Risk assessment of multi-route exposure to organophosphate pesticide of vegetable growers : A case study at Bang Rieng sub-district, Khuan Nieng district, Songkhla province

This study investigated the multi-route exposure of organophosphate pesticides (OPPs) and evaluated health risk to vegetable growers living in the Bang Rieng agricultural community. Samples were collected in wet- and dry- season, then the residues of organophosphate pesticides i.e. chlorpyrifos, dicrotofos and profenofos contaminated in water, soil, air, and on the vegetable growers contact area i.e. hand and their bodies were analyzed. OPPs metabolite residues were also quantified from urine samples collected from 33 vegetable growers and 17 reference people living outside farm. The results showed that OPPs mean concentrations in water, air, soil, vegetable grower’s hands and their bodies were in the range of 0.011-0.217 µg/L, 0.024-0.070 mg/m3, 0.004-0.881 mg/kg, 0.024-0.086 mg/two hands, 0.588-2.112 µg/cm2, respectively. Besides, the average concentration of urinary OPPs metabolite in the vegetable growers was significantly higher than the reference in both seasons. The results indicated that the occupational exposure pathways of the vegetable growers were (1) water ingestion, (2) air inhalation, (3) dermal contact of OPPs by hand and body directly and OPPs residues in water and soil. Long-term exposure of these non-carcinogenic pesticides in the vegetable growers may result in chronic adverse health effect in which the Hazard Index (HI) of the exposure pathways for inhalation, hand contact, and body contact were greater than acceptable level (HI >1). The HI of the pathways in the dry season were 38, 6, and 88 times, respectively and 36, 11, and 62 times, respectively in the wet season. Water use for the vegetable growers, i.e., drinking and bathing, and soil contact may not be at risk. For acute adverse effects, the vegetable growers may be at risk via the inhalation pathway of chlorpyrifos and dicrotofos during their applications through pesticide mixing, loading, and spraying. The dicrotofos with the highest risk estimation (highest HI) is the most dangerous pesticides. This study suggested that the authorities and community should have the appropriate strategies concerning about risk reduction and risk management.