Filamentous fungi native to heavy metals (HMs) contaminated sites have great potential for bioremediation, yet are still often underexploited. This research aimed to assess the HMs resistance and Hg remediation capacity of fungi isolated from the rhizosphere of plants resident on highly Hg-contaminated substrate. Analysis of Hg, Pb, Cu, Zn, and Cd concentrations by X-ray spectrometry generated the ecological risk of the rhizosphere soil. A total of 32 HM-resistant fungal isolates were molecularly identified. Their resistance spectrum for the investigated elements was characterized by tolerance indices (TIs) and minimum inhibitory concentrations (MICs). Clustering analysis of TIs was coupled with isolates’ phylogeny to evaluate HMs resistance patterns. The bioremediation potential of five isolates’ live biomasses, in 100 mg/L Hg²⁺ aqueous solution over 48 h at 120 r/min, was quantified by atomic absorption spectrometry. New species or genera that were previously unrelated to Hg-contaminated substrates were identified. Ascomycota representatives were common, diverse, and exhibited varied HMs resistance spectra, especially towards the elements with ecological risk, in contrast to Mucoromycota-recovered isolates. HMs resistance patterns were similar within phylogenetically related clades, although isolate specific resistance occurred. Cladosporium sp., Didymella glomerata, Fusarium oxysporum, Phoma costaricensis, and Sarocladium kiliense isolates displayed very high MIC (mg/L) for Hg (140–200), in addition to Pb (1568), Cu (381), Zn (2092–2353), or Cd (337). The Hg biosorption capacity of these highly Hg-resistant species ranged from 33.8 to 54.9 mg/g dry weight, with a removal capacity from 47% to 97%. Thus, the fungi identified herein showed great potential as bioremediators for highly Hg-contaminated aqueous substrates.

A highly sensitive method based on UV photochemical vapor generation capacitively coupled plasma microtorch optical emission using a low resolution microspectrometer was developed for total mercury determination in food and water. The method fulfils most of the eco-scale criteria in terms of derivatization and cost-effective miniaturized instrumentation, which are major benefits compared to cold vapor atomic fluorescence spectrometry and inductively coupled plasma optical emission spectrometry. Formic acid was the single reagent used for the extraction of Hg species from solid samples and as a reaction medium for the UV photo-induced cold vapor generation. A 200 mg lyophilized sample was subjected to ultrasonic assisted extraction in 10 mL of HCOOH 98–100% at 50 °C for 3 h, and then on-line derivatization to cold vapor was performed in 0.6 mol L⁻¹ HCOOH. Water and food with low Hg content adjusted in HCOOH 0.6 mol L⁻¹ underwent on-line preconcentration of Hg vapor on a gold filament microcollector. Total Hg was quantified against external standards containing Hg²⁺ by recording emission at 253.652 nm in a low power/Ar consumption (15 W/100 mL min⁻¹) plasma source with a Maya2000 Pro (Ocean Optics) microspectrometer. The proposed method was compared with common laboratory approaches based on derivatization with SnCl₂ and detection by inductively coupled plasma optical emission spectrometry/atomic fluorescence spectrometry, and thermal decomposition atomic absorption spectrometry. The limits of detection obtained without/with preconcentration were 3.5/0.1 ng L⁻¹ in solution and 9/0.25 μg kg⁻¹ in the solid, much better than those in the reference methods. The proposed method was found to be free from interference coming from multimineral matrices and organic matter, and suitable for sample analysis with various matrices as it provided a recovery of Hg without/with preconcentration of 101 ± 7%/101 ± 12% in food and 97 ± 12% in water.

The paper presents a method for Se determination in a wide variety of food and environmental samples by hydride generation high-resolution continuum source quartz furnace atomic absorption spectrometry. The method was found to be free from spectral interference caused by O₂ and H₂O as well as non-spectral interference coming from the mineral matrix. The detection/quantification limits (95% confidence level) were in the range 0.125 ± 0.007/0.377 ± 0.021 μg L⁻¹ and 0.062 ± 0.004/0.188 ± 0.011 mg kg⁻¹ Se in liquid and solid samples, respectively. Recovery in several certified reference materials was 82–110%, while spike recovery of 1 and 5 μg L⁻¹ Se in natural water was 104 ± 11%. The measurement precision on real samples was in the range 3.9–14.1%.