1. MDL- Minimum Detectable Level (The smallest level that can be detected by test).

2. MCL- Maximum Contaminent Level ; In 1974, Congress passed the Safe Drinking Water Act. This law requires EPA to determine safe levels of chemicals in drinking water which do or may cause health problems. These non-enforceable levels, based solely on possible health risks and exposure, are called Maximum Contaminant Level Goals. Based on this MCLG, EPA has set an enforceable standard called a Maximum Contaminant Level. MCLs are set as close to the MCLGs as possible, considering the ability of public water systems to detect and remove contaminants using suitable treatment technologies.