Phase II ESA Approach Question

[RiMassEngineer]

Hi,

I'm currently in the process of performing a phase II Environmental Site Assessment. The site consists of two lots, a gas station in the front of the property and a larger lot on the side of the gas station that wraps around the gas stations lot. The main issue I'm having is that in the rear of the property there was two buried vehicles in the ground which may or may not still be filled with gasoline or diesel fuel. The rear of the property was also built up on solid debris consisting of mainly metal fencing and posts. The depth of debris is estimated to be a few feet deep with a few feet of fill above it.

My question is what soil and groundwater tests should I be focusing on. In the area of the buried vehicles I'm planning on testing for VOC's and RCRA-8 Metals. These locations would also serve to hopefully catch any migrating contaminants from the gas station to the other property.

In order to keep costs down I'm planning on only performing TPH tests on soil and groundwater in the front of the property.

If anyone would have a different approach, I would appreciate the input.

Thanks,

Jr.

 

[BenJohnson]

Unless the groundwater is very shallow, the chances of you finding something in the water is pretty slim. If gasoline did reach the groundwater, it would have migrated away from the site years ago. However testing for VOCs is probably prudent. Make sure you check other records in the area to see if some ambient level of VOCs already exist.

I think you are going to have better luck testing the soil beneath the buried car. A lab can mix the soil with distilled water and check to see if any chemicals related to the discarded car can be found. If any suspicion exists that the soil may be contaminated, then it can be excavated and filled with clean backfill.

You should approach this one step at a time. Test the water, test the soil. If nothing is found, then I think you are justified in concluding that the car did not pollute the environment.

Later, during the hearing process, if someone says more tests are required - then do the additional testing. But remember you can spend a lot of time and money to find a problem if it doesn't exist. Don't start running in that regulatory hampster wheel.

 

[bimr]

The assessment should be prepared in general accordance with ASTM E1903 - 11 Standard Practice for Environmental Site Assessments: Phase II Environmental Site Assessment Process

Level of Assessment—Phase II ESAs do not generally require an exhaustive assessment of environmental conditions on a property. There is a point at which the cost of information obtained and the time required to obtain it outweigh the benefit of the information and, in the context of private transactions and contractual responsibilities, may become a material detriment to the orderly conduct of business. If the presence of target analytes is confirmed on a property, the extent of further assessment is a function of the degree of confidence required and the degree of uncertainty acceptable in relation to the objectives of the assessment.

For a gas station project of this type, it is typical to use 5 borings to a depth of 15 to 20 feet below grade. Four borings are typically drilled at the corners of the property and one boring is drilled between the pump islands. Soil samples are generally recovered at 2 foot intervals using a split-spoon sampler and visually classified. The soil samples should be analyzed for combustible vapor concentrations using a portable hydrocarbon surveyor, calibrated to hexane. The soil samples should be analyzed for concentrations of benzene, toluene, ethylbenzene, xylenes (BTEX).

Install groundwater monitoring wells in three of the borings to monitor groundwater levels. After well development, take groundwater samples from each of the three monitoring wells and submit for laboratory analysis. The groundwater samples should be analyzed for concentrations of benzene, toluene, ethylbenzene, xylenes (BTEX).

Not sure that testing for the RCRA-8 Metals would have any merit. Your report will note the existing site history and fill materials used. The bigger concern is the potential for hydrocarbons moving offsite.

 

[RiMassEngineer]

Thanks for the responses guys much appreciated.

The gas station has actually undergone remediation in the past and in 2010 the soils on the property were deemed to be below regulatory standards and no further action was required, monitoring wells on the site were closed. I'm only placing borings on the adjacent property as of now to see if the contaminants migrated down gradient to the larger property.

I was planning on testing for RCRA-8 Metals to see if any lead paint which had been used during the time had leached into the soil or ground water in the area where the solid debris was buried, is that a reasonable approach. Or is buried metal something that doesn't require testing, just simply excavating and removal?

So basically it sounds like i should be testing strictly for VOC's.

 

[bimr]

For a small site, it will probably be more effective to remove lead than to try to remediate, fixate, or whatever.

A Toxicity Characteristic Leaching Procedure test is then a more useful test because it will be helpful in determining disposal options.