Determination of the Levels of Indicator Bacteria, Salmonella spp. and Heavy Metals in Sea Snails (Rapana venosa) from the Northern Marmara Sea, Turkey

Abstract

Sea snail (Rapana venosa) samples were collected from the northern coast of the Marmara Sea and analyzed to determine bacteriological pollution in the form of Faecal coliform, Esherichia coli, and Salmonella spp. as well as to measure levels of the heavy metals, Zn, Pb, Cu, Cd, As using by atomic absorption spectrophotometer. Samples were collected through the June 2000 - November 2001 from the shore and from depths of 10 – 12 meters of the northern Marmara Sea. Within the total of 75 groups of R. venosa samples which consisted of at least 6 individuals in each group, the highest bacteriological values, 11 x 10³ cfu/g Esherichia coli, >24 x 10³ Faecal coliform, were determined in the August sampling period. Salmonella spp. was determined in 2 groups of samples. Within the total of 55 groups of R. venosa samples, consisting of at least 3 individuals in each group, heavy metal levels ranged between Zn: 18.0–52.0 ppm, Pb: 0.52–1.25 ppm, Cu: 21.6–49.3 ppm, Cd: ND - 0.08 ppm. Arsenic was found below detection limit. No temporal variation was observed in the heavy metal concentrations.