Biosorption of Cu^2＋ and Zn^2＋ by raw and autoclaved Rocella phycopsis

The behavior of Cu2+ and Zn2+ biosorption onto raw and modified Roccella phycopsis from aqueous solutions was studied. Modification process was applied by autoclavation at 121°C for 30 min. The effcts of pH, initial metal concentration and biosorbent dosage were investigated. The maximum Cu2+ biosorption was achieved at pH 5.0 and the maximum biosorption capacities of 31.5 and 37.8 mg/g were recorded for raw and modified biosorbent, respectively. In the case of Zn2+ biosorption, maximum biosorption capacities were obtained at pH 4.0 as 29.1 and 35.3 mg/g for raw and modified biosorbent, respectively. Biosorption of Zn2+ and Cu2+ on all form of R. phycopsis increased much quickly with increasing initial metal concentrations from 10 to 100 mg/L. After modification process, probable changes in the surface polarity of raw and modified R. phycopsis were investigated by contact angle measurements. As expected, R. phycopsis has a polar surface and shows a highest contact angle with water, while after autoclavation water contact angle of R. phycopsis was significantly decreased from 47.5° to 34.4°.     

Validation of a conductometric bienzyme biosensor for the detection of proteins as marker of organic matter in river samples

This article describes a conductometric bi-layer based bienzyme biosensor for the detection of proteins as a marker of organic matter in rivers. Proteins were chosen to be used as indicators of urban pollution. The working mechanism of the bienzyme biosensor is based on the enzymatic hydrolysis of proteins into several fractions (peptides and amino acids), which results in a local conductivity change depending of the concentration of proteins. In this work, we began with the optimization of biosensor response using bovine serum albumin (BSA) as standard protein. For this objective seven enzymatic biosensors were prepared: four enzymatic sensors with only one layer of enzyme (proteinase K, trypsin, pronase or protease X) and three other enzymatic sensors with two layers (first layer: membrane containing proteinase K; second layer: one of the three other enzymes: trypsin, pronase or protease X). The biosensors were obtained through the deposition of enzymatic layers and the cross-linking process between enzymes and BSA in saturated glutaraldehyde vapour. The response of the various biosensors, described previously, were compared with the values of total organic carbon (TOC), and those of organic nitrogen (Norg), as determined by the laboratory accredits (CEMAGREF of Lyon) using the traditional method of analysis (NF EN 1484, infrared spectroscopy) and (NF EN 25663, mineralization/colorimetry assay) respectively for each water sample obtained from di erent sites in Lyon (France). The linear correlations obtained with the response of the seven biosensors showed the most important indices of correlations for the biosensor with two enzymatic layers: proteinase K + pronase (pkp). The optimum conditions for the preparation of the pkp biosensor increased the sensitivity and gave a limit of quantification of 0.583 g/L for TOC and 0.218 g/L for Norg in water samples. This sensor shows good reproducibility (2.28%), a capacity to be used at temperatures range 10– 30°C (depending on the season) and moreover a long lifetime (5 weeks).     

中国大陆省级无意产生的五氯苯和六氯苯多源大气排放清单

基于技术分类方法构建了动态排放因子数据库,再采用排放因子法,自下而上构建了1960～2019年中国大陆省级无意产生的五氯苯和六氯苯的多源大气排放清单,并探究其时空分布特征.研究结果显示,五氯苯的最大排放源是含氯化学品生产,而六氯苯的最大排放源则是金属冶炼;五氯苯和六氯苯的排放密度均表现为东部地区高于西部地区的特征.从1960～2019年,五氯苯和六氯苯的排放量从1277.9,81.2kg分别上升至11862.3,439.7kg,但排放强度(单位GDP的排放量)却从869.3,55.2g/亿元分别下降至12.0,0.4g/亿元.     

韩国1999年工伤事故死亡人数

韩国 1 999年工伤事故死亡人数达 2 2 91人 ,比1 998年增加 79人 ,上升 3.57%。然而 ,其中有 2 2 1 2人死于工业事故。死亡人数的上升部分源于经济的复苏 ,但考虑到从 1 998年开始 ,工人的总人数已经减少的事实 ,月平均工作时间的增加所造成的超负荷工作和压力是引起死亡人数上     

Effect of land use and land cover change on soil erosion and the spatio-temporal variation in Liupan Mountain Region, southern Ningxia, China

The Liupan Mountains are located in the southern Ningxia Hui Autonomous Region of China, that forms an important divide between landforms and biogeographic regions. The populated part of the Liupan Mountain Region has suffered tremendous ecological damage over time due to population pressure, excessive demand and inappropriate use of agricultural land resources. To present the relationship between land use/cover change and spatio-temporal variation of soil erosion, data sets of land use between the late 1980s and 2000 were obtained from Landsat Thematic Mapper (TM) imagery, and spatial models were used to characterize landscape and soil erosion conditions. Also, soil erosion in response to land use and land cover change were quantified and analyzed using data from geographical information systems and remote sensing. Soil erosion by water was the dominant mode of soil loss, while soil erosion by wind was only present on a relatively small area. The degree of soil erosion was classified into five severity classes: slight, light, moderate, severe, and very severe. Soil erosion in the Liupan Mountain Region increased between the late 1980s and 2000, both in terms of acreage and severity. Moderate, severe, and very severe eroded areas accounted for 54.86% of the total land area. The lightly eroded area decreased, while the moderately eroded area increased by 368817 ha (22%) followed by severe erosion with 146552 ha (8.8%), and very severe erosion by 97067.6 ha (5.8%). Soil loss on sloping cropland increased with slope gradients. About 90% of the cropland was located on slopes less than 15°. Most of the increase in soil erosion on cropland was due to conversion of steep slopes to cropland and degradation of grassland and increased activities. Soil erosion was severe on grassland with a moderate or low grass cover and on dry land. Human activities, cultivation on steep slopes, and overgrazing of pastures were the main reasons for the increase in erosion severity.     

电位溶出法测铅

在环境监测中测定水、土、大气、植物、食品、饮料、污水等样品中的Cu、Pb、Zn、Cd、Mo、Fe,常用原子吸收分光光度法、双硫腙法,但上述方法分别存在着一次性投资大和试剂消耗多,操作复杂的问题。监测低含量的Cu、Pb、Zn、Cd,曾推广过极谱阳极溶出法,并列为规范方法试行。但是该方法由于对操作条件要求苛刻,难以掌握,而使人们对电化学分析产生偏见。MP-1型微分电位溶出分析仪以微分电位溶出为主要功能,辅之极谱分析,省去了过去极谱分析方法中所存在的通氮气、清洗、富集、静止、以人工秒表控制时间的繁杂过程,解决了样品重现性差的问题…     

乌鲁木齐市大气环境质量关键污染因子及变化趋势的研究

利用灰色系统原理,对乌鲁木齐市大气环境原始监测数据进行了分析,找出影响大气环境质量关键因子并判断污染趋势;在此基础上对乌鲁木齐市2009年、2015年大气环境质量中关键因子及污染趋势进行了预测,取得了良好效果。     

酶联免疫吸附法测定水中异丙隆

建立了测定水中异丙隆的酶联免疫吸附法。灵敏度0.97μg/L，最低检出限0.03μg/L16种取代脲类除草剂的交叉反应率低于2.2%。水样可不经分离提取直接测定。10%甲醇、2%乙腈和2%乙醇不影响测定。比较了11种与异丙隆结构相近的半抗原的活性。     

Mercury in an ultraoligotrophic North Patagonian Andean lake (Argentina): Concentration patterns in di erent components of the water column

The deep, ultraoligotrophic piedmont lakes of Northern Patagonia (Argentina) are located in pristine and barely impacted areas, along a wide latitudinal range. Several studies have reported moderate to high total mercury (Hg) concentrations and contrasting methylmercury (CH3Hg+) production in di erent lake compartments. Sources of Hg for western Patagonian terrestrial and aquatic ecosystems are still not clear; while point sources can be ruled out and atmospheric deposition is a plausible source, along with contribution from active volcanic areas of the Andes. In this investigation, we reported a noticeably seasonal, spatial (between lake branches), and vertical (between water column strata) heterogeneity in the total Hg concentrations found in the pelagic zone of Lake Moreno. Sterile water samples taken in a depth profile of the lake showed moderate to high concentrations of CH3Hg+ in autumn with a decreasing trend with depth. Our results indicated that Hg is largely allocated in the plankton fraction between 10–53 m; which dominated within the euphotic (epilimnetic) zone of the lake due to the high densities attained by two species of the dinoflagellate Gymnodinium. The 53–200 m planktonic size fraction (comprising rotifers, ciliates and immature stages of crustaceans) and the > 200 m fraction (calanoid copepods and cladocerans) were found to bear strikingly lower total Hg concentrations, suggesting that the magnification of Hg at the planktonic consumer level is negligible.