Distribution and Potential Availability of As, Metals and P in Sediments from a Riverine Reservoir in a Rural Mountainous Catchment (NE Portugal)

A geochemical investigation was carried out on the bottom sediments of a riverine reservoir, located in a mountainous rural region (NE Portugal), with the aim of evaluating the contents of As, metals and P and their potential availability. The elements contents were detected in the following ranges (µg g−1): As (18–64); Cr (32–128); Cu (39–93); Ni (18–80); Pb (49–160); Zn (207–334); P (1705–2681). The reducible fraction is the most significant in the retention of the elements. Based on their potential relative mobility, the detected metals could be classed as follows: Zn > As, Pb > Cu > Cr, Ni. The results on geochemical partitioning were revealed to be important when the Sediment Quality Guidelines (SQGs) were considered. Arsenic, Cr, Ni, Pb and Zn showed total contents exceeding the values of Probable Effect Level (PEL), but only As occurred in the most potentially available form; Cr and Ni can be considered relatively unavailable, since these are mainly associated with the residual phase. Locally, oxygen depletion could release P into the water column due to the higher concentrations in Fe-P and CDB-P fractions. The potential availability of As, metals and P in sediments indicates that the quality of sediments accumulated in small reservoirs should be considered in management policies.

Baseline Study of Trace Element Concentrations in Sediments of the Intertidal Zone of Amazonian Oceanic Beaches

Analyzing the presence and quantifying trace elements is of paramount importance to understand natural environmental processes and monitor the degree of anthropogenic disturbance to mitigate impacts already caused. Here, we aimed to establish a baseline of the trace elements profile and concentrations in sandy sediments of intertidal areas of three Amazonian beaches (Brazil). For each beach, sediments were collected from three different sectors (south, center, and north) and five shoreline distance levels (from the high- to the low-water mark), totalizing 15 samples per beach. The concentration of the different trace elements (Mg, Al, P, S, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Br, Rb, Sr, Y, Zr, Cd, Sn, I, Hg, and Pb) was determined by Total reflection X-ray Fluorescence spectrometry. Sediment was also characterized for its grain size, organic matter, and pH. To assess possible enrichment due to anthropogenic activities we compared trace element levels with the values for the Earth’s crust and calculated pollution indexes: geoaccumulation index (Igeo), ecological risk index (RI), contamination factor (CF), pollution load index (PLI), and sediment quality guideline (SQG), threshold effects level (TEL) and probable effects level (PEL). Individual trace metal concentrations did not vary significantly between beaches, sectors, or sample levels, evidencing a homogeneity of trace elements composition and concentrations across this environment. Igeo indicated 62.2% of the sampling stations uncontaminated, 20.0% from uncontaminated to moderately contaminated, and 4.44% (two sampling stations) strongly contaminated, the same two areas classified as high ecological risk by RI. Most of the sampling points presented low CF. Cadmium and Hg were the only elements that showed moderate to very high values of CF. According to the SQGs, 77.7 and 8.8% of the sampling points presented values above the moderate threshold effect level (SQG-TEL) and probable effect level (SQG-PEL), respectively. All points were classified as non-polluted according to the PLI. Our results show that the three beaches present safe levels of almost of the elements demonstrating the good state of preservation. Most of the indexes classified the sampling points as non-polluted, except for Cd and Hg in a few specific sampling points.

Geovisualization of Mercury Contamination in Lake St. Clair Sediments

The Laurentian Great Lakes of North America contain approximately 20% of the earth’s fresh water. Smaller lakes, rivers and channels connect the lakes to the St. Lawrence Seaway, creating an interconnected freshwater and marine ecosystem. The largest delta system in the Great Lakes is located in the northeastern portion of Lake St. Clair. This article focuses on the geovisualization of total mercury pollution from sediment samples that were collected in 1970, 1974 and 2001. To assess contamination patterns, dot maps were created and compared with surfaces that were generated using the kriging spatial interpolation technique. Bathymetry data were utilized in geovisualization procedures to develop three-dimensional representations of the contaminant surfaces. Lake St. Clair generally has higher levels of contamination in deeper parts of the lake, in the dredged shipping route through the lake and in proximity to the main outflow channels through the St. Clair delta. Mercury pollution levels were well above the Probable Effect Level in large portions of the lake in both 1970 and 1974. Lower contaminant concentrations were observed in the 2001 data. Lake-wide spatial distributions are discernable using the kriging technique; however, they are much more apparent when they are geovisualized using bathymetry data.

Geovisualization of Mercury Contamination in Lake St. Clair Sediments

The Laurentian Great Lakes of North America contain approximately 20% of the earth’s fresh water. Smaller lakes, rivers and channels connect the lakes to the St. Lawrence Seaway, creating an interconnected freshwater and marine ecosystem. The largest delta system in the Great Lakes is located in the northeastern portion of Lake St. Clair. This article focuses on the geovisualization of total mercury pollution from sediment samples that were collected in 1970, 1974 and 2001. To assess contamination patterns, dot maps were created and compared with surfaces that were generated using the kriging spatial interpolation technique. Bathymetry data were utilized in geovisualization procedures to develop three-dimensional representations of the contaminant surfaces. Lake St. Clair generally has higher levels of contamination in deeper parts of the lake, in the dredged shipping route through the lake and in proximity to the main outflow channels through the St. Clair delta. Mercury pollution levels were well above the Probable Effect Level in large portions of the lake in both 1970 and 1974. Lower contaminant concentrations were observed in the 2001 data. Lake-wide spatial distributions are discernable using the kriging technique; however, they are much more apparent when they are geovisualized using bathymetry data.

Ecosystem health assessment of three inland water bodies in South-west, Nigeria based on fish diversity, pollution status, ecological and health risk indices

This study was conducted to determine the health status of three water bodies (Badagry Creek, Ologe Lagoon and River Owo) because of the large amount of effluent they receive from industries around Lagos as well as the services they provide to sustain the large human population in an emerging mega city like Lagos. Water, sediment and fish samples were collected monthly from the three water bodies between January and December, 2018. Standard methods were used for the analysis of physico-chemical parameters, heavy metals, length-weight relationship, condition factor, fish diversity indices, sediment pollution indices, ecotoxicology of heavy metals in sediment and potential ecological risks as well as health risk assessment of heavy metals. The geoaccumulation index (Igeo) of heavy metals in sediments of the sampling sites ranged from − 12.14 to -0.38. The mean quotients using the probable effect level (m-PEL-Q) are 3.91 x10-4, 4.77 x10-4 and 7.87 x10-4 for Ologe Lagoon, Badagry Creek and River Owo respectively. The trend was the same with mean quotients using effect range-median (m-ERM-Q). The estimated daily intake (EDI) ranged from 0.00 mgkg-1day-1 in Pb from River Owo to 1.15 x10-3 mgkg-1day-1 in Fe still from River Owo. The range of values of the target hazard quotient (THQ) of the metals in Badagry Creek, River Owo and Ologe Lagoon are 1.23x10-4–1.65x10-2, 0.00–1.64x10-2 and 5.76x10-5–1.65x10-2 respectively. The study showed that the three aquatic ecosystems are healthy but require regular monitoring to promptly detect sudden changes in their health status.

Assessment of element concentrations in surface sediment samples from Sığacık Bay (eastern Aegean)

Concentrations of Al, Fe, As, Co, Cr, Cu, Mn, Ni, Pb, Zn, Hg, and organic carbon, and grain size distribution were investigated in the surface sediments of 7 sampling stations in the Sığacık Bay (western Anatolia) in December 2016. At all of the sampling stations, the concentrations of Pb, Ni, Cr, and As were higher than the average shale values. The highest concentrations of Pb, Cu, Zn, As, and Hg were found at stations near Doğanbey Cape. The possible sources of pollution were evaluated using several parameters: the enrichment factor (Ef), contamination factor (Cf), and contamination degree (Cd). The Ef values ranged between 0.12 and 7.61 in the bay. The high Ef (>1.5) values of Pb, Cu, Ni, Co, and As were assessed to explain the influence of anthropogenic sources. Additionally, the Cf values ranged from 0.46 to 5.61, while the Cd values ranged from 11.69 to 20.45 in the study area. The Cd of the Cr and As ranged between moderate and considerable, and the highest Cd was measured at stations near Doğanbey Cape. Additionally, the pollution degrees were assessed using sediment quality guidelines (SQGs), the threshold effect level (TEL), the probable effect level (PEL), the effects range low (ERL), and the effects range median (ERM). It was demonstrated that the sediments were generally heavily polluted with Cr and Ni, and moderately with Pb and Cu, according to the numerical SQGs. The concentrations of Pb, Cr, Cu, Zn, and Ni were above the TEL, while Cr and Ni were also higher than the PEL levels for all of the samples.

Assessment of the Environmental Significance of Heavy Metals Pollution in Surficial Sediments of South Brittany Waters, France: An Ecological Risk Assessment Approach

Distribution patterns of selected heavy metals content in sediments from the Bay of Quiberon and Gulf of Morbihan were studied to understand the current heavy metals contamination due to urbanization and mariculture activities in the coastal area. Therefore, a survey was conducted and 196 sediments collected were characterized for heavy metals content using Inductively Coupled Plasma – Mass Spectrometry (ICP–MS) after mix acid digestion process. The distribution maps of the concentrations of the heavy metals studied were produced as an isopleth map based on data interpolation by the ArcGIS software application. The association with the adverse effects on aquatic organisms was determined by the classification of the sediment according to the sediment quality guidelines. Therefore, two approaches were employed namely; direct comparison with Sediment Quality Guidelines (SQGs) by USEPA (United States Environmental Protection Agency) and comparison with other numerical SQGs, threshold effect level/probable effect level, and effect range low /effect range medium. In order to estimate the effect of multiple contaminations of heavy metals, the mean–ERM–quotient was calculated at each sampling point.

Metal Concentrations in Sediments of the Alinsaog River, Santa Cruz, Zambales, Central Luzon, Philippines

Background. Efforts are needed to evaluate heavy metal concentrations in aquatic sediments which serve as repositories and as sources of contamination of other habitats. Objectives. The present study assessed temporal changes in the pH, particle size and concentration of metals in sediments of a mining-affected river in Zambales, Philippines. Methods. Sediment samples were collected at different periods in four stations along the river using a modified Van Veen grab. The samples were subjected to quartering, air-drying, and sieved through a mesh of 40 mm prior to X-ray fluorescence spectroscopy analysis using Thermo Scientific Niton XL3t to determine metal concentrations. The sediment particle size was analyzed by the sieve method and soil pH by the electrode method. Results. Measured metal concentrations in the sediment were as follows: iron (Fe)> calcium (Ca)> chromium (Cr)> nickel (Ni)> manganese (Mn) with averages of 174.6 mg/g, 7.89 mg/g, 6.54 mg/g, 4.82 mg/g, and 2.75 mg/g dry matter (DM), respectively. The mean pH of riverine sediments was generally neutral, except for Station 4. In terms of particle size, silt and clay fractions increased in the upstream station but decreased in the midstream and downstream stations across the sampling periods. The flooding brought by Typhoon Koppu resulted in lowered concentrations of Fe, Mn, Cr, and Ni and an upsurge in Ca and potassium levels. Discussion. Most of the heavy metals (Fe, Ni, Cr, Mn) exceeded the probable effect level (PEL) for inorganics in sediments, suggesting that the adverse effects of these metals on the environment and aquatic organisms are expected to occur frequently. In comparison with Station 4, which was less affected by siltation, there was a sign of metal enrichment in the area. This indicates that soil erosion and runoff, which might have been triggered by vegetation loss, mineral extraction, and agricultural activities, had a significant impact on the quality of river sediments. Conclusions. The findings of the study point to the need for the formulation and implementation of appropriate regulatory measures for the protection and rehabilitation of the heavy metal-loaded river. Competing Interests. The authors declare no competing financial interests.

Assessment of the Environmental Significance of Heavy Metals Pollution in Surficial Sediments of South Brittany Waters, France: An Ecological Risk Assessment Approach

Distribution patterns of selected heavy metals content in sediments from the Bay of Quiberon and Gulf of Morbihan were studied to understand the current heavy metals contamination due to urbanization and mariculture activities in the coastal area. Therefore, a survey was conducted and 196 sediments collected were characterized for heavy metals content using Inductively Coupled Plasma – Mass Spectrometry (ICP–MS) after mix acid digestion process. The distribution maps of the concentrations of the heavy metals studied were produced as an isopleth map based on data interpolation by the ArcGIS software application. The association with the adverse effects to on aquatic organisms were was determined by the classification of the sediment according to the sediment quality guidelines. Therefore, two approaches were employed namely; direct comparison with Sediment Quality Guidelines (SQGs) by USEPA and comparison with other numerical SQGs, threshold effect level/probable effect level, and effect range low /effect range medium. In order to estimate the effect of multiple contaminations of heavy metals, the mean–ERM–quotient was calculated at each sampling points.

Effect Thresholds of Metals in Stream Sediments Based on In Situ Oligochaete Communities

Aquatic oligochaetes, comprising a large number of species showing various degrees of resistance to chemical pollution, are recognized as valuable bioindicators of sediments’ quality. In the Geneva area (Switzerland), oligochaete tools were previously tested for assessing the biological quality of stream sediments, and effect thresholds of combined metals (quotients) in sediments were defined. The aims of the present study were to update this previous work with new data acquired in different cantons of Switzerland and to establish effect thresholds on oligochaete communities for individual metals and for combined metals. The oligochaete metrics “Oligochaete index of sediment bioindication (IOBS)”, “oligochaete density” and “percentage of tubificids without hair setae” proved pertinent for assessing the effects of metals and organic matter in sediments. We established a threshold effect level (TELoligo) and probable effect level (PELoligo) for eight metals in sediments (Cr, Ni, Zn, Cu, Pb, Cd, Hg and As) as well as a probable effect level for these metals combined (mPELoligo-Q). These thresholds could be used directly to screen for alteration of in situ communities restricted to sediments and/or for establishing sediment quality standards based on a combination of different biological and ecotoxicological tools.