Twenty-six tons of lead oxide used per year in wooden boat building and repairing in southern Thailand

In southern Thailand, the wooden boat building and repair industry uses powdered lead oxide (Pb₃O_4, or red lead) in the caulking process. This had been shown to be a significant source of contamination in the workplace and the communities. This cross-sectional study was conducted to estimate the amount of lead oxide used in the region and to document the management of hazardous waste product in this industry. All boatyards in southern Thailand registered to the Ministry of Industry were visited with walk-through observation. After consent, questionnaire-based interviews were conducted among workers and boatyard owners who rented out the space for building and repairing the boats. Of the 63 active boatyards identified, approximately 26 tons of lead oxide was used to repair approximately 8,000 boats each year. Due to the casual employment system in this industry, no facility for the protection of workers and the environment from lead contamination exists. The findings indicate the need for further studies on the extent of contamination in the broader area. Intervention programmes are also urgently needed to reduce the release of this hazardous waste into the community.     

Development and field trial of a household surface lead loading rate sampling device in a lead-contaminated community of southern Thailand

A new dust-collecting device was developed to assess surface lead loading rates in houses in communities contaminated with lead oxide dust used for caulking in nearby boat-repair yards. The device consists of two small glass sheets with total area of 1,200 cm² placed in two plastic trays suspended from the ceiling in the house for 3 months before wiping and sending the dust specimen for determination of lead content using flame atomic absorption spectrophotometry. After a pilot trial in four households, further data were collected from 43 matched pairs of boat-caulkers’ and neighboring control households. All devices were retained in the house for 3 months without any complaint. Static measurements of lead dust levels were also assessed in all households. The values significantly discriminated high from low lead exposure households (p = 0.015) and provided good correlations with floor lead loading (Spearman rank correlation coefficient, r = 0.39 to 0.62) and dust lead content (r = 0.53 to 0.64). This sampling method is an alternative to others which consume more household space or require a longer collection period.