Bar is a village of about 1300 people, is a land locked village separated by Bununu river to the north and fenced by some hills both to the east and west. It had been known that once, some variety of minerals were exploited in the area but occur in quantities not viable for commercial purposes.
Over the past years, a health crisis of epic proportions had emerged in the Bar village, Bununu District, Tafawa Balewa Local Government Area of Bauchi State, Nigeria, as a result of the community changing from surface water to groundwater for drinking, cooking, and irrigation. The change from using surface water for drinking and cooking was initially hailed as a tremendous breakthrough for public health because of dramatic declines in mortality due to water-borne diseases caused by microbes. However, unknown to the installers of the wells who made this switch possible, groundwater in the village was contaminated with some toxic metals of hydro-geological origin. An outbreak of a strange disease characterized by migraine, fever, anaemia, hypertension, degenerative dementia and liver enlargement had killed dozens of people in this village. The disease, according to the villagers started in October 2003 and was attributed to the consumption of the hand-dug well water in the area. This incident was reported in Daily Trust newspaper of Wednesday May 31, 2006 and the once lively villagers have been living in fears as a result of these unknown diseases.
Subject to this, an epidemiology study carried out by the public health department of the Bauchi State Ministry of Health have also revealed that the said deaths were mainly drinkers of locally brewed alcoholic beverage produced in the area. The study was however rather suggestive because it is unable to show a clear link of the health effects of the concurrent exposure of toxic metals and alcohol administration.
Environmental pollution is said to be one of the major challenges in the modern human society today (Ali and Khan, 2018). Environmental contamination and pollution by heavy metals is a threat to the environment and is of serious concern (Hashem et al., 2017). Growth in industrialization and urbanization have caused contamination of the environment by heavy metals, and their rates of mobilization and transport in the environment have greatly accelerated since 1940s (Khan et al., 2004). Their natural sources in the environment include weathering of metal-containing rocks and volcanic eruptions, while industrial emissions, mining, smelting, and agricultural activities like application of pesticides and phosphate fertilizers are principal anthropogenic sources. Combustion of fossil fuels also contributes to the release of heavy metals such as cadmium (Cd) to the environment (Spiegel, 2002). Heavy metals are persistent in the environment, contaminate the food chains, and cause different health problems due to their toxicity. Chronic exposure to heavy metals in the environment is a major threat to living organisms (Wieczorek-Da˛browska et al., 2013).
Metal concentrations higher than the threshold levels affect the microbiological balance of soils and can reduce their fertility (Barbieri, 2016). Bioaccumulation of toxic heavy metals in biota of the riverine ecosystems may have adverse effects on animals and humans (Malik and Maurya, 2014). Higher levels of heavy metals in biota can have negative effects on the ecological health of aquatic animal species and may contribute to declines in their populations (Luo et al., 2014).
It should be emphasized that exposure to these toxic metals most often involves exposure to a combination of toxic metals rather to just a single metal; thus, accurate assessment of health risk due to drinking metal-contaminated groundwater must take into account potential interactions between the metals on the chemical, biochemical, and physiological levels. When subjects are exposed to metals in combination, the metals may each have their own typical health effects; they may also have synergistic or antagonistic effects on each other. In calculating cancer risks due to drinking water contaminants, it is vital to consider not only the health risks due to individual contaminants, but also those risks due to combinations of contaminants. Ingestion of metals in combination may increase or decrease the absorption of the individual metals in the digestive tract as well as also affecting the excretion of other metals (Ahmed and Ishiga, 2006; Dabak et al, 2018).
Absorption of metals through drinking water can be affected by certain diets. Interactions with dietary components and the general nutritional levels also affect the outcomes of exposure to toxic metals (Koboldt et al., 2012). Health effects due to co-exposures to toxic metals are further affected by behavioural and cultural practices (e.g. smoking, sun avoidance) and dietary habits (alcoholism). Particularly interesting are interactions between xenobiotics to which exposure is not often common. Examples of such substances are cadmium and ethanol. Interactions between cadmium and ethanol are an important problem in the field of modern toxicology, as both substances pose a risk to human and animal health (Omar, 2013).
Alcoholism is a serious problem in almost all countries. The excessive consumption of ethanol in the form of alcoholic beverages may be common among some industrial workers exposed to cadmium, including smokers (Omar, 2013). Ethanol is said to increases the permeability of biological membranes to cadmium (Brzoska et al., 2013) which can make alcoholics more susceptible to the effect.
Findings suggest that with typical patterns of exposure, multiple mechanisms probably contribute to the uptake of Cd in the proximal tubule in vivo (Prozialeck and Edwards 2012).
Regardless of the uptake mechanisms that are involved, it is clear that over time Cd can accumulate in the epithelial cells of the proximal tubule. The traditional view has been that when the tissue levels of Cd exceed a critical concentration of about 150 μg/g tissue, intracellular defenses such as MT and GSH are overwhelmed and the cells undergo injury and begin to die (Gobe and Crane 2010; Prozialeck and Edwards 2010).
Based on the above-mentioned studies, the dose, the duration, the chemical form of Cd in the kidney and intestinal tissue, and the exposure route of Cd must be considered as an important factor in evaluating the chronic effects of long-term Cd administration.
Liver and kidney are the important organs of metabolism, detoxification, storage and excretion of xenobiotics and their metabolites, and are especially vulnerable to damage. As the liver is an important target organ of ethanol (Thurman et al., 1999), and the kidney of Cd toxicity (Nordberg et al., 1994). Heart failure deaths, which make up 10% of all cardiovascular deaths, accounted for 30% of cardiovascular deaths related to metal toxicity (García-Niño and Pedraza-Chaverrí, 2014). Particulate matter exposures result in the delivery of metals to multiple extra-pulmonary sites where they form reactive centers that continually catalyze the generation of reactive oxygen species and induce oxidative stress.
This work is therefore designed to investigate the possible effects the concurrent administration of water containing cadmium and magnesium with graded concentrations of alcohol on the distribution, accumulation and retention of these metals on the liver, kidney and heart as well as the urine concentrations in order to establish the etiology of the cause of deaths mostly by alcoholics in Bar village.