摘要：Objectives. We aimed to (1) evaluate the relation between home age and concentrations of multiple chemical contaminants in settled dust and (2) discuss the feasibility of using lead hazard controls to reduce children’s exposure to persistent organic pollutants. Methods. As part of the California Childhood Leukemia Study, from 2001 to 2007, we used a high-volume small surface sampler and household vacuum cleaners to collect dust samples from 583 homes and analyzed the samples for 94 chemicals with gas chromatography–mass spectrometry and inductively coupled plasma mass spectrometry. We evaluated relations between chemical concentrations in dust and home age with Spearman rank correlation coefficients. Results. Dust concentrations of lead, polychlorinated biphenyls, organochlorine insecticides, and polycyclic aromatic hydrocarbons were correlated with home age (ρ > 0.2; P < .001), whereas concentrations of pyrethroid insecticides and polybrominated diphenyl ethers were not. Conclusions. Dust in older homes contains higher levels of multiple, persistent chemicals than does dust in newer homes. Further development of strategies to reduce chemical exposures for children living in older homes is warranted. Settled dust found indoors is a mixture of biologically derived materials, particles deposited from indoor aerosols, particles deposited from building materials (e.g., deteriorated paint), and soil particles that infiltrate from outdoors (e.g., soil tracked indoors on shoes). 1 Because typical cleaning removes only a portion of dust from indoor environments (e.g., when vacuuming a carpet), indoor dust acts as a reservoir for chemical contamination. 2 Settled dust can be an important source of chemical exposures, especially for young children, who have frequent hand-to-mouth contact. 3 As early as 1904, Gibson suggested the importance of dust as a route of exposure to lead, hypothesizing that “painted surfaces . . . become a dry easily detachable powder . . . carried to the mouths of children . . . who bite their nails, suck their fingers or eat with unwashed hands.” 4 (p302) More than a century after dust was first implicated in childhood lead poisoning, children’s exposure to lead-contaminated dust remains a major public health issue, especially for children living in older homes. 5,6 Lead-based paint, the major source of lead in the residential environment, 7 was banned in the United States in 1978. Thus, homes that predate the ban are more likely to contain lead-based paint, and these older homes have greater lead contamination than do newer homes. 8 Numerous investigators have reported a relation between home age and lead levels in dust (Table A, available as a supplement to the online version of this article at http://www.ajph.org ). In addition to lead, several organic chemicals that were used extensively worldwide have been banned, including polychlorinated biphenyls (PCBs) and organochlorine insecticides; and these contaminants likewise have been found at higher levels in dust from older homes compared with newer homes (Table B, available as a supplement to the online version of this article at http://www.ajph.org ). As part of the California Childhood Leukemia Study (CCLS), we collected dust samples from 583 homes. We showed in previous multivariable models that home age was positively associated with levels of PCBs, 9 polycyclic aromatic hydrocarbons (PAHs), 10,11 and the organochlorine insecticides chlordane and dichlorodiphenyltrichloroethane (DDT) 12 in dust samples from CCLS homes. We present the first systematic evaluation of the relation between home age and concentrations of a broad suite of chemical contaminants in dust samples from CCLS homes. Because no established protocol exists to control persistent organic pollutants in homes, we describe mitigation strategies that have been used successfully for lead hazard control and discuss their potential utility in reducing children’s exposure to organic chemicals.
