Geochemical characteristics of dissolved rare earth elements in acid mine drainage from abandoned high-As coal mining area,southwestern China

Acid mine drainage (AMD) represents a major source of water pollution in the small watershed of Xingren coalfield in southwestern Guizhou Province. A detailed geochemical study was performed to investigate the origin, distribution, and migration of REEs by determining the concentrations of REEs and major solutes in AMD samples, concentrations of REEs in coal, bedrocks, and sediment samples, and modeling REEs aqueous species. The results highlighted that all water samples collected in the mining area are identified as low pH, high concentrations of Fe, Al, SO₄ ^2? and distinctive As and REEs. The spatial distributions of REEs showed a peak in where it is nearby the location of discharging of AMD, and then decrease significantly with distance away from the mining areas. Lots of labile REEs have an origin of coal and bedrocks, whereas the acid produced by the oxidation of pyrite is a prerequisite to cause the dissolution of coal and bedrocks, and then promoting REEs release in AMD. The North American Shale Composite (NASC)-normalized REE patterns of coal and bedrocks are enriched in light REEs (LREEs) and middle REEs (MREEs) relative to heavy REEs (HREEs). Contrary to these solid samples, AMD samples showed slightly enrichment of MREEs compared with LREEs and HREEs. This behavior implied that REEs probably fractionate during acid leaching, dissolution of bedrocks, and subsequent transport, so that the MREEs is primarily enriched in AMD samples. Calculation of REEs inorganic species for AMD demonstrated that sulfate complexes (Ln(SO₄)⁺and Ln(SO₄)₂ ^?) predominate in these species, accounting for most of proportions for the total REEs species. The high concentrations of dissolved SO₄ ^2? and low pH play a decisive role in controlling the presence of REEs in AMD, as these conditions are necessary for formation of stable REEs-sulfate complexes in current study. The migration and transportation of REEs in AMD are more likely constrained by adsorption and co-precipitation of Fe-Al hydroxides/hydroxysulfate. In addition, the MREEs is preferentially captured by poorly crystalline Fe-Al hydroxides/hydroxysulfate, which favors that sediments also preserve NASC-normalized patterns with MREEs enrichment in the stream.

     

我国长江流域中三角区域大气污染物排放特征研究

中三角区域已经是我国第四个国家级城市群,也将成为我国经济增长的"第四极"。在经济发展的同时,更需要以节能减排、资源环境等为重点,以实现经济建设与生态文明"双可持续"的协同发展。本文以二氧化硫、氮氧化物、烟(粉)尘为主要大气污染物,对我国中三角区域大气污染物排放进行了详细的分析,并与京津冀、长三角、珠三角、"三区十群"等进行了多方位比较。结果表明,2013年中三角区域二氧化硫排放量为151.7万t,其中工业二氧化硫排放量为140.1万t;氮氧化物排放量为147.2万t,其中工业氮氧化物排放量为93.6万t;烟(粉)尘排放量为81.8万t,其中工业烟(粉)尘排放量为71.4万t。中三角区域二氧化硫、氮氧化物、烟(粉)尘排放量均位于"四极"的第三。中三角区域二氧化硫、氮氧化物、烟(粉)尘单位GDP排放强度分别为25.03t/亿元、24.29 t/亿元、13.50 t/亿元,分别位于"四极"的第一、第二、第二。同时,本文还从经济发展模式、产业结构调整、煤炭消费方式等方面对我国中三角等经济"四极"提出了相关建议。     

地表水环境质量综合评价方法研究与应用进展

水质评价是目前水环境质量管理的重要支撑,水质综合评价方法已经逐渐由断面评价向流域综合评价进行转变与突破。该文对目前的断面水质评价方法进行了归类综述,并且对流域水质综合评价方法及其在各个国家流域的应用进行了重点评述。分析认为中国在流域评价中所使用的"断面比例法"不够准确,缺乏污染物时空分析以及生物评价等问题,并据此提出了未来的研究方向,为未来地表水质评价方法的提升以及水环境管理的完善提供科学的参考依据和建议。     

长湖流域水质时空分布特征及影响因子

利用2009—2014年长湖5个水质监测点数据,采用时间序列法分析了长湖水质的时间变化规律,采用相关性分析法,分析了流域水污染的影响因子。结果表明:在时间上,长湖水污染物质量浓度季节变化明显,COD、TN、NH3-N均为7、9月较低,1、3月较高,丰水期水质好于枯水期。入湖地区TP质量浓度7月达最高值,且7月份入湖地区的桥河口、关沮口的NH3-N、TN含量稍高于5月。空间上,西北部入湖地区水质劣于湖心及东南部出湖地区。工业、生活等点源污水,以耕地为主的农业非点源以及天然降水量和径流量是影响水质的主要因素,入湖排污量、降水量和径流量与长湖水质呈显著相关关系(P0.05)。     

降水中甲酸、乙酸和草酸的离子色谱法测定及样品保存研究

甲酸、乙酸和草酸是降水中有机酸的主要成分。研究选用离子色谱法同时测定降水中的甲酸、乙酸和草酸,并对降水样品中3种有机酸的保存条件进行了研究。优化后的色谱条件为4. 0 mmol/L Na_2CO_3和1. 2 mmol/L NaHCO_3混合淋洗液,淋洗液流速为1. 0 m L/min,进样体积为200μL,电导池温度为30℃,柱温为室温。甲酸、乙酸和草酸的检出限分别为0. 002、0. 005、0. 005 mg/L,实际降水样品测定时平行样的相对标准偏差为1. 4%～12%,加标回收率为95%～118%。样品采集后需尽快用0. 45μm聚醚砜微孔滤膜过滤,4℃以下冷藏密封保存,2 d内测定。若用氢氧化钠溶液调节p H至8～10,样品可保存7 d。     

Association of exposure to multiple metals with papillary thyroid cancer risk in China

Papillary thyroid cancer (PTC) has inflicted huge threats to the health of mankind. Metal pollution could be a potential risk factor of PTC occurrence, but existing relevant epidemiological researches are limited. The current case-control study was designed to evaluate the relationships between exposure to multiple metals and the risk of PTC. A total of 262 histologically confirmed PTC cases were recruited. Age- and gender-matched controls were enrolled at the same time. Urine samples were used as biomarkers to reflect the levels of environmental exposure to 13 metals. Conditional logistic regression models were adopted to assess the potential association. Single-metal and multi-metal models were separately conducted to evaluate the impacts of single and co-exposure to 13 metals. The increased concentration of urinary Cd, Cu, Fe, and Pb quartiles was found significant correlated with PTC risk. We also found the decreased trends of urinary Se, Zn, and Mn quartiles with the ORs for PTC. These dose-response associations between Pb and PTC were observed in the single-metal model and remained significant in the multi-metal model (OR_25-50th=1.39, OR_50-75th=3.32, OR_>75th=7.62, p for trend <0.001). Our study suggested that PTC was positively associated with urinary levels of Cd, Cu, Fe, Pb, and inversely associated with Se, Zn, and Mn. Targeted public health policies should be made to improve the environment and the recognition of potential risk factors. These findings need additional studies to confirm in other population.

     

基于工业生态化建设的工业园区环境管理研究

工业园区是产业集聚的载体,是区域经济发展的引擎。工业园区同时又是污染产生排放集中地,我国工业园区在发展过程中随着经济总量扩大、资源和能源消耗的增加,出现了大量的环境问题,阻碍了园区的可持续发展。工业园区的环境管理可以从园区层面出发解决污染问题,这是个既复杂又重要的工作。本文在分析工业园区发展历程的基础上揭示了目前工业园区存在的环境问题,以及管理方面存在的缺陷和不足,发现总体上园区环境管理水平较差。工业生态化建设为进行合理的园区环境管理提供了一个契机,本文针对我国工业园区的发展现状及发展趋势,提出基于工业生态化建设的工业园区环境管理的对策:1提升生态工业的意识,鼓励公众参与;2确立生态化建设思想,以生态化建设促进环境管理效率的提升;3加强工业生态化建设相关政策法规、规划的完善和实施;4构建工业生态化建设信息服务平台,以生态化建设来实现工业园区科学的环境管理。     

Effect of Soybean Cultivation on Soil Collembola Community in Marshland of Sanjiang Plain,China

The Sanjiang Plain, the largest inland freshwater marshland in China, was extensive reclaimed into agricultural land. To assess the effects of marshland reclamation on Collembola, we investigated collembolan communities in a chronosequence of soybean plantations (2, 15, and 25 years) in Sanjiang marshland, Northeastern China. We found that: 1) the densities and species richness of Collembola were promoted after short-term (2 years) cultivation of soybean, but significantly decreased after medium-term cultivation (15 years); 2) the densities of epi-edaphic Collembola increased while the densities of hemi-edaphic Collembola decreased as the elongation of soybean cultivation; 3) compared with S0, two species of Collembola appeared while five species disappeared in S25. The changes of plant communities and the soil traits were supposed to be the key factors affecting the composition of soil Collembola. We thus suggest that original marshland should be saved for preserving high diversity and densities of Collembola in the Sanjiang Plain.

     

水杨酸法检测水质氨氮的改进方法

该氨氮检测方法是对水杨酸分光光度法的改进,通过将50 g/L的水杨酸改为150 g/L的水杨酸钠,将有效氯为3. 5 g/L的次氯酸钠溶液改为5 g/L的二氯异氰尿酸钠溶液,增加了检测试剂的稳定性和贮存时间,同时将氨氮测定上限从1 mg/L提高至2. 5 mg/L,并将显色时间从60 min优化为30 min,使得此方法更为便捷。该方法的氨氮标准曲线线性关系良好,相关系数为0. 999 6,准确性和精密度高,加标回收率良好,适用于不同类型水质中氨氮的检测。