Bioaccumulation Of Toxic Metals Research Articles

Evaluation of heavy metals contamination in Rabbit Fish (Signus Sutor) from selected landing sites in Zanzibar, Tanzania

The increase of heavy metals concentrations in aquatic and terrestrial environments and their toxicity is of global concern. The bioaccumulation of toxic metals in fish poses a serious risk to human health when consumed. This study assessed the quality of Rabbit fish (Signus Sutor) and their associated health risks from four landing sites (namely Malindi, Mazizini, Kizimkazi and Matemwe) in Zanzibar. The concentrations of toxic metals, including Lead (Pb), Cadmium (Cd), Copper (Cu), Chromium (Cr), Nickel (Ni), and Arsenic (As), in the fish muscle were scrutinized using inductively coupled plasma optical emission spectrometry (ICP-OES). The detected mean concentration (mg/kg) of Pb, As, Cr, Cd, Cu, and Ni at Malindi were 0.25±0.14, 2.22±0.44, 0.02±0.02, 0.01±0.00, 0.02±0.02 and 0.00±0.00 respectively; at Kizimkazi were 0.39±0.39, 2.30±0.44, 0.11±0.01, 0.07±0.04, 0.17±0.13 and 0.15±0.04 respectively: at Matemwe were 0.38±0.12, 0.52±0.14, 0.04±0.02, 0.05±0.01, 0.65±0.21 and 0.09±0.03 respectively; and Mazizini were 0.21±0.12, 5.56±1.37, 0.02±0.02, 0.03±0.01, 0.05±0.02 and 0.15±0.05 respectively. The mean concentration levels detected for all the elements in the fish gathered from all four landing sites were below international and local maximum (FAO/WHO) permissible limits for human consumption, except for Arsenic (As) and lead (Pb). The study also investigated the relationship between fish size and metal concentration which shows a positive correlation for Cu and Ni. However, it was negative for the remaining metals, possibly due to ecological and metabolic differences. The study emphasizes the necessity for regular monitoring of the marine environment and enforcement of hygienic regulations, as well as the treatment of land-based pollutants before they are discharged into the marine environment to protect fish quality.

Bioaccumulation of Toxic Metals in Freshwater Fish in Brazil: Gaps, Applications, and Future Directions for Environmental Biomonitoring

Bioaccumulation of Toxic Metals in Freshwater Fish in Brazil: Gaps, Applications, and Future Directions for Environmental Biomonitoring

Analysis of Toxic Metals Found in Shark Fins Collected from a Global Trade Hub.

As human activities release increasingly more fossil fuel-derived emissions directly into the atmosphere, terrestrial, aquatic, or marine ecosystems, the biomagnification and bioaccumulation of toxic metals in seafood is an ever more pressing concern. As apex predators, sharks are particularly susceptible to biomagnification and bioaccumulation. The consumption of shark fin is frequent throughout Asia, and their ingestion represents a pathway through which human exposure to potentially unsafe levels of toxic metals can occur. Shark fins processed for sale are difficult, if not impossible to identify to the species level by visual methods alone. Here, we DNA-barcoded 208 dried and processed fins and in doing so, identified fourteen species of shark. Using these identifications, we determined the habitat of the shark that the fin came from and the concentrations of four toxic metals (mercury, arsenic, cadmium, and lead) in all 208 samples via inductively coupled plasma mass spectrometry. We further analyzed these concentrations by habitat type, either coastal or pelagic, and show that toxic metal concentrations vary significantly between species and habitat. Pelagic species have significantly higher concentrations of mercury in comparison to coastal species, whereas coastal species have significantly higher concentrations of arsenic. No significant differences in cadmium or lead concentrations were detected between pelagic or coastal species. Our results indicate that a number of analyzed samples contain toxic metal concentrations above safe human consumption levels.

Metal Exposure in Arica, Chile: Examining Toxic Elements.

Bioaccumulation of toxic metals in the population is associated with adverse health effects. Although some elements are essential for humans, high levels of exposure can be dangerous. To describe the levels of Inorganic Arsenic (AsIn), Cadmium (Cd), Chromium (Cr), and Mercury (Hg) in urine, and Lead (Pb) in blood in the population of Arica, Chile. Descriptive study. Beneficiaries of the Health Surveillance Program of Law 20.590 in sites of higher risk of exposure in the commune of Arica were considered eligible. The results of biological samples to measure their concentrations of AsIn, Cd, Cr, Hg in urine, and Pb in blood between August 2016 and May 2021 are described. 9520 samples from a population with a mean age of 40.5 years were studied. 4.21% of the adult population and 6.57% of the children had AsIn values above 35 μg/L, while at least 95 % of the total samples had levels below 33 μg/L. At least 90 % of the samples had Cd levels below 1.1 μg/L, and 8.44 % had Cd levels above 2 μg/L, higher in males (11.67%). There were no values above the reference in children. 99.77% and 99.33% had Cr and Pb values below the reference limit, respectively (using the lowest reference range established by Chile Ministry of Health (MINSAL) < 5 μg/L). Children did not present risk values for Cr, and 0.16% presented Pb concentrations between 5-10 μg/dL. All samples presented Hg concentrations below risk levels (< 10 μg/L). The results of this study suggest that a small percentage of the samples analyzed in the beneficiary population of Arica register metal concentration levels above national reference levels established by MINSAL, mainly AsIn, Cd, and Pb. It is essential to continue biomonitoring to reduce and prevent exposure to these metals, which can have harmful effects on human health.

Concentration and Bioaccumulation of Toxic Metals and Polycyclic Aromatic Hydrocarbons in Soil and Lumbricus Terrestris in Kolo Creek, Niger Delta, Nigeria

The concentration of toxic metals and polycyclic aromatic hydrocarbons (PAHs) in soil, and their bioaccumulation in Lumbricus terrestris in areas around Kolo Creek, Niger Delta, Nigeria were evaluated in this study. 12 soil samples were collected from 4 sites, while Lumbricus terrestris were also collected from areas where soil samples were obtained. Toxic metals were extracted using aqua regia and quantified with a flame atomic absorption spectrophotometer. Extraction of PAHs was achieved by liquid-liquid soxhlet extraction, and quantified with a gas chromatograph-mass spectrometer. The bioaccumulation factor (BAF) for both toxic metals and PAHs were calculated. The results obtained in this study showed that the concentration of all studied toxic metals were within their respective regulatory limits in soil. The BAF for all toxic metals were less than 1 in all sites, indicating minimal bioaccumulation in Lumbricus terrestris. The Ʃ16 PAHs ranged from 7.30 to 77.7 mg kg-1 and 1.10 to 4.75 mg kg-1 in soil and Lumbricus terrestris across the 4 sites, respectively. The BAF values for individual PAHs were less than 1 in all sites, which indicated that PAH congeners were either not bioaccumulated or accumulated PAH congeners were metabolized. Hence, analysis of PAHs metabolites in Lumbricus terrestris is recommended.

Concentration and Bioaccumulation of Toxic Metals and Polycyclic Aromatic Hydrocarbons in Soil and Lumbricus Terrestris in Kolo Creek, Niger Delta, Nigeria

Concentration and Bioaccumulation of Toxic Metals and Polycyclic Aromatic Hydrocarbons in Soil and Lumbricus Terrestris in Kolo Creek, Niger Delta, Nigeria

Concentration and Bioaccumulation of Toxic Metals and Polycyclic Aromatic Hydrocarbons in Soil and Lumbricus Terrestris in Kolo Creek, Niger Delta, Nigeria

Concentration and Bioaccumulation of Toxic Metals and Polycyclic Aromatic Hydrocarbons in Soil and Lumbricus Terrestris in Kolo Creek, Niger Delta, Nigeria

The Occurrences of Heavy Metals in Water, Sediment and Wild Shrimps Caught from Barito Estuary, South Kalimantan, Indonesia

The research investigated the occurrences of heavy metal (Pb, Cu, and Cd) in waters, sediments, and wild shrimps collected from the Barito River estuary. Water and sediment samples were collected from 11 study sites by purposive sampling. At the same time, shrimps samples were captured around the sites. The study showed low levels of heavy metals in water samples; those were: Cd&lt;0.0019 mg/L, Cu&lt;0.001 mg/L, and Pb&lt;0.0019 mg/L. Low levels of heavy metals were also detected in sediment samples, those were Cd &lt;0.24 mg/kg, Cu &lt;0.013-0.69 mg/kg, and Pb&lt;0.024 mg/kg. Heavy metals contaminations were detected in Parapenaeopsis sculptilis, those were Cd = 2.802 mg/kg; Cu = 3.399 mg/kg, and Pb = 1.294 mg/kg. In Acetes japonicus, the heavy metals concentration were Cd = 2.127 mg./kg, Cu = 5.518 mg/ kg, and Pb = 2.723 mg/kg. In Penaeus merguiensi, the heavy metals concentrations were Cd = 8.598 mg/kg, Cu = 6.403 mg/kg, and Pb = 5.433 mg/kg. This study indicated the increases of heavy metals concentrations from water to sediment and finally into the shrimps. The presence of heavy metals in shrimps indicated the bioaccumulation of toxic metals, especially for Pb and Cd concentrations which exceeded the tolerable limit according to JECFA.

TOXIC METALS ACCUMULATION AND HISTOLOGICAL EXAMINATION IN HEART AND KIDNEY TISSUES OF DEVARIO AEQUIPINNATUS FROM THE RIVER TAMIRAPARANI

In the present investigation, the bioaccumulation of toxic metals (Pb, Cd, Cr) concentration and histological evaluation in heart and kidney tissues of were estimated in Devario aequipinnatus, which were caught from the four sampling stations of river Tamiraparani, Tamilnadu, India. The results revealed that Pb, Cd and Cd concentrations in Devario aequipinnatus tissues were considerably lower than at river Tamiraparani sites. Pb concentration was greatest in the kidney (0.16 μg/g dry wt.), Cr content was virtually same in the kidney (0.14 μg/g dry wt.) and in the heart (0.13 μg/g dry wt.), and Cr content was mostly enriched in the kidney (0.14 μg/g dry wt.). However, the results indicated significant variations in the three examined metal levels between the species, as well as unique histological changes in D. aequipinnatus heart and kidney tissues. Despite this, toxic metal accumulation with histological analysis indicated the most substantial differences in the Tirunelveli area. Furthermore, it appears that the vast majority of them are extremely harmful rather than favorable for fish species. This study found that fish products can accumulate metals and carry them on to humans, mostly through food, resulting in chronic or acute illnesses.

Bioaccumulation of Toxic Metals in Commercially Valuable Fish from the Western Region of Ghana

Fish is an important source of protein, however as human impacts on the environment through industrialization, mining and farming among others is resulting in increased concentration of toxic metals in them. The levels of copper (Cu), arsenic (As), zinc (Zn), lead (Pb), cadmium (Cd), mercury (Hg), and selenium (Se) were analysed in fish samples from the southwestern coast of Ghana using acid digestion and atomic absorption spectrophotometer method. A total of 71 fish species were sampled where 35 species were collected in the wet season (October, 2014) whereas 36 species were collected in the dry season (March, 2015). The average levels of heavy metals detected in the wet season were 1.08 mg/kg for Cu, 9.79 mg/kg for Zn, 4.80 mg/kg for Se, 0.06 mg/kg for Pb, 0.03 mg/kg for Hg, 0.02 mg/kg for As, and 0.01 mg/kg for Cd. The average values of heavy metals in fish samples analysed in the dry season were 2.17 mg/kg for Cu, 4.55 mg/kg for Zn, 8.13 mg/kg for Se, 0.06 mg/kg for Pb, 0.03 mg/kg for Hg, 0.09 mg/kg for As, and 0.005 mg/kg for Cd. The results showed that the average levels of toxic metals analysed in the wet season increased in the order of Cd < As <Hg <Pb <Cu < Zn < Se whereas the dry season increased in the order of Cd < Hg < Pb < As <Cu < Zn < Se. The levels of all seven heavy metals were below the FAO/WHO Maximum Permissible Limits (MPL), Australia New Zealand Food Standards, EU, Australian National Health and Medical Research Council (ANHMRC) standards. Hence the consumption of these fish poses no public health concern. The estimated daily intake of the various toxic metals analysed were lower than the daily intake of their respective toxic metals. The non-carcinogenic health risk to adults and children showed that the Total Targeted Hazard Quotients (TTHQ) was less than 1 ( <1) hence poses no health risk to humans.

Heavy metals concentration in spotted babylon snail, Babylonia areolata from Kemasin Coast, Kelantan

Bioaccumulation of toxic metals in marine gastropods, including spotted babylon snail may cause a serious treats to human via food chain. Therefore, the present study investigates the metal contents in the spotted babylon snail, Babylonia areolata based on two sample groups, which are the whole sample and sample without the digestive system using Inductively Coupled Plasma with Atomic Emission Spectrometry (ICP-MS). The concentration pattern of the metals in sample with digestive system was As > Fe > Cu > Zn > Cd > Hg > Sn > Cr and As > Fe > Zn > Cu > Cd > Cr > Hg for sample without digestive system. Overall, the concentrations of these heavy metals were lower in samples without digestive system. Meanwhile, lead (Pb) and antimony (Sb) were not detected in both sample groups. Maximum permissible limits of toxic metals in food were compared and indicated that the heavy metals in B. areolata were within the safety levels except for As (sample with and without digestive system) and Cd (sample with digestive system). The exposure risk of heavy metals in B. areolata at the Kemasin coast, Kelantan is at a permissible level for the consumer provided that the digestive system is removed from the flesh.

Health risk assessment and bioaccumulation of toxic metals in commercially important finfish and shellfish resources collected from Tuticorin coast of Gulf of Mannar, Southeastern India

The present study was mainly focused on the distribution of metals (Cd, Cu, Pb, and Zn) in commercially important marine finfish and shellfish resources collected from the Tuticorin coast of the Gulf of Mannar, Southeastern India. Sixty-six species were collected in all four seasons for the analysis of metals. The order of bioaccumulation of metals in fishes is (Zn > Pb > Cu > Cd), in Crustaceans is (Zn > Pb > Cu > Cd), and in mollusks is (Pb > Zn > Cu > Cd). The human health risk assessment factors such as BCF, THQ, and HI were higher in most of the tested animals. The outcome of the present study will sound the alarm to the community about heavy metal contamination of sea foods. We conclude that continuous monitoring of the ecosystem is essential to the maintenance of the pristine ecosystem and quality of the seafood.

Heavy Metals Causing Toxicity in Fishes

The heavy metals mainly include Pb, Hg, Cd, Cr, Cu, Zn, Mn, Ni, Ag, etc. The heavy metals,Pb,Cu,Zn are considered most toxic to humans, fishes and environment. highly concentrations of heavy metals are harmful They destabilize ecosystems because of their bioaccumulation in organisms, and toxic effects on biota and even death in most living beings. All heavy metals, in spite some of them are essential micronutrients, have their toxic effects on living organisms via metabolic interference and mutagenesis. The bioaccumulation of toxic metals can happen in the body and food chain. So, the toxic metals generally exhibit chronic toxicity. The heavy metals like Pb has significant toxic effects-The heavy metals are important pollutants for fishes, because these are not eliminated from aquatic systems by natural methods, such as organic pollutants, and are enriched in mineral organic substances. happen of heavy metals differs in fishes, depending on their age, development and other physiological factors. the fishes are apopulation which can be highly affected by these toxic pollutants. Heavy metals can have toxic effects on different organ-They can enter into the water by drainage, atmosphere, soil erosion, and all human activities in different ways. As the heavy metals concentrated more in the environment, they enter biogeochemical cycle, leading to toxicity.

Bioaccumulation and heavy metal concentration in tissues of some commercial fishes from the Meghna River Estuary in Bangladesh and human health implications

Despite the beneficial aspect of aquatic food's consumption, bioaccumulation of toxic metals in fish can enhance the health risk for the consumers. Heavy metals were measured from editable tissues of some commercial fish species like Latis calcarifer, Silonia silondia, Clupisoma garua, Planiliza subviridis, Otolithoides pama, Tenulosa ilisa, Rhinomugil corsula, and Aila coila in the Meghna river estuary in Noakhali district. Heavy metals such as As, Pb, Cd, Cu, and Cr were detected by ICP-MS, which were significantly different (p ≤ 0.01), and the hierarchy of all mean concentrations were: Cu (5.14 mg/kg) > Pb (3.79 mg/kg) > As (1.08 mg/kg) > Cr (0.78 mg/kg) > Cd (0.12 mg/kg). The mean concentration of Cu (6.62 mg/kg) imparted to the maximum level in L. calcarifer, which slightly exceeded the Bangladesh food safety guideline. The mean BAFs of the contaminants were found as: Pb (1042.29) > Cr (1036.47) > As (934.84) > Cd (832.77) > Cu (772). Further, L. calcarifer, S. silondia, C. garua, and P. subviridis showed the bioaccumulative status. To assess the health risk effects, estimated daily intake (EDI), target hazard quotient (THQ) and carcinogenic risk (CR) were conducted. THQs for both adult and children consumers were <1, indicating that, consumers would not experience the non-carcinogenic health effects. Although children were more susceptible than adults, CR for all the consumers was found in the acceptable range (10−6 to 10−4).

Analysis of Heavy Metal Accumulation in Fish at Terengganu Coastal Area, Malaysia

Bioaccumulation of toxic metals in fish causes serious threats to human when they are consumed. Thus, the detection of toxic element concentration levels in aquatic component is important. The accumulation of some heavy metals such as Cd, Cu, Fe, Mn, Pb and Zn in fish were determined. Ten species (Selaroides leptolepis, Decapterus maraudsi, Epinephelus lanceolatus, Priacanthus tayenus, Rastrelliger, Megalaspis cordyla, Nibea soldado, Pristipomoides filamentosus, Bramidae and Siganus canaliculatus) were collected from Terengganu coastal area, Malaysia. The analysis was done using inductive coupled plasma-mass spectrometer (ICP-MS) technique. In general, the concentration levels of heavy metals in fish samples are lower than the previous study in various locations. The highest average level of heavy metal recorded in fish is Fe followed by Zn, Mn, Cu, Cd and Pb. The metal concentration found in this study was lower than the national and international recommended dietary allowance (RDA) for human consumption except Fe (52.33 × 10-2 ± 6.39 × 10-2 mg kg-1) which exceeded the limit of 0.3 mg kg-1. Long term monitoring system of metal bioaccumulation in fishes need to be done to provide useful information for the assessment of the potential health risks of metals in Malaysia.

Metal concentrations in homing pigeon lung tissue as a biomonitor of atmospheric pollution.

Atmospheric pollution in urban areas is a major worldwide concern with potential adverse impacts on wildlife and humans. Biomonitoring can provide direct evidence of the bioavailability and bioaccumulation of toxic metals in the environment that is not available with mechanical air monitoring. The current study continues our evaluation of the usefulness of homing pigeon lung tissue as a biomonitor of atmospheric pollution. Homing pigeons (1-2, 5-6, and 9-10+ year old (yo)) collected from Guangzhou during 2015 were necropsied and concentrations of cadmium (Cd), lead (Pb), and mercury (Hg) were measured in lung tissue. Lung Cd and Pb concentrations were significantly greater in 9-10+-year-old pigeons compared with those in other age groups, indicating their bioavailability and bioaccumulation. Lung Pb and Cd concentrations measured in 5-yo pigeons collected from Guangzhou during 2015 were significantly lower than concentrations reported in 5-yo homing pigeons collected from Guangzhou during 2011 and correlated with concentrations measured using mechanical air monitoring. In addition to temporal differences, spatial differences in concentrations of Cd, Pb, and Hg reported in ambient air samples and in pigeon lung tissues collected from Beijing and Guangzhou are discussed.

Accumulation and interaction of fluoride and cadmium in the soil-wheat plant system from the wastewater irrigated soil of an oasis region in northwest China

Contamination of agricultural soil with high concentrations of fluorine (F) and cadmium (Cd) have raised significant concerns regarding their impacts on human health but the relationship between F and Cd in soil-wheat plant system in an oasis region has not been investigated. This paper aims to study the accumulation and interaction of F and total Cd in the soil-wheat plant system while considering the potential risks of F and Cd to human health. Soil samples were collected from wastewater-irrigated oasis regions, Dongdagou and Xidagou. The concentrations of total F (FT) and Cd in soils from the Dongdagou and Xidagou stream basins were higher than those in uncontaminated soils (F=270.25mgkg−1, Cd=0.10mgkg−1). Water-soluble F (FW) and FT contributed to F concentrations in underground parts of wheat when the samples were collected from Dongdagou, however, F in aboveground parts may be mainly influenced by atmospheric F. The main source of F in wheat plants collected from the Xidagou site may be mainly controlled by atmospheric F, including aboveground and underground parts. Soils in the studied region pose a potentially severe health risk for humans via bioaccumulation of toxic metals through the food chain, and therefore, are not suitable for planting wheat meant for human consumption. Cd had a significantly negative effect on F accumulation in wheat root from Dongdagou (P<0.01). This field study provided F-Cd interactions that occur in soils from an oasis region at environmentally relevant concentrations.

Influence of taxa, trophic level, and location on bioaccumulation of toxic metals in bird’s feathers: A preliminary biomonitoring study using multiple bird species from Pakistan

Increasing concentrations of heavy metals in the environment and their effects on ecosystems and biota is still an imminent threat, particularly in developing parts of the globe. The aim of the present study was to screen the heavy metal concentrations in multiple bird species across Pakistan and to preliminary evaluate the influence of taxa, trophic level, and geographical location on heavy metal accumulation in various bird species. For this purpose, we measured the concentration of 9 heavy metals (Pb, Cd, Cr, Ni, Co, Cu, Fe, Zn and Mn) in feathers of 48 bird species from different localities in Pakistan. Species exhibited heterogeneous levels of heavy metals in feathers with marked inter and intra specific variations. Mean concentrations of studied metals in feathers followed the trend Fe>Zn>Cu>Pb>Mn>Cr>Ni>Co>Cd. Species belonging to closely related taxa (families) showed comparable metal concentrations in their feathers, inferring potential phylogenetic similarities in metal exposure or accumulation. In general, concentrations of metals were greatest in carnivorous species followed by omnivorous and insectivorous birds, and granivores showing minimal levels (p<0.000). Furthermore, concentrations of metals varied significantly between locations (p<0.000) exhibiting highest concentrations in Punjab province and Baluchistan, probably due to higher industrial and agricultural activity and runoff, respectively. With certain limitation, influence of trophic level, taxonomic affiliation and sampling location of birds on toxic metal accumulation was also statistically corroborated through principal component analysis (PCA). This study highlights that despite restricted emissions, heavy metals persist in the local environment and may pose elevated risks for the studied bird species in Pakistan.

Characteristics, functions, and applications of metallothionein in aquatic vertebrates

The documents on Metallothioneins (MTs) in aquatic creatures, especially focusing on their function as biomarkers in environmental monitoring programmes, are vast and increasing. There are, however, few papers to summary the physiological role of MTs in aquatic organisms especially on development. The multifaceted roles of MTs include involvement in homeostasis, protection against heavy metals and oxidant damages, and metabolic regulation, sequestration and/or redox control. In this paper, we have collected published information on MTs in aquatic organisms—pisces, amphibians, mammals etc, and analyzed their function in these aquatic animals. MTs have four main functions in aquatic vertebrate. They are respectively bioaccumulation of toxic metals and detoxification, homeostatic regulation of metals, protection against oxidative stress and neuroprotective mechanism. MTs separate in different tissues and they have various distributions in different tissues of aquatic vertebrate, including liver, gills, kidney, testes and brain. MTs can be induced by a variety of environmental and physiological factors, among which, heavy metals are the main kind of MTs inducers in aquatic vertebrate. Here we pay more attention on the essential metals copper (Cu) and zinc (Zn) and the non-essential metals cadmium (Cd), silver (Ag), lead (Pb) and mercury (Hg).

Health risk assessment of zinc, chromium, and nickel from cow meat consumption in an urban Nigerian population.

Meat consumption is increasingly becoming a larger part of diets worldwide. However, the bioaccumulation of toxic metals from anthropogenic pollution is a potential health risk to human health. To measure the daily intake of zinc, chromium, and nickel from cow meat consumption and assess the possible health risks in an urban population in Nigeria. Dried meat samples were digested with 3 : 2HNO3 : HClO4 v/v. Zinc, chromium, and nickel concentrations were determined with atomic absorption spectrophotometer. Daily intakes of meat were obtained using a food frequency questionnaire (FFQ). The estimated daily intakes (EDI) (μg/person/day) ranges were: zinc (10 496-13 459), chromium (310·90-393·73), and nickel (26·72-34·87). Estimated daily intake for zinc was 15-30% of provisional maximum tolerable daily intake (PMTDI) and for nickel it was 8-15% of tolerable daily intake (TDI). Chromium intakes were above recommended daily intake (RDI). Target hazard quotient (THQ) for nickel and zinc were within WHO/FAO limit. There was no evidence of possible health risk to consumers with regard to zinc and nickel. However, chromium intake should be of utmost concern, while disposal of tanning waste should be checked.