Metal concentrations in fish otoliths in relation to body composition after laboratory exposure to mercury and lead

Abstract

Metal concentrations in fish otolithsABSTRACT Juvenile sand g o b~e s Pomatosch~stus mlnutus, plaice Pleuronectes platessa, and sole Solea solea were exposed to high or low levels of mercury or lead for 45 d In the laboratory Points on the otollth corresponding to the core (pre-treatment), the start of exposure, midway through the exposure, and the termmation of exposure were sampled and analysed by laser ablat~on -inductively coupled plasma mass spectrometry (LA-ICPMS) There were significant Increases In the metal content of the goby and sole otoliths after exposure to mercuiy or lead, and the differences between the treatment levels for each element weie significant Plaice otol~ths showed little increase in metal accumulat~on, and the difference between treatments was not sign~ficant The relationship between exposule level, otolith metal concentration, and the metal concentration in flsh muscle t i s s u~ was complex In general, lead accumulated faster in the otolith and uptake was higher at low exposuic levels Mercury concentlations in fish tissue generally paralleled the concentration measured in the otoliths and the exposure level Lead concentratlons in f~s h otol~ths were inversely related to t~s s u e concentratlons KEY WORDS: Otolith microchemistry . Heavy metals . Otollth composition INTRODUCTIONFish otoliths are composed primarily of calcium carbonate formed by the accumulation of crystals on an organic matrix. During formation, trace levels of numerous other elements are incorporated ~n t o either the organic or inorganic portion of the otolith. The concentrations of these trace elements are thought to be influenced pr~marily by the environmental conditions experienced by the fish. For example, variations in the ratios of strontium to calcium (Radtke & Targett 1984, Radtke 1989, Radtke & Shafer 1992, iron to calcium (Gauld~e et al. 1980), and the oxygen isotopes 1 6 0 to "0 (Kalish 1991b, Iacumin et al. 1992 have been linked to variations in water temperature experienced by the fish. Changes in these ratios have also been used to demonstrate the migratory patterns of anadramous and estuarine-dependent fishes (Nelson et al. 1989, Lecomte-Finiger 1992, Northcote et al. 1992, Secor 1992, Thorrold et al. 1997. Cyclic variations in the trace element composition across otolith sections have been used to verify ageing by comparison with visible annuli (Radtke & Targett 1984, Seyama et al. 1991, Radtke et al. 1993. Radioisotope ratios have also been measured to determine the age of otolith cores and thus verify ages determined by visual bands, or to determine longevity in certain species (Campana et al. 1990, 1993, Fenton & Short 1992, Kalish 1993.More detailed studies of otolith composition have made use of analytical techniques with very low detection limits for a wide range of elements. These studies have demonstrated that otoliths naturally contain many trace elements, including heavy metals, and that there are consistent differences in the composition of the otoliths for fish inhabiting different areas....

Bioaccumulation of zinc in Rana tigrina in different aquatic habitats

“…It may be concluded that the R. tigrina of low weight or small size may have gotten their food from the soil having high concentration of zinc. Similar trend of metals accumulation in fish was studied by Geffen et al (1998). They found that tissue concentration of some metals declined exponentially with fish size.…”

Trace metal incorporation in otoliths of a territorial coral reef fish (Abudefduf saxatilis) as an environmental monitoring tool

“…Mercury belongs to the group of elements that induces metallothionien production, which detoxifies the metal (Pulsford et al, 1992). On this way, some studies have revealed that high and prolonged exposure can overwhelm the defense mechanisms, and excretion may not keep pace with accumulation (Wang and Wong, 2003); thus mercury remained available for incorporation in the otolith, and its incorporation would reflect both concentration and exposure level, like other authors have reported (Geffen et al, 1998). At the same time, some studies found that the Pb and Cd otoliths content, are more likely related to the fish environment than to physiological processes, and their concentrations are associated with anthropogenic sources and is not correlated with pH, salinity or other environmental factors (Köck et al, 1996;Ranaldi and Gagnon, 2008a).…”

“…Numerous studies have used otolith microchemistry for stock discrimination, migratory studies, and connectivity (see Thorrold and Swearer, 2009), but only a few studies have investigated the ability of otoliths to record exposure to pollution, either directly in terms of potentially toxic elements (Geffen et al, 1998, Milton et al 2000, Ranaldi and Gagnon 2009, or indirectly as proxies for exposure along a pollution gradient (Hanson andZdanowicz, 1999, Ranaldi andGagnon 2008a).…”

Application of laser ablation ICPMS to trace the environmental history of chum salmon Oncorhynchus keta

“…Higher Sr:Ca values appear to be associated with the species that enter freshwater with well-developed eggs and spawn (breeding) quickly, such as O. keta, while the lower values are associated with fish that enter rivers with incompletely developed eggs and reside in freshwater from several to many months before spawning, such as freshwater-resident salmon, e. g. sockeye salmon, rainbow trout and chinook salmon. Recent laboratory experiments revealed a clear relationship between the concentration of trace metals in otoliths and the environment (Geffen et al, 1998;Bath et al, 2000;Milton and Chenery, 2001). Milton and Chenery (2001) found that the Sr:Ca, Ba:Ca and Cu:Ca ratios in the otoliths of barramundi Lates calcarifer were positively correlated with the water ratios.…”

“…The technique combines the low detection limits and wide dynamic range. Geffen et al (1998) showed that the uptake of mercury and lead into sand goby Pomatoschistus minutus and sole Solea solea otoliths was related to the water concentrations of these metals. Bath et al (2000) conducted experiments with the spot Leiostomus xanthurus that demonstrated a positive relationship between the Sr:Ca and Ba:Ca ratios in the otolith and in the water.…”