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International Journal of Marine Science 2014, Vol.4, No.35
http://ijms.biopublisher.ca
7
Figure 6 The concentrations of the parameters under investi-
gation at the breaker zone
1.1 Surf Zone
Due to erosion status of Rosetta and Damietta
promontories, the depths in front of Rosetta (east and
west) and east of Ras El-Bar sea walls are more than
0-2 m and there is no surf zone at their coasts as
shown in Figure 4. The other three stations (W_B,
E_B and W_R) are representing accretion status with
different rates at surf zone. As shown in Figure 1, the
higher accretion rate has been observed at Eastern
El-Burullus surf zone than west of El-Burullus during
the period from 2004 to 2008. As shown in Figure 5,
the eastern side of El-Burullus characterized by
relatively lower amount of fine sand and appearance
of coarse sand, medium sand and very fine sand. Also,
relatively small amount of
226
Ra,
232
Th and
40
K have
been detected at surf zone of east of El-Burullus. The
western side of Ras El-Bar surf zone has characterized
by relatively high amount of fine sand, low amount of
medium sand, relatively higher amount coarse sand
and very coarse sand as shown in Figure 5. Relatively
high amount of
226
Ra,
232
Th and
40
K have been
detected at surf zone of west of Ras El-Bar. Therefore,
the accreted sands contain much more coarser grains
than the eroded ones. In the natural separation the
heavy minerals increase in the beach surf face due to
the action of waves. On the other hand, the lighter
minerals increase seaward due to their settling in a gradual
decrease of energy levels (El-Askary and Badr, 1996).
1.2 Breaker Zone
In general, it may be said that the coarse material
tends to accumulate in the breaker zone and starts
getting progressively finer seaward as the wave
energy reduces in that direction. The breaker zone
sediments revealed a higher content of less heavies
and lower content of more heavies than in the beach
surf face sediments (Badr et al., 1993). Due to
severe erosion history of Rosetta, the depths in front
of Rosetta (east and west) sea wall are also more than
2-4 m and there is no breaker zone at their coasts as
shown in Figure 1. At breaker zone, east of
El-Burullus is still the higher accretion rate
characterized than its western side by relatively lower
fine sand and relatively higher amounts of the heavy
elements and the natural radionuclides under
investigation is detected in relatively higher amount at
2-4 m depths as shown in Figure 6. At west of Ras
El-Bar the amount of fine sand is decreased than at
surf zone and the coarse sand and very coarse sand
have been observed at this zone. On the other hand,
erosion site at this zone is the eastern part of Ras
El-Bar, which characterized by low amount of
medium, coarse sand and silt and relatively higher
amount of
226
Ra and
232
Th but low
40
K.
1.3 Offshore Zone
As shown in Figure 1, west Rosetta and east El-
Burullus profiles are indicated erosion and accretion
along their profiles, respectively. The other profiles
under investigation were characterized by reverse
processes from erosion to accretion such as east
Rosetta and east Ras El-Bar, and from accretion to
erosion such as west of El-Burullus and west of Ras
El-Bar. Close relations of heavy elements distribution
have been observed at Figure 7 between east Rosetta
and east Ras El-Bar and with west El-Burullus and
west of Ras El-Bar. On the other hand, no coarse sand
or very coarse sand have been detected at the erosion
sites as west of El-Burullus and West of Ras El-Bar
have relatively higher amount of
226
Ra and
232
Th.
2 Conclusion
It is concluded that the radioactive materials detected
in the Nile Delta coastal profiles are naturally
occurring and its distribution is dependent mainly on
the coastal processes. The conclusion can be
summarized as the following points: