Bioaccumulation of total petroleum hydrocarbons and measuring the concentrations of some heavy metals in the water and two species of Gastropoda Melanopsis costata and Melanopsis nodosa in Al-Diwaniyah River, central Iraq

The current study aimed to detect  the level of pollution of the Diwaniyah River water and two species of gastropods ( Melanopsis costata  and Melanopsis nodosa with total petroleum hydrocarbons (TPHs) and some heavy elements. Three stations were chosen to collect water samples and snails. The first station is located at the entrance to the city, the second in the city center far 12 km2 and the third at the exit  far 10km2. chemical tests were conducted on the samples and snails to detect the level of pollution. The total levels of hydrocarbons in the water of the Diwaniyah River, were 2.4, 3.3 and 4.0 μg/g in the month of September for the three stations under study (S1,S2 and S3) respectively, while it was 2.5,3.1 and 4.3 μg/g for the month of October, respectively, for the three stations under study. The THPs in snails in the first station were the lowest 0.23 μg/g for M. costata and 0.31 μg/g for M. nodosa, followed by the second station, which was the most polluted, then the third station was the most polluted, with a rate for the snails 0.84 μg/g and 0.81 μg/g for above snails respectively. Regarding heavy metals in water , high levels of ( Fe) were recorded in station three, reaching 4.1 and 4. 66 ppm for the months of September and October, respectively, while (Cu) concentrations were recorded at 0.05 and 0.04 ppm for the above two months, respectively.      Heavy metals in snails were as follow: Station No. 3 was the highest contamination compared to other stations, where the concentration of heavy elements was high for (Cr) , it was the highest concentration, where M. costata was  0.05 and 0.04 mg/g for September and November, respectively, and for  M. nodosa  0.75 and 0.79 mg/g respectively, while (Fe) concentrations were 0.71, 0.69, 0.66 and 0.70  mg/g for the same station, species and months, respectively.