Summary Groundwater safe to drink, no measurable contamination by perchlorate. General Information What is it? Perchlorate is a type of industrial compound that contains the perchlorate ion (ClO4) and that has entered and persisted in groundwater bodies following industrial uses. For example, perchlorate in California has been used in rocket fuel and other propellants and explosives. Leaks, spills and waste disposal have led to the chemicals entering the environment. These chemicals and other related ones have been linked to interference with thyroid function and child-development. Exposure to the chemicals can be through inhalation of contaminated air or dust and drinking water. Target or Desired Condition Because perchlorate compounds are not common in nature, the desired condition is that concentrations in drinking water or waterbodies is zero. A common proxy for zero concentration is “non-detect”, assuming the detection level is below concentrations considered to be harmful to people or nature. Concentrations at or below the detection limit are given a score of 100. The maximum contaminant level (MCL) allowable in California is 6 parts per billion for perchlorate (CA-EPA), while the toxicity target for drinking water is 1 part per billion (CA and USEPA). This is therefore the target “poor condition” and concentrations above 1 ppb are given a score of 0. Concentrations between the detection limit and 1 ppb are given a score proportional to the concentration. Related Links https://www.waterboards.ca.gov/drinking_water/certlic/drinkingwater/Perchlorate…
