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What’s Lurking in Your Water?

Nov 23, 2018

Many of us wake up in the morning, open our taps for making coffee, showering and cooking without questioning the quality of tap water in our homes.  Excepting the occasional floating particles, you might think your tap water contaminant free for consumption. However, this is not always the case. Water’s intrinsic properties as a universal solvent, allows it to dissolve many chemicals and substances coming into contact.  As a result, clear water does not always equate to pure water!

While most utilities adhere to the regulatory levels, many of these standards are above levels scientifically known to pose risks. Moreover, with federal regulations have not been updated with emerging contaminants for the mere reason that studies quantifying risk and exposure across the population demographics (infants, adults, pregnant women, elderly) are not available yet.

Recent studies carried out by EWG (2010 -2015) in 50 states in the USA, reveal that out of 500 tested contaminants, 267 of them were present in the samples tested. Main conventional contaminants of concern were:

1. Chlorination By-products

In small doses, chlorination is carried out in order to kill parasites and bacteria in the water. However, long term exposure to chlorine by-products have shown to be causes of adverse effect to fetal development, birth defects and miscarriage (Nieuwenhuijsen et al,2000). Disinfection byproducts have also been associated with risks of bladder cancer development through ingestion as well as long term dermal exposure in a study carried out in Spain (Villanueva et al., 2007).

2. Bacteria

Inefficient treatment at water treatment facilities, human error is often the cause of waterborne bacteria (E.g. E-coli) contamination in drinking water.  In the USA alone, it is estimated that 560,000 people suffer from severe waterborne diseases, and 7.1 million suffer from a mild to moderate infections, resulting in estimated 12,000 deaths a year (Medema et al, 2003)

3. Lead

Flint, Michigan, recently made the headlines for lead contamination in their tap water through leaching from the corroded lead pipe into the water network. It is estimated that the lead contamination affected more than 100,000 people. Researchers from West Virginia University (Grossman & Slusky, 2017) have recently observed a decline in fertility rates in Flint communities. Fetal death rates increased by 58% following this crisis.

Sources of lead contamination are mainly as follows.

Lead Contamination in Water Systems

(Source:, 2018)

CNN (2016) estimates that approximately 5,300 water systems, serving 17.3 million people in the USA, have been reported violations to the lead and copper regulations (2015).

US lead statistics

(Source: EPA, 2017)

4. Hexavalent Chromium

Chromium is a naturally occurring element found in plants, rocks as well as animals. Whilst in its trivalent form, chromium is an essential dietary element (in trace amounts), hexavalent chromium has been widely reported to be toxic to humans as well as animals (Zhitkovich A., 2011).  As per current EPA guidelines (1986), hexavalent chromium is classified as highly carcinogenic from inhalation route of exposure. There are no current regulations quantifying risks via oral exposure.

Anthropogenic causes of hexavalent chromium contamination in groundwater are mostly due to industrial pollution from chemical, dyes, electroplating and tanning industry. One of the most serious cases of hexavalent chromium contamination in drinking water was highly publicized in the Erin Brockovich case, where cooling water containing high amounts of hexavalent chromium was discharged into unlined ponds and subsequently percolating into groundwater in Hinkley, CA.

You can check the level of chromium (6) in your area (US only) via the interactive map given by EWG by clicking here.

5. Arsenic

Arsenic is a heavy metal which occurs naturally in groundwater from natural rocks and deposits as well as from agricultural and industrial practices (smelting/mining/paints).  Arsenic exposure is well documented and known to be toxic after acute or chronic exposure.  Various studies point to arsenic related health issues such as coronary heart disease, bladder cancer, lung cancer, skin lesions, reduced child cognitive function, as well as childhood cancer (Smith & Steinmaus, 2009).

Researchers estimate that above 2 million people in the USA are drinking arsenic contaminated water.

Arsenic Contamination in USA

(Source: U.S Geological Survey, 2017)

 6. Perfluorinated Chemicals (PFCs)

Perfluorinated chemicals find their way into our water sources mostly from industrial sources. They are also not degradable in the environment and will be undefinitely lingering in our ecosystem. The quest for slippery/non-stick materials (e.g.Teflon for kitchenware  / scotchguard) has increased an unprecedented amount of perfluorinated chemicals during the past decade. It is only now that people are able to link the chronic adverse effects such as high cholesterol, thyroid disease, testicular cancer to the chemical. The following map from EWG shows the extent of PFCs (measured as PFOA) tap water contamination in the USA as of 2018.

PFAS water contamination in USA

(Source: EWG, 2018)

7. Uranium

Uranium is a radioactive element which finds its way to our environment through mining/nuclear practices. Without proper disposal, uranium may contaminate groundwater and cause significant health adverse risks such as renal failure and bone cancer.  Research carried out in 2015 by Nolan & Weber has found that nitrates contamination from agricultural practices help solubilizing uranium and hereby increasing its mobility in our environment. The level of uranium groundwater contamination was highest in CA by 189 times the EPA threshold.  The following graphic shows the concentration of uranium and nitrate found in various areas across the USA.

Uranium and Nitrate Water Contamination in USA

(Source: Nolan & Weber, 2015)

 8. Radium

Radium is the most common radioactive element and known carcinogen which naturally occurs in soil as a result of uranium and thorium decay and contaminates groundwater. In a report released by EWG, it is estimated that more than 170 million Americans are drinking water contaminated with radium with highest incidence in Texas (80% of the population).  This seems to correlate with a study carried in Harris County, Texas (Cech et al., 2007) has been linked exposure to radium through ingestion to an increase in orofacial cleft birth defects prevalence, wherever significant amounts of radium were found in drinking water! Moreover, fracking is known to significantly add to the contamination problem.

You can check the level of radium in your area (US only) via the interactive map given by EWG by clicking here

9. Microplastics

Plastics have infiltrated each and every aspect of our lives! Since its industrial production dating to 1950s, we have produced 9.2 billion tons of plastic, out of which 6.9 billion is plastic waste which we need to deal with! Microplastics have been found in oceans, all around the globe. But this is not restricted just to our oceans.  An ugly legacy and a big price to pay for convenience! The health effects of microplastics have not been thoroughly documented. However, researchers are concerned about the risks of microplastics being lodged in human intestines.  A study carried out by Orb Media sampled tap water across a dozen countries and found that 83% of the samples to be contaminated worldwide.

People having doubts about the quality of their tap water might be tempted to drink bottled water. Think again! Bottled water is not as pure as perceived! We are directly ingesting microplastics every time we choose to drink bottled water! A study carried out by Fredonia, State University of New York has also found out that of 239 samples of reputed bottled water producers around the world, a staggering 93% of them contain microplastics having size greater than 100 microns (Mason et al.; Orb Media). Recently, a bill was signed in California, making it the first state in the US to mandate microplastics testing by drinking water suppliers by 2021.

Microplastics Water Contaminations Around The World

(Source: Statista)

 10. Pharmaceuticals & Personal Care Products (PPCP)

PPCP compounds have found their way to drinking water through recycling of sewage / municipal /agricultural /aquaculture wastewater. The reasons for it are excretion of impartially metabolized chemicals in humans/livestock/fish and improper disposal surplus pharmaceutical products of which end up in the wastewater. Abnormalities (intersex fish, balance shifting of bacteria/algae) in aquatic creatures (intersex fish, behavioural modification, balance shifting between species) have been observed wherever PPCPs have been found. Inspite of most sewage / domestic wastewater treatment facilities remove big number of contaminants, they are not designed to remove pharmaceuticals.  We currently have no gauge of how these compounds bioaccumulate up the food ladder and adversely affect us. There are currently no regulations mandated by the EPA for measuring PPCPs in surface / drinking water for human consumption.


References :

  1. Nieuwenhuijsen MJ, Toledano MB, Eaton NE, et al; Chlorination disinfection byproducts in water and their association with adverse reproductive outcomes: a review; Occupational and Environmental Medicine 2000;57:73-85.
  2. Medema GJ, Payment P, Dufour A, Robertson W, Waite M, Hunter P, Kirby R, Anderson Y. Assessing Microbial Safety of Drinking Water Improving Approaches and Method.WHO & OECD, IWA Publishing; London, UK: 2003. Safe drinking water: an ongoing challenge; pp. 11–45. 
  3. Grossman D & Slusky D. The Effect of an Increase in Lead in the Water System on Fertility and Birth Outcomes: The Case of Flint, Michigan. Working Paper Series, Department of Economics, West Virginia University; pp. 17 – 25. 
  4. Environmental Protection Agency,2018.; Basic Information about Lead in Drinking Water
  5. CNN, 2016.; 5,300 U.S. water systems are in violation of lead rules 
  6. Villanueva CM et al., 2007;  Bladder Cancer And Exposure To Water Disinfection By-Products Through Ingestion, Bathing, Showering, And Swimming In Pools; Am J Epidemiol. 2007 Jan 15;165(2):148-56. Epub 2006 Nov 1.
  7. Zhitokovich Anatoly, 2011; Chromium in Drinking Water: Sources, Metabolism, and Cancer Risks; Chem Res Toxicol. 2011 Oct 17; 24(10): 1617–1629 
  8. Smith, A. H., & Steinmaus, C. M. (2009). Health effects of arsenic and chromium in drinking water: recent human findings. Annual review of public health, 30, 107-22. 
  9. US. Geological Survey, 2017. Study Estimates about 2.1 Million People using Wells High in Arsenic  
  10. EWG, 2018; Known Contamination from Toxic Fluorinated Chemicals Keeps Spreading, With No End in Sight.  
  12. Nolan & Weber.; Natural Uranium Contamination in Major U.S. Aquifers Linked to Nitrate; Environ. Sci. Technol. Lett., 2015, 2 (8), pp 215–220
  13. Cech et al., 2007;  Spatial distribution of orofacial cleft defect births in Harris County, Texas, 1990 to 1994, and historical evidence for the presence of low-level radioactivity in tap water; South Med J. 2007 Jun;100(6):560-9
  14. McCarthy, 2018.; Study Finds Microplastics In 93% Of Bottled Water
  15. Mason et al., Orb Media; Synthetic Polymer Contamination In Bottled Water; State University of New York at Fredonia, Department of Geology & Environmental Sciences.