The contamination of aquatic sediments by metals is a worldwide phenomenon and its assessment is a fairly complex issue, as numerous factors affect the distribution of particular contaminants in the environment, as well as their bioavailability. Wigry Lake, as the object of this study, is almost a perfect water body for such considerations. It has been well investigated and densely sampled (up to 459 sediment samples). The quantities of seven metals were determined using the atomic absorption spectrometry (AAS) or inductively coupled plasma (ICP)-MS methods, following previous extraction in a microwave oven. The levels of concentration of the examined elements were as follows (min–max (mg·kg⁻¹)): Cd—0.003–3.060; Cr—0.20–22.61; Cu—0.02–59.70; Fe—80–32,857; Mn—18–1698; Pb—7.0–107.5; Zn—3.1–632.1. Significant differences were also registered in terms of particular metal concentrations in different sediment types found at the lake bottom. Five different geochemical backgrounds and sediment quality guidelines implemented in the study enabled a very scrupulous contamination assessment of the lake sediments’ condition, as well as the evaluation of the natural and anthropogenic contribution to the enrichment of examined sediments in metals. Although Wigry Lake is situated in a pristine region, it is still subject to anthropopressure, which seems to be the lowest in respect to Cr and Mn, while the highest in the case of Pb. The chemoecological state of the lake was ultimately assessed as good. The study highlighted the necessity of an integrated approach to the assessment of contamination or pollution in the course of an environmental research.

Purpose The main objective of the study was the determination of the Cd, Cr, Cu, Pb, and Zn distribution in Wigry Lake sediments, as well as the contamination and ecotoxicological risk assessment on the basis of a large data set. Materials and methods Select metal concentrations were determined via AAS or ICP-MS. Contamination assessment was achieved via the implementation of different geochemical background values, selected pollution indices, and by way of comparison with the limit values of the sediment quality guidelines and supported by cartographic methods. Results and discussion Metal concentrations presented in the paper were associated with a specific type of sediment and sedimentation environment. The highest concentrations of metals were found in the fluvial-lacustrine sediment covering the bottom of the bay of eutrophic character. The lowest amounts were found in the lacustrine chalk and clastic sediment present in the littoral parts of the lake, while profundal sediments were more enriched with metals. Studies revealed that the examined metals have mostly natural, but also anthropogenic origin. The assessment of lake sediments, with the use of geochemical background values and different indices, yielded highly diversified results associated with the variability of background values applied in the study. However, ultimately, the Wigry Lake sediments were found to be only slightly contaminated with Cd, Cr, Cu, and Zn, while Pb concentrations were considered to be more disturbing. The potential ecotoxicological risk was assessed as low. Conclusions Particular attention in this study was paid to the significance of the geochemical background values adopted for calculations, which, in the case of Wigry Lake, gave very divergent results. A uniquely large data set facilitated the performance of a thorough analysis of metal distributions in recent lacustrine sediments and highlighted the necessity of using integrated approaches in aquatic ecosystem studies.

Urban rainwater samples, collected in various districts of Kraków during the period from the spring of 2019 to the winter of 2020, were investigated, and relevant risk implications were assessed. The contents of 31 components were determined, including: bacteria, fungi, pH, EC, Cl^-, N-NO₃, P-PO₄, SO₄^2-, SiO₂, K, Mg, Ag, Al, Ba, Ca, Cu, K, Mg, Mo, Na, Pb, Sb, and Zn. The highest contents of the investigated elements were determined in the industrial (eastern) part of Kraków. The values of toxicity potential were <1, indicating a lack of ecological risk. The value of contamination degree indicated moderate rainwater contamination in all analyzed elements (C_deg = 9.44). The total non-carcinogenic risk values, in both adults (hazard quotient (HQ) = 1.38) and children (HQ = 2.54), exceeded the acceptable level of one. Regarding individual elements in dermal contact, the acceptable level of 1 × 10⁻⁶ was exceeded in Pb (adults carcinogenic risk (CR) = 4.87 × 10⁻⁵, children CR = 2.23 × 10⁻⁵). The contents of the analyzed chemical compounds did not exceed the permissible levels adopted for drinking water; however, rainwater was significantly contaminated with respect to its microbiological parameters. Rainwater was suitable for non-potable use.

The discharge of high flood water (2010) into reservoirs located in the Upper Vistula River catchment and into the overloaded Vistula River channel may strongly affect water and sediment quality. To investigate the contamination of the flooded area in the center of Cracow, total of 32 sediment samples were collected along the length of the Vistula River and also from the cross section in the floodplain area. Additionally, 12 samples of the flooded sediments were collected along the Wilga River – a tributary of the Vistula located within the investigated area. The concentrations of Zn, Pb, Cd, Cu, Mn, Zn, and Fe in the bulk samples and size fraction <20 μm were studied. The metals concentration in the Vistula River flood sediment samples varied in wide ranges (mg/kg): Zn 59-1013, Pb 17-263, Cd 2.6-23, Mn 145-469, and Fe 0.70-3.59%, and was considerably higher in the size fraction samples. The concentration of Cu was low and reached up to 40 mg/kg. The highest amount of Zn was found in the sediment sample from the cross section, located 38 m from the Vistula River channel. Three-step sequential extraction revealed the most mobile metals in the sediment fraction <20 μm, which were as follows: Cd (77% of the total amount), Pb (55%), and Zn (42%). The contamination of the Wilga River flood sediments was lower when compared with Vistula River contamination.