  The experimental search for the chiral magnetic effect in heavy-ion
collisions is based on charge dependent correlations between emitted particles.
Recently, a sensitive observable comparing event-by-event distributions of the
charge splitting projected on the directions along and perpendicular to the
direction of the elliptic flow has been proposed. The results of a
3+1-dimensional hydrodynamic model show that the preliminary experimental data
of the STAR Collaboration can be explained as due to background effects, such
as resonance decays and local charge conservation in the particle production. A
related observable based on the third order harmonic flow is proposed to
further investigate such background effects in charge dependent correlations.
