Acute and long-term manganese exposure and subsequent accumulation in relation to idiopathic blindness in the American lobster, Homarus americanus

Publication date: Available online 4 December 2019Source: Aquatic ToxicologyAuthor(s): Addison T. Ochs, Jeffrey D. Shields, Gary W. Rice, Michael A. UngerAbstractManganese (Mn) is a hypoxic reactive metal commonly found in marine sediments. Under hypoxic conditions the metal becomes fully reduced to Mn2+ and is biologically available to the benthic community for uptake. Mn is also a potent neurotoxin and it may play a role in the etiology of idiopathic blindness that has been observed in American lobsters. An acute study was designed to expose American lobster, Homarus americanus, to 0, 20, 80, 150, and 300 mg L-1 (ppm) for 96 hrs to explore disparities in Mn accumulation among several tissues: optic nerve, brain, hepatopancreas, muscle, hemolymph, gill, and exoskeleton. These concentrations were based on realistic pore-water concentrations (20 mg L-1), high sediment concentrations (80 mg L-1), and unrealistically high concentrations to determine lethality (150 and 300 mg L-1). A positive correlation between Mn accumulation and exposure concentration was observed in all tissues examined. In the internal tissues, manganese concentrations showed a high affinity towards brain, optic nerve, and hemolymph. In the exoskeleton and gills, Mn concentrations were also high, possibly because of internal uptake as well as external adsorption. Concentrations of Mn in tissues from the acute exposure study followed the pattern: hemolymph > gill > exoskeleton > ...
Source: Aquatic Toxicology - Category: Toxicology Source Type: research