The Structure of a Free-living Nematode Community in Wrangel Bay of the Sea of Japan

The qualitative composition and distribution of the meiobenthos in Wrangel Bay (Nakhodka Bay of the Sea of Japan) depend on the bottom sediment grain composition and on the concentration of heavy metals in the ground. It was established that the meiobenthos in the bay was represented by 13 groups of animals (class, order) and was relatively evenly distributed. The nematodes dominated (50–80%), and their settlement density was slightly higher in silty ground than in silty–sandy ground. Forty-eight species of nematodes were found; Dorylaimopsis peculiaris, Viscosia stenostoma, Axonolaimus seticaudatus, Metasphaerolaimus japonicus, and Pseudosteineria inaequispiclata dominated in the silty–sandy sediments; Sabatieria pulchra, S. palmaris, Metalaimus pumilus, Sphaerolaimus limosus, and Oncholaimium ramosum dominated in the silty ground. A slightly expressed correlation of the settlement density with the ground type and lead concentration in the bottom sediments emerged for two species (S. pulchra and S. palmaris).     

Heavy Metal Partitioning in Bottom Sediments of the Matanza-Riachuelo River and Main Tributary Streams

This study provides geochemical partitioning, potential bioavailability, and enrichment of Cd, Cu, Pb, and Zn in bottom sediments collected from the Matanza-Riachuelo River and its main tributary streams. A modified Tessier sequential extraction procedure, complemented with acid volatile sulfide (AVS) and simultaneous extracted metals (SEM) measurements, was applied to determine the partitioning of metals into four fractions (metals bound to amorphous sulfide, carbonate, and exchangeable), bound to Fe/Mn oxides (reducible), bound to organic matter/sulfide (oxidizable) and residual. Spatial and vertical distributions of metals were studied. The core sediments show a decreasing concentration of metals with depth. In top sediments, non-residual Cu was mainly associated with oxidizable phase, whereas Pb, Cd, and Zn were mainly associated with amorphous sulfide. Pb exhibited the highest enrichment in all sites. The ratio AVS/SEM was greater than one at sediment sections close to the water column, indicating that metals extracted with hydrochloric acid were mainly associated with the amorphous sulfide. The strong influence of amorphous sulfide in the retention of Cd, Pb, and Zn in anoxic sediments of Matanza-Riachuelo river system suggests that dredging and aeration could lead to the remobilization of metals from sediments to the water column, hence making the metals more available to the biota.     

Heavy Metals in the Tissues of Commercially Important Fish of Amurskii Bay,Sea of Japan

The concentrations of iron, copper, zinc, manganese, cadmium, and mercury in tissues and organs of Pacific herring, Far Eastern navaga, and spotted flounder from Amurskii Bay, Sea of Japan, were determined using an atom-absorption method. The distribution of these elements has been studied in organisms of the fish. The greatest concentration of iron, copper, cadmium, and mercury is found in the liver of the fish, manganese is mostly accumulated in the bone tissue, and zinc is found in the skin. Some specific features of metal accumulation in the fish of Amurskii Bay have been revealed. For example, the concentration of iron in the liver of herring and flounder significantly increased the mean concentration known from other areas. A sanitary–hygienic evaluation is provided for the recent levels of metal concentrations in these three species of commercially important fish.     

Assessment of Toxic Metal Contamination of Bottom Sediments in Water Bodies in Urban Areas

A study was carried out on 20 water bodies of the same origin in southern Poland. The study objectives included the assessment of toxic metal contamination in the bottom sediments of the water bodies in comparison with the geochemical background and sediments found in the substrate (i.e., vicinity) of the water bodies (i.e., the formations present in the surroundings of the water body itself), thus demonstrating the scale of anthropogenic enrichment of bottom sediments with toxic metals and assessing the cumulative impact on water bodies. The following amounts of toxic metals were found in the bottom sediments of the water bodies examined: 181.7–35200.0 ppm for zinc, 33.3–1648.8 ppm for lead, 1.8–359 ppm for cadmium, 14.0–271.5 ppm for copper, 45.3–167.5 ppm for chromium, and 12–128.5 ppm for nickel. Ratios of the values measured to the geochemical background were as follows: 0.7–135.9 (Zn), 0.6–53.0 (Pb), 0.7–143.6 (Cd), 0.9–18.1 (Cu), 5.0–18.6 (Cr), 1.1–11.7 (Ni).     

Heavy Metals in Seagrasses and Algae of Pos'et Bay, Sea of Japan

The contents of heavy metals in Sargassum algae and seagrasses from Pos'et Bay in the Sea of Japan were studied. The concentrations of Fe, Mn, Cu, Zn, and Cr in the algae and seagrass leaves were correlated with each other. The concentrations of heavy metals in brown algae and seagrasses from Pos'et Bay were largely close to background levels. Increased contents of some metals found in macrophytes in the area of the port of Pos'et were due to local environmental pollution; around Furugel'm Island, to periodical upwelling and drift currents from the mouth of the Tumannaya River; and, at Cape Deger, to the cyclonic current.     

Distribution,Speciation and Bioaccumulation of Hg and As in Mariculture Sediments from Dongshan Bay,China

Hg and As are the major hazardous pollutants in marine sediments due to their high toxicity to benthonic organisms. Understanding the spatial distribution, speciation and bioaccumulation of these toxic elements in sediments is therefore of high environmental importance for identifying their potential risks. Sediments and bivalves Paphia undulata were collected from the mariculture area of Dongshan Bay, China, for characterizing geochemistry (by using the European Community Bureau of Reference (BCR) sequential extraction procedure) and bioaccumulation of Hg and As [by calculating the biota sediment accumulation factor (BSAF)]. Both elements in sediments were mostly associated with the residual fraction (69.52–95.06% and 88.22–91.12% of the total concentration, respectively), followed by the oxidizable (bound to sulfides and organic matter) fraction (1.25–25.32% and 3.62–6.00%, respectively). However, Hg presented a higher bioaccumulation than As. Correlation analysis indicated that As in residual fraction and Hg in oxidizable fraction exert positive contributions (R = 0.927, P < 0.01 and R = 0.869, P < 0.05, respectively) on their own bioaccumulation factor. This indicated that P. undulata could adsorb both Hg in organic fraction and As in residual fraction from the sediments. Therefore, we should pay more attention to the potential dissolution and release of metals bound to sediments in the digestive tracts of marine organisms.     

Heavy Metal Accumulation in Four Species of Sea Turtles from the Baja California Peninsula, Mexico

Heavy metals were assessed in four species of sea turtles from the Baja California Peninsula, Mexico, representing the first report of heavy metal concentrations in tissues of post-yearling sea turtles from the Eastern Pacific. Concentrations of Cd measured in C. mydas kidney (653 μg/g dry wt) were the highest ever reported for any sea turtle species. Cd accumulated preferentially in kidney and the ratios of kidney to liver Cd in Baja California turtles were among the highest reported for sea turtles globally. Zn, Ni, and Mn concentrations were also significantly higher in kidney than other tissues, while Cu and Fe were greatest in liver, and all metals were lowest in muscle. With the exception of one value (69.9 μg/g in kidney of C. caretta), Pb was low in all tissues from Baja California. In comparisons across species, kidney of C. mydas had greater Zn and Ni concentrations as compared to other species, although there was no difference in liver metal levels among the species. Positive correlations were detected in the concentrations of Cd, Cu and Ni with the straight carapace length of C. caretta.     

Sediment Heavy Metal Contents,Ostracod Toxicity and Risk Assessment in Tropical Freshwater Lakes,Tamil Nadu,India

ABSTRACT

Coimbatore is one of the industrial cities in Tamil Nadu, India, which has been experiencing rapid urbanization and population growth. Coimbatore is also known for its unique freshwater lakes environment and serves as a rich ecosystem. However, the assessment of heavy metal levels in aquatic environments is limited. This study was aimed to investigate physicochemical parameters, heavy metals level and sources, and ecotoxicity in sediments collected from five different lakes in Coimbatore. The concentrations of heavy metals (Cr, Cu, Zn, As, Cd, and Pb) in sediments were determined by Inductive Coupled Plasma-Mass Spectroscopy (ICP-MS). Hg level was measured using Advanced Mercury Analyzer (AMA). The determined heavy metal concentrations in sediments varied significantly according to the lake location and consistent with local human linked anthropogenic activities. The metal concentrations in urban lakes were exceeding both the Sediment Quality Guidelines (SQGs) and the probable effect levels” (PELs) mostly; e.g., in sediments from the Lake Ukkadam, the values of 5.08 and 203.32 mg kg-1 dry weight were observed for Hg and Cu, respectively. The ecotoxicity test with ostracods exposed to the sediment samples revealed that mortality ranged between 6 and 23% for countryside lakes and 28 and 88% for the lakes within urban Zone. We used Spearman rank-order correlation and Principal components analysis (PCA) to assess the sources of pollutants and if they related to anthropogenic pressure and eutrophication of lakes. The main sources of heavy metals from studied lakes differed significantly. Urban and industrial effluents were dominant sources in urban lakes. Agricultural runoff, domestic wastes, and natural weathering were responsible for the metal sources in country lakes. This study provides baseline information on the heavy metal pollution status of sediments in the freshwater lakes in Coimbatore, which will be useful for pollution control measures to prevent possible metal sources on these lakes and impose appropriate management practices and continuous monitoring by relevant authorities.     

Assessment of Heavy Metal Mobility in Dredged Sediments: Porewater Analysis,Single and Sequential Extractions

Dredged sediments from the Leie catchment (Belgium) that were deposited on land between 70 and 10 years ago were characterized according to their physico-chemical properties, total metal concentrations and porewater composition. Actual and potential heavy metal availability was assessed by means of single extractions with 0.01 M CaCl ₂ , 0.05 M EDTA and 0.43 M acetic acid. A modified version of the BCR (Community Bureau of Reference) extraction procedure, adapted to the elevated acid neutralizing capacity of the sediments, was applied. Information on element mobility was assessed and the used methodologies were critically evaluated.

The favorable physico-chemical characteristics of dredged sediments from the catchment of the Leie River (N-Belgium) indicated a rather low actual heavy metal mobility. Based on CaCl ₂ and EDTA extractions, the distribution of Cd, Zn and Ni between the solution and sorbed phase could be described as a function of pH and organic carbon content. Cd and Zn were found to be the elements with the highest potential availability, while Cu and Ni displayed a medium availability. It is stressed that different types of extractions deal with heavy metal mobility in a different way and that the measurement of “key-factors” such as the pH of the extracts can be helpful for the interpretation of the results.     

Metal Speciation and Contamination in Dredged Harbor Sediments from Kaohsiung Harbor,Taiwan

The status of metal speciation and contamination of sediments in Kaohsiung Harbor, Taiwan, was evaluated by a five-step sequential extraction procedure (exchangeable, carbonate, Fe–Mn oxides, organic matter, and residual). Eleven dredged sediment samples from various locations in the harbor were characterized in terms of heavy metals, grain size, and total organic carbons. Results showed that Hg, Pb, Cd, Cr, Cu, Zn, Ni, and Mn had different species composition patterns. The degree of sediment contamination was determined for an individual contamination factor (ICF) and a global contamination factor (GCF); results showed that Kaohsiung Harbor had a high potential risk for Pb, Cd, Cr, and Cu. Based on GCF values, the results showed that those stations, located in the vicinity of the river mouth, fish port, and industrial sites, contributed high potential risk to Kaohsiung Harbor. The potential risk of heavy metals to the environment was assessed for risk using the risk assessment code (RAC) and results showed that Pb, Cd, Zn, and Mn generally created a medium to high risk, and Hg, Cr, Cu, and Ni generally created a low to medium risk.     

Species composition and distribution of free-living marine nematodes in Vostok Bay, Sea of Japan

The qualitative and quantitative composition of free-living marine nematodes have been studied in Vostok Bay (Peter the Great Bay, Sea of Japan). It is found that the population density of nematodes in the bottom sediments of Vostok Bay shows an uneven distribution. The mean population density equaled 56800 ± 23400 specimens/m². A correlation has been revealed between the population density of nematodes and the substrate type. Altogether, 85 species of nematodes have been found; they were dominated by Sabatieria palmaris, Rhabdodemania orientalis, Araeolaimus parvibulbosus, Oncholaimium paraolium, Doryolaimopsis peculiaris, and Metachromadora itoi. Six taxocenoses of nematodes were distinguished, taking into account the species dominating in the population density and using cluster analysis of the obtained data. The dominating trophic assemblage of nematodes was “scrapers.” In general, the species composition of nematodes in Vostok Bay is characterized by the relatively great similarity with that in other areas of Peter the Great Bay (Sea of Japan).     

Accumulation of Heavy Metals in Water,Sediments and Wetland Plants of Kizilirmak Delta (Samsun,Turkey)

In this study, concentrations of heavy metals (Fe, Mn, Ni, Co, Zn, Cu, and Pb) were measured in water bodies including streams, bottom sediments and various wetland plants of K?z?l?rmak Delta. K?z?l?rmak Delta is one of the largest and the most important natural wetlands in Turkey and has been protected by Ramsar convention since 1993. The heavy metal concentrations in water were found lower than that of national standards for protected lakes and reserves. In bottom sediments and wetland plants, however, the accumulated amounts of different heavy metals varied in the following order: Fe>Mn>Zn>Ni>Co>Cu>Pb, and Fe>Mn>Zn>Ni>Co respectively. Heavy metal uptake of Hydrocharis morsus-ranae and Myriophyllum verticillatum plants among others were found far above the toxic levels and they might be used as bio-indicators and heavy metal accumulators in polluted natural areas.     

Heavy Metal Accumulation and Distribution in Organs of the Mussel Crenomytilus grayanus from Upwelling Areas of the Sea of Okhotsk and the Sea of Japan

The subcellular and cytosolic distribution of Zn, Fe, Ni, Cu, Mn, Cd, and Pb in the digestive gland and kidney of the mussel Crenomytilus grayanus from upwelling areas of the Sea of Okhotsk and the Sea of Japan was studied. Cd, Zn, Pb, and Ni have accumulated in the kidneys of mussels from these areas. When the concentrations of both essential and toxic metals in the mussel organs had increased significantly, their redistribution into the cytosol took place. Gel chromatography of cytosolic proteins in the kidneys of mussels sampled in the area with a strong stationary upwelling revealed metallothioneins. This is uncommon for bivalve mollusks from unpolluted areas. High molecular weight proteins act as preliminary ligands for Cd.     

Foraminifera and Nematoda community within the area of Ahnfeltia tobuchiensis field in Stark Strait (Peter the Great Bay of the Sea of Japan)

In August of 2006 in Stark Strait (in the Peter the Great Bay) Foraminifera and Nematoda communities were investigated at two stations: in bottom under a red alga Ahnfeltia tobuchiensis bed and on a site located outside of the bed. Bottom sediments at the stations are represented by sands of various silting extent. Foraminifera dominated at both stations, the second place by abundance was occupied by Nematoda. Extremely high population density of meiobenthos, 14278.9 ± 4623.1 thousand sp./m², was observed under the Ahnfeltia bed. The foraminifera percentage was 98.1%, which was probably connected with the mass development of diatom algae on Ahnfeltia. A high degree of domination of one Foraminifera species was recorded—Cribroelphidium frigidum. Nematoda constituted 1.5% with the prevalence of Comesomatidae family representatives. At the station situated outside of Ahnfeltia field mean population density of meiobenthos was an order lower—1731.8 ± 621.3 thousand sp./m². Foraminifera constituted 63.8% of the total meiobenthos density with Eggerella advena as the dominating species. Among Nematoda (12.5%) Paracanthonchus macrodon, Axonolaimus seticaudatus and Monoposthia latiannulata were dominant. Foraminifera and Nematoda community under Ahnfeltia bed, where bottom sediments are more silted, had low indices of species diversity and a high degree of domination.     

Concentrations of Heavy Metals in Soft Tissues of the Gastropod Nucella heyseanain the Vicinity of Vladivostok and in the Vostok Bay Reserve

A survey was made of 168 specimens of the gastropod mollusk Nucella heyseanafrom 5 samples collected in Amurskii Bay and Vostok Bay (Peter the Great Bay and the Sea of Japan). The variability of Cu, Zn, Cd, Pb, Fe, and Mn contents in gastropod soft tissues was analyzed. The statistic concentrations of the six metals differed significantly among the samples; they were sometimes taken at a distance of a mere several tens of meters apart. N. heyseanacollected near Vladivostok generally had higher concentrations of heavy metals; however, the amount of Zn in the specimens of one sample from the Vostok Bay Reserve was 400 g/g, which is two times greater than that of mollusks from the urbanized zone. The canonical and discriminant analyses and the analysis of the variance indicate that the variation in heavy metal concentration within groups of mollusks (within bays) is comparable in magnitude with the variation among the groups.     

Assessment of Heavy Metal Pollution in Water and Sediments from the Ghalechay River,Baychebagh Copper Mine Area,Iran

The concentrations of selected heavy metals in sediments and waters in Baychebagh copper mine were determined using ICP-OES. Except for Co, the average concentrations of Cd, Cu, Pb, and Zn in sediments from the Ghalechay River in the district exceed the world-average shale and continental upper crust value. Enrichment factors for Pb, Cu, and Cd were significantly enriched in sediments, indicating environmental contamination. Geoaccumulation index calculated for different sampling stations indicates that the sediments are unpolluted with respect to Co and Zn while unpolluted to moderately polluted with Cu and highly polluted with Pb and Cd. The Sediment Quality Guidelines (SQGs) suggest that Cd and Pb may pose the highest risk for the environment. Sequential extraction analyses of sediments revealed that Cu, Co, Pb, and Zn bound to extractable, carbonate, reducible and oxidizable fractions are lower than residual fraction. About 10% of the total Pb was associated with the exchangeable fraction, indicating remobilization, while Cd (89%), Pb (73%) Co (58%), Cu (76%), and Zn (68%) closely associated with the residual and oxidizable fractions, resulting in their environmental immobility. The residual forms are not expected to be released under normal conditions in the river and could be considered an inert phase.     

Assessment of Heavy Metal Contamination in the Sediments of the Shuangtaizi Estuary Using Multivariate Statistical Techniques

In order to assess heavy metal pollution of sediment samples collected from Shuangtaizi estuary, contamination factor (CF) and multivariate statistical analyses, including principal component analysis (PCA), cluster analysis (CA) and correlation analysis, are carried out in this paper. CF confirms that Pb, Cu and Hg concentrations are very low and all fall within the range of background, while Zn and Cd demonstrate moderate contamination (in A10, A13, A15, A16 and A17 sites) and very high contamination (in A10, A13, A15 and A17 sites), respectively. The PCA indicates that four significant principal components (PCs) are extracted, explaining 88.959% of total variance, which suggests that Pb, Cu and Zn are mainly associated with organic carbon (OC). The result from CA is consistent with that obtained from PCA, classifying that the heavy metals in two clusters derive from different sources. Correlation analysis supports the conclusions from PCA and CA, elucidating the relationships between heavy metals and particle sizes of the sediments.     

The Effect of Metal Concentration in Bottom Sediments on the Accumulation of Metals by the Mytilids Crenomytilus grayanus and Modiolus kurilensis

The relationship between the concentration of Pb, Cu, Cd, Zn, and Ag in soft tissues of mytilids Crenomytilus grayanus and Modiolus kurilensis and in bottom deposits was studied to determine the potential and limitations in the use of these molluscs as bioindicators of contamination of coastal waters near Vladivostok (northwest of the Sea of Japan). It was found that the mussel C. grayanus began to accumulate Pb and Cu after certain threshold concentrations of these metals (60 and 150 g/g respectively) in fine fractions of sediments was reached. Accumulation of Pb and Cu by M. kurilensis also depended on the level of sediment contamination, but the higher initial metal content in tissues and the higher individual variability reduced the sensitivity of this species as a bioindicator. Accumulation of Cd and especially of Zn in mytilid tissues is adjusted by the organism, which restricts the opportunity of their use for tracking the anthropogenic input of bioavailable forms of these metals.     

Seasonal Dynamics of Soft Bottom Macrobenthic Communities of the Sublittoral in Peter the Great Bay, Sea of Japan

Seasonal dynamics of macrobenthos were studied at five stations located at depths of 10–60 min in the Far East State Marine Reserve (southern Peter the Great Bay) during 1984–1987. Sampling was conducted at stations once per season. Stable seasonal fluctuations of the population density and the biomass in basic taxonomic groups were found. As a rule, the quantitative parameters were augmented in spring and summer, and decreased in fall and winter. This was caused, first of all, by summer fluctuations of the number of small and short-lived species of polychaetes and bivalve molluscs. The amplitude of fluctuations decreased with increasing depth. Variation in the quantitative parameters was significant at the community level only at the most shallow-water stations. It was assumed that this phenomenon might be caused by the seasonal consumption of macrobenthos by bottom fish and by the periodicity of detritus supply to the bottom from the water column with a background of varying environmental temperature parameters and of mass settling of benthic larvae. The seasonal changes in parameters began and ceased earlier in 1986–1987 than 1984–1985, which was related to an appreciable decrease in water temperature in 1986. During the period of study, an increasing trend of parameters, apparently part of a long-term cycle, was recorded both for individual groups and for entire communities, and was the most appreciable at greater depths (47–60 m).     

Distribution of Saprophytic Bacteria in the Atomic Submarine Accident Zone in Chazhma Bay, Sea of Japan

The numerical and taxonomic composition of saprophytic bacteria was studied in the atomic submarine accident zone in Chazhma Bay. With increasing depth in the epicenter of the accident zone, the mean of the ratio of bacterial taxa in the resistance series tends toward a constant. The numerical structure of the pelagic saprophytic bacterial assemblage becomes ordered as the bottom is approached. Analysis of radioactive suspended matter allowed us to obtain model distribution of numbers of all saprophytes and each taxon from the different environmental sources (sediment surface and upper layers of the sea).Original Russian Text Copyright © 2005 by Biologiya Morya, Ivanova, Gorshkova, Mikhailov, Sergeev, Gladkikh, Goryachev, Dudarev, Botsul, Mozherovsky, Slinko, Kiselev.