1. APHA (1998) Standard Methods for the Examination of Water and Waste Water, 20th edn. American Public Health Association, Washington DC.
2. USEPA Method 3050B (1996) Acid digestion of sediments, sludges, and soils.
3. USEPA Method 3010A (1992) Acid digestion of aqueous samples and extracts for total metal for analysis of by FLAA or ICP- Spectroscopy.
4. USEPA, National primary drinking water regulations, EPA-816-F-09-004 (2009).World Health Organization (1986) WHO Handbook. WHO, Geneva.