Metals In Tea Research Articles

Assessing the health risks of heavy metals and seasonal minerals fluctuations in Camellia sinensis cultivars during their growth seasons

The risk assessment of heavy metals in tea is extremely imperative for the health of tea consumers. However, the effects of varietal variations and seasonal fluctuations on heavy metals and minerals in tea plants remain unclear. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to evaluate the contents of aluminum (Al), manganese (Mn), magnesium (Mg), boron (B), calcium (Ca), copper (Cu), cobalt (Co), iron (Fe), sodium (Na), zinc (Zn), arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), and antimony (Sb) in the two categories of young leaves (YL) and mature leaves (ML) of tea (Camellia sinensis) cultivars throughout the growing seasons. The results showed significant variations in the contents of the investigated nutrients both among the different cultivars and growing seasons as well. Furthermore, the average concentrations of Al, Mn, Mg, B, Ca, Cu, Co, Fe, Na, Zn, As, Cd, Cr, Ni, and Sb in YL ranged, from 671.58–2209.12, 1260.58–1902.21, 2290.56–2995.36, 91.18–164.68, 821.95–5708.20, 2.55–3.80, 3.96–25.22, 37.95–202.84, 81.79–205.05, 27.10–69.67, 0.028–0.053, 0.065–0.127, 2.40–3.73, 10.57–12.64, 0.11–0.14 mg kg−1, respectively. In ML, the concentrations were 2626.41–7834.60, 3980.82–6473.64, 3335.38–4537.48, 327.33–501.70, 9619.89–13153.68, 4.23–8.18, 17.23–34.20, 329.39–567.19, 145.36–248.69, 40.50–81.42, 0.089–0.169, 0.23–0.27, 5.24–7.89, 18.51–23.97, 0.15–0.19 mg kg−1, respectively. The contents of all analyzed nutrients were found to be higher in ML than in YL. Target hazard quotients (THQ) of As, Cd, Cr, Ni, and Sb, as well as the hazard index (HI), were all less than one, suggesting no risk to human health via tea consumption. This research might provide the groundwork for essential minerals recommendations, as well as a better understanding and management of heavy metal risks in tea.

Pollution indices of selected metals in tea (Camellia sinensis L.) growing soils of the Upper Assam region divulge a non-trifling menace of National Highway

The study investigated the influence of a National Highway (NH) traversing tea estates (TEs) on heavy metal (HM) contamination in the top soils of Upper Assam, India. The dispersion and accumulation of six HMs, viz. cadmium (Cd), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), and zinc (Zn), within tea-growing soils were assessed using diverse indices: contamination factor (CF), degree of contamination (DC), enrichment factor (EF), geo-accumulation index (Igeo), modified degree of contamination (MDC), Nemerow pollution index (PINemerow), pollution load index (PLI), potential ecological risk factor (Eri), and potential ecological risk index (RI). The order of HM prevalence was Fe > Mn > Zn > Ni > Cu > Cd. Elevated Cd levels near the NH prompted immediate attention, while Cd and Zn showed moderate pollution in CF, EF, and RI. The remaining metals posed minimal individual risk (Eri< 40), resulting in an overall contamination range of “nil to shallow,” signifying slight contamination from the studied metals. From MDC values for investigated metals, it was found to be “zero to very low degree of contamination” at all locations except the vicinity of NH. Soil pollution, as determined by PLI, indicated unpolluted soils in both districts, yet PINemerow values indicated slight pollution. The statistical analysis revealed that there is a significant decrease in most of the indices of HM as the distance from NH increases. The application of multivariate statistical techniques namely Principal Component Analysis and Cluster Analysis showed the presence of three distinct homogenous groups of distances based on different indices. This investigation underscores NH-associated anthropogenic effects on TE soil quality due to HM deposition, warranting proactive mitigation measures.

Current Status and Health Risk Assessment of Heavy Metals Contamination in Tea across China.

Tea is a non-alcoholic beverage popular among Chinese people. However, due to the application of chemical and organic fertilizers in the tea planting process, the environment pollutionaround the tea plantation, and the instruments used in the processing, heavy metal elements will accumulate in the tea, which brings health risks for tea consumers. This study summarized heavy metal concentrations from 227 published papers and investigated the current contamination status of tea and tea plantation soils, and, finally, the risk of heavy metal exposure to tea consumers in China is assessed, in terms of both non-carcinogenic and carcinogenic risk. The average contamination of six heavy metals in tea-arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), and lead (Pb)-were 0.21, 0.14, 1.17, 14.6, 0.04, and 1.09 mg/kg, respectively. The areas with high concentrations of heavy metals in tea were concentrated primarily in southwest China, some areas in eastern China, and Shaanxi Province in northwest China. The non-carcinogenic risks of heavy metals in tea are all within safe limits. The national average HI value was 0.04, with the highest HI value of 0.18 in Tibet, which has the largest tea consumption in China. However, the carcinogenic risks of Cd in Shaanxi Province, Anhui Province, and southwest China exceed the acceptable range, and due attention should be given to these areas.

Toxic Metal Detection in Various Types of Tea from Certain Regions of China: Spatial Pollution Characteristics and Potential Health Risk Assessment

Tea is one of the most popular beverages in the world, but toxic metals in tea could threaten human health. The toxic metal pollution status of tea in China at a national level remains unclear. Here, we detected the cadmium (Cd) and arsenic (As) concentrations of tea collected from 22 provinces in China. The major points are the following: (1) average concentrations of Cd and As of tea samples in China were 1.163 and 0.485 mg/kg, respectively; the Cd but not As levels exceeded the standards from the Ministry of Agriculture of the People’s Republic of China (NY 659-2003). Cd and As average concentrations were higher in the Southern and Western regions at 5.730, 0.071 and 0.510, 0.580 mg/kg, respectively, compared with the Eastern and Northern regions at 0.203, 0.040 and 0.455, 0.463, respectively. The concentration of Cd was highest in kuding tea at 21.98 mg/kg, whereas the As concentration was highest in jasmine tea at 0.76 mg/kg. (2) The health risk assessment yielded target hazard quotients for Cd and As of 0.1989 and 0.1432, respectively. The total hazard index was 0.3421, and the cancer risk was 8.949 × 10–4. (3) The principal component analysis revealed higher Cd pollution in the Western and Southern areas, which may be related to mining activities. This is the first national-scale investigation of the toxic metals Cd and As in tea across China. Our findings provide a useful reference for ensuring the quality and safety of tea production and suggest the need for constant monitoring of toxic metals in tea to limit the risk of exceeding permitted limits.

Evaluation of Related Potential Health Risks for Dry Black Tea from Baghdad&amp;#39;s Markets

Background: Tea is the most widely consumed beverage on the planet. Teaconsumption is helpful to human health since it includes various key elements. Thepresence of heavy metals in tea at trace levels has gotten a lot of attention since theyare linked to health.Methodology: To gather data on the prevalence of heavy metals in black tea, a basketsurvey was done in the tea markets in Baghdad.Results: A total of 36 black tea samples were examined for heavy metals. Theaverages of heavy metals levels were Pb (1.92±0.67mgkg -1) , Cu (9.4±1.51mgkg -1) , Zn(13.625±1.82mgkg -1 ), and Fe (81.15±18.52 mgkg -1 ,). According to the results, all heavymetals levels were acceptable range and no risk possible following tea consumption.Conclusion: The information in this database could be used to set tolerance limits forother heavy metals in tea.Aim: The aim of this work is to evaluate the levels of heavy metals in back tea.

Heavy Metals in Tea and Their Adverse Effects on Mother and Fetal Outcome

This study aimed to analyze the adverse effects of heavy metals in tea on pregnant mothers and fetal outcomes, using Camellia sinensis tea as a more common beverage after water. The tea constituents are flavonoids containing catechins, which are primary polyphenols recognized as having a strong anti-oxidant activity preventing cellular damage by free radicals. During pregnancy, excessive tea intake negatively impacts the newborn. Tea constituents and their contamination have gained attention as heavy metal contamination exceeds its critical concentrations in tea infusions which may cause adverse effects on both mother and fetus. A total of 400 pregnant women participated in the present study. A cross-sectional study was conducted at the department of Physiology of University of Sindh in collaboration with the Department of gynecology and obstetrics of Liaquat University of Medical and Health Sciences (LUMHS), Jamshoro, from September 2018 to August 2020. Selected pregnant women were informed and gave written consent. Chemical analysis of maternal blood was conducted at the National Centre of Excellence in Analytical Chemistry, University of Sindh. The statistical data were analyzed using SPSS v 21.0 (IBM incorporation, USA). The student`s and Person tests for correlation were applied, presenting the results as mean ± standard deviation (SD). Statistical significance difference was calculated at 95% (p ≤ 0.05). The results of maternal parameters such as age, marital age, maternal height, body temperature, respiratory rate, and diastolic pressure had no significant difference. Simultaneously, gestational age, neck circumference, gestational weight gain, and systolic blood pressure had significant differences between pregnant tea and non-tea drinkers. Iron, Total iron-binding capacity (TIBC), and Ferritin also showed statistically significant differences at p &lt; 0.0001. In the present study, the fetal weight positively correlated with aluminum, lead, mercury, and zinc and negatively correlated with copper and cadmium. Foot length showed a positive correlation with aluminum, copper, lead, cadmium, mercury, and zinc; the chest circumference showed a negative correlation with aluminum and copper.

Geochemical characteristics of heavy metals of bedrock, soil, and tea in a metamorphic rock area of Guizhou Province, China.

Through field surveys, sampling, and laboratory experiments, the content, enrichment, and migration characteristics of heavy metals in the rock-soil-tea system in the Guizhou metamorphic rock area were analyzed herein. The results show that the As and Hg contents in metamorphic sandstone in the study area are higher than those in slate, while the Mn, Zn, Pb, and Ni contents in slate are higher. The content of heavy metals in the sandstone of the Jialu formation of the Xiajiang group in Neoproterozoic is the highest, and that of the slate of the Fanzhao formation is the lowest. The content of As in the rock samples in the study area is higher than that in the Epicontinental crust, while Cd is found to be deficient. The heavy metals at some soil points exceed the standard, but this does not affect the growth and development of tea. The content of heavy metals in most tea is lower than the safety limit standards, and the THQ value is less than 1, indicating that the heavy metals in tea in Guizhou metamorphic rock areas pose no concern for human health. In the metamorphic rock distribution areas of Guizhou, tea does not enrich As, Cr, Hg, and Pb in soil, but enriches Mn, Cu, Ni, and Zn to varying degrees, with the enrichment of Mn being the strongest.

Prediction and Health Risk Assessment of Copper, Lead, Cadmium, Chromium, and Nickel in Tieguanyin Tea: A Case Study from Fujian, China.

Heavy metal is widespread in food and the environment due to multiple origins, raising concerns over their persistent potential health risks. Contamination of multiple heavy metals in tea leaves is frequently reported. However, the dietary exposure risk that heavy metals in Tieguanyin tea (a famous type of oolong tea,) pose to different subpopulations has not been explored. In this study, contaminations of five heavy metals (Cu, Pb, Cr, Cd, and Ni) of concern in Tieguanyin tea were monitored, then the related health risk was assessed for six different subpopulations based on tea brewing experiments and a previous consumption survey. Results show that the mean levels found were as follows: 8.18 mg/kg (Cu), 0.84 mg/kg (Pb), 0.51 mg/kg (Cr), 0.04 mg/kg (Cd), and 1.90 mg/kg (Ni), respectively, and their transfer rates during tea brewing varied within 10.2–70.4%. All estimated daily intakes of individual targeted elements via Tieguanying tea consumption were far below their corresponding tolerable limits. The adjusted hazard index value ranged from 1.1 × 10−2 to 1.7 × 10−2, indicating that exposure to these five elements via drinking Tieguanyin tea would not pose significant non-cancer risks for six subpopulations under the current consumption habit. In addition, the carcinogenic risks associated with heavy metals (Pb, Cd, and Cr) were acceptable because no total cancer risk values exceeded the 10−4 threshold. However, in order to improve consumer protection, we still suggest that considerable attention should be paid to Pb, Ni, and Cd because of their high concentration in infusion, high extraction rate, and major carcinogenic risk contribution, respectively.

Assessment of heavy metals in infused tea marketed in Riyadh, Saudi Arabia, using inductively coupled plasma-mass spectrometry: human health risk assessment

ABSTRACT The present study aims to investigate the levels of some heavy metals: Arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg) in infused tea consumed in Riyadh, Saudi Arabia, and their potential health risk. Inductively coupled plasma mass spectrometry (ICP-MS) was used to assay the concentration of heavy metals in tea samples, after microwave acid digestion. This study was carried out on 25 brands of tea purchased from Riyadh city supermarkets. The validation of the proposed method was developed by measuring different parameters e.g. accuracy, precision, linearity, the lower limit of quantification (LLOQ), the lower limit of detection (LLOD). The method was examined for the determination of As, Cd, Pb and Hg in spiking samples with good accuracy and precision. The average daily intake (ADI), the hazard quotient (HQ), the total hazard quotations (THQs), and hazard index (HI) of the investigated metals were used for the assessment of health risks associated with the intake of metals. The mean concentration of heavy metals in infused tea were found in the range of 0.008–0.445, 0.0097–0.044, 0.012–2.379 and 0.0053–0.044 mg/kg for As, Cd, Pb and Hg, respectively. The results revealed that the concentration of As, Cd and Hg metals in all samples of infused tea was considered in the standard range, whereas the concentration of Pb exceeded the maximum concentration limit presented by World Health Organization (WHO). Therefore, the continuous monitoring of the concentration of heavy metals in tea is essential on a regular basis.

Detection of Changes in Total Antioxidant Capacity, the Content of Polyphenols, Caffeine, and Heavy Metals of Teas in Relation to Their Origin and Fermentation

Tea (Camellia sinensis) is widely sought for beverages worldwide. Heavy metals are often the main aims of the survey of teas, given that the use of agricultural fertilization is very frequent. Some of these may affect the content of bioactive compounds. Therefore, in this study, we analyzed fermented and non-fermented teas of a single plant origin from Japan, Nepal, Korea, and China, and described mutual correlations and changes in the total antioxidant capacity (TAC), and the content of polyphenols (TPC), caffeine, and heavy metals in tea leaves, in relation to the origin and fermentation process. Using UV-VIS spectrophotometry and HPLC-DAD, we determined variations in bioactive compounds’ content in relation to the fermentation process and origin and observed negative correlations between TAC and TPC. Heavy metal content followed this order: Mn > Fe > Cu > Zn > Ni > Cr > Pb > Co > Cd > Hg. Given the homogenous content of these elements in relation to fermentation, this paper also describes the possibility of using heavy metals as determinants of geographical origin. Linear Discriminant Analysis showed an accuracy of 75% for Ni, Co, Cd, Hg, and Pb, explaining 95.19% of the variability between geographical regions.

Occurrence, accumulation, and risk assessment of trace metals in tea (Camellia sinensis): A national reconnaissance

Accumulation of potentially toxic elements in soil and tea leaves is a particular concern for tea consumers worldwide. However, the contents of potentially toxic elements and their potential health and ecological risks in Chinese tea gardens have rarely been investigated on the national scale. In this study, we collected 225 paired soil and tea plant samples from 45 tea gardens in 15 provinces of China to survey the current risk of potentially toxic element accumulation in Chinese tea gardens. The results suggest that the average contents of most trace metals in rhizosphere soils meet the risk control standard for agricultural land in China. However, the mean contents of As, Cr, Cd, Zn, Cu, and Ni in rhizosphere soils were 1.94, 2.14, 1.23, 1.15, 1.18, and 1.19 times their corresponding background soil values in China. Cd had the highest geo-accumulation index, followed by As, Zn, Cr, Ni, Cu, Pb, and Mn in rhizosphere soils. Nearly 2.22% and 4.44% of soils were moderately to heavily contaminated with As and Cd, respectively. The risk index ranged from 18.0 to 292, with an average value of 90.0, indicating low to moderate ecological risk in Chinese tea gardens. This is the first national-scale reconnaissance of trace metals in tea across China. Our findings provide a useful reference for ensuring the quality and safety of tea production and mitigating the risk of toxic element accumulation in tea.

Screening for Heavy Metals in Tea Leaves from Bangladesh Using X-Ray Fluorescence

Trace metal contamination is a global health issue. This study evaluated boxed and loose-leaf tea from Bangladesh using a Handheld X-ray Fluorescence (XRF) analyzer for lead and other metals to rapidly screen tea as a potential hot spot of heavy metal exposure. Of the 33 elements measured, several priority pollutants were below the limit of detection (LOD) in all samples, including lead (LOD 2.17 mg/kg) and arsenic (LOD 1.68 mg/kg). Loose-leaf tea samples had higher copper (1.5-fold), zinc (1.3-fold), and manganese (1.8-fold) concentrations compared to boxed tea. Estimated daily intake (EDI) of lead from tea was calculated using three assumed extractability levels, 20%, 50%, and 100%, and assuming the lead concentration was at the LOD. The EDI for lead ranged from 0.008 µg/kg/bw day to 0.041 µg/kg/bw for adult males and 0.010 µg/kg/bw day to 0.049 µg/kg/bw day for adult females. Based on these tested samples, tea is not likely a primary source of lead exposure in the two sampled areas, Sirajdikhan and Pabna. Future research can evaluate potential processing steps for why some metals were higher in loose-leaf tea compared to boxed tea, including copper, zinc, and manganese. Other potential lead sources could be tested in the tea preparation process, including water sources and dishware used to prepare and consume the tea.

Geological load and health risk of heavy metals uptake by tea from soil: What are the significant influencing factors?

As one of the most popular beverages around world, factors influencing transfer of heavy metals from soil to tea leaves is crucial to investigate and assess health risk through tea drinking. Parent material (PM), soil and tea samples from Anhui province, typical tea producing area in China were collected in this study. To find out distribution characteristics of heavy metals in tea and soil, and influencing factors for transfer process, variables of plantation factors, soil properties and geological background were taken into account. The results showed that weathering pedogenic process could be the main release source of heavy metals in soil under the acid environment for tea growth. More than 75% of soil Cd, Hg, Pb and Zn exceeded background. However heavy metals in tea samples were below the limits of China, WHO and EU standards. Soil organic matter and redox process influenced the distribution and transfer of As, Pb, Cd and Hg in soil and tea. While geochemical behaviours of Cr, Cu, Ni and Zn were mainly related to soil pH and iron oxides in tea garden. The method of classification and regression trees (CART) showed clones of tea type, bedrock type, soil texture, soil organic and fertilizer application were identified as the main factors influencing transfer factors of heavy metals from soil to tea. The specific types of tea grown in the soil with sandy clay and bedrock of granite/granodiorite and shale should be given more monitoring. The non-carcinogenic hazard quotients (HQ) and cancer risk (Risk) through tea drinking were primarily caused by Pb and Cd respectively. To reduce the potential health risk from tea, application of organic and/or compound fertilizer were thought to be the effective management strategy for tea plantation.

Accumulation of heavy metals in tea leaves and soils: a case of Sri Lankan tea plantation

Accumulation of heavy metals in tea leaves and soils: a case of Sri Lankan tea plantation

Accumulation of heavy metals in tea leaves and soils: a case of Sri Lankan tea plantation

Accumulation of heavy metals in tea leaves and soils: a case of Sri Lankan tea plantation

Evaluation of heavy metal concentrations in black tea and infusions in Neyshabur city and estimating health risk to consumers

ABSTRACT Heavy metal pollution is one of the environmental problems and one of the critical concerns of food hygiene. Consumption of tea as a pleasant drink and food habit is common among Iranians.The presence of these metals in tea can be an essential source of contamination in food.This study aimed to investigate the levels of lead, chromium, nickel, cadmium, aluminium, and arsenic in samples of dry black tea and Infusionsin the market of Neyshabur in 2019.Samples were digested with nitric acid and perchloric acid, and the concentration of the desired metals was read by the spectrometric method.All experiments were performed in 3 replications.Then, the Provisional Tolerable Daily index (PTDI) and Hazard Quotient (HQ) levels of heavy metal intakes were calculated to estimate the health hazard for consumers.The Mean concentrations of Pb, Cr, Ni, As,Al, and Cd in the tea leavesand Infusions were 1.96, 3.05, 3.68, 0.048, 2.195, 0.03 mg/kg and 0.07, 0.17, 0.88, 0.03, 0.53, 0.003 mg/kg, respectively.The results also showed that the target hazard quotient (THQ) for Cr and Alis more than one. In the samples of dry tea and their Infusions, concentrations ofCrand Alwere exceeded from Iran’s Ministry of Health and WHO guidelines. The two elements of Ni and Pb are more than the Iranian National Standards Organisation’sinstructions.HQ values for chromium and aluminium obtainedhigher than one, which indicatedadverse effectson tea consumers’ health. Therefore, continuous monitoringis essential to determine the toxic metals’concentrationsin tea samples.

Distribution, accumulation, and potential risks of heavy metals in soil and tea leaves from geologically different plantations.

Risk assessment regarding heavy metals in tea is crucial to ensure the health of tea customers. However, the effects of geological difference on distribution of heavy metals in soils and their accumulation in tea leaves remain unclear. This study aimed to estimate the impacts of geological difference on distribution of cadmium (Cd), lead (Pb), thallium (Tl), mercury (Hg), arsenic (As), antimony (Sb), chromium (Cr), nickel (Ni), and manganese (Mn) in soils and their accumulation in tea leaves, and further evaluate their health risks. 22 soils and corresponding young tea leaves (YTL) and old tea leaves (OTL), from geologically different plantations, were sampled and analyzed. Results showed that heavy metals concentrations in soils, derived from Permian limestone and Cambrian weakly mineralized dolomite, were obviously greater than those from Silurian clastic rock. The geological difference controlled the distribution of soil heavy metals to a large extent. Contents of Cd, Tl, and Mn in tea leaves mainly depended on their contents in soils. Soil Hg, Pb, As, and Sb contents may not be the only influencing factors for their respective accumulation in tea leaves. More attentions should be paid to soil acidification of tea plantations to ensure the tea quality security. Target hazard quotients (THQ) of Cd, Pb, Tl, Hg, As, Sb, Cr, and Ni and hazard index (HI) via tea intake were below one, indicating no human health risk. The non-mineralized Silurian area was less at risk of heavy metals accumulation in tea leaves than the Cambrian metallogenic belt and the Permian Cd-enriched zone. This study could provide an important basis to understand and mitigate the potential risks of heavy metals in tea.

Study of Heavy Metals in Teas from Romanian Market

The aim of this study was to determine heavy metals levels in some varieties of tea from the Romanian market. For this purpose, 15 samples of tea of the following assortments were analyzed: green tea, black tea, herb tea and fruit tea. Determination of heavy metals traces was achieved with inductively coupled plasma mass spectrometry (ICP-MS). The quantities of Pb, Hg and Cd from analyzed tea samples were compared with the permissible dose in accordance with the Notice of Scientific Panel on Contaminants in the Food Chain of European Food Safety Authority (EFSA).

Zn, Ni, Mn, Cr, Pb and Cu in soil-tea ecosystem: The concentrations, spatial relationship and potential control

Excessive accumulation of heavy metals in tea has certain health risk to the consumers. To discuss the spatial relationship between heavy metals in tea leaves and soil in a county scale, 74 samples of tea leaves and corresponding subsoil (15–30 cm) were collected in the tea plantations of Lishui, Nanjing, China. The total Zn, Ni, Mn, Cr, Pb and Cu in both tea leaves and soil samples, as well as pH value in soil were analyzed. The results of regression showed that the Mn and Cr in tea leaves were increased when the Mn and Cr in soil were at high levels, and higher pH decreased Zn, Ni, Mn and Cu contents in tea leaves. Moreover, distance to village and metal industry had negative impacts on the Mn level in soil. It is necessary to control the pH of soil in tea plantations which are close to villages or metal industries, as well as, to search more appropriate areas, where are far away from villages or metal industries, to plant tea should be taken into consideration. In addition, 17.57% of the samples have higher concentration of Pb than the maximum limits was found in tea plantation of Lishui. Heavy metals (Cr) standards regarding leafy vegetables is used for reference in this study, as there are no maximum levels of contaminants (MLC) in tea. It is significant to construct a targeted standard of heavy metals contents that could applicable throughout the world for reduce the health risks to the consumers.

Aluminum and Heavy Metal Accumulation in Tea Leaves: An Interplay of Environmental and Plant Factors and an Assessment of Exposure Risks to Consumers.

Environmental and plant factors influence aluminum and heavy metal accumulation in tea leaves. Consumers of tea are not ingesting excessive Al, Mn, Pb, Cd, or Cu. Trackable factors were identified to manage exposure levels.