Health Risk Assessment of Indoor Dust-associated Heavy Metals Obtained from Four Philippine Public Hospitals

Abstract

Background and Objectives: Heavy metal concentrations in indoor dusts can have significant human health risks through inhalation, ingestion, and dermal absorption. The study aimed to assess the health risks of four heavy metal concentrations (Pb, Cd, Hg, and As) obtained in indoor dust from selected public hospitals situated along populous cities in Metro Manila and Batangas province.

Methodology: Samples of air-con dust were collected from four hospitals: two in Metro Manila and two in the province of Batangas. Flame atomic absorption (FLAA) was utilized for the determination of Pb and Cd, hydridegeneration atomic absorption spectroscopy (HG-AAS) for As, and cold vapor atomic absorption (CVAA) for Hg. Public hospitals were anonymized and coded with M1, M2, B1, and B2 for ethical reasons. Non-carcinogenic risks were inferred by calculating the hazard quotients (HQ) and hazard indices (HI) of the heavy metals, while carcinogenic risks were stipulated by obtaining their cancer risk values.

Results: Results showed that one hospital in Manila (M2) possessed 1.44 mgkg⁻¹ Pb, 0.02 mgkg⁻¹ Cd, 0.74 mgkg⁻¹ Hg, and 2.00 mgkg⁻¹ As; while the other one (M1) registered indoor dust of 0.53 mgkg⁻¹ Pb, 0.48 mgkg⁻¹ Hg, and 1.80 mgkg⁻¹ As. One hospital in Batangas (B1) had 0.23 mgkg⁻¹ Pb, 0.35 mgkg⁻¹ Hg, and 2.50 mgkg⁻¹ As; while the other one (B2) generated 0.15 mgkg⁻¹ Pb, 0.19 mgkg⁻¹ Hg, and 1.50 mgkg⁻¹ As. These concentrations all yielded HQ<1 and HI<1, indications of their insufficiency to induce significant non-carcinogenic health detriments. Analysis on the carcinogenic heavy metals, Cd and As, showed cancer values on the lower limit of the carcinogenicity threshold, 1x10⁻⁶ -1x10⁻⁴.

Conclusion: As to date, all of HQ, HI, and cancer risk values are lower than the threshold limits, indicating that the observed concentrations of heavy metals are within safe levels. However, additional caution is still advised for people who are susceptible to health risks associated with long-term exposure to heavy metals.