Heavy metal contamination has gradually become a highly significant global issue due to its continual existence in the environment and bioaccumulation in the ecosystems, posing deleterious risks to human health. The major objectives of the review is to investigate the sources, pathways, and toxicological impacts of heavy metals such as cadmium, lead, mercury, and arsenic, elucidating their health consequences and plausible mitigation strategies. Furthermore, the review explores the dual origins of heavy metal contamination; natural geological processes and anthropogenic activities such as industrial emissions, mining, and agricultural practices. These heavy metals seep into soil, water, and food chains, leading to bioaccumulation, bio-magnification and causing significant health risks, including cardiovascular diseases, neurological disorders, and reproductive toxicity. Additionally, the addition of indigenous case studies from Nigeria, such as lead poisoning in Zamfara State and contamination in the Great Kwa River of Cross Rivers State underscores the disproportionate impact of heavy metal pollution in developing nations. The key findings from this review via the selected case studies revealed the socio-economic and environmental dimensions of the issue, providing a contextual understanding of region-specific vulnerabilities and health outcomes. To address these problems, the review evaluates already existing mitigation strategies, including chelation therapy and phytoremediation, while proposing sustainable, cost-effective solutions for reducing exposure and mitigating impacts. It emphasizes the importance of integrative approaches involving policy, community engagement, and technological innovations to fight heavy metal contamination effectively. In conclusion, this review contributes to the understanding of heavy metal toxicity, giving and showcasing very much important insights into the sources and health implications of contamination. By integrating theoretic Introduction Heavy metals are naturally occurring elements with a relatively high density present in the ecosystem ( De Carvalho Machado and Dinis-Oliveira, 2023 ; Ali and Khan, 2018 ). They are popularly known as metals of environmental concern ( Kothapalli, 2021 ; Rahman and Singh, 2020 ). Heavy metal pollution or contamination in water is one of the most consequential environmental issues ( Mishra et al. , 2019 ). Inorganic arsenic (iAs) is the most prevalent toxic form of arsenic in drinking water, which increases the rate of skin diseases in humans ( Abtahi et al. , 2023 ). Cadmium has been implicated to cause hypercalciuria in humans ( Obaid et al. , 2023 ). A recent review revealed that of this exposure to cadmium in human leads to a 31% increase in risk of lung cancer ( Farahmandian et al. , 2024 ). Moreso, mercury have been implicated to cause kidney diseases in humans as a result of bioaccumulation ( Kumar et al. , 2023 ). It is imperative to understand that heavy metals are present in the earth’s crust and are part of the exponential scale of the naturally occurring elements ( Ali and Khan, 2018 ). The primary source of heavy metals in the environment is the geologic origin of the major and accessory minerals contained in the soil and rocks ( Subasinghe et al. , 2022 ; Hultman and Pollard, 2022 ). Heavy metals are naturally occurring elements and are released in diverse ways from rocks and soils ( Bharti and Sharma, 2022 ). Weathering, tectonic activity, and pan-genetic processes represent a trio of principal mechanisms of heavy metal geological introduction from primary or secondary minerals ( Wu et al. Heavy metal poisoning can lead to a variety of illnesses in humans, some potentially lethal, including blood ( Zahra et al. , 2017 ) and neuromuscular problems ( Toledano, 2020 ) and many forms of cancer ( Khanniri et al. , 2023 ). Moreso, as human population increases year in year out, heavy metal pollution never decreases instead it increases significantly, leading to potential health hazards as a result of changes in environmental conditions and demographic trends ( Crocetto et al. Furthermore, Cadmium is a highly toxic non-essential element used in electroplating, the television industry, battery production, and coating agents of iron and steel products ( Sable et al. , 2024 ). The major route of human exposure of cadmium is via the ingestion of polluted food, such as rice, shellfish and vegetables ( Zhao et al. , 2023 ) or through inhalation of tobacco smoke ( Genchi et al. , 2020b ). Alarminly, a huge proportion of cigarettes are haphazardly intermittently irrigated with cadmium fertilizers, which may subsequently release the heavy metal (cadmium) from tobacco during smoking. In addition to ROS generation, metals have also been found to have a direct effect on DNA via the formation of metal-DNA adducts where a single base pair is displaced and metal ions then sit in the space created ( Marchi, 2023 ). a. Oxidative stress The human body has a conglomerate of elements such as heavy metals that perform numerous functions in the body ( Mitra et al. , 2022 ). Some metals are essential for the homeostasis of the organisms (REF). while some are toxic when they overly interact and get supplemented in the cells (REF). A plethora of heavy metals such as lead, mercury, arsenic, and cadmium have no specified physiological function ( Balali-Mood et al. , 2021 ). The epigenetic alterations caused by Arsenic exposure are often mediated through changes in DNA methylation (DNAm) patterns ( Dutta and Ruden, 2024 ). 5. Health effects of heavy metal exposure and case studies Throughout the regions of the world, humans are habitually exposed to various toxic metals via water, food, and air ( Parui et al. , 2024 ). In the Homo sapiens species these metals are known to bioaccumulate and biomagnify thereby leading to injury in a plethora of body systems ( Parida and Patel 2023 ; Shah and Kumar, 2022 ; Semwal et al. , 2022 ).

The abundant and renewable resources from fruit by-products are getting emphasis on their valorization. These by-products may contain toxic substances due to factors such as cultivation, harvesting, transportation, preservation, or processing. Hence, presenting scientific overviews of the toxicological qualities and detoxification trends of these by-products are critical for implicating their possible valorization. The present demand for valorization of fruit by-products requires emphasis and methodologies for the detoxification of any toxicants to develop healthier products. This review emphasized the toxicological qualities of by-products from fruits for which the maximum global production occurred in 2022. In this review, heavy metals (arsenic, cadmium, cobalt, chromium, nickel, lead, and mercury), mycotoxins, toxicant organic compounds, anti-nutritional factors, and pesticide/fungicide residues of the selected fruit byproducts were discussed. Current trends to reduce possible toxicants of these by-products during their valorization were emphasized. Novel functional foods valorized from these fruit by-products and future perspectives of detoxification were also focused on in this review. Box 1177, Sfax, 3018, Tunisia 3 Department of Food Science and Technology, University of the Peloponnese, Antikalamos, 24100, Kalamata, Greece ✉ Corresponding author. 21 5 2025 20 1 20251105 20251105 24 5 2025 © 2025 the author(s), published by De Gruyter This work is licensed under the Creative Commons Attribution 4.0 International License. Abstract The abundant and renewable resources from fruit by-products are getting emphasis on their valorization. These by-products may contain toxic substances due to factors such as cultivation, harvesting, transportation, preservation, or processing. Certain fruits also contain naturally occurring toxic compounds that can be harmful if consumed excessively [ 4 , 5 ]. For example, some nightshade fruits contain solanine, a glycoalkaloid that acts as a natural defense mechanism against pests and diseases [ 6 , 7 ]. Oxalates are another toxic component that can be present in fruit byproducts. Oxalates are naturally occurring substances found in many plants. Hence, ingesting high amounts of oxalates can lead to the formation of kidney stones in susceptible individuals [ 8 ]. Nitrites are an increased risk of cancer and other health issues. Percentage waste part of common fruits prioritized in the current review are depicted in Figure 1b . Nearly half of the fruit parts are discarded in terms of peels, seeds, rinds, husks, rags, roots, and pomace during the day-to-day activities in homes and agro-processing industries. It is important to consider that these fruit by-products are important plant sources containing many bioactive substances, dietary fiber, minerals, and others [ 24 , 25 ]. Moreover, fruit by-products contain bioactive substances that show potent ant-microbial activities [ 25 ]. They reported that IC 50 values of the Pomelo seed oils were in the range of 16.31 and 28.8 mg/mL, which is acceptable since the non-cytotoxic compounds have IC 50 values greater than 1 mg/mL. The cytotoxicity dose of the Majia pomelo seed oil concentration tested in human liver cancer HepG 2 cells was in the range of 500–4,000 μg/mL, which were also found to be non-toxic. 3.3. Mandarin The etoxazole concentration (0.010∼0.637 mg/kg), which is a type of pesticide in citrus ( Citrus reticulata Blanco ) peel, was found larger than its pulp part (0.010–0.011 mg/kg). Moreover, during daily administration of 1,420 mg polyphenols enriched with ellagitannin extracts for 4 weeks, human safety was also found safe [ 101 ]. Figure 3 depicts some toxicant components present in grapefruit pomace. Figure 3 Toxicant elements and chemicals in grapefruit by-product (pomace). 4. Toxicological qualities of tropical fruit by-products Tropical fruit by-products considered here are the peel, pomace and/or seed from avocado, pineapple, banana, papaya, watermelon, and melon fruits. Tropical fruit by-products contained hazard heavy metals. de Matuoka e Chiocchetti et al. Besides, the presence of isothiocyanate in the papaya seed oil implies the thioglucosinolate present in the seed hydrolysis to some degree by the thioglycosidase enzyme [ 109 , 110 ]. Thus, the presence of these toxicants limits the use of papaya seed and its oil for animal or human consumption unless further processing to remove these toxicants could be adopted. Pineapple skin contains larger (597 mg/kg) total toxic metal contents than orange peel, watermelon rind, banana peel, apple pomace, strawberry pomace, and grape pomace, in all of which it is below 50 mg/kg [ 14 ]. 4.5. During the apple processing, its pomace, peel, and seeds are found as by-products. Some studies have reported that apple peels contain heavy metals such as Cr and Cd. In particular, the heavy metal concentrations (Cu = 3.7, Zn = 4.13, Cr = 2.25, and Cd = 0.002 mg/kg) analyzed in apple peel were below the safety qualification for agricultural products except for chromium (Cr = 0.5 mg/kg) [ 41 ]. Moreover, heavy metals (Cd, Cr, Ni, and Pb) found in apple pomace were analyzed below the permissible limits to implicate their non-toxicity during biogas production ( Table 1 ) [ 37 ]. Fruit by-products may contain naturally occurring plant toxins like cyanogenic glycosides, which include AMG. ANFs can be minimized by applying novel detoxification technologies and using fermentation [ 16 , 180 ]. Novel detoxification techniques like microwave heating are being applicable to reduce heat labile ANFs such as phytic acid, trypsin inhibitors, tannins, saponins and oxalate in food products [ 16 ] as shown in Figure 4 . 9. Novel functional foods from fruit by-products free from toxication Many functional foods can be derived from different food by-products. Fruits contain vitamins, antioxidants, minerals, and dietary fiber. Globally, 14% of food is lost during harvest.

McNeill Abstract Arsenic is a naturally occurring element known for its chronic and acute toxicity. The solubility of arsenic is highly dependent on environmental conditions. The soils of Cache Valley, UT, contain naturally occurring arsenic. Bioretention systems rely on a combined plant-soil system to remove pollutants carried by stormwater, typically nitrogen, phosphorus, dissolved organic carbon, and select metals. Phosphate from stormwater potentially increases arsenic mobility, which makes stormwater pollutant loading an important factor for evaluating risks associated with stormwater bioretention. Pollutant removal in these systems occurs through sorption of contaminants onto the soils, physical filtration by the soil media, and uptake by plants. Plants play an important role in bioretention systems since many of the stormwater pollutants are also plant nutrients. Rhizosphere biological processes can alter soil chemistry; an adverse effect of those alterations is the mobilization of naturally occurring arsenic. The aim of this study was to determine which factors influenced arsenic mobilization in soil pore water in stormwater bioretention systems. To do so, a variety of plant types and stormwater pollutant concentrations were applied as treatments to a bioretention site in Cache Valley, UT. From this study, certain plant types were determined to result in minimal arsenic concentrations in the soil pore water and mobile soils minerals phases. Checksum bd213f373d8629e1879d66787d74224b Recommended Citation Patterson, Kaisa H., "Arsenic Release From Surface Soils Induced by Stormwater Bioretention" (2020). All Graduate Theses and Dissertations, Spring 1920 to Summer 2023 . 7763.

dangerous and can be toxic. The fluorine mineral fluorspar was known as early as 1529. Early chemists realized that fluorine compounds contain an undiscovered The halogens are a group in the periodic table consisting of six chemically related elements, fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and the radioactive elements astatine (At) and tennessine (Ts), though some authors would exclude tennessine as its chemistry is unknown and is theoretically expected to be more like that of gallium. In the modern IUPAC nomenclature, this group is kno The halogens are a group in the periodic table consisting of six chemically related elements, fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and the radioactive elements astatine (At) and tennessine (Ts), though some authors would exclude tennessine as its chemistry is unknown and is theoretically expected to be more like that of gallium. In the modern IUPAC nomenclature, this group is known as group 17. The word "halogen"… H2 +… Approximately six million metric tons of the fluorine mineral fluorite are produced each year. Four hundred-thousand metric tons of hydrofluoric acid are made each year. Fluorine gas is made from hydrofluoric acid produced as a by-product in phosphoric acid manufacture. Approximately 15,000 metric tons of fluorine gas are made per year. The mineral halite is the mineral that is most commonly mined for chlorine, but the minerals carnallite and sylvite are also mined for chlorine. Forty million metric tons of chlorine are produced each year by the electrolysis of brine. Approximately 450,000 metric tons of bromine are produced each year. Fifty percent of all bromine produced is produced in the United States, 35% in Israel, and most of the remainder in China. Historically, bromine was produced by adding sulfuric acid and bleaching powder to natural brine. However, in modern times, bromine is produced by electrolysis, a method invented by Herbert Dow. It is also possible to produce bromine by passing chlorine through seawater and then passing air through the seawater. In 2003, 22,000 metric tons of iodine were produced. Chile produces 40% of all iodine produced, Japan produces 30%, and smaller amounts are produced in Russia and the United States. Until the 1950s, iodine was extracted from kelp. However, in modern times, iodine is produced in other ways. One way that iodine is produced is by mixing sulfur dioxide with nitrate ores, which contain some iodates. Iodine is also extracted from natural gas fields. Even though astatine is naturally occurring, it is usually produced by bombarding bismuth with alpha particles. Tennessine is made by using a cyclotron, fusing berkelium-249 and calcium-48 to make tennessine-293 and tennessine-294.