Date of Award

1-1995

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Science

First Advisor

Dr.Saif Al-Ghais

Second Advisor

Ibrahim Wasif

Third Advisor

Mohammed Tharek Mohammed Zaki

Abstract

Investigation of heavy metals in fish is an important aspect of environmental pollution as human activities contribute to the progressive increase in the concentration of metals in the environment as well as aquatic system. Therefore, an analytical survey for the contents of copper, zinc, manganese, and cadmium in liver, heart, kidney, muscle and skin of Lethrinus lentjan, collected from the western coast of the United Arab Emirates (Ras AI-Khaima) was carried out. The range and mean values of the levels of metals were determined and compared with the reported values in the Arabian Gulf.

Significant concentrations of the elements tested were detected by Atomic Absorption Spectrophotometric technique. Their values of metal levels were within the permissible limit for human consumption. The correlation coefficients between the metal concentrations in different tissues and various length groups were also determined.

The accumulation pattern of the essential elements Zn, Cu and Mn, and non-essential element Cd in the liver follows the sequence:

Zn > Cu > Mn > Cd

while in skin tissue the sequence of the metals follows the order:

Zn > Cu > Mn > Cd

In muscle the sequence of the accumulation behavior follows the order:

Zn > Cu > Cd ≅ Mn

The distribution behavior of the elements in fish kidney was found to follow the sequence:

Zn > Cu > Mn > Cd

However, in fish heart the sequencem as follows:

Zn > Cu > Cd > Mn

The mean concentrations (mean ± 5.0) of Cu, Zn, Mn, and Cd in fish liver was found to be 48.8 ± 1.71, 55.3 ± 32.98, 1.22 ± 0.23, and 0.66 ± 0.28 ppm, respectively. However, in skin the concentration was much lower and were as follows: 0.33 ± 0.13, 38.59 ± 8.35, 0.16 ± 0.11, and 0.08 ± 0.06 ppm, respectively.

Also in muscle the metals concentrations were found to be much lower than those in liver; the levels obtained were as follows: 0.17 ± 0.06, 3.31 ± 0.39, 0.11 ± 0.02, and 0.11 ± 0.02 ppm, respectively.

The study shows a negative correlation between the concentrations of Mn and Cd in fish muscle and fish length (age). Also in skin tissues the concentration of Mn shows a negative correlation with fish length (age), while a positive correlation was observed with copper. Moreover, a positive correlation was noticed between Cu, Zn and Cd concentrations in liver and fish length (age).

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