ARCHIVED REPORTS_XR0011034 - Laserfiche WebLink

Home Browse Search

C112M HILL Standard Operation Procedure (3113195 Version) Groundwater Sampling for Intrinsic Bioremediation Characterizations Section 1. Introduction This document presents a protocol for measurements and groundwater sampling in support of intrinsic bioremediation characterizations. This protocol was developed because of the potential adverse effects of commonly employed groundwater sampling methodology on the quality of intrinsic bioremediation data. Commonly employed sampling collection techniques include use of bailers and excessive rates of groundwater purging. These practices will often produce groundwater samples with a geochemistry that is different than formation groundwater. Parameters for characterization of intrinsic bioremediation are listed in a table at the end of this document. The specific mechanisms r in which the geochemistry of groundwater sample can be altered through sample collection technique include the following: • Excessively lowering the water level in the well by purging at high flow rates. During recharge, exposure of water trickling into the well to the atmosphere can result in aeration of the groundwater sample, resulting in loss of volatiles, introduction of oxygen, and elevation of the sample Eh. • Sample aeration caused by sample collection with a bailer and/or excessive exposure of the groundwater to the atmosphere during field measurements or filling of sample containers. • Increeased turbidity caused by bailing the well, or purging the well at high flow rates creating high entrance velocities through the well screen and mobilizing sediment in the well, sand pack, and formation. The "minimal aeration method" described in this protocol will enable collection of representative groundwater samples for characterization of intrinsic bioremediation, except at those sites of very low permeability. Considerations for very low permeability settings are discussed. SF010030987.DOC D-1