11.   In Westport, six students in the Water Works Group helped persuade parents to repair septic systems that are discharging harmful substances into the river.

12.   Phoenix filters its water of microbes and other harmful substances, as is required by the federal government.

13.   Researchers are trying to determine whether harmful substances in the environment play a part.

14.   Some tears lubricate the eye, removing harmful substances.

15.   The men were convicted two weeks ago on these and lesser charges, notably mixing a harmful substance in a drink.

16.   The most comprehensive study yet of levels of potentially harmful substances in Americans has some encouraging findings and some surprising ones.

17.   The most controversial suggestion was to insist that the link between the environment and breast cancer need not be proved conclusively before governments act to ban potentially harmful substances.

18.   Dureza urged the miners, mostly farmers looking for additional income, to shift to alternative, less harmful substances.

19.   Goals include eliminating waste and potentially harmful substances from manufacturing, and designing products that can recycled or safely disposed.