We request that you include a packing slip or chain of custody form with each shipment. This allows for us to confirm that we have received the correct samples for each site. All samples should be clearly labeled, preferable with 2 labels per container (outside label and an additional label within the sample). This insures that there will not be any error in the event the preservative leaks and causes the exterior label to rub off. We suggest shipping samples in a cooler so that samples to be contained in the even that one does open or break during transit.
Hilsenhoff FBI uses assigned tolerance values for each family as an initial assessment for detecting sites of intermediate impairment, and can be used to prioritize sites for more intensive evaluation. Tolerance values range from 0 to 10 for families and increase as water quality decreases. The index was developed to summarize the various tolerances of the benthic arthropod community with a single value.
Simpson's Diversity Index is a measure of diversity, which takes into account the number of species present, as well as the relative abundance of each species. As species richness and evenness increase, so diversity increases.
Shannon-Wiener Diversity Index is another index that is commonly used to characterize species diversity in a community. This measurement accounts for both species richness and proportion of each species present.
Pielou's evenness is a measure of biodiversity that quantifies how equal the community is numerically.
% Chironomidae is the percentage of individuals in the sample that are from the Family Chrionomidae. This number will indicate whether the stream is oligotrophic or eutrophic, and often this value will increase with decreasing water quality, as Chronomidae are tolerant of heavy metals and other pollutants.
% EPT is a value that looks at the percentage of individuals that are from the Orders of Ephemeroptera, Plecoptera and Trichoptera. These Orders are very sensitive to pollutants, and therefore will decrease as water quality decreases.