All test chemicals caused a change in hepatic GST activity in crucian carps, with significant increases in enzyme activity (P < 0.05). Chlorobenzene, 1,3-dichlorobenzene and p-chloro-methylbenzene resulted in a marked inhibition to UDPGT activity in crucian carp (P < 0.05) except 1,4-dichlorobenzene. The changes in hepatic microsome enzyme activities may have resulted in the alterations of serum sex steroids levels in the crucian carps. The results indicated that these four chlorobenzenes may result in the changes of endocrine functions and may affect the reproductive success of this and other species.     

突发性环境污染事故应急预警系统发展探讨

在介绍突发性环境污染事故的概念、类型与特性的基础上,综述了近年来国内外对这一领域的研究进展．并结合“5S”技术提出突发性环境污染事故应急预警系统的全程模拟。     

污染底泥及其间隙水分层特性的模拟实验研究

底泥冲刷沉降、再悬浮是作用于水环境内源污染的主要因素,而底泥间隙水的污染释放则是主要途径。通过底泥培养实验,研究了污染底泥及其间隙水的分层特性。结果表明,底泥及其污染物具有显著的分层特性。底泥间隙水中CODMn随深度的增加略有下降的趋势;底泥湿容重和干容重呈增大的趋势;含水率随底泥深度的增加而减小。底泥深度对底泥泥沙颗粒的级配有很大影响,在表层以细颗粒为主,随着深度的增加．底泥粒径增加,但趋势衰减较快。这对底泥冲刷作用下的再悬浮有很大影响。     

氯化汞对小鼠睾丸生殖细胞的DNA损伤作用

探索氯化汞对雄性小鼠生殖细胞毒性的分子遗传机制。分别以 0 .0 1、0 .10、1.0 0 mmol/L的氯化汞体外处理小鼠睾丸细胞和以 0 .5、1.0、5 .0 μmol/kg的氯化汞体内暴露小鼠 ,应用单细胞凝胶电泳技术检测生殖细胞 DNA的损伤。体外处理 3种剂量组小鼠睾丸生殖细胞 DNA损伤率显著高于阴性对照组 ( 0 mmol/L组 ,P<0 .0 0 1) ;0 .1、1.0 mmol/L剂量组慧星细胞迁移率显著高于阴性对照组 ( P<0 .0 0 1,P<0 .0 5 )。体内暴露 3种浓度氯化汞组小鼠睾丸生殖细胞 DNA损伤率显著高于阴性对照组 ( 0μmol/kg,P<0 .0 0 1) ,5 .0 μmol/kg组慧星迁移率显著高于阴性对照组 ( P<0 .0 5 )。一定剂量的氯化汞处理引起生殖细胞 DNA损伤作用可能是氯化汞细胞毒性的机制之一。     

印染废水生物强化处理技术研究进展

印染废水是国内外公认的难处理的工业废水之一 ,活性污泥法是目前最常用的处理方法 ,但还存在诸多问题。在分析中 ,主要从生物强化技术、固定化微生物技术和微生物活性增加技术等方面 ,总结了废水生物处理技术强化研究进展 ,并讨论了今后的研究方向。     

饮用水中硝酸根的催化还原研究进展

由于化肥的过度使用 ,造成地下水中硝酸盐的污染日益严重。饮用水中高浓度的硝酸盐对人类健康会产生极大的威胁。本文综述了催化还原脱除水中硝酸根的研究进展和现状 ,并对其发展趋势进行了简单的论述。     

红色非硫光合细菌的生长特性研究

红色非硫光合细菌菌种从城市污水处理厂活性污泥中分离得到,对红色非硫光合细菌的生长规律及其影响因素进行研究,试验表明在进行污水处理时所用的红色非硫光合细菌的最佳培养条件为接种量2%,pH7～8,光照强度为1500lx,光照厌氧条件下培养3～5d。这为红色非硫光合细菌应用于染料有机化工废水处理的进一步研究提供了理论依据。