Appendix VI.

This list is intended as a guide to owners or operators of treatment, storage and disposal facilities, and to enforcement and permit granting officials, to assist in the selection of appropriate monitoring parameters for specification in the water quality sampling and analysis plan. The Department is not requiring that all facilities use this list, but the Department believes that these are the best leak indicators for the majority of units, especially if the unit contains a variety of wastes. This list is called Leak Detection Analytes and is made up of volatile organics, hazardous metals and pH (hydrogen ion).

Investigations by USEPA's Environmental Monitoring Systems Laboratory in Las Vegas, Nevada, and others, have shown that most (as high as 70 percent) of the compounds leaking from RCRA sites are volatile organics. This preponderance of volatiles is not surprising since these compounds would be more likely to move quickly and easily through the environment given their volatility. Therefore, it is logical to conclude that volatile organics would be among the best indicators for early detection of a release.

The rest of the Leak Detection Analytes list is made up of those metals that are amenable to the basic inductively coupled plasma (icp) scan and pH. The metals were chosen because they make up the second most common group of substances that leak from hazardous waste land disposal units, and therefore, are also expected to be excellent leak indicators. pH was chosen because of its all around utility in environmental monitoring and data interpretation. pH was also chosen because of its ability to indicate leaks that otherwise might not be indicated because no single substance has exceeded a detectable level.