One‐Time Dormant Season Application of Gas Well Brine on Forest Land

Abstract

AbstractGas well brine was applied to forest land at loading rates of 1.52, 0.69, and 0.17 kg Cl m−2 of ground surface in November 1985 to test the feasibility of one‐time, dormant season brine applications on forest land. The number and species of woody and herbaceous plants on the treated plots and adjacent control plot were measured in July 1985 and July 1986. Both pan and suction lysimeters were used to follow changes in macro‐ and micropore soil water chemistry, respectively, at 70‐cm soil depths. Little mortality of overstory trees occurred in any of the treatments, but the number of understory red maple (Acer rubrum L.) and flowering dogwood (Cornus florida L.) saplings was reduced 30 to 40% on the plot receiving 1.52 kg Cl m−2. Several species of herbaceous plants were also eliminated from all treated plots; however, the majority of understory woody and herbaceous plants survived. Chloride, Ba, Pb, As, Se, and Cd were found in soil water at 70‐cm depths at concentrations exceeding Safe Drinking Water Act limits immediately after brine application. Concentrations of elements in macropore soil water declined to safe levels within 3 mo of treatment, except for Se. Micropore soil water, extracted under negative pressures, remained at or slightly above Safe Drinking Water Act limits for As, Se, Ba, and Cd 8 mo after treatment. Mobility of Pb and Cd in the soil appeared to be enhanced by complexation of these metals with Cl in the brine.