الفهرس 
methodologyOnly 14 pages are availabe for public view
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Abstract
SUMMARY
Lake Qaroun, which is one of the largest lakes in Egypt, is
a remnant of a much bigger one; historic lake ”Moreis”, and was
originally a freshwater lake, considered as a closed basin used as a
general reservoir for agricultural waste water drainage of ELFayoum
province. Moreover, the lake receives the agricultural and
sewage drainage water from El-Fayoum governorate, as well as,
the drainage of the fish farms.
The present field investigations include the study of water
quality of samples collected directly from different sites along
Lake Qaroun, The first site (Site I) is the eastern sector of the lake
where effluents of El-Bats drain discharged directly, Southeastern
sector of the lake where the effluent of an agricultural canal called
El-Wadi drain (Site II) and the western sector of the lake where no
effluents were recognized (Site III). Moreover, the study also
includes the effect of effluents discharged directly to the studied
sites of the lake on the growth indices and the quality of Mugil
cephalus and Solea solea collected from the same localities under
investigation. It was also concerned with the study of some
physiological and biochemical parameters of fish reared in the
different studied sites.
Water quality:
It is evident that, the highest value of dissolved oxygen
was recorded western sector of the lake (site III) followed by
southeastern sector (site II) and eastern sector (site I). This may be
due to that, the agricultural discharge high levels of organic
substances, inorganic salts and heavy metals that leading to
hypoxia and causing fish mortality (El-Naggar, et al., 1998;
Haggag, et al., 1999 and Salah El-Deen, et al., 1999). The present
data also showed high values of water ammonia and nitrite in
water samples collected from the eastern and southeastern sectors
of the lake and the lowest values were recorded at western sector.
Comparing the average concentrations of heavy metals (Cu++,
b++, Zn++ and Cd++) in water from the different studied locations,
the results revealed the presence of metals as follows:
Copper (Cu++) : Eastern sector of the lake > Southeastern sector
of the lake > Western sector of the lake.
Zinc (Zn++): western sector > Southeastern sector of the lake >
Eastern sector of the lake
Cadmium (Cd++): Eastern sector of the lake > Southeastern
sector of the lake > western sector.
Lead (Pb++): Eastern sector of the lake > Southeastern sector of
the lake > Western sector of the lake
The results declared that in presence of the industrial and
agricultural effluents discharged directly to the eastern site of the
lake (Site I) and the agricultural effluents discharged directly to
the southeastern sector of the lake(site II), the concentrations of
copper, lead, zinc and cadmium in water were higher than that of
samples collected from western sector (Site III). However, lead
concentrations recorded in water collected from the eastern site is
higher than southeastern sector.
Water heavy metals:
Metals examined in this study were copper, zinc, cadmium
and lead. There were highly significant differences in
concentrations of these metals in water samples collected from the
different studied sites. The highest values for copper, Zinc,
cadmium and lead were recorded in samples of eastern sector of the
lake followed by that in water samples collected from southeastern
sector of the lake. and finally the western sector of the lake have the
lowest values.
Sediment heavy metals:
Comparing the average concentrations of heavy metals
(Cu2+, Zn2+, Cd2+ and Pb2+) in sediment samples collected from
the different sites along Lake Qaroun, the results revealed the
presence o these metals in the following order:
Copper: eastern sector > western sector > southeastern sector.
Zinc: western sector > southeastern > eastern sector.
Cadmium: eastern sector > southeastern sector > western sector.
Lead: eastern sector > southeastern sector > western sector.
Residual heavy metal concentrations:
It is clear from the present results that the highest
concentrations of the different heavy metals were found in fish
collected from the eastern and southeastern sectors of the lake in
the following order: liver tissues> kidneys> gills> muscles in case
of copper bioaccumulation; Gills > liver> kidney and muscles in
case of lead bioaccumulation. However, zinc bioaccumulated in
fish kidneys at higher concentrations than those in liver. The
results also declared that the lowest concentrations of the studied
heavy metals were recorded in tissues of fish collected from the
western sector that lies away from any source of pollution.
Generally, the concentrations of the studied heavy metals in tissues
of both fish species were in the following order:
Copper: Liver > Kidneys > Gills > end of alimentary canal >
Muscles.
Zinc: Kidneys > Liver > Gills > Muscles. > end of
alimentary canal.
Cadmium End of alimentary canal > Kidneys > Gills > Liver
>Muscles in case of Solea solea.
Gills > Kidneys > end of alimentary canal > Liver
>Muscles in case of Mugil cephalus.
Lead: Kidneys > end of alimentary canal > Liver > Gills
>Muscles.
Histological studies:
Bioaccumulation of heavy metals in fish tissues led to
histopathological alterations in gills, liver and kidneys of both
studied fish species collected from the eastern and southeastern
sectors of the lake. Sections of gills, liver and kidneys of Mugil
cephalus and Solea solea collected from the western sector were
more or less similar and resemble that of normal fish. However,
histopathological alterations and clear damage were obvious in
gills, liver and kidneys of both fish species collected from eastern
and southeastern of the lake. These alterations were generally in
accordance with the results of residual heavy metals in tissues and
the most damaged tissues were in both fish species collected from
the eastern sector of the lake.
Growth indices:
Lake Qaroun fluctuated to be the highest in fish collected
from western sector of the lake and the lowest in fish collected
from the eastern and western sectors of the lake.
Blood parameters:
Data representing blood parameters of Mugil cephalus and
Solea solea collected from the different studied sites along Lake
Qaroun are given in the present study. They include the red blood
cell counts (RBCs), haemoglobin content (Hb), haematocrit value
(Ht), mean corpuscular volume (MCV), mean corpuscular
haemoglobin (MCH), mean corpuscular haemoglobin
concentration (MCHC) and white blood cell counts (WBCs). The
highly significant decrease in RBCs, Hb and Ht values of fish
collected from the eastern and southeastern sectors of the lake in
relation to those of the fish collected from western sector that
revealed more or less normal values.
Comparison of the white blood cell counts of Mugil
cephalus and Solea solea declared that, there was highly
significant difference in WBCs of fish collected from the different
studied sites along Lake Qaroun. Moreover, fish collected from
the eastern and southeastern sites of the lake showed a significant
increase in WBCs count, compared to that of fish collected from
western sector of the lake. The results also revealed significant
differences in the mean corpuscular volume (MCV) mean
corpuscular haemoglobin (MCH) and mean corpuscular
haemoglobin concentration (MCHC) of Mugil cephalus and Solea
solea collected from the different studied sites along Lake Qaroun.
Serum constituents:
The results declared highly significant differences in
serum glucose, total protein, creatinine, uric acid, AST and ALT
activities for the studied fish species Mugil cephalus and Solea
solea collected from the different studied sites along Lake Qaroun.
Generally, the higher values for all these parameters were
recorded in samples of both studied fish species collected from
eastern and southeastern sectors of the lake that exposed to the
agricultural drainage water of El-Fayoum Governorate. However,
the normal values were recorded in fish samples of the western
sector of the lake.
Meat quality (muscle chemical composition):
Data representing the changes in meat quality (muscle
chemical composition) of Mugil cephalus and Solea solea
collected from the different studied sites along Lake Qaroun
indicating that they were significantly different. In the present
field study, fish exposed to agricultural effluents in the lake at
eastern and southeastern sectors showed deterioration in meat
quality, where there were significant increases in muscle water
content and ash with significant decreases in the muscle total
protein and total lipids.
Generally, it could be concluded that fish collected from
the western sector of the lake revealed high growth indices, high
meat quality as well as safe flesh for Human consumption.
However, effluents of the drainage water discharged directly,
without prior treatment, to the eastern and southeaster sectors of
lake Qaroun suppress fish growth and deteriorate its meat quality
and hence become a threat to man