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14 pages, 6082 KiB

Open AccessArticle

Research Progress on Migratory Water Birds: Indicators of Heavy Metal Pollution in Inland Wetland Resources of Punjab, Pakistan

by Shifa Shaffique, Sang-Mo Kang, Muhammad Ahsan Ashraf, Ali Umar, Muhammad Saleem Khan, Muhammad Wajid, Abdullah Ahmed Al-Ghamdi and In-Jung Lee

Water 2024, 16(8), 1163; https://doi.org/10.3390/w16081163 - 19 Apr 2024

Viewed by 364

Abstract

The heavy metal burden on natural freshwater ecosystems is uninterruptedly increasing, which could affect their biodiversity, particularly regarding avian species. Three river barrages were selected for the sampling of water birds from autumn 2021 to spring 2022. Seven heavy metals—nickel (Ni), copper (Cu), [...] Read more.

The heavy metal burden on natural freshwater ecosystems is uninterruptedly increasing, which could affect their biodiversity, particularly regarding avian species. Three river barrages were selected for the sampling of water birds from autumn 2021 to spring 2022. Seven heavy metals—nickel (Ni), copper (Cu), cobalt (Co), zinc (Zn), lead (Pb), cadmium (Cd), and manganese (Mn)—were estimated in the hearts and livers of Fulica atra (Common Coot), Anas strepera (Gad-wall), and Anas crecca (Eurasian Teal) (Linnaeus, 1758) by atomic absorption spectrometry. The mean concentrations of metals were found to be significantly (p < 0.05) different among the sam-pling sites, species, and tissues. In the livers of F. atra and A. strepera, respectively, the highest mean concentration among the metals belonged to Zn (521 µg/g), and the lowest belonged to Cd (0.17 µg/g). The concentrations of Zn, Cu, Pb, Cd, and Co were highest in A. strepera heart samples. However, the concentrations of Zn, Pb, Cd, and Mn were found to be highest in the livers of F. atra. A comparison between both tissues indicated that the concentration of Ni is significantly (p < 0.05) higher (except for F. atra from Trimmu barrage) in the livers of water birds and that the concentration of Cd is significantly higher in the hearts of water birds. The mean metal concentrations were higher than the background limits reported in various studies, suggesting that the wintering water birds of Pakistan are under a significant load of heavy metal pollution. Histopathological analysis suggested that the observed heavy metals altered the normal histologies of hearts and livers of Fulica atra (Common Coot), Anas strepera (Gadwall), and Anas crecca (Eurasian Teal) sampled from three wetlands of Punjab Pakistan. Full article

(This article belongs to the Special Issue Toxic Pollutants in Water: Health Risk Assessment and Removal)

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15 pages, 2595 KiB

Open AccessArticle

Evaluating the Ecological Impact of Wastewater Discharges on Microbial and Contaminant Dynamics in Rivers

by Wenjie Jing, Shahdev Sajnani, Mengting Zhou, Hongfei Zhu and Ya Xu

Water 2024, 16(3), 377; https://doi.org/10.3390/w16030377 - 23 Jan 2024

Viewed by 1118

Abstract

This study focused on assessing the impact of pollutants discharged from the Fuxin Meng Wastewater Treatment Plant (FMWWTP) on the microbial communities in the Xi River; specific comparison between upstream and downstream regions was made. Water samples were obtained by mixing morning, midday, [...] Read more.

This study focused on assessing the impact of pollutants discharged from the Fuxin Meng Wastewater Treatment Plant (FMWWTP) on the microbial communities in the Xi River; specific comparison between upstream and downstream regions was made. Water samples were obtained by mixing morning, midday, and evening sampling at two points: one upstream and one downstream, each 500 m from the FMWWTP outfall. Utilizing metagenomic sequencing in conjunction with measured conventional physical and chemical properties, the research aimed to elucidate differences in microbial community structure, metabolic functions, potential biological contamination, and antibiotic resistance gene prevalence. The findings indicated a notable decrease in microbial diversity downstream compared to upstream; this was influenced primarily by the effluent from FMWWTP. This disparity in microbial diversity was evident at various taxonomic levels, with downstream samples showing higher diversity at the phylum level than at the genus level. Furthermore, downstream microbial populations demonstrated a broader range of metabolic and functional genetic diversity. Interestingly, the abundance of metabolic systems was generally greater downstream, with the notable exception of energy metabolism. This could be attributed to the stress imposed on downstream microorganisms by organic chemicals discharged from the treatment plant, and this prompts an enhanced metabolic decomposition function. The study also uncovered significant levels of potential biological contamination and antibiotic resistance gene pollution. This was more pronounced downstream of FMWWTP. In conclusion, discharge from FMWWTP has a substantial impact on the microbial communities of the Xi River, and this underscores the urgent need to optimize wastewater treatment processes to better comply with environmental quality standards. Full article

(This article belongs to the Special Issue Toxic Pollutants in Water: Health Risk Assessment and Removal)

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14 pages, 2014 KiB

Open AccessArticle

The First Evidence of the Water Bioremediation Potential of Ficopomatus enigmaticus (Fauvel 1923): From Threat to Resource?

by Manuela Piccardo, Verdiana Vellani, Serena Anselmi, Tecla Bentivoglio, Francesca Provenza, Monia Renzi and Stanislao Bevilacqua

Water 2024, 16(3), 368; https://doi.org/10.3390/w16030368 - 23 Jan 2024

Viewed by 1096

Abstract

Each year, a staggering 700,000 tons of synthetic dyes are manufactured globally, leading to the release of dye-laden wastewater into aquatic systems. These synthetic dyes resist biodegradation, endangering human and environmental health. Since traditional wastewater treatments are basically unable to remove dyes, exploring [...] Read more.

Each year, a staggering 700,000 tons of synthetic dyes are manufactured globally, leading to the release of dye-laden wastewater into aquatic systems. These synthetic dyes resist biodegradation, endangering human and environmental health. Since traditional wastewater treatments are basically unable to remove dyes, exploring the potential of alternative solutions, such as bioremediation, is crucial to reduce dye contamination in aquatic ecosystems. Ficopomatus enigmaticus (Fauvel 1923), listed as one of the 100 worst invasive species in Europe, is considered an invasive ecosystem engineer capable of causing economic and ecological losses. Despite this negative status, the literature suggests its positive contributions to aquatic ecosystems as habitat former and water bioremediator. However, existing evidence on the potential of F. enigmaticus to improve water quality is fragmented and lacks experimental data from laboratory tests. This study examined the potential of Ficopomatus reefs, both living and dead, to enhance water quality by removing contaminants, focusing on methylene blue (MB), one of the most common synthetic dyes. Bioaccumulation and bioadsorption were identified as key mechanisms for dye removal, supported by ATR-FTIR and microscopic analyses. Ficopomatus efficiently removed up to 80% of MB within 24 h. Bioaccumulation in the soft body accounted for 18% of the total removal, while complex adsorption phenomena involving carbonaceous, microalgal, and organic reef components accounted for 82%. Surprisingly, bioremediated solutions exhibited significant effects in ecotoxicological tests on bacteria, indicating the potential of F. enigmaticus to disrupt bacterial quorum sensing related to biofilm formation, and suggesting a possible antifouling action. This study underscores the intricate interplay between F. enigmaticus, water quality improvement, and potential ecological consequences, stressing the need for further investigation into its multifaceted role in aquatic ecosystems. Full article

(This article belongs to the Special Issue Toxic Pollutants in Water: Health Risk Assessment and Removal)

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22 pages, 8990 KiB

Open AccessArticle

ZnO-CuO Nanocomposite as an Efficient Adsorbent for As(III) Removal from Water

by Jesús Plácido Medina Salas, Francisco Gamarra Gómez, Elisban Juani Sacari Sacari, Wilson Orlando Lanchipa Ramos, Rocío María Tamayo Calderón, Efracio Mamani Flores, Víctor Yapuchura Platero, Walter Dimas Florez Ponce de León and Elmer Marcial Limache Sandoval

Water 2023, 15(24), 4318; https://doi.org/10.3390/w15244318 - 18 Dec 2023

Cited by 1 | Viewed by 1087

Abstract

Arsenic (III) exposure, often from contaminated water, can have severe health repercussions. Chronic exposure to this toxic compound is linked to increased risks of various health issues. Various technologies exist for arsenic (III) removal from contaminated water sources. This work synthesized ZnO-CuO nanocomposites [...] Read more.

Arsenic (III) exposure, often from contaminated water, can have severe health repercussions. Chronic exposure to this toxic compound is linked to increased risks of various health issues. Various technologies exist for arsenic (III) removal from contaminated water sources. This work synthesized ZnO-CuO nanocomposites through ultrasound-assisted coprecipitation, generating abundant hydroxylated sites via the deposition of ZnO nanoparticles onto CuO sheets for enhanced arsenic (III) adsorption. Structural characterization verified the formation of phase-pure heterostructures with emergent properties. Batch studies demonstrated exceptional 85.63% As(III) removal at pH 5, where binding with prevalent neutral H₃AsO₃ occurred through inner-sphere complexation with protonated groups. However, competing anions decreased removal through site blocking. Favorable pseudo-second order chemisorption kinetics and the 64.77 mg/g maximum Langmuir capacity revealed rapid multilayer uptake, enabled by intrinsic synergies upon nanoscale mixing of Zn/Cu oxides. The straightforward, energy-efficient ultrasonic production route makes this material promising for real-world water treatment integration. Full article

(This article belongs to the Special Issue Toxic Pollutants in Water: Health Risk Assessment and Removal)

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17 pages, 3674 KiB

Open AccessArticle

Control of Bromate Formation in Desalinated Seawater Production and Transmission with Ammoniation

by Ali A. Alhamzah, Abdulrahman S. Alofi, Abdulrahman A. Abid and Christopher M. Fellows

Water 2023, 15(21), 3858; https://doi.org/10.3390/w15213858 - 06 Nov 2023

Viewed by 1240

Abstract

Bromate is a potentially carcinogenic disinfection by-product of potential concern in desalinated waters, where bromide derived from seawater can be converted to bromate by the oxidising species used for disinfection. Historically, it has been difficult to maintain complete adherence to national standards of [...] Read more.

Bromate is a potentially carcinogenic disinfection by-product of potential concern in desalinated waters, where bromide derived from seawater can be converted to bromate by the oxidising species used for disinfection. Historically, it has been difficult to maintain complete adherence to national standards of no more than 10 ppb for bromate at all locations served with desalinated seawater by the Saline Water Conversion Corporation (SWCC) in the Kingdom of Saudi Arabia. In this full-scale study, the addition of 100–200 ppb of ammonia to the produced water of a Multi-Stage Flash Desalination plant effectively controlled the formation of bromate in the transmission system supplying inland centres in the Makkah Province of the Kingdom of Saudi Arabia (Arafa, Taif) on a time scale sufficient for the distribution of water to the consumer, even when the bromide content of the produced water was artificially enhanced (up to 132 ppb) via the addition of seawater. Full article

(This article belongs to the Special Issue Toxic Pollutants in Water: Health Risk Assessment and Removal)

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15 pages, 1934 KiB

Open AccessArticle

Cyanide Bioremediation by Bacillus subtilis under Alkaline Conditions

by César Julio Cáceda Quiroz, Gabriela de Lourdes Fora Quispe, Milena Carpio Mamani, Gisela July Maraza Choque and Elisban Juani Sacari Sacari

Water 2023, 15(20), 3645; https://doi.org/10.3390/w15203645 - 18 Oct 2023

Cited by 1 | Viewed by 1962

Abstract

Cyanide (CN) is a toxic environmental pollutant generated by various industrial activities, necessitating the application of bioremediation techniques for its degradation. Biodegradation is a more cost-effective and environmentally friendly technique with high efficiency in CN removal. This study isolated cyanide-degrading bacteria from Tutupaca [...] Read more.

Cyanide (CN) is a toxic environmental pollutant generated by various industrial activities, necessitating the application of bioremediation techniques for its degradation. Biodegradation is a more cost-effective and environmentally friendly technique with high efficiency in CN removal. This study isolated cyanide-degrading bacteria from Tutupaca mining site soil from Tacna, Peru. Bacillus subtilis strain TT10s was selected for its exceptional capacity to rapidly and completely eliminate cyanide under alkaline conditions (pH 10.5), removing 1000 ppm cyanide within 48 h. A kinetic analysis revealed that the biodegradation follows second-order rate kinetics (k₂ = 0.08649 mg/(mg·h), R² = 0.96622), consistent with the literature attribution of the rate-limiting step to the inducible cyanide dihydratase enzyme, which converts cyanide into ammonia and formate via the Michaelis–Menten model. Fourier-transform infrared spectroscopy (FTIR) spectral analysis further corroborated this enzymatic mechanism, showing the disappearance of CN peaks coupled with the emergence of ammonia (NH) and formate (C=O) peaks. Quantitative kinetic modelling integrated with FTIR profiles and degradation curves implicates cyanide dihydratase as the key rate-controlling enzyme in alkaline cyanide biodegradation without the need for an extra carbon source, generating interest for future bioremediation applications in highly contaminated environments. Full article

(This article belongs to the Special Issue Toxic Pollutants in Water: Health Risk Assessment and Removal)

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12 pages, 1294 KiB

Open AccessArticle

Redox Behavior of Chromium in the Reduction, Coagulation, and Biotic Filtration (RCbF) Drinking Water Treatment—A Pilot Study

by Daniel Mahringer, Sami S. Zerelli and Aki S. Ruhl

Water 2023, 15(19), 3363; https://doi.org/10.3390/w15193363 - 25 Sep 2023

Viewed by 933

Abstract

The chromium (Cr) limit values are currently tightened to 25 μg L⁻¹ (EU), 5 μg L⁻¹ (Germany), and possibly 10 μg L⁻¹ Cr(VI) (California). The combined process of chemical reduction, coagulation, and biotic filtration (RCbF) efficiently removes Cr(VI) in drinking [...] Read more.

The chromium (Cr) limit values are currently tightened to 25 μg L⁻¹ (EU), 5 μg L⁻¹ (Germany), and possibly 10 μg L⁻¹ Cr(VI) (California). The combined process of chemical reduction, coagulation, and biotic filtration (RCbF) efficiently removes Cr(VI) in drinking water. In this study, redox-active substances (O₂, NO₃⁻, Fe²⁺, MnO₂) were investigated concerning their effect on the RCbF process. The experiments were performed at two-stage pilot waterworks for biological iron and manganese removal. O₂ or NO₃⁻ as oxidants affected the RCbF process, neither by consumption of the reductant Fe(II) nor by re-oxidation of already formed Cr(III) in the supernatant of the filter bed. However, the oxidation of Cr(III) by O₂ to Cr(VI) with MnO₂ as a mediator was identified as potential risk for Cr breakthrough. Up to one third of the initial Cr(III) concentration was oxidized to Cr(VI) in the second filter bed within a contact time of only 5 min. The kinetically relevant mechanism seemed to be the formation of Cr(III)Fe(III)-hydroxides and not the reduction of Cr(VI) by Fe(II). Further, the mixing of Cr(VI) containing raw water with Fe(II) containing groundwater was determined as a chemical-free alternative for the RCbF process, depending on the resulting Fe(II) concentration after mixing. Full article

(This article belongs to the Special Issue Toxic Pollutants in Water: Health Risk Assessment and Removal)

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Review

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17 pages, 1363 KiB

Open AccessReview

Sustainable Utilization of Pulp and Paper Wastewater

by Xiaoli Liang, Yanpeng Xu, Liang Yin, Ruiming Wang, Piwu Li, Junqing Wang and Kaiquan Liu

Water 2023, 15(23), 4135; https://doi.org/10.3390/w15234135 - 29 Nov 2023

Cited by 2 | Viewed by 2868

Abstract

The pulp and paper industry plays an important role in the global economy and is inextricably linked to human life. Due to its large scale, the production process generates a large amount of wastewater, which poses a major threat to the environment. The [...] Read more.

The pulp and paper industry plays an important role in the global economy and is inextricably linked to human life. Due to its large scale, the production process generates a large amount of wastewater, which poses a major threat to the environment. The sustainable utilization and safe treatment of pulp and paper wastewater can effectively reduce environmental pollution, improve resource utilization efficiency, protect water resources, provide economic benefits for pulp and paper enterprises, and thus promote the green and sustainable development of the pulp and paper industry. Therefore, this study discusses the pollution components of pulp and paper wastewater and their impact on the environment and human health. In this review, we aim to explore the sustainable development of pulp and paper wastewater by summarizing the characteristics of current pulp and paper wastewater, the commonly used treatment methods for pulp and paper wastewater, the application of pulp and paper wastewater recycling, and the future development direction of pulp and paper wastewater. Full article

(This article belongs to the Special Issue Toxic Pollutants in Water: Health Risk Assessment and Removal)

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