南京市可吸入颗粒物（PM10）来源及防治对策

通过分析南京市可吸入颗粒物（PM10）来源分布特征,以及源贡献值和分担率的时空分布特征,提出南京市大气颗粒物污染防治对策;加强防治扬尘污染,巩固煤烟尘的治理成果,机动车尾气尘污染防治,提高环境监测能力和加强科学研究等措施。     

Mercury accumulation and dynamics in montane forests along an elevation gradient in Southwest China

Understanding atmospheric mercury (Hg) accumulation in remote montane forests is critical to assess the Hg ecological risk to wildlife and human health. To quantify impacts of vegetation, climatic and topographic factors on Hg accumulation in montane forests, we assessed the Hg distribution and stoichiometric relations among Hg, carbon (C), and nitrogen (N) in four forest types along the elevation of Mt. Gongga. Our results show that Hg concentration in plant tissues follows the descending order of litter > leaf, bark > root > branch > bole wood, indicating the importance of atmospheric Hg uptake by foliage for Hg accumulation in plants. The foliar Hg/C (from 237.0 ± 171.4 to 56.8 ± 27.7 µg/kg) and Hg/N (from 7.5 ± 3.9 to 2.5 ± 1.2 mg/kg) both decrease along the elevation. These elevation gradients are caused by the heterogeneity of vegetation uptake of atmospheric Hg and the variation of atmospheric Hg° concentrations at different altitudes. Organic soil Hg accumulation is controlled by forest types, topographic and climatic factors, with the highest concentration in the mixed forest (244.9 ± 55.7 µg/kg) and the lowest value in the alpine forest (151.9 ± 44.5 µg/kg). Further analysis suggests that soil Hg is positively correlated to C (r² = 0.66) and N (r² = 0.57), and Hg/C and Hg/N both increase with the soil depth. These stoichiometric relations highlight the combined effects from environmental and climatic factors which mediating legacy Hg accumulation and selective Hg absorption during processes of organic soil mineralization.     

Improved atmospheric mercury simulation using updated gas-particle partition and organic aerosol concentrations

The gaseous or particulate forms of divalent mercury (Hg^II) significantly impact the spatial distribution of atmospheric mercury concentration and deposition flux (FLX). In the new nested-grid GEOS-Chem model, we try to modify the Hg^II gas-particle partitioning relationship with synchronous and hourly observations at four sites in China. Observations of gaseous oxidized Hg (GOM), particulate-bound Hg (PBM), and PM_2.5 were used to derive an empirical gas-particle partitioning coefficient as a function of temperature (T) and organic aerosol (OA) concentrations under different relative humidity (RH). Results showed that with increasing RH, the dominant process of Hg^II gas-particle partitioning changed from physical adsorption to chemical desorption. And the dominant factor of Hg^II gas-particle partitioning changed from T to OA concentrations. We thus improved the simulated OA concentration field by introducing intermediate-volatility and semi-volatile organic compounds (I/SVOCs) emission inventory into the model framework and refining the volatile distributions of I/SVOCs according to new filed tests in the recent literatures. Finally, normalized mean biases (NMBs) of monthly gaseous element mercury (GEM), GOM, PBM, WFLX were reduced from −33%–29%, 95%–300%, 64%–261%, 117%–122% to −13%–0%, −20%–80%, −31%–50%, −17%–23%. The improved model explains 69%–98% of the observed atmospheric Hg decrease during 2013–2020 and can serve as a useful tool to evaluate the effectiveness of the Minamata Convention on Mercury.     

浙江近岸海域海水和沉积物中铬形态分布特征研究

本研究在浙江近岸4个海域开展同步采样和观测,分析海水和沉积物中铬（Cr）形态分布特征。结果表明,表层海水总Cr浓度范围为0.405～0.653μg/L,Cr(Ⅵ)浓度范围为0.009～0.087μg/L;底层海水总Cr浓度范围为0.426～0.638μg/L,Cr(Ⅵ)范围为0.005～0.099μg/L,海水中Cr形态含量分布与深度无相关性。沉积物中Cr含量范围为50～82 mg/kg,以残渣态为主;有效态Cr的含量大小依次为有机结合态Cr>铁锰氧化物结合态Cr>离子交换态Cr>碳酸盐结合态Cr;沉积物中水溶态Cr(Ⅵ)含量范围为2.99～11.71μg/kg,小于0.02 mg/kg。上述结果表明,浙江近岸海域环境存在一定程度的Cr污染,但水溶态Cr(Ⅵ)含量低,潜在风险较小。     

Effect of filter-feeding fish silver carp on phytoplankton species and size distribution in surface water： A field study in water works

Silver carp were introduced into the pre-sedimentation pond to control excessive phytoplankton in raw water.The effectiveness of the filter-feeding silver carp on phytoplankton control and the effect of silver carp on phytoplankton community were investigated.The results showed that Microcystis could be effectively removed by silver carp stocked in the pre-sedimentation pond,and simultaneously,the concentration of single-cell phytoplankton increased obviously.The difference in phytoplankton species and singlecell phytoplankton size between in the water and in the gut of silver carp indicated that phytoplankton smaller than 5 μm,such as Chamydomonas and Platymonas,were almost not be filtered by silver carp,phytoplankton with the size between 5 and 20 μm could be partly filtered,and large size phytoplankton,mainly colony-forming Microcystis could be filtered almost completely.These filterfeeding characteristics directly caused the phytoplankton size distribution biased toward miniaturization.Therefore,this biological treatment using silver carp could be applied only to deal with groups of Microcystis-dominated eutrophic water,and was not appropriate in water bodies where single-cell micro phytoplankton were dominant.Especially when silver carp are used in water treatment,a cautious attitude should be taken based on the evaluation of phytoplankton biomass and species structure features in raw water.     

高压水射流超细粉碎云母的实验研究

利用前混合磨料射流的工作原理，进行了高压水射流超细粉碎云母的实验研究。实验结果表明：喷嘴对云母有粉碎作用，喷嘴直径可以小于云母给料粒度；压力是影响高压水射流超细粉碎效果的最重要参数，在压力为１０—５０ＭＰａ范围内，细粒度产率随压力增加呈直线上升；给料粒度越小，粉碎产品中细粒度的产率越高；水射流超细粉碎在淹没状态下比在非淹没状态下粉碎效果好；高压水射流超细粉碎云母粉，不但能够满足珠光云母粉的细度要求，而且能够保护云母的片状结构和晶面光泽度；高压水射流超细粉碎技术是一种较实用的超细粉碎云母技术。     

高压水射流超细粉碎云母的粒度特性方程式

为了弄清高压水射流超细粉碎云母的规律，本文通过假设颗粒中的校裂纹、表面裂纹和体裂纹的扩展概率相互独立，以及颗粒中发生多少个裂纹扩展的概率服从普哇松分布，推导出粒度特性方程；并认为裂纹扩展概率与水压成正比，与给料调和平均粒率成反比；然后用粒度特性方程拟合和分析了高压水射流超细粉碎云母的实验测试数据，发现高压水射流超细粉碎云母主要是云母粉中的棱裂纹扩展所致，且粒度分布由水压和给料调和平均粒度决定。     

扬水曝气器的水质改善功能及提水、充氧性能研究

扬水曝气器是水源水质改善设备,应用于湖泊水库水源地,抑制藻类生长,控制底泥污染物释放,取得了良好的效果.建立了扬水曝气器上升流速数学模型,用于模拟计算扬水曝气器的提水能力.建立了扬水曝气器曝气室的充氧能力数学模型.在实验室实测了扬水曝气器上升流速及其对水体的充氧过程,实测值与模拟计算值吻合较好,验证了提水、充氧能力数学模型.     

Remediation mechanisms of mercapto-grafted palygorskite for cadmium pollutant in paddy soil

The immobilization agent was the key factor that determined the success of remediation of heavy metal polluted soil. In this study, mercapto-grafted palygorskite (MP) as a novel and efficient immobilization agent was utilized for the remediation of Cd-polluted paddy soil in pot trials, and the remediation mechanisms were investigated in the aspect of soil chemistry and plant physiology with different rice cultivars as model plants. Mercapto-grafted palygorskite at applied doses of 0.1–0.3% could reduce Cd contents of brown rice and straws of different cultivars significantly. Both reduced DTPA-extractable Cd contents in rhizosphere and non-rhizosphere soil and decreasing Cd contents in iron plaques on rice root surfaces confirmed that MP was an efficient immobilization agent for Cd pollutant in paddy soil. In the aspect of soil chemistry, the pH values of rhizosphere and non-rhizosphere soils had no statistical changes in the MP treatment groups, but their zeta potentials decreased obviously, indicating that MP could enhance the fixation or sorption of Cd on soil compositions. In the aspect of antioxidant system, MP could increase POD activity of rice roots significantly to alleviate the stress of Cd to roots, and resulted in the decrease of T-AOC, SOD, and CAT activities of rice roots of the selected cultivars. MP had no inhabitation or enhancement effects on TSH of rice roots but enhance the contents of MTs and NPT to binding Cd to complete detoxification process. MP as a novel and efficient immobilization agent could complete the remediation effects through soil chemistry and plant physiological mechanisms.

     

A fuzzy analytic hierarchy process (FAHP) approach to eco-environmental vulnerability assessment for the danjiangkou reservoir area,China

The Danjiangkou reservoir lies in the upper Hanjiang basin and is the source of water for the Middle Route Project (MRP) under the South-to-North Water Transfer Scheme (SNWT) in China. The eco-environment of water resource areas plays an important role in water conservation and purification and would have significant implications for the economic prosperity in Hanjiang basin as well as for the SNWT. Focusing on the Danjiangkou Reservoir Area (DRA), this study established an environmental information system database. Based on the database, an eco-environmental vulnerability assessment method using integrated fuzzy AHP (FAHP) and GIS was developed for the DRA. According to eco-environmental conditions and anthropic effects, vulnerability was classified into five levels: potential, light, medium, heavy and very heavy. The eco-environmental vulnerability distribution and major problems of the eco-environment were analysed and discussed. The results indicated that eco-environmental vulnerability in the DRA was moderate overall. Regions with lower eco-environmental vulnerability were located in Qinling Mountain area in the northwest, Daba Mountain area in the south and the area immediately surrounding Danjiangkou Reservoir in the east. Two regions with very high eco-environmental vulnerability were located in the north of Danjiangkou Reservoir in Henan province and in the western part of Shanxi province. On the basis of analysis of distribution of the different factors of eco-environmental vulnerability, different environmental protection measures were proposed for different areas. This study demonstrated that the proposed method was an effective approach for the assessment of environmental vulnerability. The results gained closely reflected the reality of the eco-environmental vulnerability of the DRA.