Taxonomy of benthic macroinvertebrates in Jajrud River for water quality assessment

Document Type: Research Paper

Authors

1 PhD candidate, Department of Environmental Pollutants Research, Environmental Sciences Research Institute, Shahid Beheshti University, Tehran, Iran

2 Associate professor, Department of Biodiversity and Ecosystem Management, Environmental Sciences Research Institute, Shahid Beheshti University, Tehran, Iran

Abstract

The invertebrates are one of the most important terrestrial fauna and freshwater taxa.
Benthic macroinvertebrates include aquatic insects and spiders, mites, crustaceans, and
species of mollusks and worms that are aquatic in their immature stages and terrestrial in
their adult stage. Jajrud River originates from the Alborz Mountains and is a source of
drinking water for people in eastern part of Tehran and the surrounding villages. For the
taxonomic identification of benthic macroinvertebrates, five stations downstream of Jajrud
were used. A Surber sampler device was used for sampling with dimensions 30 × 30 cm
and mesh size of 250 microns in all four seasons of the year 2013 with three repetitions at
each station. In total, five orders (Ephemeroptera, Coleoptera, Diptera, Trichoptera, and
Oligochaeta) and 13 families of benthic macroinvertebrates were identified. In all stations,
the family Baetidae (
Baetis sp .) belonging to the order Ephemeroptera had the highest
abundance, and seasonally the highest abundance was detected in autumn, winter, summer,
and spring respectively. After the identification of benthic macroinvertebrates, five biotic
indices including EPT, HFBI, SIGNAL, NJIS, and MMIF were calculated for water quality
assessment in downstream of the Jajrud River. Regarding the results of the biotic indices, it
can be said that the water quality of downstream of Jajrud River is not favorable. Therefore,
appropriate management measures should be taken to improve river water quality.