Urbanization alters soil trace metal enrichment and health risks in the black soil Region of Northeast China

Urban Farm DB summary

In the urban-agricultural transition zone of Arongqi in China's black soil region, researchers analyzed 32 topsoil samples (0-20 cm) from three subzones — urbanizing zone, peri-urban arable land, and urban zone — for 16 trace metals including Cd, Pb, Zn, As, Hg and Cr, plus soil organic matter. Urbanization did not worsen soil acidification but significantly reduced organic matter, and Cd, Pb, Zn, Ba, Co, Mo, Sr, V and Ag were significantly enriched above background levels, with peri-urban arable land contaminated by Cd, Mo, Sr, V and Ag and the urban zone by Cd, Pb, Ba and Sr. Carcinogenic risk was higher for adults in peri-urban arable land and for children in the urban zone, with oral ingestion and dermal contact as the dominant exposure pathways and Cr and As as the main carcinogenic factors for children; source apportionment attributed the contamination to traffic emissions (27.46%), soil parent material (24.77%), contemporary agriculture (24.54%), urban combustion (11.22%) and historical agriculture (11.22%).