Snails and Fish as Pollution Biomarkers in Lake Manzala and Laboratory A: Lake Manzala Snails

Abstract

Physiological, hematological and biochemical parameters have been used as biomarkers for water quality in snail samples collected from Lake Manzala. The results showed significant increase in AST, ALT, and ALP in planorbis and Physa snail samples collected from Dakahlya site in Lake Manzala. Most of snails are collected from of Port-Said and Dakahlya sites showed significant increase in urea. On the other hand, alteration in creatinine values in samples from different lake sites was recorded. Significant increase of total protein level and total bilirubin was obtained in all samples. Most of snail samples showed significant decrease in hemocytes count. The oxidative enzymes (CAT, GGT and GST) recorded alteration in their activity. Regarding Histopathological observations, in the foot region of Biomphalaria snails collected from Port Said and Dakahlya governorates are the most affected. The head foot showed splitting in the longitudinal and oblique muscle fibers and increased empty spaces within muscle. Shrinkage, focal areas of necrosis, large fat vacuoles and enlargement were observed in the salivary gland. Snail’s ganglia showed enlargement of neurosecretory neurons, degeneration with large vacuoles and fibrosis. hepatopancreas became much more distorted with necrosis, atrophy, degeneration and fat vaculation especially in Port Said and Damietta samples. Also, hepatopancreatic acini filled with different developmental stages of S. mansonai cercariae were observed in Biomphalaria snails collected from Port Said. Severe degenerative changes were observed in most of gonad’s cells including ova and sperms especially in snails collected from Damietta. Also, Biomphalaria snails collected from Lake Mazala showed accumulation of heavy metals in the head foot tissues. In conclusion, the severe alteration and degeneration recorded in the physiological and hematological parameters and also histopathological observations are clear evidence for the pollution of the water from which these snails were collected.