The use of metals has been critical to the progress of human civilization and this has resulted in their ubiquity despite their suspected toxicity 1. Human exposure has risen dramatically as a result of an exponential increase of their use in several industrial, agricultural, domestic and technological applications 2. Some metals however are essential in biological processes while others have unknown biological functions; either favorable or toxic 3. It had been found that the non-essential toxicant metalsmimic essential ones thereby gaining access into the body and potentially disrupting key cellular enzymes resulting into a wide range of health conditions 4. Among these metals, Aluminum is the most widely distributed being a trivalent cation found in its ionic form in most kinds of animal tissues and natural water 5.Human are continually exposed to this metal via cooking utensils, food products, drinking water and medicines 6

A report of its detrimental effect on reproductive organ 1, the kidney 7, the brain 8 and liver 9 has been documented. Since aluminum sulphate is being used in urban water treatment despite its presence in natural water, food and vegetables, this might expose the populace to a higher concentration of aluminum. Epidemiological studies have indicated a link between aluminum in drinking water and Alzhiemer’s disease and a variety of human and animal studies have implicated learning and memory deficits after aluminum exposure. 1011. Evidences of its accumulation in various organs have been documented; brain, bone, liver and kidney 1213 and is accompanied by renal failure or associated with age 14. Aluminum has also been reported to displace essential metals from their position thereby altering normal cellular processes 15. Despite evidences linking the exposure to aluminum with endocrine disruption 16, and unsatisfactory result from water treatment (inability to reduce the turbidity of water), yet many countries still employs the use of aluminum sulphate in its water treatment. Considering the inadequacy for toxicological data in this area, this experiment was conducted to explore the risk factor by testing aluminum sulphate in the adrenal gland of an adult Wistar rat for possible alterations in structure.

Thirty male adult Wistar rats weighing between 120 - 150g were procured from a breeding house and were used for this experiment. They were obtained and housed in standard cages under standard conditions. They were fed with feed pellets (grower mash). The rats were acclimatized for two weeks before commencement of drug administration. The Wister rats were divided into three groups each contained 10 animals; group A was the control group received no addition with drinking water, group B animals received 10g of alum dissolved in 1000cm3 of distilled water and were tagged T1, group C animals received 50g of alum dissolved in 1000cm3 of distilled water and were tagged T2 via drinking water for four weeks.

There was a decrease in the mean weight of rats in the treated groups when compared to the control group even at the initial stages of administration, also there was a significant decrease (p < 0.05) in the mean weight of rats in the treated groups at the final stages of the administration (Table 1).

Analysis of body mass provides important information on the general toxicity of a compound and its implications on health 6. According to existing literature, there seems to be apparently conclusive evidence that aluminum intoxication is associated with a decrease in the body weight of exposed subjects. The significant decrease in body weight associated with aluminum administration that was recorded is similar with the findings of Johri et al., 1718. Physically, the rats were observed to manifest signs of weakness during the period of administration. This lethargy was observed to be accompanied by loss of appetite, as a large amount of the feed were untouched during this period. The significant decrease in the body weight that was observed during this period may be attributed to a decline in food consumption since weight change depends on a balance between energy expenditure and food consumption.

The main mechanism of aluminium toxicity involves the disruption of the homeostasis of metals, such as magnesium (Mg), calcium (Ca), and iron (Fe) 15. The physical and chemical properties of aluminium allow it to effectively mimic these metals in their respective biological functions and trigger biochemical abnormalities. Aluminium has been shown to replace magnesium and bind to phosphate groups present in cell membrane, DNA and ATP 19. However, the effect of aluminium on iron homeostasis is the pivotal factor that renders this metal toxic 2021. This interaction generates labile iron from iron-containing enzymes and proteins. The intracellular pool of free iron therefore increases; a situation conducive to the formation of reactive oxygen species. Indeed, elevated levels of reactive oxygen species have been documented in various systems exposed to aluminium 222324. In the present study, the histology of the adrenal gland of the control group (plate 1-6) shows apparently healthy histoarchitecture with well define-cellular layers and boundaries. Cells at each layer are well defined and identifiable. Whereas, observed in the treated groups were obliterated cells, haemorrhagic necrosis and enlarged central vein. A disruption in cellular integrity is a pointer to a disturbed functionality. Since the adrenal gland plays a vital role in the production of hormones that regulates the storage of end products of metabolism and also secretes dopamine (adrenal medulla), therefore, the aforementioned process might have been impaired. To the best of our knowledge, little or no literature exists on the effect of aluminum sulphate on the adrenal gland.

Aluminum sulphate has a detrimental effect on the body weight and structure and by extension, on function of the adrenal gland. Therefore, its use in the treatment of water and other industrial application should be done with caution. We recommend further studies to elucidate the mechanism via which aluminum causes its toxicity and the dosage of aluminum that would be considered safe.