Presence of pharmaceuticals and heavy metals in the waters of a Mediterranean coastal wetland: Potential interactions and the influence of the environment

Mixture toxicity of the heavy metal copper and the fluoroquinolone antibiotic ciprofloxacin on Microcystis aeruginosa

Exposure to chemical mixtures is the norm in natural environments. Yet, water quality regulations are still mostly constructed for individual chemicals. However, an important ambition of the European Green Deal is the future implementation of mixture toxicity to address the risks posed by the joint presence of multiple chemicals in aquatic ecosystems (e.g., via a mixture allocation factor, MAF). This study aimed to contribute to this by investigating the ecotoxicity of a series of binary ciprofloxacin‑copper (CIP-Cu) mixtures at environmental realistic concentrations to the cyanobacterium Microcystis aeruginosa, which is the most CIP-sensitive freshwater species identified so far. The two chemicals have distinct modes of action, however, the bioavailability of both is influenced by pH. The toxicity data of CIP-Cu mixtures were analysed to examine if significant interactions exist relative to the concentration addition (CA) and independent action (IA) models. CIP-Cu mixtures behaved antagonistically relative to the CA model, whereas there was no interactive toxicity relative to the IA model, which better describes the CIP-Cu mixture toxicity, in line with expectations based on the distinct modes of action of Cu and CIP. Furthermore, attention was placed to the influence of Cu in the low-effect concentration range (≤ EC10, the 10 % effective concentration) on CIP ecotoxicity, in order to identify potential synergistic effects that may lower the toxic threshold of CIP in the presence of Cu. Across the pH range 7.3-9.0, the presence of '≤ EC10' level of Cu did not affect the EC10 of CIP. Only at pH 8.0, but not at pH 7.3 or 9.0, the addition of an (EC10)/2 level of Cu lowered the 50 % effect concentration (EC50) of CIP from 2.8 to 2.0 μg L-1. The overall observations confirmed that there are no significant interactive effects between Cu and CIP relative to the IA model. Therefore, regulatory environmental threshold concentrations for CIP derived from single-chemical tests, are protective in situations of co-occurrence with Cu, provided that Cu remains below its own environmental quality standards.

Occurrence of selected Covid-19 drugs in surface water resources: a review of their sources, pathways, receptors, fate, ecotoxicity, and possible interactions with heavy metals in aquatic ecosystems

The outbreak of the coronavirus disease 2019 (Covid-19) led to the high consumption of antibiotics such as azithromycin as well as corticosteroids such as prednisone, prednisolone, and dexamethasone used to treat the disease. Seemingly, the concentrations of these four Covid-19 drugs increased in wastewater effluents and surface water resources. This is due to the failure of traditional wastewater treatment facilities (WWTFs) to eliminate pharmaceuticals from wastewater. Therefore, the objective of the current research was to review the present state of literature on the occurrence of four Covid-19 drugs in water resources, the associated risks and toxicity, their fate, as well as the emergence of combined pollutants of Covid-19 drugs and heavy metals. From late 2019 to date, azithromycin was observed at concentrations of 935 ng/L, prednisone at 433 ng/L, prednisolone at 0.66 ng/L, and dexamethasone at 360 ng/L, respectively, in surface water resources. These concentrations had increased substantially in water resources and were all attributed to pollution by wastewater effluents and the rise in Covid-?19 infections. This phenomenon was also exacerbated by the observation of the pseudo-persistence of Covid-19 drugs, long half-life periods, as well as the excretion of Covid-19 drugs from the human body with about 30?90% of the parent drug. Nonetheless, the aquatic and human health toxicity and risks of Covid-19 drugs in water resources are unknown as the concentrations are deemed too low; thus, neglecting the possible long-term effects. Also, the accumulation of Covid-19 drugs in water resources presents the possible development of combined pollutants of Covid-19 drugs and heavy metals that are yet to be investigated. The risks and toxicity of the combined pollutants, including the fate of the Covid-19 drugs in water resources remains a research gap that undoubtably needs to be investigated.

Effects of cable bacteria on vertical redox profile formation and phenanthrene biodegradation in intertidal sediment responded to tide

Periodic oxygen permeation is critical for pollutant removal within intertidal sediments. However, tidal effects on the vertical redox profile associated with cable bacterial activity is not well understood. In this study, we simulated and quantified the effects of tidal flooding, exposing, and their periodic alternation on vertical redox reactions and phenanthrene removal driven by cable bacteria in the riverbank sediment. Results show that electrogenic sulfur oxidation (e-SOx) mediated by cable bacteria during exposing process drove the vertical permeation of oxidation potential characterized by a decrease in Fe(II) and sulfide concentrations. The sulfate produced was observed in deep sediment (5-10 mm) and served as an electron acceptor for anaerobic oxidation, thereby triggering the functional succession of microbial community. About 78.2 % and 80.8 % of phenanthrene was degraded in deep sediment where cable bacteria grew well under exposing and tidal conditions. Anaerobic processes during tidal flood were also found to be important for the survival of cable bacteria. Higher cable bacteria abundance (up to 1.5 %) was observed under tidal conditions compared to that under continuous exposing conditions and flooding conditions. This might be attributed to lower oxidation stress and sulfide replenishment via sulfate reduction while flooding. Under tidal conditions, the cable bacteria interacted with sulfate reduction bacteria (e.g. Desulfobacca spp. and Desulfatiglans spp.) and maintained the dynamic balance of HS- and SO42- in sediment profiles. This HS--SO42- cycle could serve as a "redox connector" that continuously delivers oxidation potential to deep sediments, resulting in the removal of organic pollutants. The findings provide preliminary evidence of the self-purification mechanisms within intertidal sediments and suggest a potential strategy for sediment remediation.

Efficacy of anthocyanin, kaolinite and cabbage leaves-derived biochar for simultaneous removal of lead, copper and metoprolol from water

Simultaneous removal of toxic elements and pharmaceutical compounds at environmentally relevant concentrations in aqueous solution is challenging. Modification of biochar using environmental materials has attracted significant attention in wastewater treatment, while pristine biochar has several limitations in the simultaneous removal of Lead (Pb2+), Copper (Cu2+), and metoprolol. We investigated the efficacy of biochar composites using waste cabbage leaves-derived biochar with kaolinite, and anthocyanin for simultaneous removal of Pb2+, Cu2+, and metoprolol from water. Using ball milling, the surface area and functional groups of adsorbents were improved via breaking the biochar grains into ultrafine particles. Ball-milled biochar derived from waste cabbage leaves significantly increased Pb2+, Cu2+, and metoprolol adsorption by 105, 71, and 213%, respectively. Results of Brunauer Emmett Teller surface area, Fourier transform infrared and X-ray photoelectron spectroscopies showed that surface area of non-milled biochar improved nearly ten-fold following ball-milling, while several oxygen containing acidic functional groups also increased. The adsorbents resulted in high removal efficiency for Pb2+ (162.9 mg/g) and Cu2+ (48.5 mg/g) in ball milled-kaolinite composite biochar (BMKB) and 76.3 mg/g (metoprolol), respectively in ball milled-anthocyanin composite biochar (BMAB). The simultaneous sorption of Pb2+, Cu2+, and metoprolol in an aqueous solution to BMAB and BMKB, showed that the adsorption capacity followed the order of Pb2+ >Cu2+ > metoprolol in both types of ball-milled biochars. BMKB achieved a high adsorption capacity for Pb2+ and Cu2+ (59 mg/g and 50 mg/g), respectively, while BMAB exhibited an adsorption capacity 22.3 mg/g for metoprolol. It was postulated that sorption of Pb2+, Cu2+ and metoprolol involved multiple adsorption mechanisms namely surface complexation, π-π interaction, H-bond, pore filling, and ion bridging. The findings of this study revealed that ball milling is a potential technology in producing a highlyefficient adsorbent to remediate multi-contaminants in aqueous solution.

Priority list of pharmaceutical active compounds in aquatic environments of Mexico considering their occurrence, environmental and human health risks

Pharmaceutical active compounds (PhACs) are detected pollutants in aquatic environments worldwide at concentrations ranging from ng L-1 to µg L-1. Currently, PhAC monitoring is poorly realized in Mexico. This study proposes a priority list of PhACs in Mexican aquatic environments, considering their occurrence and environmental and human health risks. Ecological risks were assessed as Risk Quotients (RQ) values using the PhAC concentrations detected in surface water, obtaining high risks (RQ > 1) against aquatic organisms, especially of naproxen, ibuprofen, diclofenac, acetaminophen, 17β-estradiol, carbamazepine, ketoprofen, caffeine. In contrast, potential human health risks (RQH) were assessed on the Mexican population using the concentrations quantified in groundwater, demonstrating potential risks (RQH > 0.2) on the population, particularly of DCF and CBZ. Thus, a priority list of PhACs can be used as a reference for environmental monitoring in Mexican water supplies as well as PhACs monitoring in countries of the Caribbean region and Central America.

Ecological and human health risk assessment of pharmaceutical compounds in the Sirsa River of Indian Himalayas

The Baddi-Barotiwala-Nalagarh (BBN) region of Indian Himalayas is one of the most important pharmaceutical industrial clusters in Asia. This study investigated the distribution, and ecological and human health risks of four most frequently used pharmaceuticals [ciprofloxacin (CIP), norfloxacin (NOR), cetirizine (CTZ) and citalopram oxalate (ECP)] when co-occurring with metal ions in the Sirsa river water of the BBN region. The concentration range of the selected pharmaceuticals was between 'not detected' to 50 μgL-1 with some exception for CIP (50-100 μgL-1) and CTZ (100-150 μgL-1) in locations directly receiving wastewater discharges. A significant correlation was found between the occurrences of NOR and Al (r2 = 0.65; p = 0.01), and CTZ and K (r2 = 0.50; p = 0.01) and Mg (r2 = 0.50; p = 0.01). A high-level ecological risk [risk quotient (RQ) > 1] was observed for algae from all the pharmaceuticals. A medium-level risk (RQ = 0.01-0.1) was observed for Daphnia from CIP, NOR and ECP, and a high-level risk from CTZ. A low-level risk was observed for fishes from CIP and NOR, whereas CTZ and ECP posed a high-level risk to fishes. The overall risk to ecological receptors was in the order: CTZ > CIP > ECP > NOR. Samples from the river locations receiving water from municipal drains or situated near landfill and pharmaceutical factories exhibited RQ > 1 for all pharmaceuticals. The average hazard quotient (HQ) values for the compounds followed the order: CTZ (0.18) > ECP (0.15) > NOR (0.001) > CIP (0.0003) for children (0-6 years); ECP (0.49) > CTZ (0.29) > NOR (0.005) > CIP (0.001) for children (7-17 years), and ECP (0.34) > CTZ (0.21) > NOR (0.007) > CIP (0.001) for adults (>17 years). The calculated risk values did not readily confirm the status of water as safe or unsafe because the values of predicted no-effect concentration (PNEC) would depend on various other environmental factors such as quality of the toxicity data, and species sensitivity and distribution, which warrants further research.

Occurrence of phthalic acid esters (PAEs) and active pharmaceutical ingredients (APIs) in key species of anthozoans in Mediterranean Sea

The Mediterranean Sea's biodiversity is declining due to climate change and human activities, with plastics and emerging contaminants (ECs) posing significant threats. This study assessed phthalic acid esters (PAEs) and active pharmaceutical ingredients (APIs) occurrence in four anthozoan species (Cladocora caespitosa, Eunicella cavolini, Madracis pharensis, Parazoanthus axinellae) using solid phase microextraction (SPME) and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). All specimens were contaminated with at least one contaminant, reaching maximum values of 57.3 ng/g for the ∑PAEs and 64.2 ng/g (wet weight) for ∑APIs, with dibutyl phthalate and Ketoprofen being the most abundant. P. axinellae was the most contaminated species, indicating higher susceptibility to bioaccumulation, while the other three species showed two-fold lower concentrations. Moreover, the potential adverse effects of these contaminants on anthozoans have been discussed. Investigating the impact of PAEs and APIs on these species is crucial, given their key role in the Mediterranean benthic communities.

Proteomic analysis of the hepatic response to a pollutant mixture in mice. The protective action of selenium

Metals and pharmaceuticals contaminate water and food worldwide, forming mixtures where they can interact to enhance their individual toxicity. Here we use a shotgun proteomic approach to evaluate the toxicity of a pollutant mixture (PM) of metals (As, Cd, Hg) and pharmaceuticals (diclofenac, flumequine) on mice liver proteostasis. These pollutants are abundant in the environment, accumulate in the food chain, and are toxic to humans primarily through oxidative damage. Thus, we also evaluated the putative antagonistic effect of low-dose dietary supplementation with the antioxidant trace element selenium. A total of 275 proteins were affected by PM treatment. Functional analyses revealed an increased abundance of proteins involved in the integrated stress response that promotes translation, the inflammatory response, carbohydrate and lipid metabolism, and the sustained expression of the antioxidative response mediated by NRF2. As a consequence, a reductive stress situation arises in the cell that inhibits the RICTOR pathway, thus activating the early stage of autophagy, impairing xenobiotic metabolism, and potentiating lipid biosynthesis and steatosis. PM exposure-induced hepato-proteostatic alterations were significantly reduced in Se supplemented mice, suggesting that the use of this trace element as a dietary supplement may at least partially ameliorate liver damage caused by exposure to environmental mixtures.

Bioaccumulation and molecular effects of carbamazepine and methylmercury co-exposure in males of Dreissena polymorpha

Dreissena polymorpha is a bivalve promising for biomonitoring in freshwater ecosystems thanks to its abundance and high filtration activity allowing rapid uptake of toxicants and identification of their negative effects. Nonetheless, we still lack knowledge on its molecular responses to stress under realistic scenario, e.g. multi-contamination. Carbamazepine (CBZ) and Hg are ubiquitous pollutants sharing molecular toxicity pathways, e.g. oxidative stress. A previous study in zebra mussels showed their co-exposure to cause more alterations than single exposures, but molecular toxicity pathways remained unidentified. D. polymorpha was exposed 24 h (T24) and 72 h (T72) to CBZ (6.1 ± 0.1 μg L-1), MeHg (430 ± 10 ng L-1) and the co-exposure (6.1 ± 0.1 μg L-1CBZ and 500 ± 10 ng L-1 MeHg) at concentrations representative of polluted areas (~10× EQS). RedOx system at the gene and enzyme level, the proteome and the metabolome were compared. The co-exposure resulted in 108 differential abundant proteins (DAPs), as well as 9 and 10 modulated metabolites at T24 and T72, respectively. The co-exposure specifically modulated DAPs and metabolites involved in neurotransmission, e.g. dopaminergic synapse and GABA. CBZ specifically modulated 46 DAPs involved in calcium signaling pathways and 7 amino acids at T24. MeHg specifically modulated 55 DAPs involved in the cytoskeleton remodeling and hypoxia-induced factor 1 pathway, without altering the metabolome. Single and co-exposures commonly modulated proteins and metabolites involved in energy and amino acid metabolisms, response to stress and development. Concomitantly, lipid peroxidation and antioxidant activities were unchanged, supporting that D. polymorpha tolerated experimental conditions. The co-exposure was confirmed to cause more alterations than single exposures. This was attributed to the combined toxicity of CBZ and MeHg. Altogether, this study underlined the necessity to better characterize molecular toxicity pathways of multi-contamination that are not predictable on responses to single exposures, to better anticipate adverse effects in biota and improve risk assessment.

Spirulina (Arthrospira maxima) mitigates the toxicity induced by a mixture of metal and NSAID in Xenopus laevis

Cadmium (Cd) is often detected in the environment due to its wide use in industry; also, NSAIDs are one of the most consumed pharmaceuticals, particularly diclofenac (DCF). Several studies have reported the presence of both contaminants in water bodies at concentrations ranging from ng L-1 to μg L-1; in addition, they have shown that they can induce oxidative stress in aquatic species and disturb signal transduction, cell proliferation, and intercellular communication, which could lead to teratogenesis. Spirulina has been consumed as a dietary supplement; its antioxidant, anti-inflammatory, neuroprotective, and nutritional properties are well documented. This work aimed to evaluate if Spirulina reduces the damage induced by Cd and DCF mixture in Xenopus laevis at early life stages. FETAX assay was carried out: 20 fertilized oocytes were exposed to seven different treatments on triplicate, control, Cd (24.5 μg L-1), DCF (149 μg L-1), Cd + DCF, Cd+DCF+Spirulina (2 mg L-1), Cd+DCF+Spirulina (4 mg L-1), Cd+DCF+Spirulina (10 mg L-1), malformations, mortality, and growth were evaluated after 96 h, also lipid peroxidation, superoxide dismutase and catalase activity were determined after 192 h. Cd increased DCF mortality, Cd and DCF mixture increased the incidence of malformations as well as oxidative damage; on the other hand, the results obtained show that Spirulina can be used to reduce the damage caused by the mixture of Cd and DCF since it promotes growth, reduce mortality, malformations, and oxidative stress in X. laevis.

Heavy metals and metalloid in aquatic invertebrates: A review of single/mixed forms, combination with other pollutants, and environmental factors

Heavy metals (HMs) and metalloid occur naturally and are found throughout the Earth's crust but they are discharged into aquatic environments at high concentrations by human activities, increasing heavy metal pollution. HMs can bioaccumulate in higher organisms through the food web and consequently affect humans. In an aquatic environment, various HMs mixtures can be present. Furthermore, HMs adsorb on other environmental pollutants, such as microplastics and persistent organic pollutants, causing a synergistic or antagonistic effect on aquatic organisms. Therefore, to understand the biological and physiological effects of HMs on aquatic organisms, it is important to evaluate the effects of exposure to combinations of complex HM mixtures and/or pollutants and other environmental factors. Aquatic invertebrates occupy an important niche in the aquatic food chain as the main energy link between higher and lower organisms. The distribution of heavy metals and the resulting toxic effects in aquatic invertebrates have been extensively studied, but few reports have dealt with the relationship between HMs, pollutants, and environmental factors in biological systems with regard to biological availability and toxicity. This review describes the overall properties of individual HM and their effects on aquatic invertebrates and comprehensively reviews physiological and biochemical endpoints in aquatic invertebrates depending on interactions among HMs, other pollutants, and environmental factors.

MCDA-DEA approach to construct a composite indicator for effluents from WWTPs considering the influence of PPCPs

Considering current water situation, reuse is an effective solution to meet water demand and reduce pressure on conventional water sources. However, pharmaceutical and personal care products (PPCPs) in effluents from wastewater treatment plants (WWTPs) decrease their quality and suitability. With the aim of identifying and monitoring both the influence of PPCPs and the suitability of effluents to be reused, this study proposes the development of a composite indicator (CI) related to PPCP presence in WWTPs, through the common weight multi-criteria decision analysis (MCDA)-data envelopment analysis (DEA) model. Obtaining a CI for PPCPs is a novel approach in the published literature, showing a new perspective in PPCP management and their influence in wastewater treatment. Furthermore, this study proposes an improvement on MCDA-DEA model which maintains the initial hierarchy obtained for the units analyzed. The development of CI is based on information about the technological, environmental, social, and biological issues of WWTPs. Results show that 4 of the 33 WWTPs analysed had the best CI values, meaning that their effluents have lower environmental impact. The development of a CI related to PPCPs in WWTPs suggests that further steps are needed to manage the WWTP effluents. Hence, the need to implement preventive measures in WWTPs has been shown, even though the removal of PPCPs is not yet part of European law. This work highlights the importance of considering PPCPs as priority pollutants in wastewater management and reuse frameworks, to guarantee low environmental impact and adapt wastewater reuse based on a circular economy approach. HIGHLIGHTS: Emerging contaminants (PPCPs) are used as effluent quality indicators. A composite indicator for PPCPs performance has been developed through MCDA-DEA model. Indicator obtained allow decision makers implementing concrete actions to assess effluent quality. Results show the improvement capacity of the effluents quality through PPCPs removing.

Pharmaceuticals in multi-media environment from the Jin River to adjacent marine embayment in Southeast China

Multi-media environmental distribution of 21 pharmaceuticals in river water, coastal water, groundwater and sediments from the Jin River to adjacent marine embayment, Southeast China, was reported for the first time. All the detected 10 pharmaceuticals were antibiotics. Oxytetracycline (OTC), ciprofloxacin (CFC) and enrofloxacin (EFC) were the most ubiquitous antibiotics and could be detected in all water samples. EFC also showed the highest detection frequency (100%) in both riverine and coastal sediments. The detected antibiotics were more widely distributed in coastal environment of Asia, especially China, rather than Europe, USA and Australia. Sulfamethoxazole (SMX) showed stronger sorption onto sediments compared with other antibiotics due to its higher pseudo-partitioning coefficients (846-10,786 L kg^-1). The discharged wastewater and aquaculture were the main sources of antibiotics in the multi-media environment. Risk assessment indicated that CFC and SMX posed high risks to Microcystis aeruginosa and Synechococcus leopolensis in river water, coastal water and groundwater.

The potential of algae and aquatic macrophytes in the pharmaceutical and personal care products (PPCPs) environmental removal: a review

The presence of emerging contaminants, such as pharmaceuticals and personal care products (PPCPs), in aquatic environments has received increasing attention in the last years due to the various possible impacts on the dynamics of the natural environment and human health. In global terms, around 771 active pharmaceutical substances or their transformation products have been detected at levels above their respective detection limit. Additionally, 528 different compounds have been detected in 159 countries. Seeking to overcome potential ecotoxicological problems, several studies have been conducted using different technologies for PPCPs removal. Recently, the use of macro, microalgae, and aquatic macrophytes has been highlighted due to the excellent bioremediation capacity of these organisms and easy acclimatization. Thus, the present review aims to outline a brief and well-oriented scenario concerning the knowledge about the bioremediation alternatives of PPCPs through the use of macro, microalgae, and aquatic macrophytes. The characteristics of PPCPs and the risks of these compounds to the environment and human health are also addressed. Moreover, the review indicates the opportunities and challenges for expanding the use of biotechnologies based on algae and aquatic macrophytes, such as studies dedicated to relate the operational criteria of these biotechnologies with the main PPCPs removal mechanisms. Finally, algae and macrophytes can compose green and ecological biotechnologies for wastewater treatment, having great contribution to PPCPs removal.

Are preserved coastal water bodies in Spanish Mediterranean basin impacted by human activity? Water quality evaluation using chemical and biological analyses

The Spanish Mediterranean basin is particularly susceptible to climate change and human activities, making it vulnerable to the influence of anthropogenic contaminants. Therefore, conducting comprehensive and exhaustive water quality assessment in relevant water bodies of this basin is pivotal. In this work, surface water samples from coastal lagoons or estuaries were collected across the Spanish Mediterranean coastline and subjected to target and suspect screening of 1,585 organic micropollutants by liquid chromatography coupled to ion mobility separation and high resolution mass spectrometry. In total, 91 organic micropollutants could be confirmed and 5 were tentatively identified, with pharmaceuticals and pesticides being the most prevalent groups of chemicals. Chemical analysis data was compared with data on bioanalysis of those samples (recurrent aryl hydrocarbon receptor (AhR) activation, and estrogenic receptor (ER) inhibition in wetland samples affected by wastewater streams). The number of identified organic contaminants containing aromatic rings could explain the AhR activation observed. For the ER antagonistic effects, predictions on estrogenic inhibition potency for the detected compounds were used to explain the activities observed. The integration of chemical analysis with bioanalytical observations allowed a comprehensive overview of the quality of the water bodies under study.

Metabolic, cellular and defense responses to single and co-exposure to carbamazepine and methylmercury in Dreissena polymorpha

Carbamazepine (CBZ) and Hg are widespread and persistent micropollutants in aquatic environments. Both pollutants are known to trigger similar toxicity mechanisms, e.g. reactive oxygen species (ROS) production. Here, their effects were assessed in the zebra mussel Dreissena polymorpha, frequently used as a freshwater model in ecotoxicology and biomonitoring. Single and co-exposures to CBZ (3.9 μg L^-1) and MeHg (280 ng L^-1) were performed for 1 and 7 days. Metabolomics analyses evidenced that the co-exposure was the most disturbing after 7 days, reducing the amount of 25 metabolites involved in protein synthesis, energy metabolism, antioxidant response and osmoregulation, and significantly altering cells and organelles' structure supporting a reduction of functions of gills and digestive glands. CBZ alone after 7 days decreased the amount of α-aminobutyric acid and had a moderate effect on the structure of mitochondria in digestive glands. MeHg alone had no effect on mussels' metabolome, but caused a significant alteration of cells and organelles' structure in gills and digestive glands. Single exposures and the co-exposure increased antioxidant responses vs control in gills and digestive glands, without resulting in lipid peroxidation, suggesting an increased ROS production caused by both pollutants. Data globally supported that a higher number of hyperactive cells compensated cellular alterations in the digestive gland of mussels exposed to CBZ or MeHg alone, while CBZ + MeHg co-exposure overwhelmed this compensation after 7 days. Those effects were unpredictable based on cellular responses to CBZ and MeHg alone, highlighting the need to consider molecular toxicity pathways for a better anticipation of effects of pollutants in biota in complex environmental conditions.

Biodiversity impacts by multiple anthropogenic stressors in Mediterranean coastal wetlands

Mediterranean coastal wetlands are considered biodiversity hot-spots and contain a high number of endemic species. The biodiversity of these ecosystems is endangered by several pressures resulting from agricultural and urban expansion, climate change, and the alteration of their hydrological cycle. In this study we assess the state-of-the-art regarding the impact of several stressor groups on the biodiversity of Mediterranean coastal wetlands (i.e., lagoons, marshes, estuaries). Particularly, we describe the impacts of eutrophication, chemical pollution, invasive species, salinization, and temperature rise, and analyze the existing literature regarding the impact of multiple stressors on these ecosystems. Our study denotes a clear asymmetry both in terms of study areas and stressors evaluated. The majority of studies focus on lagoons and estuaries of the north-west parts of the Mediterranean basin, while the African and the Asian coast have been less represented. Eutrophication and chemical pollution were the most studied stressors compared to others like temperature rise or species invasions. Most studies evaluating these stressors individually show direct or indirect effects on the biodiversity of primary producers and invertebrate communities, and changes in species dominance patterns that contribute to a decline of endemic populations. The few available studies addressing stressor interactions have shown non-additive responses, which are important to define appropriate ecosystem management and restoration measures. Finally, we propose research needs to advance our understanding on the impacts of anthropogenic stressors on Mediterranean coastal wetlands and to guide future interventions to protect biodiversity.

Corrosion of an AZ31B Magnesium Alloy by Sulfate-Reducing Prokaryotes in a Mudflat Environment

To study the abnormal failure of magnesium anodes for buried pipelines in marine engineering in the unique environment of mudflats, a strain of a sulfate–reducing prokaryote (SRP) was isolated from pipe–laying soil, and identified as Desulfovibrio sp. HQM3. Weight–loss test, electrochemical measurements, SEM, EDS, XRD, and CLSM techniques were used to study the effect of corrosion on the AZ31B magnesium alloy. Under the influence of SRP, the magnesium alloy corroded severely at rates up to 1.31 mm/year in the mudflat environment. SRP accelerated corrosion by 0.3mm/year. Pitting occurred on the samples in both abiotic and biotic systems. The pitting depth reached 163.47 μm in the biotic system after 14 days. The main composition of a petal–like corrosion product was Mg(OH)2. The results show that a mudflat environment can lead to an accelerated corrosion of magnesium alloys.

Eutrophication and sediment-water exchange of total petroleum hydrocarbons and heavy metals of Hashilan wetland, a national heritage in NW Iran

The heavy metal(loid)s concentrations in water and sediments were analyzed in the Hashilan wetland to assess the spatial distribution, pollution status, fate, partitioning, and ecological risk and also to identify the heavy metal(loid)s sources in sediments using PMF (Positive Matrix Factorization) and APCs-MLR (absolute principal component score-multiple linear regression) receptor models. According to the pollution indices, (Ni, Cu, Cr, Mo), and (Zn, Cr, and Cu) are considered the most important pollutants in sediments and water, respectively. Ni, Cr, and Cu are the main contributors to ecological risks in sediments of some stations. The potential ecological risk assessment proposed low ecological risk in water of the study area. Higher distribution coefficient (Kp) values of Ni, Cr, Mn, Cu, Co, Pb, As, and Zn indicated the majority of these heavy metals present in the sediments; whereas, the majority of Cd concentration occurs in water. PMF and APCs-MLR results indicated the natural sources were the main factors affecting the concentrations of Ni, Cr, Zn, Al, Co, Fe, Pb, As, Cd and somewhat Cu. Mixed natural and agricultural activities are the main sources of Mo, and somewhat Cu. According to the results, there is low pollution of TPH (total petroleum hydrocarbons) in the sediment samples. Also, phosphate (PO42-) and nitrate (NO3-) concentrations were below the recommended permissible limits at all sampling sites except the S8 station for NO3-.

Oxidative stress and metal homeostasis alterations in Danio rerio (zebrafish) under single and combined carbamazepine, acetamiprid and cadmium exposures

Contaminants of emerging concern (CEC) are routinely detected in aquatic environments, especially pharmaceuticals, such as carbamazepine (CBZ), and neonicotinoid pesticides, like acetamiprid (ACT). CECs can interact with each other and with other legislated contaminants like Cd, resulting in unknown effects. Most studies evaluate only the effects of single contaminant exposures on aquatic biota. Therefore, the aim of the present study was to assess the effects of both single and combined CBZ, ACT and Cd exposures on zebrafish brain and liver oxidative stress parameters and metal homeostasis. The biomarkers catalase (CAT), glutathione-S-transferase (GST), total thiols (TOT), metallothionein (MT) and malondialdehyde (MDA) and the essential elements Ca, Cu, K, Na, Mg, Mn and Zn were evaluated after 96-hour static exposures. CBZ, ACT and Cd single (brain and liver) and combined (liver) treatments resulted in oxidative effects in both fish organs, also leading to metal (Ca, Mg, K, Mn, Zn and Cu) homeostasis alterations. ACT exposure resulted in the greatest adverse effects in the brain, while CBZ was the cause of major element homeostasis and oxidative stress alterations in the liver. Lower LPO levels were observed in the combined treatments compared to single treatments, suggesting interactions and contaminant effect attenuation. This study is the first to evaluate the initial effects of combined CBZ, ACT and Cd exposures in zebrafish, paving the way for further investigations concerning other biomarkers during longer exposure times.

Presence of pharmaceuticals and their metabolites in wild-living aquatic organisms - Current state of knowledge

In the last decades an increasing number of studies has been published concerning contamination of aquatic ecosystems with pharmaceuticals. Yet, the distribution of these chemical compounds in aquatic environments raises many questions and uncertainties. Data on the presence of selected pharmaceuticals in the same water bodies varies significantly between different studies. Therefore, since early 1990 s, wild organisms have been used in research on environmental contamination with pharmaceuticals. Indeed, pharmaceutical levels measured in biological matrices may better reflect their overall presence in the aquatic environments as such levels include not only direct exposure of a given organisms to a specific pollutant but also processes such as bioaccumulation and biomagnification. In the present paper, data concerning occurrence of pharmaceuticals in aquatic biota was reviewed. So far, pharmaceuticals have been studied mainly in fish and molluscs, with only a few papers available on crustaceans and macroalgae. The most commonly found pharmaceuticals both in freshwater and marine organisms are antibiotics, antidepressants and NSAIDS while there is no information about the presence of anticancer drugs in aquatic organisms. Furthermore, only single studies were conducted in Africa and Australia. Hence, systematization of up-to-date knowledge, the main aim of this review, is needed for further research targeting.

Vulnerability assessment and management planning for the ecological environment in urban wetlands

As a special ecosystem in cities, urban wetland parks have important environmental regulation and social service functions. This paper proposes a new methodology of urban wetland planning and management based on the vulnerability of the ecological environment. The Jixi National Wetland Park (JNWP) was taken as the research area to analyze the ecological, geological and environmental factors that affect urban wetlands. A remote sensing image, digital elevation model, and environmental quality interpolation processing were used to generate the factor layer, and a comprehensive evaluation index system was established. The fuzzy Delphi analytic hierarchy process (FDAHP) method was used to calculate the comprehensive weight of each evaluation factor. A model to evaluate the ecological environment vulnerability of the JNWP was established. Then, an improved k-means clustering algorithm was used to classify the ecological environment of the study area. The ecological environment vulnerability of the wetland was evaluated. The results showed that the vulnerability of the ecological environment in the study area could be divided into five levels, including very low, low, medium, high and very high vulnerability areas. According to the vulnerability level and the results of k-means++ cluster analysis, the JNWP is divided into five areas. The wetland buffer zone is the main factor that determines the distribution of ecological environment vulnerability in urban wetlands. However, cultivated land development and ecological environmental restoration are the main factors that determine the evolution of ecological environment vulnerability in urban wetlands. The FDAHP and geographic information systems (GIS), combined with cluster analysis, are effective methods to evaluate the vulnerability of the ecological environment of urban wetlands, which provides a scientific and accurate methodology for the management and sustainable development of urban wetlands.

Spatial distribution, partitioning, ecological risk and source apportionment of potential toxic elements in water and sediments of the Hoor Al-Azim wetland and their bioaccumulation in selected commercial fish species

The potentially toxic elements (PTEs) concentrations in water and sediments were measured in the Hoor Al-Azim wetland to evaluate the spatial distribution, pollution rate, fate, partitioning, and ecological risk and also to recognize the PTEs sources in sediments using MLR-APCs (multiple linear regression-absolute principal component scores) receptor model. The human health risk was investigated based on the seven fish species consumed in the study area. Based on the results, water and sediment contamination was observed at some stations in the southern part of the wetland where agricultural water drains. Also, the sediments of oil well drilling disposal site was polluted by PTEs. Based on the MLR-APCs model, 80.8% of Mo and 81.5% of Se originated from agricultural source. Total target hazard quotients (TTHQ) values suggested that the children could experience adverse health effects due to consumption of Coptodon zillii, Aspius vorax, Carassius auratus and Carasobarbus luteus.

Pharmaceuticals and personal care products in a Mediterranean coastal wetland: Impact of anthropogenic and spatial factors and environmental risk assessment

The present study focused on the occurrence, distribution and risk assessment of 32 pharmaceuticals and personal care products (PPCPs) in water and sediment, as well as the surrounding soil of the irrigation channels and lake of a Mediterranean coastal wetland, the Albufera Natural Park (Valencia, Spain). Moreover, the influent and effluent of ten wastewater treatment plants (WWTPs) that treat wastewater from Valencia and the surrounding areas were also studied. BPA, caffeine, diclofenac, ethyl paraben, methyl paraben, metformin, tramadol and salicylic acid were the predominant PPCPs detected in the channels and the lake, and are in good agreement with those detected in the effluent. Furthermore, 22 PPCPs were detected in >47% of the sediment samples. Of them, BPA, ethyl paraben, furosemide, ibuprofen and salicylic acid were at higher concentrations. In contrast, only seven PPCPs were detected in >44% of the soil samples. Spatial variation showed that the concentration of many PPCPs was higher in the northern area of the park, whereas the ibuprofen concentrations were higher in the south. Differences were also observed according to the type of water used for irrigation and the land uses of the area. A risk assessment based on the hazardous quotient (HQ) indicated that caffeine is a compound of concern, and tramadol at the highest concentration showed a moderate risk for the organisms assessed. Considering the mixture of the PPCPs found at each sampling point, the green algae are at risk, particularly in those points located near the city of Valencia (the most important nearby human settlement). These results indicate the need for further studies.

Acclimatization of microbial community of submerged membrane bioreactor treating hospital wastewater

This study was performed to understand the dynamics of the microbial community of submerged membrane bioreactor during the acclimatization process to treat the hospital wastewater. In this regard, three acclimatization phases were examined using a mixture of synthetic wastewater (SWW) and real hospital wastewater (HWW) in the following proportions; In Phase 1: 75:25 v/v (SWW: HWW); Phase 2: 50:50 v/v (SWW: HWW); and Phase 3: 25:75 v/v (SWW: HWW) of wastewater. The microbial community was analyzed using Illumina high throughput sequencing to identify the bacterial and micro-eukaryotes community in SMBR. The acclimatization study clearly demonstrated that shift in microbial community composition with time. The dominance of pathogenic and degrading bacterial communities such as Mycobacterium, Pseudomonas, and Zoogloea was observed at the phase 3 of acclimatization. This study witnessed the major shift in the micro-eukaryotes community, and the proliferation of fungi Basidiomycota was observed in phase 3 of acclimatization.

Single and combined effects of carbamazepine and copper on nervous and antioxidant systems of zebrafish (Danio rerio)

Various pollutants co-exist in the aquatic environment such as carbamazepine (CBZ) and copper (Cu), which can cause complex effects on inhabiting organisms. The toxic impacts of the single substance have been studied extensively. However, the studies about their combined adverse impacts are not enough. In the present study, zebrafish were exposed to environmental relevant concentrations of CBZ (1, 10, and 100 μg/L), Cu (0.5, 5, and 10 μg/L) and the mixtures (1 μg/L CBZ + 0.5 μg/L Cu, 10 μg/L CBZ + 5 μg/L Cu, 100 μg/L CBZ + 10 μg/L Cu) for 45 days, the effects on nervous and antioxidant systems of zebrafish were investigated. The results demonstrated that, in comparison with single exposure group, the combined presence of CBZ and Cu exacerbated the effect of antioxidant system (the ability of inhibition of hydroxyl radicals (IHR), superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST)) but not nervous system (Acetylcholinesterase [AChE]). The qPCR results supported the changes of corresponding enzymes activities. Hepatic histopathological analysis verified the results of biomarkers. Our work illustrated that the toxicity of mixed pollutants is very complicated, which cannot simply be inferred from the toxicity of single pollutant, and calls for more co-exposure experiments to better understanding of the co-effects of pollutants on aquatic organisms.

Combined effects of environmentally relevant concentrations of diclofenac and cadmium on Chironomus riparius larvae

The nonsteroidal anti-inflammatory drug diclofenac (DCF) is considered a contaminant of emerging concern. DCF can co-exist with heavy metals in aquatic environments, causing unexpected risks to aquatic organisms. This study aimed to assess the combined effects of DCF and cadmium (Cd) at environmentally relevant concentrations on the bioconcentration and status of oxidative stress and detoxification in Chironomus riparius larvae. The larvae were exposed to DCF (2 and 20 μg L^-1) and Cd (5 and 50 μg L^-1) alone or in mixtures for 48 h. The combined exposure to DCF and Cd was found to reciprocally facilitate the accumulation of each compound in larvae compared with single exposures. As indicated by the antioxidant enzyme activities, reduced glutathione levels, and malondialdehyde contents, the low concentration of the mixture (2 μg L^-1 DCF + 5 μg L^-1 Cd) did not alter the oxidative stress status in larvae, while the high concentration of the mixture (20 μg L^-1 DCF + 50 μg L^-1 Cd) induced stronger oxidative damage to larvae compared with single exposures. The expression levels of eight genes (CuZnSOD, MnSOD, CAT, GSTd3, GSTe1, GSTs4, CYP4G, and CYP9AT2) significantly decreased due to the high concentration of the mixture compared with single exposures in most cases. Overall, the results suggest that the mixture of DCF and Cd might exert greater ecological risks to aquatic insects compared with their individual compounds.

Heavy metal pollution and the risk from tidal flat reclamation in coastal areas of Jiangsu, China

Tidal flat is an important supplementary land resource. However, increasing tidal flat reclamation in China has resulted in severe environmental issues. Using single-metal pollution index and multi-metal Nemerow pollution index, this study aimed to evaluate the risks of heavy metal pollution among different tidal flat use types, including fish farm, farmland, pastoral land, industrial land, forest and unutilized land. The results indicated that, concentrations of all elements were higher than geochemical values; Cd posed the highest risk, followed by As and Ni. Fish farm created the highest risk, followed by farmland. Every one year increase in fish farming led to increases in sediment concentrations of Cu, Cr, Ni, Pb, Zn and As by 0.73, 1.25, 0.68, 0.41, 1.22 and 0.20 mg.kg^-1, respectively. Tidal flat reclamation in Jiangsu Province creates the risk of heavy metal pollution, and specific attention should be paid to the fodders and additives used in fish farming.

Keystone taxa of water microbiome respond to environmental quality and predict water contamination

The human activity introduces strong environmental stresses, and results in great spatiotemporal heterogeneity for the environment. Although the effects of environmental factors on the microbial diversity and succession have been widely studied, knowledge about how keystone taxa respond to environmental stresses remains poorly understood. We examined bacterial and archaeal communities from 45 wetland ponds covering a wide range of waters in Hangzhou. We found that shifts in bacterial and archaeal communities were strongly correlated with water pollution as indicated by the comprehensive water quality identification (CWQI). The SEGMENTED analysis suggested that there were non-linear responses of microbial communities and keystone taxa to the water pollution gradient. Moreover, these significant tipping points (e.g., CWQI > 4.0) would afford a warning line for urban wetland management. Notably, keystone taxa of bacterial communities could be used to successfully (~88.9% accuracy) predict water contamination levels. This study provides new insights into the potential for keystone bacterial taxa to predict water contamination.

Effect of salinity on zinc toxicity (ZnCl2 and ZnO nanomaterials) in the mosquitofish (Gambusia sexradiata)

Zn is an essential trace metal in living beings. However, excessive concentrations can cause toxic effects even in the aquatic biota. Zn is widely used in different industrial sectors, which has increased its presence in aquatic environments. To assess the acute toxicity of Zn, bioassays were performed with the fish Gambusia sexradiata for a 96-h exposure using ZnCl₂ (0 and 15 salinity) and ZnO nanomaterials (0 salinity). The mean lethal concentrations (LC₅₀-96 h) for ZnCl₂ were 25.36 (19.64-32.76) and 177.91 (129.39-244.63) mg Zn L^-1 to 0 and 15 salinity, respectively. The increased concentration of ZnCl₂ showed a dose-response relationship; similarly, the increase in salinity significantly reduces the toxicity of Zn. Characterisation of ZnO nanomaterials was carried out by FTIR, DRX, SEM, DLS and zeta potential. The FTIR spectra showed the characteristic band of Zn-O vibration at 364 cm^-1, while DRX presents the hexagonal wurtzite structure with an average crystallite size of 40 nm. SEM micrographs reveal rod-like shapes with lengths and diameters of 40-350 nm and 90 nm, respectively. Agglomerates of 423 nm in water suspension were obtained by DLS and zeta potential of + 14.4 mV. Under these conditions, no mortality was observed due to the rapid flocculation/precipitation of ZnO nanomaterials, which involved brief interaction periods of Zn in the water column with the fish. Gambusia sexradiata is affected by increased Zn concentrations in hard water conditions, and salinity changes modified Zn toxicity, placing it as a suitable model for toxicity tests for this type of particles.

Separation of trace pharmaceuticals individually and in combination via forward osmosis

With a high rejection coefficient for trace pharmaceuticals and personal care products (PPCPs), forward osmosis (FO) membrane separation has become a cutting-edge technology in water treatment owing to its low energy consumption and low membrane fouling. Wastewater contains many types of PPCPs, and one pharmaceutical molecule affects the separation behaviors of other pharmaceuticals in FO. Therefore, simultaneous FO of multiple PPCPs needs to be investigated. In this study, the separation behaviors of four trace pharmaceuticals (ciprofloxacin (CIP), sulfamethoxazole (SMX), acetaminophen (ACP), carbamazepine (CBZ)), individually (termed "single pharmaceuticals") and in combination (termed "binary pharmaceuticals" as two pharmaceuticals were studied simultaneously), during FO were investigated at trace concentrations using ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The results showed that for single pharmaceuticals, the molecular sieve dominates their retention rate-the retention rate increases with increasing Stokes radius of the molecules (29.1 → 94.8% for 0.35 → 0.47 nm). For binary pharmaceuticals, the retention rates of both pharmaceuticals without charge decrease with increasing total molecule number (for ACP + CBZ, 31.4 → 52.1% (ACP), 75.1 → 83.0% (CBZ)). Negatively charged pharmaceuticals are mutually exclusive with the negatively charged FO membrane, resulting in the increase of the retention rate of pharmaceuticals (83.1 → 90.1% (CIP) when CIP + ACP → CIP + SMX). In the presence of a positively charged pharmaceutical, the retention rate of negatively charged pharmaceuticals decreases (85.7 → 80.4% (SMX) when SMX + ACP → SMX + CIP) because the positively charged pharmaceutical neutralizes the negative charge on the FO membrane surface, resulting in the weakening of electrostatic repulsion between the negatively charged pharmaceutical and FO membrane surface. The positively charged molecule attracts the negatively charged molecule, forming a couple of molecules with larger molecule weight and increasing the retention rate of the pharmaceuticals (80.4 → 88.2% (SMX) when pH = 7 → 5 for SMX + CIP). The results suggest that the interactions between pharmaceuticals cannot be ignored in the process of removing PPCPs by FO.

Multifunctional magnetic MgMn-oxide composite for efficient purification of Cd2+ and paracetamol pollution: Synergetic effect and stability

A multifunctional magnetic composite (0.3Ma-MgMnLDO-a) with the function of Cd²⁺ adsorption and paracetamol (PAM) degradation was successfully fabricated. Surface morphology showed that Fe₃O₄ agglomeration was overcome on composite. The composite had high specific surface area of 105.32 m² g^-1 and saturation magnetization of 40 emu∙g^-1. 0.3Ma-MgMnLDO-a could reach Cd²⁺ adsorption equilibrium within 5 min with 99 % removal rate. The maximum adsorption capacity was 3.76 mmol·g^-1 (422.62 mg g^-1), which apparently higher than that of Fe₃O₄-a and MgMnLDO-a, indicating that the Fe/Mn synergism results in excellent ability for Cd²⁺ adsorption. Moreover, the composite could efficiently activate peroxymonosulfate (PMS) to rapid degrade PAM with the highest first-order rate constants (k_obs = 0.116 min^-1) and total organic carbon (TOC) removal rate (67.7 %), which also due to the contribution of Fe/Mn synergism in PMS activation. The cycling of Mn^III/Mn^IV and Fe^II/Fe^III played an important role in activating PMS to generateO₂^-•, ¹O₂ and OH for degradation. The composite exhibited both stable adsorption and catalytic performance on wide pH (3-9) and five reuse cycles. Notably, there was mutual promotion between Cd²⁺ and PAM adsorption, while the coexistence of Cd²⁺ had slight inhibition on PAM degradation. Overall, the magnetic composite had promising application for purifying heavy metals and pharmaceuticals.

Interactive effects of diclofenac and copper on bioconcentration and multiple biomarkers in crucian carp (Carassius auratus)

Diclofenac (DCF), a non-steroidal anti-inflammatory drug, is widespread in aquatic environments and coexists with heavy metals to form combined pollution. However, the interactive effects of DCF and heavy metals on aquatic organisms remain unknown. This study aimed to investigate the interactive effects of DCF and copper (Cu) on the bioconcentration, oxidative stress status and detoxification-related gene expression in crucian carp (Carassius auratus). Fish were exposed to Cu (100 μg L^-1) and DCF (1, 10, 100 and 1000 μg L^-1) alone or in combination for 7 days. Results obtained showed that the treatment of Cu combined with high levels of DCF (100 and 1000 μg L^-1) significantly decreased tissue concentrations of DCF and Cu compared to the correspondingly individual exposure. Concerning oxidative stress status, as reflected by the activities of antioxidant enzymes and malondialdehyde content, low exposure concentrations of DCF (1 and 10 μg L^-1) seemed to mitigate the oxidative stress induced by Cu, whereas the co-exposure of Cu with the highest level of DCF (1000 μg L^-1) led to stronger oxidative damage in fish liver than Cu exposure alone. With regarding to detoxification-related genes, in most cases, the expressions of cyp 1a, cyp 3a, gstα, gstπ, pxr and P-gp in crucian carp were significantly altered upon exposure to the compounds in combination compared to exposure to the compounds individually. Collectively, these findings indicate the capacity of each of these pollutants to alter bioconcentration potential, pro-oxidative effects and detoxification-related gene responses of the other when both co-occur at specific concentrations.

Carbamazepine, cadmium chloride and polybrominated diphenyl ether-47, synergistically modulate the expression of antioxidants and cell cycle biomarkers, in the marine fish cell line SAF-1

A wide range of contaminants, industrial by-products, plastics, and pharmaceutics belonging to various categories, have been found in sea water. Although these compounds are detected at concentrations that might be considered as sub-lethal, under certain conditions they could act synergistically producing unexpected effects in term of toxicity or perturbation of biochemical markers leading to standard pathway. In this study, the Sparus aurata fibroblast cell line SAF-1, was exposed to increasing concentrations of carbamazepine (CBZ), polybrominated diphenyl ether 47 (BDE-47) and cadmium chloride (CdCl₂) until 72 h, to evaluate the cytotoxicity and the expression of genes related to antioxidant defense, cell cycle and energetic balance. In general, both vitality and gene expression were affected by the exposure to the different toxicants, in terms of antioxidant defense and cell cycle control, showing the most significant effects in cells exposed to the mixture of the three compounds, respect to the single compounds separately. The synergic effect of the compounds on the analyzed biomarkers, underlie the potential negative impact of the contaminants on health of marine organisms.

Enhancement of ciprofloxacin degradation in aqueous system by heterogeneous catalytic ozonation

Fluoroquinolones are extensively used in medicine due to their antimicrobial activity. Their presence in water inhibits microorganism activity in conventional wastewater treatment plants. This study aims to evaluate the technical feasibility of applying heterogeneous catalytic ozonation to eliminate ciprofloxacin (CIP) as a representative of fluoroquinolone antibiotics normally present in municipal wastewater discharges. Experiments were conducted in a semi-batch stirred slurry reactor, using 0.7 L of 100 mg L^-1 CIP aqueous solution, at pH 3 and 30 °C. Experimental results show that single ozonation can easily oxidise CIP molecules (68%) within the first 5 min, leading to the generation of refractory oxidation by-products. However, when heterogeneous catalytic ozonation is applied using iron oxide supported on MFI synthetic zeolite, total degradation of CIP is observed at 5 min and a higher mineralisation rate is obtained. A novel sequential process is developed for CIP mineralisation. In a first step, a flash single ozonation is applied and CIP molecules are broken down. Then, a catalytic ozonation step is conducted by adding the Fe/MFI catalyst into the reactor. As a result of catalyst addition, 44% of Total Organic Carbon (TOC) is eliminated within the first 15 min, compared to single ozonation where only 13% of TOC removal is reached in the same time. The application of this sequential process to a real wastewater effluent spiked with CIP leads to 52% of TOC removal.

Stability of antibiotics in drinking water: An advanced approach towards the impacts of water quality parameters on doxycycline bioavailability

Objective:

This study was considered to explore the possible impacts of drinking water quality from different sources on the bioavailability of doxycycline.

Materials and Methods:

Sixty-four tap and ground drinking water samples collected from poultry farms were scrutinized for their water quality limits (TH, pH, total dissolved solids, electrical conductivity, Cl⁻, Ca⁺², Na⁺, and Mg⁺²) and heavy metals concentrations (Zn, Fe, Cu, and Ni). An in vitro study was conducted by adding the therapeutic concentrations of doxycycline to all tested water samples, and allowed to interact for 1 h, 3 h, 5 h, and 8 h followed by re-estimation of doxycycline concentrations after each contact time using thin layer chromatography.

Results:

The therapeutic concentration of doxycycline was decreased in tap water samples by 1.92%, 9.63%, 22.42%, and 30.83% for the aforementioned contact times, respectively, while the corresponding reduction percentages in ground water samples were 2.14%, 17.14%, 28.57%, and 40.09%. However, the control samples had never showed any recorded decrease in their doxycycline concentrations overall contact times. All measured concentrations of doxycycline were significantly lower in tap and ground water than those of control at all times of contact. Both pH, Mg⁺² showed significant positive correlations with decreasing values of doxycycline in water.

Conclusion:

Different drinking water sources reduce the concentrations of doxycycline in vitro in a time dependent manner, which can be attributed to their different physico-chemical parameters, i.e., pH and Mg⁺² ions. This emphasizes the role of water quality on the stability of antibiotics concentrations administrated via drinking water.

Development and Validation of an Analytical Method for the Detection and Quantification of Bromazepam, Clonazepam and Diazepam by UPLC-MS/MS in Surface Water

The development of analytical methods capable of determining micropollutants is essential for quality control of drinking water. Benzodiazepines, a class of pharmaceuticals with anxiolytic properties, have received increasing attention as micropollutants. The purpose of this study was to develop an analytical method for determination of three benzodiazepine drugs (bromazepam, clonazepam and diazepam) in surface water. For the extraction of the matrix analytes, SPE cartridges (C18, 500 mg/3 mL) were used. The method was validated according to the quality criteria of the USEPA 8000D Validation Guide. The developed and validated method showed recovery values between 57 and 100%, RSD < 20% and R² > 0.9949. LD ranged between 2.70 and 5.00 ng L^-1 for bromazepam and clonazepam respectively whereas LQ was 0.01 μg L^-1 for all analytes. The matrix affected the signal intensity of clonazepam thus evidencing the matrix effect by analysis statistic (F test).

The dynamics of the pharmaceutical and personal care product interactive capacity under the effect of artificial enrichment of soil with heavy metals and of wastewater reuse

A greenhouse experiment was conducted, using a randomized block design, including twelve heavy metal (Mn, Zn, Cu, Cd, Co, Cr, Ni, Pb) mixture treatments, with each metal participating in the treatment with 0, 2, 4, 6, 8, 10, and 12 mg/kg, respectively. Common beet (Beta vulgaris L.) was chosen as test plant. The plants were irrigated with treated municipal wastewater taken from the Wastewater Treatment Plant of the town of Amaliada, N.W., Peloponnese, Greece. The experiment aimed at studying the interactions between heavy metals and macro-microelements, and pharmaceuticals and personal care products (PPCPs). The basic scope was to shed some light on the potential environmental implications, of these interactions on the soil PPCPs for a more effective monitoring of these emerging contaminants in the plants and soil continuum. It was found that the PPCPs have a very high potential interactive capacity, having interacted with all the studied metals, and metalloids, as well as with plant macro elements (P, and K). The uptake of PPCPs by plants was statistically significantly related with their respective content in the soil. The general inference is that the interactive relations between heavy metals, macro-, microelements, and emerging contaminants, being mainly antagonistic, which contribute to the decrease the uptake of soil PPCPs.

Oxidative stress in the galaxiid fish, Galaxias maculatus, exposed to binary waterborne mixtures of the pro-oxidant cadmium and the anti-oxidant diclofenac

Chemical mixtures represent environmentally-realistic exposures of contaminants to aquatic biota. However, there remains a limited understanding of how toxicant mixtures may impact biological function, relative to their individual components. In the current study, oxidative stress responses of the freshwater galaxiid fish inanga (Galaxias maculatus) were examined following exposure to the pro-oxidant trace metal cadmium (2 or 9 μg L^-1), and the anti-oxidant pharmaceutical drug diclofenac (770 μg L^-1), individually or in simple binary mixtures. Cadmium exposure in the absence of diclofenac significantly decreased renal catalase activity, increased hepatic catalase activity, decreased renal superoxide dismutase (SOD) and decreased glutathione-S-transferase activity, effects that are suggestive of anti-oxidant defense inhibition and/or generation of increased reactive oxygen species. Diclofenac exposure in the absence of cadmium resulted in a decreased renal lipid peroxidation, consistent with its known anti-oxidant properties. The presence of waterborne diclofenac altered the effects of cadmium on catalase activity in the liver, SOD activity in the gill, and lipid peroxidation in the liver. Co-exposure with cadmium modulated diclofenac effects on lipid peroxidation in the kidney. These data indicate the capacity of each of these toxicants to offset biological effects of the other when both co-occur in urban waters at specific concentrations. This study also demonstrates the complexity of outcomes in contaminant mixtures, even when these stressors are presented as simple binary combinations.

Ecotoxicological Effect of Single and Combined Exposure of Carbamazepine and Cadmium on Female Danio rerio: A Multibiomarker Study

In aquatic environments, organisms are exposed to mixtures of pollutants which may change the toxicity profile of each contaminant, compared to its toxicity alone. Carbamazepine (CBZ) and cadmium (Cd) are among the pollutants that co-occur in aquatic environments. To date, most research about their toxicity towards aquatic vertebrates is based on single exposure experiments. The present study aims to evaluate single and combined effects of CBZ and Cd on biomarkers in female Danio rerio (zebrafish) by exposing them to environmentally relevant concentrations of these two pollutants for ten days. Four kinds of biomarkers involved in antioxidant systems, energy metabolism, nervous system, and endocrine disruption, respectively, were studied. Our research results coincided with those of former studies in single exposure experiments. However, the combined exposure of CBZ and Cd exerted different responses from other studies in which these two contaminants were examined alone in zebrafish. The present study evidenced the need to conduct more coexposure studies to enhance the environmental relevance of these experimental results.

Optimization of ciprofloxacin degradation in wastewater by homogeneous sono-Fenton process at high frequency

Emerging pollutants such as pharmaceuticals have been focusing international attention for a few decades. Ciprofloxacin (CIP) is a common drug that is widely found in hospital and wastewater treatment plants effluents, as well as in rivers. In this work, the feasibility of CIP degradation by ultrasound process at high frequency is discussed and sonolysis, sonolysis with hydrogen peroxide and sono-Fenton are evaluated. The amounts of hydrogen peroxide and ferrous ions (Fe²⁺) needed were optimized using response surface methodology. Best results were obtained with the sono-Fenton process resulting in a total pharmaceutical degradation within 15 min and a mineralization greater than 60% after 1 h. Optimal conditions were tested on a real matrix from a municipal wastewater treatment plant. Even if the degradation of the pollutants by sono-Fenton was hampered, the removal efficiency of both CIP and total organic carbon (TOC) is interesting as an increase in the biodegradability of the wastewater is found. These results show that sono-Fenton oxidation can be a promising pretreatment process for pharmaceutical-containing wastewaters.

Heavy metals and arsenic content in water along the southern Caspian coasts in Iran

Due to the importance of pollution monitoring in marine ecosystems and lack of a coherent and systematic investigation of heavy metal ions along the southern shores of the Caspian Sea, in the present study, the amount of these metals and As ions in coastal waters along its 780-km-long coast in Iran have been studied. Heavy metals (cobalt, nickel, copper, zinc, cadmium, mercury, lead) and a poisonous metalloid (arsenic) were selected in 59 sampling stations and determined using differential pulse polarography method. The multivariate statistical tools were applied to describe and interpret the experimental data. The overall mean concentrations of studied metals (in microgram per liter; μg L^-1) in the samples were found in the order Zn (10.9) > Ni (7.4) > Cu (5.5) > Pb (1.9) > Hg (1.4) > As (1.3) > Co (1.1) > Cd (0.2). The results when compared with reported international standards confirmed that the sampled waters do contain some of these elements above the suggested maximum permissible limits. Hg and Cu were detected in 54.2 and 72.9% of the samples, almost all above the permissible limits. Ni, Zn, Pb, and Co were detected in 100, 96.6, 93.2, and 88.1%, respectively, while 8.5, 22.0, 3.4, and 1.7% were above the permissible limits. Cd and As were present in 61 and 93% of the samples, and their concentrations were higher than the rate presented by Russian System of Management Chemicals (RSMC). In addition, spatial distribution of heavy metal concentrations showed that Gorgan Bay is an ecosystem serving as a filter, trapping natural and anthropogenic materials that are brought from industrial, commercial, and urbanized areas. The multivariate data analysis reveals that Caspian Sea is contaminated by both anthropogenic as well as pedo-geochemical sources.

Monetary valuation of salicylic acid, methylparaben and THCOOH in a Mediterranean coastal wetland through the shadow prices methodology

The presence of pharmaceutical and personal care products and drugs of abuse (PPCPs) in wastewater treatment plants (WWTPs) indicates discharge of the effluent may not be suitable for the ecological balance of water ecosystems, such as wetlands. These PPCPs degrade water quality, considered as an ecosystem service (ES), provoking serious environmental impacts. Assessing the monetary value of PPCPs can be used as a proxy for environmental status of the ES of water quality (ESWQ). Considering PPCPs as non-desirable outputs of WWTPs, the shadow prices methodology has been implemented using directional distance function to measure the environmental avoided cost of removing salicylic acid (SA), methylparaben (MP), and THCOOH from WWTPs effluents discharged to Albufera Natural Park (Spain). The SA shows the highest shadow price (138.16 €/μg), followed by THCOOH (48.15 €/μg), and MP (30.66 €/μg). These values are interpreted as the environmental cost that would be avoided if SA, MP, and THCOOH were removed from WWTPs effluents. The non-parametric tests show that wastewater treatment technology, together with population equivalent (as a proxy of the size of urban areas) and seasonality are factors that influence shadow prices obtained. The approach used in this study highlights the use of PPCPs as status indicators of ESWQ quantified in monetary units. As a way to synthesize the essential concepts to implement the shadow prices approach, this study proposes a flow diagram to represent the relationship between all the factors involved in this work. The use of shadow prices methodology proves that removing SA, MP, and THCOOH is associated with a measurable improvement in the ESWQ of Albufera Natural Park. The findings of this study will be useful for plant managers in order to make decisions about the removal of PPCPs in WWTPs effluents.

Diclofenac in the marine environment: A review of its occurrence and effects

Interest in the presence and effects of diclofenac (DCF) and other pharmaceutical products (PPs) in the aquatic environment has been growing over the last 20 years. DCF has been included in the First Watch List of the EU Water Framework Directive in order to gather monitoring data in surface waters. Despite PP input in water bodies, few studies have been conducted to determine the extent of DCF occurrence and effects on marine ecosystems, which is usually the final recipient of surface waters. The present article reviews available published data on DCF occurrence in marine water, sediment and organisms, and its effects on marine organisms. The findings highlight the scarcity of available data on the occurrence and effects of DCF in marine ecosystems, and the need for further data acquisition to assess the risks associated with the presence of this compound in the environment.

Effects of single and combined exposure of pharmaceutical drugs (carbamazepine and cetirizine) and a metal (cadmium) on the biochemical responses of R. philippinarum

In the aquatic environment, organisms are exposed to complex mixtures of contaminants which may alter the toxicity profile of each compound, compared to its toxicity alone. Pharmaceutical drugs (e.g. carbamazepine (CBZ) and cetirizine (CTZ)) and metals (e.g. cadmium (Cd)) are among those contaminants that co-occur in the environment. However, most studies concerning their toxicity towards aquatic species are based on single exposure experiments. Thus, the present study aimed to evaluate single and combined effects of Cd and CBZ or CTZ (single conditions: Cd, CTZ, CBZ; combined conditions: CTZ + Cd, CBZ + Cd) on biomarkers related to oxidative stress and energy metabolism in the edible clam Ruditapes philippinarum, by exposing the organisms for 28 days to environmentally relevant concentrations of these contaminants. The biomarkers studied were: i) the electron transport system activity, protein and glycogen contents (indicators of organisms' metabolic status and energy reserves); ii) lipid peroxidation and the ratio between reduced and oxidized glutathione (indicators of oxidative stress); iii) superoxide dismutase and catalase activities (enzymes indicators of antioxidant defence) and iv) activity of glutathione S-transferases (family of enzymes indicators of biotransformation capacity). Results obtained showed that the uptake of Cd and CBZ was not affected by the combined presence of the contaminants. However, for CTZ, the uptake was higher in the presence than in the absence of Cd. Concerning toxicity data, in general, the combined exposures (CTZ + Cd, CBZ + Cd) had lower biological effects than the contaminants alone. Nevertheless, our data showed that despite the low concentrations tested, they were enough to exert biological effects that differed between single and combined treatments, evidencing the need to conduct more co-exposure studies to increase the environmental relevance of the gathered data.

Potential export of soluble reactive phosphorus from a coastal wetland in a cold-temperate lagoon system: Buffer capacities of macrophytes and impact on phytoplankton

The main pathways for phosphorus flux from land to sea are particle-associated (erosion) and dissolved runoff (rivers, groundwater, and agricultural drainage systems). These pathways can act as diffused sources for aquatic systems and support primary production, therefore, counteracting the efforts aimed at reducing phosphorus input from point sources such as sewage treatment plants. Phosphorus supports primary production in the water column and can elevate phytoplankton and macrophyte growth. Coastal wetlands with emerged (Phragmites australis) and submerged (Stuckenia pectinata and Chara sp.) macrophytes can affect phosphorus fluxes in the land-water transitional zone. The macrophytes have the potential to act as a buffer for phosphorus run-off. The aim of this study was to determine the phosphorus stocks in the transitional land-sea zone of a cold temperate lagoon at the southern Baltic Sea. Phosphorus in macrophytes, water samples, and phytoplankton growth were analyzed along a gradient moving away from the wetland. The phosphorus stocks in the above ground biomass of the Phragmites plants were the highest at the end of August and with more than 8000mgPm^-2 in the interior zone of the wetland, threefold the amount of P in Phragmites plant tissue at the wetland fringe. The submerged macrophytes stored only 300mgPm^-2, close to the wetland. Concentrations of soluble reactive phosphorus in the water column were higher in the zones of emerged macrophytes than in the zones of submerged macrophytes and decreased along the land-sea transect. Phytoplankton could grow proximal to the wetland during all seasons, but not further away. This study indicates that macrophytes can act as phosphorus sinks. However, short-term releases of phosphate within the Phragmites wetland have the potential to lead to phytoplankton growth. Phytoplankton can use these nutrient pulses either immediately or later, and support high biomass and turbidity within the system.

Effects of ibuprofen and carbamazepine on the ion transport system and fatty acid metabolism of temperature conditioned juveniles of Solea senegalensis

The increasing presence of pharmaceuticals in aquatic environments in the last decades, derived from human and veterinary use, has become an important environmental problem. Previous studies have shown that ibuprofen (IB) and carbamazepine (CBZ) modify physiological and biochemical processes in Senegalese sole (Solea senegalensis) in a temperature-dependent manner. In other vertebrates, there is evidence that both of these pharmaceuticals interfere with the 'arachidonic acid (AA) cascade', which is responsible for the biosynthesis of numerous enzymes that are involved in the osmoregulatory process. The present work aims to study the temperature-dependent effects of these two pharmaceuticals on several biochemical and molecular parameters in Senegalese sole. Regarding osmoregulation, Na⁺, K⁺ -ATPase enzyme activity was determined in the gills, kidney and intestine, and the expressions of both Na⁺, K⁺ -ATPase 1α-subunit isoforms (ATP1A1a and ATP1A1b) were quantified in gills. Gill prostaglandin-endoperoxide synthase-2 (PTGS2) gene expression and fatty acid composition were selected to determine the interference of both pharmaceuticals with the AA cascade. Senegalese sole juveniles, acclimatised at 15°C or 20°C, were exposed through intraperitoneal injection to IB (10mg/kg) and CBZ (1mg/kg) for 48h. Non-injected fish (Control) and those injected with the carrier (sunflower oil; S.O.), acclimated at each of the two temperatures, were used for comparison. The results show that IB directly affected the osmoregulatory mechanisms that alter gill and intestine Na⁺, K⁺ -ATPase activities. In addition, the copy number of ATP1A1a was higher at 20°C than at 15°C, which could be a direct response to the temperature variation. The gene expression of PTGS2 was affected by neither drug administration nor acclimation temperature. Nevertheless, detailed analysis of AA and eicosapentaenoic acid (EPA) percentages revealed a CBZ-derived effect in the fatty acid composition of the gills.