## 3 Results and Discussion
### Regulatory Strategies Involved in the Transmission of ARGs  
This study demonstrated that a substantial number of ARGs are enriched following the application of Imvite, MgO-Ca(H\({}_{2}\)PO\({}_{4}\))\({}_{2}\), and Imvite-MgO-Ca(H\({}_{2}\)PO\({}_{4}\))\({}_{2}\) remediation strategies. The microbial community structure in Pb contaminated soil changed significantly when treated with a composite agent and BES, reducing the relative abundance of certain ARGs. The remediation of Pb contaminated soil using MgO-Ca(H\({}_{2}\)PO\({}_{4}\))\({}_{2}\) or Imvite-MgO-Ca(H\({}_{2}\)PO\({}_{4}\))\({}_{2}\) significantly increased the total abundance of aminoglycos, \(\beta\)-lactam, multidrug, MLSB, and sulfonamide ARGs. When composite amendments combined with BES were applied for soil remediation under different initial conditions, BES-Invite-MgO-Ca(H\({}_{2}\)PO\({}_{4}\))\({}_{2}\) reduced the abundance of \(\beta\)-lactam resistance genes. Further investigation into the effects of Pb ions and pH on the performance of combined remediation agents and BES revealed that BES5-Invite-MgO-Ca(H\({}_{2}\)PO\({}_{4}\))\({}_{2}\) was more sensitive to Pb concentration, while BES10-Imvite-MgO-Ca(H\({}_{2}\)PO\({}_{4}\))\({}_{2}\) markedly increased the total abundance of \(\beta\)-lactam ARGs, although it showed an overall decreasing trend. Additionally, all remediation strategies involving MgO-Ca(H\({}_{2}\)PO\({}_{4}\))\({}_{2}\) resulted in pH elevation, but BES-Invite-MgO-Ca(H\({}_{2}\)PO\({}_{4}\))\({}_{2}\) reduced Pb ion concentrations (compared to Imvite, MgO-Ca(H\({}_{2}\)PO\({}_{4}\))\({}_{2}\), and Imvite-MgO-Ca(H\({}_{2}\)PO\({}_{4}\))\({}_{2}\), Table S2). BES-pH5-Invite-MgO-Ca(H\({}_{2}\)PO\({}_{4}\))\({}_{2}\) was more affected by Pb concentration due to the prevalence of Pb ions in acidic conditions, while BES-pH10-Invite-MgO-Ca(H\({}_{2}\)PO\({}_{4}\))\({}_{2}\) led to some ARGs accumulation. Pb concentration and pH were the main factors driving these shifts in microbial communities, with both microbial communities and LRGs jointly influencing ARGs dynamics. Thus, in the remediation process, the effect of LRGs on ARGs should be carefully considered. Although the synergistic remediation using composite agents and BES effectively removed most ARGs from Pb-contaminated soil, the proliferation of certain ARGs within the remediation system remained a concern. Without appropriate control measures, the environmental health risks posed by ARGs in soil may increase significantly. Therefore, it is crucial to prioritize the risk assessment of ARGs during the remediation process and to implement comprehensive control strategies aimed at mitigating the proliferation and transmission risks of ARGs. As discussed in Section 3.2, Pb concentration, pH, microbial community structure, and LRGs played significant roles in influencing ARGs dynamics during the synergistic remediation involving composite agents and BES. Several strategies can be employed to control the risks of ARGs proliferation and transmission, as illustrated in Figure 7. First, adjusting Pb stress and pH levels can effectively reduce ARGs proliferation by altering soil physicochemical properties that influence ARGs distribution. The addition of materials like biochar to remediation systems can help alleviate Pb stress and diminish selective or co-selective pressures on ARGs [44]. Second, the use of bacterial agents can promote antibiotic degradation and reduce ARGs proliferation [45]. The porous structure of certain additives may hinder direct microbial contact, thus limiting the cell-to-cell interactions that drive ARGs spread [46] Additionally, reshaping the microbial community structure can help mitigate ARGs transmission risks. Studies have shown that the addition of exogenous functional bacteria can regulate the microbial community and improve ARGs removal [5; 47; 48; 49]. Continuous monitoring of soil parameters and real-time tracking of related changes are essential, as the risk of ARGs proliferation is dynamic and varies with soil conditions.