الفهرس 
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Abstract
In the first part of this investigation was to examine the physic- chemicals characteristics and algal flora of some drainage at Minia district, while the second part was a study of cyanotoxin producing cyanobacteria species in irrigation water sources in Minia district and quantify the cyanotoxin concentrations possibly accumulated in vegetable and crop plants which are naturally irrigated with contaminated surface waters, and usually consumed by human.
I- Field monitoring
Water’s physical and chemical properties
1) Samples were obtained from four sites, these sites namely, Ibrahimia canal, El-Mohit drain, Bihdal drain and Orfaliy drain. The samples were taken between May 2022 and April 2023.
2) The water samples of this site was collected from Ibrahimia Canal.
The data clearly shows that the water temperature was high in September 2022, when it reached the highest value (32.2 oC), but decreased to the lowest value (17.9 oC) in December 2022. The pH value always changed to the alkaline side. The conductivity and total soluble salts in the site water did exhibit any regular trend during the investigation period. The content of the dissolved oxygen at this site tended to be higher in March 2023 (9.65 mgl-1)
and lower in September 2022 (1.08 mgl-1). The site’s total alkalinity decreased to its lowest level in January 2023 (12.0 mgl- 1), then peaked in September 2022 (60.0 mgl-1). Chloride reached its peak in July 22 (33.33 mgl-1), and it reached its lowest point in May 2022 (8.8 mgl-1). Nitrate levels in the water under investigation varied without a predictable pattern. However, phosphate levels typically tended to be higher in February 2023 compared to other months. Although there was no consistent pattern, silicate levels varied between the months. The values of monovalent (Na+&K+) and divalent (Ca2+&Mg2+) cations were found to be varied but within a small range in the present investigation.
3) The water samples of this site was collected from El-Mohit drain.
Monthly fluctuations affected the average water temperature at the investigation site. The highest pH value recorded was 8.22 for the September 2022 sample while the lowest one was 7.57 for February 2023 sample. Water’s conductivity and T.D.S. were discovered to be high in December 2022 but had decreased to a very low level by October 2022. Throughout the whole investigation period, low dissolved oxygen levels were frequently observed in the El-Mohit drain. The total alkalinity of site (II) was at its lowest point in December 2022 (22.0 mgl-1), and at its highest
point in September 2022 (63.3 mgl-1). The data also illustrated that the maximum value of chloride was appeared in December 2022 (54.20 mg l-1) while the minimum one was found to be 4.80 mg l-1 in April 2023. Regarding the main nutrients of algae, nitrate was measured at its highest level in September 2022 (4.67 mgl-1) and at its lowest level in May 2022 (0.06 mgl-1). However, phosphate tends to be higher in July 2022 compared to other months. Silicate concentrations, on the other hand, ranged from 2.94 gl-1 in January 2023 to 35.06 gl-1 in May 2022. Furthermore, the data demonstrate that in the current investigation, relatively high amounts of monovalent (sodium and potassium) and divalent (calcium and magnesium) cations were noticed.
4) The water samples at this site were collected from the Bihdal drain.
The water’s temperature ranged between 29.2 oC and 17.7 oC. With respect to the pH value, the water samples collected from this site were always alkaline. Significant increases of water conductivity and total dissolved salts were observed (1052 µS/cm and 673.28 mgl-1, respectively. The dissolved oxygen content went up during the summer and fell during the winter. During the study period, there were variations in the total alkalinity values. In April 2023 and November 2022, the nitrate-N value varied between 0.09 mgl-1
and 5.07 mgl-1. Different levels of phosphate were present in each sample.
Thus, the maximum contents of phosphate (1.60 mgl-1) recorded in February 2023, while the minimum content of phosphate (0.01 mg l-1) was recorded in January 2023. On the other hand, the maximum content of chloride obtained in January 2023 (47.2 mgl- 1), while the minimum one was obtained in April 2023 (12.0 mgl-1). Silicate concentrations were determined to be at their highest (59.70 µgl-1) and lowest (0.25 µgl-1) levels in June 2022 and January 2023, respectively. The monthly calcium and magnesium concentrations fluctuated in narrow range.
5) The water samples of this site was collected from Orfaliy drain. The monthly temperature of the drain water from Orfaliy peaked in July 2022 at 31.6 oC, and it fell to a minimum of 16.9 oC in December 2022. The pH was also on the alkaline side. The drain water’s conductivity and total soluble salts were found to be high in the sample taken in December 2022 and they decreased to their lowest levels in the sample taken in July. The summertime brought higher dissolved oxygen levels to the Orfaliy drain water than the wintertime brought lower levels. The total alkalinity of drain water were fluctuated seasonly. The amount of chloride reached its highest point in concentration in December 2022 (55.2 mg l-1) and its lowest
point in March 2023 (19.2 mg l-1).The nitrate value fluctuated from
0.08 mg l-1 to 5.6 mgl-1. Though the minimum phosphate levels were
0.30 mgl-1 in October 2022 and the maximum was 5.19 mgl-1 in July 2022, respectively. Silicate concentration were found to be fluctuated in an inverse manner. The largest amount of silicate-Si was measured in February 2023 (83.58 g l-1), while the lowest amount was measured in June 2022 (21.31 gl-1). With occasional monthly and seasonal changes, the concentrations of divalent (Ca+&Mg+2) and monovalent (Na+& K+) cations were consistently high.
Chlorophylls and algal diversity
6) The pigment content of the mixed phytoplankton in the water of the Ibrahimia Canal generally reached its maximum levels in the summer and its minimum levels in the winter. There were noticeable monthly variations in the diversity of the phytoplankton in Ibrahimia Canal. A close correlation was found between changes in Cyanophyceae abundances and changes in overall algal counts during the study period. Cyanophyceae, Bacillariophyceae, Chlorophyceae, and Euglenophyceae were the four algal groups identified in terms of taxon composition during the study period. In general, the phytoplankton species richness was highest in the early
summer and lowest in the winter. The Pearson correlation matrix of the sum variable measured in Ibrahimia Canal indicated that there were some negative and positive correlations between the various variables.
7) The data show that the amount of studded chlorophyll’s was less in the winter and more in the summer in El-moheit drain. Algal communities of El-moheit drain exhibit significant monthly fluctuations in both their quantitative and qualitative composition. Four algae groups, namely Bacillariophycae, Chlorophycae, Cyanophycae, Euglenophycae were recorded throughout this study. Cyanophyceae were the most dominant group in El-Moheit drain. Throughout the investigation period, 34 algal species were identified. Cyanophyceae was the most prevalent group, according to the taxonomic structure of the algal flora in the El-Mohit drain. The results showed that there were both positive and negative links between the various variables.
8) The Bihdal drain water had a high pigment content in the summer and a low pigment content in the winter.The data showed that the May 2022 sample had the highest algal species abundance (1460 x 105 taxa l-1), whereas the December 2022 sample had the lowest (117 x 105 taxa l-1). Cyanophyceae abundance changes throughout the investigation also closely correlated with changes in total algal
counts. During the period of the research, four algal groups were identified, Chlorophycae, Cyanophyceae, Bacillariophyceae, and Euglenophycae . The majority of 38 genera were identified over the study period. As a result, the score for this site shows that the Bihdal drain has a high level of phytoplankton biodiversity. The recorded data demonstrated that, while other associations were positive, the strongest negative relationships were found between biomass and conductivity, chloride, nitrate, calcium, magnesium, and sodium.
9) In comparison to the other three investigated sites throughout the study period, it was noticed that the mixed phytoplankton in Orfaliy Drain had a higher pigment concentration overall. The results of this site indicate that this site’s algal flora exhibits significant monthly changes from other investigated sites in terms of both its quantitative and qualitative composition. The data of also shows that throughout the whole study period, blue green algae dominated all other groups of algae. The highest algal species richness (22 genera) was seen in March 2023 and the lowest (3 genera) in November 2022. 42 genera were found, including 17 genera of Chlorophycae, 12 of Bacillariophycae, 11 of Cyanophycae, and 2 of Euglenophycae. The findings indicated that
there were some negative and positive correlations between the various variables and algal biomass.
II- Cyanobacterial toxins
10) Over the period of the investigation, there were significant differences in the MC concentrations (i.e., intracellular MCs) in phytoplankton samples. The average concentration of these intracellular MCs ranged from non-detectable to 93.7 µg l-1, with a descending order of summer > spring > autumn > winter. These toxin concentrations significantly correlated with the total cell density of cyanobacteria, particularly those reported as dominant species (e.g., chroococcus turgidus, Merismopedia elegans and Microcystis aeruginosa), indicating that these 3 species are the potentially MC producers in irrigation waters.
11) Results showed that except garlic, MC toxin was found to accumulate in all plants studied. Different plants had significantly different concentrations of accumulate MCs (P < 0.05). The amount of MCs accumulated in different plants had weak correlations with concentrations of extracellular & intracellular MCs detected in sources of irrigation. What is noteworthy here in the present study is the absence of MCs in garlic cloves, despite the detection of low concentrations of MCs in relevant irrigation water source (Bihdal drain).
12) Results showed that potato tubers had the highest EDI of MCs by adults (3.7 μg/ Kg /day) and children (7.4μg/ Kg /day). Contrarily, fava bean, Swiss chard, spinach, onion, and anise had low EDI values (0.16-1.17 μg/ Kg /day for children, and 0.08-0.6 μg/ Kg
/day for adults). However, these values are still higher than the WHO’s limit of 0.04 μg/Kg/day.