Mapping the health and environmental impact of aluminum is important, given that more than 130 tons of bauxite is extracted each year globally, highlighting the extent of our shared dependence on the metal. While efforts have been on to maximize the energy-efficiency of aluminum, its environmental and health impact is still considerable at many levels. It must be pointed out that the transformation of bauxite to aluminum at the industrial level is dependent on astronomical quantities of electricity, water and energy. Furthermore, the inherent stability of aluminum ore only increases its resistance to easy extraction. During aluminum smelting, perfluorocarbons released are approximately 9000 times more detrimental to the surrounding environment than carbon dioxide, so far as global warming is concerned. Besides, strip-mining of bauxite encourages considerable loss of habitat and food in the mining regions. Both smelting and processing of aluminum release a significant amount of greenhouse gases such as carbon dioxide, sodium fluoride, sulfur dioxide, perfluorocarbons, and so on.
Most Al-toxification is caused by acid rain, although industrial release of aluminum into water-bodies has been a significant contributor to pollution. Experiments have highlighted how aquatic species are affected by increased levels of aluminum in freshwaters impacted by acid rain and industrial sources. pH and Al tamper with the physiology of invertebrates and fish. Aluminum attacks the gill, which results in simultaneous ionoregulatory, osmoregulatory and respiratory dysfunction which, in turn, damages the cells, leading to the death of the fish. Likewise, a number of species, including zebrafish, minnow, rotifers and snails are highly vulnerable to aluminum toxicity. Accordingly, several criteria models have been recommended to regulate the concentration of Al in water-bodies.
The impact of aluminum on plant life has been experimentally proven. Indeed, over the last four decades, the potential role of aluminum ions in the dwindling of forest areas in (predominantly central) Europe has been plausibly validated. Al3+ ions have been known to engender physiological distortions such as reduced membrane potential in the root, increased non-electrolyte permeability, decreased water permeability, inhibited DNA synthesis etc. – some of the well-documented effects of aluminum on plant life. At the same time, it is important to recognize that the response to aluminum differs from one species to the next. For example, Scots pine is more Al-tolerant than white birch which, in turn, outstrips the AI-tolerance of Norway spruce. Very broadly speaking, plants growing on acidic soils tend to be more impervious to Al-toxicity.
While aluminum has been found to affect terrestrial wildlife in more ways than one, the extent of the impact of AI is yet to become apparent. Perhaps the most well-known study is the one carried out by Nyholm in 1981 who shed light on the effects of aluminum on wild passerines. The birds showed breeding defects, such as eggshell deterioration, compromised clutch size and high mortality rates. The study carried out by Nyholm found how aluminum was responsible in triggering osteomalecia in the species. The birds, having fed on insects from acidic lakes with significant Al-concentration, began showing the aforementioned symptoms. Humans, too, respond likewise to the accumulation of aluminum in the bones. Several kinds of blood diseases have been found in terrestrial animals. For instance, the level of Al in the blood of cows with lymphoreticulosis was two times higher than that in healthy cows. Similarly, upon testing the serum of sick cows, it was found to contain thrice the amount of aluminum in the serum of healthy cows.
The impact of aluminum on humans has been vividly studied. The concentration of aluminum in lung tissue, hair, genitals, kidneys, bones, liver, larynx etc. has been well-documented. The skin of the human embryo has been found to contain the highest concentration of aluminum. Patients with pancreatic ailments such as chronic pancreatitis and cholangioheptatitis showed higher-than-usual levels of aluminum. High concentration of aluminum has been traced in human fingernails too. So far as human milk is concerned, individuals with hypogalactosis had high levels of aluminum in their milk. The impact of low free-oxygen environment has been mapped towards confirming considerable aluminum content in human hair. Individuals affected by tuberculoma and lipid nephrosis showed increased Al concentration in the kidneys. Lately, significant Al content was traced in the brain tissue of Alzheimer’s-affected patients.
Studies have been carried out to understand the effects of aluminum in human food. Food additives containing aluminum are widely used in a slew of bakery products such as waffles, muffins, coconut tarts, steamed buns, and cakes. Salted jellyfish has been found to contain high Al concentration, thanks primarily to the use of alum as the firming agent. Fried snacks have also been found to contain high Al levels in the food additives. Today, the average dietary exposure to aluminum in adults is approximately 60% of PTWI (provisional tolerable daily intake), which is evidently considerable at all levels. What complicates the situation is that individual consumption patterns are hardly mapped. Which implies that high-consuming individuals are thrice as exposed to dietary aluminum than average consumers. Specifically, individuals heavily dependent on the aforementioned bakery products are highly vulnerable. The concentration of aluminum in human diet depends on a number of factors. It is important to recognize that aluminum may be naturally found in foods; however, increased exposure to aluminum primarily comes from the use of Al-high food additives. The use of aluminum-made cooking implements is no less a contributor. Drinking water contains aluminum in the form of flocculent or coagulant. The highest levels of aluminum in drinking water were found in Germany with an average concentration of 2 mg/L. Similarly, high Al content has been found in non-alcoholic drinks such as fruit juice. Moreover, beverages packed in aluminum cans report high Al-content anyway. So far as alcoholic drinks are concerned, wine contains the highest amount of aluminum. Due to the high acidity of the soil where grapes are grown, both Spanish and German wines have recorded high Al-content. Tea plants are widely known for being acidophilic. As a result, tea is naturally a carrier of high Al-content. According to relevant studies, tea accounts for 50% of the daily Al-intake, especially in countries where tea is the staple beverage. Fruits and vegetables too have been known to contain significant amounts of aluminum. Again, the degree of Al-exposure depends on such factors as plant variety, soil conditions, the water used for irrigation, and so on. Al-content varies from one plant species to another. Accordingly, the highest levels of aluminum were found in squashes, cabbages, marrow, watercress and spinach. Baked potatoes were also found to contain aluminum. The lowest amount of Al has so far been found in green beans (cooked). Bananas (from Spain) were found to contain the highest concentration of aluminum. Animal products have been traced with considerable AI-content. For instance, the highest level of aluminum in fresh meat was found in viscera (11.2 mg/kg), whereas the lowest level was found in pig meat (0.21mg/kg). The popular hamburger from the USA contained the highest level of aluminum (20mg/kg), thanks to the extensive use of aluminum additives. Similarly, the use of emulsifying agents such as sodium aluminum phosphate in processed cheese contributed to the highest amount of aluminum in milk (470mg/kg). Seafood has been shown to carry significant levels of aluminum. Consider, for example, sea squirts from South Korea with an average Al content of 204.6 mg/kg. Similarly, Al concentration in edible seaweed is considerably higher than in fish – approximately 52.1 mg/kg in the former.
The presence of aluminum in human diet continues to challenge outworn models of food safety across the globe. While naturally-occurring aluminum in human food is fairly sustainable, the ever-rising dependence on aluminum additives can be regulated. It is fair to say that aluminum has seeped intractably into our food chain; still, more robust monitoring can make a big difference.
Human exposure to aluminum, directly or otherwise, extends far beyond dietary practices. Exposure to aluminum foil, cooking utensils and cosmetic products is equally harmful. In cosmetics, deodorants contain aluminum salts which are added to increase the anti-perspirant tendency of the product. Similarly, daily, unregulated exposure to aluminum in the form of cooking and baking utensils has outstripped the rate of exposure through food. Consequently, non-dietary products are the biggest source of aluminum contamination today.
Recent research has identified dermal exposure (in the form of anti-perspirants) to aluminum as the biggest source of Al contamination. However, the good news is that it is not beyond us to monitor the extent of Al-exposure. For instance, customers should check the presence of aluminum salts in cosmetic products. If present, such products may be used moderately. Toothpastes have been found to contain aluminum. The best possible way to minimize Al-intake is to change brands from time and time. Sticking to a varied diet should be prioritized. Where possible, storing acidic and salty food products in aluminum cans should be avoided. Newborns are particularly vulnerable to aluminum. Therefore, for the first six months, the baby should only be breastfed. Likewise, older people, especially those with Alzheimer’s and Parkinson’s, are at high risk of aluminum contamination. Aluminum has long been considered a risk factor in neurological disorders, especially in the form of Al-containing medicines, although aluminum is not considered to be a neurotoxin. Increased amyloid aggregation and deposition in Alzheimer’s has been traced to increased Al-exposure. Ingesting antacids on a daily basis has contributed to enhanced Al-levels in patients with gastric ulcer. The starting steps to monitor Al-intake is to map the daily dose-exposure and the effects of responding to the dose. Since the extent of daily Al-intake is difficult to measure, mapping can identify the variables that need to be controlled at the earliest. Exposure to aluminum can also be controlled by using Al-containing medicines, such as buffered aspirin, only as directed.
The sum of Al atoms present inside or on the human body at a given time is referred to as the body burden. Estimating the body burden of aluminum is the first step towards minimizing exposure. Drinking silicon-rich water is useful for gauging and minimizing the body burden of Al with ageing. The use of anti-perspirants may be done away with to encourage Al-excretion through sweat. Occupational exposure to aluminum is equally disastrous. Aluminum powder should be immediately transferred from drums to process containers. Aluminum powder should always be stored in a cool place and away from direct sunlight. While handling containers of aluminum powder, workers should count on tools that do not give off sparks. Where possible, aluminum should preferably be inerted by nitrogen. Workers handling aluminum on a daily basis should use protective clothing, such as gloves, suits, footwear, headgear, side shields or goggles, face shields etc. Where Al-exposure through skin is possible, emergency showers should be readily available. In hospitals, inappropriate use of respirators can prove fatal in terms of Al-exposure. If the patient can smell, taste or detect aluminum while wearing a filter or cartridge respirator, he or she should leave the vicinity immediately. The seal linking the respirator to the face should be in proper condition. If not, a new respirator may be needed. Otherwise, replacing the cartridge or the filter will do. Evaluating the efficiency of a respirator is important. The National Institute for Occupational Safety and Health has classified filters and respirators into N, R, and P series. The filtering efficiency of each is 95%, 99% and 99.9% respectively. Accordingly, the efficiency of the respirator should be checked with the supplier before active use.
The modern age is dependent on aluminum in more ways than one. Industrially and otherwise, human beings are continuously, often unwittingly, exposed to aluminum in various ways. The large-scale exposure to aluminum may tempt one to explore the possibility of a blanket-ban on the metal! However, it would be a far-fetched idea. Given the huge stakes involved, the best we can do is keep tabs on aluminum intake and strive to regulate it as efficiently as possible. Both the government and the public are equally responsible for modulating Al-exposure. While strict federal laws are needed to be enforced dynamically, people should be keen enough to participate in the struggle to scale down the impact of Al-intake, especially for the sake of the ultra-vulnerable such as newborns and older people. So far as occupational exposure is concerned, employers must recognize that safety is the fundamental right of workers. Therefore, where personal protective equipment is not available or is inadequate, it can lead to serious charges of exploitation of workers.
Mapping and developing a safety spectrum when it comes to Al-exposure is still a far-cry, unlike in the case of other metals whose safety credentials are known and whose use, daily intake etc. are closely monitored by appropriate medical, occupational and federal guidelines. The health impact of aluminum continues to be largely elusive, which only complicates the global challenge further. Therefore, until appropriate standards have been satisfactorily established, it is in the best interests of all to take precautionary measures where needed.
Published On: Nov 01,2020 20:20
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