Assessment of toxicity potential of neglected Mithi River water from Mumbai megacity, India, in zebrafish using embryotoxicity, teratogenicity, and genotoxicity biomarkers.

The Mithi River begins at Vihar Lake and flows through the industrial hub of the city of Mumbai, India, and merges with the Arabian Sea at Mahim Creek. The current study was carried out to assess the ecotoxicological effects of the Mithi River surface water in zebrafish (Danio rerio) embryos. Water samples were collected from ten sampling sites (S1 to S10) located along the course of the Mithi River. The toxicity of water samples was assessed using a zebrafish embryo toxicity test (ZFET). Water samples were diluted from all sites at 1:0, 1:2, 1:4, 1:8, 1:16, 1:32, 1:64, and 1:128 times. The lowest and highest LDil 20 values for 96 h were estimated as 9.16 and 74.18 respectively for the S2 and S5 sites. The results of embryotoxicity and teratogenicity assays indicated a significant difference (p < 0.0001) between embryos exposed to control and sampling sites (except S1) for various endpoints such as mortality, egg coagulation, pericardial edema, yolk sac edema, tail bend, and skeletal deformities. The histopathological analysis revealed various lesions, ascertaining the toxic effects of water samples. The comet assay revealed significantly higher DNA damage (except S1) in embryos exposed to sites S5 and S6 with OTM values of 4.46 and 2.48 respectively. The results indicated that the Mithi River is polluted with maximum pollution load at the middle stretches. The study further indicated that the pollutants in the Mithi River (except S1) could potentially be hazardous to the aquatic organisms; therefore, continuous biomonitoring of the river is needed for its revival.

Incubation media modify silver nanoparticle toxicity for whitefish (Coregonus lavaretus) and roach (Rutilus rutilus) embryos.

Toxicological studies were performed to examine silver nanoparticle (AgNP, size: 14.4 ± 2.5 nm) transformation within three different test media and consequent effects on embryos of whitefish (Coregonus lavaretus) and roach (Rutilus rutilus). The test media, namely ASTM very hard water, ISO standard dilution medium, and natural lake water differed predominantly in ionic strength. Total silver was determined using inductively coupled plasma mass spectrometry (ICP-MS), while AgNPs were characterized by transmission electron microscopy and single particle ICP-MS. Silver species distributions were estimated via thermodynamic speciation calculations. Data demonstrated that increased AgNP dissolution accompanied by decreasing ionic strength of the test medium did not occur as noted in other studies. Further, other physicochemical parameters including AgNP size and metallic species distribution did not markedly affect AgNP-induced toxicity. Irrespective of the test medium, C. lavaretus were more sensitive to AgNP exposure (median lethal concentration after 8 weeks: 0.51-0.73 mg/L) compared to R. rutilus, where adverse effects were only observed at 5 mg/L in natural lake water. In addition, AgNP-induced toxicity was lower in the two standard test media compared to natural lake water. Currently, there are no apparent studies assessing simultaneously the sensitivity of C. lavaretus and R. rutilus to AgNP exposure. Therefore, the aim of this study was to (1) investigate AgNP-induced toxicity in C. lavaretus and R. rutilus cohabiting in the same aquatic environment and (2) the role played by test media in the observed effects of AgNPs on these aquatic species.

Current Trends and New Challenges in Marine Phycotoxins.

Marine phycotoxins are a multiplicity of bioactive compounds which are produced by microalgae and bioaccumulate in the marine food web. Phycotoxins affect the ecosystem, pose a threat to human health, and have important economic effects on aquaculture and tourism worldwide. However, human health and food safety have been the primary concerns when considering the impacts of phycotoxins. Phycotoxins toxicity information, often used to set regulatory limits for these toxins in shellfish, lacks traceability of toxicity values highlighting the need for predefined toxicological criteria. Toxicity data together with adequate detection methods for monitoring procedures are crucial to protect human health. However, despite technological advances, there are still methodological uncertainties and high demand for universal phycotoxin detectors. This review focuses on these topics, including uncertainties of climate change, providing an overview of the current information as well as future perspectives.

Emerging Marine Biotoxins in European Waters: Potential Risks and Analytical Challenges.

Harmful algal blooms pose a challenge regarding food safety due to their erratic nature and forming circumstances which are yet to be disclosed. The best strategy to protect human consumers is through legislation and monitoring strategies. Global warming and anthropological intervention aided the migration and establishment of emerging toxin producers into Europe's temperate waters, creating a new threat to human public health. The lack of information, standards, and reference materials delay effective solutions, being a matter of urgent resolution. In this work, the recent findings of the presence of emerging azaspiracids, spirolildes, pinnatoxins, gymnodimines, palitoxins, ciguatoxins, brevetoxins, and tetrodotoxins on European Coasts are addressed. The information concerning emerging toxins such as new matrices, locations, and toxicity assays is paramount to set the risk assessment guidelines, regulatory levels, and analytical methodology that would protect the consumers.

Exploring the influence mechanism of dissolved organic matter on the bioavailability and thyroid hormone disrupting effect of zinc: A case study of effluents from galvanizing plants.

The effect of dissolved organic matter (DOM) on metal bioavailability and toxicity is a complex process. Effluents from galvanizing plants containing large amounts of DOM and Zn were selected to investigate the potential influence and mechanism of DOM on Zn bioavailability and its role in inducing thyroid hormone disrupting effects. Thyroid hormone disrupting effects were evaluated using a recombinant thyroid hormone receptor ß gene yeast assay. The results suggest that Zn could be the main metal contributor to the toxic effects. Then, Zn-binding characteristics with different fluorescent components of DOM were analyzed using three-dimensional excitation emission matrix fluorescence spectroscopy (3DEEM) and revealed that Zn was more susceptible to interactions with fulvic-like materials. Furthermore, DOM altered the cellular biouptake and compartmentalization processes of Zn by downregulating Zn transmembrane transport-related genes (ZRT1, ZRT2 and ZAP1) and upregulating detoxification-related genes (COT1 and ZRC1), thus altering thyroid toxicity. These results provide comprehensive insights into the influence and mechanism of DOM on bioavailability and thyroid toxicity of Zn and suggest that the influence is associated with complex physical, chemical and biological processes, indicating that more refined medium constraints along with subtle biological reactions should be considered when predicting the bioavailability and toxicity of Zn in environmental water samples.

Impact of sublethal phenol in freshwater fish Labeo rohita on biochemical and haematological parameters.

Phenol, an aromatic chemical commonly found in domestic and industrial effluents, upon its introduction into aquatic ecosystems adversely affects the indigenous biota, the invertebrates and the vertebrates. With the increased demand for agrochemicals, a large amount of phenol is released directly into the environment as a byproduct. Phenol and its derivatives tend to persist in the environment for longer periods which in turn poses a threat to both humans and the aquatic ecosystem. In our current study, the response of Labeo rohita to sublethal concentrations of phenol was observed and the results did show a regular decrease in biochemical constituents of the targeted organs. Exposure of Labeo rohita to sublethal concentration of phenol (22.32 mg/L) for an epoch of 7, 21 and 28 days shows a decline in lipid, protein, carbohydrate content and phosphatase activity in target organs such as the gills, muscle, intestine, liver and kidney of the fish. The present study also aims to investigate the toxic effects of phenol with special reference to the haematological parameters of Labeo rohita. At the end of the exposure period, the blood of the fish was collected by cutting the caudal peduncle with a surgical scalpel. And it was observed that the red blood corpuscle count (RBC), white blood corpuscle (WBC), haemoglobin count (Hb), packed cell volume (PCV), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) values showed a decline after exposure to phenol for 7 days, while white blood corpuscle (WBC) shows an increased count. At 21 days and 28 days, all the haematological parameters showed a significant decrease.

Pollution shapes the microbial communities in river water and sediments from the Olifants River catchment, South Africa.

Human activities such as agriculture and mining are leading causes of water pollution worldwide. Individual contaminants are known to negatively affect microbial communities. However, the effect of multifaceted pollution on these communities is less well understood. We investigated, using next-generation sequencing of the 16S rRNA genes, the effects of multisource (i.e., fertilizer industry and mining) chronic pollution on bacterial and archaeal communities in water and sediments from the Olifants River catchment, South Africa. Water samples showed less microbial species diversity than sediments and both habitats displayed different microbial communities. Within each of these habitats, pollution had no effect on alpha diversity but shaped the microbial composition and taxonomy-based predicted functions. Certain prokaryotic taxa and functional groups were indicative of different degrees of pollution. Heterotrophic taxa (e.g., Flavobacterium sp.) and sulphur-oxidizing bacteria (i.e., Thiobacillus sp.) were indicators of pollution in water and sediments, respectively. Ultimately, this information could be used to develop microbial indicators of water quality degradation.

A dosage-effect assessment of acute toxicology tests of microplastic exposure in filter-feeding fish.

Abundant microplastics was found in aquatic ecosystem and aquatic organisms, which raised many concerns in public. Silver carp (Hypophthalmichthys molitrix), a species filter-feeding planktivorous fish, feed on particle between 4 and 85 µm in size, and the respiratory process works together with feeding mechanism when filtering plankton from water. The aim of this study was to assess the physiological response of silver carp exposed to 5 µm polystyrene microspheres during 48 h of exposure followed by 48 h of depuration through the gill histology, and oxidative stress biomarkers in intestine. The results revealed that microplastics can pass through the whole digestive tract of silver carp and be excreted by feces. Low microplastic concentration (80 µg/L) induced oxidative stress and up-regulation of TUB84 and HSP70 gene in intestine, and silver carp have ability to recover after the exposure to microplastic was removed. High microplastic concentration (800 µg/L) definitely cause significant damage to gills and intestines, in this situation, far beyond the possibility of fish own repair, and even when the threaten removed, silver carp can't recovery soon. Our studies assessed the dosage-effect relationship with physiological stress on silver carp when exposure to microplastics.

Exposure to a common urban pollutant affects the survival and swimming behaviour of creek chub (Semotilus atromaculatus).

Anthropogenic effects on the aquatic environment are ever present and ever increasing and while a plethora of aquatic contaminants are known to affect fishes, one ubiquitous and increasingly prevalent world-wide urban runoff pollutant is frequently disregarded, and that is pet waste. While dog waste has been identified as a significant factor contributing to bacteria and nutrient loading within receiving waters and the associated water quality changes are known to affect fishes, the impact of uncollected dog faeces on urban fish populations has never been directly investigated. In this study we exposed creek chub (Semotilus atromaculatus), a widespread tolerant stream minnow, to various realistic concentrations of dog waste as simulated urban park runoff testing both fresh and dried dog faeces in both stagnant and aerated water for 96 h to investigate the impact on fish survival and behaviour. Creek chub percentage mortality increased significantly relative to controls and across an exposure gradient and was likely caused by anoxic conditions. Survivors were initially smaller while those that died were initially larger and presented with abnormal abdominal subdermal lesions post-exposure. Additional indicators of physiological stress included significantly increased rates of aquatic surface respiration and changes in flume test derived swimming motivation metrics with increased exposure concentrations. Both mortality and behavioural responses were alleviated by aeration. Furthermore, trials with fresh and dried faeces differed only in time-to-death and swimming metrics where results from dried trials were similar to those from aerated experiments. Results demonstrated the impact that the global dog waste management problem can have on aquatic communities with effects on creek chub likely to be more severe for less pollution-tolerant species and also likely to be exacerbated under future scenarios that consider climate change and increased urbanization.

NPA-Cu2+ Complex as a Fluorescent Sensing Platform for the Selective and Sensitive Detection of Glyphosate.

Glyphosate is a highly effective, low-toxicity, broad-spectrum herbicide, which is extensively used in global agriculture to control weeds and vegetation. However, glyphosate has become a potential threat to human and ecosystem because of its excessive usage and its bio-concentration in soil and water. Herein, a novel turn-on fluorescent probe, N-n-butyl-4-(3-pyridin)ylmethylidenehydrazine-1,8-naphthalimide (NPA), is proposed. It efficiently detected Cu2+ within the limit of detection (LOD) of 0.21 µM and displayed a dramatic turn-off fluorescence response in CH3CN. NPA-Cu2+ complex was employed to selectively and sensitively monitor glyphosate concentrations in real samples accompanied by a fluorescence turn-on mode. A good linear relationship between NPA and Cu2+ of glyphosate was found in the range of 10-100 µM with an LOD of 1.87 µM. Glyphosate exhibited a stronger chelation with Cu2+ than NPA and the system released free NPA through competitive coordination. The proposed method demonstrates great potential in quantitatively detecting glyphosate in tap water, local water from Songhua River, soil, rice, millet, maize, soybean, mung bean, and milk with mild conditions, and is a simple procedure with obvious consequences and no need for large instruments or pretreatment.

New Insights into Alterations in PL Proteins Affecting Their Binding to DNA after Exposure of Mytilus galloprovincialis to Mercury-A Possible Risk to Sperm Chromatin Structure?

Mercury (Hg) is a highly toxic and widespread pollutant. We previously reported that the exposure of Mytilus galloprovincialis for 24 h to doses of HgCl2 similar to those found in seawater (range 1-100 pM) produced alterations in the properties of protamine-like (PL) proteins that rendered them unable to bind and protect DNA from oxidative damage. In the present work, to deepen our studies, we analyzed PL proteins by turbidimetry and fluorescence spectroscopy and performed salt-induced release analyses of these proteins from sperm nuclei after the exposure of mussels to HgCl2 at the same doses. Turbidity assays indicated that mercury, at these doses, induced PL protein aggregates, whereas fluorescence spectroscopy measurements showed mercury-induced conformational changes. Indeed, the mobility of the PLII band changed in sodium dodecyl sulphate-polyacrylamide gel electrophoresis, particularly after exposure to 10-pM HgCl2, confirming the mercury-induced structural rearrangement. Finally, exposure to HgCl2 at all doses produced alterations in PL-DNA binding, detectable by DNA absorption spectra after the PL protein addition and by a decreased release of PLII and PLIII from the sperm nuclei. In conclusion, in this paper, we reported Hg-induced PL protein alterations that could adversely affect mussel reproductive activity, providing an insight into the molecular mechanism of Hg-related infertility.

Comparative Toxicity of Fly Ash: An In Vitro Study.

Fly ash produced during coal combustion is one of the major sources of air and water pollution, but the data on the impact of micrometer-size fly ash particles on human cells is still incomplete. Fly ash samples were collected from several electric power stations in the United States (Rockdale, TX; Dolet Hill, Mansfield, LA; Rockport, IN; Muskogee, OK) and from a metallurgic plant located in the Russian Federation (Chelyabinsk Electro-Metallurgical Works OJSC). The particles were characterized using dynamic light scattering, atomic force, and hyperspectral microscopy. According to chemical composition, the fly ash studied was ferro-alumino-silicate mineral containing substantial quantities of Ca, Mg, and a negligible concentration of K, Na, Mn, and Sr. The toxicity of the fly ash microparticles was assessed in vitro using HeLa cells (human cervical cancer cells) and Jurkat cells (immortalized human T lymphocytes). Incubation of cells with different concentrations of fly ash resulted in a dose-dependent decrease in cell viability for all fly ash variants. The most prominent cytotoxic effect in HeLa cells was produced by the ash particles from Rockdale, while the least was produced by the fly ash from Chelyabinsk. In Jurkat cells, the lowest toxicity was observed for fly ash collected from Rockport, Dolet Hill and Muscogee plants. The fly ash from Rockdale and Chelyabinsk induced DNA damage in HeLa cells, as revealed by the single cell electrophoresis, and disrupted the normal nuclear morphology. The interaction of fly ash microparticles of different origins with cells was visualized using dark-field microscopy and hyperspectral imaging. The size of ash particles appeared to be an important determinant of their toxicity, and the smallest fly ash particles from Chelyabinsk turned out to be the most cytotoxic to Jukart cells and the most genotoxic to HeLa cells.

Underwater caustics disrupt prey detection by a reef fish.

Natural habitats contain dynamic elements, such as varying local illumination. Can such features mitigate the salience of organism movement? Dynamic illumination is particularly prevalent in coral reefs, where patterns known as 'water caustics' play chaotically in the shallows. In behavioural experiments with a wild-caught reef fish, the Picasso triggerfish (Rhinecanthus aculeatus), we demonstrate that the presence of dynamic water caustics negatively affects the detection of moving prey items, as measured by attack latency, relative to static water caustic controls. Manipulating two further features of water caustics (sharpness and scale) implies that the masking effect should be most effective in shallow water: scenes with fine scale and sharp water caustics induce the longest attack latencies. Due to the direct impact upon foraging efficiency, we expect the presence of dynamic water caustics to influence decisions about habitat choice and foraging by wild prey and predators.

Toxic effect of chronic waterborne copper exposure on growth, immunity, anti-oxidative capacity and gut microbiota of Pacific white shrimp Litopenaeus vannamei.

Copper can be accumulated in water through excessive sewage discharge or residual algaecide to generate toxic effect to aquatic animals. In this study, the juvenile of Pacific white shrimp, Litopenaeus vannamei was exposed to 0 (control), 0.05, 0.1, 0.2, 0.5 or 1 mg Cu2+ L-1 for 30 days. Growth, immune function, anti-oxidative status and gut microbiota were evaluated. Weight gain and specific growth rate of L. vannamei were significantly decreased with the increase of ambient Cu2+. Enlarged lumen and ruptured cells were found in the hepatopancreas of shrimp in the 0.5 or 1 mg Cu2+ L-1 treatment. Total hemocyte counts of shrimp in 0.5 or 1 mg Cu2+ L-1 were significantly lower than in the control. The hemocyanin concentration was also significantly increased in 0.2 or 0.5 mg Cu2+ L-1. Lysozyme contents were reduced in shrimp when Cu2+ exceeded 0.2 mg L-1. Meanwhile, activities of superoxide dismutase and glutathione peroxidase were increased in the hepatopancreas and the activity of Na+-K+ ATPase was decreased in the gills with increasing Cu2+. The mRNA expressions of immune deficiency, toll-like receptor and caspase-3 were all significantly higher in the hepatopancreas in 0.05 mg Cu2+ L-1 than in the control. For the diversity of intestinal microbes, Bacteroidetes significantly decreased in 1 mg Cu2+ L-1 at the phylum level. KEGG pathway analysis demonstrates that 1 mg L-1 Cu2+ can significantly alter metabolism, cellular processes and environmental information processing. This study indicates that the concentration of 1 mg L-1 Cu can negatively impact growth, hemolymph immunity, anti-oxidative capacity and gut microbiota composition of L. vannamei.

Potentially toxic element (PTE) levels in maize, soil, and irrigation water and health risks through maize consumption in northern Ningxia, China.

BACKGROUND: Industrial and agricultural activities result in elevated levels of potentially toxic elements (PTEs) in the local environment. PTEs can enter the human body through the food chain and pose severe health risks to inhabitants. In this study, PTE levels in maize, soil, and irrigation water were detected, and health risks through maize consumption were evaluated. METHODS: Maize, soil, and irrigation water samples were collected in northern Ningxia, China. Inductively coupled plasma-optical emission spectrometry was applied to determine the contents of six PTEs. Bioaccumulation factor was used to reflect the transfer potential of a metal from soil to maize. Health risks associated with maize consumption were assessed by deterministic and probabilistic estimation. Sensitivity analysis was performed to determine variables that pose the greatest effect on health risk results. RESULTS: The levels of Pb and Cr in maize exceeded the standards, while the PTE levels in soil and irrigation water did not exceed the corresponding standards. The bioaccumulation factor values of the six PTEs in maize were all lower than 1 and followed the order of Cd > Zn = As > Cr > Cu > Pb. The hazard index (0.0986) was far less than 1 for all inhabitants implying no obvious non-carcinogenic risk. The carcinogenic risk value was 3.261 × 10- 5, which was lower than the maximum acceptable level of 1 × 10- 4 suggested by United States Environmental Protection Agency (USEPA). Females were at greater risk than males, and the age group of below 20 years had the greater risk among all the groups evaluated. Approximately 0.62% of inhabitants exceeded the level for non-carcinogenic risk, while 8.23% exceeded the level for carcinogenic risk. The As concentration and daily intake of maize contributed 35.8, and 29.4% for non-carcinogenic risk results as well as 61.0 and 18.5% for carcinogenic risk results. CONCLUSIONS: Maize was contaminated by Pb and Cr, whereas the associated soil and irrigation water were not contaminated by PTEs. Inhabitants would not suffer obvious harmful health risks through maize consumption. Arsenic level and daily intake of maize were the most sensitive factors that impact health risks.

Morphological abnormalities in fish parasites: a potential tool for biomonitoring natural contaminants?

A comparative study on the strobilar morphology of the tapeworm Proteocephalus percae (Müller, 1780) (Cestoda), a parasite of the perch Perca fluviatilis (L.), showed a high percentage of abnormally developed parasite individuals. The evaluation of biological samples showed seven types of morphological abnormalities, mostly related to reproductive organs of the model tapeworm species. The most commonly identified deformity was an incomplete segmentation of the strobila. A malformed ovary, which is a structural anomaly linked with proglottization and maturation of the strobila, was also shown to be rather frequent. Offish hosts (P. percae) were collected from two localities with different levels of heavy metal pollution, the highly contaminated water reservoir Ruzín and a control locality, the water reservoir Palcmanská Masa, which belongs to the European network of protected areas in Slovakia. Tapeworm abnormalities occurred more frequently in individuals from the contaminated environment (29.9%) compared with individuals from the control site (4.9%). The concentrations of heavy metals found in the parasites and their fish hosts from the heavily polluted reservoir support our assumption that the occurrence of abnormalities could be linked with the destructive effect of toxic substances. The present study also demonstrates that the enumeration of body deformities exceeding the common level of phenotypic variability of particular parasitic species could potentially be used as an indicator of environmental problems.

Population response modeling and habitat suitability of Cobitis choii fish species in South Korea for climate change adaptation.

Endangered species ecosystems require appropriate monitoring for assessing population growth related to the emerging pollutants in their habitat conditions. The response of population growth of Cobitis choii, an endangered fish species, under the exposure to emerging pollutants present in the Geum River Basin of South Korea was studied. Toxicity models of concentration addition (CA), independent action (IA), and concentration addition-independent action (CAIA) were implemented utilizing the concentration of a set of 25 chemicals recorded in the study area. Thus, a population-level response analysis was developed based on the abundance of Cobitis choii for period 2011-2015. The results were compared showing that the CA and IA models were the most conservative approaches for the prediction of growth rate. Further, a standard abnormality index (SAI) and habitat suitability (HS) indicators based on the climate, habitat, and abundance data were presented to completely analyze the population growth of the species. Suitability of the species growth was most probable for year 2015 for the variables of air temperature and land surface temperature. A spatial analysis was complementarily presented to visualize the correlation of variables for the best suitability of the species growth. This study presents a methodology for the analysis of the ecosystem's suitability for Cobitis choii growth and its assessment of the chemicals present in Geum River stream.

Maternal inorganic mercury exposure and renal effects in the Wanshan mercury mining area, southwest China.

This study evaluated the relationship between urine mercury (UHg) concentrations and renal function (serum creatinine (SCr) and blood urea nitrogen (BUN)) in delivery women in the Wanshan mercury (Hg) mining area. Leishan County was selected as the control area. 165 and 65 maternal samples were collected from the Wanshan and Leishan area, respectively. The geometric means of UHg concentrations were 1.09 and 0.29 µg/L in Wanshan and Leishan subjects, respectively. Significant differences (p < 0.01) of UHg were observed between the two populations, indicating the potential risks of inorganic Hg exposure in the Wanshan population. The median (interquartile range) values of SCr were 69.1 (12.5) µmol/L and 46.0 (11.0) µmol/L for the Wanshan and Leishan populations, respectively, indicating significant differences (p < 0.01) between the two groups. However, no significant differences among BUN values for the two groups were observed. A significant positive correlation (r = 0.385, p < 0.001) was observed between UHg concentration and SCr in the study population. The odds ratio (OR) value of UHg in Wanshan area was 9.29 times higher than that in Leishan area (95% confidence interval (CI): 3.58-24.1). The OR value of SCr decrease in patients with low UHg was 0.32 times higher than that in patients with high UHg (95% CI: 0.19-0.55). The OR value of SCr decrease in the population with fish consumption was 0.71 times higher than that of the population without fish consumption (95% CI: 0.58-0.88). In conclusion, maternal IHg exposure caused impaired renal function and fish consumption may play a role in preventing Hg-induced nephrotoxicity.

Environmental resistome risks of wastewaters and aquatic environments deciphered by shotgun metagenomic assembly.

In this paper, we deciphered the core resistome disseminating from hospital wastewater to the aquatic environment by characterising the resistome, plasmidome, mobilome and virulome using metagenomic analysis. This study also elucidated different environmental resistome risks using shotgun-metagenomic assembly. The results showed that clinically relevant taxa were found in assessed matrices (Salmonella spp., Acinetobacter spp, Escherichia-Shigella spp., Pseudomonas spp., Staphylococcus spp. and Vibrio spp.). For the plasmidome, we found 249 core plasmidome sequences that were shared among all assessed matrices. The core mobilome of 2424 mobile genetic elements shared among all assessed matrices was found. Regarding the virulome, we found 148 core virulence factors shared among all assessed samples, and the core virulome content was consistently shared across the most abundant bacterial genera. Although influent of wastewater showed considerable higher relative bacterial abundance (P = 0.008), hospital wastewater showed significant higher environmental resistome risk scores against all other assessed matrices, with an average of 46.34% (P = 0.001). These results suggest hospital wastewater, effluent and sewage sludge should be subjected to stringent mitigating measures to minimise such dissemination.

Effects of di-n-butyl phthalate and di-2-ethylhexyl phthalate on pollutant removal and microbial community during wastewater treatment.

Due to the wide use of plastic products and the releasability of plasticizer into surrounding environment, the hazards, residues and effects of phthalic acid esters (PAEs) in ecosystems have been paid more and more attention. Little information is available about the effects of PAEs on the normal wastewater treatment, although the distribution of PAEs in soil and other ecosystems is closely related to the discharge of sewage. In this study, the effects of high concentrations of di-n-butyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP) on pollutant removal and the microbial community during landfill leachate treatment was investigated. After domestication, the activated sludge was used in the co-treatment of landfill leachate and simulated domestic wastewater. We verified that this process reduced the toxicity of landfill leachate. However, high concentrations of added DBP and DEHP were removed first, while the removal of these pollutants from raw landfill leachate was limited. The results of high-throughput sequencing revealed that the bacterial diversity was diminished and the microbial community structure was significantly affected by the addition of DBP and DEHP. The DBP and DEHP samples had 79.05% and 82.25% operational taxonomic units (OTU), respectively, in common with the raw activated sludge. Many genera of PAE-degrading bacteria that had no significant evolutionary relationship were found in the raw activated sludge. And the widespread presence of PAE-degrading bacteria could effectively keep the concentrations of PAEs low during the wastewater treatment.