Soil heavy metal pollution and the prevalence of resistance genes have been a global concern, and thus many studies have reported the content of heavy metals and resistance genes in soils; however, the contents of heavy metals and antibiotic resistance genes (ARGs) in the soil in highland areas is still unclear. In this study, the environmental residues and distribution of heavy metals and resistance genes in the soil in Qinghai were analyzed, and the relationship between the concentration of heavy metals and antibiotic resistance genes in the soil was explored. Among the soil samples, the content of heavy metal zinc was the highest ［mean: (50.27±19.88) mg·kg-1］, followed by the content of heavy metal cadmium ［mean: (30.27±9.45) mg·kg-1］, and the content of heavy metal mercury was the lowest ［mean: (0.027±0.019) mg·kg-1］. The subtypes of heavy metal resistance genes in soils were mainly czcA, merA, and merP, whose main function was to be responsible for developing mercury resistance. The relative abundance of β-lactamase resistance genes (0.1505) was the highest in soil, accounting for 47.54% of the total abundance of ARGs; tetracycline resistance genes accounted for 16.93% of the total abundance of ARGs, FCA accounted for approximately 14.56%, and MLSB accounted for approximately 8.77%. The diversity and relative abundance of movable genetic elements (MGEs) were low, and only the [STBX]tnpA01[STBZ] gene was detected; intl[STBX]1[STBZ] and intl[STBX]2[STBZ] were not detected. Correlation studies showed that Cu content (r=-0.533, P=0.006) and Hg (r=0.692, P=0.006) in soil were significantly negatively correlated with altitude, whereas other heavy metals were not significantly correlated with altitude. In addition, heavy metal content was significantly correlated with soil type (P<0.05). There was a significant positive correlation between heavy metal mercury content in soils and czcA (r=0.692, P=0.006), merA (r=0.816, P=0.007), and merP (r=0.594, P=0.02). The results of this study elucidated the occurrence and distribution of heavy metals and ARGs in the Tibetan Plateau region and found that the content of heavy metals in the soil was significantly related to resistance genes.
Keywords: altitude; antibiotic resistance genes (ARGs); antibiotics; heavy metals; movable genetic elements (MGEs); soil pollution.