The Relationship between some heavy metal contents in the sediment and macrobenthic community in Gorgan Bay

Abstract

This study aimed to investigate the population of benthic communities in relation to heavy metal contents (Cu, Pb, Zn, Cr, Co) in sediments of Gorgan Bay. Thirteen sampling sites were selected and sampling was conducted using Van Veen sampler in summer of 1389. Regarding the obtained results, total organic compounds in the sediment ranged from %1.75 to %9 (averaged 4.45±1.72 (%)). The average amount of sand, silt and clay were 23.38±27.56 (%), 36.61±18.3 (%) and 39.76±14.40 (%), respectively. 5 classes, 8 families, and 8 species of macrobenthic communities were identified in Gorgan Bay. The population of macrobenthic communities ranged from 466.66 to 5100 (ind m-2) with the average amount of 2350.67±1450.78 (ind m-2). The indices of Eveeness, Shannon and Richness averaged 0.66±0.1, 0.78±0.45 and 0.69±0.35, respectively. Also, significant differences were observed amongst determined biological indices at various sampling sites (P<0.05). Concentrations of Cu, Pb, Zn, Cr, Co were 3.80-31.20, 4.10-18.30, 13-75, 3.50-20.80 and 13-52 mg kg-1, respectively. The average contents of heavy metal contents were (mg kg-1): Cu (17.86±9.19), Pb (11.33±5.16), Zn (42±23.23), Co (10.61±6.00), and Cr (31.69±15.71). Our results revealed that there was a negative correlation amongst all the determined biological indices and heavy metal contents in the sediment, demonstrating the negative impact of these metals on macrobenthic communities.