Index Of Adverse Effects Research Articles

Bioavailability Assessment of Metals from the Coastal Sediments of Tropical Estuaries Based on Acid-Volatile Sulfide and Simultaneously Extracted Metals

Bioavailability assessment is important for evaluating the risks to the local biota, and the combined use of several ecological risk indices in eutrophic environments allows the best analysis of the local reality for decision-making. The relationship between acid volatile sulfide (AVS) concentrations and simultaneously extracted metals (SEM) allows us to infer the metal holding capacity of sediment, with the objective of evaluating the potential bioavailability of trace metals (Cd, Cu, Ni, Pb, and Zn) using ecological risk indices, such as the ΣSEM/AVS model and Adverse Effect Index (AEI), in surface sediments from Guanabara Bay and Sepetiba Bay, Brazil. AVS was determined using a colorimetric method and SEM with ICP-OES. In general, almost all sampling in Sepetiba Bay showed ΣSEM/AVS ratio values above 1. However, all results for the ΣSEM/AVS ratio found for the Guanabara Bay sediments were <1 for both estuaries. After normalization by organic carbon content, a possible toxicity risk for biota was found in Sepetiba Bay. However, the AEI in Guanabara Bay was above 1 for all metals in most samples, also indicating a risk to the biota.

Environmental risk of trace metals and metalloids in estuarine sediments: An example from Southampton Water, U.K.

Industrial and commercial port activities are widely recognized worldwide as an important source of pollution to proximal estuaries. In this study, we analysed geochemical and sedimentological parameters including major and trace elements, organic matter and sediment texture in surface sediments from the estuarine environment of Southampton Water, U.K. Using these data, and multivariate statistical tools [correlation, factor and cluster analysis and pollution indices such as Enrichment Factor (EF), Pollution Load Index (PLI) and the Adverse Effect Index (AEI)], we examine sedimentary trace metal and metalloid contamination, contamination sources, and potential biological impacts of the contamination present. The geochemical data, multivariate statistical analysis and pollution indices indicate that the spatial distribution of trace metals and metalloids is influenced by both sediment composition (and mixing) and anthropogenic activities. Most trace metal and metalloid concentrations are close to local geological background levels, except for Cu, Zn and Pb. The spatial distribution of these elements indicates that the Exxon oil refinery, Southampton port, local marinas and runoff from domestic and industrial activities act effectively as point sources of these elements. Pollution indices calculations highlight a degraded environment as a result of these pollutants, and further work is needed to assess the current impact of trace metals and metalloids on local ecology.

Trace-metal distribution and ecological risk assessment in sediments of a sheltered coastal area (Gulf of Gaeta, central-eastern Tyrrhenian Sea, Italy) in relation to hydrodynamic conditions

This study investigates the relationship between sediment contamination and hydrodynamic conditions in the Gaeta Gulf (Tyrrhenian Sea, Italy), an anthropogenically impacted and sheltered coastal area. The pollution levels, potential toxicity, and ecological risk of trace metals were analysed in 16 sediment sampling sites using Sediment Quality Guidelines (SQGs), the Adverse Effect Index (AEI), and the Mean ERM Quotient (m-ERM-Q). The bottom shear stress of the study area, evaluated using an annual simulation of a 3D numerical model, was used to calculate a new Sediment Mobilisation Index (SMI) that detects the coastal zones where a low probability of sediment resuspension occurs. As, Ni, and Cu concentrations exceeded the Threshold Effects Level (TEL) guideline value and AEI limit in several sampling sites, indicating their ability to produce adverse effects on biota. Moreover m-ERM-Q showed the highest values of potential ecological risk in most of the sampling sites located in the inner part of the Gulf of Gaeta. In this area, the highest SMI values were also identified, demonstrating that there is a tight relationship between the two indexes (R2 = 0.8214). The application of SMI in sheltered areas will help achieve high performance of monitoring and hazard assessment tools through obtaining predictable responses on hotspot identification.

Environmental risk of trace elements in mangrove ecosystems: An assessment of natural vs oil and urban inputs

The petrochemical industry and urban activities are widely recognized worldwide as a source of pollution to mangrove environments. They can supply pollutants such as trace elements that can modify the ecosystem structure and associated services, as well as human populations. Through geochemical data, multivariate statistical analysis and pollution indices such as the enrichment factor (EF), geo-accumulation index (Igeo), adverse effect index (AEI) and the pollution load index (PLI), we evaluated the factors that control trace element distribution, punctual sources and determined the pollution level of sediments and their potential biological impact in the mangrove ecosystem of Isla del Carmen, Mexico. The factor and cluster analysis highlighted that the distribution of trace elements is influenced by the mineralogy, texture as well as urban derived sources. The pollution indices showed values in the punctual sources from the urban area of EF > 10, Igeo > 3, AEI > 3, PLI > 1 by Cu, Zn and Pb. Finally, the results revealed that mangroves from Isla del Carmen has a major influence from urban activities and natural sources rather than oil industry and also indicate a degraded environment as a result of anthropogenic activities that could have knock-on effect for human health if polluted marine organisms derived from the urban mangroves are consumed. Capsule abstractSurface sediments show the influence of point sources on selected trace element concentrations correlated with human activities within the mangroves of Isla del Carmen, Mexico.

Relationship between enrichment, toxicity, and chemical bioavailability of heavy metals in sediments of the Cai River estuary.

This study focuses on heavy metals (HMs) (Cr, Co, Ni, Cu, Zn, and Pb) along with Al, Fe, Mn, organic carbon (TOC), and carbonates (TIC) detected in surface sediments from the River Cai-Nha Trang Bay estuarine system (South China Sea). The enrichment factors (EFAl and EFFe), Geoaccumulation Index (Igeo), Adverse Effect Index (AEI), and toxic units (TUs) were used to assess the HM enrichment and toxicity in the sediments. The selective single-step extraction procedure was applied to determine the chemical forms of HMs in order to assess their potential bioavailability. The EF and Igeo calculations suggest that sedimentary Fe, Mn, Cr, Co, Ni, and Cu are derived mainly from natural sources (EFAl and EFFe < 1.5 and Igeo < 0 at all sampling sites), while the moderate Pb enrichment (EFAl and EFFe ≥ 2 and Igeo ≥ 1 at all sampling sites) may indicate a moderate contamination. Cr, Cu, and Zn suggest low potential toxicity, while both Ni and Pb show above threshold AEI levels (AEI ≥ 1) and contribute up to 30-40% to the sum of toxic units (∑TUs) at all sampling sites. According to their comparative ability to mobilize metals from the sediments, the single extractants applied were arranged in descending order: acetic acid > ammonium oxalate >> sodium pyrophosphate. All single-step extractants mobilized substantive amounts of Pb (7-30% of total content, on average) from sediments, indicating considerable potential bioavailability. Among HMs studied, the percentage of acid-soluble Pb (23-35%) significantly exceeded the respective ranges in the sediments of other coastal regions. Pearson's correlation and PCA analyses revealed that among HMs studied, Cr, Ni, and Co enrichment is positively associated with the salinity gradient due to the accumulation of the most fine-grained Fe-rich aluminosilicate host minerals in the bay zone, while sediments in the transitional zone are mainly enriched in Cu, Zn, and Pb due to the local accumulation of metal-rich detrital heavy minerals. The percentages of bioavailable forms of most of the HMs are negatively associated with the salinity gradient due to the preferential accumulation with fluvial Fe/Mn oxyhydroxides in the frontal and transitional zones. Generally, distribution of the enrichment indices of most of the HMs is not associated or even negatively associated with the percentage of the bioavailable forms. The intensity of monsoonal precipitation is shown to be an essential factor in the natural enrichment of estuarine sediments with bioavailable metals. Determining the local geochemical background of HMs and Pb, in particular, is a major goal for future study.

Occurrence of heavy metals in sediment and their bioaccumulation in sentinel crab (Macrophthalmus depressus) from highly impacted coastal zone

The current study aimed to investigate the eight heavy metals (Fe, Cu, Zn, Cr, Ni, Co, Pb, and Cd) occurrence and risk assessment in the sediment and sentinel crab (Macrophthalmus depressus) from the mangrove and coastal environment of industrialized and mega city Karachi, Pakistan. The sediment analyzed for physiochemical properties (grain size composition, organic matter, and heavy metals), that presented significant variability (p < 0.05) among the selected sites. The environmental health and eco-toxicological profile of the habitat determined through the enrichment factor (EF), adverse effect index (AEI) and potential ecological risk index (RI) that revealed high anthropogenic influences along the Karachi coast. All heavy metals in crab showed significant spatial differences (p < 0.001) and the strong correlation between the essential and non-essential metals. Sediment-biota accumulation factor (SBAF) suggested active bio-accumulation (>1.0) in crabs for all metals, except Cr. Pb accumulation in crabs showed a significant increase (p < 0.05) with the exposure Pb levels in sediment, which indicated the potential of crab as a bioindicator of Pb contamination. Principal component analysis (PCA) concluded that environmental factors like seawater temperature, salinity, sediment grain size and organic matter had a significant association with different metal accumulation in crabs. The current study revealed the ecological significance of sentinel crab, M. depressus, as they endure with wide range (low to serious RI) of metal contaminated environment.

Cr in dredged marine sediments: Anthropogenic enrichment, bioavailability and potential adverse effects

This study focuses on chromium detected in 13 harbor sediments dredged across the English Channel. The total concentrations of Cr range from 5 to 61mgkg−1, which reveal no or low enrichment for 12 of the 13 samples, according the enrichment factor (EF) calculations. Sequential extraction procedure was applied to determine the mineralogical speciation of Cr, in order to assess its potential (re)mobilization to the aquatic environment. Cr is mainly associated to the residual fraction, then distributed in the oxydizable and reducible fractions. The possible relationships between the enrichment, mobility and possible biological effects (according calculation of Adverse Effect Index (AEI)) suggests possible toxicity incidence even for moderate enrichment. A link is observed with the oxydizable fraction (r=0.8 and r=0.5 respectively for EF and AEI).

Characterization of surface sediments from the Beijing-Hangzhou Grand Canal (Zaozhuang section), China: assessment of beryllium enrichment, biological effect, and mobility.

The South-to-North Water Diversion Project is one of the world's largest water diversion projects, benefiting seven million people in China. The Zaozhuang section of the Beijing-Hangzhou Grand Canal is an important part of this project. This paper investigated the enrichment, biological effect, and mobility of beryllium (Be) in surface sediments of the Zaozhuang section. Results showed that high values were found in Tai'erzhuang District, Zaozhuang city, and the areas near the inlet of the Nansihu Lake, which might have been influenced by local human activities including metallurgy, burning of fossil fuels, and transportation. Four geochemical fractions of Be were obtained: acid-soluble fraction, reducible fraction, oxidizable fraction, and residual fraction. The non-residual fractions (the sum of the first three) accounted for 72.5 ∼ 96.1% of the total amount of Be. Acid-soluble fraction might be mainly influenced by human activities, with the strongest mobility and bio-availability, accounting for 4.1 ∼ 44.7% of the total amount, with an average of 20.2%. Enrichment factor (EF) showed minor to moderate enrichment in some regions; adverse effect index (AEI) also showed that there were high levels of Be in some regions, which might have negative impacts on organisms. Generally, mobility, EF, and AEI of elements are carried out separately. But the results of this study indicated that a comprehensive assessment on the enrichment, mobility, and biological effects of Be caused by human activities is necessary in understanding the environmental risks of Be.

Characterization of harbor sediments from the English Channel: assessment of heavy metal enrichment, biological effect and mobility

For a full assessment of the environmental risk posed by dredged sediments not only the anthropogenic enrichment of contaminants, but also their mobility and biological impact should be considered. This study reports on the enrichment factor (EF), mobility, and Adverse Effect Index (AEI) of metals and metalloids in nine dredged sediments. Significant enrichment of As, Cd, Pb and Zn with respect to background values is detected, and calculated AEI values for these elements suggest that it is possible that a corresponding biological effect may be observed. Correlation coefficients also reveal a link between mobility in HCl and enrichment for Cd, Cr, Ni, Pb and Zn, however As and Cu do not display such a link, possibly suggesting that the source of contamination for these elements is less recent. Mobility and enrichment are two parameters which are often studied separately; however this paper shows that in some cases strong correlations occur.