黄酒中尿素的测定

二乙酰－肟分光光度法是测定黄酒等样品中尿素含量的一种快速、灵敏、简便的方法。样品中的尿素与显色试剂在沸水浴中发色１０￣１５ｍｉｎ后比色测定，显色的线性范围在０￣９μｇ尿素之间。测得的结果中包含了瓜氨酸的含量。样品中酒精和葡萄糖的存在不干扰测定。以标准加入法进行定量，从而使该方法的回收率和重现性大大提高，可满足一般痕量分析的要求。     

纳米硫化镉对A549细胞的损伤研究

研究纳米硫化镉(Nano-Cd S)材料对肺癌细胞系A549的毒性及氧化损伤作用。培养A549细胞,经传代后接种于6孔板中,每孔2 m L完全培养基,接种次日进行染毒。用直径20~30 nm、长度80~100 nm的Nano-Cd S进行染毒,染毒浓度分别为0、5、10、20、40和80 mg·L~(-1)。染毒24 h后用MTT检测细胞存活率,以存活率在80%左右的浓度为后续实验染毒浓度。应用流式细胞技术,用荧光探针法检测A549细胞的活性氧(reactive oxygen species,ROS)含量,PI-Annexin-V法检测细胞凋亡情况;用试剂盒检测细胞中超氧化物岐化酶(superoxide dismutase,SOD)和过氧化氢酶(catalase,CAT)活性以及丙二醛(malondialdehyde,MDA)含量,判断细胞氧化损伤情况。不同浓度Nano-Cd S处理细胞24 h之后,细胞存活率随剂量的增加而下降,浓度为10、20、40和80μg·L~(-1)时,存活率分别为(88.71%±0.80%)、(81.93%±3.06%)、(75.23%±1.13%)和(70.66%±5.63%),且各组间差异均具有统计学意义(P0.05)。以浓度为10和20 mg·L~(-1)的Nano-Cd S染毒24 h后,胞内ROS含量和细胞凋亡率随染毒剂量的增加而增加(P0.05);浓度为10 mg·L~(-1)时,细胞凋亡率为(6.26%±0.44%)。与对照相比,各染毒组SOD和CAT活性和MDA含量升高,20 mg·L~(-1)染毒组SOD和CAT活性和MDA含量高于10 mg·L~(-1)染毒组(P0.05)。研究表明,纳米硫化镉能引起A549细胞的氧化损伤和细胞凋亡,具有明显的细胞毒性。     

Stereoisomeric profiling of pharmaceuticals ibuprofen and iopromide in wastewater and river water, China

Stereoisomeric compositions can provide insights into sources, fate, and ecological risks of contaminants in the environment. In this study, stereoisomeric profiles of ibuprofen and iopromide were investigated in wastewater and receiving surface water of the Pearl River Delta, south China. The enantiomeric fraction (EF) of ibuprofen was 0.108–0.188 and 0.480, whereas the isomer ratio (IR) of iopromide was 1.426–1.673 and 1.737–1.898 in the influent and final effluent, respectively, suggesting stereoselective degradation occurred for both pharmaceuticals during wastewater treatment. Ibuprofen showed enantioselective degradation in the anaerobic, anoxic, and aerobic conditions, whereas iopromide displayed isomer-selective degradation only under the aerobic condition. In the river waters, the EF of ibuprofen was 0.130–0.327 and the IR of iopromide was 1.500–2.531. The results suggested that pharmaceuticals in the mainstream Pearl River were mainly from discharge of treated wastewater, whereas in the tributary rivers and urban canals, direct discharge of untreated wastewater represented a significant contribution. The IR of iopromide can be an applicable and efficient tracer for wastewater discharge in the environment.     

Distribution pattern, behavior, and fate of antibacterials in urban aquatic environments in South China

Occurrence, behavior and fate of several groups of antibacterials were investigated in municipal wastewater, sewage sludge, and urban river water in China. Fluoroquinolones (e.g., ciprofloxacin, norfloxacin, and ofloxacin), macrolides (dehydroerythromycin, roxithromycin, and clarithromycin), sulfonamides (sulfamethoxazole and sulfamethazine) and trimethoprim were ubiquitously detected in the wastewater in China. Fluoroquinolones were generally the most abundant in the raw sewage, with a maximum concentration of up to 6415 ng L(-1) observed for norfloxacin. Sulfonamides and macrolides transported predominantly in the aqueous phase. A median percentage of 67% of sulfonamides and 86% of macrolides remained in the final effluent after treatment in sewage treatment plants. On the contrary, sorption played a significant role in transport of fluoroquinolones and approximately half of the fluoroquinolones finally ended up and persisted in the dewatered sludge. In the urban section of the Pearl River at Guangzhou, sulfonamides, trimethoprim, and macrolides were widely present at median concentrations of 22-735 ng L(-1), whereas fluoroquinolones were only occasionally detected at 2-152 ng L(-1), probably due to their strong tendency of partition to sediment and/or photodegradability. The result of principal components analysis suggests input of non-sewage derived sulfamethazine in the Pearl River. Seasonal variations of the antibacterials distribution in the wastewater are mainly ascribed to different consumption. Dilution effect by precipitation, however, also plays an important role in seasonal distribution of the antibacterials in the Pearl River.     

Long-term estimation of plastic material resources from end-of-life vehicles in China: a scenario analysis considering multiple industry standards

Journal of Material Cycles and Waste Management - The recycling and treatment of plastic waste become an increasingly serious environmental degradation challenge. To promote the recycling of...     

The role of N6-methyladenosine methylation in environmental exposure-induced health damage

Environmental Science and Pollution Research - The health risks caused by environmental pollution have long been of substantial concern. With the development of epigenetics, a large number of...     

FeCl3改性污泥生物炭对水中吡虫啉的吸附性能研究

以脱水污泥为原料,制备污泥生物炭（SBC）和FeCl₃改性污泥生物炭（Fe-SBC）处理低浓度吡虫啉（IMI）废水（浓度为10 mg·L^-1）,考察SBC和Fe-SBC对IMI的吸附性能及影响因素,并探究其吸附机理.采用SEM、XRD、FTIR、BET及元素分析等探得污泥生物炭FeCl₃改性成功.Fe-SBC对IMI的最大吸附量为4.915 mg·g^-1,是SBC的1.97倍,表现出更好的IMI吸附性能.pH和离子强度的变化对Fe-SBC的吸附性能影响较小,最大波动幅度分别为4.4%和7.8%.两种生物炭对IMI的吸附均符合准二级动力学模型,Freundlich模型可以更好地描述其等温吸附曲线.热力学研究表明,SBC吸附IMI是非自发吸附,而Fe-SBC是自发吸附.Fe-SBC对IMI的吸附机理包括静电作用力、氢键作用力及π-π键相互作用力.多次热解再生后的Fe-SBC对IMI的去除率仍可达93.088%.     

硫自养填充床生物反应器去除水中的高氯酸盐

建立了硫自养填充床生物反应器用于水中ClO4-的去除,考察水力停留时间(HRT)、水温的影响及副产物产生规律。结果表明,当进水ClO4-浓度为22.40~21.07 mg/L时,逐步缩短HRT为12、8、4、2、1.5和1 h,经4~6 d的适应期,反应器对其去除率可达99%以上;低浓度的NO3--N(2.17 mg/L)的存在对ClO4-的降解不产生抑制,两者可同步去除;3℃以内的水温波动对其去除影响较小,较大的温度波动(-8℃)会造成去除率下降;Cl-作为惟一还原产物,其浓度增多符合化学计量比。同时,研究证实了硫歧化反应的发生,出水SO42-浓度的增加量大于理论值,S2-离子浓度较低(4-完全去除时,出水pH值比进水降低约1.1个单位。     

Fenton降解涂装废水的因素影响及动力学分析

以江苏某电动自行车制造企业的涂装废水为研究对象,采用单因素和响应面优化Fenton氧化处理的反应条件,分析了其动力学过程。结果表明：在pH=3.21、n(H₂O₂/Fe²⁺)=8∶1、m(H₂O₂/COD)=4.17∶1、氧化反应时间为120 min的条件下,COD和TP的去除率均达到最高,分别为81.32%和98%,其降解过程符合一级反应动力学,室温下降解速率常数k为0.014 2 min⁻¹,活化能为4.76 kJ·mol⁻¹。在pH=3.21、n(H₂O₂/Fe²⁺)=8∶1、m(H₂O₂/COD)=0.78∶1、反应时间120 min的条件下,Fenton半氧化体系对COD去除率可达42.5%左右,处理后废水的B/C比由0.12提高至0.35。综合经济因素,认为Fenton半氧化与生物处理工艺耦合处理实际涂装废水更佳。     

民营企业安全生产 "4S"监管体系的构建与应用

众所周知,浙江省的民营经济非常发达,通过不断深化产权体制改革,已形成了以民营经济为主体的经济结构,民营经济总量已占全省经济总量的一半以上。随着民营企业的不断发展壮大,一方面给浙江经济带来了蓬勃生机,另一方面也存在着诸多问题。根据浙江省安监部门公布的数据显示,