煤层瓦斯形成的构造地质条件及瓦斯灾害预防

煤盆地的地质构造条件是研究煤层瓦斯形成、富集区分布规律的重要因素。通过对我国含煤盆地的地球动力学背景分析,及储层、盖层中构造裂隙对煤层瓦斯控制因素的研究,阐明了中国大陆是一个由若干陆块和褶皱带组成的复合大陆,煤盆地构造稳定性差,煤层瓦斯赋存条件复杂,这是造成煤层瓦斯突发的根本原因;我国煤盆地大都经历了印支、燕山和喜马拉雅运动,煤盆地受到不同程度的改造,影响了煤层瓦斯的保存条件;弱改造型煤盆地的瓦斯含量较高;强改造型煤盆地瓦斯含量较低。同时指出,面对煤矿瓦斯灾害事故的频繁发生,必须加强对瓦斯事故发生机理等重大理论问题的研究,加强生产、技术人才的培养,坚持“先采气,后开矿”的原则。     

低层通风量及逆温对四川盆地空气质量的影响分析

将四川盆地分为西部平原、中部丘陵和东部山地,采用2014-2020年的ERA5再分析资料、生态环保部官网18个站点的每日AQI监测数据,以及4个探空站的探空数据,利用相关系数和显著性检验的方法,讨论通风量及逆温对空气质量的影响.结果表明,四川盆地空气质量逐年变好,贴地层的通风量等级越大,空气质量越好.总的年均通风量呈先...     

钱塘江南源流域异常水质预测及影响因素分析

基于数据驱动的水质预测模型存在局限性,对突发水质异常事件的预测效果不佳。该研究选取钱塘江南源流域马戍口监测断面为研究对象,综合采用相关性分析方法对水质异常事件的主要影响因素进行分析,明确流域内、外因及土壤条件对水质异常指标的影响程度,探究造成模型局限性的深层原因。结果表明:异常水质的影响因素及其耦合机制复杂多变,异常浊度受降雨量、径流量的直接影响更大,异常高锰酸盐指数与温度、降雨量相关关系更明显,而总磷、总氮的异常变化与相对湿度、降雨量、径流量具有相关关系。研究结果对于提高气候变化背景下的水质预报能力具有重要的参考价值,可为自然流域水污染防治提供科学参考。     

西辽河流域不同土地利用结构硝酸盐氮输出通量模拟

采用土槽模型渗流试验方法,结合土地利用结构现场调查资料研究了西辽河流域不同土地利用结构耕层土壤NO3--N淋溶输出通量的时空变化规律.结果表明,不同土地利用结构NO3--N淋溶输出通量的空间分布规律为农田〔50.23kg/(hm2.a)〕>沙荒地〔12.77kg/(hm2.a)〕>林地〔8.68 kg/(hm2.a)〕>草地〔4.17 kg/(hm2.a)〕,农田和沙荒地对NO3--N输出起源作用,林地和草地起汇作用;西辽河流域沙土区耕层土壤NO3--N输出总量为13.86×104 t/a,不同土地利用结构的NO3--N输出比例为农田(95.31%)>沙荒地(4.69%),农田是西辽河流域氮素营养管理的重点结构;NO3--N输出量夏季(65%)>秋季(25%)>春季(8%)>冬季(2%),夏季是流域氮素营养管理的重点时段;NO3--N淋溶输出通量与土壤硝态氮含量呈极显著正相关.      

Ecotoxicological Assessment of the Impact of Residual Heavy Metals on Soil Nematodes in the Guadiamar River Basin (Southern Spain)

On 25 April 1998, as a consequence of the breaking of a dam containing the tailings of a pyrite mine, a land strip of approximately 43 km in length was covered with a layer of black sludge, containing high levels of heavy metals, along the Guadiamar River Basin (southern Spain). In this investigation we carried out an ecotoxicological assessment (field and laboratory studies) of the impact of residual heavy metals (Cu, Pb, Zn, Ni) on soil nematodes in the impacted riparian zone, two years after the huge mine spillage. Concentrations of residual heavy metals were significantly (P<0.05) higher at the impacted sampling sectors (S-2, S-3, S-4, S-5) than at the unpolluted (reference) sampling sector (S-1). Nickel however exhibited the lowest increases at the impacted sectors. As a consequence, correlation coefficients between concentrations of heavy metals and values of ecological indices were not significant for Ni. In contrast, copper, lead and zinc exhibited significant (P<0.05) negative correlation coefficients with ecological indices, particularly with diversity indices (including the~number of taxa). In addition, the toxicity of Cu and Pb to nematode test species (Aphelenchus avenae and Cephalobus persegnis) during short-term toxicity bioassays was much higher than the toxicity of Zn and Ni. We conclude that residual heavy metals were still influencing adversely the community of soil nematodes in the impacted riparian zone of the Guadiamar River Basin. Cu, Pb and, to a lesser extent, Zn would be major responsible for the observed impact.     

基于SPOT—VGT的黄河流域植被覆盖时空演变

植被是土地覆盖中的最主要部分,是连接土壤、大气和生物等要素的自然“纽带”。植被覆盖动态变化对全球能量循环和物质循环具有重要影响,是全球变化研究的重要内容之一。黄河流域作为我国重要的粮食生产基地,其环境变化直接影响到流域经济的可持续发展。为了快速准确地提取地表植被状况,了解黄河流域生态环境,利用1998—2011年的SPOT-VGT遥感数据,结合地理信息技术,采用均值法和趋势分析法对黄河流域植被NDVI时空分布特征和变化趋势进行了动态监测。结果表明,（1）黄河流域14年NDVI均值的空间分布整体特征是东南部平原、盆地和西部山地植被状况要好于北部地区。其次,黄河流域属于干旱半干旱地区,植被发育主要依赖于水文条件,所以沿黄河干流和支流区域也具有较高的植被NDVI值。（2）黄河流域植被NDVl年均值近14年间整体呈缓慢增长趋势,1998--2000年呈现急剧减少态势,2001--2003年出现了较为快速的增长,2004--2011年又出现了较长时间的连续增长过程。（3）黄河流域植被NDVI基本不变的区域约占研究区总面积的71．13％;植被NDVI轻微改善的区域约占流域总面积的27．30％,且主要分布于流域东南部的盆地、平原和西部的山地、丘陵地区,植被NDVI退化的区域面积约占流域总面积的0．98％。黄河流域自1998年以来,植被NDVI整体在不断提高,生态环境在不断改善。     

基于统计分析的太湖流域某市农业活动区重金属污染特征及来源

对太湖流域某市农业活动区具代表性的14个监测点的土壤(0～10、20～30和50～60 cm)进行采样分析,利用多元统计和地统计学方法,研究了该地区Cd、Pb、Cr和Mn等重金属的空间分布特征及其主要来源. 结果表明,各采样点和各层土壤之间重金属的含量变化较大,变异系数为39.05%～243.52%. 各层土壤中w(Cd)和w(Pb)以及底层土壤中w(Cr)均超过土壤背景值,尤其是w(Cd),表层、中层和底层分别为19.92、17.41和19.97 mg/kg,远高于背景值. 地统计学分析表明,各层土壤中w(Cd)、w(Pb)以及表层土壤中w(Cr)的高值区主要分布在研究区北部,而中层和底层土壤中w(Cr)的高值区主要分布在研究区南部. w(Mn)受自然因素的影响较大,分布较为均匀. 表层、中层和底层土壤中w(Cr)和w(Mn)的相关系数分别为0.715(P<0.01)、0.632(P<0.05)和0.602(P<0.05),w(Pb)与w(Cd)的相关系数分别为0.842(P<0.01)、0.590(P<0.05)和0.874(P<0.01). 主成分分析表明,研究区耕地土壤中w(Mn)主要受地球化学的影响,Cd、Pb和Cr的污染主要来源于工厂所排放的废气、废水,机动车尾气,以及农业活动施入的化肥、农药.      

Land use and land cover dynamics in the Keleta watershed,Awash River basin,Ethiopia

Unprecedented pace and magnitude of land use/land cover (LULC) change in the Ethiopian highlands is a key problem threatening the natural ecosystem and creates vulnerability to an environmental hazard. A combination of remote sensing, field observations and focus group discussions were used to analyze the dynamics and drivers of LULC change from 1985 to 2011 in the Keleta watershed, Ethiopia. Supervised image classification was used to map LULC classes. Focus group discussions and ranking were used to explain the drivers and causes linked to the changes. The result showed rapid expansion of farmland and settlement (36%), shrublands cover shrinking by 50%, while the size of degraded land increased by 45%. Rapid population growth, rainfall variability and soil fertility decline, lack of fuelwood and shortage of cultivation land were ranked as the main causes of LULC change in the watershed according to the focus group discussion. Further effort is needed to improve the creation of new job opportunity, promotion of improved technologies to boost productivity and soil fertility, provide credit facility, extra push on irrigation infrastructure development and soil, water and natural ecosystem conservation practices. Generally, better community-based land resource management will need to ensure sustainable rural livelihoods.     

Elemental composition of bottom-sediments from Pangani river basin,Tanzania: lithogenic and anthropogenic sources

River-bed sediments from the Pangani basin, Tanzania, were characterized for elemental compositions, following contamination risks from rapid expansions of human activities in the area. Samples were collected during two individual seasons and analyzed by high-polarizing beam energy dispersive X-ray fluorescence (EDXRF) for eight major and 14 trace elements. Evaluation of enrichment factors (EFs) was used to investigate the elemental flux and assess the contributions of natural and anthropogenic influences. The abundances of the major elements followed the order Si?>?Al?>?Fe?>?Ca?>?K?>?Ti?>?Mn?>?P, similar to that of the upper earth's crust, and were generally from the weathering of the bed-rock. The high concentrations of typical anthropogenic trace-elements (Cr??1, V??1, Ni??1, Cu??1, La??1) coupled with high EFs (>2) in some locations indicated contamination associated with agricultural and industrial activities. Factor analysis extracted five principal components that contributed to 96.0% of the total observed variance. The results indicated that river-bed sediments of the Pangani basin were influenced to a larger extent by lithogenic sources than anthropogenic impacts.     

太湖流域典型地区农村生活污水中污染物在表层土壤中的削减特征与测算

原位采集太湖流域典型平原河网地区农户化粪池排污口附近的表层土壤及化粪池出水,人工模拟研究区域典型降雨（夏季30 mm·次-1,冬季5mm·次-1）、气温（夏季27℃,冬季5℃）条件以及排污负荷[TN：（2.35±0.06） g·m^-2 ·d^-1,NH4＋-N：（2.08±0.04）g·m^-2· d^-1,TP：（0.21±0.01）g·m^-2·d^-1,COD：（11.14±0.59）g·m^-2·d^-1],并进行室内模拟土柱试验,测算不同季节（夏季和冬季）、不同天气过程（雨前、雨天和雨后）排污口表层土壤对农村生活污水各类污染物的削减率并探讨其削减规律.结果表明：在季节差异上,雨前、雨天和雨后TN削减率均表现为夏季＜冬季（P＜0.05或P＜0.001）,NH4＋-N削减率则均表现为夏季＞冬季（P＜0.01）;雨前和雨后TP削减率表现为夏季＞冬季（P＜0.001）,COD削减率无显著季节性差异;雨天TP和COD削减率则均表现为夏季＜冬季（P＜0.01或P＜0.001）.在天气过程差异上,夏季土壤TN削减率表现为雨后＞雨前＞雨天（P＜0.01）,夏季TP和COD削减率表现为雨前≈雨后＞雨天（P＞0.05,P＜0.01）,而夏季NH4＋-N,冬季TN、NH4＋-N、TP和COD削减率在不同天气过程之间无显著差异（P＞0.05）.据此划分,夏季雨前、雨天和雨后及冬季TN削减率分别为38.5％、-25.0％、46.0％和50.4％,夏季和冬季NH4＋-N削减率分别为91.5％和85.5％,夏季雨天、夏季其余时间及冬季TP削减率分别为63.3％、93.1％和82.7％,夏季雨天及其余时间COD削减率分别为8.2％和66.2％.