Assessment of heavy metals in urban road dust of a city in a border province concerning their levels, sources and related health risks

Most research studies regarding the contamination of urban road dust (RD) focused on mega cities, but little consideration is
given for small cities in border areas. The present work investigated the trace elements content in 16 RD samples of particle
size < 63 μm at six areas with different anthropogenic activities in Sakaka city, KSA. The trace elements were analyzed using
XRF and ICP-MS. Significantly high trace elements concentrations were recorded at small-scale industrial area. Concentra
tions of trace elements are ranked as Fe > Mn > Pb > Zn > Cr > Cu > Co > As > Se. The contamination evaluation through
enrichment factor calculation refers to the existence of an anthropogenic source for certain trace elements, such as Fe, Zn,
Mn, Cu, and Pb. The values of contamination factor indicate the contamination of RD samples collected from small-scale
industrial area with these trace elements. The highest pollution load index value recorded at this industrial area suggests that
it is a highly polluted area. This was confirmed by applying the one-way ANOVA test for the difference analysis between the
investigated areas. The correlation between most of the detected trace elements at the small scale-industrial area was lost due
to the variation in their industrial sources. The health risk of some detected trace elements was estimated for two groups of
populations, namely workers at the small scale-industrial area and residents (adults and children) at residential areas at this
city under study. Workers and resident children were more likely affected by arsenic through the ingestion pathway to cancer
because of its higher cancer risk values that were more than the acceptable value 1 × 10−6. Workers and residents (adults and
children) are susceptible to noncarcinogenic risks through the ingestion pathway of Fe because of its higher hazard quotient
values that are more than one.