RBP II (Rapid Bioassessment Protocol II) as a tool to assess the sediment and water quality in a treated textile effluent receiving stream ecosystem.

Macrobenthos are important bioindicators of organic and nutrient pollution. The present study used the macrobenthos based rapid bioassessment protocol (RBP II) to study the effects of treated textile effluent input into a natural stream ecosystem. Three reference sites and three sites with point source inputs from a textile effluent treatment plant were selected. The physical and chemical parameters and the abundance and diversity of macrobenthos at each site were assessed during the rainy and dry seasons of 2020. Although the water quality parameters at the point source inputs did not exceed the standard textile effluent discharge limits, a significant difference in the microbenthic community composition was observed at the effluent discharge receiving sites. The dominant macrobenthos in the ecosystem (Baetis sp., Leptophlebia sp and Tubifex sp.) showed significant correlations with Pb, Cu, Cr and Cd concentrations of the water and sediments. The Shannon-Weiner diversity index, family biotic index, EPT Index and EPT/C ratio which are used in rapid bioassessment protocol indicated significantly strong correlations with the water and sediment quality parameters and reflected their suitability to be used as a tool of biological measurements in the textile effluent receiving aquatic ecosystems.

Rapid Bioassessment Protocols Using Aquatic Macroinvertebrates in Africa–Considerations for Regional Adaptation of Existing Biotic Indices

Benthic macroinvertebrates are commonly used to assess water quality and ecological condition of aquatic ecosystems and they form the basis of several biotic indices. Many of these biotic indices are based on rapid bioassessment protocols (RBP). The first RBP based on macroinvertebrates, developed in Africa in the early 1990s, was the South Africa Scoring System (SASS). Since then SASS has been widely used in southern Africa and beyond, and has formed the basis of several other RBPs developed in Africa. This paper explores the RBPs and associated biotic indices currently used in Africa, primarily those that are rapid, field-based with low taxonomy (mostly family level) and which rely on sensitivity weightings of individual taxa to generate three metrics for interpreting water quality and ecological condition of aquatic ecosystems. Recommendations for future regional adaptation of RBPs, including calibration, validation, and modification of RBPs and biotic indices for new regions are provided. To date, five RBPs have been developed in Africa, while some existing biotic indices have been used outside their intended regional range. Key to the efficacy of any RBP and associated biotic index is the ability to detect a water quality impact, or change in river health. Important considerations when adapting an index for a new region or country include evaluating the suitability of the sampling protocol to local river conditions, evaluating the distribution of aquatic macroinvertebrate taxa in the region, assigning sensitivity weightings to new taxa in the region, evaluating the ability of the biotic index to detect impacts, evaluating within-country spatial and temporal variability in macroinvertebrate assemblages, and developing appropriate data interpretation guidelines based on metric scores and reference conditions. Often several iterations of a biotic index are needed, with improvement in efficacy with each version, following spatially and temporally comprehensive sampling. Future RBPs developed for bioassessment of rivers in Africa will promote the protection, conservation, and management of African riverine ecosystems.

Are different benthic communities in Arctic delta lakes distinguishable along a hydrological connectivity gradient using a rapid bioassessment approach?

Aquatic habitats in the Canadian Arctic are expected to come under increasing stress due to projected effects of climate change. There is a need for community-based biomonitoring programs to observe and understand the effects of these stressors on the environment. Here we present results from a 5 year annual sampling program of benthic invertebrates from lakes in the Mackenzie Delta, Northwest Territories, using a rapid bioassessment protocol. Connectivity between the deltaic lakes and main channels is a major driver of lake function and is expected to be substantially impacted by climate change. Lakes were selected along a gradient of connectivity based on sill elevation above the river. Using multivariate analyses of community structure, we determined that benthic assemblages responded to differences in connection time among lakes. This response was detected using a coarse taxonomic level that could be applied by community groups or volunteers but was stronger when invertebrates were identified to the family and genus levels. A secondary gradient was observed that corresponded to productivity gradients in lakes that are isolated from the river during summer. We show that benthic assemblages have potential use as sensitive indicators of climate-mediated changes to the hydrology of lakes in the Mackenzie Delta.