Highlights - Assessment of potential bioavailable metals in estuary sediment

 - Receptor model was employed for source apportionment.

 - PROMETHEE was used to rank the sites based on contamination levels.

 - Enrichment factor based-indices are preferred for complete sediment assessment.

 Abstract 

A weak acid extraction was used to mobilize the loosely bound metals in estuary sediment samples. More than 30% of Ag, As, Ca, Cd, Co, Cu, Hg, Mn Ni, Pb and Zn were leached from the sediment showing that these metals are significantly present in the bioavailable form. PCA/APCS identified three sources of the metals, namely: lithogenic accounting for 72%, shipping related contributing 15% and traffic related representing 13% of the total load. Application of pollution index (PI) and modified pollution index (MPI) revealed that the sediment range from unpolluted to heavily polluted while ecological risk index (RI) classifies the sediment as posing low ecological risk modified ecological risk index (MRI) suggests considerable to very high ecological risk. To provide holistic insights into the ecological risks posed by metals, enrichment factor, MPI and MRI are recommended for the assessment of sediment in complex environments such as estuaries.

Potential bioavailability assessment, source apportionment and ecological risk of heavy metals in the sediment of Brisbane River Estuary, Australia

Overlying water, sediment, rhizosphere sediment and mangrove seedlings in the Futian mangrove forest were analyzed for heavy metals. The results showed that mangrove plant acidified sediment and increased organic matter contents. Except for chromium (Cr), nickel (Ni) and copper (Cu) in Aegiceras corniculatum sediment, heavy metals in all sediments were higher than in overlying water, rhizosphere sediment and mangrove root. Heavy metals in Avicennia marina sediments were higher than other sediments. The lower heavy metal biological concentration factors (BCFs) and translocation factors (TFs) indicated that mangrove plant adopted exclusion strategy. The geo-accumulation index, potential ecological risk index and risk assessment code (RAC) demonstrated that heavy metals have posed a considerable ecological risk, especially for cadmium (Cd). Heavy metals (Cr, Ni, Cu and Cd) mainly existed in the reducible fractions. These findings provide actual heavy metal accumulations in sediment-plant ecosystems in mangrove forest, being important in designing the long-term management and conservation policies for managers of mangrove forest.

Distribution, fraction, and ecological risk assesment of heavy metals in sediment-plant system in mangrove forest, South China Sea

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants that possess serious risks to human health and the environment. Forty riverbed sediments samples were collected in mangrove river bed sediments where artisanal refining of crude oil takes place in the Niger Delta of Nigeria. The concentration, occurrence, distribution, toxicity and health risk of sixteen priority PAHs (16PAHs) were analysed in the samples. Apart from Nap, Acy, BkF, InP and DbE, all the other PAHs were present in all the sampled points of the studied area with BbF and BaA recording the highest mean values. The range and mean of the total PAHs (∑16PAHs) of this study are 23.461–89.886 mg/kg and 42.607 ± 14.30 mg/kg dry weight (dw), which is classified as heavily contaminated when compared to the European classification of PAHs pollution in soil (>1.0 mg/kg). The range of the effect range factors used to assess the risk of PAHs in an ecosystem (Effect rang-low (ER-L) and Effect range-median ER-M) of this study is from 0.953 to 8.80 mg/kg. PAHs below ER-L (4.0 mg/kg) indicate no toxic effect, but values above ER-M (44.79 mg/kg) indicate toxic effects to the sediments, its resources and, ultimately, the public that consumes the resources thereof; hence, the study area falls within the contaminated category. The occurrence of the high molecular weight (HMW) PAHs (73.4%) supersedes those of the lower molecular weight (LMW) PAHs (26.6%). The diagnostic ratios and principal component analysis suggest that the main contributors of PAHS into the sediments are the combustion of biomass, fossil fuel (crude oil) and pyrogenic sources. The toxic equivalent quotient (TEQ) and mutagenic equivalent quotient (MEQ) of PAHs ranged from 2.96 to 23.26 mgTEQ/kg dw and 4.47 to 23.52 mgMEQ/kg dw, and the total mean toxic equivalency quotient (∑TEQ) (15.12 ± 8.4 mg/kg) is also greater than the safe level of 0.6 mg/kg, which indicates high toxicity potency. The mean incremental lifetime cancer risks (ILCRs) of human exposure to PAHs shows that both adults TotalILCR adults (6.15 × 10−5) and children TotalILCR children (2.48 × 10−4) can be affected by dermal contact rather than ingestion and inhalation. Based on these findings, the appropriate regulatory bodies and other organs of government in the region should enforce outright stoppage of the activities of these illegal artisans who do not have control mechanisms for loss control at the site and carry out appropriate clean-up of the area.

Toxicity and Risks Assessment of Polycyclic Aromatic Hydrocarbons in River Bed Sediments of an Artisanal Crude Oil Refining Area in the Niger Delta, Nigeria

The generation of tailings in the world today is immense, since only ounces or pounds of metals are extracted for each ton of ore processed. In 2022, it was estimated that more than 14 billion metric tons of mining tailings were produced per year in the world. Currently, many environmental problems associated with tailings management in both Chile and Peru are related to the potential contamination of soil, water, and air. In this article, the environmental impacts caused by tailings storage facility accidents where spills have occurred are analyzed, describing and characterizing: (i) the magnitude of the impacted area, (ii) identification of the sources, i.e., exposure routes, receptors, and (iii) an interpretive analysis of the physicochemical quality of the spilled material, the soil, the water, and the air with respect to local and international regulations. The case studies analyzed in this article correspond to tailings spills derived from the extraction of precious metals (Au, Ag) and heavy metals (Cu, Pb, and Zn) present in the minerals that dominate Chilean and Peruvian mining. Finally, environmental management measures are proposed aimed at mitigating the environmental impacts caused by the spill and remediation alternatives for the sites impacted.

/pdf/environmental-impact-assessment-of-mine-tailings-spill-2ah1um37.pdf

Environmental Impact Assessment of Mine Tailings Spill Considering Metallurgical Processes of Gold and Copper Mining: Case Studies in the Andean Countries of Chile and Peru

Heavy Metal Contamination of Forest Soils by Vehicular Emissions: Ecological Risks and Effects on Tree Productivity

In this study, the quality of sediment and surface water in two natural wetlands, Paca and Tragadero, in the central region of Peru was evaluated using pollution indices, including the geoaccumulation index, pollutant load index, modified pollution degree, potential ecological risk index, and site rank index, for four heavy metals. Principal component analysis was used to identify potential metal contaminant sources. The determination of Fe, Zn, Pb, and As was performed by flame atomic absorption spectrophotometry. The average concentrations of metals in the sediments of both lagoons decreased in the order Fe > Zn > Pb > As. The analysis of the contamination indices determined that As and Pb are the elements that contribute the most to environmental degradation in both wetlands. There is a strong correlation between the values of potential ecological risk and the modified degree of contamination, revealing that the Paca wetland has a moderate degree of contamination and potential ecological risk, while Tragadero presents a high degree of contamination and considerable potential ecological risk. The application of the site rank index showed that more than 50% of the sampling sites have between high and severe contamination. The principal component analysis presented 79.2% of the total variance. Finally, the results of this study are essential in order to carry out preventive actions for environmental protection in these lake ecosystems of great importance for many activities, such as bird watching.

Ecological Risk Due to Heavy Metal Contamination in Sediment and Water of Natural Wetlands with Tourist Influence in the Central Region of Peru

Determination of toxic metals in commonly consumed medicinal plants largely used in Peru by ICP-MS and their impact on human health

The heavy metal accumulation in the sediment and removal efficiency in stabilization ponds with Hydrocotyle ranunculoides filter were evaluated. Sediment and water were sampled in June, July and August 2018. The sediment sampling for each lagoon was conducted at three sites forming a composite sample. The water samples were collected in the tributary and effluent pipelines to determine the heavy metal concentration and removal efficiency by Hydrocotyle ranunculoides. The determination of heavy metals was performed with the method of atomic flame absorption spectrophotometry. The mean concentration of heavy metals in the sediment, in a descending order, was: Fe > Zn > Pb > Cu > Cd. The concentrations of these metals ranged from 998.0 to 1365.02, from 488.01 to 600.30, from 88.23 to 95.01, from 1.47 to 1.53 and from 0.01 to 0.13 mg/Kg, respectively. In the four stabilization ponds, the pollution factor values for Cd, Cu and Fe qualified as low pollution factor. While for Zn and Pb, they qualified as moderate pollution factors. The heavy metal removal rates from the water varied by metal

http://www.jeeng.net/pdf-122189-51953?filename=Heavy Metal Accumulation.pdf

Heavy Metal Accumulation in Sediment and Removal Efficiency in the Stabilization Ponds with the Hydrocotyle ranunculoides Filter

Contamination generated by dumps is an environmental problem because the soils around the dumps are used for the cultivation of agricultural products and pastures, and could constitute a threat to human health. The contamination index and ecological risk potential for heavy metals in agricultural soils surrounding the solid waste dumps in Agua de las Vírgenes (AV) and El Eden (ED) in Huancayo were evaluated. The concentration of heavy metals in the soils was measured using an inductively coupled optical emission spectrophotometer. The average concentra tion of As, Cd, Cr, Pb, Cu, Fe and Zn in the soils was 25.77, 1.03, 6.09, 112.07, 48.52, 53733.33 and 349.10 mg/ kg in AV and 14.35, 0.28, 2.85, 123.01, 57.47, 36137.50 and 414.31 mg/kg in ED respectively. The mean values of the contamination factor for As determined a very high soil contamination status at both sites. The order of mean Igeo values was As> Cd> Pb> Zn> Cu> Fe> Cr. The soils are strongly enriched with As and Cd. The highest risk index was for Cd, with a higher contribution to the overall potential risk index. The principal component analysis explained that 71% of the data set and the identified sources of heavy metals are the varied composition of wastes in general and crop irrigation with wastewater. In general, agricultural soils are characterized for a level of ecological risk that varies from high to very high. Among the measured heavy metals As, Cd and Pb pose significant health risks. Continuous monitoring of the level of contamination of soils affected by dump leachate and wastewater ir rigation is suggested.

Edith Orellana-Mendoza

Papers

Ecological Risk Due to Heavy Metal Contamination in Sediment and Water of Natural Wetlands with Tourist Influence in the Central Region of Peru

Determination of toxic metals in commonly consumed medicinal plants largely used in Peru by ICP-MS and their impact on human health

Heavy Metal Accumulation in Sediment and Removal Efficiency in the Stabilization Ponds with the Hydrocotyle ranunculoides Filter

Ecological Risk Assessment for Heavy Metals in Agricultural Soils Surrounding Dumps, Huancayo Province, Peru