Understanding

As previously reported, many potential toxins are not credible candidates for contaminating a water supply.  The large quantities of toxins required for significant contamination would be undetected.  Taste and/or odor would also be noticed before much damage could be done.

Additionally, many microbial agents are neutralized through the normal water treatment process.  Dilution also reduces the effect of these contaminants on raw water supplies.

In fact, the distribution system may be the most likely candidate for a contamination threat to be carried out.  It is located beyond the treatment process and much closer to the ultimate consumer.

Strategy

On-line monitoring equipment is not generally commercially available to detect all of the contaminants that could be used to attack a water system.  The cost of such equipment is a major deterrent.

Utilities should continue to use existing monitoring equipment for chlorine levels, turbidity levels, pH, dissolved oxygen and other routine analyses that would show a deviation from normal ranges.  These tests would often indicate that some chemical or biological contaminant had been introduced into the water supply.

Coupled with improved physical protection systems, frequent testing should reduce the potential for a successful contamination attack. Research is also underway on improved monitoring devices (such as microchips) that would immediately alert operators to the presence of biological or chemical contaminants in the water.