What Do these Water Test Results Mean?

Over the weekend I received several water analysis reports from people who had contacted me through the Rural Household Water Quality program. The extent of the testing varied among the reports. One of the broadest reports was from someone who had purchased the WaterCheck plus pesticides package from National Testing Laboratories, Ltd. This test covers 107 different items; 22 metals, 7 inorganic chemicals, 5 physical factors, 5 trihalo methanes, 47 volatile organic chemicals (solvents), and 20 pesticides, herbicides, organices and PCB’s and bacteria tests. The Minimum Detection Levels, which are the lowest levels at which the laboratory detects that contaminant are below the levels established by the Safe Drinking Water Act, so this relatively affordable test will serve as a broad screen of drinking water.

In order to determine if a finding is a problem or of concern, water test results should be compared to a standard. The standard most commonly used is the U.S.EPA Safe Drinking Water Act (SDW) limits. Though private wells do not fall under the regulatory authority of the U.S. Environmental Protection Agency (EPA) or the Safe Drinking Water Act, we can use the standards that we use for comparison. Primary standards are ones that can impact health. Secondary standards impact taste or the appearance of the water. There were some findings that are not regulated under the Safe Drinking Water Act.

The WaterCheck with Pesticides test results showed levels of: iron, manganese, turbidity and hardness that were quite high-exceeding the EPA Safe Drinking Water Act secondary standards. These should be address to make the water more acceptable. Detectable levels of copper, calcium, lead, lithium magnesium nickel, potassium, silica, sodium, strontium, zinc, alkalinity as CaCO3, sulfate, chloride, methyl-ethyl ketone, and tetrahydrofuran. The pH was at the low end of the normal range, and the turbidity was very high. All other substance tested for were non-detect. .

Water quality is driven by geology, well construction, age and condition, nearby sources of contamination, and, within the home, water treatment devices and composition of plumbing materials. The type, age, depth of the well, and the recharge rate are unreported.

Methyl-ethyl ketone, (MEK) and tetrahydrofuran are organic solvents. Methyl-ethyl ketone has no EPA MCL limit and the absolute level of MEK was not high at 70 parts per billion compared to the workplace exposure Threshold Limit Value (TLV) 200 parts per million. Though EPA does not have a MCL for Tetrahydrofuran, the state of Minnesota does at 600 parts per billion. Minnesota has found that their regional groundwater had tetrahydrofuran contamination and worked with state and federal agencies to determine a safe level. The well water tested had Tetrahydrofuran at 90 parts per billion. An acceptable exposure level. The question is how were these chemicals introduced into the groundwater.

Though traces of copper, calcium, lead, lithium magnesium nickel, potassium, silica, sodium, strontium, zinc, alkalinity as CaCO3, sulfate, chloride were found, none of the levels of contaminants were above the MCLs or SMCLs of the Safe Drinking Water Act so would be acceptable for public drinking water supplies. Though the water sample from the point tested was below the MCL for lead of 15 ppb, I am one of the many who believe that there is no safe level for lead. The level found was 5 parts per billion and could have been a first flush sample from a home that has not be occupied for some time. A filter that removes lead should be considered for drinking water.

As stated before test results found levels of: iron at more than 3 times the EPA Safe Drinking Water Act secondary standards and manganese at almost 30 times the EPA Safe Drinking Water Act secondary standards, turbidity was 13 times the standard and the water tested as very hard. In addition, the home purchaser reported that the “water smells like sulphur in the house and very annoying.” I assumed that the purchaser had a hydrogen sulfide problem, but the sulfate results bring that into question. However, the water was not tested for hydrogen sulfide.

Some of the weirdest water problems turn out to be iron or reducing bacteria. Generally, iron bacteria produce unpleasant tastes and odors commonly reported as: "swampy," "oily or petroleum," "cucumber," "sewage," "rotten vegetation," or "musty." The taste or odor may be more noticeable after the water has not been used for some time and are not easily explained by other causes. These bacteria when exposed to sulfate can also produce the characteristic rotten egg smell. There is often a discoloration of the water with the iron bacteria. Though the most classic symptom of iron bacteria is a rust colored slime, it may be yellow, brown, or grey if exposed to manganese or sulfate. It is sometimes possible to see a rainbow colored, oil-like sheen on the water. A quick screen for iron bacteria would be to feel the rubber flapper in your toilet tanks. The iron bacteria tends to accumulate there. (This will not work if there is a water softener in the house- the slime will be there, not in the toilets.)

Turbidity is a measure of the degree to which the water loses its transparency due to the presence of suspended particulates. The more total suspended solids in the water, the murkier it seems and the higher the turbidity. Turbidity can be caused by silica, soil finds or iron bacteria.

On Wednesday, we'll talk about the options for treatment.