Phthalic acid esters (PAEs) in workplace and house dust from Vietnam: concentrations,profiles, emission sources,and exposure risk

Environmental Science and Pollution Research - The occurrence of nine phthalic acid esters (PAEs) were determined in indoor dust samples collected from vehicle repair shops, waste processing...     

污灌地重金属镉污染的伴矿景天修复试验研究

针对城郊污灌地土壤重金属Cd污染,利用超富积植物伴矿景天(Sedum plumbizincicola)进行Cd污染土壤的植物修复正交试验研究,以探讨Cd污染土壤的最优田间修复措施.研究表明:修复植物-伴矿景天茎叶中Cd的含量均值达到8.80 mg/kg,约为玉米茎叶的58倍,芹菜茎叶的135倍;土壤-植物系统中Cd的迁移量由高到低的顺序为:伴矿景天＞玉米＞芹菜;对正交试验中伴矿景天的Cd提取率进行极差分析,最佳试验因素结果为:因素A:种植方式为扦插10株/m2、因素C种植模式为单作、因素B调控剂硫粉施用量为2 g/m2,试验结果中此方案伴矿景天对土壤中Cd的提取率达到8.49％,是9个处理组中最高的,与极差分析结果一致.实际应用中,本文推荐选择A1C3B3方案(种植方式为扦插10株/m2、因素C种植模式为与玉米间作、因素B调控剂硫粉施用量为6 g/m2)作为伴矿景天植物修复的最优田间农艺措施方案,以达到边修复边生产的农业土壤修复模式.     

广东省臭氧污染特征及其来源解析研究

使用广东省近年大范围长期连续臭氧观测数据分析了珠三角与广东省的臭氧污染特征,并使用NAQPMS模型研究了广东省与典型城市不同季节的臭氧来源情况.结果表明:2014—2016年广东省的臭氧污染局部在改善.珠三角的臭氧浓度水平总体高于粤东西北地区,广东省臭氧总体上呈现出珠三角中南部和粤东东部部分地区较高、粤西污染相对较轻的分布态势.广东省的臭氧夏秋季浓度较高,冬春季浓度较低.广东省臭氧主要来源于本地排放,夏季占比为57%,其余季节约占40%,臭氧的跨省输送特征明显.珠三角西南部春夏季臭氧本地贡献约为50%,但秋冬季仅占19%~28%.若要减轻广东的臭氧污染,建议实施臭氧消峰行动,即在夏秋季节严控珠三角地区的臭氧前体物排放,特别是珠三角中部广州、佛山与东莞等城市的排放要重点控制.同时,强化粤东西北地区与周边省份的协同减排.     

Urban Land-banking Planning： A New Instrument to Regulate Urban Land Supply-demand of Nanjing City

It is the major purpose of the paper to present the urban land-banking planning and its functions of promoting the urban land-banking system and land use administration. The urban land-banking system has the potential attribute of acting as an irreplaceable role in urban land administration, but its unexpected function-deviation has impacted its implementation effect in China. A few city governments are attempting to deal with the problem by the urban land-banking planning which is expected to contribute to the extension of urban function, optimization of urban patterns, promotion of urban core competitiveness and overall construction of the urban value chain. In this paper, we primarily discuss the necessity, functions, purposes and main contents of the urban land-banking planning. Subsequently, the implementing situation of the urban land-banking system in Nanjing is analyzed, including its integrated mode, spatio-temporal quantitative distribution and main characteristics. Finally, the background and targets including total, compositions, space, and regulation points are gradually introduced to present the Nanjing land-banking planning version 2.     

Effects of nematicides on population of pratylenchus penetrans and growth of flue‐cured tobacco

Abstract

Field studies were conducted on loamy sand at Tamscu farm, Delhi, Ontario, to compare the spring ridge application of Telone C17 at 73 and 101L/ha, Vorlex at 28 and 84L/ha, Vorlex CP at 50L/ha, and spring rotovated application of oxamyl at 2.24kg/ha respectively for the control of Pratylenchus penetrans (Cobb) Filip. and Stek., and for effects on the yield and quality of fluecured tobacco. Experiments were conducted on May 9 in an area that had been summer fallowed in previous year. Nematode densities of P. penetrans per kilogram of soil were lower than other treatments and controls with Telone C17 at 73 L/ha treated plots on May 24; with Vorlex at 28 L on June 7; Vorlex at 84 L on May 24 and on June 7; Vorlex CP on June 7, and with oxamyl on Sept. 6. The nematode population counts per gram dry weight of root were lower with Telone C17 at 73 L/ha on June 7, July 5, and at 101 L/ha on July 5; with Vorlex at 28 L/ha on June 7, July 5, and Sept. 6; with Vorlex at 84 L/ha on June 7, June 21, July 5 and Sept. 6, and with Vorlex CP at 50 L/ha on June 7, July 5 and Sept. 6 in the ridged soil. The population was lower with oxamyl on June 21, July 5, and Sept. 6 in the rotovated soils. There was no difference in the agronomic data on yield, indices of grade, crop and maturity, while tobacco plant height and dry weight in the ridged fanning were greater with treatments of Vorlex at 84 L and Vorlex CP at 50 L/ha. The ridged farming had greater yield of tobacco than rotovated farming. Vorlex was the most effective of all nematicides used in the experiment.     

Photocatalytic oxidation of propoxur in aqueous titanium dioxide suspensions

Abstract

The photocatalytic oxidation of propoxur, a nitrogen‐containing pesticide, has been investigated using aqueous TiO₂ suspensions as catalyst in this study. The operating variables considered in the study were initial pH, temperature, [H₂O₂] and TiO₂ loading. Results showed that 1 g/l of TiO₂ was the optimum dosage for oxidizing propoxur in this system. Hydrogen peroxide can increase the oxidation rate with increasing its initial concentration. There was no obvious difference in the rate of propoxur oxidation at the initial pH of 4, 6 and 9, and the final pHs of reaction solutions were around 5.5. However, propoxur degraded slower at initial pH 2, and the pH did not vary during the period of photocatalytic reaction. The photocatalytic oxidation of propoxur using TiO₂ suspensions as the photocatalyst was reaction‐controlled as indicated by the activation energy.     

Contamination by arsenic and other trace elements in tube-well water and its risk assessment to humans in Hanoi, Vietnam

Concentrations of As and other trace elements and their association were examined in groundwater (n = 25) and human hair (n = 59) collected at Gia Lam District and Thanh Tri District, suburban areas of Hanoi, Vietnam, in September 2001. Concentrations of As in the groundwater ranged from <0.10 to 330 microg/l, with about 40% of these exceeding WHO drinking water guideline of 10 microg/l. Also, 76% and 12% of groundwater samples had higher concentrations of Mn and Ba than WHO drinking water guidelines, respectively. Arsenic concentrations in hair of residents in Gia Lam and Thanh Tri Districts (range 0.088-2.77 microg/g dry wt.) were lower than those in other As-contaminated areas of the world, but were higher than those of people in non-contaminated areas. Concentrations of As and Mn in hair of some individuals from the Gia Lam and Thanh Tri Districts exceeded the level associated with their toxicity and, therefore, a potential health risk of As and Mn is a concern for the people consuming the contaminated water in this area. Cumulative As exposure was estimated to be lower than the threshold levels at the present, which might explain the absence of manifestations of chronic As poisoning and arsenicosis in the residents of Gia Lam and Thanh Tri Districts. To our knowledge, this study revealed for the first time that the residents are exposed not only to As but also Mn and Ba from groundwater in the Red River Delta, Vietnam.     

螺旋群锚在岩土介质中极限抗拔力的试验分析及工程应用

通过室内模型试验 ,初步探讨了在砂土中当螺旋群锚的间距改变时 ,其受力性能的变化 ;通过试验及分析 ;提出了计算螺旋群锚在不同间距时的极限承载力公式 ;同时对螺旋锚在工程安全中的应用进行了分析     

如何加强车间安全管理工作

车闻安全管理是企业安全管理的重要环节,用怎样的措施手段和方法来强化车间安全管理呢? 正确理解党的安全方针“安全第一,预防为主”这八字方针是一个整体,在工作中不能分开讲,也不能分开理解。安全第一是搞好生产的基础和前提条件,预防为主是搞好安全生产的实际行动、有力措施和有效手段。如果只讲安全第一,不讲预防为主,会产生安全工作挂在嘴上、写在纸上、赔上墙、没有落实在行动上的形式主义。     

Evaluating the Applicability of a Two‐dimensional Flow Model of a Highly Heterogeneous Domain to Flow and Environmental Management

Two‐dimensional simulation of highly heterogeneous domains, especially those with disparate length scales, roughness conditions, and geometries, often leads to challenges such as long computation times and numerical instability. Simulation of challenging domains is often needed to guide flood management and environmental regulation agencies in operation and potential domain modifications. This work evaluates the ability of a two‐dimensional unsteady hydrodynamic model to represent long‐duration transient flows over a domain with highly heterogeneous roughness, geometric characteristics, and length scales through bed roughness representation. The domain includes 13 km of Cache Creek and the 14.5 km² Cache Creek Settling Basin, which traps both sediment and mercury. Calibration under different bed roughness methods, validation, and modeling results of bathymetric modification scenarios are presented. The modeling approach's performance supports its application as a tool for management of similar domains, such as settling basins, leveed floodplains, and reservoirs. Accurate representation of flow dynamics can also inform environmental management that involves transport of sediments, nutrients, and heavy metals. This study found that a two‐dimensional unsteady flow model can accurately represent long‐duration transient flow in a large settling basin with highly heterogeneous characteristics without parsing of the domain or flow events simulated.