TCEs and environmental research: is the TCEs concept scientifically fruitful?

Assessment of contamination, mobility and application of selected technology-critical elements as indicators of anthropogenic pollution of bottom sediments

The study investigates the potential of technology-critical elements (TCEs) in the bottom sediments of the Biała Przemsza River as indicators of anthropogenic activities. The mass fractions of TCEs: Ge, Ga, In, Tl, Sb and Te (and other elements) in the sediment were analysed by inductively coupled plasma mass spectrometry with the maximum mass fractions: 2.46, 25.6, 0.528, 27.7, 12.5 and 0.293 mg/kg, respectively. Distribution and identification of TCE sources were supported by statistical analysis (principal component analysis coupled with varimax rotation and hierarchical cluster analysis). Assessments of TCE contamination using the geoaccumulation index, pollution index, contamination factor, enrichment factor and the antimony-to-arsenic ratio highlighted the high contamination of bottom sediments by Sb, Ga, Tl, Cd, As, Zn, Pb and moderate contamination by Co, In and V. Distinct behaviour patterns were observed among TCEs, revealing Sb and Tl as potential indicators of Zn-Pb ore mining activities. Co, V, Ge and, to a lesser extent, Te emerged as promising indicators of coal and coal fly ash effluents. Sequential chemical extraction of TCEs showed that Sb, In and Tl had the highest mobility from sediments. The Risk Assessment Code calculations suggest, that in the Biała Przemsza River bottom sediments, there is an average risk of contamination by As, Tl and Mn. Soluble forms of Tl, Ge, Sb, Te and In were identified in descending order, indicating their bioavailability.

Occurrence and Distribution of Technology-Critical Elements in Recent Freshwater and Marine Pristine Lake Sediments in Croatia: A Case Study

The occurrence and vertical distribution of ten technology critical elements (TCEs) (Li, Nb, Sc, Ga, Y, La, Sb, Ge, Te, and W) were studied in sediment cores collected from remote freshwater and marine lakes (Plitvice, Visovac and Mir Lakes) in three protected areas of Croatia. These environmental archives were used to assess natural TCE levels in lake sediments and temporal trends in historical anthropogenic atmospheric deposition. TCE was determined after complete sediment digestion using high-resolution inductively coupled plasma mass spectrometry (HR ICP-MS). The measured TCE concentrations spanned a wide range, which can be attributed to the varying input of terrigenous material into the studied lake systems. All obtained TCE concentrations were close to natural conditions and therefore could be used as a reference for other equivalent sediment systems in the coming years. The evaluation of anthropogenic influence on TCE concentrations showed a slight anthropogenic enrichment with Sb and Te in the upper sediment layers of some lakes (Plitvice and Mir Lakes), indicating a widespread atmospheric deposition, which, however, cannot be related to the recent increase in the use of TCE in modern technology.