ENVIRONMENTAL CONCENTRATION OF CARBONYL COMPOUNDS AND BTEX IN RESIDENTIAL AREAS OF INNER CITY OF BANGKOK AND THEIR POSSIBLE HEALTH RISK

Abstract

This study aimed to determine the concentrations of carbonyl compounds and BTEX in indoor and outdoor environments and estimate the potential health risk of the residents via inhalation exposure. All samples were taken from 5 communities during dry season (21st April to 24th May, 2013) and wet season (22nd September to 25th October, 2013) by using 2, 4 dinitrophenylhydrazine (DNPH) cartridge and charcoal glass tube connected with personal air pump with air flow rate equaled 100 mL/min for carbonyl compounds and BTEX collections, respectively. The equipments were installed at indoor and outdoor environments at 1.5-2.0 meter height above the ground during 24 hours. Carbonyl compounds extracted by using acetonitrile and BTEX extracted by using carbon disulfide were analyzed by using HPLC/UV and GC/FID, respectively. The results shew the indoor concentrations of four main carbonyl compounds which were formaldehyde, acetaldehyde, propionaldehye, and hexanaldehyde were ranked in 0.14-38.73, 0.10-11.02, 0.03-2.08, and 0.03-6.28 µg/m3, respectively. And benzene, toluene, m-,p-xylene, and o-xlyene were ranked in According to lifetime cancer risk from indoor concentrations based on general scenario, the results revealed that 95% CI of formaldehyde, acetaldehyde, benzene, and ethylbenzene were in the ranges of 5.99x10-5-4.72x10-5, 1.09x10-5-9.93x10-6, 1.03x10-4-8.83x10-5, and 1.45x10-5-1.10x10-5µg/m3, respectively. In case of age interval scenario, the 95% CI of lifetime cancer risk of these chemicals were in the ranges of 1.94x10-4-1.79x10-4, 3.20x10-5-3.00x10-5, 2.72x10-3-2.40x10-3, and 5.78x10-5-5.38x10-5. Most cancer risk from both scenarios were above the acceptable criteria which one people from one million people had possibility of developing cancer (or 10-6). There were some overestimated risk due to exposure during equaled to 24 hours and the exposure frequency equaled to 350 days/year, while the most non-cancer risks were in the acceptable range.