Dieldrin uptake by vegetable crops grown in contaminated soils

The aim of these trials was to study the distribution of dieldrin in soil and its translocation to roots and the aerial parts of vegetable crops grown in greenhouses and fields. The main objectives were to characterize dieldrin accumulation in plant tissues in relation to the levels of soil contamination; uptake capability among plants belonging to different species, varieties and cultivars. The presence of the contaminant was quantified by gas chromatography-electron capture detector (GC-ECD) and confirmed by gas chromatography-mass spectrometer (GC-MS). The results showed a translocation of residues in cucurbitaceous fruits and flowers confirming that zucchini, cucumber and melon are crops with high uptake capability. The maximum level of dieldrin residue at 0.01 mg/kg was found to be a threshold value to safeguard the quality production of cucurbits. Tomato, lettuce and celery were identified as substitute crops to grow in contaminated fields.     

Divergent toxicity of parathion in two freshwater invertebrates, orconectes rusticus and viviparus malleatus

The toxicity of parathion and its metabolite paraoxon was examined in the crayfish Orconectes rusticus and the snail Viviparus malleatus and attempts were made to relate this to parathion uptake and metabolism. The crayfish was found to be very susceptible with all animals tested dying at 0.1 ppb of parathion in 48 hours. The snail was resistant to exposure to 1000 ppm. The absence of lethality even to injected (50 mg/kg) parathion and paraoxon suggests an innate lack of susceptibility. Metabolism of the compounds could not be detected in vitro or in vivo in either species.     

Solar fuels: vision and concepts

The world needs new, environmentally friendly and renewable fuels to allow an exchange from fossil fuels. The fuel must be made from cheap and 'endless' resources that are available everywhere. The new research area on solar fuels, which are made from solar energy and water, aims to meet this demand. The paper discusses why we need a solar fuel and why electricity is not enough; it proposes solar energy as the major renewable energy source to feed from. The present research strategies, involving direct, semi-direct and indirect approaches to produce solar fuels, are overviewed.     

Solar Fuels: Vision and Concepts

The world needs new, environmentally friendly and renewable fuels to allow an exchange from fossil fuels. The fuel must be made from cheap and ‘endless’ resources that are available everywhere. The new research area on solar fuels, which are made from solar energy and water, aims to meet this demand. The paper discusses why we need a solar fuel and why electricity is not enough; it proposes solar energy as the major renewable energy source to feed from. The present research strategies, involving direct, semi-direct and indirect approaches to produce solar fuels, are overviewed.     

基于神经网络的活性污泥系统建模及其控制

针对松江污水厂污水处理活性污泥系统,采用神经网络技术进行建模试验研究,在对实际运行数据剔除异常数据后,将样本数据随机分成训练样本、检验样本和测试样本.用试凑法确定合理的神经网络隐层节点数,用检验样本实时监控训练过程从而避免"过训练"现象,用多次改变网络初始连接权值求得全局极小点,从而建立了泛化能力较好的基于神经网络的活性污泥系统数学模型.利用建立的神经网络模型,对活性污泥系统运行情况的仿真与控制进行了分析研究.示例研究表明:神经网络技术能较好地应用于活性污泥系统的建模与控制,有很好的理论与实践意义.     

Dry deposition and internal circulation of nitrogen,sulphur and base cations to a coniferous forest

The dry deposition of sulphur, nitrogen and base cations to a spruce stand was estimated during a five year period using a surrogate surface resembling needles, throughfall and bulk deposition measurements. The deposition was calculated from the ratio between the deposition of an ion and sodium on the surrogate surface and the net throughfall of sodium to the forest. The dry deposition represented a large fraction of the total atmospheric input of base cations. For Na⁺, Mg²⁺, Ca²⁺, and K⁺ they were 66, 67, 53 and 42%, respectively. The internal circulation was 95% of non-marine net throughfall fro K⁺ and 76% for Ca²⁺. The dry deposition of SO₂ to the canopies regulates the internal circulation of Ca²⁺. The dry deposition of SO₂ to the canopies regulates the internal circulation of Ca²⁺. The dry depositions of ammonium and nitrate are close to the net throughfall of Kjeldahl-N and nitrate, respectively. The obtained deposition velocities are comparable to other studies. The calculated dry deposition of ammonium was compared to the net throughfall of ammonium at three nearby forest stands receiving different ammonium amounts on the soils. No correlation to nitrogen level was found, but most ammonium was lost and converted to organic nitrogen in the canopies of the wettest forest stand.     

Toxic heavy metal contamination and risk assessment of street dust in small towns of Shanghai suburban area, China

The aims of this paper were to quantify the heavy metal concentrations in street dust of small towns in Shanghai suburban area compared with those in urban area, and examine their seasonal and spatial variations, and to assess their risks to water environment and local populations. Street dust samples were collected from three small towns and urban area in Shanghai in different seasons. Levels of heavy metals were determined by atomic adsorption spectrophotometer analyzer. The method of potential ecological risk index and the health risk assessment model were used to evaluate the potential risks to water bodies and local residents, respectively. The mean metal concentrations in street dust of small towns were far above soil background values but still lower than those in the urban area. No significant seasonal change was observed except for Cr, Ni, and Zn concentrations. Higher metal concentrations tended to be located in central area of towns and township roads. The integrated metal contamination was high and posed a strong potential ecological risk. Children had greater health risk than adults. The carcinogenic risk probabilities were under the acceptable level. The hazard index values to children were close to the safe level. Street dust from the studied area has been contaminated by heavy metals. The contamination of these elements is related more to the pollution source than seasonal change. The combination of the six metals may threaten the water environment and has non-cancer health risk to children, but not to adults.     

Pb and Cd binding to natural freshwater biofilms developed at different pH: the important role of culture pH

The effects of solution pH on adsorption of trace metals to different types of natural aquatic solid materials have been studied extensively, but few studies have been carried out to investigate the effect of pH at which the solid materials were formed on the adsorption. The purpose of present study is to examine this effect of culture pH on metal adsorption to natural freshwater biofilms. The adsorption of Pb and Cd to biofilms which were developed at different culture pH values (ranging from 6.5 to 9.0) was measured at the same adsorption pH value (6.5). The culture pH had considerable effects on both composition and metal adsorption ability of the biofilms. Higher culture pH usually promoted the accumulation of organic material and Fe oxides in the biofilms. The culture pH also affected the quantity and species of algae in the biofilms. The adsorption of Pb and Cd to the biofilms generally increased with the increase of culture pH. This increase was minor at lower pH range and significant at higher pH range and was more remarkable for Cd adsorption than for Pb adsorption. The notable contribution of organic material to the adsorption at higher culture pH values was also observed. The profound impacts of culture pH on adsorption behavior of biofilms mainly resulted from the variation of total contents of the biofilm components and were also affected by the alteration of composition and properties of the components.     

Does tradeoff between financial and social indicators matters in environmental consideration: evidence from G7 region

The study tries to discover the impact of financial and social indicators’ growth towards environmental considerations to understand the drivers of economic growth and carbon dioxide emissions change in G7 countries. The DEA-like composite index has been used to examine the tradeoff between financial and social indicator matters in environmental consideration by using a multi-objective goal programming approach. The data from 2008 to 2018 is collected from G-7 countries. The results from the DEA-like composite index reveals that there is a mixed condition of environmental sustainability in G-7 countries where the USA is performing better and Japan is performing worse among the set of other countries. The further result shows that the energy and fiscal indicators help to decrease the dangerous gas emissions. Divergent to that, the human and financial index positively contributes to greenhouse gas emissions. Fostering sustainable development is essential to successfully reduce emissions, meet established objectives, and ensure steady development. The study provides valuable information for policymakers.

     

射流曝气的气液两相流的数值模拟

射流曝气在活性污泥处理方法中起着重要的作用。采用数值模拟的方法研究自吸式单级单喷射流器中的气液两相流动状况，通过对不同长径比和喷嘴面积比的射流曝气器模型的气液两相流的计算，定量分析长径比和喷嘴面积比对射流曝气器流场和空气与工作介质流量比的影响，为进一步设计开发新型高效的射流曝气器提供参考。     

Annual input fluxes of heavy metals in agricultural soil of Hainan Island,China

The accumulation of heavy metals in farmland has become an important issue related to food security and environmental risk. The annual inputs of heavy metals (As, Cd, Hg, Pb, Cr, Cu, and Zn) to agricultural soil for a full year in Hainan Island have been studied. Three fluxes through the cultivated horizon were considered: (1) atmospheric depositions, (2) fertilization, and (3) irrigation water. The corresponding samples were collected and analyzed on a large regional scale. The total input fluxes show obvious spatial variability among different regions. The inventory of heavy metal inputs to agricultural land demonstrates that agricultural soil is potentially at risk of heavy metal accumulation from irrigation water. The potential at risk of heavy metal accumulation from atmospheric deposition and fertilizer is relatively low compared to irrigation. The results indicate that Hg is the element of prior concern for agricultural soil, followed by Cd and As, and other heavy metal elements represent little threat to the environment in the study area. This work provides baseline information to develop policies to control and reduce toxic elements accumulated in agricultural soil.     

Performance Characteristics of Instrumental Methods for Monitoring Sulfur Dioxide

The performance characteristics of commercially available continuous sulfur dioxide monitors were determined. Conductimetric, colorimetric, and coulometric analyzers were investigated. The study was conducted to develop information on such instrument characteristics as stability, sensitivity, response time, collection efficiency, and response to interfering substances. The methodology and apparatus used to determine each operational parameter are described. The instrument performance data developed in this study should be useful to those involved in selection of instrumental methods for monitoring atmospheric sulfur dioxide.     

不同功能区空气负离子的监测分析

监测了西宁地区不同功能区空气负离子状况，以公园游览区空气负离子浓度最高，平均３５８个／ｃｍ＾３；工业区最低，平均浓度２５９个／ｃｍ＾３。各功能区空气负离子浓度明显不同，Ｐ〈０．０１。用空气负离子浓度、空气离子单级系数和安培空气质量评价指数评价各功能区空气质量，从好到差依次为：公园游览区、生活居住区、商业交通繁忙区、工业区。３种评价指标结果相同，符合一般规律。     

方解石粉钝化太湖水中磷的能力及影响因素

利用轻质、重质和纳米方解石粉进行了去除太湖水中磷的实验研究,单位重量方解石粉除磷量与溶液中磷浓度正相关,轻质和重质方解石粉除磷规律符合Langmuir吸附等温式,极限除磷量分别为0.387 mg/g和0.351 mg/g,纳米方解石粉除磷规律符合Freundlich吸附等温式.方解石粉BET比表面积是影响方解石粉除磷能...     

Polychlorinated biphenyls and chlorinated pesticides in mussels from the Egyptian Red Sea coast

The residues of 17 organochlorine pollutants were analyzed in bivalve Brachiodontes sp. collected from 11 different locations in April 2000 along the Egyptian Red Sea coast. The pollutants studied were 10 individual polychlorinated biphenyl (PCB) congeners, alpha,alpha,alpha-hexachlorocyclohexane (HCHs), cyclodienes (heptachlor, heptachlorepoxide, aldrin, dieldrin) and dichlorodiphenyltrichloroethanes (DDTs) (p,p'-DDE, p,p'-DDD and p,p'-DDT). The concentration of total DDTs ranged between 125 and 772 ng/g of wet weight whereas the concentration of the PCBs, HCHs and cyclodienes ranged from 6.7 to 66.4 ng/g; 16.2 to 183.4 ng/g and 8.8 to 221.6 ng/g of wet weight, respectively. The levels are low to moderate in relation to the published data from other coastal areas. The present results indicate low to moderate PCBs and pesticides contamination in the investigated mussels except DDTs.     

Effectiveness and mechanisms of hydrogen sulfide adsorption by camphor-derived biochar

The characteristics and mechanisms of hydrogen sulfide (H2S) adsorption on a biochar through pyrolysis at various temperatures (100 to 500 degrees C) were investigated. The biochar used in the current study was derived from the camphor tree (Cinnamomum camphora). The samples were ground and sieved to produceparticle sizes of 0.4 mm to 1.25 mm, 0.3 mm to 0.4 mm, and <0.3 mm. The H2S breakthrough capacity was measured using a laboratory-designed test. The surface properties of the biochar were characterized using pH and Fourier-transform infrared spectroscopy (FTIR) analysis. The results obtained demonstrate that all camphor-derived biochars were effective in H2S sorption. Certain threshold ranges ofthepyrolysis temperature and surfacepH were observed, which, when exceeded, have dramatic effects on the H2S adsorption capacity. The sorption capacity ranged from 1.2 mg/g to 121.4 mg/g. The biochar with 0.3 mm to 0.4 mm particle size possesses a maximum sorption capacity at 400 degrees C. The pH and FTIR analysis results showed that carboxylic and hydroxide radical groups were responsible for H2S sorption. These observations will be helpful in designing biochar as engineered sorbents for the removal of H2S.     

pH值对霞湾港沉积物重金属Zn、Cu释放的影响

以霞湾港(铜霞路段)的底泥沉积物为研究对象,采用重金属连续浸提法对重金属Zn、Cu在沉积物中的5种形态进行浸提,分析了其分布特征和在不同pH值与时间的条件下重金属的释放规律。研究结果表明,重金属Zn主要以铁锰氧化物结合态和碳酸盐结合态的形态存在,Cu主要以有机结合态和残渣态的形态存在,可交换离子态的重金属含量都很低。重金属Zn、Cu从沉积物中的释放,主要是在酸性条件下发生,在酸性区内释放量随pH的升高而迅速降低。释放能力和释放速率均为ZnCu,它们释放的过程基本相似,释放速率都比较小,向环境中的释放是个长期过程。     

Rates of accumulation of dieldrin by a freshwater filter feeder: Sphaerium corneum

The rate of dieldrin accumulation by Sphaerium corneum was determined in the field and under controlled conditions in the laboratory. The methods gave comparable results and it was established that Sphaerium attained an equilibrium concentration of dieldrin in its tissues in a short time period and exhibited a bioaccumulation factor of 1000. The rate of dieldrin accumulation by direct uptake from dieldrin in solution was compared to the rate obtained for indirect uptake from dieldrin adsorbed onto particulate material. The primary route of dieldrin uptake into Sphaerium was shown to be by direct partitioning of residues into lipoidal tissues from water. The effect of temperature on the rate of accumulation was also studied. The rate of accumulation increased with temperature in the range 5 degrees C to 20 degrees C. The frequency of gill cilia beat in relation to accumulation rate was studied in this temperature range and a correlation is shown.     

Root growth responses of Anagallis arvensis L., primulaceae to air pollution

The root growth response to air pollution in populations of Anagallis arvensis growing about 0.5, 2, 6, 12 and 20 km leeward from a power plant complex varied with the level of pollution, age of the stand and meteorological conditions. The roots were more affected by the pollutants at a young stage and the loss in net primary productivity was proportional to the pollution level. The populations up to 2 km from the source of pollution completed their life cycle quickly. The coal consumption rate at the power plant, relative humidity, wind direction and other environmental factors were found to influence the degree of growth response to air pollution.     

牛粪厌氧发酵的载体筛选试验研究

为了提高厌氧发酵装置的效率,人们研究了各种各样的方法和措施,其中应用填料或载体使生物菌能够延长驻留期是其中的方法之一,开展载体筛选及其结构设计在厌氧发酵装置中的试验,有助于对此问题的深入研究以及将其成果应用于生产实践。通过静态载体筛选试验选择了玻璃纤维作为载体、PVC塑料管作为载体骨架制成的装置在动态序批式厌氧发酵装置中进行了试验。结果表明：此载体骨架结构对于牛粪动态厌氧发酵具有明显的提高产气效率、改变产气质量和促进有机物转化为挥发性脂肪酸的作用。