SOME PHYSICAL FEATURES OF THE POLLUTED BASIN AND FISH FARM IN LAKE MARIUT, EGYPT.

SOME PHYSICAL FEATURES OF THE POLLUTED BASIN
AND FISH FARM IN LAKE MARIUT, EGYPT.
AMIN A. SAMAAN AND MAHMOUD A. ABDELMONEM
Institute of Oceanography and Fisheries, Alexandria, Egypt.
ABSTRACT
The physical cond1tionsin the polluted basin (Lake proper)
and fish fam in Lakl Mllrtut were estillllted monthly frOil
August 1975 to July 1977. The polluted basin receives IIlOst
of its water from the Qalaa Drain which Is contaminated
With sewage and industrial wastes. Other effluents ot s.wage
and industrial wastes were also discarded directly into
the basin through separate pipes.
Results indicate that these pollutants affect the physical
charateristics of the lake water. Thus, the water temperature
in the area surrounding the industrial wlSte disposal pipe
was relatively higher than the rest of the lake by values
rang1ng. from. O.S to i.aoe. Also, the temperature of the
bottom water in regions subjected to the d1rect outfall
of sewlge sustained higher temperature early in the morning
by about 0.5°C than. the surface water. due to putrefactioa
of organic detritus accUll1ll1ated on the bottom. The avaralJ;
Secchf depth nas been reduced to 20 cm in localities subjected
to dfrect pollution. The highest concentration of suspended
..tter was recorded around the sewage disposal pipe. reaching
about 84 IIQ dry ‘it/L.
The fisfi fal’ll WIS nearly free of pollution IS it recetves
IIOst of its Wlter from Hariut Et-Gedida Pumping Station.
The turbidity of water there was ..1nly due to the suspended
silt particles. The average Secch1 depth reached 68 em and
suspended ..tter amounted to about 62 IIQ dry ‘it/I..
The suspended ..tter in Qat .. Drain dropped to 24 mg
dry wt/l Ind the Secchi disc reading amounted to 44 ca.