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Abstract Summary 81 Summary Microcystins (MCs) are a group of biologically active monocyclic hepatopancreatic peptides produced by some bloom-forming cyanobacteria in water. They are well known for their toxic effects on aquatic organisms and humans. Also, they have attracted much attention for their acute lethal toxicity to human and animals. In human, MCs are mainly considered as hepatotoxins causing high incidence of liver cancer in populations’ dependent upon MC-contaminated drinking water, cause death in human when exposed to them through hemodialysis. In animals, MCs cause deaths in wild animals and cattle however; cattle having survived acute intoxication may develop hepatic photosensitization. Plants, vegetables and food crops irrigated with microcystin contaminated water are negatively affected including their quality with a reduction in their yields. Plants in general are capable of accumulating MCs in their tissues so that consuming these contaminated crop and plants are considered a risk factor for human health. Additionally, MCs cause illness and even death in aquatic life. It was reported that MCs have been accumulated in various aquatic organisms which are further consumed by human. The harmful cyanobacterial blooms in natural water have become an increasing environmental problem all over the world due to increasing the discharge of wastewater containing nitrogen and phosphorus to rivers and lakes. And these toxic blooms are dominant in eutrophic lakes, ponds, lagoons, streams and reservoirs worldwide. Many countries in the world suffer from the problem of intensive cyanobacterial blooms in surface water. Discharge of urban, agricultural and industrial wastes into the water sources worldwide lead to eutrophication that cause increase in the cyanobacterial blooms. As well as excessive agricultural use of manure and fertilizers cause eutrophication of the surface water bodies leading to harmful algal blooms development. MC-LR has been detected in surface water and included in surface water environmental quality standards and drinking water hygiene standards in different countries to ensure the drinking water safety. Therefore, regular surveillance of microcystin in the intake source water should be kept on providing safe drinking water to prevent exposure of consumers to cyanobacterial metabolites. As well as the present study aimed to present trials for efficient removal of the biological toxin produced by cyanobacteria and preserves the human and livestock health using cheap available adsorbent materials. In this study the water samples were collected from 18 sampling locations representing three water types (river, irrigation and wastewater) in Sohag and Assiut Governorates. A total of 72 water samples were collected including river water samples (20), irrigation water samples (20) and wastewater samples (32). After extraction of the collected water samples, the microcystins were quantified using ultra-high performance liquid chromatography (UPLC). After detection of microcystins in the collected samples they were removed from the real sample that was previously quantified, using cheap available adsorbent materials (Rice straw, Corn straw and Sawdust) and compared them with the commercially available adsorbent material (activated charcoal). Summary 82 The results obtained in this study revealed that: Physical parameters of river, irrigation and wastewater smples collected from Sohag and Assiut Governorates: The temperature of river water sampling locations was 27.2 ± 2.86 oC which was higher than the maximum permissible limit of river water (22 and 24 oC for class I (satisfactory) and class II (doubtful), respectively). Water temperature can be affected by many ambient conditions. These elements include sunlight/solar radiation, heat transfer from the atmosphere, stream confluence and turbidity. Shallow and surface waters are more easily influenced by these factors than deep water. Temperature of irrigation water was 28.8 ± 2.58 oC which was within the maximum permissible limit (40 oC). The temperature value at the sampling locations of wastewater samples was 28.62 ± 1.18 oC. The pH of river water, irrigation water and wastewater sampling locations were 7.47 ± 0.14, 7.6 ± 0.15 and 7.41 ± 0.3, respectively. PH values of irrigation water and wastewater were within the maximum permissible limits of 6.5-8.5 and 5.5- 9.5, respectively. The pH of the water is affected by increase influx of carbon dioxide which causes the increase of pH. However, it does not rule out the possibility that temperature also affects the pH. Chemical parameters of river, irrigation and wastewater collected from Sohag and Assiut Governorates: The chemical oxygen demand (COD) of the collected river water, irrigation water and wastewater samples ranged between 2.2-14.2 mg/L (8.74 ± 4.68), 1.3-107 mg/L (37.05 ± 42.48) and 2.2-126 mg/L (24.01 ± 34.16), respectively. COD values of the collected irrigation water and wastewater samples were within the acceptance limit (100 mg/L) and (6-12 mg/L), respectively. The total nitrogen (TN) values of the collected river water irrigation water and wastewater samples were 2.61 ± 1.61 mg/L, 4.70 ± 2.98 mg/L and 4.62 ± 4.94 mg/L. TN values for irrigation water and wastewater samples were within the permissible limit of 35 mg/L and 5-10 mg/L, respectively. The total phosphorus (TP) concentration of the sampled river water was variable between 0.08- 4 mg/L (1.42 ± 1.21 mg/L) and was higher than the permissible limit (0.2-0.4 mg /LP for class I and class II, respectively). The TP value of the collected irrigation water samples ranged between 0.14-2.25 mg/L (0.83 ± 0.60 mg/L). The TP values of the collected wastewater samples were ranged between 0.2-18.6 mg/L (1.92 ± 4.19 mg/L) which was higher than the permissible limit (not more than 2 mg/L) giving indication of organic contamination in these sampling locations. Summary 83 The concentration of the dissolved oxygen (DO) in the collected samples was over-range because it was higher than the maximum detection limit of the kit (10-800 μg/L). Concentration of microcystins in different water samples: Microcystins were measured in all collected river water samples, 12 (60%) of them contained microcystins concentration lower than the maximum permissible limit established by WHO, these samples were collected from Palasfora, Sohag and Elmaragha and the other 8 (40%) samples contained concentration higher than that established by WHO, these samples were collected from Almonshah and Mishta. The hazard quotient of microcystins through ingestion of river water from location SR4, Sohag Governorate was more than 1 for children indicating high potential risk to the children who drink river water from this location. Microcystins were detected in 16 (80%) of total collected irrigation water samples. The concentration of MCs was lower than the maximum permissible limit established by WHO in 8 (40%) irrigation water samples which were collected from Banga and Tema and higher than the MPL in the last 12 (60%) samples which were collected from Tema2, Sudfa and Mawqif almuealimin. Finally, MCs could be detected in the 32 collected wastewater samples, where the concentration was lower than the WHO guideline in 4 (12.5%) samples, equal to the WHO guideline in 4 (12.5%) samples and higher in 24 (75%) of the total collected wastewater samples. Removal of microcystins (MCs) The efficiency of rice straw for MCs removal from the acidified water samples reached up to 82.8 % and that for removal from the neutral water samples reached up to 75.4%. Therefore, rice straw as adsorbent material is more efficient in removal of extracellular MCs from both acidified and neutral water samples. However, the removal efficiency of MCs from acidified water samples using corn straw reached up to 73.4% and the removal capability from neutral water samples using was up to 85.8%. Concerning using of corn straw as adsorbent material for microcystins removal it is more efficient in removal of intracellular MCs from acidified water samples whereas more efficient in removal of extracellular MCs from neutral water samples. The ability of sawdust to remove MCs from acidified water samples was up to 95.4% while its capability to remove them from neutral water samples reached up to 96.4 %. Sawdust is the most effective adsorbent material in removal of total MCs from both acidified and neutral water samples. Also, it is more efficient in removal of intracellular than extracellular MCs from acidified water samples while it is more efficient in removal of extracellular MCs from neutral water samples. Summary 84 The efficiency of MCs removal from acidified water sampled using activated charcoal was up to 89.5% whereas its ability to remove them from the neutral water samples reached up to 95.9%. Activated charcoal showed high efficiency of total MCs removal from both acidified and neutral water samples. Conclusively, hence the need for major intervention, such as low-cost pretreatment of water, education of the user about the need for regular observation of the physical appearance of the water and promotion by health authorities of container hygiene to be achieved through regular brushing and sanitizing of containers to keep the vessel free of biofilm. The selected cheap adsorbent materials (rice straw, corn straw, sawdust) showed good efficiency for MCs removal from both acidified and neutral water samples. Therefore, the current study recommends the use of the selected cheap adsorbent materials (rice straw, corn straw and sawdust) to purify the water and remove the MCs as well as avoiding contamination of the environment by these left- over crops. The application of these cheap available materials achieves our goals of this study which are removal of MCs from water sources with effective, applicable and available materials in addition getting rid of these wastes which represent a source of environmental contamination. |