Determination of trace metals in rain water by differential-pulse stripping voltammetry

Differential-pulse stripping voltammetry is applied to measure zinc, cadmium, lead and copper by anodic stripping and selenium(IV) by cathodic stripping in rain water at pH 2; subsequently, at pH 9,1, manganese is measured by anodic stripping on the same portion, and cobalt and nickel are measured in the adsorptive mode after formation of their dimethylglyoximates. The instrumental parameters are optimized. The linear ranges, mutual interferences and detection limits are studied. Excellent accuracy is demonstrated; the standard deviation is around 15% at 2.5–50 μg l^?1 levels. The method is shown to be applicable for rain water.     

Phenolics content and antioxidant activity of tartary buckwheat from different locations

Two tartary buckwheat samples (Xingku No.2 and Diqing) grown at three locations were analyzed for free and bound phenolic content and antioxidant properties. Moreover, the relative contributions of variety and growing environment to phenolic content and antioxidant properties were determined, as well as correlations of these properties to growing conditions. The total phenolic contents varied from 5,150 to 9,660 μmol of gallic acid equivalents per 100 gram of dry weight (DW) of tartary buckwheat and the free phenolics accounted for 94% to 99%. Rutin content was in the range from 518.54 to 1,447.87 mg per 100 gram of DW of tartary buckwheat. p-Hydroxybenzoic, ferulic and protocatechuic acids were the prominent phenolic acids and other phenolics, including p-coumaric, gallic, caffeic, vanillic and syringic acids were also detected. Tartary buckwheat exhibited higher DPPH· and ABTS·+ scavenging activities and was more effective at preventing the bleaching of β-carotene in comparison with reference antioxidant and plant phenolics constituents. Additionally, growing conditions and the interaction between variety and environment may have more contribution than variety to individual phenolics and antioxidant properties of tartary buckwheat. Environmental parameters such as higher altitudes may also have an increasing effect on rutin and phenolic acids. This study suggests that tartary buckwheat has potential health benefits because of its high phenolic content and antioxidant properties. These components could also be enhanced by optimizing the growing conditions of a selected variety.     

Vertical distribution of rhenium in seawater samples collected at three locations off the coast of Aomori, Japan

Summary The behavior rhenium in surface seawater (0-30 m) was studied using the samples collected at three locations off the coast of Aomori Prefecture, Japan. The physico-chemical forms of Re in seawater from other locations were also studied to verify the Aomori findings. It was found that almost 100% of Re was in dissolved forms, mainly ReO₄^-, therefore, the Re concentration was constant from the surface to 30 m depth and ranged from 6.1-7.4 ng^. kg^-1. The Re concentration in the Sea of Japan side was slightly lower than those in the Pacific Ocean side. Possibly, low Re concentration was added by river waters from Japan and/or the Asian continent to the Sea of Japan side.     

Particle size distribution of mineral phases and metals in dusts collected at different workplaces

Summary Airborne dusts were collected by a two-stage sampler on an electrically activated filter at different working places. Inhalable size (particles are less than 5 m) and course fractions were separated by a cyclone. The particle size distribution of three minerals (quartz, calcite, albite) and four metals (Pb, Cd, Cr, Co) was determined. Infrared spectroscopic and AAS methods were applied. The quartz concentrated in the course fractions while the calcite in the inhalable ones. No direct relation to the size fractions was found for albite. The toxic metals were extremely enriched in the fine fractions, in some cases 5–12 times more than in the course fractions. Since only the fine particles might be deposited in the deepest parts of the lung the importance of elimination of pollution sources should be taken into account.     

不同消解方法分析污泥中重金属含量的比较

采用三种电热板消解体系和两种微波消解体系分别对两种类型的污泥进行消解,并以电感耦合等离子体发射光谱法测定其中的Cu、Pb、Cr、Cd、Ni、Zn等11种金属的含量.结果表明,H2O2-王水-HF微波消解体系可实现污泥中重金属的充分溶解,对样品中Cu、Pb、Cr、Ni回收率可达96%~104%,相对标准偏差为0.16%~3.48%.该方法具有精密度好、准确度高、耗酸量少、操作安全简便等优点,适用于污泥中重金属的分析测定.     

Comparative analysis of sesquiterpene lactones from <Emphasis Type="Italic">Mikania cordifolia</Emphasis> collected from three different locations

The sesquiterpene lactone composition of extracts of Mikania cordifolia collected from Ribeirao Preto-SP (Brazil), Sao Carlos-SP (Brazil), and Campos de Jordao-SP (Brazil) were comparatively analyzed by HPLC. The results indicate that all specimens have the melampolide type sesquiterpene lactones analyzed and this kind of structure can be used as taxonomic marker for M. cordifolia. Published in Khimiya Prirodnykh Soedinenii, No. 2, pp. 117–118, March–April, 2007.     

Contact corrosion of metals in aqueous-glycolic solutions with high content of water

Corrosion behavior of aluminum, steel, and cast iron in aqueous-glycolic solutions containing 5 to 50 vol % was studied both in the absence of contact and in aluminum-steel, aluminum-cast iron, steel-cast iron, and aluminum-steel-cast iron contact systems.     

Heavy metals in lake water: a review on occurrence and analytical determination

Many lakes especially in Asia are source of livelihood for the surrounding communities. With increased urbanisation and industrialisation, however, these lakes are threatened with emerging environmental contaminants, including heavy metals. Some heavy metals are harmful to human health and the environment. This review aims to describe the different sampling, sample preparation and pretreatment, and instrumental methods of analysis for heavy metals in lake water. Filtration and acid digestion are common sample treatment methods used prior to analytical determination. Atomic absorption spectroscopy and inductively-coupled plasma – mass spectrometry (ICP-MS) are typical analytical techniques but nowadays ICP-MS is frequently used. This review also describes the sources and extent of heavy metals contamination in different lakes. Although some lakes still have natural levels of heavy metals in the water, many have elevated concentrations due to anthropogenic sources, such as vehicular, household, agricultural, industrial and mining activities.     

Determination by activation analysis of volatile metals and other elements in volcanic exhalations collected at Vulcano and Stromboli,Italy

Hot gases of volcanic origin (fumaroles) were sampled by means of an activated charcoal filter. The charcoal was specially prepared by a high temperature-vacuum treatment. Mercury, arsenic, bromine, antimony and selenium were determined by activation analysis and compared with literature values. A lightweight pumping station was developed to enable transport to the crater regions of Stromboli and Vulcano. The teflon membrane pump is driven by wind. The filter unit, a specially shaped quartz glass tube, was lowered into the hot vents. The temperature of the sampled fumaroles was 100 to 330°C.     

Heavy metals in marine sediments from the Mar Piccolo of Taranto (Ionian Sea, southern Italy)

Heavy metals concentrations (Cd, Cu, Hg, Pb, Sn and Zn) have been determined monthly in surface sediments from the Mar Piccolo in Taranto (Ionian Sea, Southern Italy. a semi-enclosed marine basin very important from a mussel-culture point of view. In sediments, sulphides, percentage of organic carbon and redox potential were also determined to show possible correlations between metals levels and redox characteristics of marine sediments. Analytical results, elaborated by multivariate statistical techniques, confirm that sediments collected in the first inlet of Mar Piccolo, where shipbuilding activities are present, have a contamination level greater than those collected in the second inlet. For each metal, the geoaccumulation index (Igeo) has been calculated as criterion to evaluate both pollution levels and metals enrichment in examined sediments: Igeo values confirm that the first inlet is an moderately polluted area from Hg and Pb. In any case, high sulphide concentrations and negative values of redox potentials bring to a conclusion that metals are present in sediments, mainly as insoluble sulphides and then as not bioavailable compounds for filter feeders organisms such as mussels.     

Heavy metals in PM10 sampled in the urban area of Campi Salentina (Apulia, southern Italy)

The following paper shows results of PM10 level and Cd, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn concentrations present in this fraction for filters collected in the urban area of Campi Salentina (Apulia, Southern Italy) in 2004 in order to inquire into air quality. PM10 and lead concentrations did not exceed the standard values sanctioned by Italian Legislature with average values equal to 36.54 +/- 14.57 microg x m(-3) and 9.19 +/- 5.24 ng x m(-3) respectively. Significant correlations have been found between the pairs Fe-Mn, Ni-V, Cr-Ni and Cd-Cr. This suggests that these metals have a similar pollution source probably due to metallurgical activity. Multivariate statistical analysis showed that it is possible to distinguish the PM10 samples collected in sampling periods with different meteorological conditions. Indeed, metals concentration increases for samples characterized by scarce rains or by winds prevailing from North or North-West and is reduced due to different meteorological conditions, although there are some exceptions.     

Heavy metals in human urinary calculi

Summary Heavy metals are incorporated in human urinary calculi during a complex pathological process. The trace metals cadmium, lead, chromium, nickel and mercury are determined with regard to significance in pathogenesis and therapy. The amounts of cadmium, lead and chromium were determined as well directly in the solid sample as after chemical digestion by Zeeman-GFAAS. Both analyzing techniques show corresponding results. Nickel could be determined after chemical digestion only, while mercury was determined by a solid sampling technique. The evaluation of the results of trace metal analysis in the pilot study of 11 urinary calculi showed increased amounts of lead and cadmium compared to the results of tartar and salivary calculi.     

Levels of artificial radionuclides and uranium in rain water collected from Ibaraki (Japan) following the Tomsk-7 accident in Russia

Measurements of some selected radionuclides were carried out in rain waters collected from Ibaraki Prefecture, Japan, following the nuclear accident at Tomsk-7, Russian Federation, in April 1993. The concentrations obtained for artificial radionuclides were⁹⁰Sr1.8 mBq l^–1,¹³⁷Cs0.1 Bq l^–1,¹³¹I0.1 Bq l^–1 and¹²⁹I4 Bq l^–1. Uranium (²³⁸U) concentrations in rainfalls in April 1993 were 6.3–39 ng l^–1. These data were compared to control values obtained previously and there was no appreciable influence on the radioactivity levels in Japan after the Tomsk-7 accident. Since only limited data on the concentrations of¹²⁹I and uranium in rain water are available, these new analytical results contribute to understanding the background levels for these nuclides.     

Heavy metals as toxicants in big cities

Heavy Metals (HMs) can exert detrimental effects on human health and on the environment. Their ecotoxicological properties are generally well known. As regards human toxicology, new aspects should be taken into consideration—gender and age dependence. The HMs chemical risk can be estimated and in this context, city demography data help to evaluate today's ecological situation (including HMs) and to predict the dynamics of future urbanization.As regards urban atmosphere, motor vehicles (Pb) and industry (V, Ni, Cr, Cd) exert the greatest influence; water, soil, vegetation also experience menace caused by HMs. Urban environments should be protected against contamination posed by HMs: the health status of big cities is dependent on adequate and safe supply of water. Vegetation plays a helpful role in reducing HM content in the atmosphere and the soil. Awareness of the inhabitants regarding the risks posed by HMs also counts as critical factor today. Ecoeducation at the beginning of the new century can be taken into consideration.     

Heavy metals contamination in roadside soil near different traffic signals in Dubai,United Arab Emirates

The present research was conducted to study heavy metal contamination in roadside soil viz. (i) at sites having more than two traffic signals (ii) roads having only one traffic signal and (iii) roads having no traffic signals. The samples were collected and analyzed for seven heavy metals i.e. cadmium (Cd), lead (Pb), copper (Cu), nickel (Ni), iron (Fe), manganese (Mn) and zinc (Zn) by Atomic Absorption Spectroscopy (AAS) following the acid digestion of the respective soil samples. The range of the metals observed in soil having more than two traffic signals were Cd (0.17–1.01), Pb (259.66–2784.45), Cu (15.51–65.90), Ni (13.31–98.13), Fe (325.64–5136.37), Mn (57.95–166.43), and Zn (91.34–166.43) mg kg^?1 respectively. Similarly, the range of metals analyzed in samples collected from the roadside having only one traffic signal were Cd (nd–0.80), Pb (145.95–308.09), Cu (0.82–18.04), Ni (18.29–59.36), Fe (88.51–3649.42), Mn (25.88–147.34) and Zn (8.97–106.11 mg kg ^?1) respectively. However, the range of metals at roads having no traffic signals were Cd (0.0–0.57), Pb (8.34–58.20), Cu (2.88–5.81), Ni (3.34–73.80), Fe (55.34–332.81), Mn (2.98–98.73) and Zn (1.23–46.6 mg kg^?1) respectively. Cd, Cu, Ni, Fe, Mn and Zn in soil were present within the normal range of background levels, whereas lead was reported in high concentration. The level of lead had a correlation with the traffic density attributing its origin to vehicular exhaust. The values from three different sites of monitoring suggest that automobiles are a major source of the studied metals for the roadside environment.     

Heavy metals in petroleum-contaminated surface soils in Serbia

Investigation of heavy metal contamination levels as well as their association types with substrates in petroleum-contaminated surface soil was carried out using modified sequential extraction method. In that way, remobilization capacity of metal cations, both in natural conditions and in accidents, has been studied. Moreover, partitioning of heavy metals, originating from spilt oil derivative, among surface soil substrates was estimated. Extreme contamination with lead was discovered, as well as the increased concentrations of zinc and copper. Oil-derived Pb and Zn were found to be distributed between carbonates and amorphous Fe-oxides, whereas Cu was found to be dominantly associated with amorphous Fe-oxides. Appreciable amounts of these metals were also found to be incorporated into more resistant structures. In petroleum-contaminated surface soil, substrates of cadmium are carbonates, whereas nickel has the great affinity toward hydrous Mn-oxides. Cd is proven to be the most mobile metal in oil-contaminated surface soil.