Sorption of hydrophobic pesticides on a Mediterranean soil affected by wastewater, dissolved organic matter and salts

Irrigation with treated wastewaters as an alternative in countries with severe water shortage may influence the sorption of pesticides and their environmental effects, as wastewater contains higher concentrations of suspended and dissolved organic matter and inorganic compounds than freshwater. We have examined the sorption behaviour of three highly hydrophobic pesticides (the herbicide pendimethalin and the insecticides α-cypermethrin and deltamethrin) on a Mediterranean agricultural soil using the batch equilibration method. We considered wastewater, extracts from urban sewage sludge with different dissolved organic carbon contents, and inorganic salt solutions, using Milli Q water as a control. All pesticides were strongly retained by soil although some sorption occurred on the walls of the laboratory containers, especially when wastewater and inorganic salt solutions were used. The calculation of distribution constants by measuring pesticide concentrations in soil and solution indicated that pendimethalin sorption was not affected whereas α-cypermethrin and deltamethrin retention were significantly enhanced (ca. 5 and 2 times, respectively) when wastewater or salt solutions were employed. We therefore conclude that the increased sorption of the two pesticides caused by wastewater cannot be only the result of its dissolved organic carbon content, but also of the simultaneous presence of inorganic salts in the solution.     

Utilization of waste foundry sand (WFS) in concrete manufacturing

Due to ever increasing quantities of waste materials and industrial by-products, solid waste management is the prime concern in the world. Scarcity of land-filling space and because of its ever increasing cost, recycling and utilization of industrial by-products and waste materials has become an attractive proposition to disposal. There are several types of industrial by-products and waste materials. The utilization of such materials in concrete not only makes it economical, but also helps in reducing disposal concerns. One such industrial by-product is waste foundry sand (SFS). Waste foundry sand is a by-product of ferrous and nonferrous metal casting industries. Foundries successfully recycle and reuse the sand many times in a foundry. When the sand can no longer be reused in the foundry, it is removed from the foundry and is termed as waste foundry sand.Published literature has shown that WFS could be used in manufacturing Controlled Low-Strength Materials (CLSM) and concrete. This paper presents an overview of some of the research published on the use of WFS in concrete. Effect of WFS on concrete properties such as compressive strength, splitting tensile strength, modulus of elasticity, freezing-thawing resistance, and shrinkage are presented.     

煤层干式钻进粉尘扩散规律的研究

针对煤层干式钻进过程中粉尘污染严重的问题,分别对新庄孜矿c13煤层及10煤层干式钻进粉尘的分散度和煤的硬度进行测定,分析对比2煤层钻进时粉尘在3 m/s风速下的浓度分布情况;并针对C13煤层,在1.5 m/s,2.3 m/s和3 m/s的风速下测定粉尘浓度分布情况.根据粉尘浓度的实测数据,分析煤层干式钻进粉尘扩散规律....     

粤东凤凰山茶区土壤氟化学形态特征及其影响因素

采用连续化学提取法对粤东凤凰山茶区12个较大型茶园共60份土壤样品氟的5种化学形态分布进行研究.结果发现,土壤中氟的5种化学形态分布的规律为残余态〉〉铁锰结合态〉有机态〉水溶态〉可交换态.水溶态氟含量与可交换态氟含量、残余态氟含量及总氟含量呈显著正相关性,而铁锰结合态含量与有机束缚态之间呈显著正相关性,残余态与总氟之间...     

微量钒的分光光度测定方法研究进展

综述分光光度法测定试样中微量钒,并对各种方法的测量条件、特点以及应用范围作了较为详尽的论述和介绍。     

Evaluating weather effects on interannual variation in net ecosystem productivity of a coastal temperate forest landscape: A model intercomparison

Forest productivity is strongly affected by seasonal weather patterns and by natural or anthropogenic disturbances. However weather effects on forest productivity are not currently represented in inventory-based models such as CBM-CFS3 used in national forest C accounting programs. To evaluate different approaches to modelling these effects, a model intercomparison was conducted among CBM-CFS3 and four process models (ecosys, CN-CLASS, Can-IBIS and 3PG) over a 2500 ha landscape in the Oyster River (OR) area of British Columbia, Canada. The process models used local weather data to simulate net primary productivity (NPP), net ecosystem productivity (NEP) and net biome productivity (NBP) from 1920 to 2005. Other inputs used by the process and inventory models were generated from soil, land cover and disturbance records. During a period of intense disturbance from 1928 to 1943, simulated NBP diverged considerably among the models. This divergence was attributed to differences among models in the sizes of detrital and humus C stocks in different soil layers to which a uniform set of soil C transformation coefficients was applied during disturbances. After the disturbance period, divergence in modelled NBP among models was much smaller, and attributed mainly to differences in simulated NPP caused by different approaches to modelling weather effects on productivity. In spite of these differences, age-detrended variation in annual NPP and NEP of closed canopy forest stands was negatively correlated with mean daily maximum air temperature during July-September (T_amax) in all process models (R² = 0.4-0.6), indicating that these correlations were robust. The negative correlation between T_amax and NEP was attributed to different processes in different models, which were tested by comparing CO₂ fluxes from these models with those measured by eddy covariance (EC) under contrasting air temperatures (T_a). The general agreement in sensitivity of annual NPP to T_amax among the process models led to the development of a generalized algorithm for weather effects on NPP of coastal temperate coniferous forests for use in inventory-based models such as CBM-CFS3: NPP′ = NPP − 57.1 (T_amax − 18.6), where NPP and NPP′ are the current and temperature-adjusted annual NPP estimates from the inventory-based model, 18.6 is the long-term mean daily maximum air temperature during July-September, and T_amax is the mean value for the current year. Our analysis indicated that the sensitivity of NPP to T_amax was nonlinear, so that this algorithm should not be extrapolated beyond the conditions of this study. However the process-based methodology to estimate weather effects on NPP and NEP developed in this study is widely applicable to other forest types and may be adopted for other inventory based forest carbon cycle models.     

LAKE WATER COLOR: COMPARISON OF DIRECT OBSERVATIONS WITH UNDERWATER SPECTRAL IRRADIANCE1

ABSTRACT: The water color in 14 lakes of diverse optical character has been computed from near-surface upwelling irradiance spectra recorded by a submersible spectroradiometer. In these lakes the hues corresponding to irradiance spectra are in reasonable agreement with Munsell hue matches obtained directly by observation in the field. The simple field technique for hue matching using the Munsell standards was broadly validated by this spectroradiometric study. The technique is recommended for further study by limnologists and water resource managers as a potential additional tool for characterizing waters.     

典型铁路工程水土流失情况调查研究

在我国水力侵蚀亚区内选取几条施工中铁路进行现场水力侵蚀实验调查,对铁路施工期水力侵蚀情况调查和研究,并在我国5个水力侵蚀亚区内的铁路施工期水力侵蚀进行人工降雨试验和侵蚀沟调查,研究结果得出5个侵蚀亚区内各铁路工程类型施工期水土流失等级、加速侵蚀因子和侵蚀模数。结论表明,交通工程边坡水力侵蚀程度受施工工程特点影响非常明显,新型构造物的形成将引发严重的土壤侵蚀现象。     

Variability of the Integrated Biochemical Index in Fish Exposed to Technogenic Water of Mining and Ore-Processing Works

The hazard presented to aquatic animals by technogenic waters from mining and ore processing works, with an abnormally high potassium content and alkaline pH, was studied in experiments with fish using the integrated biochemical index (IBI) allowing an aggregate estimation of changes in the animal organism. The results showed that the IBI value directly depends on the extent of technogenic pollution, as well as on the species and age of fish.