Heavy metal(loid)s (HMs) in soils of Southwest China naturally have a high background and are superimposed with intensive anthropogenic activities, resulting in serious accumulation of HMs in regional agricultural soils, which poses threat to ecological security and agricultural product quality. The accumulation and source apportionment of HMs in agricultural soils are not only one of the focuses of global concern but also a challenging task worldwide. In the present study, a total of 395 topsoil samples (0-20 cm) and 19 deep soil samples (150-180 cm) were collected from typical artisanal zinc smelting regions in northwestern Guizhou Province, China to investigate the spatial distribution, accumulation and source apportionment of HMs (As, Cr, Cu, Hg, Ni, Pb, Cd and Zn) based on the combined approach of enrichment factor (EF), self-organizing map (SOM), geographical information system (GIS), and positive matrix factorization (PMF). The mean contents of As, Cr, Cu, Hg, Ni, Pb, Cd and Zn in agricultural soils all exceeded the corresponding local background values, and obvious enrichment of Cd was found in the studied topsoil, followed by Pb, Cu, and Zn. Combined with SOM and PMF analysis, five potential HMs sources were identified: Cd (74.58%), As (32.05%), Zn (30.57%), Hg (23.16%), and Pb (11.38%) were associated with artisanal Zn smelting activities; Cu (66.08%), Zn (18.12%), Ni (17.25%), Cd (16.95%), and Pb (10.08%) were mainly from agricultural activities; Pb (68.9%), Zn (25.73%), and As (22.64%) were mainly from traffic emissions and smelting-related activity sources; Hg (68.55%), As (45.31%), Cr (38.63%), and Ni (32.44%) were primarily from atmospheric deposition associated with industrial activities and coal combustion; and Cr (61.01%), Ni (44.52%), Zn (17.32%), Cu (16.11%), and Cd (8.39%) mainly originated from soil parent materials. The proportions of the five potential sources were 14.5%, 20.9%, 19.8%, 17.8%, and 27%, respectively. Anthropogenic sources accounted for the largest contribution (approximately 73%) to the soil HMs, especially the artisanal zinc smelting activities to Cd, Zn, As, Hg, and Pb, which was significantly higher than that of geological sources, suggesting that intense human activities produced a large amount of HMs enrichment in topsoil. The SOM clustering and source apportionment of soil HMs are of great significance for reducing HMs pollution sources, and can provide scientific guidance for pollution prevention and regional remediation of HMs in agricultural soils. [ABSTRACT FROM AUTHOR]