A stochastic method, which uses a modified Langevin equation to represent the fluid turbulence seen by the particles, is used to determine the fully-developed concentration profiles that exist for the turbulent flow of a dilute suspension of spheres in a horizontal channel. Particles with a wide range of inertial time constants and settling velocities are studied. The validity of using the Boussinesq approximation to represent turbulent mixing is explored. (C) 2004 Elsevier Ltd. All rights reserved.