Well study shows arsenic increase in drinking water


An analysis of well water tests by the nonprofit watchdog group Raritan Headwaters has detected a disturbing increase in concentrations of arsenic, a known carcinogen.

Raritan Headwaters (RHA) recently analyzed data from over 30 years of well testing within its 470-square-mile watershed in Hunterdon, Somerset and Morris counties. Among the study’s findings was that the percentage of wells with high levels of arsenic rose significantly from 2003 to 2015, the period for which arsenic testing records were available.

“Residents need to know that if they get their drinking water from a well, they should test it to protect their family’s health,” said Cindy Ehrenclou, executive director of Raritan Headwaters. “Arsenic can be filtered from drinking water, but first you have to know it’s there.”

Arsenic is a metal that occurs naturally in certain layers of bedrock, especially those found in New Jersey’s Piedmont region. It was once used in pesticides, and traces often linger in soils on current and former farm fields. It also is found in wood preservatives.

Under New Jersey standards, a concentration of arsenic exceeding 0.005 milligrams per liter of water (mg/L), or 5 parts per billion, is considered unacceptable. Exposure to arsenic is known to cause liver, kidney, colon and bone cancers, as well as gastrointestinal ailments, diabetes and cardiovascular impacts.

The annual well failure rate for arsenic also showed an increasing trend watershed wide. Over 16 percent of wells tested for arsenic failed to meet the state’s drinking water standard.

14,000 Records Analyzed

The increasing concentrations of arsenic were discovered during an analysis of private well tests conducted from the early 1980s through 2015. Dr. Kristi MacDonald, RHA’s Director of Science, studied the results of over 14,000 individual tests conducted in 17 municipalities, looking for trends and changes that take place slowly over time.

All of the towns that show increasing arsenic concentrations in well water are located in Hunterdon County. However, well owners throughout the watershed should be aware of the potential hazard in their towns.

“A lot of people in our watershed are not aware that arsenic could be in their drinking water,” said Bill Kibler, RHA’s policy director. “People tend to assume that because their well water is deep underground, it’s safe from contamination. That’s not always the case.”

Further investigation will be needed to determine why arsenic concentrations are rising, but MacDonald and Kibler believe land disturbance and development may be a factor.

“When we get to the root cause, we could find it’s something that humans are doing,” MacDonald said.

“Collectively, we as residents of New Jersey need to know why this is happening,” added Kibler. “The fact that arsenic is being released from the geology into the water column is not a natural occurrence.”

80 Percent of Residents Use Wells

Four out of five residents of the North and South Branch Raritan watershed region – about 320,000 people – obtain their drinking water from the ground through wells.

Well water tests have been offered since the 1970s by the South Branch Watershed Association and Upper Raritan Watershed Association, which merged in 2011 to form Raritan Headwaters. The tests are entirely voluntary and participant information is confidential.

According to MacDonald, there are many groundwater contaminants that can pose public health risks, including coliform bacteria, nitrate, lead, arsenic, radon and volatile organic compounds (VOCs). Residents who have their well water tested choose which contaminants to test for.

MacDonald noted that most opt to test only for coliform bacteria and nitrate, with far fewer testing for the full range of potential contaminants.

Unfortunately, she said, 80 percent of watershed residents with private wells have never tested their water. And of those who have, most only tested their well water once – not realizing the need to re-test in subsequent years.

“No law requires that homeowners test their wells except when selling their property to someone else, a requirement to protect the buyer only,” noted Dr. Daniel Van Abs, associate research professor for Water, Society and Environment at the Rutgers School of Environmental and Biological Sciences.

‘Out of Sight, Out of Mind’

The analysis was peer reviewed by Dr. Richard Lathrop, professor of environmental monitoring and restoration ecology at Rutgers University’s School of Environmental and Biological Sciences.

”Groundwater is often out of sight, out of mind. But in many places in New Jersey, especially in rural and even in some suburban areas, groundwater is the principal source of drinking water,” said Dr. Lathrop. “Comprehensive analyses of well test data, such as the one undertaken by Dr. MacDonald, are vital to uncover spatial patterns and temporal trends of possible contamination that wouldn’t be detected looking at only one well at one date in time.”

Dr. Lathrop agreed with Raritan Headwaters that further investigation is needed.

“The results pointing to increasing concentrations of arsenic in groundwater are concerning and should be followed up to determine if the trend is real or some artifact of a change in collection or chemical laboratory procedures,” he said. “If real, further work is warranted to investigate potential causal factors and ascertain what the public health implications might be.”

Van Abs concurred. “Most of the findings match more recent information from the N.J. Department of Environmental Protection, but for many towns there is a disturbing increase in arsenic, a natural poison,” he said. “We need to know whether this increase reflects changes in ground water conditions, and if so, why. The report provides important information that should help New Jersey focus efforts to better understand and protect aquifer quality.”

Other Study Results

MacDonald’s analysis also looked for trends in other contaminants. Here are the results:

  • Concentration of nitrate also increased in the watershed during the period for which records are available, 1984–2015. The percentage of wells that failed for coliform – that is, those that showed presence of coliform bacteria in a water sample – increased slightly in the watershed between 1984 and 2015.
  • Concentration of lead did not exhibit any particular trend except in one township in the watershed region, which showed an increase. Radon did not exhibit a trend at the watershed level between 2011 and 2015, the years for which records were available.

How to Get Your Water Tested

Raritan Headwaters provides discounted well testing to residents of its watershed region.

Test My Well