After overcoming the financial and access barriers to water testing, one final obstacle remains: interpretation. Fewer entities are willing to interpret water testing results for owners due to liability and the expertise required. Water testing results are legal documents with sometimes pages and pages of quantitative information. However, there is no standard format, units vary from contaminant to contaminant and from report to report, and all interpretation depends on the baseline.
To further complicate interpretation, laboratory quality assurance and quality control results may be included as part of the results. This may manifest as blank results, which involve testing distilled water to ensure that testing equipment and the testing procedure are not causing contamination of samples. Some results on the report may be duplicates which are samples that are split and run twice to ensure the repeatability of results. Also, some results may be for other standard samples of known material not related to the owner’s sample, which are run to ensure the accuracy of results.
In the case of a question of oil and gas operations affecting water quality, meaningful interpretation is only possible through comparison to pre-drilling results. Further, a more robust baseline provides a more nuanced interpretation. For example, post-drilling variations must exceed any historical or natural variations that may be attributed to weather or season. All changes in water quality parameters that exceed safe drinking water standards are important, but not all of them are related to oil and gas operations.
The Penn State Extension has created an online tool to aid in the interpretation of water quality reports.
Images: “PSU interpretation” by Penn State Institutes of Energy and the Environment; “Drinking Water Interpretation Tool” by Penn State Institutes of Energy and the Environment