The correlation between the intensity of benzene exposure and complete blood count in the oil and natural gas company workers in East Kalimantan

Abstract

Benzene is one of the dangerous chemical substances which can cause some health disturbances.
Meta-analysis shows that people who are exposed to benzene have a leukemia risk of 1.4 times
more than the ones who are not. The employees who are exposed to benzene for a long time
have a probability to receive the toxic effect from benzene. This study was conducted to evaluate
the relationship between the intensity of benzene exposure and blood count of employees in the
oil and natural gas company in East Kalimantan. This research was conducted to 897 employees
with case control design. The control group consisted of 521 subjects, whereas the case group
consisted of 376 subjects. The subjects were 39.91±10.90 years old, with the working term
between 1 to 36 years. Data were obtained from routine medical check-up and health risk
assessment in 2007 – 2010. The independent variable namely benzene exposure and the dependent
variable namely result of blood count, were analyzed by using chi-square bivariat analysis.
Intensity of benzene exposure was measured as OVM (Organic Vapour Monitor) for external
dosage and SPMA (S-phenylmercapturic acid) for internal dosage. The intensity of benzene in
2007 was 1.07± 5.5 ppm (OVM) and average of SPMA was 11.54±5.28 ìg/g creatinine. The
intensity of benzene in 2009 was 4.15±13.6 ppm (OVM) and SPMA was 55.90±43.6 ìg/g
creatinine. The employees who were exposed to benzene had a risk of having a decrease of
either hemoglobin, erythrocyte, thrombocyte, or leukocyte 1.71 times (95% CI, 1.18–2.48)
compared with the control, although this reduction was still in the normal range (p= 0.004). In
conclusion, there was no relationship between the intensity of benzene exposure with the low
blood count of the employees.

Keywords: benzene exposure - complete blood counts - oil and gas earth - mining - toxic effect