Ecotoxicological impact of the antihypertensive valsartan on earthworms, extracellular enzymes and soil bacterial communities

Effects of sulfamethazine and tetracycline at molecular, cellular and tissue levels in Eisenia fetida earthworms

Soil contamination by antibiotics is a global issue of great concern that contributes to the rise of bacterial antibiotic resistance and can have toxic effects on non-target organisms. This study evaluated the variations of molecular, cellular, and histological parameters in Eisenia fetida earthworms exposed to sulfamethazine (SMZ) and tetracycline (TC), two antibiotics commonly found in agricultural soils. The earthworms were exposed for 14 days to a series of concentrations (0, 10, 100, and 1000 mg/kg) of both antibiotics. SMZ and TC did not affect the survival of E. fetida, however, other effects at different levels of biological complexity were detected. The two highest concentrations of SMZ reduced the viability of coelomocytes. At the highest TC concentration, there was a noticeable decline in cell viability, acetylcholinesterase activity (neurotoxicity), and the relative presence of mucopolysaccharides in the epidermis (mucous production). Glutathione S-transferase activity decreased in all TC treatments and at the highest SMZ concentration. However, levels of malondialdehyde and protein carbonyls did not change, suggesting an absence of oxidative stress. Tetracycline was neurotoxic to E. fetida and changed the integrity of the epidermis. Both antibiotics altered the intestinal microbiota of E. fetida, leading to a reduction in the relative abundance of bacteria from the phyla Proteobacteria and Bacteroidetes, while causing an increase in the phylum Actinobacteroidota. All observed changes indicate that both SMZ and TC can disrupt the earthworms' immune system and gut microbiome, while fostering the growth of bacteria that harbour antibiotic resistance genes. Finally, both antibiotics exerted additional metabolic and physiological effects that increased the vulnerability of E. fetida to pathogens.

Synergistic biochar and Serratia marcescens tackle toxic metal contamination: A multifaceted machine learning approach

Metal contamination in soil poses environmental and health risks requiring effective remediation strategies. This study introduces an innovative approach of synergistically employing biochar and bacterial inoculum of Serratia marcescens to address toxic metal (TM) contamination. Physicochemical, enzymatic, and microbial analyses were conducted, employing integrated biomarker response (IBR) and machine-learning approaches for toxicity estimation. The combined application significantly reduced the Cd, Cr, and Pb concentrations by 71.6, 31.2, and 57.1%, respectively, while the Cu concentration increased by 85% in the individual Serratia marcescens treatment. Biochar enhanced microbial biomass by 33-44% after 25 days. Noteworthy physicochemical improvements included a 44.7% increase in organic content and a decrease in pH and electrical conductivity. The K⁺ and Ca2⁺ concentrations increased by 196.9 and 21.6%, respectively, while the Mg2⁺ content decreased by 86.4%. Network analysis revealed intricate relationships, displaying direct and indirect negative correlations between metals and soil physicochemical parameters. The IBR index values indicated effective mitigation of TM toxicity in Serratia marcescens and biochar with individual and combined treatments. Binary classification demonstrated high sensitivity (80.1%) and specificity (80.5%) in identifying TM-contaminated soil. These findings indicate significant biochar- and Serratia marcescens-induced impacts on toxic metal availability, physicochemical properties, and enzymatic activities in metal-contaminated soil, suggesting that blending soil with biochar and microorganisms is an effective remediation strategy.

Non-target analysis of Danish wastewater treatment plant effluent: Statistical analysis of chemical fingerprinting as a step toward a future monitoring tool

In an attempt to discover and characterize the plethora of xenobiotic substances, this study investigates chemical compounds released into the environment with wastewater effluents. A novel non-targeted screening methodology based on ultra-high resolution Orbitrap mass spectrometry and nanoflow ultra-high performance liquid chromatography together with a newly optimized data-processing pipeline were applied to effluent samples from two state-of-the-art and one small wastewater treatment facility. In total, 785 molecular structures were obtained, of which 38 were identified as single compounds, while 480 structures were identified at a putative level. Most of these substances were therapeutics and drugs, present as parent compounds and metabolites. Using R packages Phyloseq and MetacodeR, originally developed for bioinformatics, significant differences in xenobiotic presence in the wastewater effluents between the three sites were demonstrated.

Earthworms alleviate microplastics stress on soil microbial and protist communities

Microplastic (MP) pollution can exert significant pressure on soil ecosystems, however, the interactive effects of MPs on soil bacterial, fungal and protist communities remains poorly understood. Soil macrofauna, such as earthworms, can be directly affected by MPs, potentially leading to a range of feedbacks on the soil microbial community. To address this, we conducted a microcosm experiment to examine the effects of conventional (i.e., polyethylene, polystyrene) and biodegradable MPs (i.e. PBAT, polylactic acid) on the structure of the soil bacterial, fungal, and protist communities in the presence or absence of earthworms. We found that MP contamination negatively affected the diversity and composition of soil microbial and protist communities, with smaller-sized conventional MPs having the most pronounced effects. For example, compared with the unamended control, small-sized polyethylene MPs both significantly reduced the Shannon diversity of soil bacteria, fungi, and protist by 4.3 %, 37.0 %, and 9.1 %, respectively. Biodegradable MPs increased negative correlations among bacteria, fungi, and protists. However, earthworms mitigated these effects, enhancing the diversity and altering the composition of these communities. They also increased the niche width and stability of the soil microbial food web network. Our study indicated that earthworms help attenuate the response of soil microorganisms to MPs stress by influencing the diversity and composition of soil microorganisms and soil physicochemical properties and underscores the importance of considering macrofauna in MPs research.

Mixtures of environmental pharmaceuticals in marine organisms: Mechanistic evidence of carbamazepine and valsartan effects on Mytilus galloprovincialis

Unravelling the adverse outcomes of pharmaceuticals mixture represents a research priority to characterize the risk for marine ecosystems. The present study investigated, for the first time, the interactions between two of the most largely detected pharmaceuticals in marine species: carbamazepine (CBZ) and valsartan (VAL), elucidating mechanisms that can modulate bioaccumulation, excretion and the onset of toxicity. Mytilus galloprovincialis were exposed to environmental levels of CBZ and VAL dosed alone or in combination: measurement of drug bioaccumulation was integrated with changes in the whole transcriptome and responsiveness of various biochemical and cellular biomarkers. Interactive and competing mechanisms between tested drugs were revealed by the much higher CBZ accumulation in mussels exposed to this compound alone, while an opposite trend was observed for VAL. A complex network of responses was observed as variations of gene expression, functional effects on neurotransmission, cell cycle, immune responses and redox homeostasis. The elaboration of results through a quantitative Weight of Evidence model summarized a greater biological reactivity of CBZ compared to VAL and antagonistic interactions between these compounds, resulting in a reduced effect of the antiepileptic when combined with valsartan. Overall, new perspectives are highlighted for a more comprehensive risk assessment of environmental mixtures of pharmaceuticals.

A nationwide survey on the endosulfan residues in Chinese cotton field soil: Occurrence, trend, and ecological risk

The nationwide occurrence of endosulfan residues in cotton fields has not yet been investigated. Therefore, in this study, 202 surface soil samples from 27 cities were collected from cotton fields in 8 major cotton-planting provinces of China, covering more than 97% of the national cotton sown area. The results showed that endosulfan residues were detected in cotton fields throughout the country. The main type of residue found was endosulfan sulfate (ES-sulfate), followed by β-endosulfan and α-endosulfan, with average concentrations of 0.475, 0.129, and 0.048 μg/kg, respectively. Significant spatial variations in the endosulfan residues was noted, and the highest concentration of endosulfan residues was observed in the northwest inland cotton-growing area, followed by that in the Yellow River basin and Yangtze River basin cotton-growing areas. The endosulfan residues showed significant positive correlations with soil organic matter and soil clay contents. The α/β endosulfan ratio was determined to be in the range of 0.02-1.20, indicating that endosulfan residues originated from the endosulfan application performed in historical cotton cultivation efforts. Together with the literature data, the concentrations of α-endosulfan and β-endosulfan residues peaked in 2015 and 2017, respectively, and showed an overall decreasing trend from 2002 to 2021. The results of the ecological risk assessment suggested that Folsomia candida was most sensitive to endosulfan residues, with 20.8% of the sites presenting a high risk. However, in general, the soil ecological risk of cotton fields across the country was low. Our study demonstrated that China has achieved promising results in controlling the use and pollution of endosulfan, especially after 2014.

Commonwealth of Soil Health: How Do Earthworms Modify the Soil Microbial Responses to CeO2 Nanoparticles?

Soil ecotoxicological assays on nanoparticles (NPs) have mainly investigated single components (e.g., plants, fauna, and microbes) within the ecosystem, neglecting possible effects resulting from the disturbance of the interactions between these components. Here, we investigated soil microbial responses to CeO₂ NPs in the presence and absence of earthworms from the perspectives of microbial functions (i.e., enzyme activities), the community structure, and soil metabolite profiles. Exposure to CeO₂ NPs (50, 500 mg/kg) alone decreased the activities of enzymes (i.e., acid protease and acid phosphatase) participating in soil N and P cycles, while the presence of earthworms ameliorated these inhibitory effects. After the CeO₂ NP exposure, the earthworms significantly altered the relative abundance of some microbes associated with the soil N and P cycles (Flavobacterium, Pedobacter, Streptomyces, Bacillus, Bacteroidota, Actinobacteria, and Firmicutes). This was consistent with the pattern found in the significantly changed metabolites which were also involved in the microbial N and P metabolism. Both CeO₂ NPs and earthworms changed the soil bacterial community and soil metabolite profiles. Larger alterations of soil bacteria and metabolites were found under CeO₂ NP exposure with earthworms. Overall, our study indicates that the top-down control of earthworms can drastically modify the microbial responses to CeO₂ NPs from all studied biological aspects. This clearly shows the importance of the holistic consideration of all soil ecological components to assess the environmental risks of NPs to soil health.

Assessment of a wide array of organic micropollutants of emerging concern in wastewater treatment plants in Greece: Occurrence, removals, mass loading and potential risks

Exploring the contamination profile of multi-class emerging contaminants (ECs) in wastewater is highly desirable. To this end, the occurrence, removal, mass loading and risks associated with a large panel of pharmaceuticals and personal care products, illicit drugs, perfluorinated compounds and organophosphate flame retardants in two wastewater treatment plants (WWTPs) in the region of Thessaloniki (Greece) after a survey is illustrated. Influent and effluent wastewaters were submitted to solid phase extraction on Oasis HLB cartridges, followed by ultra-high-performance liquid chromatography Orbitrap high-resolution mass spectrometry (UHPLC-Orbitrap MS). Influent concentrations in both WWTPs were notably higher than effluent, with caffeine, acetaminophen, irbesartan and valsartan being the most ubiquitous compounds, exhibiting elevated concentrations. Average effluent concentrations ranged from below the method quantification limits (<MQL) to remarkably high values (μg L^-1 scale), such as for caffeine, acetaminophen, diclofenac, irbesartan and valsartan, among others. Removal efficiencies ranged between -273% for lamotrigine and 100%, i.e., for the UV filter BP1. Notably, the polar compounds such as cytarabine, methotrexate and capecitabine were removed at a rate >80% in both WWTPs, allowing the correlation between logK_ow and removals. Interesting trends for the illicit drugs were revealed by means of mass loading estimation, as in the case of benzoylecgonine (71.6 mg/day/1000 inhabitants). Ecotoxicological risk assessment was evaluated for both single components and mixture, using three approaches: risk quotient (RQ), risk quotient considering frequency (RQ_f) and toxic units (TU). Irbesartan and telmisartan posed a high risk in all trophic levels, while fish was the most sensitive taxa for diclofenac. This work aspires to intensify the surveillance programs for the receiving water bodies, as well as to motivate the investigation of toxicity to non-target organisms.

Biomonitoring of surface water quality in the Chopim River within the Conservation Unit Campos de Palmas Wildlife Refuge, southern Brazil

The Campos de Palmas Wildlife Refuge (RVS-CP) is a full protection conservation unit (CU) formed by private properties. The present study aimed to use the bioindicators Allium cepa L. (cytotoxicity and mutagenicity tests) and Eisenia fetida (avoidance test) to assess the quality of surface water of the Chopim River within the RVS-CP area and its surroundings during the four seasons of the year. To do so, water samples were collected at five points, four inside the RVS-CP area and a fifth point outside thereof. Samples from all sampling points had cytotoxic effect on A. cepa in at least one season of the year. Such a finding may be related to inadequate management practices (without land-use control) in the areas surrounding the sampling points such as forestry, native fields, pastures, agriculture, and housing areas. As for the animal bioindicator (E. fetida), only points 1 (in the winter) and 5 (in the autumn) were toxic. Concerning mutagenicity, points 1 and 4 (in the spring), 1 and 2 (in the summer), and 3 (in the autumn) showed mutagenic effect on A. cepa meristematic cells, therefore only within the RVS-CP area. Overall, these results show that biomonitoring can be an ally of the residents of the RVS-CP area in controlling management practices, aiming to bring together economic support and conservation of resources, especially water.

Ecotoxicological risk assessment of wastewater irrigation on soil microorganisms: Fate and impact of wastewater-borne micropollutants in lettuce-soil system

The implementation of the new Water Reuse regulation in the European Union brings to the forefront the need to evaluate the risks of using wastewater for crop irrigation. Here, a two-tier ecotoxicological risk assessment was performed to evaluate the fate of wastewater-borne micropollutants in soil and their ecotoxicological impact on plants and soil microorganisms. To this end, two successive cultivation campaigns of lettuces were irrigated with wastewater (at agronomical dose (not spiked) and spiked with a mixture of 14 pharmaceuticals at 10 and 100 µg/L each) in a controlled greenhouse experiment. Over the two cultivation campaigns, an accumulation of PPCPs was observed in soil microcosms irrigated with wastewater spiked with 100 μg/L of PPCPs with the highest concentrations detected for clarithromycin, hydrochlorothiazide, citalopram, climbazole and carbamazepine. The abundance of bacterial and fungal communities remained stable over the two cultivation campaigns and was not affected by any of the irrigation regimes applied. Similarly, no changes were observed in the abundance of ammonium oxidizing archaea (AOA) and bacteria (AOB), nor in clade A of commamox no matter the cultivation campaign or the irrigation regime considered. Only a slight increase was detected in clade B of commamox bacteria after the second cultivation campaign. Sulfamethoxazole-resistant and -degrading bacteria were not impacted either. The irrigation regimes had only a limited effect on the bacterial evenness. However, in response to wastewater irrigation the structure of soil bacterial community significantly changed the relative abundance of Acidobacteria, Chloroflexi, Verrucomicrobia, Beta-, Gamma- and Deltaprotebacteria. Twenty-eight operational taxonomic units (OTUs) were identified as responsible for the changes observed within the bacterial communities of soils irrigated with wastewater or with water. Interestingly, the relative abundance of these OTUs was similar in soils irrigated with either spiked or non-spiked irrigation solutions. This indicates that under both agronomical and worst-case scenario the mixture of fourteen PPCPs had no effect on soil bacterial community.

Environmental impacts of COVID-19 treatment: Toxicological evaluation of azithromycin and hydroxychloroquine in adult zebrafish

One of the most impact issues in recent years refers to the COVID-19 pandemic, the consequences of which thousands of deaths recorded worldwide, are still inferior understood. Its impacts on the environment and aquatic biota constitute a fertile field of investigation. Thus, to predict the impact of the indiscriminate use of azithromycin (AZT) and hydroxychloroquine (HCQ) in this pandemic context, we aim to assess their toxicological risks when isolated or in combination, using zebrafish (Danio rerio) as a model system. In summary, we observed that 72 h of exposure to AZT and HCQ (alone or in binary combination, both at 2.5 μg/L) induced the reduction of total protein levels, accompanied by increased levels of thiobarbituric acid reactive substances, hydrogen peroxide, reactive oxygen species and nitrite, suggesting a REDOX imbalance and possible oxidative stress. Molecular docking analysis further supported this data by demonstrating a strong affinity of AZT and HCQ with their potential antioxidant targets (catalase and superoxide dismutase). In the protein-protein interaction network analysis, AZT showed a putative interaction with different cytochrome P450 molecules, while HCQ demonstrated interaction with caspase-3. The functional enrichment analysis also demonstrated diverse biological processes and molecular mechanisms related to the maintenance of REDOX homeostasis. Moreover, we also demonstrated an increase in the AChE activity followed by a reduction in the neuromasts of the head when zebrafish were exposed to the mixture AZT + HCQ. These data suggest a neurotoxic effect of the drugs. Altogether, our study demonstrated that short exposure to AZT, HCQ or their mixture induced physiological alterations in adult zebrafish. These effects can compromise the health of these animals, suggesting that the increase of AZT and HCQ due to COVID-19 pandemic can negatively impact freshwater ecosystems.

Biomarker responses and metabolism in Lumbricus terrestris exposed to drugs of environmental concern, an in vivo and in vitro approach

The earthworm Lumbricus terrestris is an anecic species living in natural soils but it is also a sentinel in pollution monitoring. Specimens of L.terrestris were exposed for 48 h though the filter paper contact test at 1 mg/mL of the chemicals: Lamotrigine (LMG), Cocaine (COC), Fipronil (FIP) and the pesticide bis-4-nitrophenyl phosphate (BNPP). After that period, the activities of Acetylcholinesterase, Glutathione S-transferase, Carboxylesterase (CE) using different substrates, and lipid peroxidation levels were evaluated in the exposed whole tissue earthworms. The results revealed differences only in CE activity, with 4-nitrophenyl butyrate (4NPB) and 1-naphthyl butyrate (1NB) the most responsive substrates to COC. The kinetic parameters of CE were characterized, for the first time, in whole tissue of this species. The chemical analysis by LC-MS/MS, confirmed the exposure to the parent compounds, identified metabolites and evidenced biotransformation pathways in earthworms. Metabolic reactions included oxidation (LMG and FIP), hydrolysis (COC and FIP) as well as glycosylation (LMG, COC and FIP). A hitherto unknown metabolite of LMG due to the conjugation with phenylalanine glutamine was formed. The in vivo results on CE activity with the specific inhibitor, BNPP, were confirmed in vitro. Moreover, in the in vitro approach, the inclusion of other contaminants of environmental concern supports the potential of CE as biomarker. This study identifies the main metabolites formed by earthworms for further in vivo exposures under more realistic conditions and the potential use of CE measures as biomarker of emerging contaminants.