Heavy Metal Analysis

Heavy metal contamination represents one of the most serious safety concerns in herbal drug quality control, arising from soil uptake at the collection or cultivation site, atmospheric deposition, or contamination during processing, and testing for the four principal toxic elements — lead, cadmium, mercury, and arsenic — is mandatory for every herbal drug submission to CDSCO and AYUSH. WHO permitted limits specify lead at no more than ten milligrams per kilogram in crude herb (five milligrams per kilogram in a concentrated extract), cadmium at no more than 0.3 milligrams per kilogram, mercury at no more than 0.5 milligrams per kilogram, and arsenic at no more than three milligrams per kilogram, with testing conventionally performed by atomic absorption spectroscopy or, for the greater sensitivity required at trace levels, inductively coupled plasma mass spectrometry, following an appropriate acid digestion sample preparation step. Heavy metal contamination is of particular historical concern in certain traditional Ayurvedic, Unani, and Siddha preparations that intentionally incorporate metallic or mineral ingredients (bhasmas and similar preparations) as part of classical formulation practice, and such products require specialised analytical protocols and, in some regulatory frameworks, distinct safety justification pathways separate from those applied to purely botanical preparations.