Research Publications

<p>The River Nile, Egypt’s main source of water, is polluted by agricul tural, industrial and municipal wastewater discharges. The paper reports a study of biological pollution of river water through bac terial and parasitological analysis, besides chemical pollution by cadmium and lead. The researchers collected water samples sea sonally from 12 sites in Greater Cairo along a year (from July 2019 to June 2020). Some sites were contaminated with total coliforms, Acanthamoeba sp., and Cryptosporidium oocysts, whereas Naegleria sp. was recorded at all sites. Although the recorded Cd concentrations were below the permissible levels in all sites, the concentration of Pb exceeded the permissible limit in some sites. In conclusion, Nile River water in Greater Cairo region is contaminated, especially with total coliforms and free living amoebae. This health threat needs to be controlled and diminished by law.</p>

<p>The paper reports an assessment of the quality of some water courses located in three Egyptian governorates by investiga tion of organochlorine and organophosphorus pesticides residues, and the distribution of macroinvertebrates. Water and sediment samples were collected from the investigated sites in Giza, Qalubeya and Gharbeya governorates. The results showed that the total beta- hexachlorocyclohexane (β-HCH) was the highest in concentration amongst other organochlor ine pesticides in both Giza and Gharbeya governorates, and the total Dichlorodiphenyltrichloroethane (DDT) concentration was the highest in Qalubeya Governorate. In the organopho sphorus pesticides group, fenitrothion and fenamiphos showed the highest concentrations in all collected samples. In addition, gastropods were the dominant macroinvertebrates, and all sensitive organisms disappeared from all studied sites during all seasons indicating a poor water quality. The investigated watercourses are highly polluted with pesticides residues which have harmful consequences for both aquatic biodiver sity and human health.</p>

<p><span style="color: rgb(34, 34, 34); font-family: Merriweather, serif; font-size: 18px;">One of the most common compounds in pesticide formulations, plastics, and papers is 4-nonylphenol (4-NP). It is contained in agricultural, industrial, and wastewater effluents, which when discharged into surface waters affect aquatic fauna. Therefore, the present study aimed to use&nbsp;</span><i style="box-sizing: inherit; color: rgb(34, 34, 34); font-family: Merriweather, serif; font-size: 18px;">Biomphalaria alexandrina</i><span style="color: rgb(34, 34, 34); font-family: Merriweather, serif; font-size: 18px;">&nbsp;snails to evaluate the chronic toxicity of 4-NP. Its concentrations in collected water samples from Giza Governorate ranged from 400 to 1600&nbsp;μg/l. Based on these environmentally relevant concentrations, laboratory experiments were carried out using standard 4-NP to investigate the effect of three concentrations; namely 400, 750, and 1600&nbsp;μg/l. Survival rate of the exposed snails to 4-NP concentrations was affected after 4&nbsp;weeks. Reproduction of the exposed snails to 4-NP concentrations was lower than that of the control at 30&nbsp;°C, while the exposed snails to 400&nbsp;μg/l of 4-NP showed maximum reproduction at 15&nbsp;°C. The lowest hatchability percentage was recorded with egg masses laid by the exposed snails to 400 and 1600&nbsp;μg/l of 4-NP at 15 and 30&nbsp;°C, respectively. Furthermore, the results showed fluctuated levels of progesterone, estradiol, and testosterone depending upon the concentration and the temperature, which played a key role in determining the degree of 4-NP toxicity.</span></p>