Determinants of blood and saliva lead concentrations in adult gardeners on urban agricultural sites

Bramwell, Lindsay, Morton, Jackie, Harding, Anne-Helen, Lin, Nan and Entwistle, Jane (2021) Determinants of blood and saliva lead concentrations in adult gardeners on urban agricultural sites. Environmental Geochemistry and Health. ISSN 0269-4042 (In Press)

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Soil Pb concentrations at urban agriculture sites (UAS) commonly exceed recommended safe levels. There is a lack of evidence regarding uptake of Pb by gardeners using such sites for food crops. Our study aimed to elucidate whether gardening in soil with raised Pb levels results in Pb body burdens of concern to health, and to assess confounding factors influencing Pb body burden. Our cross-sectional case study measured Pb in saliva and blood of UAS gardeners (n = 43), soil and produce samples from their UAS, and home tap water. Blood and saliva Pb concentrations were compared with those from non-UAS gardener controls (n = 29). A health risk threshold of 5 µg dL−1 blood Pb level (BLL) was selected in keeping with international guidance. Detailed surveys investigated individuals’ anthropometrics and potential Pb exposures from diet, and historic and everyday activities. Saliva was not found to be a suitable biomarker of adult Pb exposure in this context. Predictors of higher BLLs were being older, being male and eating more root vegetables and shrub fruit. Eating more green vegetables predicted a lower BLL, suggesting a protective effect against Pb uptake. UAS gardeners’ BLLs (geometric mean 1.53; range 0.6–4.1 µg dL−1) were not significantly higher (p = 0.39) than the control group (geometric mean 1.43; range 0.7–2.9 µg dL−1). All BLLs were below 5 µg dL−1 except one resulting from occupational exposure. Having paired the UAS gardeners with closely matched controls, we found Pb in UAS soils (with range 62–1300 mg kg−1from common urban sources) unlikely to pose an additional risk to adult health compared to their neighbours who did not access UAS. As such, other Pb sources may be the dominant factor controlling BLL.

Item Type: Article
Additional Information: Funding information: This study was partially funded by the Institutes for Sustainability and Social Renewal, Newcastle University, Newcastle City Council, the Society of Brownfield Risk Assessment (SoBRA) and Northumbria University. In addition laboratory analysis as in-kind support was provided by the Health and Safety Executive, Northumbria Water Limited, (thanks to Mark Weatheritt), and ALS Global (many thanks to Geraint Williams and Ilia Rodushkin).
Uncontrolled Keywords: Human biomonitoring, Blood lead, Saliva lead, Urban agriculture, Exposure assessment, Allotments
Subjects: F400 Forensic and Archaeological Science
L700 Human and Social Geography
Department: Faculties > Engineering and Environment > Geography and Environmental Sciences
Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User: John Coen
Date Deposited: 16 Sep 2021 10:17
Last Modified: 21 Oct 2021 16:15

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