Spatial variability, source identification and risks assessment of antibiotics in multimedia of North China's largest freshwater lake using positive matrix factorization and Monte Carlo simulation

Source orientation, environmental fate, and risks of antibiotics in the surface water of the largest sediment-laden river

Antibiotics present a more complex pollution profile in large rivers, particularly in suspended sediment-laden flows. This study quantified 25 antibiotics in surface water samples from the whole sediment-laden Yellow River. A new comprehensive prioritization index (CPI) was developed to identify priority risk control regions. The concentrations of the detected antibiotics ranged from 0.670 to 232 ng/L (mean: 9.62 ng/L), with the highest mean concentration observed for tetracyclines (TCs) at 20.2 ng/L. The most prominent antibiotic pollution was observed in the midstream region, with mean concentrations reaching 251 ng/L. Three SEMs were constructed for three antibiotic categories, with 75.6 % of the variation explained for SAs and CAs. Suspended particulate matter (SPM) significantly influences the environmental fate of antibiotics directly, negatively affecting TCs and QNs (λ = -0.302) but positively impacting SAs and CAs (λ = 0.475). Source apportionment precisely revealed that human sources in the midstream region and animal sources downstream contributed 80.75 % and 71.55 %, respectively. Although more than 85 % of the risk values were less than 0.1, the midstream region was identified as the priority control region (CPITOX >0.01). In particular, OFL, CTC, and ENO from human sources were the main contributors in the midstream region. This study elucidates antibiotic fate and risks in the whole sediment-laden Yellow River, providing a scientific basis for assessing pollution in other large rivers.

Contrastive cognition into the occurrence, source identification and risk assessment of antibiotics in various drinking water sources

Antibiotics are prevalent in aquatic ecosystems, particularly in critical drinking water sources, posing serious threats to human health and ecosystems. Focusing on rivers, lakes, reservoirs and groundwaters in Anhui Province (China), this study systematically investigated the occurrence, influencing factors and source apportionment of antibiotics and assessed their ecological and health risks. The results indicated that the total antibiotic concentrations ranged from 0.04 to 215.13 ng/L, and lincosamides and sulfonamides were the primary antibiotic groups, with concentrations of nd-167.00 ng/L and nd-47.38 ng/L, respectively. Specifically, lincomycin (nd-159.38 ng/L) and clindamycin (nd-100.45 ng/L) were the concentration of the two highest antibiotics, while sulfamethoxazole had the highest detection frequency (86.16 %). The total concentration of antibiotics in rivers was significantly higher than in lakes, reservoirs, and groundwaters, and the structural composition of antibiotics in groundwaters differed distinctly from that in other water sources. Nitrogen levels showed significant spatial correlation with antibiotic distribution, and anthropogenic activities may exacerbate antibiotic contamination. The study identified farmland drainage and aquaculture as the main sources of antibiotics in rivers and reservoirs, respectively, while livestock was the main source in lakes and groundwaters. The maximum ecological and human health risk quotient (8.83 and 0.32) of rivers was higher than that of other water sources. Antibiotics posing ecological risks included sulfamethoxazole, lincomycin, clindamycin, and clarithromycin, while tylosin and lincomycin exhibited potential threats to human health. Although the risks posed by individual antibiotics and their combined effects were within acceptable limits, the long-term exposure to low-dose antibiotics in drinking-water sources warrants close attention and further investigation.

Comprehensive evaluation of antibiotic pollution in a typical tributary of the Yellow River, China: Source-specific partitioning and fate analysis

The partitioning and migrating of antibiotic residues pose a considerable pollution to the river environment. However, a source-specific approach for quantifying the fate of antibiotics is lacking. To further elucidate the migration behavior of antibiotics from different pollution sources in aquatic environments, we introduced a source-specific partition coefficient (S-Kp) based on Positive Matrix Factorization (PMF) model to improve the multimedia model. This study identified six sources of antibiotic pollution in the water and sediment of the Fenhe River. Farmland drainage contributed 2.6 times more antibiotics to sediment than to surface water, whereas livestock sources contributed 0.3 times less to sediment than to water. High S-Kp values were primarily obtained from livestock, aquaculture, and farmland drainage pollution sources, with an average S-Kp value exceeding 200 L/kg. Sulfaquinoxaline (SQX) in sulfonamides (SAs) from livestock sources exhibited the highest S-Kp value of 34,740.04 L/kg. The predicted environmental concentrations indicated that almost 99 % of the antibiotics from the six sources remained in the water phase, with the highest contribution (99.9 %) of azithromycin (AZM) from livestock, pharmaceutical wastewater, and domestic sewage. This study provides novel insights into the migration of antibiotics from source-specific partitions in multimedia environments of watersheds.

Traceability analysis and risk assessment of river antibiotics based on dissolved organic matter spectral features and the positive matrix factorization receptor model

Identifying pollution sources is crucial for controlling antibiotic contamination and preventing risks to aquatic environments. This study quantified four categories of antibiotics (quinolones,macrolides, sulfonamides, and tetracyclines) in Dafeng River during the dry season using SPE-UHPLC-MS，analyzing their sources and risks. The source apportionment results for antibiotics using the Positive Matrix Factorization (PMF) model were validated against those identified based on Dissolved Organic Matter (DOM) fluorescence characteristics. Redundancy Analysis (RDA) was employed to clarify the relationship between specific source risks in the PMF model and DOM fluorescence characteristics. The findings include: (1) A total of 43 antibiotics were detected, with concentrations ranging from 19.04 to 1037.11 ng/L. The overall significant risk rate (RQ ≥ 0.01) was 55.1 %. (2) Excitation-Emission Matrix coupled with Parallel Factor Analysis (EEM-PARAFAC) identified three fluorescence components in the watershed's water body DOM: fulvic-like (C1), humic-like (C2), and tyrosine-like (C3). (3) The PMF model identified five pollution sources for antibiotics. Livestock discharge was the predominant source of concentration, while sewage treatment plants posed the primary source risk, consistent with the DOM spectroscopy results. (4) The RDA demonstrated a close relationship between DOM fluorescence characteristics and specific source risks of antibiotics.

Occurrence and risk assessment of quinolones and sulfonamides in freshwater aquaculture ponds in Northeast Zhejiang, China

Antibiotics play an essential role in the aquaculture industry, but their overuse and weak degradability inevitably lead to light to severe residues in natural and aquaculture environments. Most studies were interested in the occurrence, distribution, and ecological risks of a limited number of antibiotics in natural environments (rivers, lakes, and coastal regions) with a minor focus on antibiotic presence in either water, sediments, or organisms in aquaculture environments located in specific regions. In this study, we conducted a comprehensive investigation into the occurrence and distribution of up to 32 antibiotics [including 15 quinolones (QNs) and 17 sulfonamides (SAs)] in organisms and their corresponding environmental matrices from 26 freshwater aquaculture ponds in Northeast Zhejiang, China. A total of 13, 9, 7, and 7 antibiotics were detected in pond water, sediments, feeds, and aquaculture organisms, respectively, with concentration ranges of 0.6-92.2 ng/L, 0.4-1169.3 ng/g dw, Collapse

Key Words

• Antibiotics
• Contamination
• Cultured ponds
• Ecological risk
• Farming
• Health risk

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MESH Headings

• Water Pollutants, Chemical/analysis
• Aquaculture
• Sulfonamides/analysis
• China
• Quinolones/analysis
• Risk Assessment
• Environmental Monitoring
• Ponds/chemistry
• Anti-Bacterial Agents/analysis
• Animals
• Fresh Water/chemistry

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Affiliation(s)

Hongmei Hu Key Laboratory of Sustainable Utilization of Technology Research for Fisheries Resources of Zhejiang Province, Zhejiang Marine Fisheries Research Institute, Zhoushan 316021, PR China
Mengyu Qi Key Laboratory of Sustainable Utilization of Technology Research for Fisheries Resources of Zhejiang Province, Zhejiang Marine Fisheries Research Institute, Zhoushan 316021, PR China
Pengfei He Key Laboratory of Sustainable Utilization of Technology Research for Fisheries Resources of Zhejiang Province, Zhejiang Marine Fisheries Research Institute, Zhoushan 316021, PR China
Xuechang Chen Key Laboratory of Sustainable Utilization of Technology Research for Fisheries Resources of Zhejiang Province, Zhejiang Marine Fisheries Research Institute, Zhoushan 316021, PR China
Zhenhua Li Key Laboratory of Sustainable Utilization of Technology Research for Fisheries Resources of Zhejiang Province, Zhejiang Marine Fisheries Research Institute, Zhoushan 316021, PR China.
Heyong Cheng College of Material Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University, Hangzhou 311121, PR China.

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Source apportionment and ecological risk assessment of antibiotics in Dafeng River Basin using PMF and Monte-Carlo simulation

Antibiotics, prevalent in aquatic ecosystems, pose a grave threat to human health and the ecological well-being. This paper performed a case study on Dafeng River Basin in southern China. Specifically, techniques including positive matrix factorization (PFM) and Monte-Carlo simulation were employed to comprehensively investigate the spatial variations, possible sources, and ecological risks of antibiotics in four groups: sulfonamides (SAs), macrolides (MLs), quinolones (QNs), and tetracyclines (TCs). The major findings were as follows: first, 43 and 39 antibiotics were detected in the surface water and sediments of the basin, respectively, where the respective total content were ND-490.08 ng/L and ND-144.34 μg/kg, and the QNs and TCs were the two dominating groups. Second, the highest antibiotic content in surface water (441.43 ng/L) was observed in the midstream area, whereas the highest concentration in sediments (68.41 μg/kg) was found in the upstream region. Third, the investigation identified five sources of antibiotics discharged to surface water: domestic sewage, agricultural drainage, livestock discharge, sewage treatment plants, and aquaculture; three sources were detected for antibiotics in sediments: aquaculture, sewage treatment plants, and livestock discharge. Fourth, QNs had a significantly higher ecological risk than the other three groups of antibiotics, and livestock discharge (31.4% contribution) and aquaculture (23.4% contribution) were the main sources of risks of antibiotic contamination in Dafeng River Basin. This study is expected to provide some reference for control and risk management of antibiotic pollution in Dafeng River Basin.

Multiple antibiotic resistance and herbicide catabolic profiles of bacteria isolated from Lake Villarrica surface sediments (Chile)

Antibiotics and herbicides are contaminants of emerging concern in aquatic environments. Lake Villarrica is a relevant freshwater body in Chile and was recently designated a 'saturated nutrient zone'. Here, we investigated the occurrence of multiple antibiotic resistance (MAR) and herbicide catabolic profiles among bacteria present in the surface sediments of Lake Villarrica. The occurrence of antibiotic-resistant genes (ARGs; blaTEM, catA and tetM) and herbicide-catabolic genes (HCGs; phnJ and atzA) was investigated by qPCR. Subsequently, the presence of culturable bacteria with multiple resistance to amoxicillin (AMX), chloramphenicol (CHL) and oxytetracycline (OXT) was studied. Forty-six culturable MAR (AMX + CHL + OXT) strains were isolated and characterized with respect to their resistance to 11 antibiotics by using a disc diffusion assay and testing their ability to use herbicides as a nutrient source. qPCR analyses revealed that ARGs and HCGs were present in all sediment samples (101 to 103 gene copies g-1), with significant (P ≤ 0.05) higher values in sites near Villarrica city and cattle pastures. The plate method was used to recover MAR isolates from sediment (103-106 CFU g-1), and most of the 46 isolates also showed resistance to oxacillin (100%), cefotaxime (83%), erythromycin (96%) and vancomycin (93%). Additionally, 54 and 57% of the MAR isolates were able to grow on agar supplemented (50 mg L-1) with atrazine and glyphosate as nutrient sources, respectively. Most of the MAR isolates were taxonomically close to Pseudomonas (76.1%) and Pantoea (17.4%), particularly those isolated from urbanized sites (Pucón city). This study shows the presence of MAR bacteria with herbicide catabolic activity in sediments, which is valuable for conservation strategies and risk assessments of Lake Villarrica. However, major integrative studies on sediments as reservoirs or on the fate of MAR strains and traces of antibiotics and herbicides as a result of anthropic pressure are still needed.

Land use and spatial contiguity are key driven factors of antibiotic multimedia patterns in the megacity river network

The widespread spread of antibiotics in the environment poses a growing threat to human health. This study investigated the distribution and fate of antibiotics concerning land use characteristics, hydrological conditions, and spatial contiguity within a megacity river network. Temporally, the average concentrations of twenty antibiotics in water (354 ng/L), suspended particulate matter (SPM) (46 ng/L), and sediment (151 ng/g) during dry season were notably higher than that in the corresponding environment media (water: 127 ng/L, SPM: 2 ng/L, and sediment: 49 ng/g) during the wet season. Moreover, the inter-annual variation of antibiotics in water showed a decreasing trend. Spatially, substantial antibiotic contamination was observed in a human-intensive watershed, particularly in the upstream and central city sections. The macrolides in water were most affected by land use types and hydrological processes. Antibiotic contamination in water exhibited a stronger spatial autocorrelation compared to other media. Nevertheless, the interconnectedness of antibiotic contamination in sediments during the wet season warrants attention, and relevant authorities should enhance environmental monitoring in watersheds with pollution hotspots. Certain antibiotics, such as sulfamethoxazole, enrofloxacin, and florfenicol, were transported via urban rivers to the ocean, potentially posing environmental risks to coastal water quality. Local sources accounted for the predominant portion (>50 %) of most antibiotics in various media. The correlation distances of antibiotics in waters during the wet season could screen ecological risk prioritization in aquatic environments.

Antibiotics in Surface Sediments from the Anning River in Sichuan Province, China: Occurrence, Distribution, and Risk Assessment

The occurrence, distribution, and ecological risk assessment of 36 antibiotics from five groups, including macrolides (MLs), fluoroquinolones (FQs), tetracyclines (TCs), amphenicols (APs), and sulfonamides (SAs), were investigated for the first time in the Anning River, Sichuan Province, China. The results show that antibiotics were widely present in the sediments of the Anning River, with a total of 22 antibiotics detected. FQs were among the most abundant antibiotics, followed by TCs, MLs, APs, and SAs. The total concentrations of antibiotics in surface sediments varied from 0.05 to 53.35 ng/g, with an average of 8.09 ng/g. Among these groups, MLs, FQs, and TCs emerged as the predominant classes of antibiotics. The midstream sediments showed the highest residual levels of antibiotics, with lower levels observed in the downstream and upstream sediments. Anthropogenic activities, such as human clinical practices and animal breeding, might be sources of antibiotics released into the river. An ecological risk assessment revealed that trimethoprim from the SA group exhibited high risks, and MLs showed medium risks in the Anning River, whereas most antibiotics presented minimal to low risks. This study provides valuable information on antibiotic pollution in the upstream region of the Yangtze River, and future management measures are needed for the Anning River.

Source apportionment and predictable driving factors contribute to antibiotics profiles in Changshou Lake of the Three Gorges Reservoir area, China

Lakes, crucial antibiotic reservoirs, lack thorough exploration of quantitative relationships between antibiotics and influencing factors. Here, we conducted a comprehensive year-long investigation in Changshou Lake within the Three Gorges Reservoir area, China. The concentrations of 21 antibiotics spanned 35.6-200 ng/L, 50.3-348 ng/L and 0.57-57.9 ng/g in surface water, overlying water and sediment, respectively. Compared with abundant water period, surface water and overlying water displayed significantly high antibiotic concentrations in flat and low water periods, while sediment remained unchanged. Moreover, tetracyclines, fluoroquinolones and erythromycin posed notable risks to algae. Six primary sources were identified using positive matrix factorization model, with aquaculture contributing 21.2%, 22.7% and 25.4% in surface water, overlying water and sediment, respectively. The crucial predictors were screened through machine learning, redundancy analysis and Mantel test. Our findings emphasized the pivotal roles of water quality parameters, including water temperature (WT), pH, dissolved oxygen, electrical conductivity, inorganic anions (NO3⁻, Cl⁻ and F⁻) and metal cations (Ca, Mg, Fe, K and Cr), with WT influencing greatest. Total nitrogen (TN), cation exchange capacity, K, Al and Cd significantly impacted sediment antibiotics, with TN having the most pronounced effect. This study can promise valuable insights for environmental planning and policies addressing antibiotic pollution.

Multimedia distribution, partitioning, sources, comprehensive toxicity risk and co-occurrence network characteristics of trace elements in a typical Chinese shallow lake with high antibiotic risk

Although the combined pollution of trace elements and antibiotics has received extensive attention, the fate and toxicity risk of trace elements with high antibiotic risk are still unclear. The multimedia distributions, partitioning, sources, toxicity risks and co-occurrence network characteristics of trace elements in surface water (SW), overlying water (OW), pore water (PW) and sediment (Sedi) samples of 61 sites from Baiyangdian (BYD) Lake were investigated. The trace elements in the SW and OW are derived mainly from traffic and agricultural sources, and those in PW and Sedi samples are primarily from lithogenic and industrial sources. The total toxicity risk index (TRI) of nine trace elements (ΣTRI) in Sedi samples showed a very high toxicity risk (18.35 ± 8.84), and a high combined pollution toxicity risk (ΣΣTRI) was observed in PW (149.17 ± 97.52) and Sedi samples (46.37 ± 24.00). The co-occurrence network from SW to PW became more vulnerable. Generally, total antibiotics and TP may be keystones of trace elements in water and sediment. The high antibiotic risk significantly influenced ΣΣTRI in water samples but not in Sedi samples. The findings provide new implications for the monitoring and control of combined antibiotic-trace element pollution in shallow lakes.

Pollution levels and potential ecological risks of trace elements in relation to bacterial community in surface water of shallow lakes in northern China before and after ecological water replenishment

Ecological water replenishment is a crucial and effective measure to improve the water quality and ecological function of lakes. However, the effects of ecological water replenishment on the pollution characteristics and ecological risks of trace elements and bacterial communities in lake surface water are still kept unclear. We investigated the pollution levels and potential ecological risks for trace elements, as well as variation of the bacterial community in surface water in the BYD lake before and after ecological water replenishment. Our results revealed that higher levels and pollution indexes (Igeo) of trace metals (e.g., As, Cd, Co, Cu and Ni; p < 0.05) after ecological water replenishment were observed than before ecological water replenishment and their total potential ecological risk (∑RI) were increased. In contrast, the network complexity of these trace elements, including nodes, edges, average diameter, modularity, clustering coefficient and average pathlength showed a decrease after ecological water replenishment than before. The diversity (community richness, community diversity and phylogenetic diversity decreased) and community structure of the bacterial community in the surface water (p < 0.05) were greatly changed after ecological water replenishment than before, with the increase in heavy metal-resistant phylum (e.g., Acidobacteriota). Moreover, the concentration of trace elements and ∑RI were significantly correlated with the alpha diversity of bacterial community, as well as dissolved organic carbon (DOC) and ORP, after ecological water replenishment. The findings indicate that it is very necessary to continuously monitor trace metal pollution levels and heavy metal-resistant phylum and identify their potential pollution sources for water environment control and lake ecosystem health.