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Water Treatment Techniques Linked to Generation of Harmful Toxins

filling a glass with water from the faucet/ Photo By BOKEH STOCK via Shutterstock

 

Public water quality has been a cause of concern due to disturbing discoveries of lead levels in US-based city waters. This is based on research conducted by Elise Deshomme and Michele Prevost. One would think that once the chemicals in water are removed during the water treatment process then the job is done and the water is safe for human consumption. 

However, according to Carsten Prasse, an assistant professor at the Johns Hopkins University, Department of Environmental Health and Engineering, the removal of the chemicals in water could lead to the conversion of the chemicals into products that may be harmful and toxic to the human body.

To get rid of toxic chemicals in water, treatment plants often use oxidation methods such as the use of hydrogen peroxide and UV light to turn the chemicals into presumably less harmful compounds known as transformation products.

Past studies have focused on the by-products of water purification processes such as chlorination, which has now been replaced with newer processes such as oxidation. Unfortunately, not much is known about the products formed during some of these newer processes. The transformation products formed post-purification are typically considered to be less toxic but a team of scientists from the University of California, Berkley, clarifies that this may not always be the case.

The study looks at phenols, a class of anthropogenic and natural chemicals that are common in the water supply. These phenols are present in almost everything from dyes, personal care products such as skin care and cosmetic products to pharmaceuticals and pesticides including bisphenol A, triclosan, and nonylphenol-ethoxylates. Phenols are also naturally occurring chemicals in water.

 

water droplet from a faucet/ Photo By Carlos Marques via Shutterstock

 

The team used peroxide radicals to determine what compound the phenols transform into. This process is commonly used in water treatment plants. Amino acids and proteins were then added to the mix, a clever biomedicine technique. Using backward calculations, the team then went ahead to determine what compounds the phenols must have turned into in the earlier step.

The result was the conversion of the phenols into a variety of compounds including unsaturated dialdehyde 2-butene-1, 4-dial. This compound is known to have adverse effects including DNA damage on human cells as it induces strand breaks and cross-links in DNA. Interestingly, furan, a toxin in cigarette smoke and car exhaust, is also converted to unsaturated dialdehyde 2-butene-1, 4-dial in the body and this conversion could be the reason for its harmfulness and toxicity.

The team further went on to test the extent of the effect of 2-butene-1, 4-dial on biological processes by exposing the compound on mouse liver proteins. The results revealed that the compound affected 37 different protein targets involved in a range of biological processes including protein synthesis, energy metabolism, and steroid synthesis. One enzyme that the 2-butene-1, 4-dial proved to inhibit is paramount in apoptosis, also known as cell suicide. Inhibiting this enzyme in living organisms may lead to unchecked cell proliferation or cancer growth.

Unsaturated dialdehyde 2-butene-1, 4-dial also interferes with compounds that play a key role in metabolism, therefore, leading to potential health outcomes such as obesity and diabetes. “There is a known connection between pesticide exposure and obesity and this research may help to further explain why this is,” says Prasse. By this, Prasse means that since pesticides contain phenols that transform into 2-butene-1, 4-dial, then pesticide exposure interferes with metabolism and therefore leads to obesity.

The results of this study are exciting since this is the first time that such methods have been used in water treatment. The team, therefore, hopes that the methods will be expanded to screen for other types of compounds. The next step is to find out how this method can be used on more complex samples to study other contaminants likely to result in the formation of similarly reactive transformation products.

Water purification can be difficult since contaminants come from a variety of sources. For instance bacteria, plants, agriculture, and wastewater-household products that we use contain nearly 80,000 different chemicals that end up in wastewater. It is not always clear what chemicals are in the water and what transformation products they generate during the water treatment process. Approaches are, therefore, needed to prioritize the investigation of compounds that are toxic or that might be converted into toxic transformation products during water treatment.

By 2050, two-thirds of the world’s population will reside in areas that depend on drinking water that contains run-off from farms and wastewater from cities and factories. This is according to a research conducted by the United Nations, Department of Economic and Social Affairs, Population Division back in 2015. Therefore, safe and effective water purification techniques will be even more critical in coming years. Studies like Prasse’s will be important in ensuring that the water we drink is truly safe for human consumption.

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