  In Riemann-Cartan spacetimes with torsion only its axial covector piece $A$
couples to massive Dirac fields. Using renormalization group arguments, we show
that besides the familiar Riemannian term only the Pontrjagin type four-form
$dA\wedge dA$ does arise additionally in the chiral anomaly, but not the
Nieh-Yan term $d^\star A$, as has been claimed in a recent paper [PRD 55, 7580
(1997)].
