The paper studies a bounded symmetric operator A ε in L 2 (R d ) withhere ε is a small positive parameter. It is assumed that a(x) is a non-negative L 1 (R d ) function such that a(−x) = a(x) and the momentsIt is also assumed that µ(x, y) is Z d -periodic both in x and y function such that µ(x, y) = µ(y, x) and 0 < µ − µ(x, y) µ + < ∞. Our goal is to study the limit behaviour of the resolvent (A ε + I) −1 , as ε → 0. We show that, as ε → 0, the operator (A ε + I) −1 converges in the operator norm in L 2 (R d ) to the resolvent (A 0 +I) −1 of the effective operator A 0 being a second order elliptic differential operator with constant coefficients of the form A 0 = − div g 0 ∇. We then obtain sharp in order estimates of the rate of convergence. R d a(z) dz = 1. On the other hand, each point of γ has a random life time, and the intensity of death is m(x) > 0. In the general case the intensities of birth and death might depend on