This study aimed to investigate the population
of annelida communities in relation to environmental factors
and heavy metals accumulated in sediments of the
Gorgan Bay. The pollution load index and potential ecological
risk (PER) were calculated. The results indicated
mean concentrations (ppm) of heavy metals were
(mean ± SD) Pb: 11.5 ± 4.88, Cu: 18 ± 8.83, Zn:
42 ± 22.15, Ni: 29.20 ± 14.68, Co: 10.56 ± 14.68, As:
7.77 ± 2.12, Sr: 1,449 ± 902.59 and V: 26.64 ± 10.25.
Considering PER, sediments of the Gorgan Bay had low
ecological risk. Based on abundance data, dominant species
were
Streblospio gynobranchiata
,
Nereis diversicolor
,
Tubificoides fraseri
and
Tubificidae
unknown, respectively.
Results of redundancy analysis displayed that
T. fraseri and
N. diversicolor were associated with high values of Sr. All
the species were negatively correlated with As. There were
positive correlation between
S. gynobranchiata and
N. diversicolor
with values of clay, salinity, depth and silt. The
present study provided the relative importance of heavy
metals and environmental variables which partly assist in
structuring assemblages of annelida in a transitional area.
