Background: Urban deposited dust and ambient particulate matter are important reservoirs of potentially toxic metals in arid cities where traffic, workshops, construction, and dust storms coexist. Najaf, Iraq, also experiences periodic traffic and pedestrian-pressure increases related to religious visitation.
Purpose: This study analysed Pb, Cd, and Ni in a station-month dataset from six land-use stations in Najaf between October and March, focusing on spatial gradients, monthly variation, metal co-variation, and readiness for defensible health-risk assessment.
Methods: Settled dust samples were collected monthly from six land-use stations, yielding 36 station-month observations for each metal. After wet-acid digestion, metals were determined by atomic absorption spectrometry, with graphite furnace AAS used for low-level toxic metals. Station and monthly means, fold enrichment relative to the semi-rural reference site, Pearson correlations, one-way ANOVA, Kruskal–Wallis tests, and a normalized hotspot-priority score were calculated.
Findings: S5 showed the highest mean Pb, Cd, and Ni concentrations, whereas S6 showed the lowest. Compared with S6, S5 was 2.30-, 3.93-, and 2.76-fold higher for Pb, Cd, and Ni, respectively. Station-level differences were significant for all metals, while monthly differences were weaker and non-significant. Metals were strongly correlated.
Conclusion: Metal distribution was controlled mainly by land use rather than month. Industrial-transport and pilgrimage/traffic-influenced zones require priority monitoring, while definitive HQ, HI, and ILCR modelling needs complete exposure-pathway and toxicity-parameter specification.