Cadmium and lead accumulation in important food crops due to wastewater irrigation: Pollution index and health risks assessment

The contamination of farm soils with heavy metals (HMs) has raised significant concerns due to the increased bioavailability and accumulation of HMs in agricultural food crops. To address this issue, a survey experiment was conducted in the suburbs of Multan and Faisalabad to investigate the spatial distribution, bioaccumulation, translocation, and health risks of cadmium (Cd) and lead (Pb) in agricultural crops. The results show a considerable concentration of Cd and Pb in soils irrigated with wastewater, even though these levels were below the permissible limits in water and soil matrices. The pollution index for Cd was mostly greater than 1 at the selected sites, indicating its accumulation in soil over time due to wastewater irrigation. Conversely, the pollution index for Pb was below 1 at all sites. Among the plants, Zea mays accumulated the highest concentration of Cd and Pb. The translocation factor from soil to root was highest for Brassica olearecea (7.037 for Cd) and Zea mays (6.383 for Pb). The target hazard quotient (THQ) value of Cd exceeded the non-carcinogenic limit for most vegetables. The highest value was found in Allium cepa (5.256) and the lowest in Allium sativum (0.040). In contrast, the THQ level of Pb was below the non-carcinogenic limit for most vegetables, except for Allium cepa (1.479), Solanum lycopersicum (1.367), and Solanum tuberosum (1.326). The study highlights that Allium cepa poses the highest health risk for humans, while Medicago sativa poses the highest risk for animals due to Cd and Pb contamination. These results underscore the urgent need for effective measures to mitigate the health risks associated with HM contamination in crops and soils.

A review on the clean-up technologies for heavy metal ions contaminated soil samples

The soil contamination with heavy metal ions is one of the grave intricacies faced worldwide over the last few decades by the virtue of rapid industrialization, human negligence and greed. Heavy metal ions are quite toxic even at low concentration a swell as non-biodegradable in nature. Their bioaccumulation in the human body leads to several chronic and persistent diseases such as lung cancer, nervous system break down, respiratory problems and renal damage etc. In addition to this, the increased concentration of these metal ions in soil, beyond the permissible limits, makes the soil unfit for further agricultural use. Hence it is our necessity, to monitor the concentration of these metal ions in the soil and water bodies and adopt some better technologies to eradicate them fully. From the literature survey, it was observed that three main types of techniques viz. physical, chemical, and biological were employed to harness the heavy metal ions from metal-polluted soil samples. The main goal of these techniques was the complete removal of the metal ions or the transformation of them into less hazardous and toxic forms. Further the selection of the remediation technology depends upon different factors such as process feasibility/mechanism of the process applied, nature and type of contaminants, type and content of the soil, etc. In this review article, we have studied in detail all the three technologies viz. physical, chemical and biological with their sub-parts, mechanism, pictures, advantages and disadvantages.

Determination of Heavy Metal Levels and Health Risk Assessment of Raw Cow Milk in Guelma Region, Algeria

During the recent decades, adverse effects of unexpected contaminants, such as heavy metals on raw cow milk quality, have threatened human health. The objective of this study was to determine heavy metal levels in raw milk collected from autochthonous bovine breeds in the eastern region of Algeria. Eighty-eight pooled milk samples were analyzed using atomic absorption spectrometry for Pb, Cd, Cr, Cu, Ni, Fe, and Zn, and dietary risks were estimated for infants, children, and adults with minimum, average, and maximum milk consumption scenarios. Results revealed that Pb (0.94 ± 0.49 mg/kg), Cd (0.03 ± 0.01 mg/kg), and Cu (0.14 ± 0.08 mg/kg) levels in all analyzed samples were higher than their corresponding maximum residue levels (MRLs). The task hazard quotient (THQ) values suggest potential risk for infants in the three scenarios from Pb, Cd, and Cr; for children in the three scenarios from Pb and in the high scenario from Cr; and for adults in the medium and high scenarios from Pb. The hazard index (HI) values were higher than 1, and the contributions of each metal to the overall HI followed a descending order of Pb, Cr, Cd, Ni, Zn, Cu, and Fe with values of 68.19%, 15.39%, 6.91%, 4.94%, 3.42%, 0.88%, and 0.28%, respectively. Our results indicated that there may be a potential risk of heavy metals, especially Pb, for infants through raw cow milk consumption. Moreover, data actualization and continuous monitoring are necessary and recommended to evaluate heavy metal effects in future studies.

Vermiremediation and comparative exploration of physicochemical, growth parameters, nutrients and heavy metals content of biomedical waste ash via ecosystem engineers Eisenia fetida

Vermicomposting of Biomedical waste ash (BA) by the earthworm Eisenia fetida was studied with cow dung (CD) as nutrient medium. For 105 days, experiment was carried out in seven vermireactors containing varying ratios of BA and CD. Earthworm activity significantly reduced the pH (8.61-7.24), Electrical conductivity (EC) (4.1-1.62), Total organic carbon (TOC) (38.6-14.92), and Carbon and nitrogen (C/N ratios) (145.4-8.2) of all BA ratios. Levels of Total kjeldahl nitrogen (TKN) (0.26-1.82), Total available phosphorus (TAP) (0.22-0.64), Total potassium (TK) (2.05-12.08), and Total sodium (TNa) (47.53-92.26) were found to be increasing in the postvermicompost mixture. Although heavy metals content decreased from initial to final, it becomes below the permissible limits in the end product. The results showed that earthworm growth and fecundity were best in vermireactors containing 10-25% of BA. The best reproduction and growth of earthworms, demonstrate the vermicomposting's ability to manage hazardous solid wastes like BA. Use of vermitechnology to manage BA has not been performed yet in any kind of the research. Finally, it was determined that vermicomposting can be incorporated into overall plan for BA management. Thus nutrient-rich, detoxified, and physiochemically stable product may be used safely in agricultural processes.

Investigation of toxic heavy metals content and estimation of potential health risks in Chinese herbal medicine

The content of toxic heavy metals (THMs), including lead (Pb), arsenic (As), cadmium (Cd), and mercury (Hg), was determined in a total of 10,245 samples for 279 types of Chinese herbal medicine (CHM) using a validated inductively coupled plasma mass spectrometry method. The exceeding rate (ER) for the four THMs were calculated based on diverse permissible limits (PLs) established by different organizations and national pharmacopeias. Cluster analysis was used to classify the degree risk of THMs contamination according to the calculated ER. Results revealed that Cibotii rhizome, Selaginellae herba, Morindae officinalis radix, Asprellae ilicis radix, and Toxicodendri resina exhibited high-degree risk of Pb contamination. Eckloniae/Laminariae thallus, Spirodelae herba, and Naturalis indigo possessed high-degree risk of As contamination. Tetrapanacis medulla, Centipedae herba, Cyathulae radix, Linderae radix, Meretricis/Cyclinae concha, and Tabanus displayed high-degree risk of Cd contamination. Toxicodendri resina has high-degree risk of Hg contamination. In addition, six types of CHM, including Asprellae ilicis radix, Toxicodendri resina, Eckloniae/Laminariae thallus, Fossilia Ossis Mastodi, Haematitum, and Hedyotidis diffusae herba, may have non-carcinogenic health risk after consumption of raw materials because the calculated hazard quotient and hazard index were over 1.0. In summary, these data provide useful information about THMs contamination in CHM.

Assessment of heavy metal content of commonly consumed herbal medicines in Sindh, Pakistan

In Pakistan, herbal medicines are extensively consumed by a major portion of people for the treatment of numerous ailments. Nowadays, the contamination of heavy metals in herbal medicines is a serious concern due to its toxic effects on human health. In the present study, quantitative evaluation of four heavy metals, namely, iron (Fe), cadmium (Cd), nickel (Ni), and copper (Cu), was carried out in forty herbal medicines, frequently sold in the markets of Sukkur and Khairpur, Pakistan, without any quality assurance. Conventional wet acid digestion method was used for the dissolution of samples, and the concentration of heavy metals was determined by using flame atomic absorption spectrometry. Diverse concentration of metals was observed in different herbal medicines. The levels of Fe, Cd, Ni, and Cu were in the range of 30.3-798 mg/kg, 0.002-0.007 mg/kg, 1.52-27.3 mg/kg, and 15.2-194 mg/kg, respectively. The findings of our study were also compared with the WHO maximum permissible limits. It was observed that the concentrations of these heavy metals in most of the analyzed samples were within the permissible limits set by the WHO. Only a few samples of herbal medicines exceeded the recommended levels of Ni and Cu. These medicines should be regularly checked for quality assurance to avoid chronic exposure of metal to human beings.

Heavy metals levels in raw cow milk and health risk assessment across the globe: A systematic review

This systematic review presents the potential toxicity of heavy metals such as lead (Pb), mercury (Hg), cadmium (Cd), iron (Fe), nickel (Ni), aluminum (Al), and copper (Cu) in raw cow milk, focusing on their contamination sources and on the assessment of the related human health risk. Multiple keywords such as "raw cow milk, heavy metals, and human health" were used to search in related databases. A total of 60 original articles published since 2010 reporting the levels of these metals in raw cow's milk across the world were reviewed. Data showed that the highest levels of Ni (833 mg/L), Pb (60 mg/L), Cu (36 mg/L) were noticed in raw cow milk collected in area consists of granites and granite gneisses in India, while the highest level of Cd (12 mg/L) was reported in barite mining area in India. Fe values in raw cow milk samples were above the WHO maximum limit (0.37 mg/L) with highest values (37.02 mg/L) recorded in India. The highest Al level was (22.50 mg/L) reported for raw cow's milk collected close to food producing plants region in Turkey. The Target Hazard Quotients (THQ) values of Hg were below 1 suggesting that milk consumers are not at a non-carcinogenic risk except in Faisalabad province (Pakistan) where THQ values = 7.7. For the other heavy metals, the THQ values were >1 for Pb (10 regions out of 70), for Cd (6 regions out of 59), for Ni (3 out of 29), and for Cu (3 out of 54). Exposure to heavy metals is positively associated with diseases developments. Moreover, data actualization and continuous monitoring are necessary and recommended to evaluate heavy metals effects in future studies.

Toxic Metal Pollution in Pakistan and Its Possible Risks to Public Health

Environmental pollution has increased many folds in recent years and in some places has reached levels that are toxic to living things. Among pollutant types, toxic heavy metals and metalloids are among the chemicals that pose the highest threat to biological systems (Jjemba 2004). Unlike organic pollutants, which are biodegradable, heavy metals are not degraded into less hazardous end products (Gupta et al. 2001). Low concentrations of some heavy metals are essential for life, but some of them like Hg, As, Pb and Cd are biologically non-essential and very toxic to living organisms. Even the essential metals may become toxic if they are present at a concentration above the permissible level (Puttaiah and Kiran 2008). For example, exposure to Zn and Fe oxides produce gastric disorder and vomiting, irritation of the skin and mucous membranes. Intake of Ni, Cr, Pb, Cd and Cu causes heart problems, leukemia and cancer, while Co and Mg can cause anemia and hypertension (Drasch et al. 2006). Similarly, various studies indicated that overexposure to heavy metals in air can cause cardiovascular disorders (Miller et al. 2007; Schwartz 2001), asthma (Wiwatanadate and Liwsrisakun 2011), bronchitis/emphysema (Pope 2000), and other respiratory diseases (Dominici et al. 2006).

High levels of mercury in wetland resources from three river basins in Ghana: a concern for public health

Crustaceans, mollusks, and fish are wetland resources that constitute an important source of protein and foreign exchange for the Ghanaian population, and many species of these are sold in the open market and restaurants, yet studies on their heavy metal contents are generally scarce. This paper evaluates the levels of mercury in five species of crustaceans, two species of mollusks, and ten species of fish inhabiting three river basins with different catchment activities in Ghana. These include the Ankobra Basin, characterized with mining and agriculture, Densu Basin, associated with urban waste discharges and agriculture, and Lower Volta River Basin, associated with agricultural activities. Mercury concentration was highest in Ankobra (2.5 ± 2.59 μg g^-1) followed by Densu (1.75 ± 1.35 μg g^-1) and Volta (0.74 ± 1.46 μg g^-1). The mercury load of the organisms range from <0.1 to 4 μg g^-1 with the highest load in Cynoglossus senegalensis at Ankobra. Except for Panaeus notialis from Densu and Ankobra, and three other species from Ankobra (Tympanotonus fuscatus, Cardisoma armatum, Callinectes amnicola) in which mercury was not detected, mercury loads of all the organisms were above the permissible limit of 0.5 mg kg^-1 established by Commission Regulation-EC (2006) for fishery products and muscle meat of fish. Weekly quantities of crustaceans and mollusks considered safe for consumption by adults ranged from 88 and 1000 g while that of the fishes were between 70 and 700 g (on a dry weight basis) depending on the species. It was clear that some caution needs to be exercised in the consumption of Ghana's fresh and brackish water fisheries.

Cadmium concentration in liver and muscle of silky shark (Carcharhinus falciformis) in the tip of Baja California south, México

Cadmium concentrations were determined in the tissues of muscle and liver of Carcharhinus falciformis (silky shark) sampled in Todos Santos, Baja California South, Mexico. This is one of the main shark species for human consumption in Mexico. Results indicate that accumulation of Cd varied in both sexes, based on its metabolism, sex, maturity and other biological characteristics. High Cd values were observed in the liver of adults of male (529.61μgg(-1)) and female (457.43μgg(-1)), whereas, in muscular tissues it was low (0.37μgg(-1)) than the prescribed permissible limits for seafood (0.5μgg(-1)). Substantial correlations were observed between body length and Cd values in adults except young male due to faster growth rate and its metabolism. The study indicated the impact of environmental conditions in the accumulation of Cd and its risk to the food web structure in the marine environment and health hazard for humans.

Metal concentrations in demersal fish species from Santa Maria Bay, Baja California Sur, Mexico (Pacific coast)

Concentrations of 11 trace metals (Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn, Cd, As, Hg) in 40 fish species from Santa Maria Bay, Baja California Sur, Mexico, the strategically important area for marine mammals and organisms were analyzed. Based on their concentrations the ranking of metals Fe>Zn>Ni>Cr>Mn>Pb>Cu>Co>As>Cd>Hg suggests that organism size, metabolism and feeding habits are correlated with metal concentrations. Local geological formations affect the concentrations of different metals in the aquatic environment and are subsequently transferred to fishes. The correlation analysis suggests that metabolism and nurturing habits impact the concentration of metals. Concentrations of Fe and Mn appear to be influenced by scavenging and absorption processes, which vary by species. The considerable variability in the metal concentrations obtained in different species underscores the importance of regular monitoring.