Changes in hourly precipitation may explain the sharp reduction of discharge in the middle reach of the Yellow River after 2000

The Hekou-Longmen reach, together with local floods, is the main source area for coarse sedimentations into the Yellow River. When total rainfall slightly increased in the area, discharge dramatically decreased by 40%–70% after the year of 2000, and attracting extensive attention in the context of global climate change. High temporal resolution precipitation (timescales between 1 and 4 h) data from the June to September period from 270 rain gauges over the past three decades was mined in order to help explain the phenomenon. Each rainfall event was classified as light/moderate rain, large rain, heavy rain or rainstorm by the event’s rainfall amount, and further classified as low intensity rain, medium intensity rain and high intensity rain by the event’s rainfall intensity. The Mann-Kendall trend test was applied to detect the presence and significance of monotonic trends, and to find the change points in the mean and variance of the precipitation characteristics series, including the amount, intensity, frequency and duration of each rainfall category. Results show that although the total amount of precipitation has slightly increased, the average rainfall intensity has significantly decreased. The larger change happened in light/moderate rain events and low/medium intensity rain events, and the intensity changes have a great extent occurred around the threshold of Non-Runoff Rainfall regime, which was proposed for the approximate calculation of initial losses. Changes in rainfall distribution between different classes of the Runoff Rainfall regime in the 2000s could lead to 0.9 mm less runoff depth (17.3% of the total reduction) than the 1980–1999 period. The study indicates that changes in hourly precipitation may be responsible for the sharp reduction of discharge.     

Status and fuzzy comprehensive assessment of metals and arsenic contamination in farmland soils along the Yanghe River,China

Concentrations of metals and arsenic in farmland soils along the Yanghe River, upstream of Guanting Reservoir, were evaluated using fuzzy comprehensive assessment (FCA). FCA is an emerging methodology for assessing environmental status based on fuzzy logic which can model linguistic data and represent chaotic conditions. The ratio of concentrations of metals and arsenic (As) in surface soils of farmland along the Yanghe River to the corresponding reference values decreased in the order Cd>Zn>Cr>Ni>Pb>Cu>As. Based on the FCA, 86% of surface soils along the Yanghe River were classified as grade C, which is suitable for forestry with a greater absorption capacity, suggesting that most farmland along the Yanghe River has to be abandoned as farmland. In order to improve the quality of soil along the Yanghe River and avoid degeneration of water quality in the river and the Guanting Reservoir, remediation of farmland soils along the river is suggested.     

镉污染对红壤和潮土微生物的生态毒理效应

以土壤微生物生物量碳(Cmic)、土壤酶活性及微生物多样性为微生物学指标,以0.01mol·L-1CaCl2作为Cd有效态提取剂,以江西红壤和天津潮土为供试土壤,在室内25℃连续培养28d的条件下探讨了外源Cd对土壤微生物的生态毒理效应。结果表明:1)不同培养时间潮土CaCl2提取态Cd含量均显著低于红壤,潮土微生物受到Cd的抑制作用也明显小于红壤。2)各微生物指标的敏感性不同,并受土壤类型和培养时间的影响,其中,脱氢酶的敏感性强于脲酶,微生物功能多样性指标中BiologEco板上每孔的平均吸光值(AWCD)的敏感性强于Shannon指数;Cmic、脲酶、脱氢酶、AWCD和Shannon指数均在红壤中更为敏感。选取的5个微生物指标对Cd污染都有良好的响应,均可作为Cd污染土壤微生物生态毒理实验中的测试指标。在土壤酶指标中,可优先选取脱氢酶作为测试指标。3)Cd对Cmic、土壤酶、微生物功能多样性的抑制作用存在时间效应。14dCd对Cmic的抑制作用大于28d,而对脲酶和脱氢酶的抑制作用小于28d。建议Cd污染土壤微生物生态毒理实验中将培养时间设置为28d或适当延长。4)28d时,红壤中Cd对Cmic、脱氢酶、脲酶、AWCD、Shannon指数的EC10分别为1.31、0.26、0.93、0.08、22.71mg·kg-1,而在潮土中分别为1.97、0.69、13.12、0.09、>200mg·kg-1。     

Energy and Economic flow in homegardens in Subtropical Yunnan,SW China: A case study on Sanjia village

We studied the energy and economic flow of six types of homegardens in Sanjia village, SW China. Our study showed that the energy input of six types of homegardens averaged 99.11-175.65 x 10¹⁰J/ha, the energy output was 102.30-159.83 x 10¹⁰J/ha and the ratio of input/output ranged between 1:0.880-1:1.416. The ratios of input to output of home-gardens that prioritized cultivation of crops were higher than for homegardens that prioritized animal husbandry or other economic activities. The economic ratio of input/ output of six types of homegardens varied between 1:0.997-1:1.376 and the economic output ranged between 2480.0-10131.5 RMB/yr. We concluded that the homegarden systems of Sanjia village are high in the input and output of energy and cash flow, and can provide a basis for designing models of farm economy in rural subtropical areas.     

绍兴市富营养化水源水中有机物特性研究

采用超滤法对绍兴富营养化水源水中有机物进行了分子量的测定,继而考察了不同分子量区间的有机物对色度,紫外吸收的影响,并与淮河（蚌埠段）水及密云水库水中的有机物特性作了比较,发现密云水库水以小分子有机物为主,分子量小３０００的有机物占总ＢＯＣ的９６．７％,而绍兴水及淮河水（蚌埠段）中有机物相对分子质量分布相对较为均匀,分子量大于３０００的有机物占总ＤＯＣ的比例分别为２８．３７％和３８．２８％,水中有机     

生物水解（酸化）法处理高浓度洁霉素废水的降解机理研究

在应用生物水解（酸化）法处理高浓度洁霉素生产废水中试试验中,着重研究水解（酸化）反应中起主要作用的微生物菌群及其降解效率。同时采用GPC（凝胶渗透色谱）、GC/MS（色谱一质谱）等分析手段对水解（酸化）反应过程中有机物形态变化进行研究。结果表明,在水解（酸化）反应中起主要作用的有埃希氏菌属、发酵单胞菌属、气单胞菌属、变形杆菌属、柠檬酸杆菌属等。同时,水解（酸化）反应具有将洁霉素废水中的大分子有机物降解为小分子有机物的作用,可提高废水的可生化性。     

深圳市电磁辐射环境现状及对策研究

深圳市电磁辐射环境现状复杂,为了掌握深圳市电磁辐射环境现状,加强电磁辐射环境管理,通过对深圳市"十一五"期间电磁辐射污染特征及原因分析,有针对性地提出了加强电磁辐射环境管理的对策建议。     

Fine particulate matter (PM2.5/PM1.0) in Beijing, China: Variations and chemical compositions as well as sources

Particulate matter (i.e., PM_1.0 and PM_2.5), considered as the key atmospheric pollutants, exerts negative effects on visibility, global climate, and human health by associated chemical compositions. However, our understanding of PM and its chemical compositions in Beijing under the current atmospheric environment is still not complete after witnessing marked alleviation during 2013–2017. Continuous measurements can be crucial for further air quality improvement by better characterizing PM pollution and chemical compositions in Beijing. Here, we conducted simultaneous measurements on PM in Beijing during 2018–2019. Results indicate that annual mean PM_1.0 and PM_2.5 concentrations were 35.49 ± 18.61 µg/m³ and 66.58 ± 60.17 µg/m³, showing a positive response to emission controls. The contribution of sulfate, nitrate, and ammonium (SNA) played an enhanced role with elevated PM loading and acted as the main contributors to pollution episodes. Discrepancies observed among chemical species between PM_1.0 and PM_2.5 in spring suggest that sand particles trend to accumulate in the range of 1–2.5 µm. Pollution episodes occurred accompanied with southerly clusters and high formation of SNA by heterogeneous reactions in summer and winter, respectively. Results from positive matrix factorization (PMF) combined with potential source contribution function (PSCF) models showed that potential areas were seasonal dependent, secondary and vehicular sources became much more important compared with previous studies in Beijing. Our study presented a continuous investigation on PM and sources origins in Beijing, which provides a better understanding for further emission control as well as a reference for other cities in developing countries.     

电渗析技术在浓盐水回收项目的应用研究

电渗析技术作为一种新兴的膜分离技术,因高效率低能耗、对预处理要求低、对分离组分选择性高、原水回收率高、环境友好等优点,在国内外各行业获得广泛应用.江苏华晖环保科技有限公司改进了电渗析工艺参数,并在贵州开磷(集团)有限责任公司进行了推广应用,大大降低了出水中Cl-和Ca2+浓度,电导率由数千us/cm降到200 us/cm以下.电渗析技术可节约水资源,社会、环境、经济效益显著,对企业实现真正的“零排放”具有巨大的推动力.     

抗锶放线菌的分子鉴定及对Sr~(2+)的吸附效果和初步吸附机理分析

从大亚湾核电站附近水体中分离筛选出一株抗锶放线菌(编号YF-64),研究了该菌株在不同环境参数条件下对锶的吸附效果和初步机理,通过形态和16S rDNA序列相结合的方法对菌株进行了分类鉴定,采用红外光谱(FT-IR)分析技术对菌株吸附前后进行表征,探讨其吸附机制。结果表明,抗锶菌株隶属于天蓝黄链霉菌(基因序列登录号:JF901702),菌株对Sr~(2+)具有较强的吸附效果,根据数据显示,当接触时间为50 min,pH值为6,Sr~(2+)初始浓度为50 mg/L,摇床转速为120 r/min时,该菌株的吸附效果达到最佳为44.29 mg/g;FT-IR结果显示,JF901702菌株对Sr~(2+)的吸附主要是由细胞壁上的羟基,次甲基,羰基起主要吸附作用。由此可知,JF901702菌株可作为经济、高效、环境友好的生物吸附材料进行废水重金属处理。