Contamination Of Bottom Sediments Research Articles

Assessment of Water Status, Bottom Sediments, Macrophytes in the Light of Index Analysis and Geochemical Parameters of Selected Dam Reservoirs of Kielce Upland (Poland)

Concentrations of trace elements such as Cr, Zn, Cd, Co, Mn, Cu, Ni, Pb, and Fe were investigated in water, bottom sediments, and macrophytes (Phragmites australis and Typha latifolia L.) collected from the Borków, Wilków, and Rejów water reservoirs in the Kielce Upland (Poland). The main objective of this study was to investigate the condition of water, bottom sediments, and macrophytes in selected three sedimentary basins of the Kielce Upland and to identify natural and anthropogenic factors influencing this condition. The secondary objectives were (i) to determine the contents of trace metals in water, bottom sediments, and macrophytes, (ii) to assess the quality of abiotic and biotic elements of the ecosystem based on selected criteria, (iii) to compare reservoirs in terms of pollution, and (iv) to determine the ability of macrophytes to be used as a bioindicator of water/sediment pollution. Field tests were conducted in 2021. The trace metals in water were determined by ETAAS (Cr, Cd, Mn, Cu, Ni, Pb) and FAAS (Zn), and spectrophotometry method (Fe). The trace metals in sediments and macrophytes, including Cr, Zn, Cd, Co, Mn, Cu, Ni, Pb, and Fe, were detected using ICP-OES method. Contamination of bottom sediments with potentially toxic metals was determined based on the geo-accumulation index (Igeo), contamination factor (CF), and pollutant load index (PLI). Statistical analyses were performed using the Statistica PL 13.1. The analyses showed that the accumulation of trace elements in the surface layer of the reservoir sediments increases as follows: in Borków, Cd < Co < Ni < Cu < Pb < Cr < Zn < Mn < Fe; in Wilków, Cd < Co < Cu < Ni < Pb < Cr < Zn < Mn < Fe; and in Rejow, Cd < Co = Cu = Ni = Pb < Zn < Cr < Mn < Fe. It was shown that the average distribution of metals in the bottom sediments of the studied reservoirs was as follows: Borków > Wilków > Rejów. Research has shown that the degree of trace metal accumulation increases as follows: water < sediments < macrophytes (except Pb from the reservoir in Borków).

Biodegradation of <i>n</i>-Alkanes in Oil-Contaminated Bottom Sediments under Bioelectrochemical Stimulation

Degradation of oil hydrocarbons artificially introduced into bottom sediments in a bioelectrochemical system of a membrane-free (silt) type was studied. Passive bioelectrochemical stimulation by means of electrodes connected by an external circuit with a resistance of 1 kΩ, with an average electric current of ~85 µA was found to cause an increase in degradation during two months from 23.0 to 57.9%. Contamination of bottom sediments with oil (1.32 g/kg) slightly decreased the current in the external circuit of the bioelectrochemical system. The relationship was revealed between the degree of oil degradation and predominant utilization of the lighter n-alkanes in the C14H30–C30H62 series, compared with both the original oil and the residual hydrocarbons of the control. An increase in the representation of the alkB alkane monooxygenase genes relative to the 16S rRNA gene in the total DNA isolated from the sediments was induced by the introduction of hexadecane, both in the case of electrochemical stimulation and in the control. The results may be of interest for the development of new methods of bioelectrochemical removal of organic pollutants from anaerobic environments.

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.

Environmental and Geochemical Assessment of Bottom Sediment Pollution (Approaches, Monitoring, Utilization)

The results of ecological and geochemical assessment of the state of bottom sediments of small rivers in the city of Berezniki (Perm region) are presented, and the issues of environmental monitoring of small rivers of Verkhnekamie are identified. A comprehensive assessment of bottom sediment contamination is carried out. Their unsatisfactory condition in terms of the heavy metals content (Ni, Cu, Zn, Pb, Cd, Hg) and As was noted. Possible environmental actions for the disposal of such sediments are analyzed. It is concluded that it is advisable to carry out on-site remediation or dispose of sediments at specialized landfills followed by recycling.

ФОРМИРОВАНИЕ ХИМИЧЕСКОГО СОСТАВА ВОД СЕВЕРНОГО БАЙКАЛА В ЗОНЕ СМЕШЕНИЯ С ВОДАМИ ПРИТОКОВ

The results of studying the chemical composition of water in Northern Baikal and in the rivers flowing into it are analyzed. It is shown that the influence of river water on forming the chemical composition of water in this part of the lake is observed at the distance of 1-3 km from the cofferdam separating the Upper Angara delta from Lake Baikal. In spring and early summer, the expansion of river water in the lake is constrained by a thermal bar. In summer, a biological barrier is formed in the mixing zone, where the minimum biogenic element concentrations of and maximum phytoplankton concentrations are registered. The increased concentrations of phosphorus have been revealed in the shallow area in winter, which points to the contamination of bottom sediments and secondary pollution of water. The increased content of phosphorus in the water may be a sign of the eutrophication of Northern Baikal.

Content of heavy metals in bottom sediments of drained Kakhovka Reservoir

The article highlights the ecological danger of the destruction of the Kakhovka HPP dam and the draining of the Kakhovka Reservoir. The results of experimental studies of the content of mobile compounds and gross forms of heavy metals in five samples of bottom sediments taken from the bottom of drained reservoirs taken on the territory of the Kushugum community of the Zaporizhia district of the Zaporizhia region. Two samples were taken from the bottom of the former flood zone (Balabyne village), 2 samples — from the bottom of the former limestone quarry, which was connected to the floodplain of the Dnipro (Kushugum village) and 1 sample taken from the open area of the Kakhovka Reservoir (Malokaterynivka village). Based on the results of the research, it was established that the maximum permissible limit (for soil) of mobile compounds of lead (from 2.0 to 4.1 times), zinc (from 2.4 to 5.4 times), cadmium (from 1.9 to 2.5 times) was exceeded. and nickel (from 1.04 to 2.2 times) in all investigated bottom sediment samples. Exceeding the MPC (soil) for the content of gross forms of lead was found in five bottom sediment samples (from 1.1 to 1.5 times). Exceedings of the MPC of the soil by the content of gross forms of cadmium and manganese and mobile compounds of copper, nickel, cobalt and manganese were not detected. The maximum limit for the content of mobile compounds of iron and gross forms of zinc, copper, nickel, cobalt and iron is not regulated. The highest degree of contamination of bottom sediments by the content of: mobile compounds and gross forms of lead and nickel was found in samples taken from the bottom of a former limestone quarry (Kushugum village, Zaporizhzhia region); zinc — in a sample taken from the bottom of the former flood zone in the territory of the town of Balabyne and a sample taken from the open area of the Kakhovka Reservoir in the territory of the town of Malokaterynivka; cadmium — in the samples taken from the bottom of the former limestone quarry in the territory of the town of Balabyne and the sample taken from the open area of the Kakhovka Reservoir in the territory of the town of Malokaterynivka. According to the results of the correlation analysis, an extremely strong dependence was established between the content of mobile compounds of heavy metals and their gross forms — for cobalt (r=0.96), cadmium (r=0.92), nickel (r=0.91), lead (r=0.88) and zinc (r=0.84).

Joint research in the Baltic Sea by the Atlantic Branch of the VNIRO and the Atlantic Branch of the Shirshov Institute of Oceanology of the RAS

The aim: complex study of the Baltic Sea ecosystem, including the habitat conditions of aquatic biological resources based on the results of joint research by AtlantNIRO and the P.P. Shirshov Institute of Oceanology RAS (Atlantic Branch). Methods used: analysis of long-term data of joint expeditionary research in the open part and coastal zone of the Baltic Sea.Results: owing to the interaction of AtlantNIRO with AB IO RAS in 2018–2022, the continuity of long-term observations has been preserved and the volume of scientific information necessary for assessing the state of the habitat of aquatic biological resources in the Russian sectors of the Baltic Sea has been increased. Modern data on eutrophication and pollution, on distribution of phytoplankton, zooplankton, benthos, as well as the early ontogenetic stages of the main commercial fish have been obtained. The spatial distribution of plankton and benthic communities, including areas favorable for spawning and feeding of fish, has been detailed. A rather high contamination of bottom sediments with radionuclides in certain areas of the Baltic Sea, primarily in the Gulf of Finland, has been found.Practical significance: the implementation of the areas provided by the Agreement between Rosrybolovstvo and RAS, and above all, the participation of AtlantNIRO scientific groups in expeditions in the Baltic Sea in 2018–2022, was a significant addition to the annual research and state monitoring of aquatic biological resources and their habitats conducted by VNIRO in the Baltic Sea.

СОДЕРЖАНИЕ И РАСПРЕДЕЛЕНИЕ ТЯЖЁЛЫХ МЕТАЛЛОВ В ДОННЫХ ОТЛОЖЕНИЯХ ПЛЁСОВ ИВАНЬКОВСКОГО ВОДОХРАНИЛИЩА

Currently, the state of water bodies under the influence of technogenic factors is changing, as a rule, for the worse. Studies of the sediments of reservoirs make it possible to identify unfavorable areas and determine the sources of pollution. From the point of view of technogenic pressure, the most dangerous pollutants are trace elements Hg, Cd, Zn, Pb, Cu, Cr, Co, Ni, Fe, Mn, As. The paper presents an assessment of sediments in various areas of the Ivan’kovo reservoir. The content of mobile forms of existence of the following microelements was determined: Cd, Cu, Pb, Zn, Cr, Ni and As. The results of studies of the contamination of bottom sediments by the total concentrations of mobile forms of microelements, estimated by geo-classes - by the contamination of the sorbing fraction (less than 0.02 mm) are presented. The main contaminants are cadmium and lead, which are estimated to be slightly to moderately polluted. A picture is presented of both contamination of the bottom sediments of the Ivan’kovo reservoir with microelements, and the distribution and correlation of their mobile forms of existence in the desired sediments. From the data obtained, it can be concluded that, despite a significant number of pollution sources, at present there is no need to talk about a dangerous load on the studied objects.

Geochemistry indices and biotests as useful tools in the assessment of the degree of sediment contamination by metals

Ecological and geochemical indicators have been widely accepted as tools with the potential for rapid risk assessment of metal contamination of bottom sediments. In this study, we propose a selection of such indicators to characterize the potential ecological risks stemming from metal contamination of the bottom sediments of the Chechło reservoir (S Poland). The Chechło reservoir is located in an area formerly occupied by zinc and lead ore mining and processing industry. High amounts of metals, especially zinc (39.37–4772.00 mg/kg d.m.), cadmium (0.37–21.13 mg/kg d.m.) and lead (4.50–434.49 mg/kg d.m.) have been found in the bottom sediments. Both geochemical (CD – contamination degree) and ecological indices (mean PECQ) were indicative of bottom sediment contamination and their potential toxicity to living organisms. Most of the bottom sediment samples (71%) examined were toxic for Heterocypris incongruens, while only 9% of the samples were toxic to Sinapis alba. However, no significant correlations between the metal content and the response of the test organisms were observed. Correlation and principal component analyses (PCA) showed that silt and clay fractions were the key factors influencing the metal content in the sediments. Our study makes a contribution to building evidence of the need to integrate several indices for the assessment of environmental risks related to the presence of metals in bottom sediments rather than relying on a single one.

Assessment of the State of Water, Soil and Bottom Sediments of the Territory Adjacent to the Former Ash-disposal Area

A comprehensive chemicalanalytical investigation of the state of water, soil, bottom sediments, as well as technogenic soils of the former ash-disposal area in the water-shed area of the Red River in Khabarovsk was carried out. River water exceeds the MAC of soluble chemicals in terms of the content of suspended solids, phenols, oil products, as well as some heavy metals (iron, manganese, copper, nickel and zinc). Widespread contamination of bottom sediments and soil of the ash-disposal area with arsenic was revealed. The background rate of oil products was exceeded by 5.6 times in the soil of the water protection zone of the river. The conclusion was made about the genetic similarity in bottom sediments and soils which is due to the long-term impact of a complex of anthropogenic factors on the water-shed area of the Red River.

ACTIVITY CONCENTRATION OF RADIONUCLIDE AND EXTERNAL DOSE RATE IN BOTTOM DEPOSITS OF BRIT LAKE IN THE CHОRNOBYL EXCLUSION ZONE

The profiles of the vertical distribution of the gamma dose rate and activity concentrations of 90Sr, 137Cs, 154Eu, and 241Am in the bottom sediments of Brit Lake were obtained. The lake is located within the dammed section of the Krasnenska floodplain of the Pripyat River in the Chоrnobyl Exclusion Zone (51.44844°; 30.06020°). The values of the dose rate and activity concentration of 137Cs in the sediments reached 23 μGy h−1 and 43 Bq∙cm−3. In the lake Brit radioactive contamination of bottom sediments did not depend on the depth of the lake due to the washing of radionuclides from the water intake. A weak correlation was observed between values of in-situ measured and calculated gamma dose rates in bottom sediments. The average calculated and measured dose rates of gamma radiation in bottom sediments of the lake varied within the range of 1.3-19 μGy h−1 and was compatible with the internal radiation dose to fish (5-15 μGy h−1). Contribution of radionuclide content in water to the gamma dose rate does not exceed 2 nGy h−1. In October 2021, appropriate equipment for acoustic 3-D telemetry and individual dosimetry of various fish species was installed in the lake to reduce uncertainty in estimates of doses of external exposure to aboriginal fish in the lakes

Application of magnetic sorbents modified with molecular imprinted polymers for screening of phenolic xenoestrogens

A new method for the determining phenolic xenoestrogens, chemicals that destroy the endocrine system (EDC), i.e., 4-octylphenol (OP), 4-nonylphenol (NLP) and bisphenol A (BPA), in sediments and river waters with preliminary concentration on magnetic sorbents functionalized by polymers based on molecular imprints is proposed. were determined In the concentrates EDC were converted to derivatives by reaction with acetic anhydride and then determined by gas chromatography in combination with mass spectrometry (GC-MS). The accuracy of the determination was evaluated by the "added–found" method. Use of the molecular imprinted polymers allows determining up to 5 ng/l NLP and 6 ng/l OP and BFA in wastewaters. In bottom sediments, the limit of determination was 100 ng/kg for NLP and 150 ng/kg for OP or BPA. The decrease in sensitivity was due to the high contamination of bottom sediments and increased matrix effects. Products of degradation of humic acid, surfactants and petroleum products have the greatest interfering effect. The method was tested on EDC screening in waters and bottom sediments of the Voronezh reservoir. Sites near the unorganized discharge of wastewaters and near the discharge of municipal wastewater treatment plants were selected as sampling points. The maximum concentrations of OP, NLP and BPA found in the river waters were 335, 1138 and 144 ng/l, respectively, and in the bottom sediments were 6.9, 10.7 and 5.9 μg/kg, respectively.

Metal contamination in sediments of dam reservoirs: A multi-facetted generic risk assessment

The quality of bottom sediments is a key factor for many functions of dam reservoirs, which include water supply, flood control and recreation. The aim of the study was to combine different pollution indices in a critical generic risk assessment of metal contamination of bottom sediments. Both geochemical and ecological indices reflected that sediment contamination was dominated by Zn, Pb and Cd. The ecological risk indices suggested a high riks for all three metals, whereas human health risks were high for Pb and Cd. An occasional local contamination of sediments with Cr and Ni was revealed, although at levels not expected to cause concerns about potential ecological or health risk. Sediments from the Rybnik reservoir for Cu only revealed a high potential ecological risk. EF turned to be as being the most useful, whereas TRI (∑TRI) was the most important ecological index. All multi-element indices suggested similar trends, indicating that Zn, Pb and Cd taken altogether had the greatest impact on the level of sediment contamination and posed the greatest potential ecological and health risks to organisms. The use of sequential BCR extraction and ecotoxicity analyses allowed for a multi-facetted generic risk assessment of metals in sediments of dam reservoirs.

Distribution and classification of macrozoobenthos in Peter the Great Bay of Japan Sea in relation to contamination of bottom sediments

Distribution of 211 species and larger taxa of benthic animals is considered along the gradient of chemical contamination in bottom sediments (by TPF index) on the data of long-term observations (1992–2019), using hierarchical Hausman-Olf-Fresco logistic regression models. Frequency of occurrence and density in settlements are used as the quantitative measures of the macrozoobenthos distribution. Parameters of the species relation to contamination are determined, as mean coordinate of the response curves, position of the optimum, and width of the outer and central niches. By these parameters, using the fuzzy sets algorithm, the taxa are classified to five groups: i) extremely sensitive; ii) highly sensitive; iii) moderately tolerant; iv) tolerant; and v) extremely tolerant to pollution (ES, S, MT, T and ET, respectively). Both stenobionts, steno-eurybionts and eurybionts are presented in each group, but the stenobionts dominate in ES and S groups and the eurybionts prevail in T and ET groups, being the opportunists of the II and I order, while the taxa of different biontity are equally presented in MT group. The classification could be used for interpretation of changes in composition and structure of macrozoobenthos in the areas subjected to anthropogenic pollution.

Sydney Harbour: Seiches, tides and mean circulation

Beginning with observations from 1901, sea level elevations and currents from Sydney Harbour are examined across a broad frequency range. The mean currents, annual components of sea level, tides and seiches, mainly in the South Arm, are the focus. Tidal and mean currents are ~0.01 m s-1. The general circulation is estuarine-like with a thin, near-surface outflow layer and a thicker, deeper inflow. The distribution of contaminants in bottom sediments suggests the circulation, though weak, plays a retentive role in the Arm, transporting sediments towards its head. Analysis of 11-years of sea level data indicates a strong annual cycle, more energetic during winter than from late spring to early fall. The increased energy occurred at all frequencies except for tides. Seiches, with periods of ~0.5 to 2 h, emerge as a strong contributor to sea level and currents. The distributions of elevation and flow amplitudes associated with seiches were derived. With maximum observed values of 0.74 m and 0.24 m s-1, seiche displacements and currents can exceed those associated with tides and the mean circulation. While earlier studies identified only the dominant fundamental seiche mode, recent sea level data sampled at 1-minute show that modes 2-4 occur. Keywords: Sydney Harbour, sea level, mean circulation, tides, seiches

Impact of dredging on the environmental state of a small river with considering the composition of bottom sediments

Reports on the environmental impact assessment of planned activities aimed at restoring the hydrological regime and sanitation of rivers do not always pay attention to in-depth analysis of the physicochemical composition of bottom sediments. The silt deposits have proven to be a good ameliorant for agricultural lands, provided they are of satisfactory quality. Bottom sediments, especially their fine alluvial fraction, accumulate various compounds and trace elements, including heavy metals. Analysis of the content of iron Fe, manganese Mn, cobalt Co, chromium Cr and determination of the integrated level of contamination of bottom sediments did not reveal their toxic contamination in the area of the village Kleshnivka and the village Petrykivka. Determination of "geoaccumulation indices" by G.M. Mueller allowed to classify the sediments of the Chaplinka River as unpolluted, and the man-caused load on the hydroecosystem as low. In compliance with the recommendations on the content of Mn grades in the soil cover of the obtained fifth Igeoclass, which provides heavy pollution and significant man-caused load on the hydroecosystem. To characterize the processes occurring in the hydroecosystem of the Chaplynka River, the bottom accumulation coefficient was calculated. The assessment of the ecological status of hydroecosystems revealed an overwhelming ecological emergency. There is a significant threat of deposits of iron Fe, manganese Mn in bottom sediments. Despite the low risk of contamination of bottom sediments with chromium Cr, the risk will increase due to the rather variable chemical composition of surface waters, and hence the possibility of an ecological crisis for the hydroecosystem. The sanitary condition of a small river could be improved by restoring its hydrological regime. The decrease in the efficiency of dredging works is related to the regulation of the regulation of the riverbed. In the vast majority of cases, hydraulic structures are not provided for or do not correspond to the current level regime of watercourses. After clearing the river bed, there is a danger of their secondary silting, due to the abandonment of part of the temporary dumps on the banks within the water protection zones without fixing.

The study on contamination of bottom sediments from the Odra River estuary (SW Baltic Sea) by tributyltin using environmetric methods

We present the first comprehensive study on the occurrence of tributyltin (TBT) in the Odra River estuary (SW Baltic Sea) that encompasses both densely populated and urbanized agglomeration Szczecin city, and sparsely populated biosphere reserves “Natura 2000”. Relationship between TBT and physicochemical parameters of bottom sediments such as granulometry total organic carbon (TOC), total nitrogen (TN), acid volatile sulfide (AVS), As, and metals: Ba, Cd, Co, Cr, Cu, Fe, Hg, Ni, Mn, Mo, Pb, Sn, and Zn was investigated in 120 samples collected in 2017 and 2018. The highest TBT concentrations were over 3000 ng g−1 (dry weight). They were observed in samples collected in the vicinity of the ship maintenance zones of the Szczecin city. Despite the EU ban on its use since 2003, TBT is still present in the environment. Environmetrics analyses such as correlation, cluster, and principal component analysis of obtained results revealed that the main source of sediments contamination by TBT, metalloids, and metals is likely related to the maritime industry: shipyards, ship maintenance as well as ports and marines. TBT is still present in the bottom sediments because of its emission to the environment with dust and paint chips formed during sandblasting cleaning of ship surfaces. The pollutant is further transported with water current to remote localization in the Szczecin Lagoon. Slow water exchange between the Szczecin Lagoon and the Baltic Sea favors accumulation of pollutants in the lagoon sediments. Therefore, it is necessary to implement environmentally friendly methods into ship maintenance and management of the materials from dredged waterways, harbors, and marinas.

Accumulation of Heavy Metals in Dam Sediments Effects on Plankton Productivities of the Arabian Gulf

Purpose: Metal accumulation in sediments threatens adjacent ecosystems due to the potential of metal mobilization and the subsequent uptake into food webs. Dams produce important changes in flow regime and sediment deposition. When inundation starts with the building of dams, water surface area increases, flow rate decreases, and sediment carried by the valleys is deposited in the dams. However, there is a lack of research on the chemical properties of deposited sediment in dams. Method: We aimed to fill this gap in the literature by providing valuable data on the particle size and heavy metal of sediment in different dams. Therefore, the aim of this study conducted within the Northern emirates of United Arab Emirates dams, to estimate heavy metal concentration of sediment, including particle size distribution. A total of eight sediment samples from each dams were collected and analyzed for heavy metals. The concentrations of Iron (Fe), Nickle (Ni), Copper (Cu), Zinc (Zn), Lead (Pb), Cadmium (Cd), Chromium (Cr), and Cobalt (Co) in sediment samples were determined using Atomic Absorption Spectrophotometer (AAS). Results: The concentrations of the heavy metals studied in the sediment samples were accumulated as Fe> Ni> Cr> Zn> Co> Pb> Cu. The concentrations of Ni and Cr have exceeded the threshold in the sediments of in line with W.H.O standards. Cadmium was not detected in soil, while other elements detected were in trace amount below the allowable limits in soil. The consideration of environmental factors is required to develop pollution managements and assess environmental risks for dam sediments. Conclusion: The studies conducted provide background to a discussion on the extent of anthropogenic pressure on the natural environment in the Arabian Gulf, further underlining the relationship between retention of sediments in the dam and the increase in heavy metal contamination of bottom sediments and to the marine environment which effects possible to plankton productivity.

Some Problems of Oil Contamination of Bottom Sediments in Aquatic Ecosystems (a Review)

Some Problems of Oil Contamination of Bottom Sediments in Aquatic Ecosystems (a Review)

Trace Metal Contamination of Bottom Sediments: A Review of Assessment Measures and Geochemical Background Determination Methods

This paper provides an overview of different methods of assessing the trace metal (TM) contamination status of sediments affected by anthropogenic interference. The geochemical background determination methods are also described. A total of 25 papers covering rivers, lakes, and retention tanks sediments in areas subjected to anthropogenic pressure from the last three years (2019, 2020, and 2021) were analysed to support our examination of the assessment measures. Geochemical and ecotoxicological classifications are presented that may prove useful for sediment evaluation. Among the geochemical indices, several individual pollution indices (CF, Igeo, EF, Pi (SPI), PTT), complex pollution indices (PLI, Cdeg, mCdeg, Pisum, PIAvg, PIaAvg, PIN, PIProd, PIapProd, PIvectorM, PINemerow, IntPI, MPI), and geochemical classifications are compared. The ecotoxicological assessment includes an overview of Sediment Quality Guidelines (SQG) and classifications introduced nationally (as LAWA or modified LAWA). The ecotoxicological indices presented in this review cover individual (ERi) and complex indices (CSI, SPI, RAC, PERI, MERMQ). Biomonitoring of contaminated sites based on plant bioindicators is extensively explored as an indirect method for evaluating pollution sites. The most commonly used indices in the reviewed papers were Igeo, EF, and CF. Many authors referred to ecotoxicological assessment via SQG. Moreover, PERI, which includes the toxic response index, was just as popular. The most recognised bioindicators include the Phragmites and Salix species. Phragmites can be considered for Fe, Cu, Cd, and Ni bioindication in sites, while Salix hybrid cultivars such as Klara may be considered for phytostabilisation and rhizofiltration due to higher Cu, Zn, and Ni accumulation in roots. Vetiveria zizanoides demonstrated resistance to As stress and feasibility for the remediation of As. Moreover, bioindicators offer a feasible tool for recovering valuable elements for the development of a circular economy (e.g., rare earth elements).