The effectiveness of a home cleaning intervention strategy in reducing potential dust and lead exposures

The changes in dust loading, lead loading and lead concentration, determined from vacuum samples and wipe samples collected during the Childhood Lead Exposure Assessment and Reduction Study (CLEARS) were analyzed to determine the efficacy of the cleaning protocol in homes of children found to have moderate lead poisoning, e.g. levels between 10-20 micrograms/dL. The samples were collected at least twice, and in 65 homes three times, during the course of a year long intervention in homes where half were randomized into a group which received a standardized Lead Intervention program for lead reduction, and the other homes only received an Accident Intervention program. The homes with lead burdened children were located in Hudson County, New Jersey (primarily in Jersey City), and were referred to the CLEARS by a number of private and public sources. Each home had wipe sampling conducted with the LWW Sampler (patented), and vacuum sampling was completed using a device described by Wang et al. in Applied Occupational and Environmental Hygiene. The results were compared in two ways: (1) between the two intervention groups, and (2) over the time course of the intervention period. When compared to the values seen in the first visit vacuum sampling results showed statistically significant decreases in lead loading and dust loading by the third sampling visit for the Lead Intervention homes. Substantial reductions in lead loading and dust loading were also seen when the Lead Intervention values were compared to values obtained in the Accident Intervention homes over the course of the year long intervention. The wipe sampling results for the 65 homes with three visits found no significant reductions in dust loading and lead loading among any of the room surfaces sampled in the Accident Intervention homes. There were 75% and 50% reductions observed on the window sills and on the bedroom floors of the homes which participated in the Lead Intervention. The levels in the living room and the kitchen showed very little change in loadings. This appeared to be due to the fact these rooms were near a background or baseline value of 0.3 g/cm2 and 0.12 mg/cm2 for dust loading and lead, respectively. This was substantiated by the window sills and bedroom wipe sampling results since each surface approached these values by the third visit. Significant reductions in lead concentrations found in the wipe samples from the intervention homes appeared to be related to the absence of historically active sources of lead in these homes, rather than elimination of current sources. The results of the micro-environmental sampling program in CLEARS indicated that a year long cleaning protocol can significantly decrease lead levels in rugs and on other exposed surfaces. This will reduce the potential for exposure to lead among the occupants, especially children, that come in contact with such surfaces.