The apparent discrepancy between low and high D abundances derived from QSO spectra may be caused by spatial correlations in the stochastic velocity field .
If one accounts for such correlations , one finds good agreement between different observations and the theoretical predictions for standard big bang nucleosynthesis ( SBBN ) .
In particular , we show that the H+D Ly \alpha profile observed at z _ { a } = 0.7 toward Q 1718+4807 is compatible with 4.1 10 ^ { -5 } \raise 1.29 pt \hbox { $ < $ \kern - 7.5 pt \raise - 4.73 pt \hbox { $ \sim$ } } { % D / H } \raise 1.29 pt \hbox { $ < $ \kern - 7.5 pt \raise - 4.73 pt \hbox { $ \sim$ } } 4.7 1 % 0 ^ { -5 } .
This result is consistent with our previous D/H determination for the z _ { a } = 2.504 system toward Q 1009+2956 and , thus , supports SBBN .