in CBM produced water can be toxic to some freshwater organisms. Most laboratory comparisons are based on mean concentrations of discharges of CBM produced waters and on direct and prolonged exposure of conventional laboratory test species to undiluted, untreated CBM produced water or its constituents.
To date, widespread adverse effects on indigenous organisms and vegetation as a result of changes in surface water chemistry due to CBM produced water discharges in the field have not been widely studied or demonstrated. A few field tests conducted in the Powder River Basin showed mortality to some species when levels of bicarbonate exceeded the thresholds established in laboratory tests, while two other field studies noted difficulty in identifying any direct effects of CBM discharges on fish assemblages. Studies to evaluate the extent and persistence of changes in water chemistry and ecological effects on indigenous species and hydrological systems in the field, including perennial riparian vegetation, stream hydrological function, stream channel geomorphology, macro-invertebrates, nutrient loading, and fisheries, should be conducted. The results should be used as input to review and enhance, as needed, CBM produced water management, treatment, and disposal requirements.
At the federal level, the requirements associated with leasing and permitting CBM operations on federally managed public lands through the BLM and the protection of water resources under the jurisdiction of the Environmental Protection Agency (EPA) are relatively broad but clear. State regulations regarding treatment and management of CBM produced water differ among the states examined in this study, as do the degrees to which the states have been delegated primacy by federal agencies for permitting and regulating management of CBM produced water. Recognizing the jurisdiction of Indian tribes in regulating CBM development and in CBM produced water management is also important. Surface water discharges of produced water on federal, state, tribal, and private lands is typically managed by state or tribal primacy programs under the Clean Water Act, while discharges to the subsurface environment, including deep-well reinjection and subsurface drip irrigation, are typically managed under the Safe Drinking Water Act by state or tribal primacy programs.
At present, a challenge to the effective management of produced water is the inconsistency in the regulatory consideration and legal description of CBM produced water as a waste or as a resource and the inconsistent definition of terms such as “beneficial use.” CBM produced water volumes change over time and eventually decrease to near zero as CBM fields mature, making sustainability of the water resource an issue to consider for beneficial use opportunities. The committee concludes that management of CBM produced water is