https://phys.org/news/2018-07-bioaccumulation-metals-aquatic-invertebrates-areas.html

A study conducted in mining areas in Asturias by the Animal Ecotoxicity and Biodiversity group led by Dr. Pilar Rodriguez, through collaboration between the Department of Zoology and Animal Cellular Biology and that of Genetics, Physical Anthropology and Animal Physiology of the UPV/EHU's Faculty of Science and Technology, and the Limnology Laboratory at the University of Vigo has enabled progress to be made in this field and has proposed the ecological threshold concentration for seven metals (cadmium, chromium, copper, mercury, nickel, lead and zinc) and two metalloids (arsenic and selenium). The study included a number of non-contaminated localities belonging to the reference network of the Nalón river basin as well as other highly contaminated ones. This is a basin with a long history of mining activities due to the high levels of metals naturally occurring in its rocks. "We selected this area because it is one of the areas in the Cantabrian region where the aquatic communities have a major problem of metal exposure," explained Dr. Pilar Rodríguez, member of the UPV/EHU's Department of Zoology and Animal Cellular Biology.

Specifically, the study proposes the ecological threshold concentration for the 9 chemical elements using the measurements in the tissue of 10 invertebrate taxa present in reference sites, in other words, in places with a minimum or zero impact by contaminants, and whose ecological status was evaluated as good or very good. It involves, as Dr. Rodríguez pointed out, "an innovative way of tackling the problem of Environmental Quality Standards; firstly, we selected the reference sites, and the 10 biomonitor taxa used to determine the metal bioaccumulation are the ones that tend to be found in both clean areas as well as in contaminated ones. "