Jacket Rivers, Zimbabwe: Use of the South African Scoring System and Habitat Assessment Index

Tazvivinga  .A.^1,*, Z. Jiri¹, S. Muyambo ¹, G. Nyamadzawo² and J. Gotosa²

¹Department of Biological Sciences, Bindura University of Science Education, P. Bag 1020, Bindura, Zimbabwe

²Department of Environmental Science, Bindura University of Science Education, P. Bag 1020, Bindura, Zimbabwe

Corresponding author Email: atazvivingarunesu@gmail.com

Accepted 19 October 2012

Abstract

This study assessed the water quality of Mazowe and Yellow Jacket Rivers which passes through Mazowe citrus estate and Iron Duke Pyrite mine (IDPM) respectively using physicochemical analysis and passive biomonitoring. The physicochemical parameters analysed were temperature, dissolved oxygen, pH, conductivity, phosphates, nitrates and heavy metals. Passive biomonitoring involved assessing benthic macroinvertebrate communities using the South African System Version 5 and habitat quality was assessed using the Habitat Assessment Index (HAI). The physicochemical parameters analysed were lowest at sites 2 and 3, when compared to the other sites. The concentration of nitrates, and phosphates was significantly higher at site 3-6 (p<0.05), when compared to the other sites. The concentrations of heavy metals were significantly higher (p<0.05) at sites 2-4 when compare to the other sites. Site 1 and 5 had higher SASS score and number of families, while the score per taxon (ASPT) was highest at site 1, 5 and 6. The results suggest that habitat quality in the Yellow Jacket River was poor compared to Mazowe Rives as a result of acidity and heavy metal contamination from IDPM. In Mazowe River high nitrates and phosphate concentrations from the estate, may affect the water quality.

Keywords: biomonitoring, river water quality, habitat assessment index, pollution, macroinvertebrates.