Field Journal

Jacqueline W. Quinn

Environmental Engineer

I am an environmental engineer and I work specifically in the area of soil and groundwater clean-up. With my job, I have the opportunity to spend time out in the "field" and in the office. Field work is often the most challenging, because this is where real-time decisions are often made. I will be elaborating on a procedure which we commonly do in the field called groundwater sampling.

When NASA was operating in the early 1960’s as part of the Apollo program, the rules which must now be followed for the disposal of waste did not apply. So NASA, like many other industries, used to let a lot of cleaning liquids be disposed of onto the ground. For instance, if a pipe needed to be cleaned, a solvent or cleaning fluid was used to rinse the pipe out and then the cleaning fluid was just allowed to run off the parking lot into the soil and eventually into the groundwater. At the time, this wasn’t a bad thing. The cleaning fluid was gone, as was all the dirt on the pipe, and nobody really cared where the cleaning agent went as long as it wasn’t a problem right then. This is where the phase "out of sight out of mind" applies.

Unfortunately, now we know that a lot of those cleaning fluids we once believed to be benign or harmless in nature are now known to be carcinagenic (cancer causing) to humans and to other animals in the environment. As an environmental engineer for NASA, it is my job to sample and evaluate the groundwater to see if any of these cleaning fluids are present at high enough levels to be harmful to people or to wildlife.

There are a lot of steps which we go through to sample a groundwater well. One of the first things we do is spread out all of our equipment onto a piece of plastic. This sheet of plastic keeps us from dropping anything back onto the ground. After this, we typically take a water level measurement. This tells us how far down from the surface we will find water. On Kennedy Space Center, we typically find groundwater at 1-meter to 2-meters below the land’s surface. In Florida along the coast, it is not uncommon to find groundwater near the surface. In other parts of the country (ie New Mexico), one might not encounter water until 500-meters below the surface . With our groundwater being so shallow, our sampling procedure is rather quick and easy.

Next we would begin to pump the well with a portable pump. A long tube is submerged into the groundwater, and a battery is hooked up to a pump. The pump works by creating a vacuum on one end and sucking the water up into the tube. The water is then emptied from the tube into a bucket. We typically do not take the first drop of water from a well because it will be high in turbidity. Turbidity is a term which applies to high suspended particles in the water. For example, muddy rain water is very turbid because it has a lot of suspended soil particles in the water. Groundwater might also be turbid, and the longer we pump the well, the cleaner the water will become. We don’t want to sample the turbid water because some contaminants will stick to the suspended particles and give us a false indication of how much of the contaminant really exist in the groundwater.

Once the well has been sufficiently pumped or purged to remove turbid or suspended particles, a sample is collect is a small vial or big jar, depending on the type of testing to be performed. If you wanted to check for heavy metals (lead, mercury, chromium, etc.) in the groundwater, then you need a bigger sample volume to send to the lab. If you are looking for what are called volatile constituents, then you need a small sample which must be collected without any air in the sample jar. Volatile constituents are chemicals which easily go into the air. For example, when you go to the gas station, you can usually smell the fumes when you or someone near you is filling the gas tank. This is because gasoline is volatile in nature and will go from a liquid to a gas without much effort. We also describe this as having a low vapor pressure.

Once the samples are collected, they are sent to a laboratory for analysis. We typically do not receive the results for three weeks. We can look at the levels of contaminants in the groundwater and make some decisions about whether clean-up efforts are required at that site.

There are many different ways to sample groundwater, and this is but one. Other methods go through different procedures and sampling routines. Their costs vary and the level of accuracy and the confidence in the data vary according to the sampling technique. It typically takes 30-45 minutes to sample a well on Kennedy Space Center.