The Ljubljansko polje aquifer, which is the main supply of drinking water for the local population in Ljubljana, Slovenia is highly vulnerable to anthropogenic pollution. In this study, the geochemistry of major constituents including nitrate concentrations and the dual isotopes of nitrate were used to ascertain the spatial distribution of processes and nitrate sources in the groundwater from seven wells at three different water supplies: Kleče, Hrastje and Jarški prod. The groundwater is of the Ca2+-Mg2+-HCO3- type approaching equilibrium with respect to dolomite and are moderately supersaturated with calcite. The groundwater nitrate concentrations ranged from 5.32 to 50.1 mg L-1 and are well above the threshold value for anthropogenic activity (3 mg L-1). The δ15NNO3 values ranged from 1.4 to 9.7‰, while δ18ONO3 values were from 6.3 to 34.6‰. Based on isotope mixing model three sources of nitrate were identified: atmospheric deposition, fertilizers and soil nitrogen. At Kleče 8, Kleče 12 and Jarški prod 3 the low δ15NNO3 and high δ18ONO3 values result from pristine nitrate sources, while in Hrastje 3 and Kleče 11 equal amounts of nitrate derived from soils with mixed fertilization and sewage. The data also indicate that the main sources of high nitrate concentrations in groundwater are from fertilizers and sewage-manure (comprising up to 64%). Such levels occurred in the Hrastje and Kleče 11 wells where precipitation is the main source of groundwater. Nitrate derived from atmospheric deposition accounted for approximately 10% of the nitrate in the groundwater. The message from this study is that to reduce the nitrogen load and improve water quality will involve containment and the careful management of sources from urban and agriculture inputs such as sewage-manure and fertilizers.

Coupled measurements of nitrate (NO3-), nitrogen (N), and oxygen (O) isotopic composition (δ15NNO3 and δ18ONO3) were used to investigate the sources and processes of N cycling, while the microbial source tracking (MST) method was used to identify microbiological pollution in the surface water of the Sava River Basin (SRB) in autumn in 2014 and 2015 during high and low water discharge. Atmospheric nitrate deposition or nitrate-containing fertilizers were found not to be significant sources of riverine nitrate in the SRB. The ranges of isotope values suggest that NO3- in the SRB derives from soil nitrification, sewage, and/or manure, which were further supported by MST analysis. Microbiological indicators show the existence of hotspots of fecal pollution in the SRB, which are human associated. Long-term observations indicate persistent fecal contamination at selected locations caused by continuous discharge of untreated wastewaters into the SRB.

The gastronomic relevance and price of truffles are related mainly to its unique aroma. In this study, we explore the impact that different volatile compounds have on the aroma quality of fresh truffles using gas chromatography-mass spectrometry (GC-MS). Four hundred sixty fresh ascocarps of nine truffle species (Tuber aestivum, Tuber magnatum, Tuber melanosporum, Tuber mesentericum, Tuber brumale, Tuber excavatum, Tuber rufum, Tuber indicum and Tuber macrosporum) harvested in 2018/19 and 2019/2020 from 11 different countries (Slovenia, Croatia, Bosnia in Herzegovina, Macedonia, Italy, Spain, France, United Kingdom, Germany, Poland and China) were collected. Our investigation included the classification of species based on their aroma profile, a study of the differences in the volatile organic composition of truffle species over a geographical area, and, in more detail, a study of T. aestivum from four natural truffle growing sites in Slovenia. Our models can distinguish between groups, with small classification error. These models could form the basis of a predictive framework to detect fraud concerning truffle products and to determine the influence of different growing parameters on the aroma profile of truffles.

The microalgae Spirulina may be a popular dietary supplement rich in essential nutrients and vitamins, but oversight of the supplement industry, in general, remains limited, and increasing incidents of adulteration, misbranding, and undeclared ingredients together with misleading claims create potential risks. In response, this study characterized the elemental, amino acid and fatty acid content of commercially available Spirulina supplements in Slovenia using EDXRF, ICP-MS and GC-MS and compared the results with their nutritional declaration. The gathered data confirm that Spirulina supplements are a good source of calcium (0.15 to 29.5% of RDA), phosphorous (3.36–26.7% of RDA), potassium (0.5 to 7.69% of RDA) and selenium (0.01 to 38.6% of RDA) when consumed within recommended amounts. However, although iron contents were relatively high (7.64 to 316% of RDA), the actual bioavailability of iron was much lower since it was mainly present as the ferric cation. This study also confirms that pure Spirulina supplements are a good source of essential and non-essential amino acids, and ω-6 but not ω-3 polyunsaturated fatty acids. The presence of additives resulted in significant variation in nutrient content and, in some instances, lower product quality. Moreover, a high proportion (86.7%) of inappropriate declarations regarding the elemental content was observed. Overall, the study conclusions underline the need for a stricter control system for Spirulina-based supplements.