Int J Pharm Pharm Sci, Vol 7, Issue 5, 233-236Original Article
EVALUATION OF THE PRESENCE OF THE HEAVY METAL NICKEL IN SAMPLES OF TOBACCO SNUFF (NICOTIANA TABACUM) IN NIGERIA
ADOGU POU1, ABUAH O2, ENYE JC2, CHINEKE HN3, EGENTI BN4
1Department of Community Medicine NnamdiAzikiwe University Teaching Hospital, Nnewi, Nigeria, 2Faculty of Pharmacy Madonna University Elele Nigeria, 3Department of Community Medicine Imo State UniversityTeaching Hospital,Orlu Nigeria, 4Department of Community Medicine, University of Abuja Teaching Hospital, Abuja, Nigeria
Email: prosuperhealth@yahoo.com
Received: 14 Feb 2015 Revised and Accepted: 10 Mar 2015
ABSTRACT
Objective: Tobacco snuffs a finely ground dark brown coloured powder obtained from dried pulverized leaves of tobacco plant Nicotianatabaccum is commonly used among Nigerians. Since the nickel content and its health implications are not known to have been studied, this study evaluates the presence of this heavy metal in some samples of tobacco snuff obtained from four geopolitical zones of Nigeria.
Methods: The study was conducted using thirty samples of tobacco snuff obtained from different parts of Nigeria. The samples were tested for the presence of the heavy metal Nickel by Atomic Absorption Spectrometry.
Results: All the samples contain the heavy metal nickel. Nickel concentration in the studied samples ranged from 0.0003–0.0011 μmol/g, with the highest concentration found in the sample number 3 and 22 only.
Conclusion: Tobacco snuff samples sourced from various geopolitical zones of Nigeria are highly contaminated with the heavy metal Nickel.
Keywords: Evaluation, Nickel, Tobacco snuff, Nigeria.
INTRODUCTION
Tobacco snuff, a form of smokeless tobacco, is a finely ground dark brown dry and pulverized leaves of the tobacco plant, Nicotianatabaccum [1]. The dry tobacco snuff is usually sniffed or swallowed, whereas moist snuff is placed between the lip and the cheek and is slowly absorbed [2].
Heavy metals have the potential to cause harmful health effects when absorbed or inhaled for over a long time as they are easily absorbed through the mucosal membrane [3]. Nickel is a naturally occurring silvery metal found in the earth’s crust. It is considered to be a trace mineral or a micro-mineral which is found in small amounts in the human body and is believed to play a part in the overall health of humans. However, it may be carcinogenic if it accumulates in the body following prolonged use of tobacco snuff [4].
Nickel in the soil often gets to the leaves of the tobacco plant, which has the special affinity for heavy metals [5]. Short term inhalation of nickel may cause sore throat and hoarseness of voice. Ingestion of nickel compounds may cause nausea, vomiting, abdominal pain and diarrhea while long term inhalation of the heavy metal may cause asthma and sinusitis [5]. Physical contact with nickel during preparation of tobacco snuff may result in contact dermatitis [6]. Prolonged exposure by either sniffing or oral use of tobacco snuff could lead to pneumonitis, encephalopathy, acute respiratory distress syndrome, seizures, coma and death. It can also cause cancer of the nasal cavity, lungs and larynx [6].
Nickel is safe in most adults in amount of up to 1 mg/day but doses more than 1 mg/kg could be lethal [7]. When tobacco snuffers take in large amounts of the metal above the recommended 1 mg/day, this can lead to unwanted side effects in the cardiovascular, renal and central nervous systems [7].
The nickel content of tobacco snuff used in Nigeria has never been evaluated with a view to assessing its health implications among consumers. The objective of this study is to determine the amount of the heavy metal nickel in some samples of tobacco snuff obtained from four geopolitical zones of Nigeria.
MATERIALS AND METHODS
Study location
This study was conducted at the pharmacy department of Madonna University Elele, River State Nigeria, between the periods of January 2010 to June 2013.
Apparatuses
Petri dish, Pipette, Spatula, Test tube, Beaker, Stirrer, Digestion bottle, Filter paper, Measuring cylinder, Oven.
Chemicals
Distilled water, De-ionized water, Standard solutions of nickel, Nitric oxide.
Equipment/instruments
| Concentration (mmol/l) | Absorbance @ |
| 0.002 | 0.009 |
| 0.0034 | 0.018 |
| 0.0085 | 0.046 |
| Sample | 0.040 |
Electronic weighing balance (OHAUS Models 2610, Alabama, USA). 2. Atomic Absorption Spectrophotometer Perkin Elmer–5000 with deuterium collector which uses air acetylene Centrifuge (JES BC), (940 Winter Street Waltham, MA, US 02451).
Fig. 1: Calibration curve of nickel concentration against its absorbance
Samples: Thirty (30) samples of tobacco snuff were purchased at several Nigerian open markets inAbia state, Anambra state, Oyo state, Kano state, Suleja, Abuja etc.
The sources of the thirty samples of tobacco snuff from the various geopolitical zones of Nigeria are summarized in the table A below
Table 1: Sources of 30 tobaccos snuff samples from the Nigerian geopolitical zones
| Sample | Geographical area | Town | Type/Name |
| 1 | North Central | Babangida Market Suleja | Foreign Snuff |
| 2 | North Central | Babangida Market Suleja | Medicated |
| 3 | North Central | Kuje Market Abuja | Local |
| 4 | South West | Iseyin Market Oyo | Local |
| 5 | South West | Iseyin Market oyo | Local |
| 6 | South West | Iseyin Market oyo | Local |
| 7 | South West | Iseyin Market Oyo | Local |
| 8 | South West | Agbeni Market Ibadan | Local |
| 9 | South West | Agbeni Market Ibadan | Local |
| 10 | South West | Ileshiro Market Ibadan | Local |
| 11 | South West | Ileshiro Market Ibadan | Local |
| 12 | South East | Main Market Onitsha | UAC & Campbell, Foreign |
| 13 | South East | Main Market Onitsha | Foreign |
| 14 | South East | Main Market Onitsha | Local |
| 15 | South East | Main Market Onitsha | Campbell, KTC & Maxwell (foreign) |
| 16 | South East | Main Market Onitsha | KTC (foreign) |
| 17 | South East | Main Market Onitsha | Broken (local) |
| 18 | South East | Main Market Onitsha | Medicated |
| 19 | South East | Main Market Onitsha | Maxwell (foreign) |
| 20 | North West | Aitiken road, Sab Kano | Local |
| 21 | North West | Yoruba road, Sabongari Kano | Local |
| 22 | North West | Yoruba road, Sabongari Kano | Medicated |
| 23 | South East | Ochanga Market | Medicated |
| 24 | South East | Changer Market | Local |
| 25 | South East | Ahia-ohuru | Local |
| 26 | South East | Ahia-ohuru | Medicated |
| 27 | South East | Umuahia Market | Local |
| 28 | South East | Umuahia Market | Broken |
| 29 | South East | Nnewi | Local |
| 30 | South East | Nnewi | Medicated |
Methods
Study design
A descriptive cross sectional laboratory-based method of research design was employed to profile the presence or absence of the toxic heavy metal nickel in selected 30 samples of tobacco snuff sold in Nigeria.
Sample preparation (wet acid digestion method)
The samples were categorized as samples 1–30 respectively. Some quantity of each sample was put in Petri dishes and 5g of each sample measured using an electronic weighing balance into beakers. Fifty milliliters of diluted 0.1 nitric acid (HNO3) obtained from 65% concentrated HNO was poured into the beakers and then stirred using a stirrer until the sample was totally dissolved. Sample was then transferred into a digestion bottle and placed in an oven at a temperature of 110c for 2 hrs. After 2 hrs the sample from the oven was brought out and allowed to cool at room temperature.
The supernatant layer was removed using a clean filter paper of 110 mm. The sample was then analyzed using the Atomic Absorption Spectrophotometer.
Data analysis
Collated continuous variables were analyzed and presented in tables and fig. for easy appreciation. The difference between mean tobacco concentrations in Nigerian and foreign tobacco snuff samples were determined using the t-test. Level of significance was set at p<0.05.
Ethical consideration
Permission was duly obtained from the Ethics and Research Committee of Madonna University Elele Nigeria before the commencement of the study.
Fig. 2: Nickel concentration intake in four geopolitical regions in nigerian tobacco snuff
Fig. 3: Nickel concentration (μmol/g) in Nigerian vs. foreign smokeless tobacco (X100u), Z-score = 2.78, p<0.05*, *statistically significant
Table 2: Levels of heavy metal-Nickel (μmol/g) found in 5g of each tobacco snuff sample
| Smokeless tobacco product | Nickel (μmol/g) |
| TSS 1 | 0.0003 |
| TSS 2 | 0.0006 |
| TSS 3 | 0.0011 |
| TSS 4 | 0.0006 |
| TSS 5 | 0.0005 |
| TSS 6 | 0.0003 |
| TSS 7 | 0.0006 |
| TSS 8 | 0.0008 |
| TSS 9 | 0.0006 |
| TSS 10 | 0.0005 |
| TSS 11 | 0.0006 |
| TSS 12 | 0.0003 |
| TSS 13 | 0.0008 |
| TSS 14 | 0.0006 |
| TSS 15 | 0.0006 |
| TSS 16 | 0.0010 |
| TSS 17 | 0.0005 |
| TSS 18 | 0.0003 |
| TSS 19 | 0.0005 |
| TSS 20 | 0.0006 |
| TSS 21 | 0.0010 |
| TSS 22 | 0.0011 |
| TSS 23 | 0.0005 |
| TSS 24 | 0.0006 |
| TSS 25 | 0.0006 |
| TSS 26 | 0.0005 |
| TSS 27 | 0.0005 |
| TSS 28 | 0.0005 |
| TSS 29 | 0.0006 |
| TSS 30 | 0.0005 |
| Mean+SD | 0.0006+0.0002 |
| Z-score; p-value (foreign vs local) | 2.11;<0.05* |
Table 3: Daily intake ((μmol/day) of heavy metal nickel through consumption of TSS
| TSS | Ni(μmol/day) | % Violation |
| FAO/WHO ref. value | 0.0034 | - |
| TSS 1 | 0.034 | 1000 |
| TSS 2 | 0.068 | 2000 |
| TSS 3 | 0.120 | 3500 |
| TSS 4 | 0.068 | 2000 |
| TSS 5 | 0.051 | 1500 |
| TSS 6 | 0.034 | 1000 |
| TSS 7 | 0.068 | 2000 |
| TSS 8 | 0.085 | 2500 |
| TSS 9 | 0.068 | 2000 |
| TSS 10 | 0.051 | 1500 |
| TSS 11 | 0.068 | 2000 |
| TSS 12 | 0.034 | 1000 |
| TSS 13 | 0.085 | 2500 |
| TSS 14 | 0.068 | 2000 |
| TSS 15 | 0.068 | 2000 |
| TSS 16 | 0.102 | 3000 |
| TSS 17 | 0.051 | 1500 |
| TSS 18 | 0.034 | 1000 |
| TSS 19 | 0.051 | 1500 |
| TSS 20 | 0.068 | 2000 |
| TSS 21 | 0.102 | 3000 |
| TSS 22 | 0.120 | 3500 |
| TSS 23 | 0.051 | 2000 |
| TSS 24 | 0.068 | 2000 |
| TSS 25 | 0.068 | 2000 |
| TSS 26 | 0.051 | 1500 |
| TSS 27 | 0.051 | 1500 |
| TSS 28 | 0.051 | 1500 |
| TSS 29 | 0.068 | 2000 |
| TSS 30 | 0.051 | 1500 |
| Mean Daily Intake+SD | 0.063+0.025 | |
| Mean Percentage Violation+SD | 1933.3+666.1 |
RESULTS
Table 1 depicts the sources of 30 tobacco snuff samples from the Nigerian geopolitical zones. Most south eastern and northern markets are the homes of medicated, tobacco snuff while the south west markets sell mainly the local variety.
Table 2 shows the level of the heavy metal nickel in each tobacco sample. Tobacco snuff samples (TSSs) 3 (north central Kuje) and 22 (northwest sabon-gari) contain the highest amount of heavy metal Nickel at 0.0011μmol/g. Lowest concentrations of 0.0003μmol/g are found in TSS 1,6,12 and 18. There was a statistically significant higher level of heavy metal nickel in 5 gm of each tobacco snuff sample, of the local tobacco snuff than in the foreign variety (z=2.11; p<0.05).
Table 3 shows the mean daily intake of the heavy metal nickel through consumption of TSS. The values are compared with FAO/WHO’s proposed maximum permissible level and percentage deviations from normal subsequently derived.
Fig. 2 shows the concentration of nickel per daily intake in ug/day for the different samples, placed side by side with recommended WHO concentration for comparative analytical purposes.
Fig. 3 depicts the levels of nickel in the Nigerian made tobacco snuffs in comparison with the foreign samples also placed side-by-side with WHO standard. There was a statistically significant higher level of heavy metal nickel in the Nigerian tobacco snuff than in the foreign smokeless variety (Z-score = 2.78, p<0.05).
DISCUSSION
The study showed the presence of the heavy metal nickel in all the thirty samples of tobacco snuff obtained from different commercial markets in Nigeria. Concentrations of nickel in the samples expressed in terms of their contamination level shows that the lowest concentration of 0.02 ug/kg which was seen in samples 1,6,12 and 18, while the highest concentration of 0.07ug/g was found in samples 3 and 22. This no doubt exceeds the recommended daily intake limits [8].
Due to the high percentage violation of nickel in all the samples, a vast majority of users of tobacco snuff are at risk of the various adverse health problems associated with it [9]. Nickel toxicity in tobacco snuff has been declared as carcinogenic to humans; by the International Agency for the Research on cancer (IARC) of the World Health Organization (WHO) [10]. Substances contaminated with nickel can cause skin allergies and cancer [11].
The high level of the heavy metal nickel observed in the tobacco snuff samples can be attributed to the fact that snuff is a smokeless tobacco substance in its crude form. The tobacco leaf is the primary recipient of this metal from contaminated soil, especially through the application of fertilizer by tobacco farmers.
Heavy metals have a special affinity for the leaves of the tobacco plant and the level of content of the heavy metal nickel in tobacco is directly related to the PH value (acidity/alkalinity) of the soil where it was planted. It could therefore be inferred from the result that the locally produced tobacco snuff are contaminated and dangerous to health. As a result, elderly Nigerian rural dwellers that often use the local snuff will be more susceptible to the tobacco related ailments than their city-dweller counterparts who use the imported variety.
CONCLUSION
The study revealed varying levels of nickel in the different samples of tobacco snuff widely consumed in Nigeria. The level exceeds the permissible doses as stipulated by the FAO/WHO. It also showed that Nigeria-made tobacco snuff contains higher levels of the heavy metal nickel than the imported variety.
Finally the results showed that tobacco snuff obtained from Kano, North West Nigeria contains the highest concentration of heavy nickel amongst all the studied samples.
Recommendation
The Federal Ministry of Health (FMOH) should put in place strict and implementable regulations as it concerns the production and use of tobacco snuff in Nigeria. Relevant regulating bodies such as Standards Organization of Nigeria (SON) and National Agency for Food Drug Administration and control (NAFDAC should test samples of the substance to determine suitability for human consumption.
Also health care workers should embark on awareness campaigns so as to enlighten their patients and the general public on the dangers inherent in the use of tobacco snuff.
ACKNOWLEDGEMENT
We are grateful to Miss Chinaza Vivian Onyejiaka for typing this manuscript and to Pharmacist Mrs. ZelinjoIgweze for supervising this work.
CONFLICT OF INTERESTS
Declared None
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