Furthermore, there is ample evidence from research conducted during the past decade showing that some chemicals have potent effects on wildlife at concentrations far below one ppb. Another problem resulting from drugs in the environment is bacteria developing resistance to antibiotics. The general problem of antibiotic-resistant bacteria has been recognized for more than a decade. Antibiotics are only useful to humans so long as bacteria do not become resistant to their effects. Bacteria exposed to antibiotics in sewage sludge or water have an opportunity to develop resistance.
Sewage sludge provides a major pathway by which drugs enter the environment.
Until the drug problem is understood and controlled, it provides a solid scientific rationale for labeling sewage sludge a dangerous soil amendment, the use of which should be forbidden. For a long time, people have worried that the world was going to run out of natural resources. It is now apparent that we have run out places to throw things away. From the viewpoint of disposal, not many decades ago the world still looked pretty empty. Today there can be no doubt that the world is full full of people armed with double-edged technologies.