Carbon disulfide at a Chinese viscose factory external and internal exposure assessment

This article presents the results of carbon disulfide exposure measurements in a Chinese viscose rayon factory. The objectives of the study were to identify the external exposure levels at a large factory and to investigate the 2-thiothiazolidine-4-carboxylic acid (TTCA) concentrations in the urine of the subjects who were exposed to carbon disulfide in the working place atmosphere. The metabolism of carbon disulfide in the exposed subjects was also studied in order to demonstrate the best points in time for the internal exposure sampling. The measurement of the amount of personal exposure to carbon disulfide in the air of the workplace was performed by GC-FPD; the presence of TTCA in the workers urine was analyzed by use of a modified HPLC method. The kinetics of TTCA excretion was studied by analyses at different time-points both during and after exposure to carbon disulfide in the subjects. A total of 155 personal samples were obtained. The carbon disulfide concentration in the staple viscose hall was 13.72 +/- 1.12 mg m-3 in terms of the geometric mean +/- geometric standard deviation, and was 20.05 +/- 1.33 mg m-3 in the filament spinning hall. The TTCA values in the subjects who worked in the staple spinning hall were 1.18 +/- 0.43 mg g-1 creatinine and 1.07 +/- 0.38 mg g-1 creatinine for subjects working in the filament spinning hall. The best time for TTCA sampling is at the end of the working shift, the TTCA excretion was stable for a period of 4-12 h after exposure of the subjects to the carbon disulfide. It might be that the Chinese have different anthropometric characteristics; a sampling bias may therefore appear among different races.     

Analysis of metabolic changes in Trichoderma asperellum TJ01 at different fermentation time-points by LC-QQQ-MS

Trichoderma spp. are among the most widely recognized biocontrol fungi used to inhibit pathogens and promote plant growth. These functions are related to primary and secondary metabolites. This study investigated the different metabolites in Trichoderma asperellum TJ01 cultured for 24 and 72?h using liquid chromatography with triple-quadrupole mass spectrometry. Compared to the 24?h culture of T. asperellum TJ01, the 72?h culture with amino acid metabolism tended to decrease while sugar and lipid metabolisms tended to increase. Furthermore, the 72?h culture had a higher proportion of upregulated flavonoids, in combination with a higher proportion of downregulated alkaloids, and equal proportions of upregulated and downregulated polyphenols and hormones. This study also identified a few valuable medicinal substances such as trigonelline and 5-hydroxytryptophan in T. asperellum TJ01 fermentation cultures.     

Manganese uptake and accumulation by the hyperaccumulator plant Phytolacca acinosa Roxb. (Phytolaccaceae)

The perennial herb Phytolacca acinosa Roxb. (Phytolaccaceae), which occurs in Southern China, has been found to be a new manganese hyperaccumulator by means of field surveys on Mn-rich soils and by glasshouse experiments. This species not only has remarkable tolerance to Mn but also has extraordinary uptake and accumulation capacity for this element. The maximum Mn concentration in the leaf dry matter was 19,300 microg/g on Xiangtan Mn tailings wastelands, with a mean of 14,480 microg/g. Under nutrient solution culture conditions, P. acinosa could grow normally with Mn supplied at a concentration of 8000 micromol/l, although with less biomass than in control samples supplied with Mn at 5 micromol/l. Manganese concentration in the shoots increased with increasing external Mn levels, but the total mass of Mn accumulated in the shoots first increased and then decreased. At an Mn concentration of 5000 micromol/l in the culture solution, the Mn accumulation in the shoot dry matter was highest (258 mg/plant). However, the Mn concentration in the leaves reached its highest value (36,380 microg/g) at an Mn supply level of 12,000 micromol/l. These results confirm that P. acinosa is an Mn hyperaccumulator which grows rapidly, has substantial biomass, wide distribution and a broad ecological amplitude. This species provides a new plant resource for exploring the mechanism of Mn hyperaccumulation, and has potential for use in the phytoremediation of Mn-contaminated soils.     

生物质炭对华北平原4种典型土壤N2O排放的影响

生物质炭作为一种新型的土壤改良剂,在降低土壤温室气体排放方面发挥着重要作用.为明确生物质炭对冬小麦苗期土壤N_2O排放的影响,以华北平原的4种典型土壤(水稻土、砂姜黑土、褐土和潮土)为研究对象,进行田间试验,设置了4个处理:对照(CK)、单施化肥(NPK)、单施生物质炭(BC)和化肥与生物质炭配施(NPK+BC).结果表明,单施化肥显著增加了4种土壤N_2O排放,与对照相比,水稻土、砂姜黑土、褐土和潮土N_2O排放分别增加了314%、116%、240%和282%.添加生物质炭对华北平原4种土壤N_2O排放影响存在差异,与CK相比,单施生物质炭水稻土、褐土N_2O排放显著增加了72. 4%和50. 9%,而砂姜黑土和潮土BC与CK处理无显著差异.与NPK相比,生物质炭与化肥配施显著降低了4种土壤N_2O排放.添加生物质炭提高了4种土壤pH,其中,初始pH最低的水稻土,受生物质炭影响较显著,施肥则降低了4种土壤pH.砂姜黑土、褐土和潮土施肥处理N_2O排放通量均与铵态氮含量呈显著正相关,水稻土和砂姜黑土单施生物质炭处理N_2O排放通量与硝态氮含量呈显著正相关.     

浙江某垃圾焚烧厂周边土壤中稀土元素分布特征及潜在生态风险评价

采用电感耦合等离子体质谱仪测定了浙江某垃圾焚烧厂周边表层土壤样品中镧、铈、镨、钕、钇等15种稀土元素的浓度。利用统计学方法分析稀土元素分布特征,并评价土壤稀土元素的潜在生态风险水平。结果表明,该垃圾焚烧厂周边表层土壤中稀土元素平均浓度范围为0.49—84.51 mg·kg⁻¹,总稀土元素浓度范围为231.21—259.47 mg·kg⁻¹,均高于土壤背景值,而焚烧厂尾气中的稀土元素浓度达到385.73 mg·kg⁻¹。稀土元素的浓度增量分析结果表明,稀土元素的浓度增量趋势与风频分布趋势相似,浓度增量越大的区域其风频越大,两者的相关性系数达到0.928。潜在生态风险指数显示,该垃圾焚烧厂周边土壤中稀土元素的潜在生态风险评价指数值范围为16.67—17.21,风频较小的上风向区域和平行风向1区域处于低生态风险水平,风频较大的下风向区域和平行风向2区域处于中等生态风险水平。垃圾焚烧厂周边土壤中稀土元素累积很可能受到了焚烧厂尾气排放的影响,随着焚烧尾气的持续排放,后期生态风险可能还会增加。     

水体及沉积物微塑料污染对近海养殖海区的生态风险

微塑料在全球海洋水体及沉积物中广泛存在,然而关于近海养殖海区的微塑料污染特征鲜有报道,本研究调查了中国近海养殖海区茅尾海水体和沉积物中微塑料的分布特征并初步对其微塑料污染进行风险评估. 结果表明,茅尾海区域广泛分布着微塑料,茅尾海水体中微塑料的平均丰度为（2.01±1.23） n·m⁻³,泡沫（60.1%）是主要的类型. 沉积物中的微塑料平均丰度为（22.4±19.6）n·kg⁻¹,薄片（50%—100%）在采样点中占主要部分. 茅尾海水体、沉积物中的微塑料粒径都以1—5 mm为主（33.3%—100%）,水体和沉积物中的微塑料主要来自钦江的输入、旅游活动以及海水养殖活动. 通过风险评估模型初步得出,茅尾海区域微塑料的污染水平属于中等偏低水平,水体中微塑料整体污染风险等级显著高于沉积物,生态风险等级分别属于Ⅲ级（较高风险）和Ⅱ级（较低风险）. 风险指数最高的点位于茅尾海入海河流钦江入海处,达到了Ⅳ级（高风险）,各沉积物采样点的风险等级主要集中在Ⅰ—Ⅱ级,属于较低风险. 危害评分高的聚合物聚丙烯腈（Polyacrylonitrile,PAN）是水体中微塑料污染风险的重要来源.     

一体化生物除磷脱氮技术--反硝化除磷

介绍了一种高效、节能的生物除磷脱氮技术-反硝化除磷。通过与传统生物除磷技术的比较,总结反硝化除磷的机理、影响因素并探讨它在脱氮好氧颗粒污泥中的应用。     

SPATIAL ANALYSIS AND EUTROPHICATION ASSESSMENT FOR CHLOROPHYLL a IN TAIHU LAKE

Spatial structure analysis and kriging analysis have been identified to be useful tools in illustrating the spatial patterns of variables. Taihu Lake is one of the largest fresh water lakes in China, and has suffered serious eutrophication in recent years due to the rapid economic development and growing environmental pollution in the Taihu Catchment. In this paper, spatial structural analysis, kriging interpolation and eutrophication assessment were carried out for chlorophyll a in the lake. Studies show that spherical model could be applied to fit all experimental variograms. Positive nuggets were observed for three directions except NE–SW direction. The variograms show some anisotropy with anisotropic ratio falling within 1.76. The spatial structural patterns of chlorophyll a in the lake were affected by factors such as distribution of pollution sources, water flow and wind. Two-dimensional ordinary block kriging was applied for interpolation process. An eutrophication assessment map was also made based on a water-quality evaluation standard. Results show that the content of chlorophyll a in Taihu Lake was quite high. The whole lake has suffered serious eutrophication. However, the eutrophic situation varied in space. Higher contents of chlorophyll a appeared mainly in the northern part of the lake.     

Effects of Topographical Heterogeneity and Dispersal Limitation on Species Turnover in a Temperate Mountane Ecosystem: a Case Study in the Henan Province,China

Species turnover patterns can be inconsistent due to differences in the dispersal ability of different growth forms. Here, species of trees, shrubs, herbs, and bryophytes in the Xiaoqinling National Nature Reserve in China were analyzed to determine patterns of species turnover along an elevation and spatial gradient. Variance partitioning was used to assess the relative contribution of topographic heterogeneity and dispersal limitation to species turnover. Our results suggest that the effect of dispersal limitation is more important than topographic heterogeneity on species turnover in temperate mountane ecosystems in the study area. Dispersal limitation has a greater effect on trees species turnover than on shrubs, herbs or bryophytes species turnover.     

响应面法优化石油降解菌性能的研究

从延长油田石油污染土壤中筛选出4株能以原油为唯一碳源生长的细菌单菌株,鉴定其优势菌株YC-2为枯草芽孢杆菌;利用响应面法进行实验设计,选定培养温度、pH值、氮磷比以及盐度为影响因素,对原油含量为0.5%的培养基进行YC-2菌株降解工艺优化,得到了原油降解率与4种因素之间的非线性回归方程,确定了降解原油的最优工艺条件:培养温度28℃;pH值6.5,氮磷比5.2:1,盐度0.45%。在最优条件下,预测降解率为53.9%,实验验证值为52.5%,结果显示,建立的模型具有较高的精度。