Soil Lead Levels Research Articles

Lead exposure assessment from study near a lead-acid battery factory in China

The production of lead-acid battery in China covered about one-third of the world total output and there are more than 2000 lead-acid battery factories. They may cause the major environment lead pollution. Blood lead levels of several hundreds of residents were over 100μg/L due to the waste discharges from a lead-acid battery factory in Heyuan, Guangdong province. This study aimed to find out the environmental lead sources, the human lead exposure pathways, and the amplitudes from a lead-acid battery factory. The study results showed that lead levels in soil, dust, tree leaves and human blood declined with the distances increased from the production site. Twenty nine of 32 participants had blood lead levels of over 100μg/L with an exceptional high value of 639μg/L for one child. This result suggested that the lead-acid battery production from this factory has caused the elevated lead levels in its neighboring environment and residents. Dust intake was the dominant exposure pathway for humans (over 90%). The lead levels found in adult and toddler (6.19 and 50.1μg/kg/d, respectively) in the polluted area were far higher than the provisional tolerable weekly intake (PTWI) of 25μg/kg body weight (translated into 3.5μg/kg/d), which was established by the joint FAO/WHO Expert Committee. Blood lead levels within the family members were strongly correlated with the house dust lead levels. Our results in this study suggested that further studies in this area should be performed to assess human exposure and relevant human health risks from living close to lead-acid battery factories.

Environmental Lead: Rabito et al. Respond

We thank Mielke for his interest in our study of residential lead hazards in New Orleans (Rabito et al. 2012). In our study we found that most homes had either dust or soil lead above federal standards and concluded that children are at risk for lead exposure. Regarding the specific issue of whether soil lead has increased or decreased, we agree that a direct comparison between census-level soil lead survey data and direct measure-ments of residential samples has limitations. To reiterate the limitations outlined in our article (Rabito et al. 2012), differences in the number of soil samples, the sampling methodology, and the sample location limited our ability to directly measure any change in soil lead levels. Although it is of interest to know whether soil lead has increased or decreased as a result of Hurricane Katrina, our focus was to measure current residential lead hazards, because lead contamination in and around homes is the primary pathway of exposure for children (Lanphear and Roghmann 1997). Our finding that 61% of homes had lead levels above federal standards provides evidence that New Orleans children are at high risk of exposure. That the samples were collected from homes typically considered to be low risk (given the socio-demographic characteristics of the sample) is cause for added concern. In his letter, Mielke refers to trends in blood lead levels. The issue of whether blood lead levels are increasing or decreasing in New Orleans children—which was not within the scope of our study (Rabito et al. 2012)—is not easily addressed using surveillance data. Screening practices and rates drive the reported prevalence in any given year. Zahran et al. (2010) compared aggregate blood lead levels derived from the Louisiana Childhood Blood Lead Surveillance System (CBLSS) pre-Hurricane Katrina to levels post-Hurricane Katrina and found that median blood lead had decreased. However, profound changes in the socio-demographic makeup of the New Orleans population make the comparison vulnerable to significant bias (Bloomberg 2011). The surveillance data provided by Mielke supports our notion that the post-Hurricane Katrina population screened under the CBLSS is not stable from year to year. As stated by Mielke, 6.4% of children had elevated blood lead levels in 2008, but the estimate decreased to 3.3% in 2010. This decrease might not be valid because the majority of children in the 2008 cohort were from the inner city (with the highest prevalence of old housing) whereas the 2010 cohort included a higher proportion from outer areas of the city (considered low risk based on housing age). The assumption by Zahran et al. (2010) that soil lead serves as a proxy for length of lead exposure is likely not valid given the amount of housing destabilization and subsequent mobility of the population in the years following the storm. Finally, low screening rates, coupled with a reporting level of > 10 µg/dL (widely accepted as above the level of concern) does not allow for the valid estimation of the preva-lence of elevated blood lead levels in New Orleans children. Regardless of the inconclusive nature of blood lead data, given that 61% of sampled homes have significant lead hazards, we maintain that New Orleans children who live in old housing are at risk for lead exposure independent of race or income. We support the recent statement by the Centers for Disease Control and Prevention Advisory Committee on Childhood Lead Poisoning Prevention that “the goal of primary prevention is to ensure that all homes become lead-safe and do not contribute to childhood lead exposure” (Centers for Disease Control and Prevention 2012). The City of New Orleans has made strides in its fight to reduce lead hazards in public places; however, they should not relax in their efforts to protect the environ-ment from further contamination.

Single-Step Extraction to Determine Soluble Lead Levels in Soil

This study investigated single-step extraction using EDTA to extract the amount of potentially soluble Pb in soil, which would be almost as much as that in the first four Pb fractions of Tessier's sequential extraction procedure (SEP), with or without the immobilization amendment hydroxyapatite under different extraction conditions such as concentration and extractant pH. The results clearly showed that 0.1M EDTA (pH 7.5) with a soil/extractant ratio of 1:100 can extract almost 90% of the first four Pb fractions of SEP, and EDTA-extracted Pb was positively correlated with the first four Pb fractions even in Pb-immobilized soil. In conclusion, single-step extraction using EDTA was found to be a useful method to evaluate potentially soluble Pb even in Pb-immobilized soils.

Remediating Soil Lead with Fish Bones

Remediating Soil Lead with Fish Bones

Environmental Lead after Hurricane Katrina: Implications for Future Populations

Background: As a result of Hurricane Katrina, > 100,000 homes were destroyed or damaged and a significant amount of sediment was deposited throughout the city of New Orleans, Louisiana. Researchers have identified the potential for increased lead hazards from environmental lead contamination of soils.Objectives: We assessed the distribution of residential soil and dust lead 2 years poststorm and compared soil lead before and after the storm.Methods: We conducted a cross-sectional study in New Orleans in which households were selected by stratified random sampling. A standard residential questionnaire was administered, and lead testing was performed for both the interior and exterior of homes. Logistic regression was used to identify significant predictors of interior and exterior lead levels in excess of allowable levels.Results: One hundred nine households were enrolled; 61% had at least one lead measurement above federal standards. Of homes with bare soil, 47% had elevated lead and 27% had levels exceeding 1,200 ppm. Housing age was associated with soil lead, and housing age and soil lead were associated with interior lead. Race, income, and ownership status were not significantly associated with either interior or exterior lead levels. The median soil lead level of 560 ppm was significantly higher than the median level of samples collected before Hurricane Katrina.Conclusions: The high prevalence (61%) of lead above recommended levels in soil and dust samples in and around residences raises concern about potential health risks to the New Orleans population, most notably children. Steps should be taken to mitigate the risk of exposure to lead-contaminated soil and dust. Further research is needed to quantify the possible contribution of reconstruction activities to environmental lead levels.

Testing and educating on urban soil lead: A case of Chicago community gardens

Chicago has many urban agricultural projects that provide a source of local food for city dwellers. Urban garden soil, however, may contain lead pollution, and soil quality can vary dramatically from location to location. Soil testing and access to information should improve gardeners’ abilities to grow food safely in urban soils, and to know if time-consuming or expensive measures to avoid lead exposure or enrich the soil are really necessary for their gardens. Soil quality including lead levels was profiled in 10 Chicago gardens. Gardens growing food within raised beds were compared to gardens growing food without raised beds. We also quantified lead in adjacent areas of bare soil or where children might play. Soil lead was measured in two ways: through acid digestion with the Environmental Protection Agency (EPA) 3050B method and a Mehlich-III extraction. The overall mean soil lead level reported through the EPA method was 135 parts per million (n=86), with a range from 10 parts per million to 889 parts per million in individual soil samples. The average for the Mehlich-III method was 63 parts per million. Lead levels in most gardens were not a concern, although gardens contained excessive fertility. Use of raised beds reduced lead levels and thus the potential risk of lead ingestion from plant uptake, but further study comparing the use of raised beds with a greater number of gardens is required. Higher lead levels in soil from nearby areas suggest the possibility of contamination to raised beds and supports the notion that areas with bare soil adjacent to gardens may be an equal or greater source of risk. Our results suggest that the Mehlich-III soil test was positively correlated with the more costly EPA test and could be developed as less expensive test easily conducted by commer­cial soil-testing labs. Additionally, a training pro­gram about urban garden safety with live and online options was created and evaluated with questionnaires given to Master Gardeners. Both live-trained and online-trained groups’ quiz scores improved significantly after the trainings, demonstrating that education about urban soil management can be effective.

Effect of Chromium and Lead on Yield, Chemical Composition of Essential Oil, and Accumulation of Heavy Metals of Mint Species

A pot culture experiment was conducted to investigate the effect of increasing levels (30.0 and 60.0 mg kg−1 soil) of chromium and lead on the yield, chemical composition of essential oil, and phytoaccumulation of heavy metals of three mint species (Mentha arvensis, M. piperita, and M. citrata). The fresh herbage yield of M. arvensis was not significantly affected by the application of chromium and lead, but its essential oil yield was significantly decreased by the application of chromium and lead as compared to the control. The fresh herbage, root yield, and essential oil yield of M. piperita were significantly increased and those of M. citrata were decreased by the increase in the levels of chromium and lead applications. The levels of α-pinene, β-pinene, sabinene, β-myrcene, limonene, menthone, and isomenthone in M. arvensis and M. piperita oil and of sabinene, pinene, and linalyl acetate in M. citrata oil were considerably affected by the application of chromium and lead to soils as compared to control plants. The concentrations of chromium in shoots and roots of mint species significantly increased as the levels of chromium in soil increased. The increases in the levels of lead in soil enhanced the concentrations of lead in the shoots and roots of mint species as compared to the control. The accumulations of chromium and lead were greater in the roots than in the shoots in all the three species of mint. Mentha piperita was found to be the most suitable crop for cultivation in the chromium- and lead-contaminated soils, followed by M. arvensis and M. citrata.

LEAD: From Devastation Comes Hope

Even as the Gulf Coast grapples with possibly its worst environmental catastrophe ever, a silver lining has emerged from the devastation of the stormy summer of 2005: both soil lead levels and children’s blood lead levels fell dramatically across New Orleans, Louisiana, after Hurricanes Katrina and Rita swept in clean sediment over the city’s lead-contaminated soil.1 This positive outcome bolsters the case for soil remediation as a way to protect children from lead poisoning. Howard Mielke, a research professor at the Tulane/Xavier Center for Bioenvironmental Research, says he and his colleagues “took advantage of a catastrophic natural event to examine changes in the environment and health.” Along with Sammy Zahran at Colorado State University and colleagues, Mielke measured soil lead levels at 46 New Orleans sites in 2000 and in 2006. The researchers obtained pre- and post-hurricane blood lead data for 13,306 children aged 6 years and younger from the Louisiana Childhood Lead Poisoning Prevention Program. After the hurricanes, only 6 of the 46 sites had soil lead concentrations above 400 mg/kg, compared with 15 of 46 sites before the hurricanes. The 400 mg/kg (ppm) cutoff is the point at which the U.S. Environmental Protection Agency recommends remediation of bare soil in children’s play areas; a cutoff of 1,200 ppm is recommended for other bare soil areas. Median soil lead levels fell 46% (from 328.54 mg/kg to 203.33 mg/kg), and median blood lead declined 33% (from 5.14 μg/dL to 3.45 μg/dL). In neighborhoods where soil lead declined by 50% or more, blood lead dropped by 53% on average. Children born after Katrina and Rita had the lowest blood lead levels of all those studied.1 “There’s a tremendous amount of lead in New Orleans’ soil—and all cities,” says Mielke. This toxic reservoir, which accumulated when lead was added to paint and gasoline, is constantly being redistributed by rain, wind, and construction activity. The hurricanes’ blanket of cleaner soil—sediment from Lake Pontchartrain and nearby wetlands that was carried through the city’s breached levees by the storm surge—likely will not persist, predicts Mielke. However, the natural effect of the blanket of sediment is duplicated by soil remediation, in which clean soil with no more than 5 ppm lead is hauled in and deposited on a geotextile barrier. The barrier allows water to pass through but contains the lead and prevents anyone from digging into contaminated soil underneath. Soil is often an underappreciated source of childhood lead exposure in cities, relative to lead paint in homes,2 yet “both are to blame for childhood blood lead elevation,” says Rudolph Jaeger, a research professor of environmental medicine at New York University Medical School. Exposure to lead in soil contributes to elevated blood lead, which in turn is associated with reduced educational outcomes.3 Mielke has worked with New Orleans area child-care centers where soil has contained 500–5,000 mg/kg lead. “If we pay attention to environments where children play in the very early years of life, we may reduce their blood lead levels,” Mielke says. Mielke also thinks the current blood lead level of concern of 10 μg/dL—the level at which the Centers for Disease Control and Prevention recommends medical intervention—is too high. Studies show that just 2 μg/dL adversely impacts the heart,4 kidney,5 and child intelligence,6 and many researchers believe there is no safe level of exposure.7 “If we lower this threshold, there may be more interest in primary prevention measures like soil remediation,” Mielke says.

Heavy Metal Contamination of Soils and Vegetation around Solid Waste Dumps in Port Harcourt, Nigeria

Assessment of the levels of copper, zinc and lead in soils and vegetation around solid waste dumpsites in Port Harcourt and environs were carried out in 2005 using Atomic Absorption spectrophotometric technique. Physical parameters such as pH and particle size were also determined. The results show that the mean concentrations of copper in transect and profile soils and vegetation were 1.20 ± 0.83ppm, 2.57 ± 1.87ppm, 1.48 ± 1.61ppm respectively at the East – West road dumpsite and 2.42 ± 1.87ppm, 1.40 ± 0.61ppm, 1.39 ± 0.67ppm respectively at the Kaduna/Afam street dumpsite. The mean concentrations of zinc in soil and vegetations along the transect were 12.83 ± 4.65ppm, 2.68 ± 1.82ppm, 1.33 ± 0.64ppm, 0.80 ± 0.60ppm respectively at the Kaduna/Afam street dumpsite. The mean concentrations of lead in soils and vegetation were 0.26 ± 0.21ppm, 0.28 ± 0.24ppm, 1.48 ± 0.12ppm respectively at the East – West road dumpsite and 0.45 ± 0.37ppm, 0.20 ± 0.08ppm, 0.39 ± 0.17ppm respectively at the Kaduna/Afam street dumpsite. The order of occurrence of the heavy metals in the topsoils of the study areas was Zn > Cu > Pb. The levels of copper and zinc in soils from the waste dumpsite were significantly different (P

Blood Lead Levels And Potental Environmental Exposures Among Children Under Five Years In Kibera Slums, Nairobi

Lead exposure has been associated with intellectual impairment in children in a number of international studies. Prevalence of elevated blood lead levels (eBLL > or = 10ug/dL) of between 5 - 15% has been reported among in Nairobi (UNEP, 2006). However, little is known about potential environmental exposure for eBLLs among children in Kibera, Nairobi. A descriptive, cross-sectional study of children drawn from Kibera slums who presented at Yes to kids (Y2K) programme of VIPS Health Services at Woodley, Nairobi between June and August 2007 was carried out. The study assessed potential correlates of eBLLs in 387 children aged 6 to 59 months and had lived in Kibera slums since birth. Sampling was purposive. The factors examined were age, sex, breastfeeding history, respondent's education and occupation, type of house walls, sources of drinking water and kales, and awareness of lead poisoning among respondents. Potential risk factors such exposure to paint, contaminated playgrounds, glazed pottery, cosmetics and para-occupational as well as living near lead industry and pica behavior were also examined. Potential environmental sources of lead such as drinking water, soil and kales were analyzed for lead levels. Seven percent (n = 27, N = 387) had BLLs above 10ug/dl. BLL > or = 10ug/dl was associated with non-permanent housing (p = 0.812), playing on potentially lead contaminated grounds (p = 0.627) and pica behavior (p = 0.439). Low risk parental occupation (p = 0.001) and Kales sourced from the market/kiosks (p = 0.001) were significantly associated with BLL > or = 10ug/dl. Soil lead levels (Soil Pb) ranged from 3,000 to 90,000ug/kg, which was very high compared to WHO acceptable range of 100 - 200ug/kg. There was weak linear association (r2 = 0.0160) between Soil Pb and mean BLLs for a given village. There were no detectable levels of lead in kales and tap water. The study found about 7% (N = 387) of the children tested had eBLL > or = 10ug/dl in an area with very high soil lead levels (range in Kibera slums: 3,365 - 89,570ug/kg; WHO allowable range: 100 - 120ug/kg), raising a health flag that must be addressed using the multi-sectoral approach and further studies. It's important to note that the study design and its inherent limitations could have masked true picture of childhood lead poisoning in Kibera slums, Nairobi.

Children’s Health: Soil in the City: A Prime Source of Lead

Leaded gas was phased out in 1986, lead-based house paint a decade earlier. As a result, the percentage of U.S. children aged 5 years and younger exceeding the 10-μg/dL blood lead level of concern established by the Centers for Disease Control and Prevention has dropped dramatically. On a national average, the rate fell from over 80% in 1976 to just below 2% in 2002. In many cities, however, it still commonly exceeds 15%. Why? A review published in the August 2008 issue of Applied Geochemistry points to urban soil as a lingering source of lead poisoning in children. Review coauthor Gabriel Filippelli, chair of the Earth Sciences Department at Indiana University–Purdue University, Indianapolis, believes elevated blood lead levels in inner-city children come largely from exposure to lead dust that has settled over decades, resulting in soil whose lead content, at the most contaminated spots, can reach 100 times the background level of about 50 ppm. Children are typically exposed to this lead through play and hand-to-mouth activity. In research published in the 15 December 2007 Science of the Total Environment (which was not included in the review article), Tulane University research professor and environmental toxicologist Howard W. Mielke and colleagues revealed a curvilinear relationship between soil lead in New Orleans and children’s blood lead. The rate of increase was around 3 μg/dL for every 1,000 ppm soil lead above 250–400 ppm, but the rate of increase of blood lead was 4 times higher at soil lead concentrations below 100 ppm. High lead levels damage children’s nervous systems, stunt growth, delay development, and contribute to later-life delinquent behavior. Filippelli mapped soil lead levels near Indianapolis roadways, tracking changes from older inner-city areas toward the newer suburbs. “In places such as the newer neighborhoods, far away from the urban core, where roads weren’t so heavily traveled before leaded gas was eliminated, you have noticeably lower lead levels,” he says. “And when we overlaid a 1990s study of lead poisoning in children to the map we had developed, the distribution of cases fit our pattern precisely.” This study, published with review coauthor Mark A.S. Laidlaw in the June 2005 issue of EHP, also showed that inner-city children had higher blood lead levels in the drier late summer months and lower levels in the winter. “We developed a meteorological prediction model that not only fit the results of our study over ninety percent of the time, but also showed a high degree of correlation with other cities as well,” says Filippelli. The review also looked at options for remediation of lead-contaminated urban soil. Removal of lead-contaminated soils and replacement with clean topsoil can cost more than $1 million per acre, says Filippelli, who proposes two alternatives. “The simplest and least expensive would be a program of high-power shower-spraying of clean water during the months when soil conditions are at their driest, to keep lead-tainted soils from blowing onto horizontal surfaces and into homes.” A second approach would be to put in a layer of clean soil and then hydroseed with grass. Filippelli plans additional experiments in Indianapolis next summer to gain a better picture of the cost and effectiveness of these and other options. “I suspect that Filippelli’s second proposal will be more effective and longer-lasting and—given the water supply issues of many cities—probably more attractive,” says Mielke. In a study reported 15 April 2006 in Environmental Science & Technology, Mielke and colleagues reported success in covering heavily contaminated soils in New Orleans with low-lead alluvium from the Mississippi River. The cost of remediation is certainly a factor, but the cost of inaction is also high. “Aggregate public health costs from lead poisoning in New Orleans alone run more than $70 million annually,” says Mielke, who points to proactive steps being undertaken in Norway. “The Norwegian government has begun testing and remediating soils at day care centers, elementary schools, and parks in major cities, while we dance around issues of responsibility and cost, spending millions in health care costs after using our children as bioindicators.”

Trace elements in home-produced eggs in Belgium: Levels and spatiotemporal distribution

The purpose of this study was to evaluate the levels of arsenic, cadmium, lead, copper and zinc in home-produced eggs, soils and kitchen waste samples of private chicken owners in Belgium, and to determine spatiotemporal differences in trace element contents in eggs. Eggs were sampled in all provinces of Belgium in autumn 2006 and spring 2007. A total number of 59 private chicken owners participated in the study. Trace elements were determined by inductively coupled plasma-mass spectrometry except for mercury, which was determined by atomic absorption of mercury vapour. The mean fresh weight concentrations in eggs in autumn and spring respectively were < 8.0 and < 8.0 µg/kg for arsenic, 0.5 and < 0.5 µg/kg for cadmium, 116 and 74 µg/kg for lead, 0.43 and 0.52 mg/kg for copper, 20.3 and 19.2 mg/kg for zinc, and 3.15 and 4.44 µg/kg for mercury. Analysis of variance determined significant differences in some trace element concentrations in eggs among seasons and regions in Belgium. Average concentrations of arsenic, cadmium and mercury corresponded well with values measured in other countries, while copper and zinc concentrations were within the same order of magnitude as in other countries. Average lead concentrations were high compared to concentrations in eggs from other countries and correlated well with lead concentrations in soil, indicating that the soil is an important source. Other sources of trace elements in eggs might be home-grown vegetables and forage (grass and herbs), and indirectly, air pollution.

Cadmium, Nickel, Chromium, and Lead Levels in Soils and Vegetables under Long‐Term Irrigation with Industrial Wastewater

: The industrial activity areas, rivers, and water sources in neighboring areas are influenced by wastewater of manufacturers. Utilizing water influenced by wastewater increased heavy metals in soils and plants. In 2004, to investigate the effects of wastewater on cadmium (Cd), nickel (Ni), chromium (Cr), and lead (Pb) content in soil and plants, wastewaters of three manufactures (chrome chemical, wood and paper, and textiles) were examined. At harvest time roots, whole shoots (rice, spinach, clover, grass), and rice grain in industrial wastewater–influenced areas and uninfluenced areas were sampled. Soil samples were also taken (0–15, 15–30 cm). Results indicated that when wastewater was discharged into the river water, the concentrations of Cd, Ni, Cr, and Pb increased in river water. Application of river water influenced by industrial wastewater for irrigation of rice and another plants enhanced, the amounts of available Cd, Ni, Cr and Pb in soil. In subsurface horizons (15–30 cm), the concentrations of heavy metals were more than in the surface horizon (0–15 cm). With increasing cation exchange capacity in the soil, the amount of available Cr increased. When the calcium carbonate content in soils was raised, the available Cd and Pb increased in the soil, but Ni and Cr decreased. Meanwhile, organic matter enhanced the concentrations of heavy metals in soil. Accumulations of heavy metals were higher in the roots of rice (control and treatment) than in shoot and rice grain. Cadmium accumulation in rice root was three times that in whole shoot, and grain was two times more than control. The concentrations of Ni, Cr, and Pb in root, whole shoot, and grain of rice were two times higher in industrial wastewater–treated areas. The concentrations of heavy metals in root and whole shoot of spinach, clover, and grass in industrial wastewater area increased about 100%, but not to a toxic level. Cadmium translocated more than other heavy metals from soil to root, whole shoot, and grain of rice, and whole shoot of spinach, clover, and grass.

Lead Concentration in Soil and Trees From an Urban Area

ISEE-896 Objective: To measure the lead levels in soil and trees around an industrial waste storage located in a urban zone in Fresnillo, Zacatecas. Material and Methods: Samples of soil and trees were collected around an industrial storage in the aim to determine the levels of lead concentration. The storage in located inside an urban area, for several years it was utilized to keep wastes produced during the Bi elimination from Pb, where lead is produced as waste. Samples were analyzed using energy dispersive X-ray fluorescence to determine the concentration of lead. Results: Soil samples have lead levels ranging from 354 to 76418 μg/g, the average of lead concentration in the soil samples is 17982 ± 26737 μg/g; those values are above 400 μg/g considered as limit for urban soils by the US Environmental Protection Agency. The samples collected from the trees have lead concentrations ranging from 224 to 5717 μg/g, while the average value is 1878 ± 2264 μg/g. Conclusions: Lead levels found in soil and trees around the industrial storage suggest a contamination risk, mainly through air dispersion; for all the people that live around this facility, this risk is extended beyond the vicinity to the storage through the waste transportation.

Lead in Children's Blood May Contribute to ADHD's Hyperactivity Component

Back to table of contents Previous article Next article Clinical & Research NewsFull AccessLead in Children's Blood May Contribute to ADHD's Hyperactivity ComponentJoan Arehart-TreichelJoan Arehart-TreichelSearch for more papers by this authorPublished Online:2 Nov 2007https://doi.org/10.1176/pn.42.21.0020aThanks to government regulation, lead poisoning in children is no longer common in the United States. However, American youngsters are still widely exposed to low levels of lead in water, soil, and other venues.But even these lower levels of lead in turn may contribute to attention-deficit/hyperactivity disorder (ADHD) in some American children, a new study suggests.The study was headed by Joel Nigg, Ph.D., a professor of clinical psychology at Michigan State University. Results are in press with Biological Psychiatry.Studies done in the 1980s have already linked the amount of lead in children's blood with ADHD. But the levels—10-20 ug/dl—were higher than the levels usually found in American children today, which average 1-2 ug/dl. So Nigg and his colleagues wanted to see whether these lower blood levels could also be associated with ADHD.The researchers recruited subjects for the study from schools, clinics, and advertisements. To obtain the broadest and most representative sample possible, the investigators advertised for both healthy children and children suspected of having or diagnosed with ADHD. A total of 845 families expressed interest in participating in the study.The children in these families were then screened extensively with various instruments—say, the Child Behavior Checklist and the Kiddie Schedule for Affective Disorders and Schizophrenia—to determine whether they had ADHD or other psychiatric disorders.One hundred-and-fifty children aged 8 to 17 were finally selected to participate in the study. A third had ADHD, combined type; a third had ADHD, predominantly inattentive type; and the remainder did not have ADHD and could thus serve as controls. Moreover, the levels of lead in the blood of all the subjects closely matched the American average of 1-2 ug/dl, with a maximum level of 3.4 ug/dl.Blood lead levels were significantly higher in the children with ADHD, combined type, than in the control children, but this was not the case in children who had ADHD, predominantly inattentive type. So Nigg and his group believe that low lead levels in the blood might play a role in the hyperactivity component of ADHD, but not in the inattention component of it.How lead might contribute to hyperactivity is not clear. It does not seem to be mediated by lead's negative impact on intelligence, because while the researchers found that blood lead levels in their subjects were correlated with IQ, they also found that IQ could not explain the link between lead and hyperactivity. Low-level lead exposure is known to disrupt mid-brain dopamine circuitry, and this circuitry, however, is involved in ADHD.Although the researchers suspect that low blood levels of lead may play a role in a number of cases of ADHD-related hyperactivity, they do not believe that this is so in all cases, because some of their subjects with mildly elevated blood levels did not have ADHD-related hyperactivity, while some of their subjects with ADHD-related hyperactivity did not have elevated blood levels of lead.The study's results have public health policy implications, Nigg told Psychiatric News, emphasizing that “prevention of lead exposure may be important at even lower levels than we thought.”The study was financed by Michigan State University and the Centers for Disease Control and Prevention.An abstract of “Low Blood Lead Levels Associated With Clinically Diagnosed Attention-Deficit/Hyperactivity Disorder and Mediated by Weak Cognitive Control” is posted at<www.journals.elsevierhealth.com//periodicals/bps> under “Articles in Press.” ▪ ISSUES NewArchived

Lead Analysis in Soils and Sediments at the Saginaw Field and Stream Club

Samples from the Saginaw Field and Stream Club in Saginaw County, Michigan, were collected to determine whether lead levels at the club shooting ranges pose a threat to the environment. Flame atomic absorption spectroscopy (AAS) was used to determine lead levels in soil and sediment samples digested for total lead as well as soluble lead. Lead was present at levels exceeding 10,000 mg/kg in some surface soil samples. In general, lead was pervasive at the site in both metallic and soluble forms. Each of the shooting ranges contains areas where lead occurs at concentrations significantly in excess of the Michigan Department of Environmental Quality criteria and therefore poses a potential risk to the human users of the land as well as to the native wildlife.

Northern Idaho House Dust and Soil Lead Levels Compared to the Bunker Hill Superfund Site

House dust has been identified as a major exposure medium for lead (Pb) in children. High levels of Pb in soil and house dust have been recorded at the Bunker Hill Superfund Site (BHSS) in northern Idaho, an historic mining and smelting district. Soil and dust remediation at the site was required; however, regional background soil and dust Pb levels had not been well characterized. The objective of this survey was to determine background house dust Pb levels and to compare those levels with concentrations, and dust and Pb loading rates measured at the BHSS. Soil and house dust samples were collected in five towns demographically similar to the BHSS but unaffected by the mining industry. The background concentrations and loading rates were significantly lower than those observed at the site. House age was a significant factor affecting background soil and house dust Pb concentrations and loading rates.

Is lead toxicity still a risk to U.S. children?

Elevated blood-lead levels put children at risk for neurobehavioral-cognitive deficits, such as IQ deficiency, behavioral disorders and impaired hearing. We examined several factors that contribute to elevated lead levels in U.S. children to help define the extent to which lead toxicity from these sources continues to be a problem. The results of our review suggest that elevated levels of lead in paint, dust, soil, imported pottery and ceramic ware, ethnic remedies, and some imported candies continue to be areas of concern, while typical levels in food products appear to be acceptable. It is important to continue monitoring lead levels in children as well as in environmental and food sources.

Screening Epidemiological Study:Blood Lead Levels In The Vicinity Of A Lead Smelter

The private sector lead smelting industry in Cairo has traditionally been located in a northern suburb, Shoubra el-Kheima. Originally an industrial zone, over time residential blocks have filled in the neighborhood, until now it is one of the country’s most densely populated areas. The largest of these smelters is the Awadallah Secondary Lead Smelter, which began operation in 1979, and ceased smelting activities in 2001 as the Government of Egypt (GOE) encouraged smelters to move to new industrial zones and install up-to-date technology to reduce harmful emissions from the smelting process. Since 2001, the smelter facility has been used to refine and manufacture lead products. Knowing the ‘state of the site’, however, is only one part of the picture. It is also necessary to ascertain that the smelter imposed no adverse health effects on the people living in proximity to the smelter due to the high levels of lead contamination that exists in the study area. A screening epidemiological study determining blood lead levels—the best available index of body lead load—was conducted to provide further information on the potential impacts of lead contamination in the vicinity of the Awadallah Smelter. This allowed determination of the effect of environmental lead on the blood lead levels of children younger than 7 years of age (the most vulnerable to the harmful effects of lead), on females of reproductive age and on adult males. The study investigated the relationship between the blood lead levels of the target population with lead contamination of the indoor environment—household dust, drinking water, and interior paint. It was found that the outdoor environment, especially lead contamination of the soil, was the primary cause of elevated blood lead levels in residents. The lead levels of the test group varied from one zone to another, depending on soil lead levels. Another study was done three years after shutting down the smelter and cleaning a children’s school situated in the study area, it was found that the blood lead level for most of the children in the school was within the allowable limit. © 2006 WIT Press WIT Transactions on Ecology and the Environment, Vol 86, www.witpress.com, ISSN 1743-3541 (on-line) Air Pollution XIV 761 doi:10.2495/AIR06075

The effectiveness of low-cost soil treatments to reduce soil and dust lead hazards: The Boston lead safe yards low cost lead in soil treatment, demonstration and evaluation

The Boston lead safe yards low cost lead in soil treatment, demonstration, and evaluation was developed to explore the viability and effectiveness of low-cost soil interventions to reduce exposure to soil lead hazards. Buildings that had been abated for lead to Massachusetts's deleading standards in the previous 5 yrs and met other program requirements were recruited for the evaluation. Following individual property assessments, yards were treated with application of ground coverings and ground barriers in 2000–2001 and followed up at 1 yr. The treatment cost ranged from $1095 to $5643 with an average of $2798. Soil lead levels at the building dripline, measured with a field-portable X-ray fluorescence analyzer (Niton Model 702 Spectrum Analyzer), dropped from 2021 PPM at baseline to 206 PPM at 1-yr follow-up. Most of the barrier treatments continued to block access to the lead-contaminated soil at 1 yr. At the follow-up, few properties with grass treatment had areas that were completely bare, but 28% had more than a small amount of treated areas bare. Treatments were effective in reducing entryway dust lead in the rear of the building if the residents reported they had maintained the yard treatments. Each additional yard work activity reported was predicted to lower 1-yr floor dust lead loading at the rear common/main and dwelling unit entries by about 20%. Each additional 100 ft 2 of yard treated was predicted to lower 1-yr floor dust loading at the rear dwelling unit entry by 19%. Treatments did not show a dust lead effect at 1 yr in the front entryway of the building, but the investigators believe that this may be due to the effect of resident cleaning overshadowing the treatment effect.