Temporal distribution of trace metals pollution load index in the Nile Delta coastal surface sediments

Biomonitoring of Heavy Metal Toxicity in Freshwater Canals in Egypt Using Creeping Water Bugs (Ilyocoris cimicoides): Oxidative Stress, Histopathological, and Ultrastructural Investigations

The abundance of metal pollutants in freshwater habitats poses serious threats to the survival and biodiversity of aquatic organisms and human beings. This study intends for the first time to assess the pernicious influences of heavy metals in Al Marioteya canal freshwater in Egypt, compared to Al Mansoureya canal as a reference site utilizing the creeping water bug (Ilyocoris cimicoides) as an ecotoxicological model. The elemental analysis of the water showed a significantly higher incidence of heavy metals, including cadmium (Cd), cobalt (Co), chromium (Cr), nickel (Ni), and lead (Pb), in addition to the calcium (Ca) element than the World Health Organization's (WHO) permitted levels. The Ca element was measured in the water samples to determine whether exposure to heavy metals-induced oxidative stress engendered Ca deregulation in the midgut tissues of the creeping water bug. Remarkably, increased levels of these heavy metals were linked to an increase in chemical oxygen demand (COD) at the polluted site. Notably, the accumulation of these heavy metals in the midgut tissues resulted in a substantial reduction in antioxidant parameters, including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and ascorbate peroxidase (APOX), along with a marked rise in malondialdehyde (MDA), cytochrome P450, and protein carbonyl levels. These results clearly indicate a noticeable disturbance in the antioxidant defense system due to uncontrollable reactive oxygen species (ROS). Notably, the results demonstrated that oxidative stress caused disturbances in Ca levels in the midgut tissue of I. cimicoides from polluted sites. Furthermore, the comet and flow cytometry analyses showed considerable proliferations of comet cells and apoptotic cells in midgut tissues, respectively, exhibiting prominent correlations, with pathophysiological deregulation. Interestingly, histopathological and ultrastructural examinations exposed noticeable anomalies in the midgut, Malpighian tubules, and ovarioles of I. cimicoides, emphasizing our findings. Overall, our findings emphasize the potential use of I. cimicoides as a bioindicator of heavy metal pollution in freshwater to improve sustainable water management in Egypt.

Ecological risk assessment of metal pollution in the surface sediments of delta region, Egypt

The surface sediments from eleven sectors perpendicular to the Egyptian Mediterranean Sea coast, along the delta region, have been assessed. These sectors cover areas of Eastern Harbour, Abu Qir Bay, Rosetta, Abo Khashaba, Burullus, Baltim, Damietta, and Manzala. The assessment process is based on determining the eight metals' (Fe, Cu, Zn, Mn, Ni, Co, Pb, and Cd) content, followed by applying different pollution and ecological risk indices such as enrichment factor (EF), geoaccumulation factor (Igeo), contamination factor (CF), Pollution Load Index (PLI), degree of contamination (Cdeg.), Nemerow Integrated Pollution Index (NIPI), and Potential Ecological Risk Index (PERI). The results indicate the average concentrations of metals (μg/g) were Fe (18,000), Mn (213), Zn (120), Ni (26), Co (13), Cu (12), Pb (10), and Cd (2). The single-pollution indices reveal that most metals were depleted to metal levels, the sediments were moderately polluted with Cd and unpolluted with other metals, and the CF values confirmed that the sediments were highly polluted with Cd and low contaminated with the rest of the metals. According to the integrated pollution indices, the Eastern Harbour, Damietta, Manzalah, and Bardawil (eastern Inlet) are the most polluted sectors relative to the rest, subjected to various point sources of pollution. Drainage management system is recommended to enhance water conservation and improve fish stocks.

Ecological and health risk assessment of heavy metals in agricultural soils from northern China

Soil pollution by heavy metals can cause continuing damage to ecosystems and the human body. In this study, we collected nine fresh topsoil samples and 18 maize samples (including nine leaf samples and nine corn samples) from agricultural soils in the Baiyin mining areas. The results showed that the order of heavy metal concentrations (mg/kg) in agricultural soils was as follows: Zn (377.40) > Pb (125.06) > Cu (75.06) > Ni (28.29) > Cd (5.46) > Hg (0.37). Cd, Cu, Zn, and Pb exceeded the Chinese risk limit for agricultural soil pollution. The average the pollution load index (4.39) was greater than 3, indicating a heavy contamination level. The element that contributed the most to contamination and high ecological risk in soil was Cd. Principal component analysis (PCA) and Pearson's correlation analysis indicated that the sources of Ni, Cd, Cu, and Zn in the soil were primarily mixed, involving both industrial and agricultural activities, whereas the sources of Hg and Pb included both industrial and transportation activities. Adults and children are not likely to experience non-carcinogenic impacts from the soil in this region. Nonetheless, it was important to be aware of the elevated cancer risk presented by Cd, Pb, and especially Ni. The exceedance rates of Cd and Pb in corn were 66.67% and 33.3%, respectively. The results of this research provide data to improve soil protection, human health monitoring, and crop management in the Baiyin district.

Application of Monte Carlo simulation for carcinogenic and non-carcinogenic risks assessment through multi-exposure pathways of heavy metals of river water and sediment, India

Heavy metal contamination has severe detrimental impacts on the entire river ecosystem's quality and causes potential risks to human health. An integrated approach comprising deterministic and probabilistic (Monte Carlo simulation) models with sensitivity analysis was adopted to determine heavy metals' chronic daily intake (CDI) and their associated health risks from the riverine ecosystem. Both carcinogenic and non-carcinogenic risks of water and sediment were estimated through multi-exposure pathways. The analytical results indicated that the concentration patterns of heavy metals in sediment (Fe > Mn > Sr > Zn > Cr > Cu > Cd) were slightly different and higher than in water (Fe > Zn > Cr > Sr > Mn > Cu > Cd). The potential carcinogenic risks of Cr and Cd in sediment (5.06E-02, 5.98E-04) were significantly (p < 0.05) higher than in water (9.08E-04, 8.97E-05). Moreover, 95th percentile values of total cancer risk (TCR) for sediment (1.80E-02, 3.37E-02) were about 22 and 143 times higher than those of water (8.10E-04, 2.36E-04) for adults and children, respectively. The analysis of non-carcinogenic risk revealed a significantly higher overall hazard index (OHI) for both sediment (adults: 1.26E+02, children: 1.11E+03) and water (adults: 3.26E+00, children: 9.85E+00) than the USEPA guidelines (OHI ≤ 1). The sensitivity analysis identified that the concentration of heavy metals was the most influencing input factor in health risk assessment. Based on the reasonable maximum exposure estimate (RME), the study will be advantageous for researchers, scientists, policymakers, and regulatory authorities to predict and manage human health risks.

Potentially Harmful Elements Associated with Dust of Mosques: Pollution Status, Sources, and Human Health Risks

Potentially harmful elements (PHEs) associated with dust generated from anthropogenic sources can be transported into mosques and deposited on the filters of the air-conditioners (AC); thereby, children and adults are exposed to such PHEs while visiting mosques. Data dealing with the assessment of PHEs pollution and its human health risk in mosques dust in Saudi Arabia are scarce. Therefore, this work aims to examine the levels and pollution status of PHEs in AC filter dust (ACFD) of mosques and their associated human health risk in three Saudi cities: Jubail, Jeddah, and Dammam metropolitan. A similar concentration pattern of PHEs is observed in three cities' mosques with noticeably higher concentrations than both global crustal and local background values for Zn, Cu, Pb, As, and Cd only. Except for Fe, Al, and Mn, the highest PHEs concentrations were found in Jeddah (1407 mg/kg), followed by Dammam (1239 mg/kg) and Jubail (1103 mg/kg). High PHEs' concentrations were also recorded in mosques located near workshops and suburban areas compared to urban areas. Based on the spatial pattern, enrichment factor, geo-accumulation index, pollution load index, and ecological risk values, Jubail, Jeddah, and Dammam have shown moderate pollution levels of Cd, As, Pb, and Zn. On the other hand, Cu. Zn, Cu, Cr, Pb, Ni, As, and Cd had degrees of enrichment levels that varied from significantly enriched to extremely highly enriched in the ACFD of the three cities. Heavy pollution is found in Jubail, which posed a higher potential ecological risk than in Jeddah and Dammam. Cd presents the highest ecological risk factors (ER) in the three cities. Carcinogenic and non-carcinogenic risks for children and adults follow the order: Jeddah > Dammam > Jubail, and the ingestion pathway was the main route for exposure. Carcinogenic and con-carcinogenic risks in the mosques of the various studied cities were generally within the acceptable range.

Morphological characterization, hazardous metal contamination, source identification, and health risk assessment of the fine road dust from Dachang mining area, China

Dachang mining area in China is known as "paradise for mineralogists" due to its most reserves of Sn, Sb, Pb, and Zn non-ferrous metal resources; thus, its evaluation for heavy metal assessment and consequent health risk is unavoidable. Sixty road dust samples were collected from study area to explore pollution level, ecological, and health risks from heavy metals and were analyzed by an inductively coupled plasma optical emission spectrometer and atomic fluorescence spectrometer. The results showed that average concentration of all the heavy metals in road dust in both mining and residential areas were remarkable higher than its corresponding background values, the former being more severe, except for Cr and Co. The morphological investigation showed that most of the particles were much less than 100 μm illustrating fine part of the road dust samples. Based on integrated pollution indices, Cd, Sb, As, Zn, and Pb were extremely contaminated and exceeded hundred times of the maximum risk value. The health risk assessment revealed substantially higher carcinogenic and non-carcinogenic risks to children and adult. Highest non-carcinogenic risk resulted from arsenic in mining and residential area with HQ_ing of 644.56 and 267.94 respectively (standard HQ ≥ 1) while carcinogenic risk to children (1.94E + 00) which greatly exceeded from the threshold value of (1.0E-4). Sb, Cd, and Pb also posed carcinogenic and non-carcinogenic risk in road dust which is caused by excessive mining activities and heavy vehicle movement in the study area.

Receptor model-oriented sources and risks evaluation of metals in sediments of an industrial affected riverine system in Bangladesh

Toxic metals in river sediments may represent significant ecological concerns, although there has been limited research on the source-oriented ecological hazards of metals in sediments. Surface sediments from an industrial affected Rupsa River were utilized in this study to conduct a complete investigation of toxic metals with source-specific ecological risk assessment. The findings indicated that the average concentration of Ni, Cr, Cd, Zn, As, Cu, Mn and Pb were 50.60 ± 10.97, 53.41 ± 7.76, 3.25 ± 1.73, 147.76 ± 36.78, 6.41 ± 1.85, 59.78 ± 17.77, 832.43 ± 71.56 and 25.64 ± 7.98 mg/kg, respectively and Cd, Ni, Cu, Pb and Zn concentration were higher than average shale value. Based on sediment quality guidelines, the mean effective range median (ERM) quotient (1.29) and Mean probable effect level (PEL) quotient (2.18) showed medium-high contamination in sediment. Ecological indexes like toxic risk index (20.73), Nemerow integrated risk index (427.59) and potential ecological risk index (610.66) posed very high sediment pollution. The absolute principle component score-multiple linear regression (APCS-MLR) and positive matrix factorization (PMF) model indicated that Zn (64.21%), Cd (51.58%), Cu (67.32%) and Ni (58.49%) in APCS-MLR model whereas Zn (49.5%), Cd (52.7%), Cu (57.4%) and Ni (44.6%) in PMF model were derived from traffic emission, agricultural activities, industrial source and mixed sources. PMF model-based Nemerow integrated risk index (NIRI) reported that industrial emission posed considerable and high risks for 87.27% and 12.72% of sediment samples. This work will provide a model-based guidelines for identifying and assessing metal sources which would be suitable for mitigating future pollution hazards in Riverine sediments in Bangladesh.

Characterization of major and trace elements in coastal sediments along the Egyptian Mediterranean Sea

The present study was conducted to provide a comprehensive picture of marine sediment characterization in terms of geochemistry and the extent of pollution. A total of 99 surface coastal sediments were collected from coastal areas along with the Egyptian Mediterranean Sea. The samples were analyzed by neutron activation analysis (NAA) and the mass fractions in mg/kg of 39 trace elements were determined. The normalized mass fractions show significant amounts of Cl (26.4%), Sn (12%), Zr (7.3%), Hf (5.9%), Ti (4.7%), Cr (4.2%), Ca (3.4%), Si (3.1%), Sr (2.9%). The mass fractions of the rare earth elements REEs (La, Ce, Nd, Sm, Eu, Tb, Dy, Yb, and Lu) are almost double compared to literature data. Principal component analysis PCA and positive matrix factorization PMF were used to decipher the sources of pollutions. Sediment quality was quantified using different pollution indices such as enrichment factor (EF), modified pollution index (MPI), pollution load index (PLI) and the new approach to calculate total pollution index (TPI). The results of the study recognized four locations with significant pollution, namely the coastal area along Al Manzalah Lake, the Nile River estuaries at Ras Elbar and its western coastal area, at the outlet of Elbrullus Lake, and finally the Abu Qir Bay. The obtained result can serve as a geochemical background of the sediments of the study coastal area, which allows following the quality of marine sediments along with the Egyptian Mediterranean Sea.

Assessing Heavy Metal Contamination Risk in Soil and Water in the Core Water Source Area of the Middle Route of the South-to-North Water Diversion Project, China

The Middle Route Project of China’s South-to-North Water Diversion Project (SNWDP) is a national-level water source protection zone and the ecological safety of its water quality and surrounding soil is of great significance. In this study, heavy metals in the surface water and topsoil in the core water source area were quantitatively analyzed using a geographic information system (GIS) and geostatistical techniques combined with environmental pollution and ecological risk assessment models to determine their environmental contamination levels, ecological risk levels, and spatial distribution patterns. Cd was identified as an essential factor responsible for the overall slight heavy metal pollution in the topsoil layer. Heavy metal contamination in surface water was primarily driven by alert-level concentrations of Hg and was consistently distributed in areas with high concentrations of Hg in the topsoil. Applying the potential ecological risk index (RI) revealed two key results. First, surface water showed no ecological risk. The concentrations of heavy metals in surface water met the goals set by relevant authorities in China. Second, overall, the topsoil was at low ecological risk, with a spatial pattern primarily influenced by Cd and Hg. Some heavy metals might have similar pollution sources and originate from human activities such as industrial activities, mining and smelting, and pesticide and chemical fertilizer applications. The study is important for improving the soil and water ecology in the reservoir area and ensuring the northward diversion of high-quality water. In addition, it provides a sound basis for making decisions about local heavy-metal remediation and treatment projects.