THE RELATIONSHIP BETWEEN SURFACE DUST LEAD LOADINGS ON CARPETS AND THE BLOOD LEAD OF YOUNG-CHILDREN

The final clean-up of residential lead abatement projects in federally -supported housing, as well as in other housing in a number of states, must meet surface dust lead clearance levels expressed as mu g of lea d per square foot. These clearance levels were established because han d-to-mouth ingestion of lead-contaminated dust is recognised as a majo r pathway through which many children are exposed. A dilemma exists be cause many floors in housing undergoing abatement are carpeted and the established clearance levels are generally not recommended for use on carpets. These clearance levels are also used as 'action levels' to d etermine whether exposure reduction activities are needed. The US Envi ronmental Protection Agency is currently in the process of issuing sta ndards for hazardous levels of lead in interior dust and bare soil und er Title X of the Housing and Community Development Act of 1992, 'The Residential Lead-Based Paint Hazard Reduction Act of 1992'. An effort to develop a potential surface dust lead clearance level for carpets w as made using an existing vacuum dust collection method that has previ ously been shown to be a reliable indicator of childhood lead exposure . This method was designed for use on carpeted and non-carpeted surfac es. Using data from the Cincinnati Soil Lead Abatement Demonstration P roject, the suggested floor-dust lead level where an estimated 95% of the population of children would be expected to have blood lead values below the national goal of 10 mu g dL(-1), was more than an order of magnitude lower than the current floor-dust lead clearance level of 10 80 mu g m(-2) (100 mu g ft(-2)). Further comparisons of blood lead and carpet lead levels in other parts of the country should be performed before a risk-based lead loading clearance level is established.