When Oil and Water Mix – Groundwater Contamination

Throughout New Jersey, many homeowners depend on groundwater for their drinking supply. Did you know that over 50% of the United States population depends on groundwater for their drinking water? Groundwater is also one of our most important sources of water for irrigation. Groundwater contamination from a leaking underground storage tank threatens the drinking water supply for both human and animal inhabitants.

Unfortunately, groundwater is susceptible to contamination and the estimated 10 million plus underground storage tanks in the United States are one of it’s greatest threats. In areas where population density is high and human use of the land is intensive, groundwater contamination can occur.

What is groundwater?

Groundwater is found underground in the cracks and spaces in soil, sand and rock. It is stored in and moves slowly through geologic formations of soil, sand and rocks called aquifers. Groundwater can be found almost everywhere and the depth where it’s found depends on the height of the water table. The water table may be deep or shallow; and may rise or fall depending on many factors. Heavy rains or melting snow may cause the water table to rise, or heavy pumping of groundwater supplies or a drought may cause the water table to fall.

The speed at which groundwater flows is dependent on the size of the spaces in the soil or rock and how well the spaces are connected. All of these factor into how quickly oil contamination spreads.So while oil leaking from a tank may originally contaminate soil, it has the potential to leach into the underlying groundwater supply especially if the soil is porous and drains easily like the sandy soil found in Southern New Jersey.

Causes of Groundwater Contamination

In the case of contamination by home heating oil or fuel oil, the culprit is often a leaking underground storage tank. As an oil tank ages, it becomes more susceptible to leaking. While newer oil tanks are less likely to leak due to better construction, they are not leak proof.

However, having an above ground oil storage tank isn’t a failsafe measure. A basement oil tank can leak or be overfilled with the oil finding its way into a French drain or sump pump for example. Likewise, an above ground tank stored outside can leak with the possibility of the oil leeching through the soil and into the groundwater or in a worst case scenario, contaminate the well water that is used for the home’s drinking supply. If there is a nearby stream or pond, that can become contaminated as well.

What should I do if I suspect groundwater contamination?

If a leak has been suspected during the excavation of an underground oil tank, the surrounding soil will be tested. If ground water is encountered during the excavation and there is fuel oil or a sheen floating on the water, the floating fuel oil should be recovered. Likewise, if lab results of the soil tests exceed New Jersey Water Quality Standards, a ground water investigation or ground water remediation will be required. If this occurs, the cleanup can become more complex and require oversight by the NJDEP.

How is contaminated groundwater treated?

Depending on the location and severity of contamination, there are a variety of groundwater remediation strategies that can be employed. Quick Environmental works with homeowners and commercial business owners to determine the most cost effective and timely cleanup method for each individual occurrence and works closely with both the NJDEP and PADEP to obtain any required approvals and oversight on the owner’s behalf.

It is crucial that the source of contamination and its movement be controlled as soon as possible to prevent further spread. Once the contaminated groundwater has been controlled, it can be treated. Treatment methods vary depending on the severity of the contamination.

If the area of contaminated groundwater is small, the water can be removed through the use of a vacuum truck. A large hose will be attached to the monitoring well and connects to the truck.

A Pump and Treat System can be used in the case of a larger contaminated area. Contaminated water is removed from the monitoring well and treated on site. The treated water can then be returned to the aquifer.  The contaminated groundwater can also be left in place to dissolve naturally and monitored.

Because every situation is unique, one or more remediation methods may be used with the end goal being a timely, cost effective cleanup that disturbs as little of the surrounding environment as possible and achieves any necessary approvals required by the NJDEP.

Want to learn more? Read our case study to learn how Quick Environmental carries out groundwater remediation. Or contact us today to discuss your needs with our experienced professionals.