  We let $\Omega$ be a bounded domain of $\mathbb{R}^3$ and $\Gamma$ be a
closed curve contained in $\Omega$. We study existence of positive solutions $u
\in H^1_0\left(\Omega\right)$ to the equation $$ -\Delta
u+hu=\lambda\rho^{-s_1}_\Gamma u^{5-2s_1}+\rho^{-s_2}_\Gamma u^{5-2s_2} \qquad
\textrm{ in } \Omega $$ where $h$ is a continuous function and $\rho_\Gamma$ is
the distance function to $\Gamma$. We prove existence of solutions depending on
the regular part of the Green function of linear operator. We prove the
existence of positive mountain pass solutions for this Euler-Lagrange equation
depending on the mass which is the regular part of the Green function of the
linear operator $-\Delta+h$.
