Downstream Water Samples Research Articles

Composition, distribution, and risk assessment of heavy metals in large-scale river water on the Tibetan Plateau

Heavy metals present in aquatic ecosystems constitute a significant threat to both the environment and human health. In this study, we analyzed various heavy metals (As, Cr, Co, Ni, Cu, Mo, Cd, Pb and Sb) using extensive surface water samples collected from the Tibetan Plateau in 2021 and 2023. Results showed that downstream water samples exhibited higher content (mean 12.6 μg/L) of heavy metals compared to those from the glacier basins. It is noteworthy that heavy metal content varied significantly both in the glacier basin and downstream (4.6–29.1 μg/L and 7.8–55.2 μg/L, respectively). However, elevated concentrations at certain sites (e.g., Saga County and Dangque Zangbu River) were primarily attributed to the disproportionate contribution of individual heavy metals, possibly stemming from specific human activities or natural conditions. In the glacier basin, only Cr exhibited a decreasing trend in enrich factors (EF) with increasing Sc concentration, whereas, in the downstream areas, most elements displayed a declining trend. Furthermore, apart from a few sampling sites, heavy metal concentrations in the glacier basin remained relatively balanced, suggesting that these metals predominantly originate from natural sources. The values of potential ecological risk for an individual element (Eri) and potential ecological risk index (PER) indicate that the ecological and human risks associated with almost heavy metals (except As) in the aquatic ecosystem are minimal. Environmental ImplicationHeavy metals in aquatic ecosystems pose a significant threat to ecological and human health. Due to delicate ecological balance of the Tibetan Plateau and its critical role as a water resource, we analyzed various heavy metals (As, Cr, Co, Ni, Cu, Mo, Cd, Pb and Sb) concentrations and EF in land surface river water, to find out the pollution levels and possible sources of heavy metals in the aquatic ecosystems. The results of risk assessment showed that the prevention and management of arsenic in Tibetan Plateau needs attention, but most heavy metals pose no threaten to ecological and human health.

Water Quality Assessment in an Area Degraded by Urban Solid Waste in Southern Brazil

ABSTRACTIn most Brazilian municipalities, urban solid waste (USW) is disposed of in open dumps, with numerous sites now being closed, monitored, and rehabilitated. One location, the “old dump” area in the Portão municipality (southern Brazil), previously served as an irregular repository for USW and industrial solid waste (ISW). Its use continued until 1993 when it was closed for a natural remediation process. For this reason, this study aimed to assess groundwater quality in the Portão “old dump,” employing physicochemical, microbiological, and toxicity quality indicators. The study's scope was extended to encompass the Portão Stream as well. Notably, the second collection campaign revealed elevated dissolved aluminum (Al3+), iron (Fe2+), and nitrate levels in all groundwater samples (from PZi wells, i = 1–6), with the PZ3 monitoring well experiencing the most pronounced impact. Further quality indicators, such as total phosphorus, thermotolerant coliforms, BOD5, as well as Al3+ and copper (Cu2+) levels in the second water collection campaign from Portão Stream, were classified as Class 4, suggesting that the water is suitable only for navigation and aesthetic purposes. Conductivity analysis identified Portão Stream as another impacted area. Moreover, during the second collection campaign, the study uncovered an escalation in micronuclei (MN) frequency and chromosomal alterations in PZ5. Downstream water samples from Portão Stream exhibited similarly heightened MN levels. This study's investigation into water quality is a concrete example of the implications of improper USW management. These findings underscore the pressing need for effective waste management strategies to mitigate environmental degradation and protect public health.

Beneficial and adverse effects of dam construction in canal tannery wastewater effluent with a high content of chromium in Hazaribagh, Bangladesh

BackgroundBlockage to divide downstream canals into upstream canals, into which tannery wastewater including a high concentration of trivalent chromium [Cr(III)] is directly discharged, has been constructed in Hazaribagh, a tannery built-up area in Bangladesh. However, there has been no study to verify the environmental significance of blockage construction for water pollution of Cr in nature. MethodsConsecutive fixed area monitoring for a total of 164 water samples collected outside and inside Hazaribagh from 2014 to 2023 was carried out to clarify the effects of stagnant and flowable canal water in the presence or absence of blockage on Cr(III) and hexavalent Cr [Cr(VI)] concentrations. ResultsSince pollution of Cr(III) and Cr(VI) in Buriganga River (outside Hazaribagh) was not serious, this study then focused on their pollution in canal water (inside Hazaribagh) in the nonblockage period, blockage construction period and blockage destruction period. As expected, the mean Cr(III) concentration in downstream canal water samples in the blockage construction period was more than 98% lower than that in the upstream canal water samples in the same period, while the concentrations were comparable in downstream and upstream canal water samples in the nonblockage period and blockage destruction period. Unexpectedly, the mean concentration of Cr(VI) in the upstream canal water samples in the blockage construction period was 38.6-fold and 3.3-fold higher than that in the downstream canal water samples and the Cr(VI) guideline value by the US-EPA, respectively. ConclusionThis study demonstrated for the first time not only a merit of decreased Cr(III) pollution but also a demerit of increased Cr(VI) pollution in stagnant water derived from blockage construction in natural environments. This bitter lesson obtained by the enclosure of Cr(III)-polluted water is globally applicable for water pollution of Cr(III), which is used in various industries including the leather industry.

Chicken feedlot revisited: Co-dispersal of antibiotic and metal resistome under banning in-feed veterinary antibiotics

Intensive livestock farming has been implicated as a notorious hotspot for antibiotic resistance genes (ARGs) due to the excessive or inappropriate use of in-feed antibiotics over the past few decades. Since China implemented a ban on the use of antibiotics in animal feed since 2020, the dissemination of ARGs in the vicinity of feedlots has remained unclear. This study presents a case study that aims to investigate the dispersal of antibiotics and ARGs from a chicken feedlot (established in 2020) to the adjacent aquatic and soil environments. Comparing the sample collected from upstream area, the water and sediment samples from midstream and downstream areas showed an increase in total antibiotic residues and metal content (Cu and Zn) by 4.2–5.3 fold and 1.3–22.6 fold, respectively. The downstream water samples exhibited a 2.49–2.93-fold increase in the abundance of ARGs and a 1.48–1.75-fold increase in the abundance of metal resistance genes (MRGs). The results of Pearson correlation and metagenome-assembled genome revealed a tendency for the co-occurrence of ARGs and MRGs. The dissemination of ARGs and MRGs is primarily driven by tetracycline, tylosin, Cu, and, Mn, with mobile genetic elements playing a more significant role than bacterial communities. These findings shed light on the overlooked co-dispersal pattern of ARGs and MRGs in the environment surrounding feedlots, particularly in the context of banning in-feed veterinary antibiotics.

Impact of shale gas wastewater discharge on the trace elements of the receiving river in the Sichuan Basin, China.

The potential contamination of shale gas wastewater generated from hydraulic fracturing to water resources is of growing concern, yet minimum attention has been paid to the impact of shale gas wastewater on the trace elements of the receiving waters. In this study, we analyzed the levels of 50 trace elements of a river that receives effluent from a shale gas wastewater treatment facility in the Sichuan Basin, China. Sixteen trace elements were detected in the surface water sample from the effluent discharge site, all of which were of higher concentrations than the upstream background level. Among the 16 shale gas wastewater-related elements, Sr, Ba, and Li were of elevated levels in the downstream water samples (24.9-44.2%, 5.0-8.0 times, and 17.8-22.8 times higher than the upstream background level, respectively). Shale gas wastewater effluent may be related to the accumulation of Sr, Ba, Li, and Cs in riverbed sediments near and/or downstream of the effluent discharge site and may lead to elevated pollution level of Sr and Li in downstream sediments. The ecological risk of the riverbed sediments was of medium to high level, with Cd contributing to the most risk, while shale gas wastewater-related elements are of low potential risk throughout the river. Our results suggested that shale gas wastewater effluent discharge had limited impacts on the trace elements of the receiving river within two years.

Microbiology and Physicochemical Characteristics of Surface Water from a Local Refinery Site in Port Harcourt, Nigeria

Water plays a vital role in maintaining human health but due to an increase in industrialization, urbanization and other anthropogenic activities, surface water pollution is on an increase. This research was carried out to investigate the microbiological and physicochemical status of a crude oil polluted surface water in Iwofe River, Rumuolemini, Port Harcourt. Samples were collected from two points (Upstream and Downstream) bi-monthly for a period of three months. The THB counts for the upstream and downstream samples were 1.7 × 108cfu/ml and 1.4 × 108 cfu/ml, respectively while the THF counts for the samples were 3.0 × 106cfu/ml and 1.4 × 106 cfu/ml, respectively. Hydrocarbon utilizing bacterial (HUB) counts were higher in the upstream (1.5 × 106cfu/ml) than downstream (4.3 ×105cfu/ml) location of the Iwofe River. The Hydrocarbon utilizing fungal (HUF) count ranged from 1.0 × 105cfu/ml to 1.4 × 105 cfu/ml in the upstream and downstream water samples, respectively. The results of all the microbiological parameters analyzed indicated that the total heterotrophic bacterial (THB) and Total heterotrophic fungal (THF) counts were higher in the upstream than in the downstream location. The Most Probable Number (MPN) method used for the determination of coliform counts revealed the presence of coliforms both upstream and downstream, with an MPN index of 1,600/100ml of each sample. Some of the bacterial species isolated were Staphylococcus aureus, Escherichia coli and Vibrio cholerae while the fungal isolates included Aspergillus fumigatus, Penicillium species and Alternaria species. The high level of oil contamination poses a great health threat and there is a need for remediation of the aquatic ecosystem.

Distribution, composition and risk assessment of PAHs and PCBs in cryospheric watersheds of the eastern Tibetan Plateau

Polycyclic Aromatic Hydrocarbons (PAHs) and Polychlorinated Biphenyls (PCBs) are significant components of persistent organic pollutants (POPs) and pose a threat to both ecosystems and human health. To explore their spatial distribution, origins, and risk assessment, we collected 25 glacial meltwater and downstream river water samples in the eastern Tibetan Plateau (including the Qilian Mountains in the northeast) during the summer of 2022 (June–July). Our results showed that ∑PAHs and ∑PCBs were present in a wide range from ND-1380 ng/L and ND-1421 ng/L, respectively. Compared to other studies worldwide, the ∑PAHs and ∑PCBs in the Hengduan Mountains were at high levels. The PAHs and PCBs mainly consisted of low-molecular-weight homologs, including Ace, Flu, Phe, and PCB52. Phe was the primary component of PAHs. Glacial meltwater samples generally exhibited low concentration of PAHs and PCB52, whereas downstream river water samples typically showed high concentration of PAHs and PCB52. We attributed this characteristic to the influence of pollutants physicochemical properties, altitude effect, long-range transport (LRT), and local environmental conditions. In the eastern Tibetan Plateau glacier basin (especially in the Hailuogou watersheds), the concentration of PAHs and PCB52 in runoff generally increased with decreasing elevation. We believe that the primary factor affecting the concentration of PAHs and PCB52 in the region is the difference in local human activity inputs from various altitudes. The composition characteristics of PAHs and PCBs suggested that incomplete coal combustion and coking discharge mainly caused PAHs, while the combustion of coal and charcoal and the release of capacitors primarily caused PCBs. We assessed the carcinogenic risk of PAHs and PCBs in the glacier basin of the TP and found that the potential threat of PAHs was stronger than that of PCBs. Overall, this study provides new insights into the ecological security of water resources in eastern Tibetan Plateau. It is significant for controlling PAHs and PCBs emissions, assessing the ecological environment of the glacier watershed, and regional human health.

A look to surface water and wastewaters in Beira Baixa, Portugal: wastewater treatment plants and environmental risk

Some PhACs were not eliminated in WWTPs. Some PhACs were detected in upstream and downstream water samples. Some PhACs showed higher sensitivity for specific trophic levels.

Utilizing environmental DNA for wide-range distributions of reproductive area of an invasive terrestrial toad in Ishikari river basin in Japan

Understanding the distribution of invasive species and their reproductive area is crucial for their managements after invasion. While catch and observation surveys are still embraced, environmental DNA (eDNA) has been increasingly utilized as an efficient tool for identifying these species in the wild. In this study, we developed a Bufo-specific eDNA assay for detecting an invasive, toxic, and terrestrial toad species Bufo japonicus formosus in Hokkaido, Japan, and applied it to their reproductive area at watershed scale. The eDNA assay was field-validated in ponds where B. japonicus were observed, as well as in rivers downstream of the reproductive ponds. Thus, the assay provided us an opportunity to screen watersheds that include their reproductive area by collecting downstream water samples. Applying it to the Ishikari river basin, the largest river basin in Hokkaido (c.a., 14,330 km2), we detected toad eDNA at 32 out of 73 sampling sites. They are composed of eleven sites with species observation records nearby (all the sites with observation records within a 500 m radius) and 21 sites without such records. And those eDNA detections were from twelve out of 31 river systems in the entire river basin. A Bayesian, multiscale occupancy model supported high eDNA detectability among those sites. These results suggest that the eDNA assay can efficiently estimate the presence of reproductive area of the terrestrial toad even from a distant downstream of the watershed, and that it provides a powerful means of detecting new reproductive area and monitoring further spread of invasive species.

Assessing the distributions and fate of household and personal care chemicals (HPCCs) in the Songhua Catchment, Northeast China

Many household and personal care chemicals (HPCCs) are of environmental concern due to their potential toxicity to humans and wildlife. However, few studies investigate the spatiotemporal variations and fate of HPCCs in large-scale river systems. Here, river water and sediment samples from the Songhua River in Northeast China were analyzed for seven classes of HPCCs. Correlation analysis suggested similar sources and environmental behavior for compounds from the same HPCC classes. In the river water, the concentrations of most HPCCs in the cold season were significantly higher than that of the warm season (p < 0.01). Significantly higher levels of target compounds were found in the downstream water samples of a city, suggesting the influence of human activities on the distributions of HPCCs. The concentrations and distributions of most HPCCs were controlled by primary emission sources. The derived dissolved concentrations of HPCCs suggested that small amounts of caffeine and parabens were partitioned onto particles, while large amounts of many other HPCCs were bound to the particle phase. Water-sediment distribution coefficients (log Kd) ranged from 1.59 for caffeine to 3.95 for benzalkonium chloride-C14. This work presents new insights into the environmental behavior of HPCCs and the factors affecting their fate in river systems.

PRELIMINARY ANALYSES OF THE EFFICIENCY OF SUSTAINABLE FILTERS AND HYDROELETRIC POTENTIAL FOR A CLEAN ENERGY GENERATION AND WATER DEPOLLUTION SYSTEM

In last decades, water pollution has become more pronounced on all rivers in Latin America, Africa and Asia. Thus, it is estimated that the deterioration of water quality will extend further over the coming decades, increasing threats to human health, environment and sustainable development. Simultaneously, it has been observed a depletion of non-renewable energetic sources and its increasing replacement by renewable sources. Therefore, the United Nations (UN) has been setting goals regarding sustainable development for the countries. Thus, the present study aimed to create and design a mechanism that integrates clean energy generation and water depollution from small and medium-sized streams by using agro-industrial waste. For this, it was necessary to survey the theoretical framework besides the hydrological study of Pinhalzinho II watershed, which was chosen for the simulation. Thus, it was started the design of the hydroelectric microcentral coupled to a sustainable water purification system using the softwares: AutoCAD© and SketchUp 3D©. In addition, the stream flow was determined and its energy potential was calculated in order to estimate the amount of energy that could be generated by the system. Then, laboratory scale filters were constructed from sugarcane bagasse and cassava peel for efficiency analyses. Finally, the upstream (raw water) and downstream (after filtering) water samples were analyzed and their parameter values determined. After data treatment, it was found that the results were not satisfactory; conversely, they showed a reduction in raw water quality, achieving efficiency only for the thermotolerant coliforms parameter. Nevertheless, regarding the hydroelectric microcentral project and the hydroenergetic potential of the stream, the results were promising.

Biogeochemical Controls on 13CDIC Signatures from Circum-Neutral pH Groundwater in Cu–W–F Skarn Tailings to Acidic Downstream Surface Waters

Regular features of ground and surface waters affected by drainage from mine waste include their acidity and elevated concentrations of dissolved metals, with their attendant negative effects on drinking water quality and aquatic life. One parameter that aids in buffering these waters against acidity and sustains aquatic life is dissolved inorganic carbon (DIC). In this study, the chemical and isotopic (δ13C) composition of primary calcite and DIC (δ13CDIC) in groundwater and surface waters within and downstream, respectively, of abandoned Cu–W–F skarn tailings at Yxsjöberg, Sweden, were used to trace the biogeochemical processes controlling their respective δ13CDIC signatures. In addition, the δ13C signatures of the inorganic (carbonate) fractions of the tailings were used to verify the formation of secondary carbonates within the tailings. Lower average δ13C values of the carbonate fractions (δ13Ccarb = −2.7‰) relative to those of the primary calcite (δ13C = +0.1‰) from the orebodies from which the tailings originated pointed to the precipitation of secondary carbonates. These lower δ13Ccarb signatures were assumed to represent mixed-source C signals involving isotopically light CO2 from the atmosphere, the degradation of organic matter in the upper part of the tailings and HCO3− from calcite dissolution. The groundwater δ13CDIC values (−12.6‰ to −4.4‰) were far lower than the hypothetical range of values (−4.6‰ to +0.7‰) for primary calcite and secondary carbonate dissolution. These signatures were attributed to carbonate (calcite and secondary carbonate) dissolution and the degradation of dissolved organic carbon (DOC) from various organic sources such as peat underneath the tailings and the surrounding forests. Downstream surface water samples collected in May had low δ13CDIC values (−16‰) and high DOC (14 mg C/L) compared to the groundwater samples. These signatures represented the oxidation of the DOC from the wash out of the mires and forests during the snowmelt and spring flood. The DOC and δ13CDIC values of the surface waters from June to September ranged from 6–15 mg·C/L and −25‰ to −8.6‰, respectively. These signatures were interpreted to reflect mixed C sources, including carbonate dehydration by acidity from Fe3+ hydrolysis due to the mixing of groundwater with surface waters and the subsequent diffusive loss of CO2 (g), aquatic photosynthesis, photooxidation, DOC degradation, as well as microbial respiration. Although the 13CDIC signatures of the downstream surface waters seemed to be seasonally controlled and influenced by variable groundwater contributions, the lack of data with respect to DIC concentrations, coupled with multiple potential biogeochemical processes that could influence the DIC pool and 13CDIC values, made it difficult to identify the major regulating process of the 13CDIC signatures. Therefore, other complimentary isotopes and elemental concentrations are recommended in order to decipher the dominant biogeochemical process.

Leachate Characterization from Municipal Solid Waste Dump Site and Its Adverse Impacts on Surface Water Quality Downstream - Uyo Village Road, Akwa Ibom State - Nigeria

The present investigation discusses the characteristic of leachate generated from municipal solid waste landfill and it adverse impacts on downstream water quality. Landfill leachate was collected from a hole dug 10 m away from the waste dump site and the appearance of the leachate sample looks black. Three downstream water samples were collected at 10 meters intervals each from each other and less than 100 meters from the boundary of the dumpsite. All the samples were examined for temperature, pH, TDS, TSS, BOD, COD, nitrate, ammonia, Cu, Ni, Pb, Cd, Cl, total phosphate, sulfate, EC, DO and turbidity. The aim was to compare physicochemical and heavy metal properties of leachate and downstream water quality with internationally accepted protocols. The Laboratory analysis exhibited prevalence of high value of pH (8.5130.09), temperature(29.00.0), turbidity (14.00.41NTU), DO (0.1670.05 mg/l), COD (68.00.33 mg/l), BOD5 (324.03.00 mg/l), EC (446315.53s/cm), Total phosphate (62.3580.01 mg/l), Pb (0.310.00 mg/l), Cd (0.060.00 mg/l), Ni (0.3550.01 mg/l), and Cu (8.670.04 mg/l) in the leachate sample, which have exceeded their permissible limits. For downstream water samples, pH (7.760.07 to 7.5070.09), temperature (29.00.00) for the three sampling points, DO (3.6670.15 to 3.2330.12 mg/l), total phosphate (8.2250.00 to 7.9350.02 mg/l), Pb (0.4650.01 to 0.0910.00 mg/l), Cd (0.040.00 to 0.0230.00 mg/l), Ni and Cu (0.0430.06 mg/l) and (1.0620.00 mg/l) respectively, also exceeded their respective permissible limit recommended by Nigerian Standard for Drinking Water Quality, World Health Organization in drinking water quality. From this study, there is evidence that there is an increase in risk to surface water that is reported near Uyo village road municipal solid waste dumping site. Therefore, the concerned authority should take appropriate intervention measures to protect surface water. Also, knowledge of leachate quality will be useful in planning and providing remedial measures to protect downstream water quality in the area.

Assessment of lowest chromium bioaccumulation vegetables irrigated by Sheba Leather Industry contaminated water in Wukro, Tigray – Ethiopia

High chromium concentration is threatening to the environment, since it is persistent and non-biodegradable pollutant while introduced once to our planet. Bioaccumulation capacity of chromium has carcinogenic potential to human beings. To minimize the risk of chromium bioaccumulation, the study was conducted in Wukro irrigation fields. 54 plants, 24 water and 18 soil samples were collected in triplication from the selected points of upstream, treatment plant and downstream of the Sheba leather industry. Samples were transported to advanced laboratory for chromium analysis and results were analysed by R-software. Downstream vegetable samples were measured higher chromium bioaccumulation compared to the upstream sites. Highest chromium concentration was recorded in rood edible vegetables, and the lowest was measured in fruit edible vegetables. Chromium concentration was significantly different between the upstream and downstream vegetables, water and soil samples at p&lt;0.01, p&lt;0.05 and p &lt; 0.001 respectively. The chromium bioaccumulation order were root edible &gt; leaf edible &gt; fruit edible vegetables. Environmental laws have to be strictly enforced and further researches are recommended.

Selected Toxic Heavy Metals Levels in Vegetables, Soil and Irrigation Water at Awashriver, Ginchi Town, West Shoa Zone, Ethiopia

The levels of selected heavy metals (Cr, Cd and Pb) have been determined in cabbage, onion, soil and Awash river used for irrigation have been investigated. The cabbage, onion, soil and Awash River water samples were collected from the farmlands around Ginchi Town of West Shoa Zone in which the Anmol Ethiopia PLC, a paper industry, were there. The samples were digested using properly optimized wet digestion procedures. The metal contents were analyzed using Flame Atomic Emission Spectroscopy (FAES). However, Cd and Pb were not detected in all samples. Likewise, the highest level in onion samples was, Cr(0.59 mg/L). High concentrations of Cr (71.85 mg/Kg) were detected in soil samples on which the Onion vegetable was gown, while the corresponding values of Cr detected in the Onion sample itself was 59.35 mg/Kg. The levels of selected metals in downstream water (after effluent from Anmol Production Ethiopia PLC is mixed with Awash River) samples used for irrigation. It can be concluded that, Cr in both soil onion and onion exceeded the FAO limit of maximum recommended level vegetable plant, so that the consumption of this Onion might cause hazards with respective to Cr and hence care must be taken. Key phrases : toxic heavy metals, soil, vegetables, irrigation water DOI: 10.7176/CMR/12-2-04 Publication date: February 29 th 2020

Contamination features, geo-accumulation, enrichments and human health risks of toxic heavy metal(loids) from fish consumption collected along Swat river, Pakistan

Abstract Toxic heavy metal(loids) (THMs) are released into natural water systems from geological and anthropogenic sources, and easily accumulated via water and sediments in aquatic fish species. The monitoring of THM concentrations in river water, sediments and fish muscles is therefore, essential to make sure acquiescence with food security guidelines and resulting end user safety. The present study aimed to investigate the concentrations of arsenic (As), cadmium (Cd), lead (Pb), chromium (Cr), copper (Cu), nickel (Ni) and zinc (Zn) in water, bed sediments and their bioaccumulation in freshwater fish tissues collected from five locations along Swat River, Pakistan. Results indicated that Cd concentration in the downstream (30%) water samples exceeded the safety guideline values of World Health Organization (WHO), while the other selected THMs were within the safety limits. The ecological risk ( E ri ) for sediments showed considerable ecological risk (80 ≤ Eri E ri >320) for Pb, As and Cd, while the potential ecological risk (RI) showed considerable level ((190 ≤ RI Cd >Pb >Cr >As >Cu >Ni. In the study area, the selected THMs were within the permissible limits all the fish tissue samples showing no potential health risk (carcinogenic and non-carcinogenic

The correlation between antibiotic resistance gene abundance and microbial community resistance in pig farm wastewater and surrounding rivers

Antimicrobial resistance gene (ARG) abundance and microbial resistance (MR) are often used as important indicators of pollution risk; however, the relationship between ARGs abundance and MR in pig farm wastewater remains unknown. In this study, the raw pig farm wastewater, effluent water, upstream river water, domestic wastewater and downstream river water samples were collected. The concentration of 20 subtypes of ARGs and 2 integrons, minimal inhibit concentration (MIC), and bacterial communities were investigated. In this study, 20 subtypes of ARGs and integrons were detected in all sampling sites. The highest abundance of 17 of the 20 subtypes of ARGs was detected in raw pig farm wastewater, and ermA had the maximum average abundance of 108 copies/mL, with up to 2.41 ± 0.12 × 108 copies/mL. There was no significant correlation between MR to three antibiotics (ciprofloxacin, streptomycin and tetracycline hydrochloride) and the abundance of their corresponding ARGs (P > 0.05), and a large difference was detected between the types of ARGs co-occur bacteria and resistance co-occur bacteria in the 5 sampling sites. And the pig farm wastewater treatment (WWT) could effectively reduce the ARGs and MR to the 3 antibiotics. The results presented here show that there may be no obvious correlation between ARGs and MCR in pig farm wastewater and surrounding rivers, which may be due to various environmental factors, highlighting the urgent need for a comprehensive evaluation of relationship between ARGs abundance and MR.

Pollution patterns and underlying relationships of benzophenone-type UV-filters in wastewater treatment plants and their receiving surface water

The environmental behaviors of emerging pollutants, benzophenone-type UV filters (BP-UV filters) and their derivatives were investigated in four wastewater treatment plants (WWTPs), and their receiving surface waters in Shanghai. The concentration level of selected BP-UV filters in the WWTPs was detected from ngL−1 to μgL−1. BP (621–951ngL−1) and BP-3 (841-1.32 × 103ngL−1) were the most abundant and highest detection frequency individuals among the target BP-UV filters in influents, whereas BP (198–400ngL−1), BP-4 (93.3–288ngL−1) and BP-3 (146–258ngL−1) were predominant in effluents. BP-UV filters cannot be completely removed and the total removal efficiency varied widely (−456% to 100%) during the treatment process. It can be inferred that the usage of BP and BP-3 are higher than other BP-UV filters in the study area. The lowest and highest levels were BP-2 (ND-7.66ngL−1) and BP-3 (68.5-5.01 × 103ng L−1) in the receiving surface water, respectively. Interestingly, the seasonal variation of BP-3 is larger than those of other BP-UV filters in surface water from Shanghai. There is no obvious pollution pattern of BP-UV filters in the surface water from the cosmetic factory area. The correlation analysis of BP-UV filters between WWTPs effluents and nearby downstream water samples suggested that BP-UV filters emitted from some WWTPs might be the main source of receiving surface water. Preliminary risk assessment indicated that the levels of BP-UV filters detected by the effluent posed medium to high risk to fish as well as other aquatic organisms.

Ecotoxicological effects of downstream wastewater samples on Cloeon perkinsi larvae, Rana temporaria tadpoles and Clarias gariepinus frys and fingerlings

Indiscriminate dumping of refuse and direct defaecation into surface water bodies alter physico-chemical qualities of the water and adversely affect the existence of certain fauna. Downstream water samples were collected from five streams (Irefin, Gege, Gbagi, Odinjo and Omi Adio) receiving domestic wastes in Ibadan and a control stream within the University of Ibadan, Oyo state, Nigeria. Physico-chemical qualities of the downstream water were analysed using standard methods.&nbsp; Acute toxicity of contaminated water was investigated on some fauna. The 48-hour-LC50 of stream samples was determined for Cloeon perkinsi (mayfly) larvae (CP); while 96-hour-LC50 for Rana temporaria tadpoles, Clarias gariepinus frys (CG1) and fingerlings (CG2) were determined using Probit method. Zero dissolved oxygen values were recorded for Irefin and Gege while 1.07 mg/L was recorded for Odinjo and these were lower than permissible limit for aquatic life. The values of biochemical oxygen demand (43.34 – 160.66 mg/L), chemical oxygen demand (136 – 487.10 mg/L) and phosphate (81.63 – 1877.60 mg/L) recorded for all the samples were significantly higher (P&lt;0.05) than the control sample and were higher than limits set by National Environmental Standards and Regulatory Enforcement Agency (NESREA). The 48-hour-LC50 of contaminated stream water to CP (Irefin, 12.67%; Gege, 8.63%), and 96-hour-LC50 to CG1 (Gege, 0.79%; Gbagi, 2.75%) and CG2 (Gege, 3.33%; Irefin, 5.64%) indicated high toxicity of the sites. High toxicity of the study sites revealed that the streams were polluted in Ibadan. Therefore, there is need for adequate management and disposal of solid wastes to prevent further environmental contamination.

Microbial diversity in an intensively managed landscape is structured by landscape connectivity

Intensively managed land increases the rate of nutrient and particle transport within a basin, but the impact of these changes on microbial community assembly patterns at the basin scale is not yet understood. The objective of this study was to investigate how landscape connectivity and dispersal impacts microbial diversity in an agricultural-dominated watershed. We characterized soil, sediment and water microbial communities along the Upper Sangamon River basin in Illinois-a 3600 km2 watershed strongly influenced by human activity, especially landscape modification and extensive fertilization for agriculture. We employed statistical and network analyses to reveal the microbial community structure and interactions in the critical zone (water, soil and sediment media). Using a Bayesian source tracking approach, we predicted microbial community connectivity within and between the environments. We identified strong connectivity within environments (up to 85.4±13.3% of sequences in downstream water samples sourced from upstream samples, and 44.7±26.6% in soil and sediment samples), but negligible connectivity across environments, which indicates that microbial dispersal was successful within but not between environments. Species sorting based on sample media type and environmental parameters was the dominant driver of community dissimilarity. Finally, we constructed operational taxonomic unit association networks for each environment and identified a number of co-occurrence relationships that were shared between habitats, suggesting that these are likely to be ecologically significant.