Redecoration of external leaded paintwork and lead-in-dust concentrations in school playgrounds.

Playground lead-in-dust concentrations have been measured immediately after the external redecoration of 216 schools in 1983/4 and of 63 schools in 1984/5. Schools were divided into four age categories: A, pre-1914; B, 1914-1939; C, 1945-1965; and D, post-1965. The results show that concentrations can vary widely from school to school within a given age category. For each school, dust samples were collected from an area adjacent to the facade which had been redecorated, referred to here as the 'corridor' area, and from the 'remaining' playground area. The highest mean corridor concentrations were found in playgrounds of schools of age categories A and B, the highest mean value being 74,400 micrograms g-1. The highest value for age category D schools was 2600 micrograms g-1. The mean concentration for all schools in age categories A to D, was respectively 4720, 2820, 820 and 630 micrograms g-1 for the corridor area and 1180, 730, 400 and 440 micrograms g-1 for the remaining area. The highest lead-in-dust concentrations tended to occur within 2.5 m of the building facade. A limited number of measurements showed that concentrations in the corridor area tended to reduce with time, falling to half their initial value (after correcting for the local background level) in about 90-170 days. A model is suggested linking lead-in-dust concentrations in the corridor and remaining areas to lead-in-paint debris dust concentrations.