Tanasorn Tunsaringkarn

Organophosphate Pesticide Exposure in School-Aged Children Living in Rice and Aquacultural Farming Regions of Thailand

ABSTRACT Organophosphate pesticides (OPs) are widely used in agricultural sectors in Thailand. Previous studies have documented that children residing in agricultural areas have higher exposure to OPs than children living in other residential areas. The objective of this study was to quantify urinary biomarkers of OP exposure and determine the environmental conditions and activities that predict their levels among children living in Central Thailand farming regions. In October 2011, 53 6–8-year-old participants were recruited from Pathum Thani Province, Thailand. Twenty-four lived in rice farming communities at Khlong Luang District where OPs are the pesticides used frequently. Twenty-nine participants, living in aquacultural farming communities at Lum Luk Ka District where OPs are not used, were recruited to serve as controls for pathways of exposure (e.g., residential, dietary) other than occupational/paraoccupational exposures encountered in rice farming. Household environments and participants’ activities were assessed using a parental structured interview. Urine samples (first morning voids) were collected from participants for OP urinary metabolite (i.e., dialkylphosphates [DAPs] and 3,5,6-trichloro-2-pyridinol [TCPy]) measurements. The levels of most urinary OP metabolites were significantly higher in participants who lived in a rice farming community than those who lived in an aquacultural farming community (P < .05). The results from linear regression analysis revealed that the frequency of OP application on rice farms (∑DAP: P = .001; TCPy: P = .001) and living in a rice farming community (∑DAP: P = .009; TCPy: P < .001) were significant predictors of urinary DAP metabolite levels in participants. Increasing TCPy levels were significantly related to proximity to rice farm (P = .03), being with parent while working on a farm (P = .02), playing on a farm (P = .03), and the presence of observable dirt accumulated on the child’s body (P = .02). In conclusion, OP metabolite levels among children who live in rice farming communities were strongly influenced by farming activity, household environments, and child behaviors, suggesting that these are the primary pathways in which children living in these agricultural communities in Thailand were exposed to OPs.

Health Risk Assessment of Petrol Station Workers in the Inner City of Bangkok, Thailand, to the Exposure to BTEX and Carbonyl Compounds by Inhalation

ABSTRACT The occupational health risk of petrol station workers from exposure to BTEX and carbonyl compounds via inhalation was estimated in the inner city of Bangkok. Personal sampling was performed within the workers’ breathing zone using 2,4 dinitrophenylhydrazine cartridges and charcoal glass tubes connected to a personal air pump during eight working hours at six petrol stations. BTEX and carbonyl compounds were quantitatively analyzed by GC/FID and HPLC/UV, respectively. Of all detectable BTEX and carbonyl compounds, the levels of the four most prevalent compounds (benzene, ethylbenzene, formaldehyde, and acetaldehyde) were used to assess the lifetime cancer risk and 95% confidence interval of the risk levels were found to be totally higher than acceptable criteria for benzene (1.82 × 10–4–2.50 × 10–4), formaldehyde (7.81 × 10–6–1.04 × 10–5), ethylbenzene (4.11 × 10–6–5.52 × 10–6), and acetaldehyde (1.39 × 10–6–2.45 × 10–6). Thus, petrol station workers in the inner city of Bangkok have a potentially high cancer risk through inhalation exposure. With respect to the noncarcinogenic agents, toluene, m,p-xylene, o-xylene, and propionaldehyde, all non-cancer health risk were within hazard quotients of 1 and of acceptable risk.

Cancer risk analysis of benzene, formaldehyde and acetaldehyde on gasoline station workers

Background: Benzene, formaldehyde and acetaldehyde are carcinogenic substances to which gasoline station workers are most likely exposed via inhalation. To evaluate these compounds in the ambient air of gasoline stations, the inhalation exposure test on workers was performed and assessed. By the appropriate intervention of wearing mask and hand washing during work shift, we determined whether or not there is cancer risk to the exposure of benzene, formaldehyde and acetaldehyde using urinary biomarkers. Methods: A cross sectional study was conducted in 38 workers of 6 gasoline stations in Pathumwan District, Bangkok, Thailand. Inhalation and ambient air concentrations of benzene, formaldehyde and acetaldehyde were evaluated by GC/FID and HPLC/UV detectors. Urinary trans, trans-muconic acid (t,t-MA), formaldehyde and acetaldehyde concentrations detected in gasoline workers before and after appropriate intervention were analyzed by GC/FID. Results: The average inhalation exposure concentrations of benzene, formaldehyde and acetaldehyde were 195.56, 12.60 and 5.74 µg/m3, respectively. The level of benzene exposure was significantly higher than the ambient air level (independent t-test, p < 0.01). The average lifetime cancer risk of the workers exposed to benzene, formaldehyde and acetaldehyde was determined at the values of 2.15E-04, 1.27E-05 and 2.69E-06, respectively. Benzene and formaldehyde values were higher than an acceptable criteria defined as 1E-06. The amount of urinary t,t-MA, formaldehyde and acetaldehyde in the workers daily after 7-days appropriate intervention (wearing masks as personal protective equipment (PPE) and hand washing) was decreased. Formaldehyde and acetaldehyde, which were detected in urine, showed significantly lower than before intervention (pair t-test, p < 0.001). Conclusions: Results from our study confirmed that the gasoline workers have high chances of cancer risk from daily exposure to benzene and formaldehyde. The urinary’s t,t-MA, formaldehyde and acetaldehyde could be considerably used as biomarkers in gasoline station workers. An appropriate intervention, using PPE and hand washing, could reduce the cancer risk.

Inhibitory activity of Heinz body induction in vitro antioxidant model and tannin concentration of Thai mimosaceous plant extracts

Medicinal plants have been used for traditional treatment and known to possess antioxidant activities that may help to reduce the risk of oxidative stress-related diseases. Chemically-induced oxidative hemolysis is usually associated with the formation of Heinz bodies-insoluble precipitates within red blood cells, indicating the oxidative destruction of hemoglobin. In the present study, antioxidant activity was investigated by Heinz body induction