The DWRLB Chemistry Unit (CU) provides a wide range of testing services for inorganic and organic contaminants in drinking water and drinking water sources. This includes regulated toxic metals (e.g., arsenic, lead, cadmium) determined by sensitive analytical techniques such as Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). ICP-MS is also increasingly used to determine unregulated metals and for quantitation of long-lived radionuclides. CU also determines anions by Ion Chromatography (IC) and Ion Chromatography coupled to Electrospray (ESI) MS and ESI tandem MS. These anions include: common anions (fluoride, chloride, sulfate, nitrate, nitrite, phosphate); disinfection by-products (bromate, chlorite, chlorate); and miscellaneous anions (perchlorate, chromate, hexavalent chromium). General water quality parameters are determined by ion-selective electrode, spectrophotometry, distillation, amperometry, and titration techniques.
DWRLB relies on instrumental analysis to analyze many organic contaminants including gas chromatography, liquid chromatography, and mass spectrometry methods in a variety for forms (e.g. purge & trap GC-MS). Organic contaminant testing includes analyses for federally-regulated and California-only regulated contaminants in drinking water using both the USEPA 500 series methods (approved for drinking water) and the USEPA 600 series methods (for wastewater).