Dust Lead Levels Research Articles

Assessing the Relationship Between Environmental Lead Concentrations and Adult Blood Lead Levels

This paper presents a model for predicting blood lead levels in adults who are exposed to elevated environmental levels of lead. The model assumes a baseline blood lead level based on average blood lead levels for adults described in two recent U.S. studies. The baseline blood level in adults arises primarily from exposure to lead in diet. Media-specific ingestion and absorption parameters are assessed for the adult population, and a biokinetic slope factor that relates uptake of lead into the body to blood lead levels is estimated. These parameters are applied to predict blood lead levels for adults exposed to a hypothetical site with elevated lead levels in soil, dust and air. Blood lead levels ranging from approximately 3-57 micrograms/dl are predicted, depending on the exposure scenarios and assumptions.

Cadmium and Lead Levels in House Dust from Smokers' and Non-Smokers' Homes Related to Nicotine Levels

In children there is an association between environmental tobacco smoke exposure and blood lead levels. One possible explanation is a contamination of house dust by cigarette ash and smoke, since several studies have shown that house dust is a source of lead exposure. Thus, house dust samples from the vacuum cleaner sacks from 72 homes in the city of Copenhagen were ana lysed for cadmium (Cd) and lead (Pb). The lead concentration was higher in fine than in coarse fraction (medians 190 vs. 140 μg/g; p = 0.0001). For cad mium the median concentrations were 5.0 μg/g in both fractions. No statisti cally significant association was found between the smoking habits, the socio- economic status of the residents, the presence of wall-to-wall carpets, or dust nicotine levels, on the one hand, and the metal levels in the house dust, on the other. Thus, tobacco is not an important source of contamination of house dust with lead and cadmium. However, high levels found in some samples indicate that house dust may be a significant source of lead and cadmium exposure, in some small children.

An evaluation of experimental practices for abatement of residential lead-based paint: Report on a pilot project

In this pilot study, we prospectively evaluated experimental practices for abating lead-based paint in six dwellings. These experimental abatements were based upon a new approach to abatement which reflects current understanding of low-level lead toxicity in children and the role of lead-contaminated dust as an important contributor to children's total body burden. Our previous study of traditional abatement practices in Baltimore showed them to be inadequate for reducing lead in both house dust and children's blood. Our experimental abatements resulted in significant reductions in house dust-lead levels (PbD) which persisted during 6-9 months of followup. Geometric mean PbD at floors, window sills, and window wells were respectively 5.6, 49.6, and 316.7 mg/m2 at preabatement, and respectively 0.6, 4.4, and 10.8 mg/m2 at 6-9 months. Experimental abatements involved (1) treatment of lead-painted surfaces above and below 4 ft from the floor, including interior and exterior components of windows; (2) sealing or covering of wooden floors; (3) procedures for containment of dust during abatement; and (4) a final cleanup using a high-efficiency particle air (HEPA) vacuum. We recommend that more research be done to further evaluate and compare the long-term efficacy of these and other abatement methodologies.

Health and environmental outcomes of traditional and modified practices for abatement of residential lead-based paint.

We evaluated traditional and modified practices for abating lead-based paint in homes of children with blood-lead concentrations (PbB) greater than 1.4 mumol/L (greater than 29 micrograms/dl). Traditional abatement resulted in acute increases in: 1) lead contaminated house dust (generally 3 to 6-fold over pre-abatement levels, but at abated sites typically 10 to 100-fold); and 2) the PbBs of nearly half of the occupant children. Modified practices represented modest short-term improvement compared to traditional practices but were also inadequate. By six months, it was clear that neither form of abatement resulted in long-term reductions of PbB or house dust lead levels, leaving children at continued risk of excessive exposure to lead and permanent adverse neurobehavioral effects. Windows were found to be high sources of lead contaminated house dust. Recommendations are made for improved abatement practices including more complete abatement of window units and more effective clean-up to remove lead-bearing dust. Thirteen million US children live in lead-painted dwellings. Research is needed to identify abatement strategies that will be practical and well suited to the current understanding of low-level lead toxicity.

Lead poisoning among household members exposed to lead-acid battery repair shops in Kingston, Jamaica.

To investigate the risk of lead poisoning among household members exposed to 'backyard' battery repair shops (BBRS) in Kingston, Jamaica, environmental and blood lead (PbB) were measured at 24 households (112 individuals) with a BBRS worker or located at a BBRS premises and at 18 neighbourhood control households (74 individuals). Elevated PbB (greater than or equal to 25 micrograms per decilitre [micrograms/dl]) was common among subjects of all ages living at BBRS premises, especially among children less than age 12, 43% of whom had PbB greater than 70 micrograms/dl. Potentially hazardous soil and house dust lead levels were also common at BBRS premises, where 84% of yards had soil lead levels above 500 parts per million (geometric mean 3388 parts per million [ppm] at BBRS premises households with a BBRS worker). Geometric mean blood and environmental lead levels were significantly lower at control households, where less than 10% of subjects in all age groups had elevated PbB (maximum 33 micrograms/dl). Sharing a premises with a BBRS was a stronger determinant of household blood lead and environmental contamination than was the presence of a BBRS worker in a household. Blood lead levels were associated with soil and house dust lead levels in all age groups. We conclude that small battery repair shops, which have also been described in other developing countries, create a high lead poisoning risk for nearby residents.

Lead-based paint in dwellings: The potential for contamination of the home environment during renovation

The quantity and particle size characteristics of lead in dust released during three different paint removal techniques was determined under controlled conditions and in situ in a dwelling. Air-lead and deposited dust-lead levels were highest after sanding but 'burning-off' and 'hot-air' removal methods also produced significant contamination. The importance of dust particle-size and lead is discussed in relation to the potential hazard to home renovators via inhalation and to children via the 'hand-to-mouth' route.

Lead levels in dust at roadside recreational areas of Hong Kong

Lead levels in dust at roadside recreational areas of Hong Kong

The influence of social and environmental factors on dust lead, hand lead, and blood lead levels in young children

The roles of environmental and behavioral factors in determining blood lead levels were studied in a cohort of young children living in an urban environment. The subjects were observed at 3-month intervals from birth to 24 months of age. Repeated measurements were made of the children's blood lead levels, environmental levels of lead in house dust, and in the dust found on the children's hands. A qualitative rating of the residence and of the socioeconomic status of the family was obtained. Interviews and direct observation of parent and child at home were used to evaluate various aspects of caretaker-child interactions. Data analysis consisted of a comparison of results obtained by (a) simple correlational analysis, (b) multiple regression analysis, and (c) structural equations analysis. The results demonstrated that structural equation modeling offers a useful approach to unraveling the complex interactions present in the data set. In this preliminary analysis, the suspected relationship between the levels of lead in house dust and on hands and the blood lead level was clearly demonstrated. Furthermore, the analyses indicated an important interplay between environmental sources and social factors in the determination of hand lead and blood lead levels in very young children.

Condition and type of housing as an indicator of potential environmental lead exposure and pediatric blood lead levels

Environmental evaluations in a prospective behavioral study of children with blood lead levels up to about 50 μg/dl were performed by an intensive environmental survey and by exterior visual evaluation of housing quality. Serial blood lead values for infants in the study were compared to exterior housing type and quality, which itself was also compared with results of the intensive environmental evaluation. Five housing condition and type categories were defined: public housing; private housing (satisfactory, deteriorated, and dilapidated); and rehabilitated private housing. In this interim report on the first subset of available data, the housing categories were found to differ in paint and environment dust lead levels, with public and rehabilitated housing having lowest values. Blood lead concentrations of children differed across housing categories as early as 6 months of age, with children residing in public housing having lowest levels, followed by those in rehabilitated housing. The spread in mean blood lead concentrations among the housing quality categories increased with increasing age of the children. Housing category accounted for over one-half of the blood lead variability in 18-month-old children.

Contribution of lead in dust to children's blood lead.

The importance of urban dust as a source of lead for young children is still disputed. Although blood-lead data from various population surveys usually show a peak concentration in early childhood, there is evidence that such a peak is small or absent altogether in children without much access to the general environment. An examination of those studies where groups of people in regions of low and high lead contamination have been compared shows that the child/adult blood-lead ratio is almost always enhanced in the more exposed groups. This implies a route of lead uptake which is important for children but less so for adults, and it is likely that this route is the dust-hand-mouth one. There are sufficient data to suggest a quantitative relationship between raised levels of blood lead and lead in dust. There is a strong case for a lead-in-dust standard but some will probably remain unpersuaded unless or until there are reliable data for blood lead and environmental lead involving matched groups of young people from urban and rural areas.

El Paso Revisited

Increased lead absorption was found in 1972 in 56% of 256 children aged 1 to 18 years who lived within 1.6 km of a lead-emitting ore smeltery in El Paso, Tex. Engineering improvements have subsequently reduced emissions from the smeltery, and levels of lead in air, dust, and soil have declined. To evaluate the impact of these environmental improvements on lead absorption, we conducted a follow-up study in 1977 of blood lead levels in 140 children aged 1 through 18 years who lived within 1.6 km of the smeltery. Mean blood lead levels were found to have decreased from 41.4 to 17.7 μg/dL in children living within 0.8 km of the plant and from 31.2 to 20.2 μg/dL in children living at 0.8 to 1.6 km. These data argue for the feasibility of reducing children's lead absorption near primary lead smelteries. (<i>JAMA</i>242:739-741, 1979)

El Paso revisited. Epidemiologic follow-up of an environmental lead problem

Increased lead absorption was found in 1972 in 56% of 256 children aged 1 to 18 years who lived within 1.6 km of a lead-emitting ore smeltery in El Paso, Tex. Engineering improvements have subsequently reduced emissions from the smeltery, and levels of lead in air, dust, and soil have declined. To evaluate the impact of these environmental improvements on lead absorption, we conducted a follow-up study in 1977 of blood lead levels in 140 children aged 1 through 18 years who lived within 1.6 km of the smeltery. Mean blood lead levels were found to have decreased from 41.4 to 17.7 microgram/dL in children living within 0.8 km of the plant and from 31.2 to 20.2 microgram/dL in children living at 0.8 to 1.6 km. These data argue for the feasibility of reducing children's lead absorption near primary lead smelteries.

Increased lead absorption with anemia and slowed nerve conduction in children near a lead smelter

Studies to evaluate the prevalence, sources, and health consequences of lead absorption were conducted among children living near a primary lead smelter. Lead levels in air, soil, and dust were highest at the smelter and decreased with distance. Ninety-nine percent of one- to nine-year-old children living within 1.6 kilometers had blood lead levels greater than or equal 40 mug/dl, indicating increased absorption, and 22% had levels greater than or equal 80 mug/dl. The prevalence of lead levels greater than or equal 40 mug/dl decreased with distance; at 72 kilometers from the smelter it was 1%. Erythrocyte protoporphyrin levels increased with blood lead levels: 17% of children with lead levels of greater than or equal 80 mug/dl were anemic. There was no overt neurologic toxicity. Significant negative correlation was found in 202 five- to nine-year-old children between blood lead levels and motor nerve conduction velocity (r = 0.38, p less than 0.02).