Microcystin-LR concentration in aquatic food web compartments from lakes of varying trophic status

Abstract

Abstrsd: Micmcystin-LR (MC-LR) wncen&&ns were examined in water, phytoplankton, invertebrates, and two fishes for up to 3 years in four cmtral Alberta lakes spanning a tmphic gradient in total phosphorus from I5 to over 500 pgL-' in epilinmetic waters MC-LR was not detected by HPLC in phytoplankton tinm an oligo-mesotmphic lake, was less than 150 ng cellular totiml-' of lake water in a eutmphic-bypereatmphic lake, and was up to M)(H) and I I 000 ngL-' in two hypenubophic lakes. MC-LR in phytoplankton was strongly correlated with the abundance of the cyanobacterium Micm~stir oeruginosa, and with aqueous micmcystin concsntration. determined by protein phosphatase bioassay (r = 0.83). MC-LR was also detected in moplankton (up to 67 pgg-' ofbiomass) and MC-LR concenti~ in zooplankton and~phytoptankton were correlated (r = 0.69). Although nine groups of macroinvertebrates were analyzed, MC-LR was only detected in gastmpods (up to 120 pgg-'1. MC-LR appears te be bansferred to invertebrates through grazing activity. MC-LR was not detected in the liven ofnmthem pike (Esox luciw) and white sucker (CawfomuE mmmermni) ~llectcd from one lake containing toxinproducing phymplankton. Accumulation of MC-LR in aquatic fwd webs appears to -in the primary consumer with probable tmnsfer of the toxin to higher trophic levels. Rhm6: Pendant UM p&ode atteigmnt une d& de 3 ans, on a mesurl les concentrations de micrwystine-LX (MC-LR) dam l'eau et le phytoptancton ainsi que chez tes inv&btis et chek dew esp&s de poissons de 4 lacs du centre de I'Alber+a 06 le gradient tmphique de phosphors total Cpilim&tique allait de 15 B phrs de 500 pgL-'. La HPLC du phytoplancton du tat oIigom6sotmphe n'a pas mis en tvidence de MC-LR; la concentration de la toxine allulaire etait inf&ieae g 150 ng.L-' d'eau dam le lac eutrophe-hypereutmphe et elk atteignait 6000 et I1 000 ngL-' dam Ies deux hypereutmphes. Par aillew, on a not6 une forte cotitation entre la concentration de MC-LR phytoplmctcmique et t'abor&xe de la cyan&&de Micmcystir ~eruginma et la concenbaticnrde micnxystine aquewse, do&e avec une pmt6ine-phospbatas.c (r= 0,83). Dn a aussi d6tectC de la MC-LR chez le moplancton (jusqu? 67 pgg-' de biomassc) et observt une con&tion entre Ia concentrations de MC-LR zwptanctonique et phytoplmctonique (r = 0.69). On a anaIys& neufgmupes de macroiwe&&s. mais la MC-LR n'a 6tC detect6 que chez les gast6mpodes (jusqu'& I20 vgg-'). La MC-LR semble passeraux invert&b& par le tmutage. On "'en a pas d6tectt dam le foie du bmche @ox /ucim) et du meunier noir (Caxmmw commermnz]~r&v6s dam l'un des lacs oti le phytoplaneton est pmdwteti de toxine. La bioconcentation de MC-LR dans lea r6seaux tmphiques aquatiques sable survenir au niveau des consommatews primaires et il y a probablement tmnsfen de la toxine auxnivcaux tmphiques plus tleds. frmduit par la R&ction]

Quantitatively evaluating detoxification of the hepatotoxic microcystin-LR through the glutathione (GSH) pathway in SD rats

“…For instance, the median lethal dose (LD 50 ) of MC-LR via intraperitoneal (i.p.) injection is approximately 50-60 μg/kg body weight (BW) in mice (Botes et al 1984;Carmichael et al 1988) and 72 and 122 μg/kg BW for fasted and fed rats (Miura et al 1991), respectively, but increases to 300-550 μg/kg BW in common carp (Cyprinus carpio) (Råbergh et al 1991), to 400-500 μg/ kg BW in rainbow trout (Oncorhynchus mykiss) (Tencalla et al 1994;Kotak et al 1996) and even to 1500 μg/kg BW in perch (Pera fluviatilis) (Ibelings et al 2005). Nevertheless, so far, there is no literature on simultaneous quantification of MC-LR and its two main metabolites and the GSH detoxification dynamics of MCs in mammals, and the role of GSH in the detoxification of MCs in mammals remains largely unknown.…”

Why mammals more susceptible to the hepatotoxic microcystins than fish: evidences from plasma and albumin protein binding through equilibrium dialysis

“…For example, half lethal dose (LD 50 ) of MC-LR via intraperitoneal injection (i.p.) is approximately 50-60 lg/ kg body weight (BW) in mice (Botes et al 1984;Carmichael et al 1988), but increases to 300-550 lg/kg BW in common carp (Cyprinus carpio) (Råbergh et al 1991), to 400-500 lg/kg BW in rainbow trout (Oncorhynchus mykiss) (Tencalla et al 1994;Kotak et al 1996) and even to 1,500 lg/kg BW in perch (Pera fluviatilis) (Ibelings et al 2005). The use of radioactive labeled MCs as a tracer through i.p.…”

Tissue distributions and seasonal dynamics of the hepatotoxic microcystins-LR and -RR in a freshwater snail (Bellamya aeruginosa) from a large shallow, eutrophic lake of the subtropical China

“…So far, there have been only occasional reports on the presence of microcystin contamination in wild aquatic animals, such as fish (Magalha`es et al, 2001;Zimba et al, 2001;Mohamed et al, 2003), mussels (Watanabe et al, 1997) and snails (Kotak et al, 1996;Zurawell et al, 1999;Ozawa et al, 2003). Such studies are still lacking in China where most freshwaters are at a high risk to toxic cyanobacterial blooms but freshwater fisheries are almost equally important as marine fisheries to Chinese consumption.…”