Alginates are one of the most important compounds of brown seaweeds. These compounds are employed in the food area, because of their important rheological properties, such as viscosity, gelling, and stabilizing features and as dietary fiber source. In this study, five species of dominant brown seaweeds were collected in the Red Sea (Padina boergesenii, Turbinaria triquetra, Hormophysa cuneiformis, Dictyota ciliolata, and Sargassum aquifolium) so as to characterize the alginate yield and its properties. The analysis demonstrated differences in the alginate yield among the seaweeds. The highest yield of alginate was recorded in the species T. triquetra (22.2 ± 0.56% DW), while the lowest content was observed in H. cuneiformis (13.3 ± 0.52% DW). The viscosity from the alginates varied greatly between the species, whereas the pH varied slightly. The alginate exhibited a moisture content between 6.4 and 13.1%, the ash content ranged between 12.3 and 20% DW, the protein reached values from 0.57 to 1.47% DW, and the lipid concentration varied from 0.3 to 3.5% DW. Thus, the phytochemical analysis demonstrated that the extracted alginates can be safely applied in the food industry. Furthermore, the alginate yield reveals the potential application of these seaweeds as a nutraceutical raw source, which can be exploited by the food industry.

The radioactivities of ^234+235U, ²³²Th, ⁴⁰K and ¹³⁷Cs were measured in the coastal sediments of the western Mediterranean Sea between Alexandria and Salloum, Egypt. The recorded activities of the natural radionuclides were within the range of those measured worldwide. The highest activities of ^234+235U and ⁴⁰K (166.5±7.7; 365.8±2.3 Bq kg^–1 dry weight) were measured at Sidi Krir station while El-Max station recorded the highest ²³²Th activity (22.7±0.6 Bq kg⁻¹ dry weight) indicating that these radionuclides may accumulate in ionic and particulate forms from the drainage systems of the fertiliser, petrochemical and paper industries and from agricultural drains and also as the drifted particulates from longshore currents and accretion processes. The lowest ^234+235U activities were recorded at Salloum and the lowest ²³²Th and ⁴⁰K activities were recorded at El-Hammam, indicating that the accretion process is more active in the eastern Mediterranean. Salloum recorded the highest activity levels for ¹³⁷Cs (7.9±0.4 Bq kg⁻¹ dry weight) showing significant increases of the artificial ¹³⁷Cs westwards that may be indicative of to the anthropogenic sources from the northern Mediterranean.

The finest sediment group (FSG) including (Ø3, Ø4 and <Ø4) and the bulk sediment samples were used to estimate the leachable forms of Fe, Mn, Zn, Cu, Ni, Pb, Co and Cd at Adabiya and El Zaitiya harbours in the Suez Bay at the northern tip of Suez Gulf using flame atomic absorption spectrophotometer (AAS). FSG was representing the essential constituents of the seafloor sediments with averages of 70.62% from the total sediments at El-Zaityia Harbour and 70.38% at Adabiya Harbour indicating the deposition under calm oceanographic conditions. Fe was the metal carrier for the different heavy metals, the average leachable forms of Fe and Zn in the FSG (50924.94; 377.61 µg/g) about two folds in the bulk sediment (27153.9; 180.47µg/g) at El Zaityia Harbour and about three folds in the FSG (43965.42; 456.94 µg/g) which more than the bulk sediments (17777.75; 134.62 µg/g) at Adabiya Harbour. In the same Matter, the averages of leachable forms of Mn, Cu, Ni and Pb in the FSG recorded about three folds (532.15; 195.38, 54.60, 145.94 µg/g) at El Zaitiya Harbour and (476.88; 109.42, 47.35, 67.11 µg/g) Adabiya Harbour than the recorded averages in the bulk sediment (182.43; 67.01, 19.01, 62.80 µg/g) at El Zaitiya Harbour (155.56, 35.14, 15.78, 20.27 µg/g) and Adabiya Harbour respectively.