Công nghệ xử lý rác MBT - CD.08 (Mechanic Bio Treatment)

BIOMARKERS AS INDICATOR FOR WATER POLLUTION

WITH HEAVY METALS IN RIVERS, SEAS AND OCEANS

M.NAGEEB RASHED

Faculty of Science, 81528 Aswan, South Valley University, Egypt

E-mail m nr as he d@h o t m a il. co m Fax 002 097 480 449

Water is one of our most important natural resources, and there are many conflicting

demands upon it. Skilful management of our water bodies is required if they are to be

used for such diverse purpose as domestic and industrial supply, crop irrigation,

transport, recreation , sport and commercial fisheries, power generation and waste

disposal. Water pollution is most commonly associated with the discharge of effluents

from sewers or sewage treatment plants, drains and factories to the water body of rivers,

seas and marines. In the attempt to define and measure the presence and effects of

pollutants epically the metals in rivers and oceans, the biological markers have attracted

a great deal of interest. The principle behind the biomarker approach is the analysis of

an organism metal content and compared the metal concentration with the background

metal levels. In this review, the data were collected from different literatures around the

world in using the aquatic organisms as biological indicator for metal pollution in

aquatic system.

INTRODUCATION

Water Pollution with metals

The aquatic environment with its water quality is considered the main factor controlling

the state of health and disease in both man and animal. Nowadays, the increasing use of

the waste chemical and agricultural drainage systems represents the most dangerous

chemical pollution. The most important heavy metals from the point of view of water

pollution are Zn, Cu, Pb, Cd, Hg, Ni and Cr. Some of these metals (e.g. Cu, Ni, Cr and

Zn) are essential trace metals to living organisms, but become toxic at higher

concentrations. Others, such as Pb and Cd have no known biological function but are

toxic elements.

Source of pollution with metals

Metals have many sources from which they can flow into the water body, these sources

are:

I Natural Sources: Metals are found throughout the earth, in rocks, soil and introduce

into the water body through natural processes, weathering and erosion.

II Industrial Sources: Industrial processes, particularly those concerned with the

mining and processing of metal ores, the finishing and plating of metals and the

manufacture of metal objects. Metallic compounds which are widely used in other

industries as pigments in paint and dye manufacture; in the manufacture of leather,