Methylmercury uptake and distribution kinetics in sheepshead minnows, Cyprinodon variegatus, after exposure to CH₃Hg‐spiked food

Abstract

The distribution kinetics of methylmercury (CH3Hg[II]) was determined in sheepshead minnows (Cyprinodon variegatus) after a single dose of different CH3Hg(II)-spiked food to determine what factors influence the bioavailability, uptake, and redistribution of CH3Hg(II) to various organs of C. variegatus. The kinetics of CH3Hg(II) distribution was measured in the different organs during a period of 0.1 to 35 d after dosage. The CH3Hg(II) distribution kinetics in the different tissues was modeled using a simple multicompartmental pharmacokinetic model, which assumed that blood was the conduit linking the CH3Hg(II) exchange between the different organs. The CH3Hg(II) was taken up into the intestinal tissue within hours after feeding, followed by a slow release to the blood and the other organs of the body. Exchange between the blood and the visceral organs was relatively slow, with maximum CH3Hg(II) uptake in the liver and gill occurring at 1.5 d following dietary exposure. Subsequently, the majority of the CH3Hg(II) was channeled from the viscera to the rest of the body with a substantial lag time after feeding. However, the rate of transfer between tissues in the studies reported here were faster than those measured by others for larger fish.

Relative importance of direct and trophic uranium exposures in the crayfish Orconectes limosus: Implication for predicting uranium bioaccumulation and its associated toxicity

“…Evidence was seen of trophic transfer of uranium to gills, and this was certainly linked to physiological properties (highly perfused organ) and participation in excretory metabolism [45]. Accumulation in the gill after metal trophic transfer was observed in fish [8,25,46], and in the crustacean [2,47,48]. The transport via hemolymph may, however, be low.…”

Mercury distribution in key tissues of fish (Liza aurata) inhabiting a contaminated estuary—implications for human and ecosystem health risk assessment

“…Furthermore, muscle tissues have been suggested to act as a sink for methylmercury. 52 Methylmercury is incorporated in fish muscle and brain tissue, most likely by forming a methylmercury-cysteine complex. 53 This mechanism is particularly important in the brain since this complex mimics the behaviour of normal endogenous substrates, utilizing transport systems inherent to the blood-brain barrier (BBB) to gain access to the central nervous system (CNS).…”

Methylmercury accumulation, histopathology effects, and cholinesterase activity alterations in medaka (Oryzias latipes) following sublethal exposure to methylmercury chloride

“…Therefore, the widespread vacuolation of the liver might be a common response in fish hepatocyte to various chemical stressors, which indicates a higher hepatocellular lipid, water and/or glycogen content. Using sheepshead minnows (Cyprinodon variegates) as model for investigation of MeHg uptake and distribution kinetics, Leaner and Mason (2004) reported that exchange between the blood and the internal organs was relatively slow, with maximum MeHg uptake in the liver and gill occurring at 1.5 d following dietary exposure, which exemplified that fish's liver and gill were common target of aquatic pollutant's action. By treating the snake head fish (Channa punctatus) with a sublethal concentration (0.3 g/mL) of mercuric chloride over a period of 30 days, Sastry and Gupta (1978) observed, especially between 15 and 30 days of treatment, significant pathological changes produced in the fish's liver, including liver cord disarray, connective tissue damage, granulation and vacuolation of the cytoplasm, and hypertrophy of the nucleus, necrosis, fatty infiltration, proliferation of connective tissue, glycogen depletion, and cirrhosis.…”