Guest author: Aili Wang
Aili Wang is a PhD Candidate in Food Science and Technology working with Professor Susan Duncan. Her research focuses on the effects of water quality on metallic taste and its mechanisms, applying milk protein supplement on reducing metallic taste perception of cancer patients and healthy people and identifying taste interactions between commercial sweeteners and minerals ions in beverage products.
Although clean drinking water is essential for life, many consumers give little thought to how their water is treated before it reaches the kitchen tap. In the U.S., 286 million people, or about 85% of the population, receive their drinking water from a public distribution system year-round (EPA 2009). Though these rigorous standards insure that most drinking water is safe, many of these contaminants are regulated at the drinking water treatment plant (WTP), rather than at consumer taps (EPA 2009), and drinking water may have many miles to travel after it is treated. Even in the absence of harmful contamination, drinking water comes into contact with a variety of materials on its journey through the distribution system, which can result in significant aesthetic changes (Dietrich 2006).
Consumers play an important role in water monitoring since they are dispersed throughout the distribution system and they are the ones who use it every day. Consumers can detect changes in water quality when it first occurs by smelling, tasting and visually assessing the drinking water. In a study of human sensory thresholds of ferrous (Fe2+) iron in drinking water (Mirlohi et al. 2011), it was found that the overall population threshold was as low as 0.17 mg/L which was lower than the secondary drinking water regulations for iron (0.3 mg/L) (EPA 2012). It was also reported that copper can be detected by humans at very low concentrations ranging from 0.5-13 mg/L (Jesse et al. 1960; Cuppett et al. 2006), which is much lower than Secondary Maximum Contaminant Levels set by EPA for contaminants with organoleptic effects (Dietrich et al., 2015). Customer information on changes in water quality can help agencies to identify the problem cause and source, isolate the contaminated water, estimate the range of contamination and number of people who are impacted, take action to protect the unexposed population and estimate the amount of infrastructure that needs cleaning or replacement (Whelton et al. 2007).
In addition, consumers are the ones who suffer from problems brought on by decreasing quality of water. Exceeding chemical limits in drinking water can result in flavor changes and health concerns (Edwards et al. 2009; Dietrich et al. 2004, 2006). It was reported that sensory sensation of higher level of minerals such as iron and copper in drinking water were described as metallic, acidic, astringent, salty, or bitter by consumers (Zacarias et al. 2001). What’s more, excess chemical and biological contaminants in drinking water, such as lead, can be dangerous to human health. Lead presents a special situation. Lead is usually not present in drinking water when it leaves the water treatment plant. The primary sources of lead are from corrosion of lead solder and lead pipe present in people’s homes. Some homes have lead plumbing while others do not. In the case of lead contamination of drinking water in D.C. in 2003, two-thirds of the 6,118 residences tested had water that contained levels of lead above the action level of 15 parts per billion set by the EPA (Nakamura 2004). Among the households that tested for high levels of lead, two families and had water levels of lead as high as 435 and 310 ppb and they engaged a lawsuit on behalf of their young children. Elevated blood levels of lead were observed among children and pregnant woman in different districts (Edwards 2009, 2010).
Consumers can participate in water quality monitoring through actions such as making complaints, giving feedback and being trained as a volunteer. For consumers who are short of knowledge on water chemistry but sensitive in sensory perception, they can report abnormal drinking water characteristics to a certain agency and help the trained call taker to further clarify the problems. For the consumers who have basic knowledge on water or who frequently suffer water quality issues, they can take part in the survey of water utilities and give feedback on the water quality. In addition, consumers who are interested in improving water quality can join in a volunteer program and monitor the local water quality after appropriate training. Consumer participation can be a valuable way to improve the water quality and build a healthy living environment.
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