Property devaluation is usually not a sufficient reason to have a colorable claim by which to sue the county but you may wish to try, especially if garbage encroaches on your property or noxious fumes do as well.  You may have air rights you can enforce.  The best thing to do is contact local counsel, who handles zoning matters.  Then the counsel may first decide to approach local or state politicians to see if the matter can be handled via the individuals who are charged with protecting the residents.  If the county agency responsible for cleaning up or enforcing this matter is not doing its job, then it may very well be a bigger issue than a civil lawsuit.