Toxic metals in cigarettes and human health risk assessment associated with inhalation exposure

Association of blood metals with anxiety among adults: A nationally representative cross-sectional study

BACKGROUND

Previous evidence demonstrated the inconsistent associations between metals and anxiety. The purpose of this study was to evaluate the individual and joint effects of blood lead (Pb), cadmium (Cd), mercury (Hg), selenium (Se) and manganese (Mn) on anxiety in the general population.

METHODS

Data of 4000 participants (aged≥20 years) in the study were retrieved from the National Health and Nutrition Examination Survey (NHANES) 2011-2012. Multiple logistic regression, restricted cubic splines (RCS) logistic analysis, and weighted quantile sum (WQS) regression were fitted to explore the possible effects of single and mixed metal exposures on anxiety. Moreover, this association was assessed by smoking group.

RESULTS

In the study, 24.60 % of participants were in an anxiety state. In logistic regression, blood Pb, Cd, Hg, Se and Mn were not significantly associated with anxiety in all participants. After stratified by smoking group, blood Cd was positively associated with anxiety in the current smoking group [P = 0.029, OR (95 %): 1.708(1.063, 3.040)], whereas not in other groups. In RCS regression, we observed a linear dose-response effect of blood Cd on anxiety stratified by smoking group. In WQS analysis, mixed metal exposures were positively associated with anxiety [P = 0.033, OR (95 %): 1.437(1.031, 2.003)], with Cd (33.69 %) contributing the largest weight to the index.

CONCLUSIONS

Our study showed that excessive exposure to Cd is a significant risk factor for anxiety, and the co-exposures to Pb, Cd, Hg, Se and Mn were positively related with the risk of anxiety in current smokers.

Inhalation exposure to toxic heavy metals in nail salon technicians and health risk assessment using Monte Carlo simulation

OBJECTIVE

Nail salons offer a developing and diverse occupation for many women, especially the new generation. Due to the increasing apprehension surrounding heavy metals in dust caused by filing nails containing dried nail polish, the present study was designed aimed to health risk assessment of heavy metals in breathing zone of nail salon technicians (NSTs).

METHODS

This is a cross-sectional study that was conducted in NSTs. The concentration of Cadmium (Cd), Lead (Pb), Nickel (Ni), Chromium (Cr) and Manganese (Mn)in breathing zone of 20 NSTs was determined using ICP-OES.

RESULTS

The metal concentrations were in the following order: Mn > Pb > Ni > Cr > Cd with corresponding arithmetic mean values of0.008, 0.0023, 0.0021, 0.001 and 0.0006 mg m-3, respectively, which are exceeded the recommended levels stated in the indoor air guidelines. The average lifetime carcinogenic risk (LCR) for Cr, Cd, Ni and Pb was calculated 0.0084, 0.00054, 0.00026 and 1.44 E - 05, respectively. The LCR values of all metals (except Pb) exceeded the acceptable level set by the USEPA. The mean of Hazard quotients (HQ) for Mn, Cd, Cr, Ni and Pb were calculated to be23.7, 4.74, 2.19, 0.51 and 0.0.24, respectively. The sensitivity analysis showed that, the exposure frequency (EF) for Cr and Ni had the strong effects on generation of both LCR and HQ. Furthermore, the concentrations of Mn, Cd and Pb had strong impacts on the HQ generation and the concentration of Cd and Pb had main effects on LCR generation.

CONCLUSION

To effectively reduce pollutant concentration, it is recommended to install a ventilation system near nail salon work tables and conduct continuous monitoring and quality control of nail products.

Heavy metals in popularly sold branded cigarettes in Bangladesh and associated health hazards from inhalation exposure

Tobacco products are widely recognized as a major contributor to death. Cigarette smoke contains several toxic chemicals including heavy metals particulate causing high health risks. However, limited information has been available on the health risks associated with the heavy metals in cigarettes commonly sold in the Bangladeshi market. This study evaluated the concentrations and potential health risks posed by ten concerned heavy metals in ten widely consumed cigarette brands in Bangladesh using an atomic absorption spectrometer. The concentration (mg/kg) ranges of heavy metals Pb, Cd, Cr, As, Co, Ni, Mn, Fe, Cu, and Zn vary between 0.46-1.05, 0.55-1.03, 0.80-1.2, 0.22-0.40, 0.46-0.78, 2.59-3.03, 436.8-762.7, 115.8-184.4, 146.6-217.7, and 34.0-42.7, respectively. We assume that the heavy metals content among cigarette brands is varied due to the differences in the source of tobacco they use for cigarette preparation. The carcinogenic risks posed by heavy metals follow the order of Cr > Co > Cd > As > Ni > Pb, while the non-carcinogenic risks for Cu, Zn, Fe, and Mn were greater than unity (HQ > 1), except for Fe. The existence of toxic heavy metals in cigarette tobacco may thus introduce noticeable non-carcinogenic and carcinogenic health impacts accompanying inhalation exposure. This study provides the first comprehensive report so far on heavy metal concentration and associated health risks in branded cigarettes commonly sold in Bangladesh. Hence, this data and the information provided can serve as a baseline as well as a reference for future research and have potential implications for policy and legislation in Bangladesh.

Comparison of the rate of certain trace metals accumulation in indoor plants for smoking and non-smoking areas

Tobacco smoke causes to release severe toxic metals into the environment. It is recognized as the most significant issue in indoor air quality. Pollution and toxic substances in smoke quickly spread and penetrate the indoor environment. Environmental tobacco smoke is responsible for lowering indoor air quality. There is much evidence that poor air quality occurs with inadequate ventilation conditions in indoor environments. The plants have been observed to absorb the smoke in the environment into their own body like a sponge. The plant species in this study can be used easily in almost every office, home, or other indoor areas. Using indoor plants is very beneficial in biomonitoring and absorbing these trace metals. Some indoor plants have shown successful performance as biomonitors for health-damaging pollutants. The study aims to determine the concentration of three trace metals (Cu, Co, and Ni) using five indoor ornamentals frequently used in smoking areas, namely D. amoena, D. marginata, F. elastica, S. wallisii, and Y. massengena. The Ni uptake and its accumulation in S. wallisii, and Y. massengena increased in correlation with smoke areas. However, the rate of accumulation of Co and Cu was found to be independent due to consideration of the environmental emissions. Consequently, our results suggest that F. elastica is more resistant to smoking, whereas S. wallisii would be a better choice as a biomonitoring plant of tobacco smoke.

The association between environmental cadmium exposure, blood pressure, and hypertension: a systematic review and meta-analysis

We performed a systematic and meta-analysis study to find the association between cadmium (Cd) exposure and blood pressure (BP)/hypertension (HTN) in exposed general populations. We searched main databases for literature published between year 2000 and April 15, 2021. Quality assessment was performed with the Joanna Briggs Institute (JBI) critical appraisal tools. Heterogeneity between studies was determined by I-squared (I²) statistic. The random effects model was used to determine the association between blood and urine Cd levels with hypertension. The overall standard differences in mean for Cd level in hypertensive and control groups were 3.34, 1.79, and 8.09 based on samples from blood, urine, and hair, respectively. The overall standard differences in mean for Cd level in the low and high exposure groups were - 0.795 and - 1.036 based on blood and urinary samples, respectively. Our findings indicate a positive relationship between blood and hair Cd levels and hypertension. We also found that hair is the optimal biological sample to find the relationship between Cd exposure and hypertension for both genders. However, more studies are needed to confirm these findings.

Content of toxic components of cigarette, cigarette smoke vs cigarette butts: A comprehensive systematic review

The commercially sold cigarettes contain more than 7000 chemicals, and their combustion produces potential toxicants in mainstream smoke (MS), sidestream smoke (SS), secondhand smoke (SHS), thirdhand smoke (THS), and discarded cigarette butts (CBs). We conducted a systematic review of published literature to compare the toxicants produced in each of these phases of tobacco combustion (MS, SS, and CBs). The initial search included 12,301 articles, but after screening and final restrictions considering the aims of this review, 159 published studies were selected for inclusion. Additionally, SHS and THS are briefly discussed here. Overall, polycyclic aromatic hydrocarbons (PAHs) and other aromatic hydrocarbons have been represented in more studies than other compounds. However, metals and nitrosamines were detected in higher concentrations than other components in SS. The concentrations of most PAHs and other aromatic hydrocarbons in MS and SS are higher compared to concentrations found in CBs. Also, the concentrations of all the studied carbonyl compounds, aldehydes and ketones in SS and MS were higher than in CBs. The mean levels of alcohols and phenols in SS were higher than those reported for both MS and CBs. Tobacco toxicants are inhaled by smokers and transmitted to the environment through SS, SHS, THS, and discarded CBs. However, further studies are necessary to assess adverse effects of toxicants found in CBs and THS not only on human health, but also on the environment and ecosystems. The results of this review provide updated information on the chemical contents of MS, SS, SHS, THS, and CBs. It adds to the growing understanding that smoking creates major health problems for smokers and passive smokers, but also that it generates environmental hazards with consequences to the ecosystems and human health through discarded CBs, SHS, and THS exposure.

Analyzing pesticides and metal(loid)s in imported tobacco to Saudi Arabia and risk assessment of inhalation exposure to certain metals

Exposure to toxic chemicals through smoked tobacco is a significant global public health issue due to their genotoxic and carcinogenic properties. The study aims to (1) measure Arsenic (As), Cadmium (Cd), Cobalt (Co), Chromium (Cr), Mercury (Hg), Nickle (Ni), lead (Pb), and 407 pesticides in tobacco commercialized in Saudi Arabia; and (2) evaluate human health risks associated with smoking tobacco. Thus, we analyzed 60 tobacco samples per brand from eight of the most popular tobacco brands in the Saudi market. The analyzed tobacco contained significant concentrations of toxic metal (loid)s and banned pesticides. Twenty-three out of 407 pesticide residues were found, with an average concentration of 0.004-1.155 µg/g. Average concentrations of As, Cd, Co, Cr, Hg, Ni, and Pb for all brands were 0.16, 0.57, 0.75, 1.36, 1.94, 0.01, and 0.37 µg/g, respectively. The risk assessment indicated that high cancer risks are associated with exposure to As, Cd, Cr, and Ni, while lower risks are associated with Pb. Additionally, the potential cancer risk estimated for Cr was higher than other toxic elements. The cumulative cancer risks (95%) under three different cases for all brands were greater than the permissible limits (=10-4). The chances of getting cancer through inhalation of particulate As, Cd, Cr, Ni, and Pb was 4 in 10 000 cases in the best case scenario (1 cigarette per day). Therefore, metal content in cigarette tobacco should be reduced to improve public health.HIGHLIGHTSAll tested brands contained banned pesticide residues except for brand C.Tobacco samples contained significant concentrations of toxic metal(loid)s.A high risk of developing cancer is associated with exposure to As, Cd, Cr, and Ni, while a lower risk is associated with exposure to Pb.

Effect of Heating on Physicochemical Property of Aerosols during Vaping

Many electronic cigarette manufacturers have offered different types of “high-end mods” that allow for controlled heating of the e-liquid. However, the controlled heating condition can drastically alter the inhaled aerosols’ physical properties and chemical substances, causing potential health risks. To investigate the contribution of heating on aerosol properties, we used four common power settings in the mods to conduct a physicochemical analysis. Our data showed that the aerosol mass and nicotine content in the aerosols increased at high power. Additionally, high power led to aerosolization of a viscous component in the e-liquid, increasing the viscosity of aerosol. However, the pH of the aerosol was constant regardless of the applied power. In addition, high-power operation made nicotine prone to oxidation, resulting in the color of the aerosol turning yellow. Lastly, we demonstrated that e-cigarette aerosol could contain various metals, including aluminum, arsenic, cadmium, chromium, copper, iron, magnesium, nickel, lead, and zinc. Even though these metal contents proportionally increased with the power setting, they remained far below the recommended exposure limits. Our finding demonstrates that the heating conditions of the e-cigarette change the physicochemical properties of the aerosols and their metal contents, thereby possibly affecting users’ oral and respiratory systems.

Potentially toxic elements leachates from cigarette butts into different types of water: A threat for aquatic environments and ecosystems?

Trillions of cigarette butts (CBs) are released into the environment and the leached potentially toxic elements (PTEs) from CBs may contaminate the environments. In this study, the leaching of PTEs including both heavy metals and metalloids (metal(loid)s) from CBs into deionized water (DW), tap water (TW), and seawater (SW) was checked during the different contact times (from 60 min to 60 days). According to the results, PTEs were leached from CBs into different water samples. However, there were no significant differences between leachates in DW and TW samples (p > 0.05). The results of the distribution coefficient indicated the high tendency of most PTEs to enter the liquid phase. The levels of leached PTEs into DW and TW exceeded the standards of surface freshwater to maintain aquatic life. Although the maximum level of leached metal(loid)s into DW, TW, and SW occurred at different times, for each type of water sample no significant differences were found among the levels of most PTEs at various contact times. Based on the results, the levels of leached metal(loid)s from CBs in seawater peak soon after being released into the water, while for the freshwater, they occur after some days. This phenomenon could possibly have short-term and long-term effects on marine and freshwater organisms, respectively. Due to the ability of the dissolved PTEs to integrate into the aquatic/terrestrial food web and threaten human health, some control measures regarding the disposal of CBs are necessary.

Sources of 24-h personal exposure to PM2.5-bound metals: results from a panel study in Wuhan, China

Atmospheric PM2.5-bound metals have been widely addressed, but research on the exposure levels and sources of personal PM2.5-bound metals among urban community residents is limited. The aim of this study is to explore the exposure levels and sources of 24-h personal PM2.5-bound metals among community inhabitants in Wuhan, China. We conducted a penal study of 216 observations with measurements of 16 metals bounded to 24-h personal PM2.5 samples in April-May, 2014, 2017. Analyses of covariance were used to compare PM2.5-bound metal levels across different living habits and ambient conditions. Principal component analysis (PCA) with varimax rotation was performed to explore PM2.5-bound metal sources. Personal PM2.5-bound aluminum (Al) (113.41 ng/m3) showed the highest geometric mean (GM) concentration, followed by lead (Pb) (90.89 ng/m3), zinc (Zn) (67.71 ng/m3), and iron (Fe) (51.85 ng/m3). The elevated levels of PM2.5-bound Al, vanadium (V), manganese (Mn), arsenic (As), rubidium (Rb), cadmium (Cd), and thallium (Tl) were found in participants with cigarette smoke exposure, compared with those without. The concentrations of Rb and strontium (Sr) were positively associated with the time spent outdoors. The increased concentration of nickel (Ni) was found in individuals who spent > 30 min/day in traffic. The elevated levels of V, Mn, and cobalt (Co) were associated with a short distance from dwellings to the main road. The results of PCA showed that PM2.5-bound metals might come from five sources: As, selenium (Se), Rb, Cd, Tl, and Pb from cigarette smoke exposure; Al, V, Mn, Fe, and Sr from crustal dust; copper (Cu) and antimony (Sb) from industrial activities; Ni and Co from traffic emission; and Zn from coal combustion. The concentrations of PM2.5-bound metals in this study were at moderate levels. Cigarette smoke exposure, industrial activities, traffic emission, and coal combustion might be major anthropogenic sources of personal PM2.5-bound metal exposures in Wuhan, China.

Pathophysiological Correlation between Cigarette Smoking and Amyotrophic Lateral Sclerosis

Cigarette smoke (CS) has been consistently demonstrated to be an environmental risk factor for amyotrophic lateral sclerosis (ALS), although the molecular pathogenic mechanisms involved are yet to be elucidated. Here, we propose different mechanisms by which CS exposure can cause sporadic ALS pathogenesis. Oxidative stress and neuroinflammation are widely implicated in ALS pathogenesis, with blood–spinal cord barrier disruption also recognised to be involved in the disease process. In addition, immunometabolic, epigenetic and microbiome alterations have been implicated in ALS recently. Identification of the underlying pathophysiological mechanisms that underpin CS-associated ALS will drive future research to be conducted into new targets for treatment.

Mercury, cadmium, and lead in cigarettes from international markets: concentrations, distributions and absorption ability of filters

Mercury (Hg), cadmium (Cd), and lead (Pb) concentrations in marketed cigarettes from South Korea, Vietnam, Japan, Indonesia, Taiwan, Thailand, the United Kingdom (UK), Belgium, Italy, Finland, and France were investigated. The cigarettes from Vietnam and Thailand had the highest trend of Hg. Meanwhile, Cd was found higher in cigarettes from Thailand, the UK, and Belgium. Pb concentrations in cigarettes from Belgium, the UK, and Korea were higher than others. The average of these heavy metals concentrated in cigarettes was in the order of Pb > Cd > Hg. Furthermore, the contents of these heavy metals in cigarette leaves were much higher than in filter and rolling paper. There was a significant positive correlation between Hg and Cd, but no correlation between Cd and Pb and between Hg and Pb. Significant positive correlations of nicotine with Hg and Cd but not Pb in the cigarette were observed. Activated carbon filters (Ce-C) absorb Cd and Pb from cigarette leaves and rolling paper indicated a higher trapping trend than cellulose acetate filter without activated carbon (Ce). The trapping ratios of Ce-C (Cd: 5.53%, Pb:5.41%) were higher than Ce (Cd:3.09%, Pb:5.49%). On the other hand, Hg had lower absorption by both types of filters (Ce:0.15%, Ce-C:0.02%). This revealed that Hg, Cd and Pb absorption ability by both filters was relatively lower to the total concentration of these metals in tobacco leaves and rolling paper. The concern was that the higher concentrations of metals such as Hg, Cd and Pb in cigarettes might exist in mainstream smoke.

Leachate Analysis of Heavy Metals in Cigarette Butts and Bricks Incorporated with Cigarette Butts

Billions of cigarette butts (CBs) are discarded as litter in the environment every year worldwide. As CBs have poor biodegradability, it can take several years for them to break down while leaching toxic chemicals and heavy metals. Mohajerani et al. (2016), based on long-term research, developed a method for the recycling of CBs in fired clay bricks with promising results. This paper presents and discusses the leaching behavior of potentially hazardous metals from used, unused, and shredded used CBs, and unfired and fired clay bricks incorporating CBs. The leachate analysis was conducted according to the Australian Bottle Leaching Procedure (ABLP) for pH values 2.9, 5.0, and 9.2. The aim was to quantify the amount of heavy metals leached, determine the relationship between the metal concentration leachate, pH of the solution and condition of the sample, and examine the effect of firing on the leaching capability of bricks. The leachate results were then compared to the concentration limits for heavy metals set by the United States Environmental Protection Authority (USEPA) national primary drinking water and the Environmental Protection Authority (EPA) solid industrial waste hazard categorization thresholds to assess the suitability of fired clay bricks incorporating CBs. Metals Cu, Zn, Mn, Al, Fe, Ti, and Ba demonstrated the highest leachate concentrations for pH 2.9 and pH 5.0 for used CBs. This suggests that used CBs are more prone to leaching heavy metals in areas with highly acidic rain compared to the natural range of precipitation. The leaching behavior of fired bricks incorporating CBs was considerably lower than that for the unfired bricks due to the immobilization of heavy metals during the firing process. However, the leaching of Cr and Ni was almost completely impeded after the firing of the bricks, and more than 50% of all the tested heavy metals were hindered.

Analysis of the elements and metals in multiple generations of electronic cigarette atomizers

BACKGROUND

Since their release in 2004, electronic cigarettes (ECs) and their atomizers have undergone significant evolution.

OBJECTIVE

The purpose of this study was to evaluate and compare the elemental/metal composition of atomizers in cartomizer and tank style ECs produced over a 5-year period.

METHODS

Popular cartomizer and tank models of ECs were dissected and photographed using a stereoscopic microscope, and elemental analysis of EC atomizers was done using scanning electron microscopy coupled with energy dispersive x-ray spectroscopy.

RESULTS

Eight elements/metals were found in most products across and within brands purchased at different times. These included chromium, nickel, copper, silver, tin, silicon, aluminum, and zinc. Iron and lead were found in some but not all products, while manganese, cobalt, molybdenum, titanium, and tungsten were only found in a few of the products. The metals used in various components were often similar in cartomizer and tank models. Filaments were usually chromium and nickel (nichrome), although in some newer products, the filament also contained iron, copper, and manganese. The thick wire in earlier products was usually copper coated with silver, while in some newer products, the thick wire was predominantly nickel. In all products, the wick was silica, and sheaths, when present, were fiberglass (silicon, oxygen, calcium, aluminum, magnesium). Wire-to-wire joints were either brazed or clamped with brass (copper and zinc), and air-tube-to-thick wire joints, when present, were usually soldered with tin. Tank style products generally lacked a thick wire and sheaths.

CONCLUSION

In general, atomizer components in ECs were remarkably similar over time and between brands. Certain elements/metals were consistently found in most models from all generations, and these should be studied carefully to determine if their transfer to aerosols affects user's health and if their accumulation in trash affects the environment.

Levels of trace elements in PM10 collected at roadsides of Addis Ababa, Ethiopia, and exposure risk assessment

Estimation of personal exposure to air pollution is needed to identify high-risk population and to develop mitigation strategies. In this study, an assessment of the potential effects of short-term exposure to PM₁₀ and the elements bound within PM₁₀ was conducted. Samples were obtained from the ten sub-cities of Addis Ababa (three sampling points from each) during the commuting time (traffic congestion and taxi queues). A particle counter consisting of a portable sampling unit with multi-fraction dust samplers was used for sample collection. The elemental composition was analyzed by inductively coupled plasma-optical emission spectroscopy (ICP-OES). The mean concentrations of PM₁₀ ranged from 206 to 308 μg m^-3. The highest concentrations of pollutants were found in the major open-market part of the city, Addis Ketema. The lowest concentrations were found at the old-town, Arada sub-cities. The concentration of trace elements (Fe, Cd, As, Cr, Pb, B, Ni, Co, Sn, Cu, and Zn) bound in PM₁₀ ranged from below detectable limit to 0.981 μg m^-3. Regardless of the sampling sub-city, the overall patterns of the mean concentration of elements bound in PM₁₀ were found in the following increasing order of Cr < Cd < As < Co < Ni < Cu < Fe < Pb < Sn < B < Zn < Mn. The results showed that the primary source of Zn, Cr, and Cd may be emissions from on-road vehicles, tire and brake wear. Pb originates mainly from industries and suspended soil dust at the roadside, whereas As, Mn, and B are associated with dust resuspension and biomass and biofuel combustion, respectively. The carcinogenic and non-carcinogenic risks due to chronic exposure to trace elements bound in PM₁₀ at the roadside were assessed in accordance with the U.S. Environmental Protection Agency (US EPA) guidelines. It was determined that Mn, As, and Cd contributed substantially to the inducement of non-carcinogenic health problems to children and adults as a result of exposure while in close proximity to the roadsides.

Polymorphisms in gene MMP-2 modify the association of cadmium exposure with hypertension risk

BACKGROUND

Cadmium exposure has been inconsistently related with hypertension. However, epidemiologic data on the genetic susceptibility to the hypertensive effect of cadmium exposure are limited.

OBJECTIVES

We investigated whether the associations between cadmium exposure and hypertension risk differed by genetic polymorphisms in MMPs genes.

METHODS

The present study of 497 hypertension cases and 497 healthy controls was conducted in a Chinese population. Urinary cadmium levels were measured with inductively coupled plasma-mass spectrometer (ICP-MS). Multivariable logistic regression models were analyzed after controlling major confounders.

RESULTS

Within the multivariable logistic regression models, compared with the lowest tertile, the highest tertile of urinary cadmium had a 1.33-fold (95% CI: 1.01, 1.93) increased risk of hypertension. Carriers of rs243865 T allele and rs243866 A allele in MMP-2 were suggested to have increased risks of hypertension. The associations of urinary cadmium with hypertension risk were modified by rs14070 (P-value for interaction = 0.022) and rs7201 (P-value for interaction = 0.009) in gene MMP-2. Positively significant trends for increasing odds of hypertension with cadmium levels were observed among the wild types of rs14070 and rs7201, respectively.

CONCLUSIONS

Increasing urinary cadmium concentrations were positively associated with hypertension risk in a Chinese population, and the associations were modified by polymorphism of rs14070 and rs7201 in gene MMP-2.

Chemical Speciation and Characterization of Trace Metals in Dry Camellia sinensis and Herbal Tea Marketed in Nigeria

BACKGROUND

Trace metals from anthropogenic activities have been found to occur in tea brands and pose potential human health risks to consumers.

OBJECTIVES

The present study assessed the concentrations of trace metals in green, black and herbal tea brands using a modified Community Bureau of Reference sequential extraction method.

METHODS

Fifteen (15) Camellia sinensis and eight (8) herbal tea samples commonly consumed in Nigeria were collected and analyzed for trace metals. The concentrations of cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), vanadium (V), and zinc (Zn) in extract fractions were analyzed using microwave plasma atomic emission spectroscopy (MP-AES).

RESULTS

Trace metals were detected in all of the samples investigated. The concentrations of trace metals in 4 stages (soluble/exchangeable/carbonates bound fraction, reducible fraction, oxidizable fraction, residual fraction) of sequential and pseudo-total metal extraction procedures are presented. The concentrations of Cd, Cr, Cu, Mn, Ni, Pb, V, and Zn in the exchangeable/carbonate bound fraction for green tea ranged between 0.27-1.47, ND-0.33, ND-0.44, 7.05-33.04, 0.23-0.69, ND-0.51, ND-0.16 and 0.18-1.99 mg/kg, ND-0.73, 0.15-0.36, 0.36-0.59, 1.38-30.07, 0.15-0.54, 0.05-0.76, 0.15-0.34 and 0.27-0.77 mg/kg and 0.54-0.64, 0.25-0.41, 0.35-0.47, 18.72-23.98, 0.30-0.55, 0.15-0.21, 0.15-0.23 and 0.30-0.48 mg/kg for hebal tea, respectively.

CONCLUSION

The metal content in the investigated tea indicated low to enhanced concentrations. Locally produced black teas recorded relatively low trace metal contents compared to the green and herbal tea samples. The most bioavailable trace metal was Mn, while Zn was most preferably bound to the residual fraction. Cadmium, Cr, Cu, Ni, Pb, and V were distributed at varied concentrations among other extractable phases. Daily consumption of the investigated tea products may expose consumers to potentially toxic metals as well as essential elements.

COMPETING INTERESTS

The authors declare no competing financial interests.