|Year : 2018 | Volume
| Issue : 1 | Page : 26-30
Lead in potable water sources in Anambra State, South East, Nigeria
Ignatius C Maduka1, Anthony I Anakwuo2, Nnamdi P Ogueche1
1 Department of Human Biochemistry, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria
2 Department of Medical Laboratory Science, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria
|Date of Web Publication||2-Jul-2018|
Ignatius C Maduka
Department of Human Biochemistry, Nnamdi Azikiwe University, Nnewi Campus, Awka, Anambra State
Source of Support: None, Conflict of Interest: None
Introduction: Due to lack of treated water supply in major cities and settlements in Anambra state, Nigeria, majority of the population obtain potable water directly from boreholes, streams, sachet, harvested rain, and well water sources. Lead-laden potable water may be a major cause of mortality and morbidity in Anambra state, Nigeria. Objective: This study was conducted to determine the presence of lead in potable water sources in Anambra state, Nigeria. Materials and Methods: Water samples were systematically collected from 81 water sampling sites in different senatorial zones of the state. Lead was estimated in the water samples using Varian AA240 atomic absorption spectrophotometer. Results: The mean levels of lead in the water samples in all the senatorial zones of the state were higher than the maximum contaminant limit (0.01 mg/L) set by the World Health Organization (WHO). The mean level of lead in harvested rain, sachet, and stream waters (0.34 ± 0.23, 0.37 ± 0.08, and 0.23 ± 0.06 mg/L, respectively) was higher in Anambra South senatorial zone compared to the WHO maximum contaminant limit. Furthermore, Anambra South has higher (P < 0.001) mean lead level compared to the North and Central senatorial zones. Conclusion: This study reveals significantly high lead levels in potable water sources in Anambra state, Nigeria. The water samples should be well treated to remove this harmful toxic heavy metal which is very dangerous to health.
Keywords: Anambra state, lead, Nigeria, potable water
|How to cite this article:|
Maduka IC, Anakwuo AI, Ogueche NP. Lead in potable water sources in Anambra State, South East, Nigeria. Afr J Med Health Sci 2018;17:26-30
|How to cite this URL:|
Maduka IC, Anakwuo AI, Ogueche NP. Lead in potable water sources in Anambra State, South East, Nigeria. Afr J Med Health Sci [serial online] 2018 [cited 2019 Mar 26];17:26-30. Available from: http://www.ajmhs.org/text.asp?2018/17/1/26/235734
| Introduction|| |
Water is one of the essentials that support all forms of plant and animal life. With the ever-increasing world's population, provision of good-quality drinking water is a challenge for government, especially in developing countries. It is generally obtained from two principal natural sources: surface water (fresh water, lakes, rivers, and streams) and groundwater (borehole water and well water)., Surface water is any water body which is found flowing or standing on the surface while groundwater is the water stored naturally beneath the earth surface. Water has unique chemical properties due to its polarity and hydrogen bonds, which enables it to dissolve, absorb, adsorb, or suspend many different compounds. Water is the basic constituent of all living beings; its effect on human body composition include thermoregulation, lubrication, solvent effect, catalytic function in biochemical reactions, hydration, digestion, nutrient transport, absorption of nutrients, and removing waste by urine.,,
In Nigeria today, one of the most important environmental issues is groundwater contamination. This contamination is due to infiltration of urban stormwater, leakage of wastewater, septic reservoirs, and improper industrial activities. Furthermore, the quality of groundwater is affected by the characteristics of the media through which the water passes, on its way to the zone of saturation. Groundwater is characterized by low temperature, low redox potential, high carbon dioxide, and mineral contents and is free from microbial contamination. Ojelabi et al. stated that boreholes are more susceptible to contamination. During infiltration of soil water, some pollutants are carried across the soil barriers into underground water sources, where they equally pollute the groundwater sources. It is also suspected that some groundwater sources such as wells and boreholes are likely to be polluted by leachates from pit latrines. The wastewater and the septic system effluent contain high concentration of dissolved organic carbon, ammonia, pathogen, organic micropollutants, as well as heavy metals, and trace elements. Heavy metals discharged by industries, traffic, municipal wastes, hazardous wastes, and accidental oil spillages from tankers result in a steady rise contamination of water bodies.
Lead is usually found in combination with other elements to form different minerals. This mineral is called galena and is most often mined to produce lead metal. Lead is a cumulative poison  and a possible human carcinogen. Long-term exposure to lead can affect most organs and systems in the body such as hematological system (inhibition of alpha-aminolevulinic acid dehydratase and haem synthetase) and nervous system (central nervous impairment and encephalopathy). Exposure to high lead level can damage the brain and kidneys and cause miscarriage in pregnant women. Furthermore, increased exposure to lead damages the organ responsible for sperm production.
There are so many sources of lead exposure including lead in paint, gasoline, water distribution systems, food, and lead used in hobby activities. Lead exposure attributed to automobile air emissions is a major exposure source. Lead poisoning is an environmental and public health hazard of global proportions. Children and adults in virtually every region of the world are being exposed to unsafe levels of lead in the environment. In fact, children are exposed to lead from different sources, such as paint, gasoline, and solder, and through different pathways such as air, food, water, dust, and soil. It can be from a single high-level exposure or the cumulative effect of repeated high- or low-level exposures. Once introduced into an environment, lead can remain in a dangerous form for a very long time. The primary source of lead in drinking water is from lead pipes, brass fittings, soldered joints, and dwellings connections used to distribute drinking water to consumers. The maximum contaminant level for lead in drinking water is 0.01 mg/L. The focus of this study is to determine the presence of lead in potable water sources in Anambra state, South East, Nigeria.
| Materials and Methods|| |
This study was carried out in three senatorial zones of Anambra state, Nigeria. Anambra state is a state in the Southeastern part of Nigeria, comprising of Anambra Central, Anambra South, and Anambra North as its senatorial zones. The state derives its name from Anambra River, formerly known as Omaballa River, the largest left bank tributary of the River Niger. It has its vegetation of tropical climate and experiences two air masses – equatorial maritime air masses associated with rain-bearing south-west winds from Atlantic ocean and dry dusty harmattan wind from Sahara desert. It has one of the highest population densities in Africa. This has posed other serious problems from undue pressure on the state's resources, fragile infrastructure, environmental sanitation, and social services. This pressure is especially evident in its huge commercial nerve center of Onitsha. It has an estimated population of over seven million with a land mass area of 4.844 km. The people of this area patronize water of questionable qualities due to failure of the State Water Corporation to provide potable water supply.
The study included 81 sampling sites: 9 streams, 9 sachet waters, 18 borehole water, 18 well water, and 27 harvested rainwater, all located within the various senatorial zones of the state. Harvested rainwater samples were collected from the roofing zinc sheets in each of the three senatorial zones of Anambra state, Nigeria. The inhabitants use the various water sources as drinking water, or for preparation of drinking water, and or for other domestic uses.
The sampling population was systematically stratified into the three senatorial zones with the same number of water sources selected per zone. The sampling technique involved a multistage technique: Stage 1 involved stratification into the three senatorial zones, while Stage 2 involved proportionate sampling of each of the sources of water (sites) accordingly: three streams per zone; three sachet water sites per zone; six boreholes per zone, and nine rainwater sites per zone. Stage 3 involved random sampling to select the actual site for sample collection.
Water samples were randomly collected from the various sites. Sampling was uniformly done between January and March 2015 in the morning hours (9 am–11 am) using standard techniques. Precautionary measures were taken following the standard guidelines of the World Health Organization (WHO, 2012) to avoid any possible contaminations. Water samples were collected by immersion of well-labeled sterile (5 ml) plastic universal container below the water surface for both streams and well water samples. Borehole water samples were collected directly from the tap (plastic), after running off the waste for about 2 min and sachet water samples were collected from their location of production. The samples in batches were taken to the laboratory immediately after collection and were analyzed within 7 days. Distilled water served as control.
The water samples were acidified with concentrated nitric acid; 1 ml of nitric acid was added to 5 ml of water sample and allowed to mix uniformly. This is to ensure the removal of organic impurities from the sample and prevent interference in heavy metal analysis.
The acidified water samples were analyzed for the presence of lead using Varian AA240 atomic absorption spectrophotometer. The calibration plot method was used for the analysis. Air acetylene was the flame used; hollow-cathode lamps of the corresponding elements were the resonance line source. The wavelength for determination of the element was 283.31 nm. The acidified samples were analyzed in duplicates with the average concentration of the metal present displayed in mg/L by the instrument after extrapolation from the standard curve.
The International Business Machine-Statistical Package for the Social Science (IBM-SPSS) Modeler 18.0 was used for the data analysis. Analysis of variance was used to test whether or not significant differences existed between groups. Pairwise comparisons were made using the post hoc test. Test probability value of P < 0.05 was considered statistically significant.
Compliance with ethical standards
This study was funded by the authors. There are no conflicts of interests. The research did not involve any human or animal participant. Ethical approval for this research was obtained from the Ethics Committee of the Faculty of Health Sciences and Technology of the Nnamdi Azikiwe University, Nnewi Campus, Anambra state, Nigeria.
| Results|| |
[Table 1] showed that mean levels of lead in all the water sources in Anambra state were higher than the WHO maximum contaminant limit (0.01). Borehole (0.05) water source showed least level of lead, while harvested rainwater contained highest level (0.14) of lead in Anambra state, Nigeria.
|Table 1: Mean±standard deviation (mg/L) lead in potable water sources in Anambra state|
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[Table 2] showed the mean (±standard deviation [SD]) levels (mg/L) of lead in various water sources among the senatorial zones of Anambra state. The result shows that the mean (±SD) level of lead (mg/L) in harvested rain was significantly higher in Anambra South (0.34 ± 0.23) compared with Anambra North (0.00 ± 0.00) and Anambra Central (0.10 ± 0.00) (P< 0.05), respectively. Similarly, the mean level of lead in sachet water was significantly higher in Anambra South (0.37 ± 0.08) compared with the means of Anambra North (0.00 ± 0.00) and Anambra Central (0.00 ± 0.00) (P< 0.05), respectively. The mean lead level (mg/L) in stream water was significantly higher in Anambra South (0.37 ± 0.08) compared with Anambra North (0.00 ± 0.00) and Anambra Central (0.02 ± 0.01) (P< 0.05), respectively.
|Table 2: Lead (mg/L) in potable water sources in senatorial zones of Anambra state, South East Nigeria|
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| Discussion|| |
From this study, the mean level of lead in all the water sources was higher than the WHO maximum contaminant limit of 0.01 mg/L. This finding is similar to the results posted by Adepoju-Bello et al. in Lagos, Nigeria, and Maduka et al. in Abakaliki, Nigeria. Lead levels are found to be higher in harvested rainwater followed by sachet water, which most people take regularly as “pure” water. This high level of lead in harvested rain and sachet waters is very alarming, considering the fact that these are the major sources of drinking water in the state. High level of lead in packaged sachet water could be as a result of contamination from the primary source, and possibly from the production site or from the storage material. Akudinobi and Okolo  reported that ionic species of hydrochemical significance recorded in industrial effluent wastes such as Hg 2+, As 2+, Cd 2+, Pb 2+, Zn 2+, Fe 2+, and NO 3– are continually being discharged (untreated) into the environment. This results in an elevated risk of pollution of water supply sources majorly through anthropogenic sources.
Mean level of lead was higher in harvested rain, sachet, and stream water in Anambra South senatorial zone. This may be as a result of the type of roofing material used, stream pollution, use of agricultural herbicides, pesticides and fungicides, industrial activities such as oil spillages, waste effluents, and use of lead blades in the refinery for stirring and metal deposits into streams. Water from these sources should not be used for domestic purposes as they are laden with lead which is dangerous to health as it may induce brain disorder and cause hypertension, kidney damage, anemia, and adverse reproductive outcomes. This present finding conforms to the result of the research work conducted by Igwilo et al. in Otuocha, Anambra state. This indicates that source-based treatment strategy should be adapted for effective decontamination. Conversely, the mean level of lead was lower in borehole water source. This may be possibly due to the very low depth of the waterbed. This indicates that this water source is better than the rest for domestic purposes in terms of lead contamination level.
| Conclusion|| |
The present study showed that there is a preponderance of lead in all the potable water sources in Anambra state, Nigeria. Furthermore, borehole water source contained lower level of lead, while harvested rainwater contained the highest level of lead. Anambra South senatorial zone contained the highest level of lead in stream, sachet water, and harvested rainwater, and these water sources may be dangerous to health.
Based on the findings from this study, we recommend that borehole water source should better be used for domestic purposes than other water sources studied. Source-based control measures should be applied while treating water for public consumption. Furthermore, effective legislation, enhanced public awareness campaign on water, and environment safety should be applied in this environment. Finally, government and drinking water production companies should take note of the need to treat water for public consumption properly to remove this dangerous heavy metal and other contaminants.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]