Did the ecological engineering have a great impact on the land use change?

Overuse of land resources has increasingly contributed to environmental crises in China. To mitigate widespread land degradation, actions have been taken to maintain and restore the ecological environment through efforts such as ecological engineering. By analyzing trends in land use, the impact and effectiveness of ecological engineering can be determined. In this study, such changes in Huanjiang County in China were considered. In the early 1990s, an eco-immigration policy and “returning farmland to forest program” were implemented in the county, drastically impacting land use. Land use/land cover changes were detected and analyzed using remote sensing data recorded over 4 years (1995, 2000, 2005, and 2010). Land transfer flow and the rate of land use change elucidated the extent of changes, while nuclear density analysis indicated spatial agglomeration. The results indicate that, over a period of 15 years, farmland area increased, while forest area decreased initially before subsequently increasing. From 1995 to 2000, the highest transfer flow was observed in the grassland to farmland conversion (79.34%). From 2000 to 2005, the transfer flow of conversions was the highest for forest to farmland (56.79%). Land use changes were not prominent from 2005 to 2010. Direct drivers of land use change exert obvious impacts on land use, and indirect drivers impact direct drivers that are then channeled through direct anthropogenic drivers (e.g., land use policies). We found that ecological engineering has a very significant impact on land use change, and that impact varies from region to region.     

硅烷化改性沸石对重金属离子的吸附性能

制得一种用于重金属废水处理的新型硅烷化改性沸石吸附剂,成本低、效果显著且稳定。通过对改性沸石表征,分析了改性对沸石结构的影响。结果表明,改性一定程度降低了原沸石的晶体特征,但基本上保持了其结构组成;硅烷化改性成功地在沸石上接枝了氨基。对硅烷化沸石的特性研究,得出硅烷化沸石对Ni2+、Cu2+、Zn2+和Pb2+吸附最佳投加量为1、1、1.6和0.6 g/L,且此时对4种离子的去除率也较好;吸附动力学研究得出,其吸附过程可用二级动力学方程较好地拟合;吸附达到平衡时,4种金属离子的平衡吸附量分别为11.23、17.41、15.45和59.42 mg/g;硅烷化沸石对金属离子的吸附行为更符合Langmuir模型,为化学吸附;在酸性条件下(pH=2～6),硅烷化沸石仍保持一定的吸附能力,具有一定的耐酸性。     

Occurrence and photochemical degradation of 17alpha-ethinylestradiol in Acushnet River Estuary

17alpha-Ethinylestradiol (EE2), a major constituent of common contraceptive pills, and three other estrogenic hormones, estrone (E1), 17beta-estradiol (E2) and mestranol (MeEE2) have been determined in Acushnet River Estuary seawater using a GC-MS technique. Among three estrogenic compounds detected, EE2 has the highest concentration, up to 4.7 ng/l, at which EE2 may affect lobster and other fish abundance in the coastal seawater due to its high biological activity on fish feminization. Two natural estrogenic hormones, E1 and E2 have also been found in the estuary at concentrations up to 1.2 ng/l and 0.83 ng/l, respectively. Although EE2 is persistent to microbial degradation, it can undergo a rapid photodegradation in estuarine seawater under natural sunlight irradiation, with a half-life of less than 1.5 days in spring sunny days.     

渗滤液的反渗透浓缩液回灌技术应用

以宜昌、宁国、蒙城垃圾填埋场为例,介绍了碟管式反渗透(DTRO)——浓缩液回灌工艺,研究发现:浓缩液回灌方式应根据垃圾填埋场的地理特征和业主的具体要求来确定。山谷型填埋场可以采用石笼回灌法,施工简单,成本较低,另外也可采用两层生物滤化床方式,成本稍高,但效果较好;平原型填埋场宜采用两层生物滤化床方式,而采用石笼回灌法容易出现短流现象。浓缩液回灌对渗滤液电导率无明显影响,不会影响后续反渗透系统的正常运行。     

氧化还原修复重金属污染土壤的文献计量学分析

基于Web of Science和中国知网(CNKI)的数据源,选择对应数据库、设定年限,检索相关文献和专利,运用文献计量学方法,并借助Origin、Excel等绘图制表工具对数据结果进行了统计、分析和对比,比较直观地展现出重金属污染土壤氧化还原修复技术的总体情况、国内外发展现状和趋势、国内外发展差距,并从关键词的发展演替角度分析研究热点与方向,为氧化还原修复技术相关学科发展与研究等提供决策参考。     

基于MOD16的安徽省地表蒸散量时空变化特征

安徽省是我国的农业大省,其水资源的管理和利用直接影响到农业的可持续发展,分析安徽省的蒸散量变化,对水资源的科学配置和合理利用有着重要的意义。基于MOD16蒸散量产品,利用均值、标准差、偏差法、趋势分析法以及空间变异等方法,分析安徽省近15 a地表蒸散量年际、年内时空变化特征,和不同土地利用类型下蒸散量的差异性变化特征。研究表明：（1）2000~2014年间安徽省多年平均蒸散量为694.9 mm,波动范围为647.5~730.5 mm,年际变化呈现下降趋势;并具有较强的空间分异性规律,整体上呈现南高北低趋势,各市多年蒸散量均值差异显著,其中黄山的蒸散量最高（844.1 mm）,宿州最低（603.7 mm）。（2）安徽省年内各月间的蒸散量呈现先增加后减少的“单峰型”趋势,具有明显的季节差异,表现为夏季(304.17 mm)＞春季(167.56 mm)＞秋季(150.41 mm)＞冬季(73.92 mm);但各市的年内蒸散量变化趋势表现不同,淮河以南整体呈现“单峰型”趋势,淮河以北则呈现典型的“双峰型”趋势。（3）安徽省不同土地利用类型的蒸散量差异明显,其年均蒸散量按照“林地＞草地＞未利用地>耕地＞城镇用地”的顺序递减。 关键词： MOD16; 安徽省; 蒸散量; 时空分布; 土地利用     

改性膨润土对水体中多环芳烃的吸附

改性膨润土被广泛地应用于吸附水体中重金属离子和有机污染物,但关于改性膨润土吸附水体中多环芳烃混合物的动力学研究鲜见报道。利用十二烷基三甲溴化铵和十二烷基磺酸钠对膨润土进行改性,并将之应用于吸附水体中萘、蒽、菲和芘4种多环芳烃,考察了吸附剂投加量、时间和温度等条件对吸附效果的影响。实验结果表明,在25℃、吸附时间40 min、起始浓度为1.25 mg/mL、改性膨润土的投加量为4 g/L的条件下,该吸附剂对萘、蒽、菲和芘的吸附率分别为99.1%、99.6%、98.7%和98.9%。改性膨润土对水体中4种多环芳烃的吸附机理服从准二级动力学方程,该吸附剂吸附等温线服从Langmuir方程。     

铁负载阴离子交换树脂高效除磷研究

针对污水处理生化出水高磷酸盐浓度对水体富营养化影响的问题,采用阴离子交换树脂(AER)为基质材料,利用树脂上—NH2官能团中的N原子与Fe3+发生配位聚合,制备了除磷聚合配位交换吸附剂(Fe—PLE)。并采用Langmuir和Freundlich等温吸附方程对Fe—PLE和原AER进行了比较,发现Fe—PLE更加趋向化学吸附类型,且Fe—PLE最大吸附容量达到93.05 mg/g,比AER提高了47.98%。通过SEM、EDS、FT-IR及TGA对吸附前后Fe—PLE和AER的表征比较,认为通过配位作用形成Fe—O配位键是Fe—PLE的可溶性无机磷吸附效率提高的主要原因。通过静态吸附实验考察了吸附时间、pH和竞争性阴离子对AER和Fe—PLE吸附的影响,结果显示,Fe—PLE吸附平衡时间为1.5 h,比AER稍高;2种吸附填料都在pH 7.0时效率最高,AER的磷吸附效率对pH较为敏感,Fe—PLE能够在相对较宽的pH范围内保持高去除率;竞争性阴离子对AER磷吸附的负面影响较大,而Fe—PLE依靠其Fe—O的配位作用具有一定的抗干扰能力。通过4次循环再生实验,Fe—PLE表现出良好再生能力的同时磷有较高的回收利用率。     

基于AHP对生态脆弱性的灰色综合评价方法——以湖南省临湘市为例

为了对临湘市的实际生态脆弱性程度做出客观正确的评价,以便对该地区的社会经济持续发展提出科学依据,选取评价指标,构建指标体系并通过层次分析法确定各指标的权重;通过基于三角白化权函数的灰色评价法对各层次指标进行评价和分析并得到综合评价结果。     

浅谈大气污染物对人体健康的影响

论述了几种主要大气污染物的性质、来源及其作用机理,并探讨了大气污染物对人体健康的影响及危害。