Passive groundwater sampling is an increasingly popular sampling method. Many firms are adopting passive sampling over traditional methods because of the huge time and cost savings it provides. But how do you know what sites are best suited for passive groundwater sampling techniques?
This article will outline which sites are best suited for passive groundwater sampling, providing insights into why this method delivers exceptional results, and how to determine its suitability for your project.
For more insights check out The Ultimate Guide to Passive Groundwater Sampling
When to Choose Passive Groundwater Sampling
1. Industrial and Commercial Sites
Sites with industrial legacies, like manufacturing plants, chemical storage, and processing facilities, can benefit from the cost savings and minimal site disturbance passive sampling offers. Whether the site is a part of “upstream” contamination source assessments, or it is in active remediation, the cost savings from passive sampling will be a benefit to clients at industrial and commercial sites.
2. Department of Defense (DoD) Sites
Military sites often deal with a range of contaminants, from jet fuels to chlorinated solvents, and more recently PFAS. The large monitoring well networks and scope of work at these military sites makes passive sampling a perfect solution. Many firms and DoD sites have cut their sampling time and costs in half by switching to passive sampling.
3. Solid Waste Sites
Solid waste sites, such as landfills in detection monitoring, are prime candidates for passive sampling. Due to the recurring nature of these sampling events, adding passive samplers to the monitoring program can reduce time on site when volume requirements aren’t too high. A combination of traditional sampling methods and passive methods may be the most efficient way to monitor landfills that have some wells in assessment that require more volume, but still have other wells that can be sampled passively.
4. Mining Sites
Mining operations can result in complex contaminant profiles in groundwater. Passive sampling can be particularly effective due to its ability to operate in remote locations and under harsh conditions where traditional methods might be logistically challenging. A unique passive sampling approach using HydraSleeves connected to drones has also been applied to sample surface water at pit lakes to increase safety at these locations.
5. Other Contaminated Sites
In general, any site with groundwater contamination issues, such as brownfields or other state or federally monitored sites, may be a good fit for passive sampling, especially where long term monitoring programs are established.
Why Passive Sampling Triumphs on These Sites
The advantages of passive sampling are numerous, but they particularly shine on the aforementioned sites due to several key factors:
- Cost Efficiency: Passive sampling is less labor-intensive and can reduce costs related to equipment, personnel, and disposal of purged water.
- Reduced Disturbance: Unlike traditional methods, passive sampling does not require extensive water withdrawal, which can disturb the site’s equilibrium.
- Ease of Deployment: Devices used for passive sampling can be easily deployed and left in situ for extended periods, allowing for reduced mobilizations and time on site.
- Improved Safety: With less equipment and reduced handling of contaminated water, passive sampling enhances safety for field technicians.
Assessing Site Suitability: A Checklist
To determine whether a site is suited for passive groundwater sampling, consider the following:
- Contaminant Type and Sampler Selection: Have you chosen a passive sampler that can sample for your contaminants of concern?
- Hydrogeology: Does the site’s hydrogeology support passive sampling devices? Consider the aquifer’s permeability and the presence of distinct water-bearing zones.
- Accessibility: Can the sampling locations be easily accessed for the deployment and retrieval of passive devices?
- Regulatory Acceptance: Have you discussed using passive samplers on this site with your regulators?
- Project Goals: Are the project’s data quality objectives aligned with the data that passive sampling can provide?
If the answer to most of these questions is yes, passive groundwater sampling could be an excellent choice for your project.
The Path Forward
Choosing the right groundwater sampling method is crucial for the success of any monitoring or remediation project. Passive groundwater sampling is not a one-size-fits-all solution, but for many sites, it offers significant improvements over traditional methods in terms of efficiency, cost, safety, and data quality.
Book a free consultation to learn more about passive sampling and its potential benefits for your projects.
Frequently Asked Questions
Q1: How does the data quality of samples from passive groundwater sampling compare to those obtained from traditional methods in terms of long-term monitoring?
The data quality of passive groundwater sampling is equivalent to that of traditional methods for long-term monitoring. Through dozens of third-party studies, passive sampling has been established as a valid, representative way to sample groundwater. Passive sampling’s consistency is particularly advantageous for long-term monitoring where understanding trends over time is crucial.
Q2: What are the limitations of passive groundwater sampling, and how can they be addressed to ensure the most effective use of this method?
Passive groundwater sampling’s limitation is that it can sample a finite amount of volume at one time, dependent upon the specific monitoring well. Sites sampling for multiple contaminant types per well may require larger volume samples than passive samplers can deliver. However, certain passive samplers can hold up to 2L of water in one sampler, and multiple samplers can be stacked in the well to obtain higher volumes. Therefore, passive sampling is still a viable solution for most projects.
Q3: Can passive groundwater sampling be integrated into existing groundwater monitoring programs that currently use traditional methods, and what would be the steps for a successful integration?
Passive groundwater sampling can be integrated into existing monitoring programs by working with your regulator on an implementation strategy. In many cases, this integration starts with a pilot study that compares the passive sampler results with data obtained from traditional methods. If passive sampling proves effective and is approved, it can be adopted site wide if applicable. Training for field personnel on proper deployment and retrieval techniques, along with understanding the data’s interpretation, is also critical. Finally, updating the monitoring program’s standard operating procedures to include passive sampling will ensure consistency and compliance across the board.