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Riverine sediments are important reservoirs of heavy metals, representing both historical and contemporary anthropogenic activity within the watershed. This review has been conducted to examine the distribution of heavy metals in the surface sediment of 52 riverine systems from various Asian and European countries, as well as to determine their sources and environmental risks. The results revealed significant variability in heavy metal contamination in the world's riverine systems, with certain hotspots exhibiting concentrations that exceeded the permissible limits set by environmental quality standards. Among the studied countries, India has the highest levels of chromium (Cr), cobalt (Co), manganese (Mn), nickel (Ni), zinc (Zn), cadmium (Cd), copper (Cu), and lead (Pb) contamination in its riverine systems, followed by Iran > Turkey > Spain > Vietnam > Pakistan > Malaysia > Taiwan > China > Nigeria > Bangladesh > Japan. Heavy metal pollution in the world's riverine systems was quantified using pollution evaluation indices. The Contamination Factor (CF) revealed moderate contamination (1 ≤ CF < 3) throughout the geological units, with the exception of Pb, Cd, and Cu. The Contamination Degree (CD) classifies the contamination level into different categories: Low degree of contamination (CD < 6), moderate degree of contamination (6 ≤ CD < 12), considerable degree of contamination (12 ≤ CD < 24), and a very high degree of contamination (CD ≥ 24), while the Pollution Load Index (PLI) estimate the total amount of heavy metal pollution in riverine sediments, with Turkey having the highest PLI value of 6.512, followed by Spain, Vietnam, Taiwan, Pakistan, Bangladesh, China, India, Japan, Malaysia, Iran, and Nigeria. In applied multivariate statistics, correlation analysis determined the fate and distribution of heavy metals in riverine systems, while Principal Component Analysis (PCA) elucidated the potential sources, including industrial, agrochemical, mining, and domestic wastewater discharges, lubricant leakages, multiple geogenic inputs, erosion of mafic and ultramafic rocks, and minimal atmospheric deposition. As per Potential Ecological Risk Index (PERI) perspectives, Vietnam, Spain, and Turkey have the highest ecological risk, followed by Nigeria > Pakistan > Bangladesh > China > Taiwan > Japan and Iron, while the potential risks of ∑non-carcinogenic Pb, Cr, Ni, Cu, Cd, Co, Zn, and Mn for exposed human children and adults through ingestion and dermal contact were significantly influenced between acceptable to high risk, necessitating special attention from pollution control agencies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Microplastic had been commonly used in personal care products (PCPs) until it was documented to be a pollutant. The relative contents of microplastics in PCPs decrease in the order of the USA, Europe, and Asia. The geometric means of the abundance and mass of microplastics found in PCPs were 2162 particles/g and 0.04 g/g, respectively. Diameters of PCP-derived microplastics are less than 350 μm. To quantify the exact contribution of PCPs to microplastic pollution, this review surveyed the existing scientific literature and statistically integrated the findings from 88 literatures. Overall, approximately 1500 tons/year of microplastics from PCPs escape from WWTPs and enter the global aquatic environment. According to the PCP consumption and microplastics levels, the mass emission of global PCP-derived microplastics reach up to 1.2 × 10 4 tons/year. The two figures account for ~0.1% and ~ 0.8% of the annual global release of primary microplastics in the world oceans (~1.5 × 10 6 tons/year). In the last 50 years (1970-2019), up to 3.00 × 10 5 tons of PCP-derived microplastics have accumulated in the environment. The main plastic in PCPs is polyethylene, which is known for being a remarkably resistant polymer to degradation. Even if microbeads are completely banned globally in 2020, microplastics that have been discharged into the environment will still persist for a long time and claim our highest attention. This review provided primary information to deal effectively with the problem of PCP-derived microplastic both now and in the future., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Plastic is widely used for human activities (food packaging, medical, technological devices, etc.) and there is a growing concern regarding the risks for environmental and human health because they have still not been fully evaluated. Particularly, microplastics (primary and secondary) are present in all environmental compartments and this poses a potential threat because of their entry into the food chain. Furthermore, microplastics can absorb numerous pollutants that can be accumulated in the human body through bioaccumulation and biomagnification processes. We carried out a systematic review using a PRISMA approach to verify the efficiency of wastewater treatment plants (WWTPs) for microplastic removal. The international databases (PubMed, Science Direct, Scopus) were used to find published studies on efficiency of wastewater treatment plants (WWTPs) for microplastic removal. The search period was between January 2010 and June 2020. Over 1000 full research papers were initially selected through the use of keywords. After that, the papers were further selected by English language, title, and abstract, and duplicate papers and non-relevant papers were eliminated according to eligibility criteria. Finally, we included 15 full research papers. In each of the 15 full research papers selected, the microplastics identified were categorized by the authors for shape, size, and type of polymers identified. The characterization of the various types of microplastics was performed by Fourier Transform Infrared Spectroscopy (FTIR) or Raman spectroscopy. We have observed how wastewater treatments plants located in different continents (Europe, Asia, North America) mostly use a primary and secondary type of treatment that allows one to reach a high percentage of microplastics removal from wastewater. Most of the wastewater treatments plants investigated reported a microplastics removal efficiency greater than 90%, but despite this, millions of microplastics continue to be released every day into the aquatic environment. Then, in the near future, efficient and common standardized protocols for monitoring MPs should be drawn up, as well as increasing the knowledge of sources and strategies to further reduce microplastics contamination of treated wastewater.

Chromium is a controversial element, since it has been classified as essential trace element, to chemically and biologically inert compound, to potent intoxicator. Concerns have been risen for chromium effects on human and aquatic life because chromium has been accused for genotoxicity and carcinogenesis. Metals and their ions or complexes (and thus chromium substances) are included in the indicative list of main pollutants (Annex VIII of the Water Framework Directive (2000/60/EC)). Biological effects of chromium are strongly depended on chromium speciation. No universal Cr III or Cr VI discharge limits to the aquatic environment have been suggested by the EU. International bodies within the EU, such as the Helsinki Commission and the Oslo-Paris Convention, have issued recommendations on chromium discharge levels. National Cr VI and Cr III discharge limits vary in each EU Member State with respect to the receiving water body (marine water, lake, river, sewer system). The maximum discharge limit to the aquatic environment in EU is 1 and 5 mg L -1 for Cr VI and Cr total , respectively. The present work summarizes EU legislation, with respect to the discharge limits to the aquatic environment for Cr VI and Cr III . EU national limits that are currently effective are presented and compared to the limits in other parts of the world, such as Australia, Asia, USA, Latin America and South Africa. It is wise that future perspective of chromium policy should differentiate between Cr III and Cr VI discharge limits to the aquatic environment, as analytical techniques become more sensitive and chromium speciation specific, and environmental awareness rises., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Sea urchins serve as an essential niche for benthic ecosystems and are valuable seafood for humans. However, little is known about the microplastics (MPs) accumulation in sea urchins. Here, we investigated the abundances and characteristics of MPs in specific tissues of wild sea urchins for 12 sites across 2, 900 km of coastlines in northern China. Sea urchins from all sites were detected to have MPs, with a total detection rate of 89.52%. The MPs abundance in sea urchins from all sites ranged from 2.20 ± 1.50 to 10.04 ± 8.46 items/individual or 0.16 ± 0.09 to 2.25 ± 1.68 items/g wet weight. The samples from Dalian were found to have the highest value by individual, and samples from Lianyungang had the highest value by gram. Furthermore, MPs were found in different tissues of sea urchins, i.e., gut, coelomic fluid and gonads. The highest abundance of MPs was found in the gut of sea urchins, followed by coelomic fluid and gonads. The size of MPs ranged from 27 to 4742 μm, and the mean size found in gut was bigger than coelomic fluid and gonads. More interestingly, the MPs abundance increased with the decrease of anus size, shell diameter and gonad index (the wet weight ratio of gonad to total soft tissues). The MPs were dominated by fiber in shape, blue-green in colour and cellophane in composition. The high MPs abundance in sea urchins indicates the potential risks to human as they are consumed in many parts of the world, particularly in Asia and Europe., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Cyanobacteria are photoautotrophic organisms which occur in aquatic and terrestrial environments. They have the potential to produce toxins which pose a threat to human and animal health. This review covers the global distribution of the common cyanotoxins and related poisoning cases. A total of 468 selected articles on toxic cyanobacteria, dating from the earliest records until 2018, were reviewed. Most of the articles were published after 2000 (72%; 337 out of 468), which is consistent with the recent growth in interest in the analysis, toxinology and ecotoxicology of cyanotoxins. Animal and/or human poisoning cases were described in more than a third of the overall publications (38%; 177 out of 468). The reviewed publications showed that there were 1118 recorded identifications of major cyanotoxins in 869 freshwater ecosystems from 66 countries throughout the world. Microcystins were the most often recorded cyanotoxins worldwide (63%; 699 out of 1118), followed by cylindrospermopsin (10%; 107 out of 1118), anatoxins (9%; 100 out of 1118), and saxitoxins (8%; 93 out of 1118). Nodularins were the most rarely recorded cyanotoxins (2%; 19 out of 1118); however, there were also reports where cyanotoxins were not analysed or specified (9%; 100 out of 1118). The most commonly found toxic cyanobacterial genera were Microcystis spp. (669 reports), Anabaena spp. (397 reports), Aphanizomenon spp. (100 reports), Planktothrix spp. (98 reports), and Oscillatoria spp. (75 reports). Furthermore, there were 183 recorded cyanotoxin poisonings of humans and/or animals. Out of all toxic cyanobacterial blooms reviewed in this paper, the highest percentage of associated poisonings was found in North and Central America (39%; 69 cases out of 179), then Europe (20%; 35 out of 179), Australia including New Zealand (15%; 27 out of 179), and Africa (11%; 20 out of 179), while the lowest percentage was related to Asia (8%; 14 cases out of 179) and South America (8%; 14 cases out of 179). Events where only animals were known to have been affected were 63% (114 out of 182), whereas 32% (58 out of 182) of the investigated events involved only humans. A historical overview of human and animal poisoning episodes associated with cyanobacterial blooms is presented. Further, geographical data on the occurrence of cyanotoxins and related poisonings based on the available literature are shown. Some countries (mainly European) have done very intensive research on the occurrence of toxic cyanobacteria and cyanotoxins, and reported related ecotoxicological observations, while in some countries the lack of data is apparent. The true global extent of cyanotoxins and associated poisonings is likely to be greater than found in the available literature, and it can be assumed that ecotoxicological and hygienic problems caused by toxic cyanobacteria may occur in more environments.