Микроэлементный состав донных отложений водных объектов в условиях городской застройки

Heavy metal pollution in lakes is an issue that endangers ecosystems worldwide; however, the vertical properties of heavy metals in the water columns and sediment cores of lakes have been rarely evaluated simultaneously. This study revealed the pollution, risks, and sources of heavy metals from surface water to deep sediments in four typical shallow lakes located in central China. The results showed that the concentrations of heavy metals, except Hg, had insignificant stratification in the water column. Heavy metals had three vertical profiles in sediment cores, i.e., the concentrations of As, Hg, Cd, Pb, and Mn in the surface sediment (0-9 cm) were higher than that in the bottom sediment (9-45 cm) (p < 0.05), the concentrations of Cr, Co, Fe, and Ni in the bottom sediment were higher than the surface sediment (p < 0.05), and the concentrations of Cu and Zn had no significant stratification. The Nemerow pollution index showed that heavy metal pollution dominated by Hg reached slight-moderate levels, and had higher levels in surface water than that in bottom water (p < 0.05). The Nemerow integrated risk index showed that the heavy metals had moderate-extreme potential ecological risks (Cd contributed 43.4%) in the sediments, and the ecological risk in surface sediment was significantly higher than that in bottom sediment (p < 0.01). Principal component analysis revealed that agriculture, transportation, and chemical industry were the major sources of heavy metals in water and surface sediments, while agriculture and steel-making were the primary sources in bottom sediments. This study provides valuable data and insight for the control of heavy metal pollution in lakes with high human activity loads.

The change in the qualities of water and bottom sediment accompanied with the development of anoxic layer was studied. A dredged water region in the South part of Lake Biwa was being used as a model of the Northern Lake with a fair water depth. An anoxic layer was observed after the development of the water stratification due to vertical difference in temperature in June. The accumulation of ammonia, phosphates, iron, manganese, and sulfides was observed in the hypolimnion. As a result, considerable amount of these chemical components was found to liberate from bottom sediment into the bottom water. Active liberation of sulfides began not after the development of an anoxic layer but at almost the same time as the stratification. Sulfide production in the bottom sediment with a large amount of organic matter accumulation was accelerated by the presence of organic acids such as formic, butyric, and lactic acids. The production of these acids in the bottom sediment was closely related with the supply of dissolved oxygen to the bottom surface, which might be governed by the vertical diffusion of lake water.

The purpose of this study is to investigate the relationship between water quality of river with heavy metal and sediment content in Sungai Kenau at Pahang using new developed model named WQ-HeMeS. Through this study, water quality has been analysed by using Water Quality Index (WQI) & National Water Quality Standard for Malaysia (NWQS). Water quality of river in Sungai Kenau have been observed by several test which are Dissolve Oxygen, Biochemical Oxygen Demand, Chemical Oxygen Demand, Ammoniacal Nitrogen, Total Suspended Solid, Phosphorus and Nitrogen as Nitrate. Meanwhile, the sedimentation rate was determine using Schoklistch method and Duboy method. There are 2 condition for heavy metal considered in the analysis which are heavy metal in water and heavy metal in sediment. Heavy metal in water was tested using laboratory tools named as Atomic Absorption Spectroscopy (AAS) while heavy metal in sediment have been determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The classification of heavy metal in water have been done based on NWQS meanwhile heavy metal in sediment were observed based on Index of Geo-Accumulation and Metal Contamination Factor. After collecting all result from lab testing, the the relationship of water quality, sedimentation rate and heavy metal rate both in water and sediment was determine using generated model. Based on Malaysia WQI Standard, the result shown that water in Sungai Kenau is classified as Class I which means as for water supply, there are no treatment is necessary.

Стаття містить результати моніторингових досліджень, спрямованих на встановлення фонових показників (базового стану) якості поверхневих і підземних вод Південної ділянки Балахівського родовища графіту. Натурні вишукування передбачали відбір зразків води з колодязів і поверхневих водотоків і водойм. Актуальність проведених досліджень полягає в необхідності встановлення фонових значень основних показників хімічного складу природних вод на території потенційного впливу гірничих підприємств. З отриманих результатів проб води можна констатувати, що якість води загалом гірша в досліджених свердловинах в селі Олександрівка, селі Пустельникове, селищі міського типу Балахівка та селі Новий Стародуб, ніж у річці Інгулець і річці Вівнянка й навіть у більшості водойм – як у кар’єрних озерах, так і у ставках-запрудах. Зафіксовано перевищення гранично допустимих концентрацій у поверхневих і підземних водах за такими інгредієнтами: Ca, Mg, SO4, Na, K і Mn. Оцінка якості показала, що обстежені природні води за блоком загальносанітарних показників можна схарактеризувати як «добрі», чисті води прийнятної якості. Встановлена подібність досліджених вод за катіонним складом, натомість в аніонному складі є відмінності: у поверхневих водах переважає сульфат-іон, у підземних водах – гідрокарбонат. Для еколого-геохімічної оцінки якості досліджених підземних вод було застосовано критерій біологічно значущої концентрації (БЗК). Мікроелементний аналіз показав нестачу в підземних водах таких мікроелементів: V, Cr, Co, Ni, Cu, Zn, Cd та Pb. Проведені гідрохімічні дослідження дали змогу встановити фонові показники базового стану якості довкілля обстеженої території. Надалі необхідно проводити моніторингові спостереження за змінами хімічного складу поверхневих і підземних вод Південної ділянки Балахівського родовища графіту під час роботи гірничо-видобувного підприємства.

The composition of heavy metals in water and surface soils of iron ore mining sites were investigated to evaluate on the potential occurrence of heavy metal contamination. Physico-chemical characteristics of the waters were also investigated to determine the current status of water quality index (WQI) of the sites. Samples of water and surface soils of active mine (Kuala Lipis) and abandoned mine (Bukit Ibam) in Pahang were collected at four locations, respectively. The physico-chemical parameters measured for WQI were pH, dissolved oxygen, biological oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS), and ammoniacal nitrogen (AN). The water quality parameters were classified according to the Department of Environment (DOE) water quality classification. The study revealed that most of the sites in Bukit Ibam and Kuala Lipis were categorized as clean to slightly polluted. On the other hand, heavy metal analysis in water showed that aluminium and manganese level in both sites have exceeded the allowable limits for raw and treated water standards by the Ministry of Health. For heavy metal compositions in soils showed most of the heavy metal concentrations were below the recommended guideline values except for lead, arsenic, zinc and copper.

Spatial distribution of akinetes of Anabaena flos-aquae (cyanobacteria) in littoral bottom sediments of a small Siberian reservoir was studied. Akinete abundance in bottom sediments is found to be related with type of sediments and presence of higher water plants. The highest abundance of akinetes was observed in silty sediments at stations located in higher plants bed (mainly emerged plants Typha latifolia L. and Phragmites australis (Cav.) Trin. ex Steud.). These results demonstrate that macrophyte beds could increase the size of the potential cyanobacterial inoculum by accumulation of akinetes in shallow bottom sediments and, as a result, favour cyanobacterial bloom development. In addition, seasonal dynamics of Anabaena flos-aquae, including vegetative cells and akinetes, in bottom sediments and water column in open water and littoral of the reservoir was studied. Dynamics of Anabaena abundance in the water column at the central station and littoral stations were very similar, but the number of cells in the littoral achieved higher year maximum than that at the central station. The highest seasonal peak of vegetative cells and akinetes in the water column was observed at the littoral station, located in emerged higher plants bed. However, at this part of the reservoir lowest intensity of akinete production was recorded. Deposition of akinetes to bottom sediments occurred both in open water and littoral. Nevertheless, seasonal dynamics of akinetes in bottom sediments differed between these sites. At the central station accumulation of akinetes in bottom sediments occurred throughout the summer, but in the littoral abundance of akinetes decreased just after their sedimentation. Hence, abundance of akinetes in the littoral sediments of the reservoir is markedly lower than that in the deeper central part.

Mercury deposition and methylmercury formation in Narraguinnep Reservoir, southwestern Colorado, USA

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Integrated water quality management

A method of GIS mapping was developed to identify and assess the contributions of sources of matter to the composition of surface waters. The basis for the creation of the GIS database was the results of the study of the spatial diversity of the chemical composition of surface waters. Geoinformation analysis included the creation of a digital framework for mapping, vectorization of mapping sources and Earth remote sensing materials, creation of a single database combining cartographic, statistical information and field observation materials, morphometric relief analysis based on a digital relief model, creating a landscape basis for base maps, creating thematic maps, analyzing changes in the components of geosystems, creating electronic cartographic layers allowing to identify participation of solute sources in formation of water composition. The analysis of component changes was based on the results of different-time studies of the composition of water and bottom sediments. Based on the comparison of the chemical composition of the waters of the Baikal tributaries with the chemical and mineralogical composition of rocks, an approach was developed to identify sources of solute and assess their contributions to the formation of macro- and microelement compositions of surface waters. To solve the problems of the study, methods of statistical analysis of data, multicomponent mixing using systems of linear equations, field methods of data collection were used. Three main categories of solute sources (silicate, sulfide-containing silicate, carbonate rocks) were identified and their contributions to the chemical composition of water were calculated. On the basis of microelement tracers, the contributions of silicate rocks were divided into contributions of primary and secondary silicate rocks, ore-containing silicate rocks without sulfides were isolated. By comparing the ratios of concentrations of trace elements in the waters of uncontaminated territories and wastewater of enterprises, tracers were identified that made it possible to identify sources of surface water pollution. Maps of territories that determine a certain chemical composition of surface waters were compiled, which was first classified on the basis of the ratio of the contributions of drained rocks.

To understand aquatic environmental deterioration due to the anoxic state in an organically polluted water body, water quality dynamics under anaerobic conditions were examined through beaker-scale water quality monitoring. This study focused on the dynamic properties of NO3–N, NH4–N, PO4–P, and sulfide from the biochemical reactions point of view, and based on anaerobic respiration activities, such as denitrification, iron reduction, and sulfate reduction. The specific aims of this study were to quantitatively estimate the impacts of the oxidative/reductive state of the sediment surface and the high/low concentrations of dissolved organic matter on the dynamic properties of water quality under anaerobic conditions. The beaker-scale water quality monitoring was carried out through continuous measurements of dissolved oxygen and oxidation–reduction potential (ORP), as well as periodic observations of water quality parameters for six cases that are composed from combinations of three experimental conditions: (1) concentration of dissolved organic carbon (DOC); (2) redox state of the sediment; and (3) concentration of NO3–N. As a result, the temporal changes in ORP under anaerobic conditions exhibited a five-step process of decline without these conditions. Also, high DOC concentrations and oxidative states of the bottom mud accelerated the release of PO4–P and sulfide generation through promoting biological iron reduction and sulfate reduction, because these conditions increase respiratory substrates for anaerobic microorganisms, such as iron and sulfate-reducing bacteria. It was concluded that our results would provide important information about the mechanisms of aqueous environmental deterioration due to organic pollution in closed water bodies.

A method is proposed for determining the mass of oil pollution per unit area of bottom sediments of water bodies, which makes it possible to associate pollution not only with the concentration of pollutants, but also with the area of the reservoir. The approach relates to the field of environmental protection, in particular to the analytical control of the content of oil pollution in mineral, organogenic and mixed bottom sediments. It can be used for environmental monitoring of polluted water bodies, for assessing the damage caused to a water body, and for planning treatment works. The method for determining the mass of oil pollution per unit area of bottom sediments of water bodies includes sampling, drying the sample to an air-dry state, extraction of oil products from bottom sediments, chromatographic separation of oil products from associated organic compounds of other classes, quantitative determination of oil products by absorption intensity in the infrared spectrum. A survey of 88 oil-contaminated reservoirs within the Samotlor oil field in the north of Russia was carried out, in which the proposed method was tested.

Belgorod Oblast has limited water resources. The paper explores the chemical and ecological characteristics of water and bottom sediments in the Oskol River tributaries. In samples of water taken from small rivers, Maximum Allowable Concentrations (MAC) for pollutants was excessive, including suspended matter, ammonium ions, nitrite ions, phosphate ions, BOD5 and mineral elements. A hydrochemical water pollution index (WPI6) ranges from 1.0 to 1.9, which characterizes water bodies in the categories from clean to moderately polluted watercourses. A comparatively high WPI6 index is recorded in summer for the Kotel River – 1.4, for the Belenkaya River – 2.3, which is attributed to a high concentration of ammonium ions, nitrites and phosphates found to be present in the water. This indicates recent pollution and a changing trophic status of the reservoir. The amount of metals in river water exceeds the MAC norms: for iron – 1.7 -6 MAC; for copper – 1.6 - 8 MAC; for manganese – 0.8 - 22 MAC; for zinc – 1.9 - 9.9 MAC. Concentrations of micronutrients are subject to significant seasonal fluctuations. No excess of lead is found to be present in surface waters. In the samples of bottom sediments taken from the Oskol River tributaries, no excess of MAC values is found, except for lead (1.1 - 2.9 MAC), manganese (1.6 - 2.2 MAC), copper (1.2 - 1.6 MAC) and phosphate ions (1.3 - 2.3 MAC). It is obvious that the sources of pollution for small rivers are runoffs from agricultural land, livestock farms and household wastewater of nearby settlements.

Hyperspectral spectrum enables assessment of heavy metal content, but research on low concentration in water is limited. This study employed in situ hyperspectral data from Dalian Lake, Shanghai to develop a machine learning model for accurately determining heavy metal concentrations. Initially, we employed a combination of empirical analysis and algorithm-based analysis to identify the optimal features for retrieving Cu and Fe ions. Based on the correlation coefficients between heavy metals and water quality, the feature bands for TOC, Chl-a and TP were selected as empirical features. Algorithm-based feature selection was conducted by employing the random forest (RF) approach with the original spectrum (OR), first-order derivative reflectance (FDR), and second-order derivative reflectance (SDR). For the development of a prediction model, we utilized the Genetic Algorithm-Partial Least Squares Regression (GA-PLSR) approach for Cu and Fe ions inversion. Our findings demonstrated that the integration of both empirical features and algorithm-selected features resulted in superior performance compared to using algorithm-selected features alone. Importantly, the crucial wavelength data primarily located at 497, 665, 686, 831 and 935 nm showed superior results for Cu retrieval, while wavelengths of 700, 746, 801, 948, and 993 nm demonstrated better results for Fe retrieval. These results also displayed that the GA-PLSR model outperformed both the PLSR and RF models, exhibiting an R2 of 0.75, RMSE of 0.004, and MRE of 0.382 for Cu inversion. For Fe inversion, the GA-PLSR model outperformed other models with an R2 of 0.73, RMSE of 0.036, and MRE of 0.464. This research provides a scientific basis and data support for monitoring low concentrations of heavy metals in water bodies using hyperspectral remote sensing techniques.

Concentrations of heavy metals (Cu, Fe, Zn, Mn, Cr, Pb and Cd) in some organs of tench and tissues of its parasite found in Kovada Lake (Turkey) were analyzed using atomic absorption spectrophotometry and subsequently compared with the data from sediments and water. Only Cu, Fe, Zn and Mn were detected in water, sediment, plerocercoids of Ligula intestinalis and fish samples, while levels of Cr, Pb and Cd were below the detection limits. Four elements were found at higher concentrations in the plerocercoid than in different fish tissues (muscle, liver and gill), being 1.6-37.4 times higher than that measured in muscle, liver and gill. Significant positive (for Cu) and negative (for Fe, Zn and Mn) correlations were found between the quantity of heavy metals in water and tissues of L. intestinalis plerocercoids while there were significant positive (for Cu and Zn) and negative (for Fe and Mn) correlations between the quantity of heavy metals in bottom sediment and tissues of L. intestinalis plerocercoids. Cestodes were found suitable to reflect the amount heavy metals in sediments, providing more reliable information about the actual pollution of the reservoirs.