Blood Lead Survey of Children,Pregnant Women,Professional Drivers,Street Workers,and Office Workers in Trujillo,Peru

In this pilot study, conducted in summer 2002, the authors measured blood lead levels (BLLs) for 118 subjects in the city of Trujillo, Peru, where leaded gasoline is in the process of being phased out. Subjects included bus drivers, combi (minivan) drivers, street vendors, newspaper vendors, traffic police, taxi drivers, gas station attendants, children living both near and distant from gas stations, pregnant women, and office workers (controls). The highest BLLs were 9.2 μg/dl and 9.3 μg/dl from a child who lived near a gas station and from a traffic policeman, respectively; however, all BLLs were below the U.S. Centers for Disease Control and Prevention's advisory level of concern (10 μg/dl). Office workers (n = 8) and pregnant women (n = 36) had significantly lower BLLs (geometric mean ± standard deviation = 2.1 ± 0.7 μg/dl, p < 0.022; and 2.5 ± 1.1 μg/dl, p < 0.008, respectively) than total traffic-exposed workers (n = 48; 3.2 ± 1.8 μg/dl). BLLs of children living near gas stations (n = 17; 3.7 ± 2.2 μg/dl) were marginally higher (p = 0.07) than for children not living near gas stations (n = 9; 2.9 ± 1.1 μg/dl). The study was limited by small sample size and the fact that the data were based on a convenience sample not fully representative of the cohorts studied. Nevertheless, the authors' findings suggest that leaded gasoline use in Trujillo continues to affect BLLs in traffic-exposed populations.     

Traffic-related occupational exposures to PM2.5, CO, and VOCs in Trujillo, Peru

A traffic-related exposure study was conducted among 58 workers (drivers, vendors, traffic police, and gas station attendants) and 10 office workers as controls in Trujillo, Peru, in July 2002. PM2.5 was collected, carbon monoxide (CO) was measured, volatile organic compounds (VOCs) were sampled and analyzed. Newspaper vendors had the highest full-shift CO exposures (mean +/- SD: 11.4 +/- 8.9 ppm), while office workers had the lowest (2.0 +/- 1.7 ppm). Bus drivers had the highest full-shift PM2.5 exposures (161 +/- 8.9 microg/m3), while gas station attendants (64 +/- 26.5 microg/m3) and office workers (65 +/- 8.5 microg/m3) were the lowest. Full-shift benzene/toluene/ethylbenzene/xylene exposures (BTEX) among gas station attendants (111/254/43/214 microg/m3) were much higher than those among van and taxi drivers. Several of the traffic-related occupational exposures studied were elevated and are of occupational health concern.     

Blood lead levels of primary-school children in Penghu County,Taiwan: distribution and influencing factors

OBJECTIVES: The purpose of this study was to investigate the blood lead levels (BLLs) of primary-school children aged 7 to 12 in Penghu island and to determine the factors affecting their BLLs. METHODS: A total of 1,885 participants were recruited and BLLs were measured with a flameless atomic absorption spectrophotometer. A questionnaire was used to collect personal information. RESULTS: The results indicated that the mean BLL of primary-school children in Penghu was 6.0+/-2.4 microg/dl (1.0 approximately 29.3 microg/dl). The mean BLL of schoolboys ( n=1,046) was 6.3+/-2.6 microg/dl, with a maximum of 29.3 microg/dl, while the mean BLL of schoolgirls ( n=839) was 5.7+/-2.2 microg/dl, with a maximum of 23.4 microg/dl. Risk-factor analysis showed that personal characteristics (i.e., gender, frequency of milk consumption, grade levels) and geographic factors (i.e., levels of urbanization) significantly influence the BLLs. However, there was no significant impact on BLLs from drinking water, residential distance from a major road, and living close to lead-emitting sources. CONCLUSIONS: Geographical factors were highly associated with BLLs. The BLLs of the primary-school children living in the main Penghu island were lower than those in the other small islands.     

Use of isotope ratios to identify sources contributing to pediatric lead poisoning in Peru

In 1998, a school-based blood lead level (BLL) survey of 2,510 children, conducted in Lima and Callao, Peru, revealed elevated BLLs in children from 2 Callao schools (mean BLL = 25.6 microg/dl; n = 314) and in children from Callao overall (mean BLL = 15.2 microg/dl; n = 898), compared with children from Lima (mean BLL = 7.1 microg/dl; n = 1,612). Public health officials at Peru's Direccion General de Salud Ambiental (DIGESA) hypothesized that a possible source of the elevated pediatric BLLs observed in Callao was a large depository near the port where mineral concentrates are stored prior to shipment. The U.S. Centers for Disease Control and Prevention worked with DIGESA to identify source(s) that contributed to the pediatric lead poisonings by comparing isotopic profiles of lead in blood, mineral, gasoline, and air filter samples. The lead isotope ratio (IR) observed in mineral samples from the depository in Callao differed from those in gasoline samples from Lima and Callao. The blood lead IRs of children living near the depository were similar to the IRs of the mineral samples and different from the IRs of the gasoline samples, suggesting that lead from the depository-and not gasoline-was the primary source of lead in these children. Lead IR analysis of regional air filter samples supported these findings.     

Preschool children's lead levels in rural communities of Zhejiang province, China

The aim of the study was to determine mean blood lead levels (BLLs) and prevalence of elevated BLLs among preschool children aged 3-6 years in Zhejian rural communities, China. Data were gathered by means of a questionnaire and blood lead analyses for 217 children who attended six randomly selected kindergartens. BLLs ranged from 25-437 microg/l. Arithmetic mean was 95 microg/l and standard deviation was 56 microg/l. BLLs of 63 samples (29.0%) were > or =100 microg/l. Children with BLLs > or =100 microg/l came from families with a higher proportion of their fathers or mothers working in conditions of potential exposure to lead, as compared to those with BLLs <100 microg/l (P < 0.01). A significantly higher proportion of children with BLLs > or =100 micro/l lived in buildings that were located near small industries, such as mechanics, furniture, or paint shop, as compared to those with BLLs <100 microg/l (P < 0.01). In conclusion, the data indicate that high levels of childhood lead exposures even prevail in rural communities and deserve authorities' attention. With the recent ban of leaded gasoline in China, emphasis should shift to other sources of exposure in children.     

Blood lead levels and risk factors for lead poisoning among children in a Mexican smelting community

The authors evaluated mean blood lead levels (BLLs) and the prevalence of elevated BLLs in children 1-6 yr of age living in Torreón, Mexico, and assessed risk factors for lead exposure in these children. The study involved a simple random sample of households in the area around a local smelter, as well as a 2-stage cluster sample of neighborhoods and households in the remainder of Torreón. The geometric mean BLL of children in this study (N = 367) was 6.0 microg/dl (95% confidence interval [CI] = 5.2, 6.8) (0.29 microM/l [95% CI = 0.25, 0.33]). Twenty percent of the children had BLLs > or = 10 microg/dl (0.48 microM/l), and 5% had BLLs > or = 20 microg/dl (0.97 microM/l). In multivariate analyses, distance from the smelter, amount of income, and education level of the primary caregiver predicted BLLs. In the environmental risk factor subsample (n = 124), dust and soil lead levels were associated with BLLs and distance from the smelter. BLLs in this study were moderately high, but the levels were lower than those in other smelting communities prior to remediation.     

Childhood lead exposure in the palestinian authority, Israel, and Jordan: results from the Middle Eastern regional cooperation project, 1996-2000

In the Middle East, the major sources of lead exposure have been leaded gasoline, lead-contaminated flour from traditional stone mills, focal exposures from small battery plants and smelters, and kohl (blue color) in cosmetics. In 1998-2000, we measured blood lead (PbB) levels in children 2-6 years of age in Israel, Jordan, and the Palestinian Authority (n = 1478), using a fingerstick method. Mean (peak; percentage > 10 microg/dL) PbB levels in Israel (n = 317) , the West Bank (n = 344), Jordan (n = 382) , and Gaza (n = 435) were 3.2 microg/dL (18.2 ; 2.2%) , 4.2 microg/dL (25.7; 5.2%), 3.2 microg/dL (39.3; < 1%) , and 8.6 microg/dL (> 80.0; 17.2%), respectively. High levels in Gaza were all among children living near a battery factory. The findings, taken together with data on time trends in lead emissions and in PbB in children in previous years, indicate the benefits from phasing out of leaded gasoline but state the case for further reductions and investigation of hot spots. The project demonstrated the benefits of regional cooperation in planning and carrying out a jointly designed project.     

Blood lead levels among children of lead-exposed workers: A meta-analysis.

BACKGROUND: To further assess the utility of targeted blood lead screening for children from households with members having occupational lead exposures, we conducted a meta-analysis of all available reports of take-home lead exposures. Our objective was to estimate the blood lead levels among U.S. children (ages 1-5) from households with lead-exposed workers. METHODS: Reports considered for inclusion were cited in Medline, Toxline, Excerpta Medica, and Bio-Med plus all unpublished reports available at the National Institute for Occupational Safety and Health through 1994. The a priori criteria for inclusion of U.S. reports required their having data on: (1) venous blood lead levels for children, (2) children's ages, (3) data for at least five children, (4) workers' occupations, (5) workers' blood lead levels, and (6) data collection methods. RESULTS: Based on a meta-analysis of 10 reports from 1987 through 1994, the children (n=139) of lead-exposed workers (n=222) had a geometric mean blood lead level of 9.3 microg/dL compared to a U.S. population geometric mean of 3.6 microg/dL (P=0.0006). Also in this group, 52% of the children had blood lead levels (BLLs) >/= 10 microg/dL compared to 8.9% in the U.S. (P=.0010), and 21% of the children had BLLs >/= 20 microg/dL compared to 1.1% in the U.S. (P=. 0258). CONCLUSIONS: We estimate, based on 1981-83 survey data, that there are about 48,000 families with children under six living with household members occupationally exposed to lead. If the findings from this meta-analysis (admittedly limited by small numbers) are generalizable, about half of the young children in these families may have BLLs >/= 10 microg/dL. Data were too sparse to determine if children of workers with elevated blood leads were at greater risk than children whose parents were only known to be lead exposed. Our findings support the position that children of lead-exposed workers should be targeted for blood lead screening. Am. J. Ind. Med. 36:475-481, 1999. Published 1999 Wiley-Liss, Inc.     

Blood lead levels in children after phase-out of leaded gasoline in Kinshasa,the capital of Democratic Republic of Congo (DRC)

Background

The phasing out of lead from gasoline has resulted in a significant decrease in blood lead levels (BLLs) in children during the last two decades. Tetraethyl lead was phased out in DRC in 2009. The objective of this study was to test for reduction in pediatric BLLs in Kinshasa, by comparing BLLs collected in 2011 (2 years after use of leaded gasoline was phased out) to those collected in surveys conducted in 2004 and 2008 by Tuakuila et al. (when leaded gasoline was still used).

Methods

We analyzed BLLs in a total of 100 children under 6 years of age (Mean ± SD: 2.9 ± 1.6 age, 64% boys) using inductively coupled argon plasma mass spectrometry (ICP – MS).

Results

The prevalence of elevated BLLs (≥ 10 μg/dL) in children tested was 63% in 2004 [n = 100, GM (95% CI) = 12.4 μg/dL (11.4 – 13.3)] and 71% in 2008 [(n = 55, GM (95% CI) = 11.2 μg/dL (10.3 – 14.4)]. In the present study, this prevalence was 41%. The average BLLs for the current study population [GM (95% CI) = 8.7 μg/dL (8.0 – 9.5)] was lower than those found by Tuakuila et al. (F = 10.38, p <0.001) as well as the CDC level of concern (10 μ/dL), with 3% of children diagnosed with BLLs ≥ 20 μg/dL.

Conclusion

These results demonstrate a significant success of the public health system in Kinshasa, DRC-achieved by the removal of lead from gasoline. However, with increasing evidence that adverse health effects occur at BLLs < 10 μg/dL and no safe BLLs in children has been identified, the BLLs measured in this study continue to constitute a major public health concern for Kinshasa. The emphasis should shift to examine the contributions of non-gasoline sources to children’s BLLs: car batteries recycling in certain residences, the traditional use of fired clay for the treatment of gastritis by pregnant women and leaded paint.     

Ten-year follow-up of blood lead levels with medical removal protection of shipyard workers

This cases report compared the short-term changes of BLL with medical removal intervention and follow-up the long-term changes of BLL afterward. During a physical examination in October 1992, a 44-year old shipyard welder was discovered to have a blood lead level (BLL) of 54.1 microg/dl. It was recommended that the shipyard remove this worker from his workplace. In 1993 the BLLs checked for this worker were 36.7 microg/dl in March and 32.0 microg/dl in April. After six months of medical removal, he returned to initial welding work. In 2002, we collected two blood samples from this worker for analysis in May and October. The results were 30.4 microg/dl and 31.6 microg/dl, respectively. Meanwhile, two other welding workers (case 2 and case 3) with BLLs over 40 microg/dl in the survey conducted at the same shipyard in 1992. It took 4 yr to let BLLs downed to less than 40 microg/dl. However, after the blood lead concentration drops to below 40 microg/dl, 10 yr long-term observation indicates that BLLs reduction level off and do not continue to go down in these three cases.     

Pattern of blood lead levels over working lifetime and neuropsychological performance

The authors examined the impact on neuropsychological performance of past high lead exposure, followed by lower proximate lead exposure, in 2 groups of smelter workers selected on the basis of their patterns of blood lead levels (BLLs) over time. Prior to 1980 (past exposure), both groups had more than 90% of their BLLs > or = 40 microg/dl. During and subsequent to 1980 (proximate exposure), those subjects with more than 90% of their BLLs remaining at > or = 40 microg/dl were assigned to the high-high (H-H) pattern group (n = 40); whereas those with 90% of levels below 40 microg/dl were assigned to the high-low (H-L) pattern group (n = 40). Means (and standard deviations) for pre-1980 time-integrated blood lead (IBL) levels were similar for the H-H pattern [633.2 (202.2) microg/yr-dl] and the H-L pattern [556.5 (144.8) microg/yr x dl]; however, IBLs from 1980 on were significantly different [H-H pattern = 646.9 (58.70) microg/yr x dl and H-L pattern = 408.8 (46.37) microg/yr x dl; p < 0.0001]. Age, education, and years of employment were similar for both groups. Examination of 5 neuropsychological measures revealed that verbal memory was significantly better in the H-L pattern group than in the H-H group. Multivariate examination of the data showed that pattern of exposure contributed significantly to verbal memory performance, after adjustment for the covariates, current BLL, and IBL. A partial correlation analysis between verbal memory and IBL for past high exposure showed an association with H-H pattern, but none with H-L pattern. Pattern of BLLs over a working lifetime contributed unique variance to verbal memory. Absence of an association between past high lead exposure and verbal memory in the H-L pattern group suggests that reversibility of function may occur when proximate BLL is maintained below 40 microg/dl.     

Indirect lead exposure among children of radiator repair workers

BACKGROUND: Secondary exposure to lead has been identified as a public health problem since the late 1940s; we investigate the risk of lead exposure among families of radiator repair workers. METHODS: A sample of the wives and children, aged 6 months to 6 years (exposed children) (n = 19), of radiator repair workers and a sample of children whose parents were not occupationally exposed to lead (non-exposed children) (n = 29) were matched for age and residence; their geometric mean blood lead levels are compared. Blood samples were obtained by the finger stick method and environmental dust samples by the wipe method; both were analyzed using a portable anodic stripping voltameter. RESULTS: Dust lead levels were significantly higher in the houses of exposed children (143.8 vs. 3.9 microg/g; P < 0.01). In crude analyses, the highest lead levels were observed among children whose fathers worked in home-based workshops (22.4 microg/dl)(n = 6). Children whose fathers worked in an external workshop (n = 13) also had high levels (14.2 microg/dl) (P < 0.01), while blood lead levels in non-exposed children were significantly lower (5.6 microg/dl)(P < 0.01). The observed differences remained significant after adjustment for age and gender. CONCLUSIONS: This study confirms that children of radiator repair workers are at increased risk of lead exposure and public health interventions are needed to protect them.     

Traffic-related Occupational Exposures to PM2.5, CO,and VOCs in Trujillo,Peru

Abstract

A traffic-related exposure study was conducted among 58 workers (drivers, vendors, traffic police, and gas station attendants) and 10 office workers as controls in Trujillo, Peru, in July 2002. PM_2.5 was collected, carbon monoxide (CO) was measured, volatile organic compounds (VOCs) were sampled and analyzed. Newspaper vendors had the highest full-shift CO exposures (mean ± SD: 11.4 ± 8.9 ppm), while office workers had the lowest (2.0 ± 1.7 ppm). Bus drivers had the highest full-shift PM_2.5 exposures (161±8.9 pg/m³), while gas station attendants (64 ± 26.5 pg/m³) and office workers (65 ± 8.5 μg/m³) were the lowest. Full-shift benzene/toluene/ethylbenzene/xylene exposures (BTEX) among gas station attendants (111/254/43/214 μg/m³) were much higher than those among van and taxi drivers. Several of the traffic-related occupational exposures studied were elevated and are of occupational health concern.     

Binational study of pediatric blood lead levels along the United States/Mexico border

To evaluate lead exposure among children living in border communities, the states of Arizona and New Mexico in the United States (US), and the states of Sonora and Chihuahua in Mexico collaboratively requested that the Centers for Disease Control and Prevention (CDC) provide technical assistance to document pediatric blood lead levels (BLLs) in children living along this part of the US/Mexico border. Two studies were conducted to evaluate BLLs of children aged 1-6 years. In 1998, 1210 children were tested in the Arizona/Sonora study; in 1999, 874 children were tested in New Mexico/Chihuahua. Overall geometric mean BLL was 32.5 microg/l (95% Confidence Interval 31.5-33.5) with BLLs ranging from below limit of detection to 320.0 microg/l. Mean BLLs were higher among children living on the Mexican side of the border (43.2 microg/l) compared to those on the US side (22.3 microg/l). Mean BLLs ranged from 14.9 to 31.2 microg/l at the US sites and from 26.9 to 55.2 microg/l at the Mexican sites. This study used a convenience sample and cannot be considered representative of the general population. Nonetheless, the range of mean BLLs among the sites and especially the higher mean BLLs among children living in the border communities in Mexico suggests different exposures to lead and warrants further attention.     

Environmental exposure to volatile organic compounds among workers in Mexico City as assessed by personal monitors and blood concentrations.

Benzene, an important component in gasoline, is a widely distributed environmental contaminant that has been linked to known health effects in animals and humans, including leukemia. In Mexico City, environmental benzene levels, which may be elevated because of the heavy traffic and the poor emission control devices of older vehicles, may pose a health risk to the population. To assess the potential risk, portable passive monitors and blood concentrations were used to survey three different occupational groups in Mexico City. Passive monitors measured the personal exposure of 45 workers to benzene, ethylbenzene, toluene, o-xylene and m-/p-xylene during a work shift. Blood concentrations of the above volatile organic compounds (VOCs), methyl tert-butyl ether, and styrene were measured at the beginning and the end of a work shift. Passive monitors showed significantly higher (p > 0.0001) benzene exposure levels among service station attendants (median = 330 microg/m3; range 130-770) as compared to street vendors (median = 62 microg/m3; range 49-180) and office workers (median = 44 microg/m3, range 32-67). Baseline blood benzene levels (BBLs) for these groups were higher than those reported for similar populations from Western countries (median = 0.63 microg/L, n = 24 for service station attendants; median = 0.30 microg/L, n = 6 for street vendors; and median = 0.17 microgr;g/L, n = 7 for office workers). Nonsmoking office workers who were nonoccupationally exposed to VOCs had BBLs that were more than five times higher than those observed in a nonsmoking U.S. population. BBLs of participants did not increase during the work shift, suggesting that because the participants were chronically exposed to benzene, complex pharmacokinetic mechanisms were involved. Our results highlight the need for more complete studies to assess the potential benefits of setting environmental standards for benzene and other VOCs in Mexico.     

Blood lead levels in children, China

To evaluate Chinese children's blood lead levels (BLLs) and identify its distribution features, we collected articles on children's BLLs published from 1994 to March 2004 using the Chinese Biomedical Disc and reviewed 32 articles eligible for the following criteria: (1) BLLs measured by Graphite Furnace Atomic Absorption Spectroscopy or Inductively Coupled Plasma-Mass Spectrometry; (2) strict quality control; (3) no lead pollution sources in the areas where the screened subjects live; and (4) sample size bigger than 100. We found that mean BLLs of Chinese children was 92.9 microg/L (37.2-254.2 microg/L), and 33.8% (9.6-80.5%) of the subjects had BLLs higher than 100 microg/L. Nine of the 27 provinces or cities reported had average BLLs 100 microg/L. Boys' BLL was 96.4 microg/L, significantly higher than girls' 89.4 microg/L (P<0.001). BLLs of children 6 years increased with age. The mean BLLs of children living in industrial and urban areas were significantly higher than those of children in suburbs and rural areas. Our results suggested that children's BLLs in China are higher than those of their counterparts in other countries due to its heavy lead pollution. Therefore, this is of great public health importance.     

Elevated blood lead levels of children in Guiyu, an electronic waste recycling town in China

BACKGROUND: Electronic waste (e-waste) recycling has remained primitive in Guiyu, China, and thus may contribute to the elevation of blood lead levels (BLLs) in children living in the local environment. OBJECTIVES: We compared the BLLs in children living in the e-waste recycling town of Guiyu with those living in the neighboring town of Chendian. METHODS: We observed the processing of e-waste recycling in Guiyu and studied BLLs in a cluster sample of 226 children < 6 years of age who lived in Guiyu and Chendian. BLLs were determined with atomic absorption spectrophotometry. Hemoglobin (Hgb) and physical indexes (height and weight, head and chest circumferences) were also measured. RESULTS: BLLs in 165 children of Guiyu ranged from 4.40 to 32.67 microg/dL with a mean of 15.3 microg/dL, whereas BLLs in 61 children of Chendian were from 4.09 to 23.10 microg/dL with a mean of 9.94 microg/dL. Statistical analyses showed that children living in Guiyu had significantly higher BLLs compared with those living in Chendian (p < 0.01). Of children in Guiyu, 81.8% (135 of 165) had BLLs > 10 microg/dL, compared with 37.7% of children (23 of 61) in Chendian (p < 0.01). In addition, we observed a significant increasing trend in BLLs with increasing age in Guiyu (p < 0.01). It appeared that there was correlation between the BLLs in children and numbers of e-waste workshops. However, no significant difference in Hgb level or physical indexes was found between the two towns. CONCLUSIONS: The primitive e-waste recycling activities may contribute to the elevated BLLs in children living in Guiyu.     

Lead exposure of children and newborns in Porto, Portugal

Lead is a naturally occurring element that has multipurpose applications and has been used since early civilizations being widespread in the environment. Lead is not biodegradable and its continual use has contaminated air, water, and soil. It is highly toxic affecting the whole body and is particularly harmful to newborns and children, adversely affecting cognitive development and behaviour. For children aged <6 years the Centres for Disease Control and Prevention (CDC), in 1991, defined an elevated blood lead level (BLL) as >or= 10 microg/dl, but evidence exists for subtle effects at lower levels. From the 1980s, the international trend has been to phase-out lead content in gasoline, which has contributed to substantially lower average BLLs in these populations. However, its complete elimination from gasoline in Portugal was not reached before 1999. Our group has from long participated in BLL surveillance programs to help target prevention efforts and monitor progress toward reducing BLLs in Portugal. Here are presented the studies carried out with children.     

Transition of cord blood lead level, 1985-2002, in the Taipei area and its determinants after the cease of leaded gasoline use

Lead has long been of concern for its toxicity, impairment of neurobehavioral and cognitive development, and electrophysiological deficits in children, even at levels less than 10 microg/dL. The present study was conducted to elucidate the extent of cord blood lead level decline in the Taipei area from 1985 to 2002 and to explore the factors affecting the cord blood lead level after the cease of leaded gasoline use. In the current study period of 2001-2002, 184 of 1310 newborns delivered in the Taipei Municipal Women and Children Hospital between September 2001 and August 2002 were eligible and randomly selected to participate in this study. Neither of their parents had an occupational lead exposure history. At each delivery, a sample of 5-10 mL umbilical cord blood was collected for lead determination by graphite furnace atomic absorption spectrometry. The cord blood lead level of the newborns in the current study period averaged 2.35 +/- 1.12 microg/dL. Together with the cord blood lead averages of 7.48 +/- 2.25 and 3.28 +/- 1.52 microg/dL obtained from two previous surveys conducted in 1985-1987 and 1990-1992, respectively, the cord blood lead level was significantly decreased (P < 0.005). It is estimated that such a reduction in cord blood lead from 7.48 to 2.35 microg/dL for each year's cohort of 260,000 newborns in Taiwan might benefit the economics, ranging from US$8.9 billion to US$12.1 billion by improving the worker productivity. For the time period from 1985 to 2002, there were consistent transition patterns among the yearly fluctuations of air lead level, leaded gasoline consumption, lead content in gasoline, estimated lead amount emitted from the consumed leaded gasoline, and average cord blood lead levels of the three respective study periods. Additionally, every 0.1-g/L reduction in lead content in gasoline might lead to a lowering of cord blood lead level by 1.78 microg/dL. Furthermore, at low level of around 2 microg/dL, a multiple regression analysis demonstrated that economic status was the most influential factor for cord blood lead variation (P = 0.0061) while the maternal working month during her pregnancy was retained in the model with borderline effect (P = 0.0625). After accounting for the effect of leaded gasoline on the cord blood lead level, future study to differentiate the primary contributors for the low-level cord blood lead variation around 1-2 microg/dL is warranted.     

Zinc protoporphyrin IX concentrations between normal adults and the lead-exposed workers measured by HPLC, spectrofluorometer, and hematofluorometer

To establish the relationship between Zinc protoporphyrin (ZPP) concentrations and blood lead (PbB) levels and to identify reliable analytical methods of ZPP and Protoporhyrin (PP), blood samples were obtained from 263 office workers without the history of occupational lead exposure and 49 lead-acid battery workers. The mean concentrations of PbB for the normal adults and the battery workers were 9.26 microg/dl and 42.60 microg/dl, respectively. The geometric mean concentrations of ZPP and PP by HPLC were 18.73 microg/dl and 2.27 microg/dl for normal adults and were 46.99 microg/dl and 5.53 microg/dl for the exposed workers, respectively. The geometric mean concentrations of ZPP and PP by a spectrofluorometer (SF) were 30.27 microg/dl and 5.16 microg/dl for normal adults and were 50.91 microg/dl and 6.69 +/- 1.39 microg/dl for the exposed workers. The geometric mean ZPP concentration measured by a hematofluorometer (HF) was 30.88 microg/dl for normal adults. The results showed that ZPP concentrations measured by HF were consistently higher than those by HPLC and SF for normal adults, and lower for the exposed workers. ZPP concentrations were not correlated with PbB levels for normal adults but a statistically significant correlation was found among the exposed workers.