Diffusive Milli-Gels (DMG) for in situ assessment of metal bioavailability: A comparison with labile metal measurement using Chelex columns and acute toxicity to Ceriodaphnia dubia for copper in freshwaters

Michel Perez , S.L. Simpson , Gaetane Lespes (1) , J.J. King , M.S. Adams , C.V. Jarolimek , Bruno Grassl (1) , Dirk Schaumlöffel (1)

1 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux

Fluctuations in concentrations of bioavailable metals occur in most natural waters. In situ measurements are desirable to predict risks of adverse effects to aquatic organisms. We evaluated Diffusive Milli-Gels (DMG), a new in situ passive sampler, for assessing the bioavailability and toxicity of copper in waters exhibiting a wide range of characteristics. The performance was compared to an established Chelex-column method that measures labile copper concentrations by discrete sampling, and the ability to predict acute toxicity to the cladoceran, Ceriodaphnia dubia. The labile copper concentrations measured by the DMG and Chelex-column methods decreased with increasing dissolved organic carbon (DOC) (1.9–15 mg L−1) and hardness (21–270 mg CaCO3 L−1 hardness), with 20–70% of total dissolved copper being present as labile copper. Toxicity decreased with increasing DOC and hardness. Strong linear relationships existed between the EC50 for C. dubia and DOC, and when the EC50 was related to either the labile copper concentrations measured by DMG (r2 = 0.874) or the Chelex column (0.956) methods. The study demonstrates that the DMG passive sampler is a relevant tool for the in situ assessment of environmental risks posed by metals whose toxicity is strongly influenced by speciation. © 2016 Elsevier Ltd

Mots clés: Aquatic organisms; Bioavailability; Bioavailable metals; Biochemistry; Calcium carbonate; Carbon; Ceriodaphnia dubia; copper; Dissolved organic carbon; Gels; Hardness; Labile copper concentrations; Linear relationships; Metal bioavailability; Metals; Organic carbon; Passive sampling; Risk assessment; Sampling; Total dissolved copper; Toxicity; Water analysis

Domaines: Chimie

Michel Perez, S.L. Simpson, Gaetane Lespes, J.J. King, M.S. Adams, et al.. Diffusive Milli-Gels (DMG) for in situ assessment of metal bioavailability: A comparison with labile metal measurement using Chelex columns and acute toxicity to Ceriodaphnia dubia for copper in freshwaters. Chemosphere, 2016, 164, pp.7--13. ⟨10.1016/j.chemosphere.2016.08.006⟩. ⟨hal-01495523⟩