2.6 Water quality assessment based on the biotic index of
macroinvertebrates
\begin{equation}
\text{BI}\sum_{i1}^{S}{n_{i}a_{i}/N}\backslash n\nonumber \\
\end{equation}where ni represent the abundance of each species
in each sampling sites, ai represent the
tolerance values of each species and the N represent the total
abundance of each site. The key metrics of the B-IBI health assessment
system include: phylogenetic diversity (PD), the number of EPT
(Ephemeroptera, Plecoptera, Trichoptera) taxa, the percentage of
Ephemeroptera, the percentage of tolerant groups, BI (Biotic Index) and
the percentage of clingers. Based on BI values, sampling sites were
classified as follows: excellent (0-2.97), good (2.98-4.72), fair
(4.73-6.48) poor (6.49-8.24) and bad (>8.24), accordingly
to Satiou et al. (1987).
Results