Potentially toxic elements in sediments near mines-a comprehensive approach for the assessment of pollution status and associated risk for the surface water environment.

This research is focused on the assessment of the pollution status of river and lake sediments near Pb, Zn, and Cu mines and tailings in the southeastern part of Serbia-Krajiste area. The study is based on hypothesis that investigated rivers and lakes in the Krajiste area could be polluted by potentially toxic elements (PTEs) and that these elements could pose considerable ecological risk to the studied surface water environment. High PTE contents are detected in studied river sediments (up to 7892 mg kg-1 for Zn, 3224 mg kg-1 for Cu, 36,790 mg kg-1 for Pb, 64.2 mg kg-1 for Cd, and 1444 mg kg-1 for As). Given that the contents of the studied elements in most of the river sediments exceeded the background values, values prescribed by regulations of the Republic of Serbia, as well as probable effect concentration (PEL), it is possible to conclude that sediments were heavily polluted and that detrimental effects can be expected. Contamination indices including the enrichment factor (EF), contamination factor (CF), index of geoaccumulation (Igeo), potential ecological risk index (Eri), ecological risk index (RI), pollution load index (PLI), and aggregative toxicity index (ATI) were used to assess the degree of pollution by PTEs. The ecological risk assessment revealed that there is a significant risk observed for toxic elements (primarily Pb, Cu, Cd, and As) at this moment. The highest contamination indices (EF, Igeo, CF, PLI, and ATI) are mainly associated with historical and current mining activities. The Monte Carlo analysis based on the risk assessment indices was used to evaluate the uncertainty. The most pronounced toxic risk is found for the Pb, Cu, Cd, and As which assessment was in the range of high and extremely high-risk probabilities. The obtained results suggest that levels of toxic elements pose a significant ecological risk to the surface water environment near Pb, Zn, and Cu mines in the Krajiste area. The methodology applied in this paper could be very useful for other researchers dealing with the problem of environmental pollution by toxic elements.

Correlation of metals and degraded marine (micro)plastic litter in geologically similar coastal areas with different anthropogenic characteristics.

The association and statistical correlation of anthropogenically important trace metals (TM) Cd, Cu, Pb, Zn and degraded marine microplastic (MP) extracted from the bulk debris samples at two locations from two marine systems, estuarine and coastal, in the Croatian Adriatic coastal area were assessed. The abundance of MP particles at both sites were primarily defined by local wave climate, with the open coastal site containing 9-fold more microplastic particles (>4 mm) as compared to the semi-closed estuarine, or twice as much considering bulk plastics. Generally, the higher abundance of adsorbed metal on MP were observed in the more anthropogenically influenced estuary than in the open coastal site and followed the order: polystyrene > polypropylene > low density polyethylene. The amounts of adsorbed zinc were the highest on all types of plastics at both sites, while the affinity of polystyrene for metals followed: Zn > Pb ≈ Cu > Cd.

Assessing element distribution and speciation in a stream at abandoned Pb-Zn mining site by combining classical, in-situ DGT and modelling approaches.

The distribution and speciation of elements along a stream subjected to neutralised acid mine drainage (NAMD) effluent waters (Mátra Mountain, Hungary; Toka stream) were studied by a multi-methodological approach: dissolved and particulate fractions of elements were determined by HR-ICPMS, whereas speciation was carried out by DGT, supported by speciation modelling performed by Visual MINTEQ. Before the NAMD discharge, the Toka is considered as a pristine stream, with averages of dissolved concentrations of elements lower than world averages. A considerable increase of element concentrations caused by effluent water inflow is followed by a sharp or gradual concentration decrease. A large difference between total and dissolved concentrations was found for Fe, Al, Pb, Cu, Zn and As in effluent water and at the first downstream site, with high correlation factors between elements in particulate fraction, indicating their common behaviour, governed by the formation of ferri(hydr)oxides (co)precipitates. In-situ speciation by the DGT technique revealed that Zn, Cd, Ni, Co, Mn and U were predominantly present as a labile, potentially bioavailable fraction (>90%). The formation of strong complexes with dissolved organic matter (DOM) resulted in a relatively low DGT-labile concentration of Cu (42%), while low DGT-labile concentrations of Fe (5%) and Pb (12%) were presumably caused by their existence in colloidal (particulate) fraction which is not accessible to DGT. Except for Fe and Pb, a very good agreement between DGT-labile concentrations and those predicted by the applied speciation model was obtained, with an average correlation factor of 0.96. This study showed that the in-situ DGT technique in combination with model-predicted speciation and classical analysis of samples could provide a reasonable set of data for the assessment of the water quality status (WQS), as well as for the more general study of overall behaviour of the elements in natural waters subjected to high element loads.

A recent history of metal accumulation in the sediments of Rijeka harbor, Adriatic Sea, Croatia.

We studied metal pollution in the sediments of Rijeka harbor, including anthropogenic influence during recent decades and at the present time. Sediment profiles were collected at ten sampling points. The concentrations of 63 elements in bulk sediment were obtained using ICP-MS, and the concentrations of selected elements were evaluated by statistical factor analyses. We also calculated metal-enrichment factors and geoaccumulation indices and constructed spatial-distribution maps. Mercury (Hg) was the heaviest pollutant, with concentrations exceeding 4 mg/kg. Silver (Ag) was the second most important pollutant, with constantly increasing values. The average concentrations of the most toxic elements were comparable to those found in sediments of other ports throughout the world, and their toxicity ranged from threshold values [chromium (Cr), arsenic (As)] and midrange-effect values [cadmium (Cd), lead (Pb), copper (Cu), zinc (Zn), nickel (Ni)] to extreme-effect values (Hg). Metal pollution has decreased during recent decades, except for Ag and barium (Ba).

Establishing of monitoring network on Kosovo Rivers: preliminary measurements on the four main rivers (Drini i Bardhë, Morava e Binqës, Lepenc and Sitnica).

The main goal of this work was to suggest to authorities concerned a monitoring network on main rivers of Kosovo. We aim to suggest application of WFD (Water Framework Directive) in Kosovo as soon as possible. Our present chemical research could be the first step towards it, giving an opportunity to plan the monitoring network in which pollution locations will be highlighted. In addition to chemical, future ecological studies could be performed. Waters of the rivers Drini i Bardhë, Morava e Binçës, Lepenc and Sitnica, which are of supra-regional interest, are investigated systematically along the river course. Sediments of these rivers were also investigated at the same monitoring points and results have recently been published by us. In this paper we present results of mass concentrations of eco-toxic metals: Cu(II), Pb(II), Cd(II), Zn(II) and Mn(II) in waters of four main rivers of Kosovo, using Anodic Stripping Voltammetry (ASV), Atomic Absorption Spectrophotometry (AAS) and Ultraviolet-Visible (UV-VIS) Spectrometry. Also some physico-chemical parameters are determined: water temperature, electrical conductivity, pH, alkalinity, total hardness and temporary hardness. Results of concentrations of eco-toxic metals in water are compared with concentrations found in sediments at the same locations. Statistical methods are applied to determine anomalous regions Classification of waters at each sampling station of our work was tentatively performed based on metal indicators, using Croatian standards. Our results are showing that concentrations of Zn in all waters are low and pose no risk for living organisms. Exception is water at S5 station, where concentration is above permanent toxic level. Concentrations of Pb and Mn are high at D5 station on Drini i Bardhë River (14 km from boarder to Albania) and at all stations along Sitnica River. Cadmium in high concentrations which is above permanent toxic level is measured in water only at two stations, one (M1) on Morava e Binçës River and the other (S5) on Sitnica River (56 km from boarder to Serbia). Comparison with available results from the past shows that water pollution with respect to toxic elements decreased since 1989, what is explained with closing of heavy industry since then. Continuation of water and sediment monitoring using more than one experimental technique is highly recommended, particularly at locations S2 and S5 with anomalous concentrations of toxic elements, as well as establishing of permanent network of monitoring stations by Kosovo authorities. Remediation of sediments at polluted locations in Sitnica River would be desirable.

Levels of elements in the surficial estuarine sediments of the Hugli River, northeast India and their environmental implications.

The present paper is the first document of a detailed geochemical and mineralogical study of muddy to sandy mud estuarine sediments of the Hugli River collected from five different sites along its course in the coastal areas of West Bengal, northeast India. The present work attempts to establish the status of distribution and environmental implications of 52 elements in the surficial estuarine sediments and their possible sources of derivation. The level of both metallic and non-metallic elements shows a wide range of variation all along the course of the estuary and can be attributed to their differential derivation from the source rocks and differential discharge of untreated effluents originating from industrial, agricultural, aquacultural as well as domestic sewage. The element contents, particularly the heavy metal content in the sediments, are the lowest in the upstream part of the estuary at Diamond Harbor, whereas, these are slightly higher in the intermediate stretch of the estuary at Haldia to highest in the mouth of estuary at Gangasagar. These changes indicate that the metals that are carried from upstream find their ultimate depositional sink at the delta mouth near Gangasagar, where almost all the elements showed elevated values. The majority of the elements have their highest concentrations at Canning, a site within the tidal channel network of the Hugli-Matla drainage basin away from the direct influence of the Hugli River. This site is severely contaminated with huge organic load from domestic sewage, aquaculture, intensive trawling activities and agricultural runoff. Moreover, the site suffers from heavy siltation load causing an almost moribund condition of Matla River at this point. Equi-dimensional quartzo-feldspathic mineral grains are consistent components in the siliciclastic composition of the sediments and their sizes at each station are controlled by respective hydrodynamic conditions. Various flaky minerals (mica, chlorite, hornblende) are also present but show inconsistent patterns of distribution. These flaky minerals remain in suspension for a long time and do not follow the usual law of settling of particles depending on the hydrodynamic regime prevailing in the area. Presented data will serve as a baseline against which future anthropogenic effects may be assessed. A comprehensive account of heavy metal content in sediments from different coastal regions of peninsular India has also been presented for purpose of comparison.

A comparison of anthropogenic mercury pollution in Kastela Bay (Croatia) with pristine estuaries in Ore (Sweden) and Krka (Croatia).

Anthropogenic mercury pollution was studied in Kastela Bay (Croatia), 10 years after chloralkaline plant (PVC) stopped production. The concentration of total mercury determined in sediments which are composed mainly of calcite and quartz, are in the range 14,280-30,400 ng/g. The values are higher than reported in the literature for Elbe and Seine estuaries and also above 25,000 ng/g used for criterion in remediation project in Minamata Bay. The concentration of methylmercury 6.05-36.74 ng/g are typical for slightly to highly contaminated estuarine sediments. The low ratio of methylmercury to total mercury found in sediments of Kastela Bay is in the range 0.04-0.18%. It can be explained that in this region predominate conditions which do not promote in-situ methylation. Sediments were found to be highly anoxic. Concentrations of total mercury in unfiltered surface waters are in the range 69-145 ng/l and in unfiltered bottom waters in the range 230-1,418 ngl(-1). High concentrations found in bottom waters suggest that either resuspension or partial dissolution of sediments takes place. An experiment performed on filtered and unfiltered waters showed that about 85% of total mercury in surface water and almost 100% in bottom water was retained on 45 microm filters. To demonstrate contrasts, two pristine estuaries from norths and south Europe were studied. Silicious sediments of Ore estuary (Sweden) and calcareous sediments of Krka estuary (Croatia) have total mercury concentrations close to accepted background level. The ratio of methylmercury to total mercury is < or = 1% in all samples with one exception. The highest observed ratio (2.70%) was in the surface sediment from E2 station in Krka estuary measured in March 2000. This location is suitable for studying methylmercury formation in pristine environment.