As a component of a large research programme to evaluate the effects. of contaminants
on fish health in the fields , histopathological studies have been conducted to help establish
meat of causal relationships between contaminants exposure and various biological responses
and use of those responses as biomarker to aquatic pollution . Two fish species C. carpio
and L. abu were sampled from four sites near of industrialize and human pollution areas from _
Shatt Al-Arab River ,while the fifth place was considered as control because it's far located
from direct pollution sources . Some of histological and physiological alterations were
examined in both gills and blood . The alterations were significantly higher in fish collected
from two places ( 1 & 2 ) compare with other sites , histological was represented by
hyperplasia , hypertrophy , bleeding , inflammations , edema , necrosis , epithelial separation
and clubbing shaped , while , physiological was represented‘ by decrease of Na+ , K+ , Ca”
concentrations , Chloride cells number and increase of respiratory diffusion distance , in
addition to , increase of micronuclear of red blood cells . all fish in fifth place didn't showed
any histological and physiological responses and retained their rates of the normal level
compares with other places