I really appreciate your posting this blog subject. I would ask the neighbors and previous owners what they know. If applicable, go to the Planning and/or Building Department and find out what permits have been issued for that parcel in the past. You might get an indication of what waste products might be on the property. You should also contact your state’s department of the interior or forestry department to see if there are any endangered species, plant or animal, located on the property. Contact the Sheriff’s department to see if there have been any reports of drug manufacturing on the property. If they don’t know, they may be able to direct you to the correct authority. Not all drug manufacturers use stick built houses to do their business (trailers and vans). Also, if there is a stream or creek on the property, you should investigate what is up stream from your property; like a turkey or hog farm or dairy. These may affect the water in the creek upstream, but they may also smell bad coming from the prevailing wind direction. Ask the neighbors.
When some people look at the prospect of owning land, they get wrapped up in the dream of property ownership. The idea of owning a large tract of property can seem very appealing, even if it is of no practical use to them. This kind of trap is especially easy for people to fall into with land because it's a low maintenance property and doesn't seem complicated (even though there are a lot of factors to consider).
After identifying your likely buyers, try to think like them so you can focus your message to convey what they need to know about your property. Have information ready about schools, shopping and other nearby amenities. For developable land you can be prepared with zoning information and insight from local authorities about the location and capacity of water and sewer service. Each property is different, so customize your information for your situation and your targeted buyers.