Influence of Aldrich humic acid and metal precipitates on survivorship of mayflies (Atalophlebiaspp.) to acid mine drainage

Abstract

Humic substances (HS) have been shown to decrease the toxicity of environmental stressors, but knowledge of their ability to influence the toxicity of multiple stressors such as metal mixtures and low pH associated with acid mine drainage (AMD) is still limited. The present study investigated the ability of HS to decrease toxicity of AMD to mayflies (Atalophlebia spp.). The AMD was collected from the Mount Morgan (Mount Morgan, Queensland, Australia) open pit. Mayflies were exposed to concentrations of AMD at 0%, 1%, 2%, 3%, and 4% in the presence of 0 mg/L, 10 mg/L, and 20 mg/L Aldrich humic acid (AHA). A U-shaped response was noted in all AHA treatments, with higher rates of mortality recorded in the 2% and 3% dilutions compared with 4%. This result was linked with increased precipitates in the lower concentrations. A follow-up trial showed significantly higher concentrations of precipitates in the 2% and 3% AMD dilutions in the 0 mg/L AHA treatment and higher precipitates in the 2% AMD, 10 mg/L and 20 mg/L AHA, treatments. Humic substances were shown to significantly increase survival of mayflies exposed to AMD by up to 50% in the 20 mg/L AHA treatment. Humic substances may have led to increased survival after AMD exposure through its ability to influence animal physiology and complex heavy metals. These results are valuable in understanding the ability of HS to influence the toxicity of multiple stressors.

Mining‐caused changes to habitat structure affect amphibian and reptile population ecology more than metal pollution

“…Because of generally slow accumulation rates, woody debris may need to be supplemented to speed up the process. Furthermore, adding woody debris may also be a better alternative to commonly employed liming (to raise pH and reduce the availability of metals), because the addition of lime can increase the toxicity of metals for some organisms (Holland et al 2014). In fact, liming may be unnecessary in our study sites, given that water pH is well above the values known to affect amphibians (Pierce 1985, Glooschenko et al 1992, Karns 1992 and their food taxa (e.g., periphyton; Lacoul et al 2011) and soil pH, albeit low, is comparable to that in reference sites.…”

Humic acid decreases acute toxicity and ventilation frequency in eastern rainbowfish (Melanotaenia splendida splendida) exposed to acid mine drainage

“…This is the first study to show that HA significantly decreases ventilation frequency and acute toxicity in fish exposed to AMD. HA have been shown previously to increase survival of shrimp and mayflies to AMD (Holland et al, 2013(Holland et al, , 2014b. This study and results provided in Holland et al (2013Holland et al ( , 2014a, suggest that the presence of HA has a positive effect on aquatic organisms and may aid their survival to multiple stressors such as low pH and heavy metal mixtures associated with AMD.…”

“…D), and mayflies (Atalophlebia spp.) after 96 h (Chapman and Simpson, 2005;Holland et al, 2013Holland et al, , 2014b.…”

Catchment liming creates recolonization opportunity for sensitive invertebrates in a smelter impacted landscape

“…4). Such precipitates are known to impact invertebrate and microbial communities (Siefert and Mutz, 2001;Holland et al, 2014).…”