Chemical assessment of water quality, heavy metals, and the distribution of zooplankton communities, based on field and GIS data in the drains of Burullus Lake, Egypt

Burullus Lake is the second largest of Egypt’s northern lakes, connected with the Mediterranean Sea through the El-Boughaz opening. The objective of this study aimed to evaluate water pollution in Burullus Lake drains and its relationship to zooplankton diversity, chlorophyll-a, in addition to Eutrophication status. Furthermore, a GIS model was applied to identify sites where high quantities of Zooplankton standing crops were recorded. The drains of Lake Burullus play important role in the distribution of zooplankton. Physico-chemical parameters, heavy metals (Fe, Zn, Pb, Cu, Ni, and Cr), and zooplankton were analyzed following APHA (2005). Nine water samples were collected seasonally from nine locations in the coastal zone of Burullus Lake for 2 years from Jan 2018 to November 2019. The results reveal that the pH levels are on the alkaline side, with a wide average (7.36), temperature (22.72), turbidity (23.72), salinity (4.30), high values of dissolved oxygen (8.44 mg L –1 ), and high concentration of nutrient salts, ammonia (0.82 mg L –1 ), nitrate (0.19 μg L –1 ), nitrite (74.5 μg L –1 ), total nitrogen (5.09 mg L –1 ), and total phosphate (228.96 μg L –1 ). Besides, the content of chlorophyll-a has fluctuated between 2.18 to 113.7 g L –1 . However, the maximum mean values of the tested heavy metals in water were exposed in the following order: Fe > Zn > Pb > Cu > Ni > Cr. On the other hand, zooplankton taxa in the drains of Burullus Lake recorded 49 species in this period. Rotifera, Copepoda, Protozoa, and Cladocera were the four groups that occurred in all periods, while the other species were rare. Furthermore, the highest temporally density was in 2019, while the lowest mean was recorded in 2018. The maximum spatially density was in Burullus west drain, while, the minimum was once Burullus Drain. The results of this study exhibited that the trophic state index (TSI) and the average water quality index (AWQI) confirmed that Burullus Drain water is a hypereutrophic state associated with poorly and moderately polluted of its water quality. It was concluded that Burullus Lake is extensively exposed to interrupting human activities which have a great negative impact on water quality.