Arsenic is a naturally occurring mineral that is found in the drinking water of all 50 states. Contamination can come from natural, industrial or agricultural sources.

The EPA and World Health Organization classified arsenic as a “known human carcinogen.” It presents serious health risks, including:

• Bladder cancer
• Lung cancer
• Skin cancer
• Liver cancer
• Kidney cancer
• Prostate cancer
• Kidney damage
• Cardiovascular disease

The EPA currently sets a legal level of arsenic in drinking water at 10 ppb (parts-per-billion). However, the EWG believes that is limit too high. Their guideline sets acceptable levels at 0.004 ppb. In the report released by the EWG, Lake in the Hills had levels of arsenic at 0.288 ppb, or 72x higher than the EWG guideline.

The haloacetic acids are a group of five acids, including monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid and dibromoacetic acid.

These acids form when disinfectants, like chlorine, are added to drinking water. The health problems associated with consuming these acids include a higher risk of cancer and problems to fetal growth during pregnancy.

The EPA sets a limit for all haloacetic acids to be at 60 ppb. However, the EWG sets their acceptable standard at 0.1 ppb. A recent test showed the levels at 16 ppb, or 160x the EWG limit.

Three of the haloacetic acids also exceeded the EWG limits:

• Dibromoacetic Acid – 0.593 ppb (15x higher than the EWG standard)
• Dichloroacetic Acid – 6.17 ppb (31x higher than the EWG guideline)
• Trichloroacetic Acid – 9.23 ppb (92x higher than the EWG health guideline)

Radium is a radioactive element that infiltrates water from natural sources as well as oil and gas extraction activities. If there is enough radium in the water, it can lead to bone cancer, kidney damage, congenital defects.

Both the EPA and the EWG test for two types of radium, radium-226 and radium-228, and combine the results in their reports. The EPA sets the legal limit for radium at 5 picocuries per liter (pCi/L), while the EWG sets a lower limit of 0.05 pCi/L.

As of 2017, the levels of radium-226 and radium-228 in Lake in the Hills’ water tested at 0.63 pCi/L, or 13x higher than the EWG health guideline.

Trihalomethanes are contaminants that, like haloacetic acids, form during water treatment with chlorine and other disinfectants. They are a grouping of four chemicals:

• Chloroform
• Bromodichloromethane
• Dibromochloromethane
• Bromoform

These disinfectant byproducts can increase the risk of bladder cancer and liver, kidney and intestinal tumors. They can also lead to problems during pregnancy, including spontaneous miscarriage, cardiovascular defects, neural tube defects and low birth weight.

The EPA sets the legal limit for these contaminants at 80 ppb, while the EWG sets it at 15 ppb. A recent test showed a total of 29.3 ppb, which is 195x higher than the EWG health guideline.

Three out of the four trihalomethanes tested also exceeded EWG guidelines. The only one that did not was bromoform. Here are the totals for the other three:

• Bromodichloromethane – 7.35 ppb (123x higher than the EWG guideline)
• Chloroform – 18.9 ppb (47x higher than the EWG guideline)
• Dibromochloromethane – 82 ppb (28x higher than the EWG guideline)