The chronic toxicity of sodium bicarbonate, a major component of coal bed natural gas produced waters

Abstract

Sodium bicarbonate (NaHCO3) is the principal salt in coal bed natural gas produced water from the Powder River Structural Basin, Wyoming, USA, and concentrations of up to 3000 mg NaHCO3/L have been documented at some locations. No adequate studies have been performed to assess the chronic effects of NaHCO3 exposure. The present study was initiated to investigate the chronic toxicity and define sublethal effects at the individual organism level to explain the mechanisms of NaHCO3 toxicity. Three chronic experiments were completed with fathead minnows (Pimephales promelas), 1 with white suckers (Catostomus commersoni), 1 with Ceriodaphnia dubia, and 1 with a freshwater mussel, (Lampsilis siliquoidea). The data demonstrated that approximately 500 mg NaHCO3/L to 1000 mg NaHCO3/L affected all species of experimental aquatic animals in chronic exposure conditions. Freshwater mussels were the least sensitive to NaHCO3 exposure, with a 10-d inhibition concentration that affects 20% of the sample population (IC20) of 952 mg NaHCO3/L. The IC20 for C. dubia was the smallest, at 359 mg NaHCO3/L. A significant decrease in sodium-potassium adenosine triphosphatase (Na(+)/K(+) ATPase) together with the lack of growth effects suggests that Na(+)/K(+) ATPase activity was shut down before the onset of death. Several histological anomalies, including increased incidence of necrotic cells, suggested that fish were adversely affected as a result of exposure to >450 mg NaHCO3/L. This article is a US Government work and is in the public domain in the USA.

Toxicological perspective on the osmoregulation and ionoregulation physiology of major ions by freshwater animals: Teleost fish, crustacea, aquatic insects, and Mollusca

“…Elucidation of the details of this mechanism are needed because HCO 3 − ranked relatively high among the major ions in terms of toxicity [128]. Moreover, HCO 3 − is a primary constituent of produced waters from coalbed natural gas development and effluents from mountaintop mines and valley fills [304,305,322]. …”

“…The 96-h LC50 values for the larval stages (1–22 d posthatch [dph]) of white sucker ( Catostomus commersonii ), fathead minnow, walleye ( Sander vitreus ), rainbow trout, and northern pike ( Esox lucius ), respectively, were estimated as 13.6 mM, 38.5 mM, 58.9 mM, 93.4 mM, and 131.1 mM NaHCO 3 . For fathead minnows, the chronic LC50 for survival at 37 dph was 6.0 mM NaHCO 3 , whereas a 7-d growth test that began with 2-dph larval fish had a 20% effect concentration of 8.2 mM NaHCO 3 [305]. The lower toxicity values appear to result from effects of HCO 3 − rather than Na + .…”

“…Using absence of foot movement during a 5-min observation as the indicator of mortality, the 96-h LC50 and 7-d LC50 for juveniles were 13.8 mM and 12.6mM NaHCO 3 , respectively [304,305]. …”

“…A study of the effects of NaHCO 3 as a constituent of produced water from coalbed natural gas wells included the unionid Lampsilis siliquoidea . Using absence of foot movement during a 5-min observation as the indicator of mortality, the 96-h LC50 and 7-d LC50 for juveniles were 13.8 mM and 12.6mM NaHCO 3 , respectively [ 304 , 305 ].…”

In situ and laboratory toxicity of coalbed natural gas produced waters with elevated sodium bicarbonate

“…Therefore, the survival of early lifestage fish, especially those younger than 6 dph, is likely reduced significantly in the field when concentrations of NaHCO 3 rise to more than 1749 mg/L. Measurements were not made of Na/K adenosine triphosphatase in fish from experiments completed in situ, but the data from Farag and Harper suggest that a significant decrease in Na/K adenosine triphosphatase may have affected the ability of the 2 dph fish to survive in the field.…”