Benthic invertebrate metals exposure, accumulation, and community‐level effects downstream from a hard‐rock mine site

Abstract

Abstract-This study quantitatively evaluated the relationships among As, Co, and Cu concentrations in exposure media (surface water, sediment, and aufwuchs), As, Co, and Cu concentrations in aquatic macroinvertebrates, and invertebrate community structure in a mine-affected stream. Concentrations of As, Co, and Cu were significantly elevated in both exposure media and invertebrate tissue downstream from the mine. Copper in invertebrates was significantly correlated only with Cu in aufwuchs, and Co in invertebrates was significantly correlated only with dissolved Co in water, suggesting different mechanisms of invertebrate accumulation for these two metals. The invertebrate community was severely affected downstream from the mine, with a loss of metalssensitive species and reductions in both total biomass and number of species. Total abundance was not affected. Principal components analysis was performed on the invertebrate community data to develop a simplified description of community response to mine inputs. Based on this index, metal concentrations in invertebrates were poor predictors of community structure. Copper concentrations in water, combined with an estimate of invertebrate drift from clean tributaries, were statistically significant predictors of community structure.

Macroinvertebrate Assemblages in Shale-Draining Streams of North-Central Arkansas, USA

“…Chadwick et al [40] also found low densities of Optioservus downstream from a mine input to a Rocky Mountain stream. Our findings are also contrary to those of Beltman et al [4] who observed that early instars of Optioservus spp. may be adversely affected by Cu concentrations as low as 5 g/L.…”

“…Similar observations on the two macroinvertebrate taxa were reported by Clements et al [33] and Beltman et al [4]. Studies by Plafkin et al [34] and Barbour et al [35] found Ephemeroptera, Plecoptera, and Trichoptera richness to be sensitive variables to a variety of stressors including metal contaminants.…”

“…Evidence from both field and laboratory studies indicate that metal contamination in streams may alter the composition and structure of macroinvertebrate communities [1][2][3][4][5][6]. Low total abundance and taxa richness of metal-sensitive macroinvertebrate taxa such as Plecoptera and Trichoptera have been noted in streams characterized by elevated metal levels [2].…”

“…heptageniid mayflies) is common in streams containing elevated metal concentrations [2,5,7]. Other studies have documented high abundance of metal-tolerant chironomids and oligochaetes in metal-contaminated waters and sediments [4,5,[8][9][10]. The observed low abundance of metal-sensitive macroinvertebrate taxa have been attributed to increased mortality, diminished growth, and low recruitment [2,5].…”

“…Box 419, State University, AR 72467, USA; Tel: 870-972-3086 Ext. 2399; Fax: 870-972-3089; E-mail: george1971ke@yahoo.com exposure to elevated metal levels and those that maintain steady populations through wind drift from sites that are unaffected by metals [4,12].…”