  We calculate the effect of variation in the light-current quark mass, $m_q$,
on standard big bang nucleosynthesis. A change in $m_q$ at during the era of
nucleosynthesis affects nuclear reaction rates, and hence primordial
abundances, via changes the binding energies of light nuclei. It is found that
a relative variation of $\delta m_q/m_q = 0.016 \pm 0.005$ provides better
agreement between observed primordial abundances and those predicted by theory.
This is largely due to resolution of the existing discrepancies for 7Li.
However this method ignores possible changes in the position of resonances in
nuclear reactions. The predicted 7Li abundance has a strong dependence on the
cross-section of the resonant reactions 3He(d,p)4He and t(d,n)4He. We show that
changes in $m_q$ at the time of BBN could shift the position of these
resonances away from the Gamow window and lead to an increased production of
7Li, exacerbating the lithium problem.
