Review and prospects of mining chemical dust suppressant: classification and mechanisms

Environmental Science and Pollution Research - Coal mine pollution is a serious threat to the mine safe production and occupational health of miners. Chemical dust suppression can effectively...     

DRYING UP OF THE YELLOW RIVER:A RESPONSE TO GLOBAL CLIMATIC CHANGE

Ｉｎｒｅｃｅｎｔｙｅａｒｓ,ａｔｔｅｎｔｉｏｎｈａｓｂｅｅｎｐａｉｄｔｏｇｌｏｂａｌｃｌｉｍａｔｉｃｃｈａｎｇｅ,ａｎｄｃｅｒｔａｉｎｒｅｓｅａｒｃｈｒｅｓｕｌｔｓｈａｖｅｂｅｅｎｍａｄｅｉｎｖａｒｉｏｕｓｒｅｌａｔｅｄｆｉｅｌｄｓ.Ｔｈｅｃｈａｎｇｅｉｎ ｇｌｏｂａｌｃｌｉｍａｔｅｉｓｍａｉｎｌｙｒｅｐｒｅｓｅｎｔｅｄｂｙｔｈｅｗａｒｍｉｎｇｕｐｏｆｇｌｏｂａｌａｉｒｔｅｍｐｅｒａｔｕｒｅ ,ｆｒｅｑｕｅｎｔｏｃｃｕｒｒｅｎｃｅｏｆＥＮＳＯａｎｄａｂｎｏｒｍａｌｉｔｙｉｎａｔｍｏｓｐｈｅｒｉｃｃｉｒ…     

基于APCS-MLR和PMF模型的赤泥堆场周边耕地土壤重金属污染源解析

为探究重庆某赤泥堆场周边耕地土壤重金属污染特征和来源,分析土壤中8种重金属元素（Cd、Cr、Hg、Ni、Pb、As、Cu和Zn）含量和空间分布特征,利用单因子污染指数法和内梅罗综合污染指数法对土壤重金属污染特征进行评价,并在相关性分析的基础上采用APCS-MLR和PMF模型定量解析重金属来源.结果表明,除土壤Cr外,其他7种重金属元素含量均值均高于重庆市土壤背景值.土壤重金属整体处于中度污染水平,其中Cd、Hg和As为中度污染,Pb、Cu、Ni和Zn为轻度污染.土壤Cr、Ni、Pb、Cu和Zn空间分布格局相似,相互间呈极显著正相关（P < 0.01）;Cd、Hg和As空间分布特征有较大差异,且相互间相关性不显著（P > 0.05）.源解析表明,研究区土壤重金属来源较为复杂,APCS-MLR和PMF模型均能解析出4种相同的污染源,分别为赤泥堆场渗滤排放和自然来源、火力发电排放源、农业活动与自然来源和有色金属冶炼排放源.两种模型源解析结果差异较小,APCS-MLR模型中4种污染源贡献率分别为51.8%、18.0%、15.9%和14.3%,而在PMF模型中分别为45.9%、12.8%、21.5%和19.8%.     

3种人工湿地基质材料对氨氮的吸附特性

对陶粒、石英砂和砾石这3种人工湿地基质材料进行了氨氮（NH₄⁺-N）吸附特性研究.通过扫描电镜和BET比表面积分析仪对材料进行表征分析,发现陶粒表面相比石英砂和砾石更为粗糙,内部孔隙也较发达,陶粒（18.97 m²·g^-1）比表面积高于石英砂和砾石.在纯氨氮溶液和模拟污水厂出水一级B标准的混合溶液中,3种基质对NH₄⁺-N的吸附能力均表现为：陶粒>砾石>石英砂.陶粒对NH₄⁺-N的饱和吸附容量在混合溶液中最大（63.55 mg·g^-1）.陶粒对NH₄⁺-N的吸附过程符合伪二级动力学模型（在纯氨氮溶液中R²为0.99、在混合溶液中R²为0.98）.在纯氨氮溶液中运用Freundlich和Langmuir模型对等温吸附试验结果进行拟合,发现Freundlich模型（R²=0.93）描述陶粒的吸附特性比Langmuir模型更为精确（R²为0.93）,表明陶粒对NH₄⁺-N的吸附为多层吸附.综上所述,陶粒的吸附容量较强,在混合溶液中吸附容量较纯氨氮溶液增大了31%,适用于作为人工湿地基质填料.     

三种磺胺类药物对罗非鱼肝脏组织中谷胱甘肽转移酶（GST）和丙二醛（MDA）的影响

研究磺胺嘧啶（sulfadianzine,SDZ）、磺胺二甲基嘧啶（sulfadimidine,SM2）和磺胺甲基异恶唑（sulfamethoxazole,SMZ）三种典型磺胺类抗生素对罗非鱼（Oreochromis niloticus）肝脏谷胱甘肽转移酶（GST）活性和丙二醛（MDA）含量的响应。采用饲料暴露的给药方式,用磺胺药物浓度为4和40g·kg-1的人工配合饲料喂养试验罗非鱼,对照组投喂不含磺胺药物的空白饲料。暴露时间为7d,每天2次投喂饲料,饲料的日投喂量按鱼体重的3%计,分别在24、72和168h采集肝脏样品待测。结果表明各浓度组GST和MDA分别在暴露后72和24h受到最大程度的诱导,其中GST活性比空白组提高了6.72倍,MDA含量比空白组提高了24.75倍。在4g·kg-1的药物浓度下SM2对GST和MDA有最强诱导,在40g·kg-1的药物浓度下三种药物对罗非鱼GST和MDA诱导效应大小顺序为SDZ〉SMZ〉SM2。GST和MDA在磺胺药物诱导下的响应敏感,适合作为磺胺类药物暴露的生物标记物。     

A study on the short-term effect of particulate matter pollution on hospital visits for asthma in children in Shanghai,China

Environmental Geochemistry and Health - Recently, particulate matter pollution has been worsening, which has been affecting the asthma visits in children. In this study, we assessed the short-term...     

The performance of nitrate-reducing Fe(II) oxidation processes under variable initial Fe/N ratios: The fate of nitrogen and iron species

•Bacterially-mediated coupled N and Fe processes examined in incubation experiments. •NO₃⁻ reduction was considerably inhibited as initial Fe/N ratio increased. •The maximum production of N₂ occurred at an initial Fe/N molar ratio of 6. •Fe minerals produced at Fe/N ratios of 1–2 were mainly easily reducible oxides. The Fe/N ratio is an important control on nitrate-reducing Fe(II) oxidation processes that occur both in the aquatic environment and in wastewater treatment systems. The response of nitrate reduction, Fe oxidation, and mineral production to different initial Fe/N molar ratios in the presence of Paracoccus denitrificans was investigated in 132 h incubation experiments. A decrease in the nitrate reduction rate at 12 h occurred as the Fe/N ratio increased. Accumulated nitrite concentration at Fe/N ratios of 2–10 peaked at 12–84 h, and then decreased continuously to less than 0.1 mmol/L at the end of incubation. N₂O emission was promoted by high Fe/N ratios. Maximum production of N₂ occurred at a Fe/N ratio of 6, in parallel with the highest mole proportion of N₂ resulting from the reduction of nitrate (81.2%). XRD analysis and sequential extraction demonstrated that the main Fe minerals obtained from Fe(II) oxidation were easily reducible oxides such as ferrihydrite (at Fe/N ratios of 1–2), and easily reducible oxides and reducible oxides (at Fe/N ratios of 3–10). The results suggest that Fe/N ratio potentially plays a critical role in regulating N₂, N₂O emissions and Fe mineral formation in nitrate-reducing Fe(II) oxidation processes.     

金盆水库暴雨径流时空演变过程及水质评价

为探究西安金盆水库汛期暴雨径流沿程时空演变过程及库区水质响应,对汛期2019年8月初与9月中旬两场暴雨径流上游河道至库区各断面的水质指标进行持续原位监测,并在垂向上采用单因子污染指数法和综合污染指数法对库区进行水质评价.结果表明：汛期暴雨径流连续不同的来流条件会演变成不同的潜入情况,两次径流初期入流量小,水库潜流均经历全断面径流-底部潜流-间层流的过程,在末期,8月初径流库区间层流位置由初期的545~565 m扩大为535~580 m,9月中旬径流潜流位置由初期540~575 m的间层流演变成575 m以下的底部潜流;连续的入流使库区热分层结构削弱,溶解氧得到补充,同时大量颗粒态污染物汇入库区,营养盐在垂向上表现为中层、底层水体高于表层;单因子污染指数表明径流潜流处总磷和高锰酸盐指数值都有一定的增加,末期均超过地表水Ⅲ类水质标准;综合污染指数表明8月初径流中层水质处于中污染,底层则受厌氧与颗粒沉降的双重影响达到重污染,并且在径流一周后达到峰值,而9月中旬的575 m以下的潜流直接导致中层水体处于重污染,底层由于溶解氧的补充处于中污染;汛期通过泄洪洞的排放与分层取水可以有效地保障供水安全.     

Degradation characteristics and metabolic pathway of 4-nitrophenol by a halotolerant bacterium Arthrobacter sp. CN2

Arthrobacter sp. strain CN2, capable of degrading 4-nitrophenol, was isolated from activated sludge. Degradation of 4-nitrophenol was optimized at pH 7.7, 30?°C, and 0.53% of glucose. Salt tolerance of 4-nitrophenol degradation was as high as 6% (w/v). Several biodegradation intermediates were identified and quantified by high-performance liquid chromatography and mass spectrometry. 4-Nitrocatechol is involved in the degradation of 4-nitrophenol by CN2. Scale-up of 4-nitrophenol degradation was conducted in a bioreactor with different salinity. When the salinity was below 7%, the degradation rate of 4-nitrophenol was above 90% (100 mg L^?1, 3 L).