A comparative cross-sectional study was conducted to determine tollbooth carbon monoxide (CO) levels and carboxyhaemoglobin (COHb) levels among the tollbooth operators and office workers in the Klang Valley, Kuala Lumpur. All tollbooths were equipped with well functioning air-conditioning. The total number of respondents was 180: 90 toll operators and 90 office workers aged between 19 and 52 years. The highest peak of CO level recorded was 61 ppm. The highest average peak CO level within a shift was 30 ppm. The CO level was higher during peak traffic at 6.00 - 8.00 a.m. There was no significant correlation between average peak CO level with vehicle load (r = -0.007, p = 0.474). The toll operators' median COHb level (1.0%, IQR = 0.8%) was significantly higher (p = 0.008) compared to office workers (0.7%, IQR = 0.8). There was a weak and significant correlation between COHb levels with average peak CO levels (r = 0.228, p = 0.031). In conclusion, tollbooth operators were chronically exposed to CO leading to higher COHb levels compared to office workers.
Introduction: A study on biological monitoring of lead on children was conducted when unleaded gasoline was widely used in 1998. The objectives were to monitor lead exposure using blood lead, urine d-aminolevulinic acid (d-ALA) and urine lead concentrations as biological indicators and to determine the relationship between these variables.
Methodology: Two hundred and sixty-nine school children, 169 from an urban school of Kuala Lumpur and 100 from an industrial school in southern Malaysia were selected for the study. These were Malay children in the age range of 61/2 to 81/2 years old. Blood and urine lead concentrations were analyzed using the Graphite Furnace Atomic Absorption Spectrophotometer. Urine d-ALA was measured with Spectrophotometer UV/VIS.
Results: The mean blood lead concentrations of the urban children (3.56 mg/dl) and the industrial children (3.75 mg/dl) were not significantly different (p=0.451). The urine d-ALA (urban=9.606; industrial=6.965 mg/g creatinine) and urine lead (urban=2.625; industrial=4.548 mg/g creatinine) of the urban children were significantly higher than the industrial children (p=0.014: p 10 mg/dl. About 78% of the urban children and 76% of the industrial children have urine d-ALA in a normal range (<0.6 mg/100ml) while 22% of the urban children and 24% of the industrial children were in the acceptable range (0.6 - 2.0 mg/100ml). All the children had normal urine lead concentrations (<8 mg/100ml).
Conclusion: These children were not highly exposed to lead as indicated by their blood lead, urine d-ALA and urine lead concentrations which were below the allowable standard in both study areas . This may be due to the total ban on leaded gasoline in the country since 1998 and as a result, the environmental lead exposure in these areas was quite low.
Keywords: Children's lead exposure, blood lead, urine lead, urine d-ALA
This study aimed to determine the relationship between blood lead (BPb) concentrations and cognitive and physical development in school children. A total of 169 urban children and 100 industrial children of Malay ethnicity, in the age range of 6(1/2) to 8(1/2) years, were selected. BPb was determined using GF atomic absorption spectrophotometer. The mean cognitive score (102.55) of the children from the industrial area was significantly higher than that of the urban children (95.09; P < .001). However, no significant differences were found in the BPb levels between the 2 groups (industrial, 3.75 microg/dL; urban, 3.56 microg/dL). There was significant inverse correlation between BPb and cognitive scores for all children (P < .05). The cognitive scores for all children were influenced by BPb after adjustments (P < .05). The urban children had significantly better Weight for Height and Left Arm Circumference values than those from industrial area. There was no significant correlation between BPb and the anthropometric measurements. In conclusion, low BPb influenced the cognitive development, whereas physical development was not affected.