Pollution Levels In Sediments Research Articles

Accumulation of microplastics in various organs of fiddler crabs and sea cucumbers across the coastal habitats in Singapore.

Microplastics (or MPs) are an emergent threat to marine organisms. This study assessed MP contamination in the major organs of four species from Singapore's coastal habitats: Orange Fiddler Crab (Gelasimus vocans) and Porcelain Fiddler Crab (Austruca annulipes) from mangroves, Garlic Bread Sea Cucumber (Holothuria scabra) from seagrass beds and Synaptid Sea Cucumber (Synaptula recta) from coral reefs. MPs were prevalent in all species and their organs. Mean MP concentrations in fiddler crabs were 6.63 ± 0.97 MP individual-1 in G. vocans and 12.18 ± 3.38 MP individual-1 in A. annulipes, where their female crabs had significantly more MPs than males. This study also confirmed the translocation of MPs to the crabs' hepatopancreas, which had the highest MP concentrations compared to gills and digestive tracts. These observations suggest that the fiddler crabs' sexual dimorphism could influence feeding efficiency and behaviour. In contrast, the sea cucumbers had lower MP concentrations in their organs, where the average MP concentrations were 10.00 ± 2.32 MP individual-1 in H. scabra and 6.33 ± 0.69 MP individual-1 in S. recta. For H. scabra only, their respiratory trees showed the highest MP levels compared to their digestive tracts. Across the species, MPs were predominantly <1,000μm in size, in fibre shape and polyethylene (PE). These findings provide critical baseline data on MP contamination across different organs in marine organisms, serving as proxies for sediment pollution levels.

Pollution and Ecological Risk Assessment of Potentially Toxic Elements in Sediments Along the Fluvial-to-Marine Transition Zone of the Don River

The quality of sediments in the mixing zone of river freshwater and marine saline water as an important geochemical barrier for potentially toxic elements (PTEs) remains poorly understood. This study aims to analyze the current pollution with PTEs and associated ecological risks in sediments of the Don River delta and the surrounding area of the Taganrog Bay of the Sea of Azov (Russia). The PTE content was determined in fifty-four collected samples using the WDXRF and assessed using geochemical and ecotoxicological indicators. The source of Cr, Mn, Ni and Pb is mainly river runoff, and Cu, Zn and Cd are from a variety of anthropogenic sources. As shown by the assessment of the geoaccumulation index (Igeo), single pollution index (PI) and contamination factor (CF), these elements are the priority pollutants. According to these estimates, high and very high contamination of sediments in the estuarine zone of the Don River with Cd and Pb was detected in 72–94% and 2–57% of samples, respectively. However, environmental risks are determined almost exclusively by the level of Cd. Total contamination as assessed by the Nemerow pollution index (NPI), modified degree of contamination (mCd) and metal pollution index (MPI) is of concern in 83–98% of the samples studied. The most heavily polluted sediments are in the vicinity of residential areas of the Taganrog Bay. Despite the lower average pollution levels of deltaic sediments, freshwater biota are exposed to higher potential toxic risks of adverse effects by PTE, particularly from Ni and Pb. Thus, the complex hydrological regime and uneven anthropogenic impact predetermine the geochemical state of the sediments of the estuarine zone of the Don River.

Spatial and Temporal Variations in Heavy Metals in Lake and Reservoir Sediments in China: A Pollution Status and Risk Assessment

As ubiquitous pollutants, understanding the levels of contamination, eco-risks, and potential sources of heavy metals in lake and reservoir sediments is essential for the development of pollution control policies to ensure the ecological safety of the aquatic environment. However, large-scale studies of heavy metal elements in sediments face many limitations, and most of them are characterized as small and staged. Therefore, in order to evaluate the level of heavy metal contamination in lake and reservoir sediments in China and to explore the pattern of spatial distribution of heavy metals, this article systematically collected the concentrations of seven heavy metals, Pb, Cd, Hg, Cr, As, Zn, and Cu, in the sediments of the lakes and reservoirs in question since 2000, evaluated the calculation of the accumulation index and the assessment of health risk, analyzed the spatial and temporal variations, and conducted a preliminary investigation of the sources. The results of the study showed that the contents of the seven elements were higher than the national soil pollution control standards, and various elements were enriched to different degrees, among which Cd and Hg exceeded the standard more seriously. The overall pollution level of reservoir sediments was lower than that of lake sediments, and the pollution of reservoirs was relatively light; from the distribution characteristics, the pollution level and ecological risk of different heavy metal elements showed an obvious imbalance in distribution. The heavy metal concentration, ground accumulation index, and ecological risk in the southern region are overall high. There is a good agreement with the Hu Huanyong line; from the historical change characteristics, except for the average Igeo of Hg, which shows an obvious upward trend, the average Igeo of several other heavy metals basically shows a decreasing or stable trend; the sources of heavy metals are complex and extensive in terms of the national scale, and industry, transportation, and agriculture are the main sources.

Evaluation of heavy metals pollution in recent sediments of Zoubia Wadi, W-Skikda (NE of Algeria)

This study aims to evaluate the level of metallic pollution in the recent sediments of the Zoubia area (Ain Kechera) in north-east of Algeria. The method used for this assessment involves sediments sampling and the determination of heavy metal concentrations. The study estimated the level of metallic pollution in the sediments by calculating several pollution indexes, including the contamination factor (CF), the enrichment factor (FE), the geo-accumulation index (Igeo), the individual ecological risk index (), the potential ecological risk (RI) and statistical analysis of the data. The study monitored seven trace metals: cadmium (Cd), chromium (Cr), nickel (Ni), lead (Pb), zinc (Zn) and copper (Cu). The results indicate an enrichment of Cd, Pb, Zn, and Cu in all samples. However, Ni, Co, and Cr levels are below those of the continental crust (background). The geo-accumulation index values for Co, Ni, and Cr are negative in all samples. On the other hand, positive geo-accumulation index values were observed for Cd, Pb, Zn, and some Cu samples (B1, B2, B3, and B4) with individual ecological risks of less than 40 for Cd, (94.48–119.21) for Zn, and (80.23–135.4) for Cu, respectively. This indicates low risk for Cd and high risk for Zn and Cu. The results indicate that Pb poses a significant ecological risk (537.4–842.05) and may have adverse effects on human health. The most significant pollutants, in order of increasing risk, are Pb, Cu, Zn, and Cd.

Assessment of Microplastic Pollution in River Ecosystems: Effect of Land Use and Biotic Indices

The proximity of freshwater ecosystems to anthropogenic activities makes them one of the most threatened environments by plastic pollution in the form of microplastics (MPs). Therefore, it is crucial to identify the primary drivers of MP dynamics in rivers to enhance their management. This work analyzed the concentration of MPs in water and sediments and evaluated the influence of land use and its relationship with the main biotic indices employed to assess the water quality of rivers. This research was carried out in four different catchments, with three sampling points established in each river basin. The results revealed that MPs were ubiquitous across all locations, with concentrations ranging from 0.10 to 35.22 items m−3 in waters and from 26 to 643 items Kg−1 in sediments. The highest concentration of MPs both in water and sediments were found in the Lagares River (35.22 items m−3 and 643 items Kg−1), while the lowest concentrations were found in the Miñor River for water (0.10 items m−3) and Tea River for sediments (138 items Kg−1). Urbanization degree was identified as the primary driver of MP pollution in water, whereas population density correlated with sediment pollution levels. These findings explain the elevated MPs abundance in the more urbanized and populated Gafos and Lagares rivers compared to the relatively pristine Miñor and Tea rivers. Furthermore, the presence of MPs in sediments was found to negatively impact the most sensitive benthic macroinvertebrate taxa, as evidenced by lower values of the IASPT and EPT indices at sampling points with higher sediment MPs concentrations (Gafos and Lagares).

Evaluation of pollution levels in sediments from Lake Edku, Egypt using laser ablation inductively coupled plasma mass spectrometry

The concentrations of 11 heavy metals in sediments from Lake Edku, Egypt were determined using LA-ICP-MS. The average concentrations of elements occurred in the order of Fe > V > Cr > Zn > Ni > Cu > Co > Pb > As > Sn > Mo with respective values of 4.67 %, 104.8, 77.9, 76.6, 59.2, 52, 27.8, 19.8, 4.14, 2.24, and 1.45 μg/g. Several pollution indices were used to evaluate individual and cumulative contamination levels. All HMs were found to be in the deficiency to minimal enrichment range based on the enrichment factor. The contamination factor indicated low contamination levels of Cr and As, low to moderate contamination levels of Fe, Ni, Zn, Mo, Sn, and Pb, and moderate contamination levels of Co and Cu. The pollution load index and contamination degree indicated the sediments to be polluted and moderately polluted, respectively.

Lead Level Analysis in Roots and Leaves of Mangrove Plants Ceriops tagal and Rhizophora apiculata in Clungup Mangrove Conservation

Indonesia is an archipelago with more water than land, which is battling water and land pollution. One form of pollution is lead which is commonly caused by battery waste, fishing boat activities, diesel waste. One solution is phytoremediation using hyperaccumulator plants such as mangroves. Mangroves can absorb heavy metals and maintain ecosystem stability. The dominant species in Clungup Mangrove Conservation are Ceriops tagal and Rhizophora apiculata. The objectives of this study were: 1) To determine the level of lead metal (Pb) pollution in mangrove sediments in the area. 2) To determine the levels of lead metal (Pb) in the roots and leaves of mangrove species Ceriops tagal and Rhizophora apiculata. 3) To determine the ability of lead metal (Pb) absorption in mangrove plants Rhizophora apiculata and Ceriops tagal. Research activities began on February 20th - May 31th, 2023. The research was conducted at Clungup Mangrove Conservation in Sumbermanjing Wetan District, Malang Regency. Lab tests were conducted at the Unism Integrated Laboratory and Halal Center. Lead test results in sediments in this area are classified as very low. Lead levels in the roots of Ceriops tagal were higher than Rhizophora apiculata. Pb levels in the leaves of Ceriops tagal were also higher than the leaves of Rhizophora apiculata. Bioconcentration Factor (BCF) values were higher than Rhizophora apiculata, but both were categorized as lead removal plants (BCF &lt; 1). The Transfer Factor (TF) value showed a lower value for Ceriops tagal than Rhizophora apiculata, indicating that Rhizophora apiculata has better translocation ability. However, both are categorized as unstable plants (TF &lt; 1). The results of the phytoremediation calculations showed that Ceriops tagal had superior absorption potential compared to Rhizophora apiculata.

Assessing the ecological and health risks associated with heavy metal pollution levels in sediments of Big Giftun and Abu Minqar Islands, East Hurghada, Red Sea, Egypt

This study assessed pollution levels, ecological and health risk, and spatial distribution of eight heavy metals in sediments of Big Giftun and Abu Minqar Islands, Red Sea, Egypt. Iron (Fe) and manganese (Mn) had the highest contents in both island sediments, while cobalt (Co) in Big Giftun and cadmium (Cd) in Abu Mingar had the lowest values. The obtained PCA data exhibited positively significant loadings of Cd, Co, copper (Cu), nickel (Ni), and zinc (Zn) with 51.03 % of data variance in Big Giftun, and lead (Pb), Cu, Mn, Ni, Zn, and Fe (37.7 %) in Abu Minqar sediments. The contamination factor (CF) showed low contamination for all metals, except cadmium; Cd (moderate). The geo-accumulation index (Igeo) values showed uncontaminated (Cd, Co), moderately (Cu), extremely contaminated (Fe, Mn) (Igeo > 5) in Big Giftun, and uncontaminated (Cd), moderately to strongly contaminated (Cu, Ni), and extremely contaminated (Fe, Mn, and Zn) in Abu Minqar sediments. The pollution load index (PLI) values indicated baseline level of contamination (PLI <1), and degree of contamination (DC) indicated low degree of contamination (DC < n) in all sediments. Nemerow pollution index (NPI) showed unpolluted sediments in Abu Minqar (NPI ≤1) and slight pollution (1 < NPI ≤2) in Big Giftun. Cd showed moderate potential ecological risk (40 ≤ Eri < 80) in Big Giftun sediments. Potential ecological risk index (PERI) indicated low risk sediments (PERI <150). Mean effects range median quotient (MERMQ) indicated low-priority risk of toxicity (MERMQ ≤0.1), and toxic risk index (TRI) showed no toxic risk in all sediments (TRI <5). The modified hazard quotient (mHQ) indicated very low severity of contamination (mHQ <0.5). The hazard quotient (HQ) levels of all metals were below the safe value (HQ <1). The hazard index (HI) levels indicated that no chronic risks occur (HI <1). The total cancer risk (TCR) for all metals were below the safe level (1 × 10−4) of the United States Environmental Protection Agency (U.S. EPA) guidelines.

A methodology for evaluating the relative pollution level of metal pollution in surface sediments of rivers based on the statistical results of relevant literatures covering world-wide rivers

Due to the intervention of human activities, the background values of riverbed sediment exhibit spatiotemporal variability, which can affect the accuracy of risk assessment results. Using risk assessment that do not rely on background values is an executable alternative to avoid such problems. In this study, a relative pollution level assessment (RPLA) method which was based on the statistical results of relevant literatures was proposed. This method includes a four-step data processing procedure to extract the evaluation indexes of relative pollution degree of pollutants in environment and a series of relative pollution status assessment methods to evaluate the overall relative pollution level and regional difference of world-wide rivers. To demonstrate how to use RPLA method, 310 relevant literatures covering world-wide rivers were selected. And the ambient background value (x̅), the world-wide threshold values (WWTV) and the relative pollution grades (LEVEL I ∼ IV) of 9 target metals (Cr, Ni, Cu, Zn, As, Cd, Pb, Sb and Tl) in riverbed surface sediments of world-wide rivers were extracted and used for evaluation. Moreover, the stability and applicability of RPLA method were evaluated. Results show that the evaluation results of RPLA method are robust and comparable with traditional evaluation method.

Revealing the hidden burden for lake management: the sediment phosphorus storage pools in Eastern Plain Lake Zone, China.

As one of the essential components in ecosystems, lakes play a major role in the global phosphorus (P) cycle. It is helpful for further understanding of the inside lake P geochemical cycle to research P pollution and storage in lakes, which is of positive significance for lake eutrophication restoration. In this study, we investigated the total phosphorus concentrations (TPC) of water and sediments from 37 lakes in the Eastern Plain Lake Zone (EPL) of China, evaluated the P pollution degree of lakes, and estimated P storage in lake sediments with quantitative data of lake area and number. The results indicate that the total phosphorus concentrations of water (TPCW) and total phosphorus concentrations of the surface sediments (0-1cm, TPCSS) in EPL were high, the mean values were 0.11mg·L-1 and 869.85mg·kg-1 respectively, with obvious differences between urban and rural areas, as well as between different river basins. Over half (56.76% and 70.27% respectively) of the lakes reached severe pollution levels in water and surface sediments. There were 16224 lakes (> 0.01 km2) with a total area of 21662.37 km2 in the EPL, and the P storage in the lake sediments (0-30cm) was about 4.87 ± 2.08 Tg (1 Tg = 1 × 1012g), accounting for about 2.74% of the basin soil. TPCW and TPCSS of lakes in the EPL were significantly positively correlated, may suggest a close nutrient cycling relationship between the lake water and the sediment. During periods of high winds and waves, the stored P in the top sediments in the EPL may continue to participate in the internal P geochemical cycle and migrate to the overlying water, posing a potential pollution hazard. Therefore, it is crucial to take into account the sediment P pools when formulating effective lake phosphorus management strategies.

Land use impact on mercury in sediments and macrophytes from a natural lake in the Brazilian savanna

Freshwater ecosystems are essential to human and wildlife survival. They harbor a wide biodiversity that contributes to ecosystem services. In the ecosystem of the Brazilian Savanna, anthropic activities related to environmental pollution that includes mercury (Hg) is of concern. We studied total mercury concentrations ([THg]) in bottom sediments and macrophytes to assess its short-term (2012 and 2019) impact on a natural lake. Temporal changes in [Hg] were assessed with the geoaccumulation index (Igeo) and the sediment quality guidelines (SQG). The land use index (LUI) was used to assess differences in anthropogenic activities and the Normalized Difference Aquatic Vegetation Index (NDAVI) was used to assess macrophyte biomass density. The bioaccumulation factor (BAF) was used to assess Hg accumulation in macrophytes relative to sediments. The LUI showed an increase in the intensity of agricultural activities in the vicinities of the lake. The NDAVI indicated an increase in the density of macrophytes in the evaluated period. The Igeo indicated that in all sampling sites, pollution levels in sediments increased in 2019 (Igeo > 0), with concentrations exceeding the SQG in 2019. In 2012, [THg] in sediments ranged from 20.7 to 74.6 ng g−1, and in 2019 they ranged from 129.1 to 318.2 ng g−1. In macrophytes, [THg] ranged from 14.0 to 42.1 ng g−1 in 2012, to 53.0 and 175.3 ng g−1 in 2019. [THg] in bottom sediments and macrophytes were significantly higher in the second collection period (p < 0.05). There was no significant difference in BAF values between the periods and no significant bioaccumulation in macrophytes (BAF <1). Our results demonstrated that the macrophytes are not sensitive indicators of Hg pollution in lentic environments of the Brazilian Savanna; however, the increased land use intensity (agriculture, automotive traffic, and urban infrastructure) could increase Hg accumulation in sediments and macrophytes in a short time interval.

Pollution profile, source identification, and risk assessments of persistent organic pollutants (POPs) and toxic elements in the sediments of one of the water supply areas (Sultanbahçedere lake) to Istanbul, Türkiye

This study was done to comprehensively exhibit the pollution level of surface sediments taken from Sultanbahçedere dam lake in terms of some persistent organic pollutants (POPs) and toxic elements, to decide the possible sources of polycyclic aromatic hydrocarbons (PAHs), to perform the ecological and human health risk assessments, and to evaluate the pollution profile with the hierarchically clustered heatmap (HCHM) analysis and principal component analysis (PCA). Naphthalene, Benzo(b)fluoranthene, Fluoranthene, Pyrene for PAHs; p,p-DDE, p,p-DDD, alpha-HCH, p,p-DDT, Endrin for OCPs; hexa and hepta chlorinated congeners accounting for 50.63% and 28.44% for polychlorinated biphenyls (PCBs); 1234678-HpCDD, OCDD for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs); PCB 118, PCB 105, PCB 167 for dioxin like-PCBs (DL-PCBs) and Al, Fe, Ca for elements were predominant in almost all of the sediments with a few exceptions. S4 site, which is one of the mid-sites of reservoir, has high concentrations in most of these pollutants. According to PAH diagnostic analysis, PAHs in the surface sediments are mostly affected by pyrogenic sources. The concentrations of POPs do not pose any toxic risk to aquatic organisms according to sediment quality guideline (SQG) and the limit values of other countries accepted in the world. Also, since none of the elements exceeded the effect range median (ERM) values, they do not pose a significant toxic risk to aquatic organisms. There is no risk for non-carcinogenic and carcinogenic hazards both for children and for adults considering hazard quotient (HQ), hazard index (HI), and lifetime cancer risk (LCR) values of all pollutants.

Variability and Heavy Metal Pollution Levels in Water and Bottom Sediments of the Liwiec and Muchawka Rivers (Poland)

In recent years, human impact on the Earth’s ecological environment has become increasingly visible, with serious negative consequences. One of the most important pollutants are heavy metals which can easily bind to sediments. Due to their toxic behavior, persistence, lack of biodegradability and bioaccumulation, they are considered key river pollutants that need to be controlled. This study examined two rivers: the Liwiec and Muchawka rivers located in south-eastern Poland. The mouth of the Liwiec River is the Bug River, which is partly the border between Poland and Belarus. In turn, the mouth of the Muchawka River is the Liwiec River. The objectives of the study were the following: (1) To complete a qualitative analysis of heavy metals (Cd, Pb, Cu, Ni, Zn) in the waters and bottom sediments of the Liwiec and Muchawka rivers; (2) To assess the degree of heavy metal contamination; (3) To identify the sources of contamination. The analysis included samples of surface water and bottom sediments collected (16 water and 16 bottom sediment samples were taken from the Muchawka River and 32 water and 32 bottom sediment samples were taken from the Liwiec River) in June and September 2022. The variability of characteristics, such as temperature, precipitation and humidity, contributes to seasonal changes in the distribution characteristics and sources of heavy metals. The study showed that only a small part of the heavy metals entering rivers are present in the water depth in the dissolved state, and most of them enrich the sediment, resulting in much higher concentrations of heavy metals in the sediment than in the water column. The differences in the distribution of some elements in water and sediment are due to the fact that surface sediments retain long-term records. Therefore, sediment can be considered a potential source of heavy metals in the aquatic environment. In general, the content of heavy metals determined in bottom sediments was not high but indicative of anthropogenic human activity. There is a possibility of re-release of heavy metals from the sediment into the water when hydrodynamic conditions or environmental factors (pH, redox potential, etc.) change, which could lead to secondary water pollution. The data obtained will be of great importance to both researchers studying river systems and the population living in the area.

Contamination and risk assessment of trace metals and As in surface sediments from abandoned gold mining sites of Bekao, Adamawa-Cameroon

This paper assesses the spatial distribution and the trace metal and As contamination in surface sediments along the Lom River in the abandoned gold mining sites of Bekao (Adamawa Cameroon). A total of thirty one (31) surface sediment samples is collected and analyzed to determine the concentrations of Cr, Mn, Fe, Ni, Cu, Zn, Sn, Pb and As. The results obtained are compared with the Average Shale Values (ASVs) and Sediment Quality Guidelines (SQGs) as the threshold effect concentration (TEC), the probable effect concentration (PEC), the Effect Range Low (ERL) and the Effect Range Median (ERM). To assess the trace metal and As pollution level in sediments, nine environmental pollution indices, namely geoaccumulation index (Igeo), enrichment factor EF, contamination factor (CF), contamination degree CD, modified degree of contamination (mCD), Nemerow index (NI), contamination severity index (CSI), probability of toxicity (MERMQ) and potential ecological risk RI are used. In addition, Pearson’s correlation matrix and General Linear Model (GLM) are used to determine the pollution indices which adjust better with the trace metals and As concentrations. The results reveal that the sequence of trace metals and As mean concentrations was Fe ¿ Mn ¿ Cu ¿ Ni ¿ Sn ¿ Cr ¿ Zn ¿ Pb ¿ As, and the mean concentrations of Zn, Ni, Sn, and Cu exceed the ASVs. Based on the sediments quality guidelines (SQGs), sediments are polluted in Ni and Cu. According to the Igeo, EF and CF, Sn and Cu reveal a high level of contamination with significant enrichment and Ni a moderate level of contamination and enrichment. The results of the calculation of CD, mCD, and NI indices suggest significant contamination, high contamination and high pollution of trace metals and As in sediments, respectively. Globally, CSI demonstrates an ultra-high severity contamination, MERMQ a high-medium priority with a toxic probability of 49% and RI show a moderate ecological risk. Pearson’s correlation matrix and GLM suggest that CSI and MERMQ are the indices which adjust better with trace metals and As in sediments.

Regional background determination and pollution assessment of heavy metals in the semi-closed Bohai Sea sediments

Background metal concentrations are important in assessing pollution level of marine sediments; however, they can be significantly altered by local depositional environments, resulting in significant errors in regional pollution assessment. This study was based on the investigation of the background levels of heavy metals in the Bohai Sea sediments using sediment core, 2-sigma outlier, and regression methods. We also estimate the ecological risks of heavy metals for surface sediments collected from the Bohai Sea using the three methods mentioned above. Ecological risks of heavy metals calculated using the regression method show wide disparities and significant differences from those calculated using the sediment core and 2-sigma methods, indicating that the regression method is not suitable for the Bohai Sea, likely as a result of its complex sources. Conversely, the estimated ecological risks using the sediment core method are moderate, and most heavy metals, except for Hg and Cd, have negligible contamination.

Sediment and interstitial water heavy metals in mangrove restoration wetland and preliminary exploration of microplastics in interstitial water

Compared with heavy metals in sediments, those in interstitial water can act as better indicators of bioavailability. Based on different planting densities, the distribution and risk of heavy metals (Zn, Cu, Ni, Cd) in the sediments and interstitial waters of “Kandelia obovata - Rhizophora stylosa - Bruguiera gymnorhiza” in a mangrove wetland restoration were studied, and the identification and analysis of microplastics in interstitial water were preliminarily explored. The results showed that the spatial distribution of heavy metals in sediments and interstitial waters in mangrove restoration wetlands varied greatly and was primarily affected by planting density and sediment properties. The geo-accumulation index, potential ecological risk index of a single trace metal, and comprehensive potential ecological risk index indicated that the level of Cd pollution in sediments was high. The results of the interstitial water criteria toxicity unit (IWCTU) and Nemerow index (NI) showed that the pollution level of heavy metals in interstitial water was generally high. Among them, the IWCTU values of Cu and Zn were>1, whereas the average value of the NI reached 2.67, which exerted adverse effects on the survival and growth of environmental organisms. In addition, the types and abundance distribution characteristics of microplastics in the interstitial waters of mangrove restoration wetlands were explored. The abundance of microplastics in the interstitial waters of the entire study area was 306.7–553.3 L-1. Moreover, different planting densities of mangroves could substantially affect the abundance distribution of microplastics, and the maximum value appeared when the planting density was 0.5 × 0.5 m. Polyethylene (49 %), polypropylene (21 %) and polyethylene terephthalate (11 %) were the most common and main microplastics in interstitial water. Scanning electron microscopy/energy-dispersive X-ray spectroscopy analysis showed that interstitial water microplastics had characteristics similar to those of sediment microplastics, such as fracture, tear, sag, and material adhesion, and the surface of the interstitial water microplastics could absorb a large amount of metal elements.

ВЗАИМОСВЯЗЬ ХИМИЧЕСКОГО СОСТАВА И УРОВНЯ ЗАГРЯЗНЕННОСТИ РЕЧНЫХ ВОД И ДОННЫХ ОТЛОЖЕНИЙ РЕК БАССЕЙНА СЕВЕРСКОГО ДОНЦА (В ПРЕДЕЛАХ РОСТОВСКОЙ ОБЛАСТИ)

The article considers the chemical composition features and pollution levels of river waters and sediments in the Seversky Donets River basin. The river waters pollution degree has been assessed using the specific combinatorial index of water pollution, and the river sediments pollution level has been evaluated using the conventional total pollution index and the integral contamination index of river sediments proposed by the authors. In order to compare the chemical compositions of the studied media we have used the concentration coefficients of elements in river waters and sediments based on the corresponding clarks. The physical and chemical features of the elements which contents differ significantly in the studied media have been analyzed in detail: namely manganese, copper, nickel, and lead. Physical and geographical and other factors that influence the distribution of elements within the river water – river sediments system in the study area have also been considered. It has been revealed that the level river sediments pollution in the Seversky Donets River basin is determined by elevated contents of nickel and lead. These elements are transferred mainly in a suspended form. It is demonstrated that the river waters pollution level depends on a number of macro- and microcomponents, and manganese and copper compounds make a significant contribution. It is concluded that the discrepancy between the levels of river sediments contamination and the river water pollution in the Seversky Donets River basin is mainly caused by the self-purification processes in river sediments.

Pollution level and health risk assessment of the total petroleum hydrocarbon in marine environment and aquatic products: a case of China.

To evaluate the pollution level and health risk of total petroleum hydrocarbon (TPH), seawater, sediments, and aquatic organisms were sampled from the southern sea area of Zhejiang Province (Yangtze River Delta, China) between 2017 and 2019. TPH was widely present in the aquatic environment and products, and its concentration was highly variable. The average value of pollution index (PI) exceeded 1 from 2017 to 2018, and 45.46-69.19% of seawater samples and 56.87-50.00% of sediment samples were polluted. The results showed significant differences in the TPH concentration in various species of aquatic organisms. The average TPH value in aquatic organisms could be ranked in the order as follows: bivalve > shrimp > crab > fish, further reflecting that the ability to accumulate and metabolize TPH existed differently among aquatic organisms within the same pond aquaculture environment. It was relatively safe to eat aquatic products since the exposure risk index was found to be far below the threshold value in this study. Therefore, it would be prudent to undertake regular monitoring of TPH to ensure effective ecosystem functioning and seafood safety in the southern Zhejiang ocean.

Influence of Source Apportionment of PAHs Occurrence in Aquatic Suspended Particulate Matter at a Typical Post-Industrial City: A Case Study of Freiberger Mulde River

Polycyclic aromatic hydrocarbons (PAHs) have received extensive attention because of their widespread presence in various environmental media and their high environmental toxicity. Thus, figuring out the long-term variances of their occurrence and driving force in the environment is helpful for environmental pollution control. This study investigates the concentration levels, spatial variance, and source apportionment of PAHs in suspended particulate matter of Freiberger Mulde river, Germany. Results show that the concentrations of the 16 priority PAHs suggested by USEPA (Σ16PAHs) were in the range of 707.0–17,243.0 μg kg−1 with a mean value of 5258.0 ± 2569.2 μg kg−1 from 2002 to 2016. The relatively high average concentrations of Σ16PAHs were found in the midstream and upstream stations of the given river (7297.5 and 6096.9 μg kg−1 in Halsbrucke and Hilbersdorf, respectively). In addition, the annual average concentration of Σ16PAHs showed an obvious decreasing pattern with time. Positive Matrix Factorization (PMF) receptor model identified three potential sources: coke ovens (7.6–23.0%), vehicle emissions (35.9–47.7%), and coal and wood combustion (34.5–47.3%). The source intensity variation and wavelet coherence analysis indicated that the use of clean energy played a key role in reducing PAHs pollution levels in suspended sediments. The risk assessment of ecosystem and human health suggested that the Σ16PAHs in the given area posed a non-negligible threat to aquatic organisms and humans. The data provided herein could assist the subsequent management of PAHs in the aquatic environment.

Distribution Dynamics of Phthalate Esters in Surface Water and Sediment of the Middle-Lower Hanjiang River, China.

Phthalate esters (PAEs) are endocrine-disrupting chemicals that pose potential risks to human health. Water and sediments are crucial carriers and storage media for the migration and transformation of PAEs. In this study, six congeners of PAEs were measured in water and sediment samples to elucidate their spatial distribution, congener profiles, and ecological risks in the middle-lower Hanjiang River during the wet and dry seasons. The concentration of the Σ6PAEs ranged from 592 to 2.75 × 103 ng/L with an average of 1.47 × 103 ng/L in surface water, while the concentration of the Σ6PAEs ranged from 1.12 × 103 to 6.61 × 103 ng/g with an average of 2.69 × 103 ng/g in sediments. In general, PAE concentrations were ranked as sediment > water, and dry season > wet season. DEHP and DBP were the dominant PAEs in the middle-lower Hanjiang River in surface water and sediments. SPSS analysis showed that dissolved organic carbon (DOC) in surface water was significantly correlated with the concentration of DBP, DEHP, and the ∑6PAEs, while organic matter (OM) was significantly correlated with the concentration of the ∑6PAEs in sediments. The concentrations of PAEs were irregularly distributed and varied significantly in surface water and sediments. Compared with other regions at home and abroad, the pollution levels of surface water and sediments in the middle-lower Hanjiang River were relatively low and not enough to have a negative impact on the local water’s ecological environment. However, the supervision of land-based discharge should still be strengthened.