Groundwater Monitoring Procedures Part 2: Equipment and Procedures for Collection of Water-Quality Samples from Monitoring Wells

Abstract

Groundwater-quality data provide essential information for assessing groundwater chemistry and identifying and evaluating trends related to regional hydrogeology, water use, and land use. The Delaware Geological Survey (DGS) has been collecting groundwater samples for various projects over the past several decades. This document serves as a reference for collecting groundwater samples from monitoring wells. The methods described in this report were adopted from published federal agency and industry standard operating procedures and modified to fit DGS-specific practices (USEPA, 2007; USGS, variously dated; SOGW, 2013).

This document describes the sampling procedures used by DGS staff to collect routine groundwater samples from monitoring wells using the traditional purge and grab method. This methodology is only appropriate when sampling for certain analytes (major ions, select metals, physical parameters) and it will not be applicable to sampling for volatile compounds or other constituents for which results may be affected by pumping the well before sampling (purging). Groundwater-sample collection includes two parts – purging the well and collecting the sample. Included in this report are equipment recommendations and step-by-step instructions on site preparation, well purging and sampling, post-sampling protocols, and other considerations.

Along with DGS Groundwater Monitoring Procedures, Part 1 (Andres et al., 2018), this report is part of a series documenting groundwater data-collection protocols used by DGS staff.