Incorporating source apportionment and health risk assessment of heavy metals from indoor dust of an industrial area in Dhaka, Bangladesh

A total of 45 deposited dust samples were collected from the preselected 15 households near an industrial area at Savar, Bangladesh. The concentrations of metals were measured by EDXRF spectroscopy and was found at the following trend: Ca > Fe > K > Ti > Mn > Zr > Sr > Rb > Zn > Cu > Pb > Co. The average concentrations of Cu, Zn, Zr, and Pb were found to be higher than that of the soil background values set by Chinese Environmental Protection Administration (CEPA) and the upper continental crust (UCC), while the average concentrations of K, Ti, Fe, and Rb were found to be higher than that of the background values and lower than that of UCC. Alternately, %RSD for some toxic metals (i.e., Fe, Co, Zn and Pb) in the dust samples were ranged broadly (%RSD: 33.54–86.88 %), which indicates that these trace metals might be present in indoor dust samples due to anthropogenic sources, which is consistent with the ANOVA test. In this study, the contamination levels of metals were assessed based on the enrichment factor (EF), pollution load index (PLI), and geo-accumulation index (I_geo). The two ways ANOVA (F_cal = 3.86 > F_critic = 1.78, df = 14) for EF data had revealed the heterogeneity of metal enrichment in the study area, whereas PLI values were close to 1.0 or > 1, which indicated that the indoor dust samples in the study area might be deteriorated of site quality by the studied metals. The analysis of I_geo also revealed that these dust samples are slightly to extremely polluted. Conversely Pearson correlation analysis, principal component analysis, and cluster analysis were employed to identify the possible sources of such heavy metals, which suggested that the anthropogenic sources are the main sources of the examined heavy elements. Subsequently, the human health risk assessment strategies were applied to identify the routes of exposures based on the US EPA health risk models. For non-cancer effect, ingestion of dust particles is the main exposure route to both the children and adults. The total hazard index (HI) values indicate that both children and adults are vulnerable to non-carcinogenic effect, but children are more vulnerable than adults (t_stat = 1.97 > t_critic = 2.039, p = 0.029) at a 95 % confidence level. Nevertheless, no significant carcinogenic health risk due to the presence of Co was found for both children and adults in the study area. According to sensitivity analysis, the ingestion rate (IR) and the concentration of Co posed the most significant impact (> 79.9 %) on cancer risk estimation.