Comparing the responses of diatoms and macro‐ invertebrates to metals in upland streams of Wales and Cornwall

Abstract

SUMMARY 1. Surprisingly few data compare the apparent responses of diatoms and macroinvertebrates to metals in streams. We examined variation in metals, diatoms and macroinvertebrates between 51 streams in metal‐mining areas of Wales and Cornwall, U.K., using a survey design with multiple reference and polluted sites. 2. To quantify variations in metals between sites, we calculated cumulative criterion unit (CCU) scores, a recently defined measure of total stream metal concentration and toxicity, to account for additive effects of each metal relative to putative toxic thresholds. We compared assemblage responses among epilithic diatoms and macroinvertebrates to CCU scores or individual metal concentrations using correlation and detrended correspondence analysis (DCA). 3. Macroinvertebrate diversity, richness and total abundance declined and evenness increased with increasing copper concentrations. Trends with CCU scores were significant but less pronounced. Some individual macroinvertebrate taxa varied significantly in abundance with CCU scores, copper or zinc, but overall assemblage composition correlated only with manganese, pH and nitrate. 4. Among diatoms, pH and conductivity explained the major variations in assemblage composition, and neither diversity, richness nor evenness varied with metal concentration. Nevertheless, the single strongest predictor of diatom assemblages on ordination axis 2 was the CCU score. The abundances of some macroinvertebrate taxa, particularly grazers, also explained significant variations in diatom assemblages that were linked to both metals and acid–base status. 5. Diatom species apparently tolerant of high metal concentrations included Psammothidium helveticum, Eunotia subarcuatoides, Pinnularia subcapitata and Sellaphora seminulum. Of these, P. helveticum, E. subarcuatoides and P. subcapitata were abundant at lower pH than S.seminulum and might indicate metal enrichment over different pH ranges. Sensitive species included Fragilaria capucina var. rumpens, Achnanthes oblongella and Tabellaria flocculosa. 6. We conclude that macroinvertebrates at these sites reflected metal pollution most strongly through variations in diversity while effects on diatoms were best reflected by changes in assemblage composition. We suggest that, with further refinement, CCU scores might be useful in evaluating the possible effects of metal pollution on benthic organisms in European rivers.

An integrative assessment of environmental degradation of Caveira abandoned mine area (Southern Portugal)

“…As the criterion values are only available for individual elements, alternative models are necessary to estimate toxic effects of metal mixtures, hence the derivation of the CCU was used (Clements et al, 2000). The EPA metal thresholds considered are based on toxicity tests of species from different trophic levels, including macroinvertebrates (Hirst et al, 2002). The enrichment factors (CCU) calculated with respect to the EPA guidelines showed that the concentrations of Al, As, Cd, Cu, Fe, Mn, Ni, Pb and Zn were enriched and exceeded their maximum permissible levels (Table 4).…”

“…This criterion has been already applied to analyse the response of different organisms to metals in streams (Clements et al, 2000;Hickey and Golding, 2002;Hirst et al, 2002). The authors have followed the USEPA chronic criterion values for Al (87 μg L −1 ), Fe and Mn (1000 μg L −1 ), whilst the criterion values for Ag (1.…”

Bioaccumulation of metals in aquatic insects of streams located in areas with sugar cane cultivation

“…7 It is well known that high metal concentrations in aquatic ecosystems lead to a reduction of macroinvertebrate richness and abundance. 15,20,[36][37][38][39] In Brazilian streams, Chironomus and Odonata larvae can survive even in sites with very low environmental quality because they are tolerant to many disturbances. 20,40,41 Our results also show that it is possible to analyze metal concentrations in these aquatic macroinvertebrates even when the community is very poor, as occurs in sites near to the sugar cane culture…”

Invisible Face of Boron Pollution in Fluvial Ecosystem: The Level in the Tissues of Sentinel and Nectonic Organisms

“…Zoobenthic forms, such as Crustaceae, insect larvae, and annelida, are often the main diet for many fish species (especially Cyprinids) and may contribute to the transfer of metals to higher trophic levels. Although, boron was found to be neither genotoxic nor carcinogenic for human health (WHO 1998b), and no negative effects of boron on reproductive health were found (Ş aylı et al 1998), it is well known that high metal concentrations in aquatic ecosystems lead to a reduction of macroinvertebrate richness and abundance (Watanabe et al 2000;Hirst et al 2002;Smolders et al 2003). This makes it possible to analyse metal concentration in this invertebrate even when the community is very poor as at some sites along the Emet and Orhaneli rivers.…”