Rapid recovery of benthic invertebrates downstream of hyperalkaline steel slag discharges

Abstract

This study assesses the physical and chemical characteristics of hyperalkaline steel slag leachate from a former steelworks on two streams in England and their impacts on 24 benthic invertebrate communities. Using multivariate methods (CCA), we related 25 invertebrate richness and diversity with chemical parameters along the environmental 26 gradient from point sources to less impacted sites downstream. Point discharges are characterised by high pH (10.6-11.5), high ionic strength (dominated by Ca-CO3-OH 28 waters), elevated trace elements (notably Li, Sr and V) and high rates of calcium 29 carbonate precipitation. This combination of stressors gives rise to an impoverished 30 benthic invertebrate community in source areas. The total abundance, taxonomic 31 richness and densities of most observed organisms were strongly negatively correlated 32 with water pH. Analysis using biological pollution monitoring indices (e.g. BMWP and Functional Feeding Groups) shows the system to be highly impacted at source but when pH approaches values close to aquatic life standards, some 500m downstream, complex biological communities become established. In addition to showing the rapid recovery of invertebrate communities downstream of the discharges, this study also provides a baseline characterisation of invertebrate communities at the extreme alkaline range of the pH spectrum.

What Causes Carbonates to Form “Shrubby” Morphologies? An Anthropocene Limestone Case Study

“…Hydrochemistry at each of the sampling sites on the day of sampling is summarized in Table 1, and is consistent with previous (Mayes et al, 2008) and more recent (Hull et al, 2014;Riley and Mayes, 2015;Hobson et al, 2018;Mayes et al, 2018) monitoring of these systems. Some calcium is sourced from background seepage of karst groundwater into both streams, but the majority is derived from steel slag leachate in the form of Ca(OH) 2 .…”

“…Total alkalinity shows the same enhancement at proximal sites (55-59 mg.L −1 in Dene Burn and 264-332 mg.L −1 in Howden Burn). Given this water composition, it is unsurprising that calcite saturation index is very high (+0.04 to +2.47), and mineral precipitation is high enough to be lethal to local microbenthos by smothering (Hull et al, 2014).…”

Main and Trace Element Distribution in Slag-Leachate-Tufa System Precipitate

“…Several studies have confirmed the negative influence of limed waters on aquatic life [18][19]. The leachate and groundwater pH is above the regulatory threshold for discharge to water bodies.…”

Determination of lithium bioretention by maize under hydroponic conditions

“…battery disposal, use of biosloids, aluminum processing, glass and ceramic production (Enghag 2008, Al-Thyabat et al 2013, Hull et al 2014 raises the question to what extent this will lead to environmental pollution. High lithium concentration in solutions can be toxic to plants (Bradford 1963).…”