Quality Indicators and Possible Ecological Risks of Heavy Metals in the Sediments of three Semi-closed East Mediterranean Gulfs

Geochemical evaluation, ecological and human health risk assessment of potentially toxic elements in urban soil, Southern India

Roadside soil contamination is mostly caused by human-caused pollutant deposition. PTEs are among the many substances that are harmful for both humans and the environment. PTE concentrations in roadside soil in Chennai, southern India, have been determined in this study. To evaluate the seriousness of the threats, more environmental and geochemical indices have been applied. 83 soil samples have been obtained from the study regions and focusing on important roads. Elemental analysis has been analyzed with ED-XRF and sieve-filtered samples focused on PTEs such as arsenic, barium, cobalt, chromium, copper, iron, potassium, nickel, lead, thorium, titanium, zinc, and uranium. Significant metallic variations have been found in soil samples around roads by the investigation. The elements this study examined section ascending in the following sequence: Fe > Ti > Zn > Cr > Pb > Cu > Ni > Th > As > U > K. In the research area, the CD classification denotes high contamination, whereas the CF indices show mild to significant pollution. PLI indicates moderate to high pollution, whereas EF suggests excessive enrichment. Igeo demonstrates a range from uncontaminated to highly contaminated. PERI showed high levels in the northern study region, whereas GUFI shows several hot spots indicating moderate to severe pollution. The Hazard Index (HI) values for all metals were less than one, demonstrating the absence of non-carcinogenic risks for both adults and children. Multivariate data show natural and anthropogenic PTEs in roadside soil. In addition, a soil quality monitoring system is needed to mitigate continual contamination risks.

Ecological and environmental risks of heavy metals in sediments in Dingzi Bay, South Yellow Sea

As a special geographical location between rivers and oceans, coastal estuaries always face severe heavy metal contaminations, especially in semi-closed bay. In this study, the spatial distribution, chemical fraction, ecological risks, and potential sources of heavy metals (Pb, Cr, Cu, As, Cd, Zn, and Ni) in surface sediments and sediment cores were investigated in Dingzi Bay, Shandong Peninsula. The I_geo values and modified potential ecological risk index (MRI) indicated that Cd and As presented high environmental risks in the surface and sediment cores. The high concentration sites were mainly located in the middle and the mouth of the Dingzi Bay. The source identification indicated that most heavy metals in surface sediments originated from shipping and aquaculture, while As and Ni from industrial pollution. The correlation coefficients showed that high proportion of fine particle, TN, TOC, TP, and AVS in surface sediments could significantly elevate the bioavailability of most heavy metals.

Combining single and complex indices of pollution with grain size trend analysis of surficial sediments in Edremit Gulf, western Turkey

Pollution risk assessment of heavy metals (Pb, Cr, Cu, Ni, Zn, As) in sediment samples from 68 locations in the Gulf of Edremit, western Turkey, was performed using single and complex indices of pollution assessment approaches. The pollution indices used in the sediment analyses included pollution load index, contamination factor, contamination degree for individual metals, geoaccumulation index (Igeo), enrichment factors, toxic risk index, modified pollution index, frequency of adverse biological effects (TEL-PEL), percent incidence of biological effects (ERL-ERM), and total risk quotients. Results indicated a low degree of contamination for the entire surveyed area except moderate contamination factor for arsenic using single indices. Enrichment factors and geoaccumulation indices indicated moderate to significant enrichment and uncontaminated to moderately contaminated both for arsenic (As) and lead (Pb), respectively. According to the results of ecological risk assessment based on TELs and PELs, the adverse biological effects of heavy metals on aquatic organisms; are for As, Cr, Ni frequently, Cu and Pb occasionally, and Zn rare. The toxic risk index values displayed low to considerably toxic risk for the entire Gulf and calculated toxic risk index results showed that arsenic accounted for most of the entire sediment toxicity. Transport patterns of sediment grain size trend analyses were correlated with the results of pollution assessment models. Transport trends are compatible with the sources of lithogenic, anthropogenic, mining activities and wastewater treatment/geothermal originated arsenic.

Analysis of Spatial Variability of River Bottom Sediment Pollution with Heavy Metals and Assessment of Potential Ecological Hazard for the Warta River, Poland

Pollution of river bottom sediments with heavy metals (HMs) has emerged as a main environmental issue related to intensive anthropopressure on the water environment. In this context, the risk of harmful effects of the HMs presence in the bottom sediments of the Warta River, the third longest river in Poland, has been assessed. The concentrations of Cr, Ni, Cu, Zn, Cd, and Pb in the river bottom sediments collected at 24 sample collection stations along the whole river length have been measured and analyzed. Moreover, in the GIS environment, a method predicting variation of HMs concentrations along the whole river length, not at particular sites, has been proposed. Analysis of the Warta River bottom sediment pollution with heavy metals in terms of the indices: the Geoaccumulation Index (Igeo), Enrichment Factor (EF), Pollution Load Index (PLI), and Metal Pollution Index (MPI), has proved that, in 2016, the pollution was heavier than in 2017. Assessment of the potential toxic effects of HMs accumulated in bottom sediments, made on the basis of Threshold Effect Concentration (TEC), Midpoint Effect Concentration (MEC), and Probable Effect Concentration (PEC) values, and the Toxic Risk Index (TRI), has shown that the ecological hazard in 2017 was much lower. Cluster analysis revealed two main groups of sample collection stations at which bottom sediments showed similar chemical properties. Changes in classification of particular sample collection stations into the two groups analyzed over a period of two subsequent years indicated that the main impact on the concentrations of HMs could have their point sources in urbanized areas and river fluvial process.

First-Time Source Apportionment Analysis of Deposited Particulate Matter from a Moss Biomonitoring Study in Northern Greece

Moss biomonitoring is a widely used technique for monitoring the accumulation of trace elements in airborne pollution. A total of one hundred and five samples, mainly of the Hypnum cupressiforme Hedw. moss species, were collected from the Northern Greece during the 2015/2016 European ICP Vegetation (International Cooperative Program on Effects of Air Pollution on Natural Vegetation and Crops) moss survey, which also included samples from the metalipherous area of Skouries. They were analyzed by means of neutron activation analysis, and the elemental concentrations were determined. A positive matrix factorization (PMF) model was applied to the results obtained for source apportionment. According to the PMF model, five sources were identified: soil dust, aged sea salt, road dust, lignite power plants, and a Mn-rich source. The soil dust source contributed the most to almost all samples (46% of elemental concentrations, on average). Two areas with significant impact from anthropogenic activities were identified. In West Macedonia, the emissions from a lignite power plant complex located in the area have caused high concentrations of Ni, V, Cr, and Co. The second most impacted area was Skouries, where mining activities and vehicular traffic (probably related to the mining operations) led to high concentrations of Mn, Ni, V, Co, Sb, and Cr.

Data Analysis of Beach Sands’ Chemical Analysis Using Multivariate Statistical Methods and Heavy Metal Distribution Maps: The Case of Moonlight Beach Sands, Kemer, Antalya, Turkey

Multivariate statistical methods are widely used in several disciplines of fundamental sciences. In the present study, the data analysis of the chemical analysis of the sands of Moonlight Beach in the Kemer region was examined using multivariate statistical methods. This study consists of three parts. The multivariate statistical analysis tests were described in the first part, then the pollution indexes were studied in the second part. Finally, the distribution maps of the chemical analyses and pollution indexes were generated using the obtained data. The heavy metals were mostly observed in location K1, while they were sorted as follows based on their concentrations: Mg > Fe > Al > Ti > Sr > Mn > Cr > Ni > Zn > Zr > Cu > Rb. Also, strong positive correlations were found between Si, Fe, Al, K, Ti, P. According to the results of factor analysis, it was found that four factors explained 83.5% of the total variance. On the other hand, the coefficient of determination (R2) was calculated as 63.6% in the regression model. Each unit increase in the value of Ti leads to an increase of 0.022 units in the value of Si. Potential Ecological Risk Index analysis results (RI < 150) revealed that the study area had no risk. However, the locations around Moonlight Beach are under risk in terms of Enrichment Factor and Contamination Factor values. The index values of heavy metals in the anomaly maps and their densities were found to be successful; and higher densities were observed based on heavy metal anomalies.

Distribution and risk analysis of heavy metals in sediments from the Yangtze River Estuary, China

Sediments core within the Yangtze River Estuary was collected for metal and grain size analysis. The vertical distribution characteristics of eight metals along the core were investigated based on ¹³⁷Cs and ²¹⁰Pb radionuclide dating. The sediment was mainly composed of sand and silt. The metals concentrations were Al, 4.67-6.83; Fe, 2.3-3.94; Mn, 0.046-0.07; Cr, 69.5-103; Cu, 14.3-32.1; Zn, 47.3-96.7; Cd, 0.037-0.212; Pb, 13.7-23; Ni, 18.8-38.9 (mg·kg^-1, except Al, Fe, and Mn as %), respectively. Geoaccumulation indexes (I_geo) indicated that Cu, Zn, and Pb were of pollution-free level; Cd, Cr, and Ni were in a slight polluted level. Based on potential ecological risk factors (EI), Cd posed a moderate risk to the local environment. Correlation analysis showed that Fe, Al, and Mn had a close association with Cu, Zn, Pb, and Ni at p < 0.01. Clay was significantly correlated with other metals except Cr and Cd.