International Journal of Marine Science 2016, Vol.6, No.26, 1-13
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3 Materials and Methods
3.1. Sampling stations
Seven stations have been selected in the western side of the northern part of the Gulf of Suez for sampling with
regards to the sources of pollution in the present study area.
Station (1): Summer Palace Hotel beach (west of Port Tawfic Harbour): It is affected by tourist and fishing
activities. It is a semi-closed area with a low wave motion and broad tide.
Station (2): El-Zeitiya Harbour: It is affected by refineries and shipping activities of petroleum tankers.
Station (3): El-Kabanon beach: This station is affected by the domestic effluents from the old sewage plant of the
Suez City and effluent of thermo-power station. Its beach is characterized by a muddy substrate.
Station (4): Ataka Electric Power Plant: It receives the waste water from the power station as well as drainage
water from the Fertilizers Company.
Station (5): Beach of the National Institute of Oceanography and Fisheries (NIOF): It receives water from the new
sewage treatment plant of the Suez City, as well as the wastes of the Vegetable and Oil Company, Steel factory
and the Trust textile factory.
Station (6): North of the Adabiya Harbour: It is affected by the shipping and trading operations in the harbour as
well as the untreated sewage from a small nearby community.
Station (7): Sand Beach Resort shore: It is affected by tourist activities especially during summer season.
3.2 Sampling
Surface sandy/clay sediments and marine bivalves were collected twice during summer 2014 and winter 2015
from the intertidal area of the studying stations (Fig. 1). This area hosts a large part of the industrial and residential
activities.
Surface sediment samples were collected from the intertidal area using plastic spatula. The samples were stored in
plastic bags and transferred to the laboratory, air dried at room temperature and stored in plastic bags until
analysis.
In the present work, one species was selected as potential quantitative bioindicators “
Brachidontes variabilis
”.
This species, also known as
Mytilus arabicus
, is a typical inhabitant of hard substrata and lives in shallow water
(at sea level or just below) attached mostly in clusters to rocks and stones by its byssus. Its abundance seems to be
negatively associated with wave exposure.
Bivalve species (
Brachidontes variabilis
) was collected from the different study stations. Organisms were
collected in polyethylene bags and transferred to the laboratory in ice box, where they were identified and cleaned,
then frozen at -20 ºC until analysis.
3.3 Analysis
Dried Surface sediment samples were sieved and 0.5 g of the fine fraction (< 0.063 mm) was digested according
to Oregioni and Aston (1984) technique; concentrated nitric, perchloric and hydrofluoric acids were added in the
ratio of 3:2:1 to the sample in Teflon vessels and left overnight. The sample was then heated to 100 ºC for about
two hours, cooled, filtered and diluted to 25 ml with deionized water. Metals were determined by Flame Atomic
Absorption Spectrophotometer (FAAS Perkin Elmer model AAnalyst 100); the results obtained were expressed in
µg/g.
Brachidontes variabilis
were thawed and rinsed in distilled water. The preparation of samples to determine
concentration of heavy metals was carried out according to FAO (1976). Total soft tissues were separated from the
shells, weight and digested at 100 ºC using AR conc. nitric acid in Teflon digested vessels. Replicate samples from
