Organophosphorus compounds (OPs), which are a wide class of chemical compounds containing organic moieties usually bonded directly to phosphorus or bonded through a heteroatom, such as sulfur, oxygen or nitrogen, are some of the most common chemicals in the human environment. Because of their unique properties and high biological activity, they have largely been used worldwide in agricultural (pesticides), industrial (production of lubricants, hydraulic fluids, and plastics materials), medicinal (drugs against osteoporosis, anticancer and antiviral compounds) or veterinary (anthelmintics) applications. For example, Bisphosphonates are currently the most important and effective class of drugs developed for the treatment of metabolic bone disorders associated with increased osteoclast-mediated bone resorption, such as osteoporosis.