Effects of mine tailing exposure on early life stages of cod (Gadus morhua) and haddock (Melanogrammus aeglefinus)

Julia Farkas,Trond Nordtug,Linn H Svendheim,Elettra D Amico,Emlyn J Davies,Tomasz Ciesielski,Bjørn Munro Jenssen,Torstein Kristensen,Pål A Olsvik,Bjørn Henrik Hansen

doi:10.1016/j.envres.2021.111447

Julia Farkas, Trond Nordtug + Show 8 more

Open Access

https://doi.org/10.1016/j.envres.2021.111447

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Abstract

Mining and processing of minerals produce large quantities of tailings as waste. Some countries, including Norway, allow disposal of mine tailings in the sea. In this study we investigated the impacts of tailings from a calcium carbonate (CaCO3) processing plant on early live stages of haddock (Melanogrammus aeglefinus) and Atlantic cod (Gadus morhua). Fish eggs (3 days post fertilisation; dpf) were exposed for 48 h to three concentrations of tailings, nominally 1 mg L−1 (low, L); 10 mg L−1 (medium, M) and 100 mg L−1 (high, H); with L and M representing concentrations occurring at tailing release points. Results show that tailings rapidly adhered to eggs of both species, causing negative buoyancy (sinking of eggs) in M and H exposures. While tailings remained on egg surfaces in both species also after exposure termination, adhesion seemed more pronounced in cod, leading to larger impacts on buoyancy even after exposure. Tailing exposure further induced early hatching and significantly reduced survival in M and H exposed embryos in both fish species, and in cod from the L exposure group. Moreover, tailing exposure caused reduced survival and malformations in larvae, potentially related to premature hatching. This study shows that mineral particles adhere to haddock and cod eggs, affecting egg buoyancy, survival and development.

Highlights

Several anthropogenic activities can increase suspended particle loads in marine environments, for example dredging for marine navi gation maintenance, subsea construction including the construction of offshore windfarms, run-off from agriculture, urban development, landbased mining and processing as well as subsea mining activities (Kjel land et al, 2015; Linders et al, 2018)
In the current study we investigated whether a short term (48 h) exposure to calcium carbonate (CaCO3) tailings affects early life stages of haddock (Melanogrammus aeglefinus) and Atlantic cod (Gadus morhua)
Contact times of fish eggs and mineral particles at tailing release sites are not known to our knowledge

Summary

Introduction

Mining and ore processing generate large quantities of non-useable finely grinded particulate material, so called tailings, that require disposal (Dold, 2014; Ramirez-Llodra et al, 2015). Norway is one out of eight countries worldwide that practises submarine tailing placement (STP) and several Norwegian mines, quarries and processing plants are placing their tailings into adjacent fjords (Ramirez-Llodra et al, 2015). Upwelling processes and slope failures are sources for fine particulate material into the water column, with the latter being of special concern for seabeds with steep slopes (Ramirez-Llodra et al, 2015). Despite ongoing STP, scientific data and literature on impacts on fjord ecosystems is still scarce, with knowledge on potential impacts on organisms inhabiting the water column being even less (Olsvik et al, 2015; Ramirez-Llodra et al, 2015; Skei and Syvitski, 2013)

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