Mean Concentrations Of Pb Research Articles

Levels of Cadmium, Lead, Mercury and 137caesium in Caribou (<i>Rangifer tarandus</i>) Tissues from Northern Québec

Levels of cadmium (Cd), lead (Pb) and total mercury (Hg) were assessed in samples of muscle, kidney, and liver from caribou (Rangifer tarandus; n = 317) harvested in two regions of northern Québec between 1994 and 1996. Levels of 137caesium (137Cs) were also examined in muscle samples. Log concentration of the three metals varied significantly among tissues and was lowest in diaphragm muscle and highest in kidneys and liver. Mean Cd (wet weight, w.w.) concentration was 0.01 µg/g in muscle, 7.69 µg/g in kidneys and 1.13 µg/g in liver. Levels of Cd exceeded tolerance thresholds for human consumption in nearly all kidney samples and in nearly half the liver samples. Mean Pb concentration (w.w.) was 0.05 µg/g in muscle, 0.26 µg/g in kidneys and 0.95 µg/g in liver, with few samples exceeding consumption thresholds. Mean total Hg concentration (w.w.) in muscle was 0.03 µg/g, 1.26 µg/g in kidneys and 0.67 µg/g in liver, with concentrations exceeding consumption thresholds in most kidney samples and nearly half the liver samples. Regional differences occurred in log concentration of the three metals for most tissues, with the western region consistently showing higher values. Mean log Cd and Pb concentrations increased with age in kidneys, but log Pb decreased with age in muscle samples. Interactions between month of collection and sex and region also occurred for some metals in some tissues. Mean level of 137Cs in muscle samples was 94.7 Bq/kg, never exceeding the acceptable limit for human consumption.

LEAD DISTRIBUTION THROUGHOUT SOIL, FLORA, AND AN INVERTEBRATE AT A WETLAND SKEET RANGE

Lead pellets from a skeet range impart Pb to the local soil, plants, and animals. Concentrations and distributions of Pb in the various media were studied at the now-abandoned skeet range bordering a cordgrass marsh at the Naval Weapons Station Seal Beach in Southern California. The concentrations of Pb in soil (maximum = 16,200 ppm, dry mass) are significantly correlated to the shot pellet densities. Lead concentrations in plants vary according to species' abilities to inhibit Pb uptake from soil. Horn snails had a mean Pb concentration (1987 ppm, dry mass) over 100 times greater than the leaves of the plant species with the highest mean concentration (18.1 ppm, dry mass) at the same site. Avian predators of gastropods may receive minimum exposure to Pb due to calcium in the shells, but incidental ingestion of soil in addition to direct ingestion of shot pellets may provide significant exposure to birds. Because shotgun pellets may persist in wetland soil for 300 yr, reduction of wildlife exposure to Pb in such cases requires deliberate action.

Blood lead and its effect on Cd, Cu, Zn, Fe and hemoglobin levels of children

The levels of heavy metals, such as Pb, Cd, Cu, Zn and Fe, in whole blood samples of Mumbai and Hyderabad children have been determined. In the present study, 576 blood samples of children (3–6 years old) were collected during 1996–1998 and analyzed for heavy metal contents by anodic stripping voltammetry and atomic absorption spectrometry. The geometric mean concentrations of Pb, Cd, Cu and Zn in blood of Mumbai children were 8.0, 0.10, 86.5 and 398.9 μg dl −1, while those for Hyderabad children were 13.3, 0.13, 100.6 and 483.4 μg dl −1, respectively. The geometric mean concentrations of Fe in the blood of Mumbai and Hyderabad children were 21.9 and 34.5 mg dl −1, respectively. Of the Mumbai children, 61.8% were found to have a blood lead concentration less than 10 μg dl −1, while the corresponding proportion of Hyderabad children was 27.4%. Higher concentrations of Pb in the children's blood were observed at high traffic areas in both cities. A decreasing trend in the hemoglobin content with increasing blood lead levels was observed for Mumbai children. A good negative correlation (−0.61) between the blood lead and iron has been observed for Mumbai children The hemoglobin content of 85% of the study population was found to vary between 8 and 14 g%.

Impact of phase out of leaded gasoline on the air quality in Budapest

As part of an air pollution study in Budapest, size-fractionated aerosol samples were collected by stacked filter units and cascade impactors, and some criteria pollutants and meteorological parameters were recorded in 1996, 1998 and 1999. The samplings were performed at three urban locations including an urban background site, a downtown site, and a tunnel. Elemental composition of the aerosol samples was measured by instrumental neutron activation analysis and/or particle-induced X-ray emission spectrometry; and black carbon (BC) was determined by a light reflectance technique. Since leaded gasoline was completely phased out in Hungary on 1 April 1999, the atmospheric concentrations of some typical transportation-related air pollutants (i.e. Pb, Br, BC and CO) were used for overviewing the actual impact of the phase out on the air quality and on the aerosol characteristics. For the background site, mean concentration of Pb and Br was not changed significantly. In the downtown site, the phase out resulted in a concentration decrease by a factor of 3–4 for Pb and Br. For the tunnel, concentrations of Pb and Br were decreased by a factor up to 9 and 28, respectively. Correlation between the pollutants, their crustal enrichment factors, and average elemental mass size distributions are also presented and discussed.

Multi-element analysis of road-deposited sediment in an urban drainage basin, Honolulu, Hawaii

Road-deposited sediment (RDS) and its associated contaminant load play a critical role in degrading receiving water bodies. Few quantitative multi-element RDS studies exist, and there are none from Hawaii. This lack of baseline data combined with concerns with high concentrations of Pb and Cu in fish and enrichment of Cu, Pb and Zn in bed sediments from Manoa Stream, Hawaii, lead to a detailed characterization of RDSs in Manoa basin. Data for a total analysis of 23 elements using inductively coupled plasma atomic-emission spectrometry and instrumental neutron activation analysis and 16 elements using a 0.5 M HCl partial leach are presented for RDSs and background soils. Concentration data, comparisons with environmental guidelines, and concentration enrichment ratios (CERs) all indicate that RDS in Manoa has a significant degree of anthropogenic pollution. The most environmentally important elements were Pb, Sb and Zn. Concentrations of these elements, primarily vehicle contributed, compare favorably with those from other studies of RDS. The high mean concentration of Pb (151 mg/kg) compared to background soils (13 mg/kg) indicates remobilization of Pb previously stored in soils and transported to road surfaces by water erosion processes. The higher Pb CERTotal in RDSs compared to bed sediments from Manoa Stream suggests a potential link via ubiquitous storm drains and subsequent dilution with less contaminated fluvial sediments. Data from the HCl leach also support Pb and Zn as having significant anthropogenic signals, and Cu having a moderate signal. These data indicate that RDSs in Manoa basin are generally contaminated with certain potentially toxic elements and the legacy of past use of leaded gasoline is still a concern in this urban drainage system.

Heavy metal trends in floodplain sediments and valley fill, River Lahn, Germany

Sampling along the River Lahn, a major tributary to the River Rhine that flows through an agrarian region of west-central Germany, reveals that heavy metal pollution occurs outside major industrial regions and mined landscapes. Along a 60-km reach of the river between Marburg and Wetzlar, mean concentrations of Cu, Pb and Zn at depths of 5 and 15 cm in four floodplain transects were greater than background levels. Concentrations declined sharply between 15 and 25 cm. Laterally, concentrations peaked at the bank top and in the near-channel zone of the floodplain. Beyond the near-channel zone (generally up to 100 m from the channel) concentrations were much less and fairly uniform to the valley wall. The clustering of metals close to the channel suggests that they are a fluvial rather than an eolian deposit. During floods of a moderate magnitude, sediments and attached metals are deposited soon after the river overtops its banks. Although the overall store of metals in the valley is less than that along the Rhine, near-channel metal concentrations are similar to those along rivers draining major industrial and mined areas.

Accumulation of heavy metals in food plants and grasshoppers from the Taigetos Mountains, Greece

Geogenic, as well as anthropogenic heavy metals from distant sources, gradually increase the level of toxic metals in natural environments and these will be increasingly taken up by the plants and transferred further up the food chain. The level of different heavy metals (Hg, Cd, Pb) was studied in the producers (food plants) and consumers [four species of acridid grasshoppers: Calliptamus italicus (L.), Oedipoda caerulesens (L.), O. germanica (Latr.) and Chorthippus( Glyptobothrus) crassiceps(Ramme, 1926)] of a grassland located 1200 m above the sea level in the Taigetos Mountains, Peloponnesus, Greece. The concentrations of heavy metals in the food plants and grasshoppers were in the order Pb > Cd > Hg and the mean concentration of Pb was about 55 and 20 times the concentrations of Hg and Cd, respectively. The solely herbivorous C.( G.) crassiceps had a significantly higher Hg-concentration than in the food plants, but it did not exceed that of Cd and Pb. Cd-concentration in the grasshoppers was significantly higher than in food plants, and female grasshoppers had higher Cd accumulation than males. Lead accumulation in grasshoppers was always lower than in their food plants. The accumulation factors of these elements in the grasshoppers were found in the order Cd > Hg > Pb, thus showing greater affinity to Cd accumulation. Significantly higher concentration of Hg in both sexes of C.( G.) crassiceps than in other three grasshoppers proved this species to be a comparatively better bioindicator of Hg pollution. Elevated concentrations of Cd in both, females and males of all four grasshopper species suggested that any grasshopper, irrespective of the sex, could equally play the role of bioindicator. Studies on the bioaccumulation and biotransfer of different heavy metals showed that the organisms of such distantly located ecosystems were also exposed to measurable amounts of toxic heavy metals.

Cathodoluminescence in Calcite Cements: New Insights on Pb and Zn Sensitizing, Mn Activation, and Fe Quenching at Low Trace-Element Concentrations

ABSTRACT The role of Pb and Zn as sensitizers of cathodolumines (CL) in sedimentary carbonates is still speculative, as is the relationship between Mn, Fe, and CL intensity at low concentrations of Mn and Fe. We address these questions using calcite cements from the Lower Oligocene Suwannee Formation of Florida, which have mean Mn, Pb, Zn, and Fe concentrations less than 45 ppm. Only a small fraction of these cements exhibit visible CL, but when present, the luminescence is orange to reddish orange. Trace-element contents were measured using a synchrotron x-ray fluorescence microprobe, and CL intensity was approximated by spot-metered photomicrograph exposure times. Based on Mn and Fe contents, four cement populations can be defined. Group I is luminescent calcite with Mn > 25 ppm and molar Mn/Fe > 1.8. Group II contains both luminescent and nonluminescent cements, all with Mn > 25 ppm, molar Mn/Fe 25 ppm, molar Mn/Fe 100 ppm. Group IV is nonluminescent calcite with Mn < 25 ppm and variable Fe. These groupings and statistical analyses of the data (Mann-Whitney tests and factor analyses) confirm that 25 ppm Mn is necessary to initiate visible CL, and that Mn is the sole control on CL intensity when Mn and Fe contents are very low (<100 ppm). The data also establish 100 ppm Fe as a new minimum for the quenching of CL when Mn is below 200 ppm. There is no evidence in our data that Pb or Zn concentrations in tens of parts per million either activate or sensitize CL. The Mann-Whitney test shows that there is no statistical evidence at the 95% confidence level to indicate that luminescent and nonluminescent cements reflect different populations of Pb and Zn, except for Group II cements that have more Pb in nonluminescent cements than in otherwise chemically equivalent luminescent cements. Factor analysis shows that CL intensity in all luminescent cements is unrelated to Pb or Zn concentrations. Given that Pb or Zn sensitizing is lacking in low-Mn calcites like the Suwannee cements, it is hard to imagine how these elements could play a significant role in calcites containing even more Mn, as is typical of most sedimentary carbonates.

Elevated lead exposure in American woodcock (Scolopax minor) in Eastern Canada.

We investigated the degree and incidence of elevated lead (Pb) accumulation in the American woodcock (Scolopax minor) in eastern Canada by measuring the concentration of Pb in undamaged wing bones of 1,588 birds from Ontario, Quebec, Nova Scotia, and New Brunswick. Overall median bone-Pb concentrations were 21 microgram/g (DW) for adults and 11 microgram/g for young of the year. A high proportion of birds had elevated Pb concentrations, compared with other wild bird species. Fifty-two percent of adults and 29% of young of the year had bone concentrations exceeding 20 microgram/g. Pb concentration varied significantly with age, gender, and geographical region (p </= 0.0001). Mean Pb concentrations were lower for young of the year than for adults and lower for males than for females in both age groups. Atlantic Canada (New Brunswick and Nova Scotia) tended to have the highest frequency of individuals with elevated Pb accumulation. Potential sources of Pb exposure in woodcock include ingestion of spent lead shot from hunting, ingestion of Pb-contaminated soil, and/or ingestion of Pb-contaminated earthworms.

Daily intake of heavy metals by infants through milk and milk products

Concentrations of the essential elements Zn and Cu and potentially toxic elements Pb and Cd in different milk samples and baby food materials were measured, primarily to assess whether the intakes comply with recommended desired levels for essential and permissible levels for toxic elements. The geometric mean concentrations of Pb, Cd, Cu and Zn in different types of milk were found to vary from 1.70 to 3.35, 0.07 to 0.10, 43.2 to 195 and 1772 to 4230 μg/l, while the same in different baby foods had values from 39.5 to 77.7, 0.45 to 17.7, 1106.3 to 3157.3 and 9367 to 34 592 μg/kg, respectively. The concentration of Cd was found to be very low (0.1 μg/l) and fairly constant in all types of milk. The lead content in cow milk was observed to be the lowest even in comparison with breast milk. Concentrations of all these metals are approximately one order of magnitude higher in baby food products than those observed in different types of milk owing to higher fat content. The infant baby food Amul Spray contains low concentrations of toxic (Pb and Cd) and high concentrations of essential (Cu and Zn) elements. The daily intakes of Pb, Cd, Cu and Zn by infants through milk and baby foods marketed in Mumbai city have also been estimated. The daily intakes of Pb (1.1 μg/kg) and Cd (0.01 μg/kg) for infants through baby foods are well below the recommended tolerable levels of 3.57 μg/kg and 0.8–1.0 μg/kg, respectively. Similarly the daily intake levels of essential elements are also significantly lower than the recommended desirable levels of 3–5 mg and 0.5–1.0 mg for Zn and Cu, respectively. Milk from an Indian mother also does not provide adequate levels of essential elements to the infants and children.

Expression of lymphocyte subpopulations, cytokine serum levels, and blood and urinary trace elements in asymptomatic atopic men exposed to an urban environment.

The objective of this study was to analyze the role of some trace metals in the immune system of nonallergic or atopic men. One of these elements (Zn) is essential for immune function, whereas others, present in the urban environment, are known to be allergenic (Ni and Cr) or toxic (Pb). Serum levels of interleukin (IL) 2, 4, 5, and 13 and of interferon-y and immunoglobulins, blood lymphocyte subsets, blood concentrations of Pb and Zn, serum levels of Zn, and urinary Cr and Ni concentrations were determined in 17 nonallergic men (mean age 34 years) and 17 healthy nonsymptomatic atopic men living in urban areas. The mean blood concentration of Pb (a marker of exposure to toxic agents) was 11 microg/dl in both groups, which showed similar levels of blood Zn and of urinary Ni and Cr, whereas the serum Zn concentration was lower in the atopic group. Serum IgE levels were much higher in atopic men than in nonallergics, whereas serum IL-2, IL-5, and IL-13 concentrations were lower, possibly due to binding to tissue receptors and cells. Moreover, in atopic subjects, numbers of blood CD4+-CD45RO-"virgin" lymphocytes were significantly lower and the CD4+ -CD45RO+/CD4+ -CD45RO- ratio was more elevated, indicating an activation of the immune system. Serum IgE levels of atopic men, in contrast to those of nonallergic subjects, were correlated with CD19+ and CD5--CD19+ B lymphocytes. Blood Pb levels of both groups of men were correlated with CD4+, CD4+-CD45RO+, and HLA-DR+ [activated T-, B-, CO4+ -C. and natural killer (NK) cells] lymphocytes; in particular, blood Pb levels of the nonallergic men were also significantly correlated with CD25+ cells activated by IL-2, whereas those of the atopic men were also correlated with CD3--HLA-DR+ (B- and NK-cells) and CD5--CD19+ lymphocytes. Besides serum Zn levels, urinary Ni and Cr of nonallergic men were correlated with several immune parameters; in particular, urinary Cr was correlated with serum IL-5 and IgE and urinary Ni was correlated with CD4+ -CD45RO+ and CD3+ -CD25+ lymphocytes. This correlation of Ni and Cr, also found in previous studies in nonallergic subjects, confirms the hypothesis that these metals are involved in mechanisms of immune response regulation and that allergy to Ni or Cr represents an alteration of physiological mechanisms. Previous experimental studies have demonstrated that Pb exerts immunomodulatory effects on CD4+ and B- lymphocytes, enhancing the production of Th2-like cytokines and IgE. These experimental results confirm those of this study, showing in atopic men the correlation of B-lymphocytes with both blood Pb and serum IgE levels. This suggests that Pb may enhance the incidence of atopy in populations exposed to an urban environment.

Heavy Metal Concentrations in and Around Households Near a Secondary Lead Smelter

Housedusts and garden soils were sampled in 14 houses in the vicinity of a secondary Pb smelter and analysed for concentrations of Pb, Zn, Cu, Cd, As, and Hg. Sixty-one topsoil samples were also taken from a 2 km2 grid covering the smelter grounds and surrounding residential areas and analysed for concentrations of Pb, Zn, Cd and Cu. Contour maps generated from the grid data indicate significant contamination in the area (maximum Pb concentration 58 500 μg g-1), particularly down-wind of the smelter grounds. A geometric mean Pb concentration of 2225 μg g-1 was recorded in garden soil and similarly elevated levels were recorded for Zn, Cd, As and Sb. In housedusts, a geometric mean Pb concentration of 1668 μg g-1 was observed. Whilst housedust metal concentrations were generally elevated, compared to other urban or residential areas, there appears to be a large degree of attenuation of the metals between the exterior and interior environments of the homes studied. A significant correlation was not recorded between metal concentrations of garden soils and housedusts. There were significant correlations for: distance from the smelter against garden soil metal concentrations; garden soil metal concentrations against each other; housedust metal concentrations against each other; and house age against garden soil metal concentrations.

Using a triad approach in the assessment of hazardous waste site leaching from a superfund site to an adjacent stream

AbstractA triad approach was used in the evaluation of sediment in the Wolf River adjacent to the North Hollywood Dump, a federally listed superfund site. Chemical analyses were done for 18 organochlorine pesticides, 21 polychlorinated biphenyl (PCB) congeners, and 10 metals. Sediment toxicity was evaluated with freshwater invertebrates, Chironomus tentans and Hyalella azteca. Benthic macroinvertebrate diversity and abundance were assessed with a family‐level biotic index. Mean Al, Ba, Cd, Cu, Fe, Ni, Pb, and Zn concentrations were significantly higher in sediments collected in the spring. Both spring and fall sediments exhibited toxicity downstream from, adjacent to, and upstream from the dump, with toxicity significantly higher in fall sediments; however, a consistent trend was not observed. Toxicity was typically greater in the fall, and metal concentrations were typically higher in spring sediments, suggesting that metals were not responsible for the toxicity. Sediment‐associated organochlorine pesticide and PCB congener concentrations were all below detectable limits, suggesting that these potential contaminants are not contributing to the observed toxicity. No differences were found in benthic macroinvertebrate community structure, which was composed of predominantly pollution‐tolerant families, among seasons or river reaches, which appear to be limited by the physical characteristics of the river (e.g., substrate instability, low total organic carbon (&lt;0.6%), and water velocity). Sediments in urban reaches of the Wolf River appear to be degraded; the North Hollywood Dump cannot be isolated as a source of toxicity in this study. In situ testing, sediment toxicity identification and evaluation testing, acid‐volatile sulfide analyses, or artificial substrate work would be appropriate to follow.

The role of sediment ingestion in exposing wood ducks to lead

Waterfowl on lateral lakes of the Coeur d'Alene River and on Lake Coeur d'Alene have been poisoned for many years by lead (Pb) from mining and smelting. In 1992 we undertook a study in the area to determine the importance of sediment ingestion in exposing wood ducks (Aix sponsa) to Pb. Digesta were removed from the intestines of wood ducks collected from contaminated and reference areas. The mean Pb concentration in the digesta of wood ducks from the contaminated area was 32 p.p.m. dry weight. The sediment content was estimated to average less than 2% of the dry weight of the wood duck diet. The lead concentrations in the digesta were closely correlated with the concentrations of acid- insoluble ash, Al, Ti and Fe in the digesta and these four variables are associated with sediment. Samples containing low concentrations of these variables also had low concentrations of Pb. These results suggest that most of the Pb in the digesta came from ingested sediment, rather than from plant material in the diet. The importance of ingested sediment as a source of lead was unexpected, because wood ducks are surface feeders on aquatic plants and they rarely dabble beneath the surface or feed on the bottom. However, it appears that sediment ingestion is sometimes the principal route of exposure to environmental contaminants that are not readily taken up by plants and invertebrates and this route should be considered in risk assessments of waterfowl

Determination of the extent of anthropogenic Pb migration through fractured sandstone using Pb isotope tracing

The extent of vertical migration of anthropogenic Pb beneath a medieval smelting site in Derbyshire, U.K. has been estimated using the determination of total Pb concentrations and 206Pb/ 207Pb isotope ratio from samples taken down 6 m of drill core. Preliminary studies of total Pb concentrations established that the surface slag derived from the smelting contained up to 16% Pb and that the normal background levels in uncontaminated sandstone were 10±2 ppm. Sample analyses beneath the site revealed elevated Pb concentrations in fracture infill clays (270 ppm Pb) and sandstone (76–83 ppm Pb). Both are well above the background Pb concentration. Lead isotope analysis of the slag wastes, the underlying contaminated sandstone and fracture infill has shown that all 3 contain very similar isotope ratios for 206Pb/ 207Pb (1.1802–1.1820). However, matched control sandstone samples show that the background 206Pb/ 207Pb isotope ratio (1.1670 ± 0.003) is distinctly different. This would indicate that both the sandstone and fracture infill underlying the historical smelting site contain a substantial proportion of Pb that has been derived from the overlying contamination. The application of total Pb concentrations along the core and isotope analysis suggest that anthropogenically derived Pb from the smelting site (that was operated between 665 and 445 a BP) has migrated to a depth of 4.50 m. Assuming a uniform migration rate and a mean time of migration of 555 a, then the mean migration rate is estimated to be 8 ± 2 mm/a. The proportion of natural versus anthropogenic Pb in the samples has been estimated from small variations in the 206Pb/ 207Pb isotope ratio. If the slag is considered to contain 100% anthropogenic Pb and the uncontaminated sandstone considered to contain 100% natural Pb, the linear interpolation can be applied between the 2 end members of the isotope ratio. The use of this approach to the 206Pb/ 207Pb ratio measurements has shown that 88% of the Pb in the contaminated sandstone (i.e. 69 ppm from a mean total Pb concentration of 78.5 ppm) has been derived from the anthropogenic Pb at the surface. For the fracture infill sample taken at a depth of 4.50 m, and with a total Pb concentration of 270 ppm, the % of Pb that has been derived from the slag wastes is approximately 98% (equivalent to 265 ppm Pb). The remaining Pb in both these samples (9.4 and 5 ppm, respectively) is deduced to have originated from the natural background concentration of Pb in the sandstone. The closeness of these estimates to the measured background concentration, suggests that a simple two-source model of Pb contamination is valid for this site.

Heavy Metal Pollution in Children Playgrounds in Hong Kong and Its Health Implications

Due to the scarcity of land in Hong Kong, most of the children playgrounds are being built on marginal lands which may be subjected to serious atmospheric emission. Hence, children playing in these playgrounds are exposed to a potential health risk. The aim of this study was to evaluate heavy metal pollution in children playgrounds using surface dusts and soils as indicators. Surface dust and soil samples were collected from seven selected playgrounds with different levels of traffic volume and urban development for the determination of total Cd, Cu, Pb and Zn concentrations. The mean Cd, Cu, Pb and Zn concentrations of surface dusts were 2.63, 201, 302 and 1517 mg kg−1 respectively, whereas for soils they were 2.30, 28.4, 195 and 237 mg kg−1. The results indicated elevated concentrations of Cd, Cu, Pb and Zn in both dust and soil samples especially for those samples collected from busy commercial and industrial areas i.e., Mei Foo, Tsim Sha Tsui and North Point. Surface dusts were enriched relative to soils in each metal, on average, by factors ranging from 1.1 to 7.1. The metal contents in dust and soil samples were significantly correlated with traffic volume. Significant correlations were also noted among all the metals studied indicating that Pb and Zn in the samples may be due to the same source i.e., automobile. The soil Pb and Zn contents of Mei Foo and North Point were higher than the investigation level of the Dutch Criteria for these two metals which indicated that further investigation is required to confirm their health hazard on children playing in these playgrounds.

ATMOSPHERIC LEAD POLLUTION FROM VEHICULAR EMISSIONS – MEASUREMENTS IN PLANTS, SOIL AND MILK SAMPLES

The changing levels of lead (Pb) in the soil and vegetationalong two National Highways near Lucknow, India, wereinvestigated. The pattern of Pb deposition, as reflected bysoil Pb burdens, showed decrease in concentration withincreasing distances from the road margins. At both the sitesPb concentration was above background concentration even atthe soil core depth of 15 cm. Oryza sativa, Colocasiaesculentum, Luffa cylindrica and Cynodon dactylonplants contained a high mean concentration of Pb over theirrespective controls, with more accumulation in the undergroundportions of the plants. Milk samples, collected from cattlethat normally graze on the roadside pasture-lands dominatedby Cynodon dactylon, contained Pb at an elevatedconcentration.

The analysis of trace elements in human teeth collected from the Oxfordshire area in the UK

The concentrations of trace elements in the dental enamel from human teeth collected from the Oxfordshire area of the UK have been measured using PIXE. Trace elements heavier than Ca were analyzed and correlated to a number of parameters including the health of the teeth and the age and gender of the donor. The concentration of Fe, Sr and Cu were found to correlate with dental health, and the mean concentration of Pb was found to be 7 μgg −1 for under 25 year olds and increased with age. The uniformity of the trace elements, and its effect on the statistical distribution of their concentrations is discussed.

Heavy Metal Contents in Vegetables and Market Garden Soils in Hong Kong

Urbanization is one of the major causes of soil pollution of many market garden soils in various municipalities. The aim of this project was to monitor the heavy metal contents in market garden soils and vegetables in Hong Kong as affected by human activities. Cadmium, Zn, Cu and Pb concentrations were determined on soil and two vegetable samples, Brassica chinensis and B. parachinensis, collected from eleven different locations. The EDTA-extractable heavy metal concentrations in soil were analysed to assess their availability for plant uptake. Mean total Cd, Cu, Pb and Zn concentrations for all soil samples were (mg kg−1): 1.01 (range 0.25 to 2.17), 18 (range 5 to 67), 60 (range 24 to 113) and 105 (range 20 to 232), respectively, and were all below the investigation levels for contaminated soil. The heavy metal concentrations of soils in more urbanized sites were consistently higher than some remote sites. Significant positive correlations were found between EDTA-extractable and total metal contents in s...

Blood lead and cadmium determination: Results of the Italian external quality assessment scheme

The procedures adopted in the Italian external quality assessment scheme (EQAS) for blood Pb (B-Pb) and Cd (B-Cd) determination, including the preparation of control materials, are described. Each scheme involves the use of internal quality control materials and the participation in periodical external quality assessment trials. All control materials are prepared at the Laboratory of Clinical Biochemistry, Italian National Institute of Health (Istituto Superiore di Sanita, ISS), as the reference centre. Computerized procedures have been adopted whenever possible, i.e. sample randomization, data transfer and treatment. The analytical performance of the participating laboratories, evaluated from the results obtained in ten years of activity, is reported. A total of eight phases has been carried out between 1983 and 1993. Over the course of these ten years, a positive trend was observed for B-Pb towards a smaller bias and a lower percentage of laboratories with poor performance. In the eighth phase, taking into account the results from all participants, the mean absolute inaccuracy for B-Pb was 32 μg/l (mean Pb concentration in control samples, 165 μg/l). The percentage of laboratories providing results within established acceptability limits for at least 80% of the examined samples (good performers) increased with time from 28% in the first phase to 48% in the last phase. The laboratories providing less than 50% of acceptable results (poor performers) decreased from 35% in the first phase to 22% in the last phase. As regards B-Cd, mean absolute inaccuracy decreased from 0.96 μg/l to 0.55 μg/l between the first phase and the sixth phase. The percentage of good performers increased from 45% to 62% and that of poor performers decreased from 31% to 5%. From the seventh phase a large group of new laboratories agreed to participate in the EQAS for B-Cd and the inaccuracy rose to 0.75 μg/l (mean concentration: 2.7 μg/l) and the percentage of poor performers rose to 24%, whereas the percentage of good performers remained almost unchanged.