Two suspects, aged 46 and 41, have been remanded in custody in Ilia, in the Peloponnese, after appearing in court over allegations of illegal waste dumping, illegal sand mining and violation of forest legislation.
Another four are facing charges in connection with the case.
The six have been charged with forming and participating in a criminal organization designed to make profit at the expense of the environment.
Investigators say their activity dates back to 2010 and involves the illegal disposal of waste in defunct landfills near Ancient Olympia and Floka as well as at the protected oak forest of Foloi in Ilia.
The defendants allegedly also extracted sand from the Alfios River basin and excavated rocks from Mount Lapitha near the protected Kaifas region.
The 46-year-old, who has been identified as Theodoros Karampelas, has also been charged with attempting to kill four police officers in September 2012. The suspect allegedly tried to run over the four with his truck after they signaled him to stop for an inspection of the vehicle, which was later found to be carrying rubbish.
Police have confiscated 10 trucks, six construction vehicles and one tow truck. Authorities, who have already imposed administrative fines of 12,000 euros, are investigating the role of state and municipal officials.