What arsenic exposure means to your health

The media has been awash with stories of arsenic and other heavy metal contamination in water, rice and other staple foods. Arsenic is a natural component of the earth’s crust and is widely distributed throughout the environment in the air, water and soil. 

Regulatory bodies such as World Health Organisation (WHO) and the American Food and Drug Authority (FDA), set acceptable levels or limits of arsenic in food or water, not exceeding 50 parts per billion (ppb) or 0.05 parts per million [ppm] or 50μg/l, to prevent toxicity in humans and animals.

However, in Uganda, according to an assessment of arsenic levels in rice brands sold in Kampala have arsenic levels ranging from an average of 1.4 parts per million (ppm) to 2.4 ppm. 

Although soaking the rice is said to reduce the contamination, the high levels of arsenic in tap water used in preparing  it increases retention of the metal on boiling, soaking and washing.

“We found higher arsenic amounts in water than the rice,” says Prof Robert Kalyesubula, the head of department physiology at Makerere University College of Health Sciences.

The silent threat

Most of the arsenic contamination in the environment is of geological origin from underlying rocks, but there is also a significant contribution from industrial pollution. Arsenic of industrial origin enters the environment in form of additives to pesticides (or insecticides), herbicides, cosmetics and herbal remedies, which end up polluting water bodies.

A research by the researchsquare.com reveals that the subsequent use of polluted water in irrigation of crops, then introduces arsenic into the food chain leading to potential intoxication of human beings and animals.

“Due to the fact that plants have the potential to absorb and accumulate arsenic from various soil types or environment, there is always a possibility of finding either some trace amounts or significant amounts of arsenic in the harvested and processed food stuffs,” reads part of the report.

Moreover, food crops such as rice have been reported to assimilate and accumulate 10 times as much arsenic as compared to other similar crops. It occurs in the safe but most commonly unsafe form. In the safe form, arsenic is required in very small amounts for the body to function properly.

Some people get arsenic exposure and toxicity by inhalation of arsenic fumes from industrial pollution or via direct skin contact with arsenic compounds. 

The unsafe form is usually a bi-product of chemicals used in industries. This product gets its way into the water through poor management of industrial wastes where they are damped in swamps and other water sources.

Foods such as yams, rice, sugar cane and others that are grown in swampy areas are likely to absorb this toxin. Other sources of arsenic exposure to humans include; contaminated water from the use of pesticides and herbicides, inhalation of arsenic dust from polluted air from car-fumes or industrial wastes and mining or smelting grounds.

According to the WHO, arsenic contamination of groundwater and food is a global public health issue and there are a number of regions where arsenic contamination of drinking-water is significant. A 2020 study estimated that up to 200 million people worldwide are exposed to arsenic-contaminated drinking water at levels above the legal limit of 10 parts per billion .

Arsenic is one of the major toxic metals in the environment that is also known to be carcinogenic with several other health side effects in human beings. 

Dangers of arsenic

Exposure to arsenic can cause both acute and chronic toxicity depending on the amount and duration of the exposure in the human body.

According to Prof Kalyesubula, large amounts of arsenic can cause acute problems with symptoms such as a fever, nausea, excessive salivation, vomiting, excessive watery diarrhea, rapid dehydration with consequent cardiovascular collapse, abdominal pain and in extreme amounts lead to organ failure.

Also, small doses of this metal can accumulate in periods between four to 10 years affecting all body organs and is said to be an increased risk of skin, lungs, kidney, nervous system, urinary bladder, spleen and intestinal cancers. 

“It can also affect the brain, causing peripheral neuropathy (weakness and numbness in the hands and legs), damage to the heart and the digestive system. In pregnant women, arsenic exposure can affect the development of the foetus, causing death of the unborn child or even the mother,” he says.

Lydia Aisu Pedun, a food scientist says the heavy metals such as lead, mercury and arsenic are very hazardous to your health because they are hard to expel. 

“The system is not able to flash out such heavy metals. The longer they linger in the body, the more they strain the kidneys. In the long run, the kidneys, which are responsible for filtering the toxins become damaged and the spill over is into the surrounding organs,” she says.

The way out

Boiling the water or food cannot reduce the amount of this toxic metal. However, Pedun advises individuals to take personal responsibility and grow their own vegetables at home to reduce the arsenic exposure.

She says, “I discourage people from growing foods in the wetlands especially in urban areas because many of them are contaminated. It is better to grow your own food at home limiting the use of pesticides.”

Pedun also advises industries to manage their wastes properly in order to limit industrial pollution and contaminating water with arsenic.

Prof Kalyesubula says it is necessary to routinely monitor for arsenic levels in the rice on the market and domestic water sources so as to protect the general public from arsenic toxicity. He advises people to eat food brands that have been approved by the Uganda National Bureau of Standards (UNBS). 

“If your water pipes are old, and probably have a leakage, this may expose the water to arsenic contamination. It is advisable that you change your piping or have the water filtered. The filtering process is however, expensive but the government needs to take action about the quality assurance on water safety,” says Prof Kalyesubula.