Distribution of Pb, Zn and Cd in stream and alluvial sediments in the area with past Zn smelting operations

The sources of Zn, Pb and Cd in alluvial and stream sediments have been studied in the area of historical Zn smelting tradition. 30 samples of stream sediments and samples from 4 alluvial sediment profiles were collected. Fractions 0.125–0.063 and < 0.063 mm were analysed by the means of ICP-MS prior 4-acid digestion. The highest levels of Zn, Cd and Pb were detected in the alluvial sediments in the closest vicinity to the abandoned slag and ore roasting residue waste dumps, reaching 96 and 4520 mg/kg, 522 and 26,800 mg/kg and 3.7 and 31 mg/kg for Pb, Zn and Cd in stream and alluvial sediments, respectively. The Voglajna River then transports contamination particles into the Savinja River, which afterwards flows into the Sava River. Consequently, the anomaly can even be detected in the Sava River, more than 30 km downstream. Higher levels of Pb, Zn and Cd have been found in fraction < 0.063 mm compared to 0.125–0.063 mm fraction. Impacts of historically contaminated soil erosion and in particular the wash-out of Zn-smelting waste from the improperly managed waste dump were recognised as the dominant sources of Zn, Cd and Pb in the stream and alluvial sediments.


Materials and methods
Study area. The beginning of the Zn-smelting operation in Celje dates back to 1873. Initial production facilities were upgraded in 1911 with the construction of a sulphuric acid production plant. The Celje zinc smelter processed mainly the sphalerite ore from Trepča (Serbia) and Titov Vales (Macedonia) mines. The local sources from nearby historical small-scale mines (Litija, Zavrh) were insignificant. The production capacity of the plant was significantly increased after World War II, but in 1970 the zinc smelting plant was shut down due to low prices of Zn and low supply of Zn ore from domestic (Yugoslavian) mines. Zn smelting was replaced by the titanium dioxide and other chemicals production, which have been in operation since then. The environmental legacy of historic Zn smelting in the area is the contaminated soil. The impacts of atmospheric dust emissions from Zn smelter were detected as far as 14-54 km in the attic dust and 9-14 km for Zn in the soil, depending on the direction from the plant 14 . Another legacy of historic Zn smelting is the pyrometallurgical waste deposit built-up (brownfield area) on the right bank of Voglajna River. 1-5 m thick wastes (slag, decayed fireproof material in ovens, tar, ash and other construction and demolition waste) were deposited directly on the alluvial sediments of the Voglajna River, without proper site preparation or measures to prevent PTEs mobilisation. The Pb and Zn contents in the upper anthropogenic soil layer reach 6 and 11% respectively, and Cd levels 344 mg/ kg 15 . The material from this deposit is very likely washed out to the drainage network during high precipitation events.
Other important potential anthropogenic sources of Pb, Zn and Cd in the area are Železarna Štore ironworks, located 2 km southeast from the Zn smelting plant, and two active gypsum deposits in the Bukovžlak area, 2 km east from historic location of Zn smelting plant.
Historical data shows that the Voglajna and Savinja river sediments were enriched with Zn and Cr by a factor of more than 100, while the concentrations of Co, Pb and Cd were enriched by a factor of 25-50, 6 years after the end of Zn smelting in Celje 16 . In the year 2002, the sediments of Voglajna and Savinja showed the highest levels of Pb in the sediments near Štore, while the highest levels of Zn and Cd were detected in the sediments of the Savinja river about 5 km downstream from Celje in Tremerje 17 . A more recent study examining the sediments of the Sava River (Savinja is affluent of Sava) pointed to the increased concentrations of Pb, Zn and Cd in the stream sediments after the confluence of Savinja and Sava Rivers 10 . The most distinguished increase was detected for Cd levels in stream sediments (a fivefold increase compared to the natural geochemical background).
The river Savinja spring is located in the glacial valley of Kamnik-Savinja Alps in the Logarska Valley. The river flows through mountainous landscapes past the towns of Luče and Nazarje before reaching the Celje basin. After Celje, which is the largest town in its course, the river makes a sharp turn towards the south and cuts antecedent valley through the Sava Fold hills, where it flows into the river Sava at the village Zidani Most. The catchment area of the Savinja River basin covers 1864 km 2 and in its 107 km of length, it drops for 750 m 18 . The river Savinja has several tributaries, one of the most important is the Voglajna River.
In the upper mountainous part, the average annual precipitation is 1700 mm, with increased snowfalls in the mountains, while in the middle and the lower part the average precipitation is around 1200 mm 19 . In 2020 the minimum, average and maximum discharge were 9.4, 33.5 and 392 m 3 /s respectively 20 . The Savinja River has an alpine rainfall-snowmelt regime. This regime has two maximums and two minimums. The main maximum occurs in early spring, while the second one is in autumn, usually in November. The main minimum is during the summer, more specifically in August, and the second minimum is in winter. The duration of the winter minimum is shorter 21,22 . The catchment area of the Savinja river is largely covered by forests and agricultural land. The Savinja river shows its torrential character along its entire length, with intense erosion sections in the upper mountainous part, well-developed alluvial plains in the Celje basin and again erosional character in antecedent flow through the Sava fold hills.
The upper part of the Savinja river consists mainly of Triassic carbonate rocks (limestone and dolomite), while in the middle and lower section shales, tuffs, sandstones and claystones prevail 22,23 . Basins are filled with gravel, mainly of carbonate origin. The Voglajna river, with a length of 35 km in its upper reaches, flows in a more clastic environment-predominantly through Miocene sandstone, marl, claystone, with some intermediate sections of older tuff and felsic extrusive igneous rocks (rhyolite, trachyte) 23 (Fig. 1). No larger metal mines are located in the Savinja catchment area, only small scale Sb-Pb-Zn-Fe deposits (Zavrh, Železno, Lepa Njiva, Puharje and Galicija) are present 24 . Their contribution to the elemental levels in stream and alluvial deposits is not expected to be detectable.
Sampling and sample preparation. The  The stream sediment samples represented fine sediments deposited in the active river channels after the last flood event. The material was collected with a spatula and a bucket on at least five different micro-locations on the inner convex river band. The samples were mixed and then stored in a plastic bag. The bucket and spatula were cleaned before the next use to prevent cross-contamination.
Alluvial sediment samples were collected by drilling through sediment accumulations on a convex river band between the river channel and flood protection dyke using a hand auger. The first sample was taken at a depth of 10 cm and the next one every 20 cm thereafter. The depths of the profiles ranged between 90 and 150 cm, depending on the location, and it ended in all cases when gravel river bed or anti-flood structures were reached. To minimise cross-contamination, the auger was cleaned after each collected sample, as well as the bottom of the hole was cleaned of fallen debris before a new sample was taken.
Stream and alluvial sediment samples were processed in the granulometric laboratories at the Geological Survey of Slovenia, where they were dried in the oven at 303 K. Plant remain, rocks, and other debris were removed. Particle aggregates were gently crushed in a ceramic mortar, taking care that skeletal particles remained intact. Dry screening was then carried out to obtain 2 pulps, each containing 5 g of fractions 0.125-0.063 mm and < 0.063 mm, which were afterwards used for elemental analysis.
Inductively coupled plasma mass spectrometry (ICP-MS) was performed after near-total 4-acid digestion at Bureau Veritas Mineral Commodities Laboratories, Vancouver, Canada, according to the international standards   4 and HF to fuming and taken to dryness. The residue is dissolved in HCl. The presence of 60 elements was determined, however, only 3 (Pb, Zn and Cd) are presented in this paper, because only three elements show the largest variations between their natural and anthropogenic distributions. The precision of the elemental analysis was controlled with 15 duplicates for Pb and Cd, and with 16 duplicates for Zn, while the accuracy was determined on the basis of 17 analysis of 7 standard materials (laboratory internal standards OREAS25A-4A, OREAS45E and OREAS45H and the certified reference materials by European Joint Research Centre BCR-723 road dust, BCR-176R fly ash, BCR-320R channel sediment and BCR-142R soil). The calculated quality control parameter for precision is the relative percentage difference (RPD; Eq. 1). CM-measured concentrations, CR-concentrations in the duplicate. The average percent recovery rate (%R) was a measure for the accuracy of chemical analyses (Eq. 2). CM-measured concentrations, CS-known elemental level in the standard. The bias (B) of the analyses was measured by the analysis of 6 blank samples (triple distilled water) and is presented as the average concentration of elements in blanks.

Data analysis.
Basic statistical parameters were calculated for 3 elements in both of the analysed fractions (0.125-0.063 mm and < 0.063 mm) for stream and alluvial sediments of Savinja and Voglajna Rivers. In the case double analysis were made for precision control, the true value was assumed to be the average value of both analyses. www.nature.com/scientificreports/ Several different enrichment ratio (ER) parameters were used to compare measured values with the reference ones. The first one was the ER EU representing enrichment of the Savinja and Voglajna River stream and alluvial sediments with the corresponding European median values 25 ER EU -enrichment ratio of median elemental levels according to the European stream sediment median elemental levels, Md x -median of the corresponding material (stream or alluvial sediment of Savinja or Voglajna) and Md EU -the corresponding European stream sediment median 25 .
The ER frac was calculated by comparing median values for both analysed fractions (Eq. 4).
ER frac -enrichment ratio of median elemental levels in the 0.125-0.063 mm fraction compared to the median elemental levels in the < 0.063 mm fraction.
Md 0.125-0.063 -medial elemental level in the 0.125-0.063 mm fraction. Md <0.063 -median elemental level in the < 0.063 mm fraction. The third ER source represented elemental enrichment downstream of Celje, compared to the estimated natural background levels in this study (Eq. 5).

Pollution indexes.
To assess the state of pollution, the pollution load index (PLI) and the Nemerov index (I N ) were calculated. These indexes are widely used to assess the global pollution level 26 . The PLI proposed by Tomlinson et al. 27 represents the geometric mean of the values of the Single Pollution Index (PI) for several elements, which is used to assess the degree of pollution of individual pollutants in sediments. The PI is the ratio between the specific elemental level in the sediment and the corresponding geochemical background value (Eq. 6). If the value of PLI (Eq. 7) is smaller than 1, the sediment is considered as uncontaminated, while values 1 < PLI < 2 point out to unpolluted to moderately, 2 < PLI < 3 to moderately to highly, 4 < PLI < 5 to highly and PLI > 5 to very highly polluted material 28 . The PI and PLI were calculated by the following equations: PI-single pollution index, PLI-pollution load index, C i -elemental level, C i,background -background elemental level and n-number of elements.
The geoaccumulation index given by Müller 29 is calculated by Eq. 8 and was used for the calculation of Nemerov index (Eq. 9), which is more suitable for the cases where contamination of larger areas are assessed.
I geo -geoaccumulation index, C i -elemental level and C i,background -background elemental level I N -Nemerov index, I geomax -is the maximum I geo and I geoavg -is the average value of I geo . According to Förstner et al. 30 the classification of I N is as follows: 0 < I N ≤ 0.5, uncontaminated; 0.5 < I N ≤ 1, uncontaminated to moderately contaminated; 1 < I N ≤ 2, moderately contaminated; 2 < I N ≤ 3, moderately to heavily contaminated; 3 < I N ≤ 4 heavily contaminated; 4 < I N ≤ 5, heavily to extremely contaminated; and I N > 5, extremely contaminated. Table 2 and Fig. 2 show the descriptive statistical parameters (minimum, maximum and median values) of elemental levels for all samples in two size fractions (0.125-0.063 and < 0.063 mm), the European background levels for stream sediments 25 , estimated background levels for this survey and the quality control parameters (RPD, %R and B). Analytical values are presented in Table S1. The median values of Pb, Zn and Cd of stream sediments are comparable to the corresponding European stream sediment median levels. Alluvial sediments are generally enriched with Pb, Zn and Cd compared to stream sediments. This is especially valid for the Voglajna  (Table 3) show Pb, Zn and Cd enrichments in smaller fraction compared to coarser ones, while the values of ER source show significant enrichments downstream Celje, compared to corresponding upstream values. ER source value for Cd reaches 7.1 in the fraction 0.125-0.063 mm in stream sediments and 15 in the < 0.063 mm fraction in alluvial sediments.

Results
Pb, Zn and Cd levels in Savinja stream sediments in the upper part (until the town of Mozirje) are more or less constant, and corresponding average values can be regarded as the natural background level (Fig. 3). Approaching the town Žalec Pb, Zn and Cd levels start to steadily increase, until the affluent of Voglajna River, where the sharp rise of all three elemental levels has been observed. The highest Pb, Zn and Cd levels in the Savinja River stream sediments were measured in the first two samples, located downstream of the affluent with Voglajna River, reaching 48 and 52, 270 and 270, and 2.0 and 2.3 mg/kg for < 0.063 and 0.125-0.063 mm fractions, respectively (Table 2). Pb, Zn and Cd levels slowly decrease downstream until the affluent with the Sava River. However, background levels are not reached anymore.
A similar pattern is observed in the case of Voglajna River stream sediments (Fig. 3). In the upper part Pb, Zn and Cd levels are comparable to the estimated natural background. A steady rise is observed as the river approach the populated area of Celje. The first increase is observed nearby Štore ironworks, and the second larger increase is observed downstream of the pyrometallurgical waste dump. These are the highest measured Pb, Zn and Cd levels of stream sediments in this study, reaching 89 and 96, 520 and 400, and 3.7 and 2.8 mg/kg for the < 0.063 and 0.125-0.063 mm fractions, respectively ( Table 2).
The samples from alluvial sediment profiles were taken upstream (SP1 and VP1) and downstream (SP2 and VP2) from the pyrometallurgical waste dump. The expected Pb, Zn and Cd levels in profiles SP2 and VP2 should therefore be higher than the corresponding levels in profiles SP1 and VP1. The results show that comparable levels of Pb, Zn and Cd are found in profiles SP1, SP2 and VP1, varying between 18 and 68, 65 and 221 and 0.24 and 1.8 mg/kg for both fractions respectively, while corresponding levels in profile VP2, which is located in the immediate vicinity of the waste deposit are for a magnitude higher (Fig. 4). Pb, Zn and Cd levels in the coarser fraction in the upper part of the profile are around 220, 1500 and 4.6 mg/kg, while in the lower part extreme values were detected (4100, 24,000 and 26 mg/kg, respectively). Pb, Zn and Cd levels in < 0.063 mm fraction in all four profiles are between 20 and 50% higher than corresponding levels in 0.063-0.125 mm fraction (Fig. 4). These results pointed out a dominant anthropogenic source of Pb, Zn and Cd in the stream and alluvial sediments in the study area. Table 2. Descriptive statistical parameters of Pb, Zn and Cd levels (mg/kg) in stream and alluvial sediments collected in Savinja and Voglajna Rivers in two analysed grain size fractions. The presentation format is: minimum value-maximum value (median value), R average percent recovery, ARPD average relative percent difference between double analysis, B bias, N.A. not analysed, S Savinja, V Voglajna, E data from the European stream sediment survey 25 , SS stream sediments, P alluvial sediments, BGV estimated background value from the data in this study (details are shown in Fig. 3).     (Table 4). According to the PLI value, both stream and alluvial sediments of both rivers in their lower part could be regarded as contaminated. The highest values of I N index were detected for Cd, showing that stream sediments can be considered as moderately to heavily contaminated, alluvial sediments of Savinja River as moderately contaminated, while alluvial sediments of Voglajna River as extremely contaminated (Table 4).  In order to determine the significance of detected contamination, maximum Pb, Zn and Cd levels from this study were compared to values, obtained by other studies around the globe ( Table 5). The comparison reveals that maximum Pb, Zn and Cd levels in stream and alluvial sediments of the Savinja River are generally lower than from similar sites around the world. However, the maximum Pb, Zn and Cd levels in alluvial sediments of the Voglajna River are comparable to those found at the most contaminated sites globally.
Pb, Zn and Cd levels in the upper parts of the Savinja and Voglajna Rivers very likely resemble natural background values. The only exception is a slight increase in Pb, Zn and Cd levels in stream sediments at the town Mozirje. Metals, wood and plastic processing industry and agriculture are present there, as well as the emissions from associated traffic, all of them potentially contributing to the metal intake into the drainage network 37,38 . Pb, Zn and Cd levels after the town Mozirje drop to the background levels, so this increase was not found to be of great significance for this study.
Approaching Celje, past the town Šempeter, Pb, Zn and Cd levels begin continously increasing, especially for Pb. This is the area where the river reach basin with more intensive agriculture and urbanisation. River also flows parallel with the main highway connection A1/E57. Discharge from water treatment plants from the A1 motorway, as well as the wash-out of road dust, enriched with Pb, Zn and Cd from other paved areas 39,40 can also be one of the reasons for the increase of these elements in that area 10,41,42 . Farming (especially hop farming) in the lower Savinja basin area can also contribute to the increased values of Pb, Zn and Cd, since fertilizers and phytopharmaceuticals could be enriched with these metals 38,43 .
As the Savinja River approaches the town Celje, the wash-out of the contaminated soil due to atmospheric dust deposition emitted from historical Zn smelter in Celje can be added to the list of potential sources 15,44,45 . The study of Žibret and Šajn 14 in particular discovered that the effect of this smelter in the soil can be detected up to 14 km away. Curiously, Pb, Zn, and Cd levels in alluvial sediments in the Voglajna River follow the same pattern as the Savinja River-it shows a steady increase of Pb, Zn, and Cd levels as the river approaches Celje. The impact of the Štore steel mill also cannot be neglected in this case, as evident from the Fig. 3.
The study of Zhao et al. 9 reported that the wash-out of historically contaminated soil can have a significant impact on the composition of stream sediments and that the highest levels of Zn, Pb and Cd in stream sediments of Baiyin district were detected around the non-ferrous mine and smelter. Huang et al. 46 confirmed that the sediments from Huixian wetlands are 11% more polluted than nearby soils, the reason for this is the soil wash-out from contaminated site, transportation and sedimentation in wetlands downstream. The study of Balabanova et al. 47 reported that particles originating from contaminated soil that enter the Zletovska River due to the nearby Pb-Zn mine, can also be detected several tens of km downstream of the Bregalnica River.

Metal levels downstream pyrometallurgical waste deposit. The spatial distribution of Pb, Zn and
Cd in stream and alluvial sediments clearly reveal that the pivotal source of Pb, Zn and Cd in the alluvial and stream sediments in the study area is the wash-out of contaminated particles from improperly constructed and managed pyrometallurgical waste dump. During the operation of the Zn smelter between 1870 and 1970, a www.nature.com/scientificreports/ large amount of waste was gradually piled up in the surroundings of the former smelter. As a result, slag, ashes, dust, construction waste (fireproof materials i.e. bricks from ovens and similar waste) and tar from the adjacent coking plant can be found throughout the area around Zn smelter 48 . Waste was placed directly on the Voglajna river alluvial sediments (Fig. 5), and it is still not protected from erosion in the case of heavy rain events, while the drainage is also not properly managed. Therefore, it is not a surprise that the highest values of Pb, Zn and Cd in stream and alluvial sediments in this study were found on the sampling point, located in the close vicinity donwnstream of this dump. Zn levels reached 27,000, Pb levels 4500 and Cd levels 32 mg/kg. Such conclusion can be further supported by the individual particle observation under SEM/EDS by comparing particles, carriers of PTEs in stream and alluvial sediments with corresponding particles located in the waste deposit by the future studies. Just a few km downstream of this waste dump, the Voglajna River flows into a larger Savinja River. The impact of intake of contaminated sediments by the Voglajna River is clearly visible also in Savinja case, because the highest recorded Pb, Zn and Cd levels in Savinja River stream sediments are detected just after the confluence between Savinja and Voglajna rivers. Concentrations of investigated elements gradually decrease downstream, but they did not reach values similar as were prior to Celje before the confluence with Sava river. Interestingly, the sharp rise of Pb, Zn and Cd levels in stream sediments of regionally important Sava River can be further detected downstream the confluence with Savinja 10 .
It was discovered by many studies, that improperly managed mining and pyrometallurgical waste dumps can have a serious adverse impact on the composition of stream and alluvial sediments. During the Aznalcóllar dam collapse (Spain) in 1998 around 5 million cubic meters of acid waste from the processing of pyrite ore were released into the environment due to improper tailings management. In addition to the pollution of river sediments, alluvial plain and aquatic wildlife, the waste also entered into Doñana national park 49 . Similar tailing Table 5. Maximum elemental levels in stream and alluvial sediment samples from the present and similar studies globally. AAS atomic absorption spectrometry, FAAS flame absorption atomic spectrometry, ICP-MS inductively coupled plasma mass spectrometry, ICP-AES inductively coupled plasma atomic emission spectrometry, ICP-OES inductively coupled plasma optical emission spectrometry, AR aqua regia digestion, TD total acid digestion.

River, country Fraction size (µm) Chemical analysis
The main anthropogenic source of Pb, Zn and Cd  52 and elsewhere. The fluvial dispersion of pollutants from historical Zn smelting site (at least 30 km away from the source) can therefore be detected over much longer distances compared to the impacts of atmospheric dispersion, which are estimated between 9 and 14 km for Zn and 6 and 32 km for Cd 14 . This result is also in agreement with other studies. Foucher et al. 53 discovered, that the impacts of abandoned Hg mine can be detected even 500 km away from the mine, where the main dispersion mechanism was water transport (river and marine). A similar situation was also found in the study of Periáñez 54 , where coastal waters transported dissolved heavy metals from the Odiel-Tinto rivers as far as 200 km from the source of contamination.
Pb, Zn and Cd levels from alluvial sediment profiles. It was expected that profiles above the sources of contamination (SP1 and VP1) should have lower Pb, Zn and Cd levels than profiles below Celje (SP2 and VP2). Pb, Zn and Cd levels at the upper part of the profile SP1 were slightly increased, which could be attributed to the use of Cd-enriched fertilisers 38 and wash-out of contaminated soil. It was reported that a single flood event can produce a layer of fresh alluvial deposit as thick as 10.7 mm, depending on the frequency of flooding, erosion rate, etc 55 . The distribution of Pb, Zn and Cd levels in the profile SP2 shows that lower levels were detected in upper 50 cm, and sharp rise of pollutant levels in depthts greater than 50 cm. This result can be explained by the sedimentation of around 50 cm of fresh and less uncontaminated alluvial sediment after the cease of Zn production in Celje in 1970 during the floods in 1990, 1998, 2007, 2010, 2012 and 2017 56 . However, Pb, Zn and Cd levels in the lower parts of SP2 profile (below 50 cm) are around two-fold higher than the corresponding levels in stream sediments below Celje, and this material could have been deposited during the Zn-smelting operations between 1870 and 1970.
The vertical distribution of Pb, Zn and Cd in the profile VP2 is similar to that of the SP2 profile, with the difference that they are of a magnitude higher. The material from the upper 50 cm of VP2 profile, which has very high Pb, Zn and Cd levels, was probably deposited after 1970, while the material from the lower part of the profile reaches extreme values and very likely represent the material which was eroded from waste deposit during smelter operations.
The analysis of the construction trenches dug through this waste deposit showed that the area is covered with 0.5-4.7 m thick debris of construction waste, slag, bricks, slags and boilers 57,58 (Fig. 5), which are placed directly www.nature.com/scientificreports/ on the permeable Voglajna river alluvial sediments. The past analysis also shows extreme Pb, Zn and Cd levels in these materials, even those above 1% for Zn 15 , and this data could further support the result of current study, that the major source of Pb, Zn and Cd levels in fluvial sediments of the Voglajna and Savinja rivers is actually the wash-out of the material from waste dump. Pb, Zn and Cd levels in finer fraction < 0.063 mm of alluvial sediments are on average around 30% higher than in coarser fraction 0.125-0.063 mm, while for stream sediments this enrichment is less significant, around 10-15%. This was expected, because the levels of heavy metals in alluvial sediments generally increase with the decreasing particle size 59 .

Conclusions
The focus of the study was to determine the sources of Zn, Cd and Pb in the fluvial system of the Savinja River. Samples of stream sediments were collected from the Savinja and Voglajna rivers source to the river mouths, while the samples of alluvial sediments were collected in alluvial profiles up-and downstream of the main suspected anthropogenic source, the abandoned pyrometallurgical waste deposit in Celje town. The majority of the processed ore in abandoned Zn smelter was imported, and no known larger Pb or Zn mines existed in the area. It was discovered that median values of stream sediments in this study are comparable to those of the representatives of European rivers, while they are generally lower than the values measured next to abandoned mines and smelters worldwide. In the upper parts of the Savinja and Voglajna rivers, Pb, Zn and Cd levels are constant and are clearly pointing to the natural background levels. A steady rise in Pb, Zn and Cd levels is observed as the rivers flow through densely populated areas with intensive agriculture. A sharp rise of Pb, Zn and Cd levels in stream sediments of the Savinja River after the confluence of the Voglajna river has been also observed. According to the geochemical indexes (PLI and I N ) these sediments can be regarded as contaminated. Spatial distribution of measured levels reveals that the material wash-out from the improperly managed pyrometallurgical waste dump can be recognised as the main source of metal pollution of river sediments in this area because extreme values of Pb, Zn and Cd levels in the alluvial sediments of Voglajna River were measured next to this brownfield area. The wash-out from this dump is clearly affecting also the composition of stream sediments in Savinja River downstream the confluence with the Voglajna River. Although the Zn smelter in Celje has been shut down for half a century, the impacts of improper waste management are still present. The results of this study point out the need for proper management of abandoned and active pyrometallurgical and mine waste deposits, particularly for areas that are prone to erosion, to protect both human health and the health of other living organisms downstream.