Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

煤及其燃烧产物中砷的分布特征

首先研究了我国各主要聚煤区煤中砷的分布,煤的砷含量均值高于世界但低于美国,低于或接近我国土壤砷含量,但与地壳克拉克值比较,砷在煤中被明显富集。从各聚煤区情况看,砷的含量和富集因子均有中新生代煤最大,华南二叠纪煤为次,而华北石炭——二叠纪煤最小的特点。煤各级燃烧产物中砷分布研究表明,底灰中亏损,但富集于飞灰特别是细粒飞灰的表面,质量平衡率的计算显示砷大多能截留于飞灰中,呈蒸气状态逸散入大气的有限。      

双硫腙法研究废电池中汞的分布及浸出

用双硫腙法测定了几种废电池中汞的含量和分布及在不同水环境条件下,汞的浸出率,试图为废电池中各组分去汞后的回收提供理论依据。结果表明,双硫腙测定废电池中汞的方法是可靠的;汞在废电池中主要分布在锌皮（锌粉）和碳包部分;pH对汞的浸出率有较大的影响,浸出率与pH呈负相关。     

镇江市金山湖沉积物磷元素分布特征研究

以镇江市金山湖为研究区域,于2019年1月（冬季）和2019年7月（夏季）采集了10个点位的表层沉积物样品,参照欧洲标准测试测量组织建立的沉积物磷形态分析方法（SMT）测定沉积物总磷（TP）、无机磷（IP）、有机磷（OP）、铁/铝-磷（Fe/Al-P）和钙-磷（Ca-P）质量分数,研究金山湖表层沉积物磷元素及其赋存形态的季节分布特征。结果表明,金山湖表层沉积物中TP质量分数在冬、夏季分别为727.39~1 073.70 mg/kg和700.90~1 002.17 mg/kg,处于中等污染水平;金山湖表层沉积物磷以IP为主,IP在TP中的占比在冬、夏季分别为68.58%~88.86%,73.09%~87.21%;除了Fe/Al-P以外,OP作为生物有效磷源,其冬、夏季质量分数分别为69.37~190.93 mg/kg和108.45~210.42 mg/kg;其平均值分别为129.01,160.15 mg/kg。金山湖冬、夏季沉积物各形态磷质量分数所占比例均表现为Ca-P>Fe/Al-P>OP,表明该研究区域沉积物以Ca-P占优势。金山湖表层沉积物pH值呈现弱碱性,通过Ca-P直接释放到上覆水中的磷较少,故金山湖沉积物磷元素的潜在风险较小。各形态磷的相关性分析结果发现,冬季沉积物TP与Fe/Al-P、IP呈极显著正相关（P<0.01）。夏季沉积物TP与IP、Fe/Al-P之间呈极显著正相关（P<0.01）,与Ca-P呈显著正相关（P<0.05）。此外,金山湖沉积物OP、Fe/Al-P以及Ca-P的来源不一致。pH值对沉积物IP会产生一定影响,而其余磷形态则受pH值的影响程度较小。     

南宁市土壤中正构烷烃的污染特征及来源解析

为研究南宁市土壤中正构烷烃的赋存情况以及来源,于2021年6月在南宁市内采集了48个土壤样品,采用气相色谱质谱法(GC-MS)对表层土壤中正构烷烃的质量分数进行了测定。结果表明,正构烷烃碳链长度范围为C12—C35,∑24正构烷烃的质量分数为3.93~131.02μg/g,其中C31质量分数最高,C22以上的高碳正构烷烃具有明显的奇偶优势,体现了典型的高等植物来源的特点。碳优势指数等参数分析结果表明,土壤中的正构烷烃主要来自陆地高等植物且总体上木本植物>草本植物,少部分可能存在石油污染。主成分分析(PCA)结果表明,C29—C35具有同源性,主要受植物叶蜡影响(41.36%),C24和C25主要来自水生植物(27.88%),C16和C18可能是细菌和石油化合物排放共同影响的结果(21.49%)。根据主成分分析中样品的贡献权重得出,可能存在石油化合物输入的土壤63.6%来自耕地,27.3%来自林地,9.1%来自园地,研究区土壤中正构烷烃的主要人为排放源可能受到农业机械排放以及靠近道路周边受交通排放的影响。     

南京某燃煤电厂汞的排放特点及分布特征

选择南京某燃煤电厂330 MW机组,对煤、炉渣、粉煤灰、烟尘、石灰石、石膏和烟气中的汞取样测量,探讨煤中汞在燃烧过程中的变化情况,并进一步分析汞的排放特点及分布特征。指出,煤经燃煤锅炉炉内高温燃烧后,炉渣中的汞对环境影响不明显;粉煤灰、烟尘中的汞存在富集现象,且随着粒径变细,富集程度加剧;燃煤锅炉燃烧后,随石膏排放的汞占比较大,应采取相应的防治措施。     

Monitoring of Coliforms and chlorine residual in water distribution network of Rawalpindi, Pakistan

The present study was undertaken to examine the drinking water quality of Rawal Treatment Plant, Rawalpindi and its distribution network by collecting samples from eight different locations. The aim was to determine potential relationship between the presence of microorganisms and chlorine residual in the distribution network. Quantification of chlorine residual, turbidity, standard plate count (SPC), fecal and total coliforms by Most Probable Number (MPN) was performed. Three different forms of chlorine were measured at each sampling station such as free chlorine, residual chlorine, chloramines and total chlorine residual. A critical evaluation of data presented indicated that pH generally ranged from 7.02–7.30; turbidity varied from 0.34–2.79 NTU; conductivity fluctuated from 359–374 μS/cm; and TDS values were found to be ranging between 180–187 mg/l. Station # 7 was found to be most contaminated. The value of total chlorine was found to be 0.86 to1.7 mg/l at Station # 3 and 6, respectively. Highest standard plate count was 62 CFU/ml at Station # 7. Total coliforms were less than 1.1 MPN/100 ml at almost most of the stations except at Station # 3 where it was found to be greater than 23.0 MPN /100 ml. Overall aim of this study is to create awareness about contamination of drinking water in the water distribution networks and to make recommendations to provincial agencies such as EPA, CDA and WASA that regular monitoring should be carried out to ensure that the chlorine residual is available at consumer end.     

Phosphorus fractions and adsorption characteristics of floodplain sediments in the lower reaches of the Hanjiang River, China

The phosphorus fractions and adsorption characteristics of seven floodplain sediment samples collected in the lower reaches of China’s Hanjiang River were studied. Most phosphorus fractions showed a marked downstream increase in response to point-source inputs from urban areas. Total phosphorus (TP) contents in the sediments ranged from 603.68 to 945.25 mg.kg⁻¹. Inorganic phosphorus (IP) was the major component of TP, and calcium-bound phosphorus (Ca–P) was the major fraction of IP. The distribution characteristics of the phosphorus contents were affected by sediment grain size and hydrodynamic conditions. The maximum phosphorus adsorption capacities (Q _max) and the half-saturation concentration (k) were obtained using an improved Langmuir model. Native adsorbed exchangeable phosphorus content (w _NAP) and the zero-equilibrium phosphorus concentration value (c _EPC0) were subsequently calculated. The effects of sediment grain size, temperature, and disturbance on the phosphorus adsorption isotherms were also studied. The results showed that phosphorus adsorption on floodplain sediments was primarily chemisorption; the particle concentration effect played a more important role at a disturbance intensity of 150 r.min⁻¹ (on a shaker table) than at 100 r.min⁻¹.     

New best estimates for radionuclide solid–liquid distribution coefficients in soils,Part 1: radiostrontium and radiocaesium

Best estimates for the solid-liquid distribution coefficients (K_d) of radiostrontium and radiocaesium for various soil types, were derived from geometric means (GM) calculated from grouping soils by texture and organic matter content, and also using soil cofactors governing soil–radionuclide interaction. The K_d (Sr) GM for Sand, Loam, Clay and Organic groups were similar, although the value for the Sand group was significantly lower. The Sr cofactor approach, based on the ratios of cation exchange capacity (CEC) to Ca and Mg concentrations in the soil solution, leads to K_d (Sr) GM with a lower variability, from which best estimates could be proposed. The K_d (Cs) GM for Sand and Organic groups differed, although similar values were obtained for Loam and Clay groups. Grouping the K_d (Cs) according to the Radiocaesium Interception Potential (RIP) and the RIP divided by the K concentration in the soil solution also allows to suggest K_d (Cs) best estimates with a lower variability.     

含油废水粗粒化处理过程中除油率和油珠粒径分散度的研究

除油率和油珠粒径分散度是检验石化含油废水处理效果的两个重要指标。通过测定废水粗粒化处理前后分光光度值和油珠粒径的分布，较为精确地计算出含油废水处理后出水的除油率和油珠粒径分散度。采用紫外分光光度法测定含油量，显徽镜计数法测定油珠粒径分布，方法简单可靠。