Assessment of environmental toxicity in Iraqi Southern marshes using fish as bioindicators

Abstract

A moderate level of pollution with petroleum hydrocarbons and traces of heavy metals has been detected in some sites of the Al-Hammar marshes. Lower levels were also found in the Al-Huwaiza marsh. Fish (Himri, Barbus luteus) in the possibly polluted area gave signs for unhealthy environment by accumulating higher levels of pollutants in their muscles and gonads as compared with those monitored in the more healthy area. Disturbance in the age structure of the fish population was also recorded, with the dominance of certain length groups and ages in the polluted areas. A delay in gonad maturation and disturbance of sex ratio were noticed in the stations with higher levels of pollutants. A remarkable increase in metabolic enzymes which suppose to work in liver was noted in the fish inhabiting the polluted area. The biochemical constitutes of blood serum were found to be altered in the polluted areas with a decrease in total protein, albumin and cholesterol concentrations indicating a possible case of loosing blood to the tissues or inefficiency in liver function. It is concluded that fish conditions in some parts of the Al-Hammar marsh indicate the unhealthy environment which is obvious by some physiological responses due to the presence of pollutants. There is an urgent need to set up a long-term programme of research and a monitoring system to assess the pollution status in the newly flooded marshes. Further histological and bio-markers studies are strongly recommended. Keywords: hydrocarbons, heavy metals, toxicity, fish, Iraqi marshes