1.   However, Nelson et al showed that colonised patients could contaminate their environment.

2.   Hexaflumuron does not contaminate the environment because it does not penetrate into the surrounding earth.

3.   Hexaflumuron does not contaminate the environment because it does not penetrate the surrounding earth.

4.   Sulphur dioxide, a chemical component of acid rain, contaminates the environment and can cause respiratory and other health problems.

5.   The protesters who have destroyed test sites say letting them proceed would allow the escape of transplanted genes from crops to related wild species and contaminate the environment.

6.   The poison does not contaminate the environment, federal officials said, and is unlikely to be eaten by other species.

7.   A court has ruled that three coal-fired power plants in western Turkey must be closed because they contaminated the environment, the Turkish press reported Wednesday.