Estimation of Polish cigarettes contamination with cadmium and lead, and exposure to these metals via smoking

To estimate exposure to cadmium (Cd) and lead (Pb) through cigarette smoking, the concentrations of both metals in the blood or/and urine of smokers (20 cigarettes or more per day for 10 years or longer) and their non-smoking counterparts inhabiting an environmentally unpolluted area (Bialystok, Poland) were evaluated, as well as Cd and Pb contents in the cigarette brands (produced in Poland) smoked by the participants, including intact cigarettes, pre-smoking (tobacco, paper and filter) and post-smoking (butt, ash and smoke) cigarette components. Blood and urinary Cd concentrations in the smokers have been already reported by us to be 2–4 times higher than in the non-smokers (Galażyn-Sidorczuk et al. Polish Journal of Environmental Studies, 13 (Suppl.1):91–95, 2004). All the other measurements are the subject of the present paper. Pb concentration in the blood of the cigarette smokers (52.12 ± 15.51 μg l⁻¹) was higher by 29% than in the non-smokers (40.42 ± 11.19 μg l⁻¹). The mean Cd and Pb contents in the cigarettes were 0.6801 ± 0.1765 and 0.6853 ± 0.0746 μg per cigarette, respectively. Under cigarette burning, performed using a machine for self-acting burning, on average 33% of Cd and 11% of Pb present in the whole cigarette was released into the smoke. For Cd, unlike Pb, there was a high positive correlation between the metal content in cigarettes and tobacco and its release into the smoke. Moreover, the subjects smoking cigarettes containing the highest Cd amount had higher blood Cd concentration than smokers of other cigarette brands. The results give clear evidence that in the case of inhabitants of areas unpolluted with Cd and Pb habitual cigarette smoking, due to tobacco contamination, creates a serious source of chronic exposure to these metals, especially to Cd.     

利用自动采样滤膜监测PM_(2.5)中铅和镉的可行性

根据PM2.5中重金属监测国标分析方法,从PM2.5采样方法、采样保存条件、滤膜材质性能等方面说明利用空气自动采样滤膜监测PM2.5中铅和镉是可行的;对手工采样(石英滤膜)和Beta射线法自动采样(自动采样滤膜)2种方法,对PM2.5实际样品中铅和镉的结果进行比较,结果显示:自动采样滤膜的空白检出和检出限均满足铅和镉的监测需求,铅和镉的回收率分别为95.2%~107%和91.8%~105%,与手工采样方法相比测得铅和镉的相对误差分别为3.6%~8.4%和1.3%~10.8%,从实践角度进一步证明了利用自动采样滤膜对PM2.5中铅和镉进行监测是可行的。     

Determination of Pb and Cd in road dusts over the period in which Pb was removed from petrol in the UK

It is commonly agreed that automobile exhaust has been the most important source of Pb pollution in urban areas, and that Cd may come from wear and tear of tyres. This study evaluates the fall in Pb concentrations in road dusts in Manchester as a consequence of the removal of Pb from petrol in January 2000. In the work presented here a slurry graphite furnace atomic absorption methodology for the determination of Pb and Cd in road dusts has been developed and is compared with an acid digestion method in terms of efficiency. The reproducibility and accuracy of the results obtained by acid digestion and the slurry method have been studied and a certified reference material CRM 038 was analysed to confirm the reliability of the proposed methods. Different factors were evaluated throughout this work including: (i) the effect of traffic density on Pb and Cd levels in road dust samples collected weekly during the period of May 1999 until September 2000; (ii) comparison between the Pb and Cd levels in a busy road and a residential street; (iii) the effect of distance from the source on Pb and Cd levels; The results of these experiments show a reduction in Pb levels over the sampling period. The relationship between road dust particle size and Pb and Cd concentration was also investigated in the 4-250 microns size range using the slurry method, showing that there is a relationship between metal concentration and particle size; the highest concentrations being for the smallest particle size.     

高压密闭消解土壤砷、汞、铅、镉酸体系比较

采用高压密闭消解系统消解土壤,氢化物发生-原子荧光光谱法(HG-AFS)测定As和Hg,石墨炉原子吸收光度法(GF-AAS)测定Pb和Cd,对比了不同消解酸体系对国家土壤标准参考样中As、Hg、Pb、Cd的消解效果。结果表明,盐酸-硝酸体系对As、Hg、Pb和Cd的消解平均回收率分别为26.1%、100.6%、69.7%、87.3%;硝酸-高氯酸-氢氟酸体系中As、Hg、Pb和Cd消解平均回收率分别为109.9%、84.7%、87.5%、90.1%;硝酸-双氧水体系对Hg、Pb、Cd消解平均回收率分别为104.8%、95.1%、93.3%,对As的回收率虽只有69.2%,但数据精密度最好。此外,从简化试验步骤,减少误差,提高检测效率及减少试验危险性等方面综合评价,认为硝酸-双氧水消解体系是采用高压密闭系统消解土壤重金属的最理想酸体系。     

The effect of filter material on bioaerosol collection of Bacillus subtilis spores used as a Bacillus anthracis simulant

The objective of this study was to determine filter materials and extraction methods that are appropriate to use for environmental sampling of B. anthracis. Four types of filters were tested: mixed cellulose ester (MCE) with a pore size of 3 microm, polytetrafluoroethylene (PTFE) with pore sizes of 1 and 3 microm, and gelatin with a pore size of 3 microm. Bacillus subtilis var. niger endospores (also known as Bacillus globigii[BG]) were used as a surrogate for B. anthracis. Endospores were collected into Button Inhalable Aerosol Samplers with sampling times of 15 minutes, 1 hour, and 4 hours. Physical collection efficiency was determined by measuring upstream and downstream B. subtilis concentrations with an optical particle counter. Vortexing with ultrasonic agitation and vortexing with shaker agitation extraction methods were evaluated. The MCE, 1 microm PTFE, and gelatin filters provided physical collection efficiencies of 94% or greater. The 3 microm PTFE filter showed inconsistent physical efficiency characteristics between filters. Epifluorescence microscopic analysis of the gelatin filter extraction fluid revealed the presence of contamination by non-culturable bacteria. Mean differences for microbial culturability were not statistically significant for filter materials and extraction methods. However, the vortexing with shaker agitation extraction method resulted in higher total microbial counts in the extraction fluids for MCE and 1 microm PTFE filters when compared to vortexing with ultrasonic agitation. In summary, the MCE and 1 microm PTFE filters in combination with vortexing and shaker extraction demonstrated the best performance for the filter collection and extraction of BG spores.     

Paleolimnological assessment of Grove and Plow Shop Ponds, Ayer, Massachusetts, USA--a superfund site

Three sediment cores from each of severely polluted Grove and Plow Shop Ponds, Ayer, Massachusetts, USA, were dated using (210)Pb, characterized for plant macrofossil assemblages, and analyzed for H(2)O, loss-on-ignition, stable Pb isotopes, and concentrations of As, Ca, Cd, Cr, Cu, Fe, Hg, methyl-Hg, Ni, Pb, and Zn. A core from nearby kettle Spectacle Pond, Littleton, Massachusetts, was similarly characterized (except for plant macrofossil assemblages) to assess the regional air pollution signal in sediment for comparison with the six cores. Accumulation rates for metals (mass per area per year), the anthropogenic component (mass per area per year), and total accumulation of the anthropogenic component (mass per area) indicate that As, Cd, Cr, Cu, Hg, methyl-Hg, Ni, Pb, and Zn have accumulated in sediment as a consequence of point source pollution from within the drainage basins of Grove and Plow Shop Ponds. Three distinct sources of pollution are inferred. As is entering Plow Shop Pond via groundwater in the southwest. Cd, Ni, Pb, and Zn are entering the system predominantly at the eastern end of, or upstream from, Grove Pond. Pb also comes from the northwest corner of Grove Pond, the principal source of Cr, Cu, and Hg. These results are consistent with chemistry of modern surface sediments. The history of pollution extends back more than 100 years. Intra- and inter-core variability of concentrations and accumulation rates indicate that much of the pollution was likely in particulate form with little physical redistribution. Recently, concentrations and accumulation rates have generally decreased substantially for those elements present in excessive concentrations in the past. This is a consequence of accumulation of recent, less polluted sediment. In Spectacle Pond, the nearby reference lake, accumulation rates for As, Cd, Hg, and Pb, adjusted for background values and changes in sedimentation rate, increased above background starting in the late 19th century, peaked about 1980, and declined substantially to 2000. These decreases suggest that the anthropogenic (pollution) component of atmospheric deposition of these elements declined after 1980 by at least 50%(As), 80%(Cd), 80%(Hg), and 80%(Pb).     

湖南省某冶炼厂周边农田土壤重金属污染及生态风险评价

利用野外采样与实验室分析相结合的方法,以湖南省某冶炼厂周边农田土壤(0~20 cm)为研究对象,监测了Cd、As、Pb、Cr、Cu、Zn、Hg等7种重金属的含量,并对重金属污染程度与潜在生态风险进行了评价。结果表明,7种重金属都存在不同程度的超标或污染,其中Cd、As、Pb等的污染较为严重。统计学分析结果表明,Pb、As、Hg、Zn、Cd等来源相同,可能主要都来自于人为污染,即冶炼作业造成的污染。7种重金属化学形态不尽相同:在重金属有效态中,Cd的水溶态和可提取态较高;Pb、Cu、Zn可还原态、可氧化态这两部分含量较高。而Hg、As、Cr的残渣态含量较高。风险评价代码评价结果表明,Cd的生态风险较高,4.5%的样点Cd为极高生态风险,52.8%的样点Cd为高生态风险,42.7%的样点Cd为中度生态风险;100%的样点Zn为中度生态风险;Cu有60.1%的样点属于低生态风险,39.9%的样点属于中度生态风险;As、Pb主要以低生态风险为主(所占比例分别为77.2%、80%);Hg主要以无生态风险为主(所占94.3%)。Hakanson潜在生态风险指数法计算的综合潜在生态风险指数(RI)的范围为46.4~1 627.5,表明研究区域农田土壤存在很高的生态风险。上述各项结果综合表明,研究区农田土壤受到了严重的重金属污染,由此引起的重金属生态风险应引起高度关注。     

再生铅企业土壤-地下水中重金属污染迁移特征

为了解某再生铅企业厂区土壤和浅层地下水重金属污染状况,采集了96个土壤样品和4个地下水样品,定量分析了其Pb,Cd,As的含量及空间分布特征,探讨企业生产对环境造成的影响。结果表明,该区域土壤中Cd、As、Pb超标率分别为67.0%,35.1%,11.7%,在厂区呈现局部富集现象,最大值是土壤背景值的几十倍乃至数千倍;在垂直方向上由于Pb,Cd,As在土壤中迁移率较低,其值随深度增加呈总体下降趋势;该区域地下水中Pb,Cd,As值远低于地下水质量标准值。     

Trace metal speciation during dry and wet weather flows in the Tama River, Japan, by using diffusive gradients in thin films (DGT)

The labile species of Ni, Cu, Zn, Cd, and Pb in the Tama River, an urban river in Tokyo, Japan, were measured using diffusive gradients in thin films (DGT) method under dry and wet weather conditions, and the results were compared with total dissolved concentrations in hourly samples collected in parallel. A total of 10 DGT deployments were made and 251 hourly samples were collected during 2 rounds of sampling, conducted between August and October, 2006. Two types of diffusive gradients in thin films (DGT) devices-DGT-RG for labile inorganic and DGT-APA for total (inorganic and organic) labile species-were applied throughout the samplings. The proportions of metals measured by DGT, compared with the dissolved metal concentrations (filtered using a membrane of 0.5 microm pore size), were 38 +/- 5% (RG) and 45 +/- 8% (APA) for Ni and 45 +/- 22% (RG) and 53 +/- 23% (APA) for Zn. No labile Cu was detected throughout the sampling; Cu was assumed to be in stable complexed forms. Labile Pb was detected in 3 out of 10 deployments only; the rest were lower than the detection limit. Dissolved and labile Cd concentrations were below the detection limits. Three rain events encountered during the sampling periods were evaluated. Rains brought considerably higher loads of metals in dissolved form, and DGT measurements indicated that labile metal loads also increased. Selected DGT measurements were compared with the WHAM 6 speciation model and found to be similar to the model-computed results.     

Triethoxysilyl-substituted aminoethanethiol ligands for zinc and cadmium complexes and aminoethanethiol-modified silica gel. Evaluation of the corresponding supported molecular trap for metallic pollutant uptake (Cd2+, Hg2+ and Pb2+)

The reaction of 2-[3-(triethoxysilyl)propylamino]ethanethiol (LH, a) and 1-methyl-2-[3-(triethoxysilyl)propylamino]ethanethiol (LH, b) with ZnX2 and CdX2 (X = Cl, Br, I, NO3) in tetrahydrofuran (THF) or CH2Cl2 gives several complexes depending on the experimental conditions. Elemental analyses, IR, Raman, 13C[1H], 1H NMR and mass spectroscopies indicated the formation of mononuclear and dinuclear complexes. In the absence of NEt3 as proton quencher, the protonated ligands react in their zwitterionic form giving dinuclear [M(LH)X2]2 [M = Zn (1), Cd (2); LH = a, b; X = Cl, Br, I] or mononuclear M(NO3)2(LH)2 [M = Zn (5), Cd (6); LH = a] complexes. In both cases, coordination occurs through the S atoms, the ligands acting as terminal and bridging species. With NEt3, the deprotonated ligands are chelated through their N and S atoms and bridging occurs through the S atoms in [MLX]2 [M = Zn (3), Cd (4); LH = a; X = Cl, Br] complexes. The LH ligand is chemically grafted onto silica, the procedure optimized and the resulting material characterized by 13C and 29Si cross-polarization, magic-angle spinning (CP-MAS) NMR and DRIFT. This material is evaluated as a supported molecular trap for binding heavy metals (Cd2+, Hg2+, Pb2+) in aqueous solution. In both batch and column processes, it appears that Hg2+ and Pb2+ are trapped more than Cd2+, but in all cases values lower than those allowed were obtained.     

Spatial distribution,temporal variation,and sources of heavy metal pollution in groundwater of a century-old nonferrous metal mining and smelting area in China

This study first presents the spatial distribution, temporal variation, and sources of heavy metal pollution in groundwater of a nonferrous metal mine area in China. Unconfined groundwater was polluted by Pb, Zn, As, and Cu, in order, while confined karst water in the mines showed pollution in the following sequence: Zn, Cd, Cu, Pb, and As. Pollution by Pb was widespread, while Zn, As, Cu, and Cd were found to be high in the north–central industrial region and to decrease gradually with distance from smelters and tailings. Vertically, more Pb, Zn, Cu, and Cd have accumulated in shallow Quaternary groundwater, while more As have migrated into the deeper fracture groundwater in the local discharge area. Zn, Cd, and Cu concentrations in groundwater along the riverside diminished owing to reduced wastewater drainage since 1977, while samples in the confluence area were found to have increasing contents of Pb, Zn, As, Cu, and Cd since industrialization began in the 1990s. Sources of heavy metals in groundwater were of anthropogenic origin except for Cr. Pb originated primarily from airborne volatile particulates, wastewater, and waste residues and deposited continuously, while Zn, Cd, and Cu were derived from the wastewater of smelters and leakage of tailings, which corresponded to the related soil and surface residue researches. Elevated As values around factories might be the result of chemical reactions. Flow patterns in different hydrogeological units and adsorption capability of from Quaternary sediments restricted their cross-border diffusion.     

The application of ICP-SMS, GF-AAS and HG-AFS to the analysis of water and sediment samples from a temperate stratified estuary

Three atomic spectrometry techniques, namely sector field inductively coupled plasma mass spectroscopy, graphite furnace atomic absorption spectrometry and hydride generation atomic fluorescence spectroscopy (ICP-SMS, GF-AAS and HG-AFS, respectively), housed at separate independent laboratories, were used to analyse water and sediment samples collected from the Huon River Estuary, SE Tasmania (Australia) in the Austral spring 1998. A dithiocarbamate-chelation/back-extraction technique was used to separate and preconcentrate Co, Ni, Cu, Zn, Cd and Pb from eight collected water samples prior to analysis by ICP-SMS and GF-AAS. A number of other elements in the waters were analysed directly (Mn, Fe and Zn by GF-AAS; As by HG-AFS), or following sample dilution (1 + 19: V, Mn, Fe, As, Mo, Ba and U by ICP-SMS). Where possible, previously corroborated GF-AAS and HG-AFS techniques were used to verify obtained ICP-SMS results. From the analysis of four reference waters (SLEW-1 and -2, SLRS-3 and NASS-5), good agreement, to within +/- 10-20%, was typically found between certified (or information only values) and measured results (irrespective of analytical technique). Exceptions included Zn (and sometimes Fe) that could not be quantified by ICP-SMS due to elevated blank signals, and As which was found to lie below ICP-SMS detection limits. For Huon Estuary water samples, inter-method agreement was within +/- 10-20% (for those elements amenable to analysis by more than one technique). Nitric acid extracts of two certified reference materials (Buffalo River Sediment and BCSS-1) and six Huon Estuary sediments were analysed by ICP-SMS (for Al, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd and Pb) and HG-AFS (for As). Results from the certified reference materials indicated extraction efficiencies of 60 70% (for most elements). A close correlation between ICP-SMS and HG-AFS was obtained for leachable As in the sediments. In terms of potential inorganic contaminants, the Huon Estuary was found to be a relatively 'clean' water system. The elemental concentrations measured in water and sediment samples from this region were found to lie within current Australian guidelines for estuaries. In general, no one analytical technique was able to accurately determine all elements in all samples from this relatively pristine estuarine environment. A combination of all three analytical techniques was necessary for the successful analysis of the elements considered in this study.     

Cigarette smoking and nickel exposure

The tobacco plant contains nickel and several other toxic metals, most probably absorbed from the soil, fertilizing products or from pesticides. It has been stated that nickel in a burning cigarette might form the volatile, gaseous compound, nickel tetracarbonyl, and thereby be introduced into the respiratory tract. Accordingly, the main objective of the present study was to find out if nickel content in inhaled smoke from ordinary cigarettes and nickel-contaminated cigarettes handmade by nickel process workers might be a supplementary source of nickel exposure to cigarette smoking process workers leading to additional risk of occupational respiratory cancer in these workers. Blood and urine samples from 318 randomly selected employees from Falconbridge Nickel Refinery in Kristiansand, Norway, allocated to 197 smokers and 121 non-smokers, were analysed for nickel content. Nickel quantities in tobacco from various cigarette brands, from nickel-contaminated cigarettes made by process workers or from cigarettes added known amounts of various nickel salts were analysed before being smoked. The cigarettes were smoked in a smoking machine device applying an electrostatic filter. Blood and urine, tobacco, ash and precipitates in the filter from the main stream smoke of the cigarettes were analysed for nickel quantities by atomic absorption spectrometry methods as previously described by the authors. The nickel concentrations in blood plasma and urine were quite similar among smokers and non-smokers, 6.2 and 48.1 microg L(-1) in smokers, and 6.4 and 50.5 microg L(-1) in non-smokers respectively. We recovered 1.1% or even less of nickel in the mainstream smoke after smoking the entire cigarettes without leaving any butt. Most of the tobacco nickel was recovered in the ash. We conclude that the inhaled nickel in the working atmosphere is probably the main source of the nickel exposure to the respiratory tract in these workers. It remains to be determined why cigarette smoking still seems to be a decisive cofactor in the development of respiratory tract cancer in nickel workers.     

Assessment of heavy metals in sediments from a typical catchment of the Yangtze River, China

An intensive investigation was conducted to study the accumulation, speciation, and distribution of various heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in sediments from the Yangtze River catchment of Wuhan, China. The potential ecological risks posed by these heavy metals also were estimated. The median concentrations of most heavy metals (As, Cd, Cr, Cu, Ni, Pb, and Zn) were higher than the background values of soils in Wuhan and were beyond the threshold effect level (TEL), implying heavy metal contamination of the sediments. Carbonate-bound Cd and exchangeable Cd, both of which had high bioavailability, were 40.2% and 30.5% of the total for Cd, respectively, demonstrating that Cd poses a high ecological risk in the sediments. The coefficients of the relationship among Pb, Hg, and Cu were greater than 0.797 using correlation analysis, indicating the highly positive correlation among these three elements. Besides, total organic carbon content played an important role in determining the behaviors of heavy metals in sediments. Principal component analysis was used to study the distribution and potential origin of heavy metals. The result suggested three principal components controlling their variability in sediments, which accounted for 36.72% (factor 1: Hg, Cu, and Pb), 28.69% (factor 2: Cr, Zn, and Ni), and 19.45% (factor 3: As and Cd) of the total variance. Overall, 75% of the studied sediment samples afforded relatively low potential ecological risk despite the fact that generally higher concentrations of heavy metals relative to TEL were detected in the sediments.     

Determination of Cadmium and Lead in Different Cigarette Brands in Jordan

Cadmium (Cd) and lead (Pb) concentrations in different cigarette brands sold and/or produced in Jordan were determined by graphite furnace atomic absorption spectrometry (GF-AAS). Average levels of Cd and Pb in different cigarette brands in Jordan were 2.64 and 2.67 g g^{– 1} (DW), respectively. The results obtained in this study estimate the average quantity of Cd inhaled from smoking one packet of 20 cigarettes to be in the range of 3.65–7.30 g. Results suggest that the quantity of Pb inhaled of smoking one packet of 20 cigarettes, is estimated to be 0.74–2.22 g. The concentrations of Cd and Pb in cigarettes were significantly different between cigarette brands tested. Our results were compared with other worldwide studies.     

Development of a method for bacteria and virus recovery from heating, ventilation, and air conditioning (HVAC) filters

The aim of the work presented here is to study the effectiveness of building air handling units (AHUs) in serving as high volume sampling devices for airborne bacteria and viruses. An HVAC test facility constructed according to ASHRAE Standard 52.2-1999 was used for the controlled loading of HVAC filter media with aerosolized bacteria and virus. Nonpathogenic Bacillus subtilis var. niger was chosen as a surrogate for Bacillus anthracis. Three animal viruses; transmissible gastroenteritis virus (TGEV), avian pneumovirus (APV), and fowlpox virus were chosen as surrogates for three human viruses; SARS coronavirus, respiratory syncytial virus, and smallpox virus; respectively. These bacteria and viruses were nebulized in separate tests and injected into the test duct of the test facility upstream of a MERV 14 filter. SKC Biosamplers upstream and downstream of the test filter served as reference samplers. The collection efficiency of the filter media was calculated to be 96.5 +/- 1.5% for B. subtilis, however no collection efficiency was measured for the viruses as no live virus was ever recovered from the downstream samplers. Filter samples were cut from the test filter and eluted by hand-shaking. An extraction efficiency of 105 +/- 19% was calculated for B. subtilis. The viruses were extracted at much lower efficiencies (0.7-20%). Our results indicate that the airborne concentration of spore-forming bacteria in building AHUs may be determined by analyzing the material collected on HVAC filter media, however culture-based analytical techniques are impractical for virus recovery. Molecular-based identification techniques such as PCR could be used.     

Distribution and Fractionation of Heavy Metals in Solid Waste from Selected Sites in the Industrial Belt of Delhi, India

Solid waste samples were collected from five small-scale industrial sites in the National Capital Territory (NCT) of Delhi. These industrial sites represent the regional spread of the industrial belt in the NCT of Delhi. Solid waste samples were digested using aqua-regia and HF in air tight teflon bombs for the quantitative analysis of heavy metals (Hg, Pb, Cd, Mn, Fe, Ni, Cu and Zn) by GBC model 902 atomic absorption spectrophotometer. Hg was analysed using hydrid generator attachment. Beside this sequential extraction was used to fractionate five heavy metals (Pb, Ni, Cd, Cu and Zn) into six operationally defined phases, viz. water soluble, exchangeable, carbonate-bound, Fe-Mn oxides, organic-bound and residual fractions to ascertain the relative mobility of these metals. The result obtained showed metal concentration to be in the range of Hg 0.42-2.3; Pb 23-530; Cd 014-224; Mn 494-19 964; Fe 35 684-233 119; Ni 192-1534; Cu 3065-10 144 and Zn 116-23 321 (all units in mg kg(-1)) in all the industrial areas studied. The fractionated toxic metals like Pb, Ni and Cd were observed to be in the range of 25-35, 15-50 and 40-50%, respectively, in mobile or bio-available fractions of solid waste. As this waste is often disposed-off by the roadsides, low lying areas, abandoned quarries or in landfill sites which are often not properly planned, thus posing potential risk to ground and surface water quality to millions of people living downstream.     

Associations of cadmium, zinc, and lead in soils from a lead and zinc mining area as studied by single and sequential extractions

An exploratory study of the area surrounding a historical Pb?CZn mining and smelting area in Zawar, India, detected significant contamination of the terrestrial environment by heavy metals. Soils (n?=?87) were analyzed for pH, EC, total organic matter (TOM), Pb, Zn, Mn, and Cd levels. The statistical analysis indicated that the frequency distribution of the analyzed parameters for these soils was not normal. The median concentrations of metals in surface soils were: Pb 420.21 ?? g/g, Zn 870.25 ?? g/g, Mn 696.70 ?? g/g, and Cd 2.09 ?? g/g. Zn concentrations were significantly correlated with Cd (r?=?0.867), indicating that levels of Cd are dependent on Zn. However, pH, electrical conductivity and total organic matter were not correlated significantly with Cd, Pb, Zn, and Mn. To assess the potential mobility of Cd, Pb, and Zn in soils, single (EDTA) as well as sequential extraction scheme (modified BCR) were applied to representative (n?=?23) soil samples. The amount of Cd, Pb, and Zn extracted by EDTA and their total concentrations showed linear positive correlation, which are statistically significant (r values for Cd, Pb, and Zn being 0.901, 0.971, and 0.795, respectively, and P values being <0.001). The correlation coefficients indicate a strong relation between EDTA-extractable metal and total metal. These results appear to justify the use of ??total?? metal contents as a useful preliminary indicator of areas where the risks of metal excess or deficiency are high. The EDTA extractability was maximum for Cd followed by Pb and Zn in soils from all the locations. As indicated by single extraction, the apparent mobility and potential bioavailability of metals in soils followed the order: Cd ?? Pb >?> Zn. Soil samples were sequentially extracted (modified BCR) so that solid pools of Cd, Zn, and Pb could be partitioned into four operationally defined fractions viz. acid-soluble, reducible, oxidizable, and residual. Cadmium was present appreciably (39.41%) in the acid-soluble fraction and zinc was predominantly associated (32.42%) with residual fraction. Pb (66.86%) and Zn (30.44%) were present mainly in the reducible fraction. Assuming that the mobility and bioavailability are related to solubility of geochemical forms of metals and decrease in the order of extraction, the apparent mobility and potential metal bioavailability for these contaminated soil samples is Cd > Zn > Pb.     

Pollution, fractionation, and mobility of Pb, Cd, Cu, and Zn in garden and paddy soils from a Pb/Zn mining area

This study was conducted to investigate the pollution load index, fraction distributions, and mobility of Pb, Cd, Cu, and Zn in garden and paddy soils collected from a Pb/Zn mine in Chenzhou City, China. The samples were analyzed using Leleyter and Probst’s sequential extraction procedures. Total metal concentrations including Pb, Cd, Cu, and Zn exceeded the maximum permissible limits for soils set by the Ministry of Environmental Protection of China, and the order of the pollution index was Cd > Zn > Pb > Cu, indicating that the soils from both sites seriously suffered from heavy metal pollution, especially Cd. The sums of metal fractions were in agreement with the total contents of heavy metals. However, there were significant differences in fraction distributions of heavy metals in garden and paddy soils. The residual fractions of heavy metals were the predominant form with 43.0% for Pb, 32.3% for Cd, 33.5% for Cu, and 44.2% for Zn in garden soil, while 51.6% for Pb, 40.4% for Cd, 40.3% for Cu, and 40.9% for Zn in paddy soil. Furthermore, the proportions of water-soluble and exchangeable fractions extracted by the selected analytical methods were the lowest among all fractions. On the basis of the speciation of heavy metals, the mobility factor values of heavy metals have the following order: Cd (25.2–19.8%) > Cu (22.6–6.3%) > Zn (9.6–6.0%) > Pb (6.7–2.5%) in both contaminated soils.     

Near-real-time determination of hydrogen peroxide generated from cigarette smoke

The ability to monitor hydrogen peroxide (H2O2) in aqueous smoke extracts will advance our understanding of the relationship between cigarette smoke-induced oxidative stress, inflammation, and disease and help elucidate the pathways by which the various smoke constituents exert their pathogenic effects. We have demonstrated, for the first time, the measurement of H2O2 production from cigarette smoke without prior separation of the sample. Cigarettes were tested on a commercial smoking machine, such that the whole smoke or gas vapor phase was bubbled through phosphate buffered saline solution at pH 7.4. Aliquots of these solutions were analyzed using an Amplex Red/horseradish peroxidase fluorimetric assay that required only a 2 minute incubation time, facilitating the rapid, facile collection of data. Catalase was used to demonstrate the selectivity and specificity of the assay for H2O2 in the complex smoke matrix. We measured approximately 7-8 microM H2O2 from two reference cigarettes (i.e., 1R4F and 2R4F). We also observed 9x more H2O2 from whole smoke bubbled samples compared to the gas vapor phase, indicating that the major constituent(s) responsible for H2O2 formation reside in the particulate phase of cigarette smoke. Aqueous solutions of hydroquinone and catechol, both of which are particulate phase constituents of cigarette smoke, generated no H2O2 even though they are free radical precursors involved in the production of reactive oxygen species in the smoke matrix.