Background: Antibiotics and antibiotic resistance genes (ARGs) threaten ecological sustainability and human health, especially the drinking water sources of the Douhe Reservoir, which have critical significance amid their direct use by people and the ecological hub of flora and fauna. Although antibiotics and ARGs pollution in reservoirs have been reported, it is of no practical significance to only study the changes (increase or decrease) of the abundance and diversity of ARGs, and it is more important to explore the mechanisms of the changes affecting ARGs. Thus, the occurrence and prevalence characterizations of the spatial and seasonal of the ARGs, mobile genetic elements (MGEs) and bacterial communities were comprehensively studied in present study. Results: 263 ARG (nine types of ARGs) and 51 MGE subtypes were detected in 56 samples, and the characteristics of the temporal and spatial distribution of ARGs, MGEs and the composition of bacterial communities were significantly different. Moreover, the correlation among the ARGs, bacterial communities, MGEs and environmental factors were defined, and the co-occurrence patterns associated with ARG subtypes, bacterial genera, and MGE subtypes between water and sediment of the Douhe Reservoir were different. Conclusions: In summary, ARGs were ubiquitous presence in water and sediment of the Douhe Reservoir, and the multidrug, aminoglycoside and macrolide–lincosamide–streptogramin B (MLSB) were main types of ARGs. Bacterial genera and the environmental factors [such as temperature (T), nitrate–nitrogen (NO– 3–N), total dissolved nitrogen (TDN), and total phosphorus (TP)] significantly affected the distribution pattern of ARGs. Overall, this research revealed the spatiotemporal change and transmission mechanisms of ARGs in the typical drinking water sources of reservoirs, which will supply clues to ensure the safety of water sources.

The water quality of centralized drinking water sources (CDWSs) in the Yangtze River Basin (YRB) has received widespread public attention. Regrettably, due to the lack of large-scale and high-frequency monitoring data, the trends, sources, and risks of heavy metals (HMs) in the water of CDWSs in the YRB are still unclear. In addition, the correlation between HMs and water quality parameters in natural water has not been established, which greatly affects the efficiency of water management. Herein, we collected data for eight HMs and twelve water quality physical–chemical parameters from 114 CDWSs in 71 prefecture-level cities in the YRB region. An unprecedented spatial distribution map of HMs in the YRB region was drawn, and the response of HMs to water quality and nutrient levels was studied. Overall, the level of HM pollution was low, but the threat of chloride, nitrogen, and phosphorus still exists. The detection rates of the eight HMs ranged from 60.00% (Ti) to 99.82% (Fe), and the mean concentrations were ranked as follows: Fe (36.576 ± 36.784 μg/L) > Mn (7.362 ± 7.347 μg/L) > Ti (3.832 ± 6.344 μg/L) > Co (2.283 ± 3.423 μg/L) > Se (0.247 ± 0.116 μg/L) > Cd (0.089 ± 0.286 μg/L) > Be (0.054 ± 0.067 μg/L) > Tl (0.015 ± 0.012 μg/L). In the large geographic area, the total concentrations of the eight HMs exhibited a fluctuating decay trend over time from 2018 to 2022. Geographically, industrial and agricultural production and geological coupling factors led to significant spatial heterogeneity in HM concentrations in the following order: midstream > downstream > upstream. Importantly, this study proved that Cl⁻, SO₄²⁻, nitrogen, and phosphorus may drive the absorption and transfer of HMs in natural water. Fortunately, exposure to the eight HMs does not cause adverse health effects in humans.