Conventional Wet Acid Digestion Method Research Articles

Health Risk and Metal Contamination Assessment in Orange (Citrus aurantium) of Pakistan: a Multivariate Study.

Toxic metals (TMs) are serious health hazard and are known to accumulate in fruits, which are consumed by people, owning to their distinct sweet flavor and potential health benefits. In the present study, arsenic (As), lead (Pb), chromium (Cr), copper (Cu), cadmium (Cd), nickel (Ni), and mercury (Hg) were measured by atomic absorption spectrometry (AAS) techniques in orange samples from 11 farmhouses of Sargodha, Pakistan. Principal component analysis (PCA) is a very useful analysis and data-reducing tool. This technique was used to explore the relationship between different metal levels in the oranges. The conventional wet acid digestion method was validated and assured with two (02) certified reference materials NIST-SRM 1515-Apple and (CRM) NIST-1570a Spinach Leaves by recovery test coupled with standard addition procedure. The results showed that Cd and Cr average daily intakes are 0.084 and 0.15mg slightly higher than World Health Organization/Food and Agriculture Organization of the United Nations (WHO/FAO) recommended tolerable daily intake respectively. The assessment of health risk was also carried out in form of total hazard quotient (THQ) and hazard index (HI), indicating three heavy metals (Pb, Cd, and Cr) have significant human health risk potential to consumers while Cu, As, Hg, and Ni have non-significant (THQ < 1) health risks.

Heavy metals contamination in two species of medicinal plants in the Iranian market

ABSTRACT Global threat resulting in heavy metal contamination of medicinal plants is considered a serious concern. The quantitative evaluation of four heavy metals, lead (Pb), cadmium (Cd), zinc (Zn), and copper (Cu), was investigated frequently sold medicinal plants in the markets of Iran. Two medicinal plants, Mentha piperita L., and Zataria multiflora Boiss. were selected from six different herbalists of six districts of Shiraz, Iran. The dissolution of the sample was performed by a conventional wet acid digestion method, and heavy metal levels were determined using Polarograph. Statistical Analysis was used by SPSS.21. According to the achieved results in M.piperita the levels of Zn, Cd, Pb, and Cu were in the range of 2.66 ± 0.76 mg/kg, 0.017 ± 0.009 mg/kg, 0.092 ± 0.069 mg/kg, and 0.237 ± 0.080 mg/kg, respectively. The concentrations of Zn, Cd, Pb, and Cu in Z. multiflora samples were 1.46 ± 0.74 mg/kg, 0.019 ± 0.004 mg/kg, 0.11 ± 0.05 mg/kg, and 0.41 ± 0.17 mg/kg, respectively. There was a correlation between Zn with Cu in our finding (r = 0.9). Based on these results, we found that the concentration of heavy metals in these two medicinal plants was not more than the standard concentration reported for similar plants. It appears that these plants are generally safe in usual doses. The finding of this study can be used to determine standard heavy metals limits in M.piperita and Z.multiflora in future studies.

Symptoms Associated with Low Threshold Lead Poisoning Among Roadside and Organized Panel Beaters in Enugu Metropolis, Nigeria.

Background.There is no safe level of human exposure to lead (Pb). Detecting common early symptoms of low threshold Pb poisoning can help to prevent the damaging effects of higher doses and chronic low dose exposures. Panel beaters or auto body mechanics are exposed to Pb through their occupational duties.Objectives.The present study aimed to determine common early symptoms associated with lower threshold Pb poisoning among roadside and organized panel beaters in Enugu Metropolis, Nigeria.Methods.This was a comparative cross-sectional study of 428 panel beaters in Enugu metropolis. A multi-stage sampling method was used to select 214 respondents each from the roadside and organized sectors. A semi-structured interviewer-administered questionnaire was used for data collection. Samples were collected under aseptic procedures. Blood Pb samples were extracted using the conventional wet acid digestion method and analyzed using a flame atomic absorption spectrometer (wavelength 283.3 nm). Comparative analysis was performed using the chi – square and Mann-Whitney U test. Statistical significance was set at P < 0.05.Results.Median Pb levels were 3.0 ug/dL and 16.0 ug/dL among roadside and organized panel beaters, respectively, with a significant difference. Numbness of limbs (P = 0.010) and fatigue (χ2 = 5.294, P = 0.023) were found to be associated with roadside panel beaters, while weakness (χ2 = 6.185, P = 0.019) and fatigue (χ2 = 4.206, P = 0.046) were associated with organized panel beaters.Conclusions.Nonspecific constitutional symptoms were common early symptoms of Pb poisoning irrespective of workplace occupational practices. These symptoms will help in early detection and control of occupational lead exposures.Participant Consent.ObtainedEthics Approval.Ethics approval was obtained from the Health Research Ethics Committee of the University of Nigeria Teaching Hospital, Ituku Ozalla, Enugu.Competing Interests.The authors declare no competing financial interests.

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.

Assessment of Zinc, Lead, Chromium, and Cobalt in Commonly Consumed Herbal Medicines in Sindh, Pakistan.

Herbal medicines are widely consumed by the people of Pakistan for the treatment of various diseases. In the current study, quantitative assessment of four heavy metals namely zinc, lead, chromium, and cobalt was carried out in forty commonly consumed herbal medicines purchased from the markets of Khairpur and Sukkur, Pakistan. The 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. Varied concentrations of metals were observed in different herbal medicines. The levels of Zn, Pb, Cr, and Co were in the range of 7.05-87.5 ppm, 5.62-44.9 ppm, 3.16-14.1 ppm, and 5.69-9.88 ppm, respectively. The findings of our study were compared with the WHO maximum permissible limits of these metals and it was observed that most of the analyzed samples exceeded the permissible levels. Keeping in view the levels of these metals in the selected herbal medicines, the prolonged intake of these drugs might be hazardous for human beings.

Simultaneous determination of Fe and Ni in guarana (Paullinia cupana Kunth) by HR-CS GF AAS: Comparison of direct solid analysis and wet acid digestion procedures

Direct solid sampling method was compared with the conventional wet acid digestion method to simultaneously assay iron and nickel in guarana by high-resolution continuum source graphite furnace atomic absorption spectrometry. Measurements were done with the secondary lines of Fe and Ni. Four digestion procedures using mixtures of HNO3 and H2O2 (procedure A), HNO3 and HCl (procedure B), HNO3, HCl and H2O2 (procedure C) and HNO3, H2SO4 and H2O2 (procedure D) were evaluated. All tested procedures provided quantitative recoveries for Ni, whereas a good recovery for Fe was obtained only with procedure D. Procedure D was chosen for the digestion of all guarana samples. The limit of detection for the direct solid sampling method was 1.004 μg g−1 for Fe and 0.022 μg g−1 for Ni, and the precision ranged from 3.5–20.0% and 2.8–8.0% for Fe and Ni, respectively. Method accuracy was evaluated by statistical comparison between analyte concentrations, obtained by measurements in the solid samples by the proposed method and after the digestion of the samples by procedure D. The validation of the analytical results obtained for the solid and the digested sample was performed by Energy Dispersive X-Ray Fluorescence.

Evaluation of Toxic and Essential Metals in Some Selected Chewing Food Products and their Daily Intake by the Population of Karachi, Pakistan

The present study focused on different brands of chewing food products which containing some toxic metals (TMs) and essential metals and these samples were analyzed to determine the levels of some toxic metals (Pb, Cd, Ni, Cr and Mn) and essential metals (Ca, Cu, Fe, K, Mg, Na and Zn). The samples of gutka (100), sweet supari (63), sweet paan (16) and paan masala (21) were randomly collected from different shops of Karachi, Pakistan. The validity of conventional wet acid digestion method (CAD) was assessed by analyzing two certified reference materials (CRM) Virgina tobacco leaf (CTA-VTL-2) and Bovine liver (1577b) and standard addition recovery test. The limit of detections (LODs, n=10) of the method were found to be 0.144, 14.4, 8.89, 2.76, 4.06, 15.3 and 2.99, 22.9, 9.97, 4.54, 1.89, 1.76 µg L -1 for Ca, Cu, Fe, K, Mg, Na, Zn, Cd, Cr, Mn, Ni and Pb, respectively. The CAD method was successfully applied to real samples for the determination of toxic and essential metals.

Interaction between essential elements selenium and zinc with cadmium and mercury in samples from hypertensive patients.

The abnormal metabolism of metal ions plays an important role in health and disease conditions; hence, the studies about them have received much interest. The objective of this study was to evaluate the association between trace and toxic elements zinc (Zn), cadmium (Cd), selenium (Se), and mercury (Hg) in biological samples (scalp hair, blood, and urine) of hypertensive patients (n = 257), residents of Hyderabad, Pakistan. For comparison purpose, the biological samples of age-matched healthy controls were selected as referents. The concentrations of trace and toxic elements were measured by atomic absorption spectrophotometer prior to microwave-assisted acid digestion. The validity and accuracy of the methodology was checked using certified reference materials and by the conventional wet acid digestion method. The recovery of all studied elements was found in the range of 96.4-99.1 % in certified reference materials. The results of this study showed that the mean values of Cd and Hg were significantly higher in scalp hair, blood, and urine samples of hypertensive patients than in referents (P < 0.001), whilst the concentrations of Zn and Se were lower in the scalp hair and blood, but higher in the urine samples of hypertensive patients. The deficiency of Zn and Se and the high exposure of toxic metals may be synergistic with risk factors associated with hypertension.

Distribution of Potassium, Calcium, Magnesium, and Sodium Levels in Biological Samples of Pakistani Hypertensive Patients and Control Subjects

The abnormal metabolism of metal ions plays an important role in health and disease conditions, and studies about them have been attracting significant interest. The aim of our study was to assess the essential minerals (calcium (Ca), magnesium (Mg), potassium (K), and sodium (Na)) in biological samples (scalp hair, blood, urine) of 387 hypertensive males and females, age 30-60 years, in an urban population together with 439 non-hypertensive subjects of same age group and residential areas. The element concentrations were measured by means of an atomic absorption spectrophotometer after microwave-induced acid digestion. The validity and accuracy was checked by conventional wet acid digestion method and using certified reference materials. The overall recoveries of all elements were found in the range of 99.1-99.9% of certified values. The results indicated significantly lower levels of Ca, Mg, and K in the biological samples (blood and scalp hair) of hypertensive patients, when compared to controls of both genders. The level of Na was found to be high in biological samples of hypertensive patients as compared to controls. The deficiency of Ca, Mg, and K may be synergistic with risk factors associated with hypertension. These data present guidance to clinicians and other professionals who will be investigating the deficiency of essential micronutrients in biological samples (scalp hair and blood) of hypertensive patients.

Distribution of arsenic, cadmium, lead, and nickel levels in biological samples of Pakistani hypertensive patients and control subjects.

The abnormal metabolism of metal ions plays an important role in health and disease conditions, and studies about them have been attracting significant interest. The aim of our study was to assess the toxic elements arsenic (As), cadmium (Cd), nickel (Ni), and lead (Pb) in biological samples (scalp hair, blood, urine) of 387 hypertensive males and females, aged between 30 and 60 years, from an urban population together with 439 non-hypertensive subjects, of the same age group and residential areas. The element concentrations were measured by means of an electrothermal atomic absorption spectrophotometer after microwave-induced acid digestion. The validity and accuracy was checked by conventional wet acid digestion method and using certified reference materials. The overall recoveries of all elements were found in the range of 96.8 - 99.4% of certified values. The results indicated significantly higher levels of As, Cd, Ni, and Pb in the biological samples (scalp hair, blood and urine) of hypertensive patients, when related to controls of both genders. The high exposure of toxic elements may be synergistic with risk factors associated with hypertension. These data present guidance to clinicians and other professionals who will be investigating the toxicity of heavy elements in biological samples (scalp hair and blood) of hypertensive patients.

Evaluation of chromium and manganese in biological samples (scalp hair, blood and urine) of tuberculosis and diarrhea male human immunodeficiency virus patients.

The consequence of trace elements deficiency has been associated with an increased risk of human immunodeficiency virus type 1 (HIV-1) disease progression and mortality. This study examined the association between high concentrations of chromium (Cr) and manganese (Mn) in scalp hair, blood, and urine and opportunistic infections in hospitalized patients with the acquired immune deficiency syndrome (AIDS). The study was performed on 62 male HIV+ patients (HIV-1) from different cities of Pakistan. The patients were divided in two groups according to secondary infections (tuberculosis, diarrhea, or high fever). The biological samples (scalp hair, blood and urine) were collected from AIDS patients, and for comparative study 120 healthy subjects (males) of same age group (31 - 45 years), socio-economic status, localities, and dietary habits were also included. The elements in the biological samples were analyzed by electrothermal atomic absorption spectrophotometry after microwave-assisted acid digestion. The validity and accuracy of the methodology was checked by using certified reference materials (CRMs) and with the values obtained by conventional wet acid digestion method on the same CRMs. The results indicated significantly lower concentrations of Cr and Mn in the biological samples (scalp hair, blood, and urine) of male HIV-1 patients, compared with control subjects. It was observed that the lower levels of these trace elements may be predictors for secondary infections in HIV-1 patients. There was a significant decrease in mean values of Cr and Mn in whole blood and scalp hair, whilst higher concentrations were observed in urine samples of the three groups of AIDS patients as compared to a controlled healthy male group (p < 0.001). Low Cr and Mn levels may be due to increased Cr and Mn losses. These data present guidance to clinicians and other professional investigating deficiencies of Cr and Mn in biological samples of AIDS patients.

Efficiency of Extraction of Trace metals from Blood samples using Wet Digestion and Microwave Digestion Techniques

The efficiency of extraction of trace metals using conventional wet acid digestion method (CDM) and microwave induced acid digestion method (MWD) was determined by recovery experiments. The high percentage recoveries obtained from microwave induced acid digestion method make it to be a more efficient method than the conventional wet acid method. The conventional wet acid digestion method is time consuming while the MWD method saves time, less than four minutes are required to complete the digestion of the biological samples in this study.

Distribution of Copper, Iron, and Zinc in Biological Samples of Pakistani Hypertensive Patients and Referent Subjects of Different Age Groups

The abnormal metabolism of metal ions plays an important role in health and disease conditions, and studies about them have been attracting significant interest. The aim of our study was to assess the trace metals (copper (Cu), iron (Fe), and zinc (Zn)) in biological samples (scalp hair, blood, urine) of 387 hypertensive males and females, age range 30 - 60 years, from an urban population and 439 non-hypertensive subjects of same age group and residential areas. The element concentrations were measured by means of an atomic absorption spectrophotometer after microwave-induced acid digestion. The validity and accuracy was checked by conventional wet acid digestion method, using certified reference materials. The overall recoveries of all elements were found in the range of 95.2 - 98.7 % of certified values. The results indicated significantly lower levels of Cu, Fe, and Zn in the biological samples (blood and scalp hair) of hypertensive patients when compared to referents of both genders while the levels of these elements was found to be high in urine samples of hypertensive patients as compared to referents. The deficiency of Cu, Fe, and Zn may be synergistic with risk factors associated with hypertension. These data present guidance to clinicians and other professionals who will be investigating the deficiency of essential micronutrients in biological samples (scalp hair, serum, and blood) of hypertensive patients.

Evaluation of Status of Arsenic, Cadmium, Lead and Zinc Levels in Biological Samples of Normal and Arthritis Patients of Age Groups (46 - 60) and (61 - 75) Years

Arthritis is a chronic inflammatory disease resulting in inflammation of diarthrodial joints (particularly joints of hands, wrists, feet, knees, ankles, and shoulders), manifested by swelling and functional impairment. This study was designed to evaluate the levels of the toxic elements arsenic (As), cadmium (Cd), and lead (Pb) and correlate those with the essential trace element zinc (Zn) in biological samples (scalp hair, blood, and urine) of arthritis patients, in two age groups (46 - 60 and 61 - 75) of both genders. For comparison purposes all three biological samples were collected from gender- and age-matched non-arthritic subjects as referents. The As, Cd, and Pb in biological samples were analysed by electrothermal atomic absorption spectrometry, prior to microwave assisted acid digestion. The level of Zn was determined by flame atomic absorption spectrometry. The validity and accuracy of the methodology was checked by using Certified Reference Materials (CRM) from the Community Bureau of Reference (BCR) of the Commission of the European Community and with those values obtained by conventional wet acid digestion method on the same CRMs. The results of this study showed that the mean values of As, Cd, and Pb were higher in blood, scalp hair, and urine samples of arthritis patients as compared to those values obtained in age-matched referent subjects. The concentration of Zn was lower in the biological samples of rheumatoid arthritis patients of both genders with respect to non-arthritic subjects. The urinary levels of the elements studied were found to be higher in the arthritis patients than in the age-matched healthy referents (p < 0.001). An inverse correlation was observed between Zn and toxic elements in biological samples of arthritis patients (r = 0.612 - 0.754). Intake of certain antioxidant micronutrients, particularly a zinc supplement, may protect against the development of rheumatoid arthritis.

&#x0D; Evaluation of Chromium, Cobalt and Manganese in Biological Samples (Scalp Hair, Blood, and Urine) of Pakistani Viral Hepatitis (A–E) Patients and Controls

The aim of the present study was to compare the level of chromium (Cr), cobalt (Co), and manganese (Mn) in biological samples (blood, urine, and scalp hair) of patients suffering from different types of viral hepatitis (A, B, C, D, and E; n = 521) of both genders, ages ranging from 31 - 45 years. For comparative study, 255 age-matched control subjects of both genders residing in the same city were selected as referents. The digests of all biological samples were analysed for Cr, Co, and Mn by electrothermal atomic absorption spectrometry (ETAAS). The validity and accuracy of the methodology was checked by using certified reference materials (CRMs) and compared with those values obtained by conventional wet acid digestion method on same CRMs. The results of this study showed that the mean values of Cr, Co, and Mn were higher in blood and scalp hair samples of hepatitis patients than in age-matched control subjects. The urinary levels of these elements were found to be higher in the hepatitis patients than in the age-matched healthy controls (p <0.001). These results are consistent with literature-reported data, confirming that the overload of these trace elements can directly cause lipid peroxidation and eventually hepatic damage.

Interaction between essential trace and toxic elements in the scalp hair samples of smokers and alcohol user diabetics

In the present study, trace and toxic elements were determined in the Scalp Hair (SH) samples of patients diagnosed with diabetes mellitus (DM) who were smokers and habitual alcohol drinkers living in Dublin, Ireland. The concentrations of elements were measured by inductively coupled plasma atomic emission spectrophotometer after microwave-assisted acid digestion. The validity and accuracy of the methodology was checked using Certified Reference Material (CRM) (NCS ZC 81002b) and by the conventional wet acid digestion method on the same CRM. The results of this study showed that the mean values of cadmium, copper, iron, nickel and lead were significantly higher (P < 0.001), in scalp hair samples of diabetic patients as compared to referents of both gender. While the smokers and alcohol drinker referents and DM patients have two to three time higher values of these elements than those subjects who were not smokers and teetotallers. The concentrations of zinc, chromium and manganese were lower in the scalp hair samples of diabetic patients as compared to referents. The deficiency of zinc, chromium and manganese, while the high exposure of cadmium, lead and nickel, as a result of cigarette smoking and alcohol consumption, may be synergistic with risk factors associated with diabetes.

A Comparison of Microwave and Conventional Wet Acid Digestion Method for the Determination of Mercury in Coal and Coal Ash

Mercury in coal and coal ash samples was determined by atomic fluorescence spectrometry after microwave digestion. The validity of the method was studied by spike recovery tests and by analyzing certified reference material. The results obtained for mercury in coal and coal ashes were generally in good agreement with that of the wet digestion method. Moreover, microwave methods generally permitted to reduce considerably the digestion time. Furthermore, the mercury results obtained for coal samples by different acid mixtures microwave method provided valuable information for identifying the modes of occurrence of mercury in coal.

Interaction Between Zinc, Cadmium, and Lead in Scalp Hair Samples of Pakistani and Irish Smokers Rheumatoid Arthritis Subjects in Relation to Controls

The incidence of rheumatoid arthritis (RA) has been associated with cigarette smoking. The aim of our study was to assess the trace essential and toxic metals, cadmium (Cd), lead (Pb), and zinc (Zn), in scalp hair samples of 32 Irish and 46 Pakistani smokers and non-smokers RA male patients with age range 42-56 years. For comparison purpose, the scalp hair samples of 27 Irish and 55 Pakistani non-RA male subjects of the same age group were collected. The concentrations of trace and toxic elements were measured by inductive coupled plasma atomic emission spectrophotometer and atomic absorption spectrophotometer prior to microwave-assisted acid digestion. The validity and accuracy of the methodology was checked using certified reference materials and using conventional wet acid digestion method on the same certified reference materials (CRMs). The recovery of all studied elements was found to be in the range of 97.5-99.7% of certified reference values of CRMs. The results of this study showed that the mean values of Cd and Pb were significantly higher in scalp hair samples of both smoker and non-smoker RA patients than in referents (P < 0.001), whereas the concentration of Zn was lower in the scalp hair samples of smokers and non-smokers rheumatoid arthritis patients. The deficiency of Zn and the high exposure of Cd and Pb as a result of cigarette smoking may be synergistic risk factors associated with rheumatoid arthritis.

A Green Analytical Method Using Ultrasound in Sample Preparation for the Flow Injection Determination of Iron, Manganese, and Zinc in Soluble Solid Samples by Flame Atomic Absorption Spectrometry

A simple and rapid analytical method was developed for the determination of iron, manganese, and zinc in soluble solid samples. The method is based on continuous ultrasonic water dissolution of the sample (5–30 mg) at room temperature followed by flow injection flame atomic absorption spectrometric determination. A good precision of the whole procedure (1.2–4.6%) and a sample throughput of ca. 25 samples h–1 were obtained. The proposed green analytical method has been successfully applied for the determination of iron, manganese, and zinc in soluble solid food samples (soluble cocoa and soluble coffee) and pharmaceutical preparations (multivitamin tablets). The ranges of concentrations found were 21.4–25.61 μg g−1 for iron, 5.74–18.30 μg g−1 for manganese, and 33.27–57.90 μg g−1 for zinc in soluble solid food samples and 3.75–9.90 μg g−1 for iron, 0.47–5.05 μg g−1 for manganese, and 1.55–15.12 μg g−1 for zinc in multivitamin tablets. The accuracy of the proposed method was established by a comparison with the conventional wet acid digestion method using a paired t-test, indicating the absence of systematic errors.

Association between essential trace and toxic elements in scalp hair samples of smokers rheumatoid arthritis subjects

The incidence of rheumatoid arthritis (RA) has been increased among people who possess habit of tobacco smoking. In the present study, zinc (Zn), copper (Cu), manganese (Mn), lead (Pb) and cadmium (Cd) were determined in scalp hair samples of smokers and nonsmokers RA patients, residents of Dublin, Ireland. For comparison purposes scalp hair samples of age and sex matched healthy smokers and nonsmokers were also analyzed. The concentrations of understudied elements were measured by inductive coupled plasma atomic emission spectrophotometer, prior to microwave assisted acid digestion. The validity and accuracy of methodology was checked using certified reference material (NCS ZC 81002b) and by the conventional wet acid digestion method on the same certified reference material and on real samples. The mean hair Zn, Cu and Mn contents were significantly lower in smokers and nonsmokers RA patients as compared to healthy individuals (p = 0.01–0.001). Whereas the concentrations of Cd and Pb were significantly higher in scalp hair samples of RA patients of both group (p < 0.001). The referent smokers have high level of Cd and Pb in their scalp hair samples as compared to those had not smoking tobacco (p < 0.01). The ratio of Cd and Pb to Zn, Cu and Mn in scalp hair samples was also calculated. The Cd/Zn ratio was higher in smoker RA patients with related to nonsmoker RA and referents. This study is compelling evidence in support of positive associations between toxic elements, cigarette smoking, deficiency of essential trace elements and risk of arthritis.