Analysis of potentially toxic elements (PTEs) in lichens using neutron activation analysis (NAA) as a primary method and comparison with a digestion/ICP-MS analysis protocol

Lichens are widely used as biomonitors for assessing environmental baselines for stress or recovery of nutrients and potentially toxic elements (PTEs). In this study, lichens were analyzed using neutron activation analysis (NAA) as a primary method, and compared to a digestion-ICP-MS protocol in two independent laboratories. Three fruticose lichens were analyzed: two were collected near Sudbury (Ontario, Canada) and a certified reference material (CRM) lichen (BCR 482). NAA routinely quantified 22 elements in the samples, and generally agreed with the certified and indicative CRM values, except for Co. Inter-methods comparisons had a strong linearity (R ²  > 0.93) for all three lichens. A lower slope (0.7257) for one of the lichens ( Cladonia spp. ) suggested a low digestion recovery relative to NAA. Overall, NAA was a robust primary method for multi-element lichen analysis, especially trace and minor elements, with minimal sample preparation.