A comparative study of surfactant distribution and fate (western and eastern) Egyptian Mediterranean coasts focusing on its environmental toxicity.

One of the most difficult-to-manage new contaminants constantly released into the environment is linear alkylbenzene sulphonate (LAS), an anionic surfactant. Significant volumes of LAS are received by the Mediterranean coast of Egypt. The current study is a comprehensive assessment of the environmental fate of the LAS 1505 km off the Mediterranean coast of Egypt in the fall of 2023 in order to track its geographic spread and eventual demise in the water column. Critical analysis of LAS revealed that it is vertically distributed in various ways according to sources, uses, production amounts, and salinity levels. The vertical variation of LAS can be explained by its amphiphilic structure. A significant increase in surfactant concentration (>300 µg/L) was recorded in 66% and 43% of the total samples, ranging from 301.128 to 455.36 and from 304.556 to 486.135 for the western and eastern sides along the Egyptian Mediterranean coast, respectively. Evaluation of the average acute and chronic risk quotient (RQ) along the investigated locations revealed that fish were the most susceptible to LAS in both long and short exposure periods. The presented results also indicated significant LAS toxicity to three trophic levels (RQ values > 1). LAS toxicity to marine organisms was greater in the western than in eastern coastal regions according to acute and chronic mixture risk characterization ratios (RCRmix). The three trophic levels in the study area had the following order of acute relative contribution (RC) to LAS toxicity: fish > invertebrates > algae. The ANOVA test results showed that in both the western and eastern regions, LAS varied significantly (p < 0.05) with salinity (1.04E-60 and 5.44E-42) and depth (6.02E-65 and 1.59E-47), respectively. In addition, a significant difference was observed using the ANOVA test between the eastern and western regions of the Egyptian Mediterranean coast.

Impact of land development along the western Mediterranean coast of Egypt regarding surfactant sources, interfering elements and ecotoxicity.

The effect of recent land development of the western side of the Egyptian Mediterranean coast on the fates, behaviors, interactions, and ecotoxicology of surfactant (LAS), F, Br, B, Ca, Mg, and P was studied. Samples of seawater and sediments were collected from 15 stations at different depths representing, 5 perpendicular sectors. Elevated levels of LAS were identified in seawater columns in the El-Hamam (467.3 ± 220.8 µg/L) and El-Dabaa (480.0 ± 314.1 µg/L) stations. LAS homologue in sediment was in the range of 0.013-0.024, 0.042-0.184, 0.086-0.402, and 0.025-0.058 µg/g for C10, C11, C12, and C13, respectively. Studied parameters showed mixture risk characterization ratios RCRmix > 1 for algae, invertebrates, and fish in seawater and sediments, except for P, which showed low risk (RCRmix ≤ 1) in sediment. Acute relative contribution (RC) of LAS reflected that fish were the most sensitive species (RCFish = 48.5), followed by algae (RCAlgae = 44.4) and invertebrates (RCInvert = 7.1).

Reactive sulfide dynamic models for predicting metal hazardous in sediments of two northern Egyptian Lakes.

To track pollution status and bioavailability of Cu, Zn, Cd, Pb, and Ni, the current study's acid-volatile sulfide (AVS) and simultaneously extracted metals (SEM) models were compared to previous studies in Edku and Mariut lakes prior to 8 years. Sediment samples were collected in winter and summer 2019 from the two lakes. Metal pollution is higher in the winter than in the summer, according to SEM/AVS models. Metal toxicity is reported to have increased slightly in both lakes. According to risk quotients (RQSEM-PEL and RQSEM-TEL) the two lakes are moderately polluted. The results of the Fe/AVS ratio were in the range of 6.77 to 226.87 and 2.88 to 36.38 µmol/g for Edku and Mariut lakes, respectively. This indicated that [SEM]/[AVS] ratios overestimate the availability of metals. A positive correlation was reported between total organic matter and ∑SEM (r = 0.74 and 0.39 at p < 0.05) in Mariut and Edku lakes, respectively. Multiple-year SEM-AVS studies are recommended.

Cytotoxic and antimicrobial activities of two new sesquiterpenoids from red sea brittle star Ophiocoma dentata.

Bioactive compounds were extracted from a locally available brittle star; Ophiocoma dentata, collected from the Red Sea, Egypt. Two new sesquiterpenoids; 8, 11-epoxy-9(15)-himachaladiene-4-ol (O8-ophiocomane) and, 11-epoxy-9(15)-himachaladiene-4-ol (O7-ophiocomane) were isolated and characterized using appropriate techniques. Structure elucidation was estimated via 1D NMR, 2D NMR, FT-IR and mass spectroscopy analyses. The isolated compounds were tested for cytotoxic, antibacterial and antifungal activities. Pure compounds showed a dose dependent reduction in MCF-7 cells viability with LC50 of 103.5 and 59.5 µg/ml for compounds 1 and 2 respectively compared to the chemotherapeutic drug cisplatin (47.4 µg/ml). In vivo experiments showed that O. dentate extract significantly reduced tumor progression and improved hematological parameters and liver functions of tumor-bearing mice when administered either before or after tumor cells' injection. The most remarkable antimicrobial effects of O. dentate crude extract were against Staphylococcus aureus, Vibrio damsela and Pseudomonas aeruginosa while the pure compounds showed activity against P. aeruginosa alone. Neither the crude extract nor the pure compounds have shown activity against Aeromonas hydrophila. These results indicates that O. dentata extract and newly isolated compounds have shown a promising cytotoxic, antiproliferative and antimicrobial activities that might be useful for pharmaceutical applications.

Influence of the Linear Alkylbenzene Sulfonate (LAS) on hematological and biochemical parameters of Nile Tilapia, Oreochromis niloticus.

The acute toxicity of household detergent (Ariel) on blood parameters and histology of Oreochromis niloticus was investigated using static bioassay for 96 h. Linear alkyl benzene sulfonate (LAS) is an anionic surfactant widely used in detergents and cleaners, both in industrial and household applications. LAS contaminating aquatic ecosystems as a potential toxic pollutant, was investigated in the present study for acute toxicity. The fish samples were divided into six groups, including 20 fish in each group. Normal feed was given to control group without detergents treatment. Hematological parameters (RBC count, Hb, Ht and platelets) were significantly declined, while WBC count showed a highly significant increase. Compared with the control group, significant elevation of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) was recorded in fish treated with different concentrations of detergent. Catalase (CAT), Superoxide dismutase (SOD) activities and Reduced Glutathione (GSH) concentration showed a highly significant reduction. Total proteins showed significant decrease, while total lipids, cholesterol and triglycerides significantly increased. The mean lethal concentration (LC50) for 96 h of Ariel was at concentration 10 mg/L. Relative percentage of detergent residues in fish muscles was increased with higher detergent concentrations. In conclusion, exposure to detergents resulted in great alterations in the histological structure of liver and gills.

Metals in a northern Nile Delta lake: water, suspended particulates, sediments, and biota.

Lake Edku is one of the important fishing areas in the Nile Delta. It is exposed to different quantities of serious pollutants in particular metals. To overall appraise the risk and status of metals in the lake, a comprehensive study of total concentrations of cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), and zinc (Zn) in sediments and spatial-temporal variations of these metals in the dissolved and suspended particulates, and some tissues of Tilapias niloticus, was conducted from ten sampling sites during 2016. Results showed that none of the investigated metals exceeded the limits considered as hazardous for aquatic life in water. The highest concentrations of Cd, Cu, Ni, and Zn were observed in suspended particulate matter, which may precipitate on the surface of the sediments. Potential ecological risk analysis of the majority of the investigated metals in the sediment indicated that Lake Edku posed a low ecological risk. The estimated values of all metals in tissues of Tilapia niloticus were below the international permissible limits. Moreover, the potential risk of metals to human via the consumption of Tilapia niloticus was estimated using the weekly intake levels, which was lower than the WHO's safe provisional tolerant weekly intake levels. These results prove the importance of performing measurements of contaminants in various compartments of Lake Ecosystem including sediment, biota, and suspended particulate matter for proper management.

Risk assessment and chemical fractionation of selected elements in surface sediments from Lake Qarun, Egypt using modified BCR technique.

In this study, spatial distribution and chemical fractionation were conducted to appraise the overall classification of Al, B, Cd, Cr, and Pb as well as their ecological risks in Lake Qarun sediments. Also, the other chemical components (CaCO3, TOC, SO42-, SiO32-, PO43-, F, Ca, and Mg) that represented the chemical composition of the sediments were determined. Modified BCR sequential extraction technique was used to evaluate the four (acid soluble, reducible, oxidizable and residual) fractions of the surface sediments. The association of Cd was found the highest with acid-soluble fraction (12.16-77.42%), while, Al (89.92-96.83%), B (42.32-93.93%), Cr (86.35-97.42%) and Pb (31.98-86.26%) were reside in residual phase. The degree of surface sediment contamination was computed by risk assessment code (RAC), individual contamination factor (ICF) and Global contamination factor (GCF). Risk assessment code classification showed that the relative amounts of easily dissolved phase of the investigated elements in the sediments are in the order of: Cd > Pb > B > Cr > Al. As a result, Cd had the highest risk to Lake Qarun. This study is a first approach of chemical fractionation of Al, B, Cd, Cr, and Pb in one of the most ecologically important Protectorates declared in the framework of Law 102 of year 1983. Information of this study constitutes a baseline of elements fractionation in Lake Qarun sediments and should be used as a reference for future studies on the changes of labile and residual elements fractions over time.

Fractionation profile and mobility pattern of metals in sediments from the Mediterranean Coast, Libya.

A five-step sequential extraction technique, following Tessier's protocol, has been applied to determine the chemical association of Cd, Cu, Fe, Pb, and Zn with major sedimentary phases (exchangeable, carbonate, manganese and iron oxides, organic and residual fraction) in surface sediments from 14 stations off the Libyan Mediterranean coast. This study is a first approach of chemical fractionation of these metals in one of the most economically important area of the Libyan coastline in Mediterranean Sea. The total metal content was also determined. The total concentration of metals ranged from 5-10.5 mg/kg for Cd, 9.1-22.7 mg/kg for Cu, 141.8-1056.8 mg/kg for Fe, 18.9-56.9 mg/kg for Pb, and 11.6-30.5 mg/kg for Zn. The results of the partitioning study showed that the residual form was the dominant fraction of the selected metals among most of the studied locations. The degree of surface sediment contamination was computed for risk assessment code (RAC), individual contamination factor (ICF), and Global contamination factor (GCF). Risk assessment code classification showed that the relative amounts of easily dissolved phase of trace metals in the sediments are in the order of Pb>Zn>Cd>Cu>Fe. The results of ICF and GCF showed that Sirt and Abu Kammashand had higher GCF than other sites indicating higher environmental risk. In terms of ICF value, a decrease order in environmental risk by trace metals was Pb>Zn>Cu>Cd>Fe. Therefore, Pb had highest risk to water body.

Detection of persistent OCPs and PCBs congeners in the near-shore coastal waters of Alexandria, Egypt.

The residues of 19 EPA-organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were determined in water samples collected from the near-shore surface water of Alexandria coast, Egypt, using gas chomatograph-electron capture detector (GC-ECD) and gas chromatograph-mass spectometer (GC-MS). Higher concentrations of hexachlorocyclohexane (HCH)s, TC, and 2,2-bis (p-chlorophenyl)-1,1,1-trichloroethane (DDT)s with 1.36, 0.556, and 36.97 ngl(-1) were recorded, respectively, with a maximum of 165.46 ngl(-1) of PCBs during June 2014, which was clearly affected by higher sewage activities during summer season. Among DDTs metabolites, p,p-DDT was the most dominant with a maximum of 36.31 ngl(-1) recorded at El-Montazah station during June 2014.

Metals bioavailability in surface sediments off Nile delta, Egypt: Application of acid leachable metals and sequential extraction techniques.

Surface sediments from Nile Delta coast were analyzed for texture, CaCO3, organic matter, fractionation, and acid leachable metals (Cr, Fe, Mn, Ni, Pb, and Zn). The distribution pattern of acid leachable heavy metals in the sediment follows the sequence: Fe>Mn>Pb>Zn>Ni>Cr. All the acid leachable metals didn't exceed the sediment quality guidelines values (effects range low (ERL) and effects range medium (ERM)) and therefore doesn't represent a danger to marine organisms. The correlation of acid leachable Fe, Ni, and Mn indicates a similarity in the association of metals of similar origin. The negative correlation of sand with acid leachable Cr, Fe, Ni, Pb, and Zn indicates that these elements can be easily released by ion exchange processes due to the electrostatic interaction of trace metals as they are weakly bound and is bioavailable to the liquid phase. The acid leachable Cr, Pb, and Zn indicate their association with the CaCO3, while acid leachable Fe, Mn, and Ni are hardly combined with carbonates. All the contents of acid leachable metals are negatively correlated or uncorrelated with OM, which indicates that the studied heavy metals are hardly combined with OM. The results of the partitioning study showed that the residual form was the dominant fraction of the Cr, Fe, and Ni among most of the studied locations. Among the non-lithogenic fractions, the Fe-Mn oxy-hydroxide is the main scavenger for all metals. In terms of risk assessment code (RAC) value, a decrease order in environmental risk by heavy metals was Pb>Mn>Zn>Ni>Cr>Fe. Although the results of the two techniques were not consistent with each other in terms of predicting the metals bioavailability, a combination of total metal concentrations, acid leachable metals, and sequential extraction analysis is necessary to acquire the comprehensive information on the baseline, anthropogenic input, and bioavailability of heavy metals.

Assessment of heavy metals pollution using AVS-SEM and fractionation techniques in Edku Lagoon sediments, Mediterranean Sea, Egypt.

A method is presented to evaluate the fractionation of metals (Fe, Zn, Cu, Pb, Cd and Ni), acid volatile sulfide (AVS) and simultaneously extracted metals (SEM) in Edku lagoon sediments. Thirteen sediment samples were collected from the study area in the period of 2010-2011 to assess the potential bioavailability and toxicity of the selected metals. According to classification of the Interim Sediment Quality Quidelines (ISQG), five stations near the drains exhibited 10% toxic probability. The high AVS and low ∑SEM ranges in Summer were identified as 6-138 and 0.86-3.3 µmol g(-1) dry wet, respectively which are referring to the low mobility of heavy metals in this season and vice versa for winter (2.5-23.9 and 1.16-3.82 µmol g(-1) dry wet, respectively). According to the evaluation of USEPA, all sediment samples showed ∑SEM/AVS < 1 and ΣSEM-AVS < 0 and this indicates that Edku lagoon sediments didn't cause any adverse effects. Meanwhile, the calculations of the global contamination factor (GCF) and the individual contamination factors (ICF) using fractionation technique gave values of 111.644 and 84.555 in El Bosily drain and station 1 near the cages of fish farm, respectively due to possible contamination. Interestingly, the collected data refer that the mobility and bioavailability of heavy metals in Edku lagoon sediments posed a low risk of adverse biological effects due to cadmium, copper, lead, nickel and zinc in all evaluated stations.

Spatial variation of acid-volatile sulfide and simultaneously extracted metals in Egyptian Mediterranean Sea lagoon sediments.

In risk assessment of aquatic sediments, the immobilizing effect of acid-volatile sulfide (AVS) on trace metals is a principal control on availability and associated toxicity of metals to aquatic biota, which reduces metal bioavailability and toxicity by binding and immobilizing metals as insoluble sulfides. Spatial variation pattern of AVS, simultaneously extracted metals (SEM), and sediment characteristics were studied for the first time in surface sediment samples (0-20 cm) from 43 locations in Egyptian northern delta lagoons (Manzalah, Burullus, and Maryut) as predictors of the bioavailability of some divalent metals (Cu, Zn, Cd, Pb, and Ni) in sediments as well as indicators of metal toxicity in anaerobic sediments. The results indicated that the ∑SEM (Cu + Zn + Cd + Pb + Ni) values in sediments of lagoon Burullus had higher concentrations than those of Maryut and Manzalah. In contrast, AVS concentrations were considerably higher in lagoons Manzalah and Maryut and seemed to be consistent with the increase in organic matter than lagoon Burullus. Generally, the average concentrations of the SEM in all lagoons were in the order of Zn > Cu > Ni > Pb > Cd. The ratios of ∑SEM/AVS were less than 1 at all the sampling stations except at one station in lagoon Maryut as well as four stations located in lagoon Burullus (∑SEM/AVS > 1), which suggests that the metals have toxicity potential in these sediments. Therefore, SEM concentrations probably are better indicators of the metal bioavailability in sediments than the conventional total metal concentrations.