Distribution and occurrence characteristics of antibiotic resistance genes in China's nearshore waters: A systematic review (2016-2026).

Antibiotic resistance genes (ARGs), as emerging biological pollutants with the capacity for genetic transmission, have been widely detected in China's nearshore aquatic environments and pose potential risks to ecological security and public health. This review systematically synthesizes studies published between 2016 and 2026 on ARGs in China's nearshore waters, with a focus on their occurrence and spatial distribution, source inputs, and mechanisms of transport and dissemination. Overall, ARG abundance generally decreases from estuarine and nearshore waters toward offshore areas, although the specific spatial pattern varies among coastal systems. Estuaries, semi-enclosed bays, and coastal discharge zones are identified as hotspots. Across environmental media, ARGs exhibit multi-interface partitioning among the water column, particles, sediments, biofilms, and biota, with sediments and particle-associated fractions serving as important reservoirs. Urban and industrial wastewater effluents, riverine runoff, agricultural and livestock non-point sources, and nearshore aquaculture together form a complex multi-source input system for ARGs. Physicochemical factors, including salinity, temperature, redox conditions, particle adsorption, and sediment burial, as well as co-selection pressures from antibiotics, heavy metals, and organic pollutants, regulate the persistence and spread of ARGs through mobile genetic elements (MGEs) and horizontal gene transfer. ARGs may alter microbial community structure and biogeochemical cycling, while seafood consumption and coastal exposure represent potential pathways for human exposure to ARGs. This review clarifies the distribution patterns and environmental fate of ARGs in China's nearshore waters and provides a scientific basis for the environmental risk management of emerging pollutants in coastal zones.