南京市霾天气与主要气象条件的相关分析

利用天气学原理,分析研究2012~2014年南京市霾天气的主要地面天气形势、气象要素以及PM2.5与PM10浓度的相互关系.结果表明,2012~2014年南京市霾天气以轻度和轻微霾为主,且冬季最多,夏季最少;相对湿度在50%~80%之间有利于霾的发生,尤其是70%≤RH<80%时;有87.6%的霾发生在风速≤4m/s的情况下,并且主要来自东北偏东到东南风向区域.最利于南京霾天气形成的主要天气形势是均压场、高压控制和高压后部,而低压槽、副高控制和台风影响时霾发生较少.PM2.5在PM10中所占比例与霾强度呈正比.通过对南京市气象条件与霾的关系,及后向轨迹HYSPLIT4模式的聚类分析显示,结合南京市霾天气时的风向统计,影响南京霾发生的污染源主要有本地源、南京市东南地区的近距离污染源和华北地区的远距离污染源.     

青岛大气气溶胶中微量元素溶解度及影响因素

利用2012年12月在青岛采集的31个总悬浮颗粒物（TSP）样品,分析其中11种微量元素的总浓度和溶解态浓度,讨论了沙尘负载、气溶胶来源、酸过程及天气条件对微量元素溶解度的影响.结果表明,Fe和Al的溶解度<5%,Pb、Ba、Bi的为10%左右,Cu、V、Cd、Mn的为20%~30%,Zn和As的约为40%.随着沙尘负载量的增加,气溶胶中微量元素溶解度呈规律性递减.气团后向轨迹聚类分析和正矩阵因子分析（PMF）结果显示,受人为源影响的气溶胶中微量元素溶解度明显高于受沙尘源影响的,受二次生成源和海洋源影响的的气溶胶中微量元素溶解度明显高于受土壤源影响的.大气酸过程是造成这些差异的主要原因.相关性分析表明,SO₄^2-、NO₃^-和有机酸等酸组分均对微量元素溶解度有一定影响.霾天时气溶胶中微量元素溶解度明显低于雾天的,其原因为酸组分在较高的相对湿度下更能促进微量元素溶解度的提高.     

Trace elements in fish and oysters from Sepetiba Bay (Rio de Janeiro – Brazil) determined by total reflection X-ray fluorescence using synchrotron radiation

Trace elements were determined in fish and oysters from Sepetiba Bay, Brazil, by total reflection Xray fluorescence using synchrotron radiation (SRTXRF). Cr, Mn, Fe, Ni, Cu, Zn and Se were determined in fish muscles and organs and in oyster soft tissue. SRTXRF was shown to be a good tool for the analysis of trace elements from biological tissue samples. Overall, the levels of the analysed metals were higher in oysters than in the fish samples. Metals were not uniformly distributed throughout the body of the analysed fish. The detected concentrations of Cr, Zn and Se were very high in some samples, surpassing the maximum limits established by Brazilian legislation.     

Essential and toxic elements in meat of wild and bred animals

Essential and toxic elements were determined by Energy Dispersive Polarized X-Rays Fluorescence Spectrometry (EDPXRF) in the meat of 145 wild and bred animals to provide the baseline data regarding meat of wild and bred animals consumed in central Italy. As far as K, Fe, Ni, Zn, and Cu are concerned, no significant differences resulted between young and adults and between males and females for farmed and wild animals. No marked differences were found between hunted and non-hunted animals groups. In all samples analyzed, Mn, Cr, and Mo were below the detection limit. As far as the non-essential or toxic elements are concerned, As, Cd, V, and Hg concentrations in muscle from wild and bred animals were low and always below the detection limits. Among the wild animals killed with lead (Pb) bullets, elevated Pb concentrations in tissues were detected. This finding may result in elevated Pb levels in meat ingested by humans.     

Physicochemical characteristics and distribution of some metals in the ecosystem of Lake Nasser,Egypt

To know the interrelationship between some metals in different ecosystem components (water, sediment, aquatic plant and fish), many samples from these components were collected from four bights at the Nasser Lake, Egypt, and analyzed for Fe, Mn, Zn, Ca, Mg, Pb, Cd, Ni, Co, Cu and Cr using atomic absorption spectrophotometer. Different distribution factors (bioaccumulation factor – BF, discrimination factor – DF and enrichment factor – EF) were applied on the results of analysis. Data showed that the relatively high concentration of measured metals in water samples are derived from fish farms, and discharge of tourism and trade ships. Applying single leaching sequential technique on sediment samples, using different extracting solutions, revealed a strong ability of trace metals to adsorb on or co-precipitate with amorphous Fe/Mn oxides. High concentrations of Fe, Mn, Co and Ni were measured in the intestine while high Cd and Cr concentrations were recorded in the stomach in both Tilapia (nilotica and galilea). Tilapia galilea accumulated high Pb, Cu and Zn concentrations in their stomach, while in nilotica high concentrations of Pb, Cu and Zn were measured in the intestine, liver and muscles, respectively. Myriophyllum spicatum (an aquatic plant) in the lake recorded high concentrations of Fe, Mn and Zn. Bioaccumulation factors of studied elements in the different bights components indicate that the elevated concentration of measured elements in the aquatic plant and Tilapia (nilotica and galilea) are derived from water, reflecting the increase of human activities in Nasser Lake in recent years. However, the present study concluded that all the elements studied were still below the natural back-ground levels, except Zn and Cu.     

Source and Distribution of Heavy Metals in Food†

Diet is the major route of exposure to contaminants, therefore food monitoring programs are essential to estimate the degree of human risk. We present a study undertaken in Austria dealing with the total uptake of mercury, cadmium, arsenic and lead. The dates were calculated from diet as well as from commercial food. Higher contaminated foodstuffs are registered and a comparison was made between body burden of babies and adults on the basis of bodyweight. It was pointed out, that cooked or washed food ready to eat has a lower burden of lead and cadmium than non prepared food due to household processing, which may decontaminate food to some extent’ Arsenic content was not reduced, because it is bound chemically and not primarily deposited on the surface of food such as in the case of lead. It was mentioned that the type of compound plays an important role in the assessment of action of those elements on humans.

Their biological activity is not necessarily related to their concentration in food. As in the case of selenium and chromium one has to take into consideration that there is a narrow range between benefit and harm, toxicity, and minor supply.

Therefore we conclude, that due to interactions of elements, their different biological activity and due to the difference of compounds present in food, we have to relativate the terms toxicity and essentiality. Then we can get a more profound insight into the problems of trace elements in food.     

Neutron activation and atomic absorption analysis of Ulva Lactuca and Gracilaria Verrucosa from Thermaikos Gulf,Greece

NAA and AAS have been applied to determine the content of As, Br, Ca, Cd, Co, Cr, Cu, Fe, K, La, Mn, Na, Ni, Pb, Sb, Sc, Sm and Zn in Ulva lactuca and Gracilaria verrucosa from Thermaikos Gulf, Greece. The analytical data has been subjected to cluster and stepwise discriminant analysis. Thus the influence of some industrial sources on the pollution of water in the Gulf is detected and correlation between Zn‐Co‐Cr‐La; Br‐K; Cu‐Ni; Cd‐Sb‐Mn in the investigated algae is established.     

Concentrations of various elements and inorganic ions in rice straw and ash

Various elements and inorganic ions in rice straw and ash samples were analyzed by using inductively coupled plasma atomic emission spectrometry (ICP‐AES) and ion chromatography (IC). Five major elements: Mg, Mn, Al, Ca, and Fe and eight minor and trace elements: Cr, Cu, Ti, Zn, La, Sr, Ba, and Hg were detected in these samples, at more than ppm‐level. In ash samples the trace elements such as Y, As, V, Se, and Sc were also identified. The concentrations of SO₄, PO₄, Cl, Na, and K ions in these samples were higher than those of other ions measured. These elements and inorganic ion concentrations were approximately one order of magnitude higher in the ash than in the straw samples. Gas chromatography/mass spectrometry (GC/MS) and library search showed the presence of fatty‐, carboxylic‐ and nicotinic acids, and their derivatives in small quantities in the straw samples.     

Pollution characteristics of lead,zinc, arsenic,and cadmium in short-term storm water roof runoff in a suburban area

Pollution of hazardous elements in roof runoff has been a potential danger to aquatic ecosystem as documented in previous studies. In this study, concentrations of lead (Pb), zinc (Zn), arsenic (As), and cadmium (Cd) in roof runoff were measured for short-term rainfall events. The concentrations of the selected elements varied to a high degree during the rainfall period, and the well-known first-flush phenomenon was not observed due to the short-term rainfall patterns. Based on event mean concentrations (EMCs) and fluxes, the elemental pollution may be ranked as Zn >> Pb > As > Cd. The average levels of Pb and Zn exceeded the fourth class value and fifth class value of the environmental quality standards for surface water in China. The relative high pollution could be caused by atmospheric deposition and the erosion of crust steel appurtenance installed above the rooftop. Furthermore, elements in particulate form dominated the roof runoff pollution, and the ratios of elements in particulate form to total amounts were 0.6 (As), 0.9 (Pb), 0.7 (Cd), and 0.5 (Zn). This study cleared the pollution characteristics of hazardous elements in short-term storm water roof runoff; it was useful for the selection of best management practices.