Conventionally used spectrometric techniques of inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma optical emission spectrometry (ICP-MS) usually involve time-consuming sample preparation procedure of a sample dissolution which requires the usage of aggressive and toxic chemicals. The need for suitable and sustainable analytical methods for direct multi-elemental analysis of plant samples has been increased in recent years. Spectrometric techniques for direct sample analysis, instrumental neutron activation analysis (INAA) and X-ray fluorescence (XRF) have been applied in environmental studies and various fields of screening tests. Nevertheless, these techniques are not commonly used for plant sample analysis and their performances need to be evaluated. This research aimed to assess how reliable non-destructive techniques are in the determination of elements in plants compared to conventionally used spectrometric techniques. A total of 49 plant samples of four conifer species (Pinus nigra, Abies alba, Taxus baccata and Larix decidua) were measured using two conventionally applied (ICP-MS, ICP-OES) and two non-destructive techniques (wavelength dispersive XRF (WD-XRF), INAA). The comparison was performed by investigation of relative ratios of concentrations and by correlation analysis. Moreover, precision of the techniques was examined and compared. The quality control included analysis of NIST pine needles certified reference material (1575a) using all examined techniques. Our results suggest that additional analytical and quality control steps are necessary for reaching the highest accuracy of multi-elemental analysis.

Peloids are natural materials widely used in balneotherapy and dermatological treatments because of their physicochemical and mineralogical properties. Despite Serbia’s long tradition of spa-based pelotherapy, comprehensive data on the chemical and radiological characteristics of local peloids remain limited. In this study, peloid samples from 13 spa locations across four regions of Serbia were systematically investigated. The aim was to determine their physicochemical properties, elemental composition, and natural radioactivity, to assess their suitability and safety for therapeutic use. The analyzed samples exhibited pronounced variability in pH (6.59–9.52), electrical conductivity (77.5–6610 μS/cm), salinity (below detection limit to 4%), and total dissolved solids, reflecting diverse geological and hydrochemical properties. Inductively coupled plasma optical emission spectrometry revealed site-specific variations in macro- and microelements, influenced primarily by local lithology and sedimentary environments, with limited indications of anthropogenic inputs. Gamma spectrometric analysis showed that the activity concentrations of naturally occurring radionuclides (²²⁶Ra, ²³²Th, ⁴⁰K, ²³⁸U, ²³⁵U, ²¹⁰Pb) were within ranges commonly reported for therapeutic muds worldwide, while anthropogenic ¹³⁷Cs was generally low. Radiological hazard indices were below internationally recommended safety limits. A preliminary screening of dermal exposure to potentially toxic elements indicated no significant noncarcinogenic risk (HI < 1) and acceptable carcinogenic risk (TCR) levels. Overall, this study provides a comprehensive chemical and radiological baseline for Serbian peloids, supporting their safe use in controlled therapeutic and wellness applications and highlighting the importance of site-specific characterization for quality assessment.