Mean Concentrations Of Pb Research Articles

Plant uptake of trace elements on a Swiss military shooting range: Uptake pathways and land management implications

Over 400 tons of Pb enters Swiss soils annually at some 2000 military shooting ranges (MSRs). We measured elements in the leaves of 10 plant species and associated rhizospheric soil on the stop butt of a disused MSR. The geometric mean concentrations of Pb, Sb, Cu, Ni in rhizospheric soils were 10,171 mg/kg, 5067 mg/kg, 4125 mg/kg and 917 mg/kg. Some species contained Pb, Cu and Ni, above concentrations (30 mg/kg, 25 mg/kg and 50 mg/kg) shown to be toxic to livestock. Most contaminants in leaves resulted from surface deposition. However, at soil Pb concentrations >60,000 mg/kg, Equisetum arvense and Tussilago farfara took up >1000 mg/kg Pb into the leaves. These plants are not hyperaccumulators, having <100 mg/kg Pb in leaves at lower soil concentrations. Removal of soil with more than 30,000 Pb, from which one could smelt this metal to offset remediation costs, followed by revegetation, would minimise dust and hence leaf-borne contaminants.

Association between the plasma/whole blood lead ratio and history of spontaneous abortion: a nested cross-sectional study

BackgroundBlood lead has been associated with an elevated risk of miscarriage. The plasmatic fraction of lead represents the toxicologically active fraction of lead. Women with a tendency to have a higher plasma/whole blood Pb ratio could tend towards an elevated risk of miscarriage due to a higher plasma Pb for a given whole blood Pb and would consequently have a history of spontaneous abortion.MethodsWe studied 207 pregnant Mexico City residents during the 1st trimester of pregnancy, originally recruited for two cohorts between 1997 and 2004. Criteria for inclusion in this study were having had at least one previous pregnancy, and having valid plasma and blood Pb measurements. Pb was measured in whole blood and plasma by inductively coupled plasma mass spectrometry using ultra-clean techniques. History of miscarriage in previous pregnancies was obtained by interview. The incidence rate of spontaneous abortion was defined as the proportion of previous pregnancies that resulted in miscarriage. Data were analyzed by means of Poisson regression models featuring the incidence rate of spontaneous abortion as the outcome and continuous or categorized plasma/blood Pb ratios as predictor variables. All models were adjusted for age and schooling. Additionally, logistic regression models featuring inclusion in the study sample as the outcome were fitted to assess potential selection bias.ResultsThe mean number of miscarriages was 0.42 (range 0 to 4); mean Pb concentrations were 62.4 and 0.14 μg/L in whole blood and plasma respectively. Mean plasma/blood Pb ratio was 0.22%. We estimated that a 0.1% increment in the plasma/blood Pb ratio lead was associated to a 12% greater incidence of spontaneous abortion (p = 0.02). Women in the upper tertile of the plasma/blood Pb ratio had twice the incidence rate of those in the lower tertile (p = 0.02). Conditional on recruitment cohort, inclusion in the study sample was unrelated to observable characteristics such as number of abortions, number of pregnancies, blood Pb levels, age schooling, weight and height.ConclusionWomen with a large plasma/whole blood Pb ratio may be at higher risk of miscarriage, which could be due to a greater availability of placental barrier-crossing Pb.

Abandoned mine sites as a source of contamination by heavy metals: A case study in a semi-arid zone

Mining and milling operations, including grinding, concentrating ores and disposal of tailings, along with mine and mill waste water, provide obvious sources of contamination in the surface environment. Climatic effects such as heavy rainfall events, have a great impact in the dispersion of metals in semi-arid areas, since soils are typically scarcely vegetated. The dispersion and influence of soluble and particulate metals present in the materials from an abandoned mine, Cabezo Rajao, in SE Spain, was evaluated. Tailings and soils were sampled and analysed for pH, EC, CaCO 3, grainsize, mineralogical composition and heavy metal content, while water samples were collected and analysed for pH, EC, soluble metals and salts. The mean concentrations of Pb, Zn, Cd, Cu and As in solid samples were 8.3 g kg − 1 , 12.5 g kg − 1 , 40.9 mg kg − 1 , 332.1 mg kg − 1 , 314.7 mg kg − 1 respectively, and 1.5 mg l − 1 , 50.3 mg l − 1 , 13.6 g l − 1 , 17.2 mg l − 1 , 1.7 mg l − 1 in water samples respectively. These metals can be dispersed downstream and downslope from the tailings by water after rainfall. Soil samples collected in the surroundings of Mar Menor Lagoon were analysed, reflecting the influence of the transport of soluble and particulate materials from Cabezo Rajao, especially of Pb and Zn. However, the presence of high amounts of carbonate in the soils around the mine area revealed the stabilization of all the metals studied.

Trace Element Concentrations in Livers of Polar Bears from Two Populations in Northern and Western Alaska

Concentrations of 20 trace elements (V, Cr, Mn, Co, Cu, Zn, Rb, Sr, Mo, Ag, Cd, In, Sn, Sb, Cs, Ba, Hg, Tl, Pb, and Bi) were measured in livers of polar bears (Ursus maritimus) collected from Northern and Western Alaska from 1993 to 2002 to examine differences in the profiles of trace metals between the Beaufort Sea (Northern Alaska) and the Chukchi Sea (Western Alaska) subpopulations in Alaska. Among the trace elements analyzed, concentrations of Cu (50-290 microg/g, dry wt) in polar bear livers were in the higher range of values that have been reported for marine mammals. Concentrations of Hg in polar bears varied widely, from 3.5 to 99 microg/g dry wt, and the mean concentrations in polar bears were comparable to concentrations reported previously for several other species of marine mammals. Mean concentrations of Pb and Cd were 0.67 and 1.0 microg/g dry wt, respectively; these concentrations were lower than levels reported elsewhere for polar bears from Greenland and Canada. Age- and gender-related variations in the concentrations of trace elements in our polar bears were minimal. Concentrations of Hg decreased slowly in samples collected during 1993-2002, whereas Cd and Pb concentrations were found to be stable or slowly increasing, in the livers of Alaskan polar bears. Concentrations of Ag, Bi, Ba, Cu, and Sn were significantly higher in the Chukchi Sea subpopulation than in the Beaufort Sea subpopulation. Concentrations of Hg were significantly higher in the Beaufort Sea subpopulation than in the Chukchi Sea subpopulation. Differences in the profiles and concentrations of Hg, Ag, Bi, Ba, Cu, and Sn suggest that the sources of exposure to these trace elements between Western and Northern Alaskan polar bears are different, in agreement with findings reported earlier for several organic contaminants.

Concentrations of heavy metals in urban soils of Talcahuano (Chile): a preliminary study

Concentrations of Cd, Cr, Ni, Pb, and Zn in the top-(0-10 cm) and sub-surface (10-20 cm) soils of the Talcahuano urban area were measured. The main soil properties (organic matter, CaCO3, pH, particle sizes) were determined for a network of representative sampling sites. The mean Cr, Ni, Pb, and Zn contents in the urban topsoil samples from Talcahuano (37.8, 22.6, 35.2, 333 mg kg(-1), respectively) were compared with mean concentrations for other cities around the world. The results revealed higher concentrations of heavy metals in topsoil samples than in sub-surface samples. The samples from IS1, IS2, and IS3, located in the Talcahuano industrial park, had higher Cr, Ni, Pb, and Zn contents than did samples from the other sites. This was probably due to local pollution by industrial (metallurgical) dust, although other diffuse pollution throughout the entire port region (shipyards, metallurgy, the dismantling of old ships), and contributions from the wind from adjacent industrial, storage, and vessel areas clearly played a role. Heavy metals were lowest in the sample taken on school grounds (SG).

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 (Galazyn-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 microg l(-1)) was higher by 29% than in the non-smokers (40.42 +/- 11.19 microg l(-1)). The mean Cd and Pb contents in the cigarettes were 0.6801 +/- 0.1765 and 0.6853 +/- 0.0746 microg 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.

Heavy‐Metal Concentration of Sewage‐Contaminated Water and Its Impact on Underground Water, Soil, and Crop Plants in Alluvial Soils of Northwestern India

Heavy‐metal concentration in underground and surface water, soil, and crop plants growing in farmers' fields near the industrial city of Ludhiana, Punjab, India, that receive irrigation with water contaminated with sewer and untreated industrial effluents was studied. The concentrations of lead (Pb), chromium (Cr), cadmium (Cd), and nickel (Ni) in sewage‐contaminated water were 18, 80, 88, and 210 times higher than in shallow handpump water, and 21, 133, 700, and 2200 times higher than in deep tube‐well water, respectively. The concentrations of Cd and Ni in shallow handpump underground water were significantly higher than in deep tube‐well underground water. The concentrations of Pb, Cr, Cd, and Ni in deep tube‐well water were 0.017, 0.003, 0.0002, and 0.0002 mg L−1, respectively. Soils irrigated with sewage‐contaminated water had higher electrical conductivity, cation exchange capacity, organic carbon (C), and clay content but had lower pH and calcium carbonate content compared to soils irrigated with deep underground water. The concentrations of diethylenetriamine pentaacetic acid (DTPA)–extractable Pb, Cr, Cd, and Ni in soils irrigated with sewage‐contaminated water were 1.8, 35.5, 3.6, and 14.3 times higher, and total concentrations of these heavy metals were 1.5, 3.0, 3.7, and 2.2 times higher than that in soils irrigated with deep underground water. The mean concentrations of Pb, Cr, Cd, and Ni in crop plants growing on soils irrigated with sewage‐contaminated water were 4.88, 4.20, 0.29, and 3.99 mg kg−1, which were 1.2, 2.1, 8.7, and 1.9 times higher than in plants irrigated with deep tube‐well water, respectively. The amounts of potentially toxic metals were significantly and positively correlated with cation exchange capacity and organic C content and negatively correlated with soil pH. In conclusion, long‐term accumulation of toxic metals in soils and their uptake by crop plants has a high potential for phytotoxicity as well as for entering into the food chain. The findings also suggest contamination of underground shallow drinking water through leaching of some highly mobile metals.

Deer exposed to exceptionally high concentrations of lead near the continental mine in idaho, USA

Habitat surrounding the inactive Continental Mine in northern Idaho, USA, supports bear (Ursus arctos, Ursus americanus), moose (Alces alces), elk (Cervus elaphus), woodland caribou (Rangifer tarandus caribou), and abundant mule (Odocoileus hemionus) and white-tailed deer (Odocoileus virginianus). Tailings on the mining site were capped and remediated in 2003 to reduce environmental exposure of surrounding soil and sediments of Blue Joe Creek, downslope of the mine. Before capping, the mean Pb concentration in deer pellets collected on-site was 920 mg/kg of Pb (dry wt). This exposure, if chronic, would be comparable to an exposure that could be lethal to cattle or horses. Surprisingly, the mean pellet Pb concentration of 950 mg/kg in 2004 was as high as it was before remediation, and it was related to a high rate of soil ingestion. Mean soil content of the pellets collected from the capped site in 2004 was 22% dry weight, estimated from the acid-insoluble ash, a marker of soil ingestion. Clumps of sand and bits of rock were observed inside some of the pellets, and Pb concentrations in the pellets were correlated (p < 0.05) with soil content. Although terrestrial risk assessments generally estimate exposure from diets and from incidentally ingested soil. the deer at this site were directly ingesting contaminated soil or mining waste. The mean Pb concentration of this ingested soil was estimated as 6,700 mg/kg and the maximum as 25,000 mg/kg, well above the Pb concentrations measured in the remediated cap. The deer seemed to be ingesting soil or mining waste from one or more small but highly contaminated sources located beyond the remediated cap.

The Impact of Lead Air Pollution Decrease on Human Exposure

P-689 Introduction: The aim of this work was to evaluate the impact of Pb air pollution decrease during the last two decades on human exposure to lead. Methods: During the period of 1997–2003 we analyzed Pb concentrations in approximately 400 samples of each of the following biological materials: placenta, umbilical cord blood, breast milk, blood of children and adults. Pb concentrations were measured by GFAAS. Together with the previous data found in our country, we compared our results with data for Pb concentrations in ambient air in the period of 1990–2001 reported by the Meteorological Synthesizing Centre-East of EMEP. We did the same comparison for Pb concentrations in biological materials and ambient air reported in Germany, Poland, and the Czech Republic. Results: During the period of 1990–2001, the mean annual Pb ambient air concentration in our country decreased from 32.7 to 9.8 ng/m3 (i.e. by 70.0%). Mean Pb concentrations in the studied biological materials decreased from 6.3 ug/kg in 1992 to 4.7 ug/kg in 1998 (by 25.4%) in human milk; from 41.9 ug/kg in 1987 to 25.6 ug/kg in 1998 (by 38.9%) in human placenta; from 61.1 ug/l in 1987 to 19.5 ug/l in 1998 (by 68.2%) with no other decline in 2003 (20.8 ug/l) in umbilical cord blood; from 86.6 ug/l in 1987 to 29.3 ug/l in 2003 (by 66.2%) in maternal blood; and from 36.9 ug/l in 1997 to 25.0 in 2003 (by 32.2%) in children's blood. The very similar trends were found also in the other three countries: the decrease of mean Pb concentrations in ambient air by 59.5–77.9% and in the biological materials by 19.1–40%. Discussion and Conclusions: Lead concentration in ambient air in Central European countries in the last 20 years significantly declined as a result of phasing out leaded gasoline, measures of air pollution policy, and also contraction of economic activities. This decline significantly reflected in human exposure to lead. Pb concentrations in different biological materials in the four studied countries decreased by 19–68%. We can conclude that this decreasing trend is very positive, especially concerning Pb exposure of children, who are very vulnerable to Pb, because even as low Pb concentration in their blood as 40 ug/l can have adverse effects on their neuromotor and cognitive performance. Acknowledgement: This study was supported by the Slovak Science and Technology Assistance Agency grants (APVT-21-025602, APVT-21-016504) and the Ministry of Health of the Slovak Republic grant (2005/41-SZU-19).

Determination of lead and cadmium contents of dry cell batteries available in Nigeria

Lead and cadmium content of different brands and sizes (N=38) of dry cell batteries (zinc-carbon Leclanche systems) available in Nigeria were determined by atomic absorption spectrometry after acid digestion. The average Pb and Cd content of the dry cells are 1077.9±751.7mg/kg (Range 42-3170mg/kg) and 108.3±81.4mg/kg (Range 4.6-410mg/kg) respectively. The mean Pb and Cd contents of dry cells with metal outer cover were significantly lower (p < 0.005) than the corresponding values for dry cells with non-metallic cover. The highest Pb and Cd values were observed in dry cell batteries imported from China. Higher mean Pb and Cd value were observed in dry cells from China (1368.36 vs. 151.47mg/kg), compared to values for dry cells from Indonesia (1032 vs. 84.4mg/kg), Japan (715.2 vs. 131.48mg/kg) and Korea (1137.5 vs. 81.45). Lower Pb and Cd values were obtained in dry cells from Malaysia (709 vs. 12.5mg/kg), Spain (702 vs. 65.8mg/kg), United States (303 vs. 11.1mg/kg) and in the only surviving local brand (408 vs. 34.5mg/kg).Our study revealed that there is an urgent need to introduce an adequate well-established system for collection, separation, storage and management of municipal and industrial wastes containing primary and secondary battery wastes and similar toxic materials to halt the open burning of such wastes within inhabited areas. There is an urgent need to develop in Nigeria an appropriate technology following the principles of waste minimization and sustainable development. Journal of Applied Sciences and Environmental Management Vol. 10 (3) 2006: 37-41

Biomonitoring of Lead, Zinc, and Cadmium in Streams Draining Lead-Mining and Non-Mining Areas, Southeast Missouri, USA

We evaluated exposure of aquatic biota to lead (Pb), zinc (Zn), and cadmium (Cd) in streams draining a Pb-mining district in southeast Missouri. Samples of plant biomass (detritus, periphyton, and filamentous algae), invertebrates (snails, crayfish, and riffle benthos), and two taxa of fish were collected from seven sites closest to mining areas (mining sites), four sites further downstream from mining (downstream sites), and eight reference sites in fall 2001. Samples of plant biomass from mining sites had highest metal concentrations, with means 10- to 60-times greater than those for reference sites. Mean metal concentrations in over 90% of samples of plant biomass from mining sites were significantly greater than those from reference sites. Mean concentrations of Pb, Zn, and Cd in most invertebrate samples from mining sites, and mean Pb concentrations in most fish samples from mining sites, were also significantly greater than those from reference sites. Concentrations of all three metals were lower in samples from downstream sites, but several samples of plant biomass from downstream sites had metal concentrations significantly greater than those from reference sites. Analysis of supplemental samples collected in the fall of 2002, a year of above-average stream discharge, had lower Pb concentrations and higher Cd concentrations than samples collected in 2001, near the end of a multi-year drought. Concentrations of Pb measured in fish and invertebrates collected from mining sites during 2001 and 2002 were similar to those measured at nearby sites in the 1970s, during the early years of mining in the Viburnum Trend. Results of this study demonstrate that long-term Pb mining activity in southeast Missouri has resulted in significantly elevated concentrations of Pb, Cd, and Zn in biota of receiving streams, compared to biota of similar streams without direct influence of mining. Our results also demonstrate that metal exposure in the study area differed significantly among sample types, habitats, and years, and that these factors should be carefully considered in the design of biomonitoring studies.

Uptake of lead and zinc by wild plants growing on contaminated soils

In studies performed in the Aznalcóllar area (Southern Spain), several plant species have been identified as not only being able to grow on these polluted soils, but also to accumulate high amounts of the pollutants in their shoots. A pot experiment was conducted to investigate the phytoextraction efficiency of 11 plant species to extract and accumulate Pb and Zn gradually added to soil, and, therefore, to establish the suitability of these species for remediation of Pb and Zn polluted soils. The experiment was performed with the plants at a concentration of Pb of 500 mg Pb kg −1, and a concentration of Zn of 130 mg Zn kg −1, for 6 weeks of exposure. The mean shoot biomass production was not significantly different from the control for Pb and Zn treatments. It was found that the highest mean concentrations of Pb and Zn were accumulated in shoots of Amaranthus blitoides, Cynodon dactylon, Cichorium intybus and Sylibum marianum. For C. intybus, Pb concentrations in shoots were >1000 mg kg −1, indicating hyperaccumulation for this element. The traslocation of Pb from roots to shoots was minimum in Chenopodium album, indicating significant metal inmobilisation by the roots, and, therefore, this species could be useful in phytostabilization of soils. When the biomass values were taken into account, C. dactylon, Hirsfeldia incana, Malva nicaeensis and Silybum marianum were more effective in removing Pb and/or Zn from the contaminated soil.

Lead and cadmium in human teeth from Jordan by atomic absorption spectrometry: Some factors influencing their concentrations

The aim of this study was to measure the concentrations of lead (Pb) and cadmium (Cd) in human teeth and to investigate the affecting factors. Teeth samples (n=268) were collected from people living in different cities in Jordan including Amman, Zarqa, Al-Mafraq and Irbid and analyzed for Pb and Cd using atomic absorption spectrometry (AAS). A questionnaire was used to gather information on each person, such as age, sex, place where the patient lives, smoking, presence of amalgam fillings inside the mouth, and whether the patient uses toothpaste or not. The mean concentrations of Pb and Cd were 28.91μg/g and 0.44μg/g, respectively. The results indicate that there is a clear relation between Pb and Cd concentrations and the presence of amalgam fillings, smoking, and place of living. Pb was sex-dependent, whereas Cd was not. Our results show that Pb and Cd concentrations in samples obtained from Al-Mafraq and Irbid are higher than those obtained from Amman and Zarqa. Pb was highest in Mafraq, whereas Cd was highest in Irbid. The Pb and Cd concentrations in teeth from smokers (means: Pb=31.89μg/g, Cd=0.49μg/g) were significantly higher than those from nonsmokers (means: Pb=24.07μg/g, Cd=0.37μg/g). Pb and Cd concentrations in teeth of patients with amalgam fillings (means: Pb=31.02μg/g and Cd=0.52μg/g) were significantly higher than those from patients without amalgam fillings (means: Pb=26.87μg/g and Cd=0.41μg/g). Our results show that brushing the teeth daily with toothpaste does not significantly decrease the concentration of both Pb and Cd. The mean concentrations of Pb and Cd do not vary significantly between the ages 20–30, 31–40, and 41–50, but both increased rapidly at age 51–60.

Evaluating the genotoxic effects of workers exposed to lead using micronucleus assay, comet assay and TCR gene mutation test

To evaluate the genotoxic effects of lead (Pb) exposure, 25 workers in a workplace producing storage battery were monitored for three genetic end-points using micronucleus (MN) assay, comet assay and TCR gene mutation test. Twenty-five controls were matched with workers according to age, gender and smoking. The air Pb concentration in the workplace was 1.26 mg/m 3. All subjects were measured for Pb concentration of blood by atom absorption spectrophotometry. The mean Pb concentration of blood in workers (0.32 mg/l) was significantly higher than that in controls (0.02 mg/l). The results of MN test showed that the mean micronuclei rate (MNR) and mean micronucleated cells rate (MCR) in workers were 9.04 ± 1.51‰ and 7.76 ± 1.23‰, respectively, which were significantly higher than those (2.36 ± 0.42‰ and 1.92 ± 0.31‰) in controls ( P < 0.01). It was found in the comet assay that the mean tail length (MTL) of 25 workers and 25 controls were 2.42 ± 0.09 and 1.02 ± 0.08 μm, respectively, there was significant difference between workers and controls for MTL ( P < 0.01), also the difference of the mean tail moment (MTM) between workers (0.85 ± 0.05) and controls (0.30 ± 0.09) was very significant ( P < 0.01). However, in TCR gene mutation assay Mfs- TCR of workers and controls were 1.69 ± 0.15 × 10 −4 and 1.74 ± 0.17 × 10 −4, respectively, there was no significant difference between workers and controls ( P > 0.05). The results of our study indicated that the genetic damage was detectable in 25 workers occupationally exposed to lead.

Phytostabilization of a metal contaminated sandy soil. I: Influence of compost and/or inorganic metal immobilizing soil amendments on phytotoxicity and plant availability of metals

In a lysimeter set-up, compost addition to an industrial contaminated soil slightly reduced phytotoxicity to bean seedlings. The “Phytotoxicity Index” (on a scale from 1 to 4) decreased from 3.5 to 2.8. The same treatment also reduced metal accumulation in grasses: mean Zn, Cd and Pb concentrations decreased respectively from 623 to 135, from 6.2 to 1.3 and from 10.7 to <6 mg kg −1 dry weight. When combined with inorganic metal immobilizing amendments, compost had a beneficial effect on plant responses additional to the inorganic amendments alone. Best results were obtained when using compost (C) + cyclonic ashes (CA) + steel shots (SS). The “Phytotoxicity Index” decreased to 1.7, highest diversity of spontaneously colonizing plants occurred, and metal accumulation in grasses reduced to values for uncontaminated soils. Based on the first year evaluation, C + CA + SS showed to be an efficient treatment for amendment assisted phytostabilization of the contaminated Overpelt soil.

Assessment of lead, cadmium, and zinc contamination of roadside soils, surface films, and vegetables in Kampala City, Uganda

The relationship between traffic density and trace metal concentrations in roadside soils, surface films, and a selected vegetable weed, Amaranthus dubius Mart. Ex Thell., was determined in 11 farming sites along major highways around Kampala City in Uganda. Surface soil, atmospherically deposited surface films on windows, and leaves of Amaranthus dubius were sampled at known distances from the roads and analyzed for lead (Pb), zinc (Zn), and cadmium (Cd) using flame atomic absorption spectrophotometry. Atmospherically deposited trace metal particulates were sampled using window glass as an inert, passive collector. Total trace metal concentrations in soils ranged from 30.0±2.3 to 64.6±11.7 mg/kg Pb, 78.4±18.4 to 265.6±63.2 mg/kg Zn, and 0.8±0.13 to 1.40±0.16 mg/kg Cd. Total trace metal levels in soil decreased rapidly with distance from the road. Total Pb decreased with distance up to 30 m from the road, where it reached a background soil concentration of 28 mg/kg dry weight. The study found background values of 50 and 1.4 mg/kg for Zn and Cd in roadside soils, respectively. Similarly, Pb concentration in Amaranthus dubius leaves decreased with increasing distance from the road edge. The dominant pathway for Pb contamination was from atmospheric deposition, which was consistent with Pb concentrations in surface films. The mean Pb concentrations in leaves of roadside crops were higher than those in their respective roots, with the highest leaf-to-root ratio observed in the Brassica oleraceae acephala group. The lowest Pb and Zn concentrations were found in the fruit compared to the leaves of the same crops. Leaves of roadside vegetables were therefore considered a potential source of heavy metal contamination to farmers and consumers in urban areas. It is recommended that leafy vegetables should be grown 30 m from roads in high-traffic, urban areas.

Lead Stabilization by Phosphate Amendments in Soil Impacted by Paint Residue

The addition of phosphate was evaluated for contaminant stabilization in soils impacted by lead paint residue. Soils sampled from 15 highway bridge sites in Indiana were screened based on residual lead concentrations from paint contamination. Two appropriate bridge sites were identified in Tippecanoe County, Indiana. Soluble phosphate was added to the soil at a mole ratio of 3:1 P:Pb. The efficacy of phosphate treatment was evaluated by a physiologically based extraction test (PBET), uptake of lead by sunflowers, and leaching of lead from soil columns. Sunflowers were established on both field sites, and the mean Pb concentration in the above-ground biomass indicated that the rate of uptake was similar to plants growing in uncontaminated soil. The second bioavailability assessment was the physiologically based extraction test, designed to evaluate heavy metal availability during ingestion. After 1 year at both sites, the addition of phosphate significantly reduced the concentrations of lead extracted by PBET, indicating that the lead in the amended soils had lower bioavailability than in the unamended soils. In the column study, the contaminated soil produced the highest mass of leached Pb, and the addition of P reduced the mass of Pb in the leachate to similar levels found in the uncontaminated soil. Overall, the addition of soluble phosphate to these soils appears to be an effective approach for immobilizing Pb and reducing the associated bioaccessibility.

Analysis of Lead Levels in Local Jordanian and Imported Sheep Meat and Organs Using Atomic Absorption Spectrometry

A total of two hundred and forty random samples were collected equally from mutton, liver and kidney of 40 local (Jordanian) and 40 imported Australian sheep (40 each sub sample). Fresh samples were collected from 12-18 m old sheep slaughtered in abattoirs in Jordan in 2002. Besides, 40 fresh mutton samples of imported Chinese sheep were collected from different markets. Atomic absorption spectrometry (AAS) was used to estimate the lead (Pb) content of the samples. Results indicated that Australian mutton had significantly higher (p < 0.05) mean of lead pollution than that of the local and Chinese muttons. The mean concentration of lead (mg/kg) in Australian, local and Chinese muttons was 4.30, 3.15 and 2.17, respectively. The mean concentration of lead in Australian sheep liver was significantly higher (p < 0.05) than that recorded in the local sheep liver. The mean concentration of Pb in Australian and local sheep liver was 5.69 and 4.52 mg/kg, respectively. The mean concentrations of Pb in the kidney of the Australian and local sheep were not significantly different (p > 0.05). They were 4.59 and 3.87 mg/kg, respectively. On the basis of the samples lead level, 85, 92 and 87.5% of local, Australian and Chinese mutton respectively, exceeded the international safe permissible limit of 1.0 mg/kg. Furthermore, the effect of Pb on animal and human health was discussed.

Characterisation of airborne particulates and associated trace metals deposited on tree bark by ICP-OES, ICP-MS, SEM-EDX and laser ablation ICP-MS

Particulate matter accumulated on tree bark specimens was examined in order to investigate its potential use as a natural monitor to study the impact on local atmospheric conditions. Tree bark from sargent cherry ( Prunus sargentii) and sugar maple ( Acer saccharum Marsh) trees was collected from four locations: Drax (North Yorkshire), Darley Dale (Derbyshire), Galway (Ireland) and Tristan da Cunha. Particulates accumulated on tree bark were prepared for analysis using a microwave-assisted HNO 3 digestion. The bulk elemental content was determined by inductively coupled plasma optical emission spectrometry (ICP-OES) and trace metals were analysed by inductively coupled plasma mass spectrometry (ICP-MS). Analysis of bulk tree bark samples revealed that the highest mean Pb concentration was obtained in Darley Dale samples, 1069 ng g −1, with 147 and 3.2 ng g −1 Pb in Drax and Galway samples, respectively. In Tristan da Cunha samples 0.12 ng g −1 of Pb was detected. Pb, As, Cr, Sb, Sn and Zn were enriched by factors of 10–8650 relative to the background elemental abundance in tree bark obtained from Tristan da Cunha. Particulates accumulated on the tree bark were characterised by SEM-EDX and LA-ICP-MS to provide information on the particle composition and morphology. This study supports the suggestion that the major particulate sources are high-temperature combustion processes. Direct analysis by LA-ICP-MS revealed the potential of this alternative method to investigate the distribution of suspended particulates and their elemental association on the bark specimen.

The assessment of point and diffuse metal pollution of soils from an urban geochemical survey of Sheffield, England

A model of soil variability as a continuous background process with superimposed point contamination was applied to 569 measurements of metal concentrations (Cr, Ni and Pb) in the topsoils of Sheffield, England. Robust estimators of the variogram were shown to be required to describe spatial variation of the metal concentrations at most sampled locations. This is diagnostic of the presence of a contaminant process. Values of the standardized kriging error from the cross-validation of each datum were used to identify spatial outliers for each metal. The ordinary kriged estimates of Cr, Ni and Pb were mapped after removing the outliers to estimate the background variation. Each of the 35 spatial outliers that occured in gardens have concentrations exceeding their Soil Guideline Value for residential land use with plant uptake, highlighting a potentially significant exposure pathway. The frequent observation of coal and furnace waste at these sites suggests that their dispersal, following domestic use and industrial processes, respectively, represents a significant point contaminant process. There was no evidence for spatial clustering of the point process. However, the spatial outliers of Cr and Ni showed a significant association with disturbed sites identified from historical land use maps, in part due to their prevalence in areas of historical steel manufacture. The magnitude of diffuse pollution for each metal in the urban soil was estimated by removing the spatial outliers and comparing robust measures of location with those from a survey of soils developed over the same parent materials in adjacent rural and peri-urban environments. The Winsorized mean Pb concentrations in urban topsoil (203 mg kg−1) were twice the value in the rural environment (101 mg kg−1), highlighting a very substantial diffuse Pb load to urban soils. The equivalent estimated diffuse components in urban soils for Cr and Ni were, respectively, 25% and 14% higher than the rural soils.