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711.
Chen Yang Li Peijun Carlo Lupi Sun Yangzhao Xu Diandou Feng Qian Fu Shasha 《Waste management (New York, N.Y.)》2009,29(6):1996-2004
This paper discusses actions aimed at sustainable management of healthcare wastes (HCW) in China, taking into account the current national situation in this field, as well as the requirements deriving from the Stockholm Convention on Persistent Organic Pollutants and the WHO recommendations. By the end of 2005, there were 149 low-standard HCW disposal facilities in operation in China, distributed throughout different areas. According to the National Hazardous Waste and Healthcare Waste Disposal Facility Construction Plan, 331 modern, high-standard, centralized facilities will be built up in China in municipal level cities. Although incineration is still the main technical option for HCW disposal in China, it is expected that, especially for medium and small size facilities, non-incineration technologies will develop quickly and will soon become the main technical option. The basic management needs – both from the point of view of pollution control and final disposal – have been defined, and a system of technical and environmental standards has been formulated and implemented; however, there are still some shortages. This is particularly true when considering the best available techniques and best environmental practices developed under the Stockholm Convention, with which the present technological and managing situations are not completely compliant. In this framework, the lifecycle (from generation to final disposal of wastes) of HCW and holistic approaches (technology verification, facilities operation, environmental supervision, environmental monitoring, training system, financial mechanism, etc.) towards HCW management are the most important criteria for the sustainable and reliable management of HCW in China. 相似文献
712.
713.
Adsorption of lambda-cyhalothrin and cypermethrin on two typical Chinese soils as affected by copper
Jun Liu Xiaomeng Lü Jimin Xie Yafei Chu Cheng Sun Qian Wang 《Environmental science and pollution research international》2009,16(4):414-422
Background, aim, and scope Pesticides and heavy metals pollution in soil environment has become a serious problem in many countries including China.
Repeated applications of bordeaux mixture (a blend of copper sulfate and calcium hydroxide) and pyrethroid (Pys) insecticides
have led to elevated copper (Cu) and Pys concentrations in vineyard surface soils. However, few studies focused on the interaction
of Pys and heavy metals in the soil environment. Our previous studies had indicated the combined effect of cypermethrin (CPM)
and Cu on soil catalase activity. Also, we had suggested that the addition of Cu could catalyze photo-degradation of CPM and
lambda-cyhalothrin (λ-CHT) in aqueous solution and restrain their degradation in soil. To better understand the potential
influence of Cu on the fate of Pys in the soil environment, the aim of the present work was to examine the effect of Cu on
the adsorption of λ-CHT and CPM on two typical Chinese soils with different soil characteristics, which was one of the key
processes controlling the fate of Pys, and to provide more information about the potential ecological risk of chemicals on
the soil ecosystem. Fourier transform infrared and point charges analysis using the MOPAC program of the Gaussian system were
also used to reveal the probable adsorption mechanism of λ-CHT and CPM on soils.
Materials and methods Two vineyard soils with different properties were chosen as experimental samples. They were sampled from 0 to 10 cm, dried,
and sieved to 2 mm. Each soil was spiked with copper sulfate solution to obtain the following total soil Cu concentrations:
100, 200, 400, 800, and 1,600 mg·kg−1. The treated soils were incubated for 2 weeks and then dried at 20°C. For each soil sample and at each soil Cu concentration,
the adsorption of λ-CHT and CPM was measured using a batch equilibrium method. The concentration of λ-CHT was determined by
HPLC, and the amount of λ-CHT and CPM adsorbed by the soil sample at equilibrium was determined by the difference between
the initial and equilibrium concentrations in solution corrected by the blank adsorption measurement.
Results Without the addition of Cu, the adsorption of λ-CHT and CPM on Black soil is greater than that on Red soil, while the adsorption
of λ-CHT on both soils is significantly stronger than that of CPM. As the soil Cu concentration increased from 19 (or 18;
background) to 1,600 mg·kg−1, the adsorption coefficient (K
d) of λ-CHT decreased from 12.2 to 5.9 L·kg−1 for Red soil, and from 26.1 to 16.8 L·kg−1 for Black soil, whereas the CPM adsorption coefficient in both soils decreased nearly by 100% (K
d decreased from 9.4 to 0.2 L·kg−1 for Red soil and from 16.2 to 0.5 L·kg−1 for Black soil).
Discussion Pys adsorption is a surface phenomenon which depends on the surface area and the organic matter content. Thus, the Black soil,
having higher organic matter and greater surface area than that of the Red soil, show greater adsorption affinity to λ-CHT
and CPM. In our study, the different adsorption affinity of the two Pys was obtained, which was probably attributed to differences
with respect to their physical–chemical properties. Further comparison upon the two Pys was conducted. The point charges of
halogen atoms in the λ-CHT and CPM were calculated, the differences of which probably lead to the fact that λ-CHT has a stronger
binding capacity to soils than CPM. Also, FTIR spectra show that competitive adsorption occurs between CPM and Cu for the
same adsorption sites, which is responsible for the obtained suppression of CPM adsorption affected by Cu.
Conclusions Lambda-cyhalothrin shows a significantly stronger adsorption than cypermethrin on both soils. This phenomenon may be due to
several reasons: (1) λ-CHT has lower solubility and a higher octanol–water partition coefficient value than CPM; (2) λ-CHT
consists of specific isomers, whereas CPM is mixtures of eight different isomers; (3) the chlorine and fluorine atoms in the
λ-CHT have a negative point charge, whereas the chlorine atoms in the CPM have a positive point charge. As the soil Cu concentrations
increased from 19 (or 18) mg·kg−1 to 1,600 mg·kg−1, the adsorption coefficient of λ-CHT and CPM decreased on both soils. This is mainly due to a competition between Cu and
Pys for occupying the adsorption sites on soils. The information from this study have important implications for vineyard
and orchard soils, which often contain elevated levels of Cu and Pys. These results are also useful in assessing the environmental
fate and health effect of λ-CHT and CPM.
Recommendations and perspectives It is important for environmental scientists and engineers to get a better understanding of soil–metal–organic contaminant
interactions. However, pesticide adsorption involves complex processes, and shortcomings in understanding them still restrict
the ability to predict the fate and behavior of pesticide. Therefore, considerable research should be carried out to understand
the mechanism of interaction between Pys and heavy metal on soils clearly. 相似文献
714.
不同污泥浓度对生物沥滤过程的影响 总被引:2,自引:1,他引:1
以硫酸亚铁盐作为底物,氧化亚铁硫杆菌(Thiobacillus ferrooxidans)为主要沥滤微生物,在底物投配比为10 g/L,温度为25℃,曝气量为1 L/min的条件下,对5种不同浓度的桂林城市污泥中重金属进行生物沥滤试验。结果表明,生物沥滤的污泥浓度宜控制在25.6 g/L,沥滤3 d后,污泥中超标元素Cu、Zn和Cd的去除率分别达到58.17%、75.90%和93.64%,沥滤处理后污泥中残余重金属含量符合污泥农用的国家标准。 相似文献
715.
716.
717.
镉胁迫对向日葵幼苗生长和生理特性的影响 总被引:7,自引:0,他引:7
采用溶液培养方法,研究了不同浓度镉(0、0.05、0.1、0.5和1 mg/L)处理7 d对向日葵幼苗生长和生理特性的影响。结果表明:随着镉处理浓度的增加,向日葵幼苗对镉的吸收显著增加。1 mg/L镉浓度处理时,叶、茎和根中镉浓度分别为0.05 mg/L镉处理时的16.3、19.2和581倍;根中积累的镉含量明显高于叶和茎, 各浓度根部积累的镉分别为叶和茎的37.8~63倍和29.4~41倍。镉胁迫显著抑制向日葵幼苗生长和叶绿素合成,当镉浓度达1 mg/L时,整株植物生物量和总叶绿素含量分别为对照的55.9%和52.6%。镉胁迫下向日葵幼苗游离脯氨酸和丙二醛(MDA)含量显著增加,1 mg/L镉浓度时,根中含量分别为对照的4和5.8倍。向日葵幼苗可溶性蛋白含量和过氧化物酶(POD)活性变化与镉胁迫浓度呈明显的倒U字型关系,可溶性蛋白含量在0.05 mg/L镉浓度时达到最大值,叶、茎、根中的POD活性分别在0.1、0.1和0.05 mg/L镉浓度时达到最大值。 相似文献
718.
Based on the concept of ecosystem carrying capacity, the indicator system of quantitative assessment was set up, which consisted of support indicator system and pressure indicator system. And the factor analysis method was used to screen the indicator system. Different from the traditional indicator weight determination based on the absolute values of the coefficients of regression equation, the squares of factor loadings in the rotated component matrix were attempted to determine the weights of 40 assessment indicators. The result shows that ecological support system and pressure system in Binhai New Area are relatively balanced among six years, and the developing level of urban ecosystem is basically healthy on the whole. However, due to continuously increasing pressure of the resources consumption caused by the rapid growth of the second industry, which is the Leading Industry of Binhai New Area, the ecosystem carrying capacity reached the minimum in 2005. 相似文献
719.
防弹头盔研制技术及发展前景 总被引:1,自引:0,他引:1
孙幸福 《中国个体防护装备》2009,(1)
战伤统计表明,装备防弹头盔可有效降低士兵的伤亡率.高性能纤维及其在防弹头盔上的应用技术的发展,使其在轻量化的同时获得了更高的防护性能.本文论述了复合材料防弹头盔盔型设计和成型加工技术的要素,探讨了当前军用头盔功能高度集成化趋势对头盔设计和加工技术的影响. 相似文献
720.
10%丁醚脲微乳剂在甘蓝和土壤中的残留及消解动态研究 总被引:1,自引:0,他引:1
建立了丁醚脲在甘蓝及土壤中残留量的高效液相色谱检测方法,并采用田间试验方法对丁醚脲在甘蓝及土壤中的残留消解动态进行研究,开展了最终残留试验.结果表明,在0.05~5.0 mg/kg添加水平范围内,丁醚脲在甘蓝和土壤中的平均添加回收率为82.5%~100.9%,相对标准偏差为4.5%~7.5%.残留消解动态研究表明,丁醚脲在甘蓝和土壤中的降解符合方程式Ct=C0e-kt;10%丁醚脲微乳剂在甘蓝和土壤中的半衰期分别为2.87~2.99 d和3.37~3.57 d.最终残留试验研究表明,在施用有效成分约为0.02~0.04 g/m2,施药1~2次,每次施药间隔期为7 d的情况下,北京市试验地内,10%丁醚脲微乳剂在甘蓝中的残留量为ND~0.18 mg/kg,土壤中的残留量为0.09~0.37 mg/kg;湖南冷水江市试验地内,10%丁醚脲微乳剂在甘蓝中的残留量为ND~0.24 mg/kg;土壤中的残留量为0.11~0.46mg/kg.对照日本的最大残留限量标准,产品符合我国及日本规定的质量安全要求. 相似文献