The acidification of oceans, lakes, and streams causes detrimental effects on these delicate ecosystems [12] [14]. Since humans are a part of these ecosystems and we rely on water, plant, and animal foods for survival, changes to these ecosystems invariably affect us [3]. Acid rain also affects us more directly in the form of air pollution and toxic metals exposure.

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Air Pollution

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SO2 and NOx form fine sulphate and nitrate air particles that irritate the respiratory tract when inhaled. These air particles can contribute to life-threatening lung and heart conditions, and cancer [3] [14]. For more information, please visit our global environment section about air pollution, and health effects sections about cardiovascular disease and cancer.

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​Mobilization of Toxic Metals

Acid rain decreases the pH of soil and water, which strips the soil of essential minerals and mobilizes toxic metals from contaminated soils. Mobilized toxic metals are more likely to contaminate groundwater or be absorbed by crops planted on or near polluted soils [3] [10]. Of these toxic metals, human exposure to lead, cadmium, mercury, aluminium and arsenic are of particular concern.

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Lead

Drinking water acidification leads to increased lead mobilization from lead-containing pipes and plumbing systems [3]. Lead exposure poses a significant risk to human health, with children particularly vulnerable [17].

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Cadmium

Cadmium poses significant health risks even at low levels of exposure. According to a review by Genchi et al., cadmium exposure can lead to kidney and liver damage, cardiovascular effects, increased risk of cancer and osteoporosis, immune suppression, and adverse reproductive and developmental effects [2]. The health effects of cadmium are outlined in more detail, here. 

 

Mercury

Acidic water converts inorganic mercury to methylmercury - the more active and toxic form of mercury - leading to a rise in methylmercury concentrations in the fish we eat [3]. Methylmercury is a potent neurotoxin that poses significant health risks to humans [6]. Epidemiological studies have shown developmental impacts of exposure leading to loss of IQ and a decrease in language, memory, and attention span [6].

 

Aluminium

Aluminium is an abundant element in the earth’s crust [8] and is found in high concentrations in sedimentary rocks [4]. Acid rain mobilizes aluminium from the rocks, leaching it into the soil and surrounding waterways. Because of aluminium’s abundance, it is the most and  detrimental to watershed ecosystems and fish mortality [1]. In humans, ongoing research explores the neurological impacts of aluminium exposure and its correlation to Alzheimer’s disease [8].

 

Arsenic

Arsenic is another toxic element that can cause severe health effects in humans following elevated or prolonged exposures [16]. Arsenic is classified as a carcinogen by the International Agency for Research on Cancer and long-term exposure is linked to an increased risk of various cancers, including skin, lung and bladder [16]. Long-term arsenic exposure is also linked to diabetes, cardiovascular disease, and poor cognitive development [16].