Maternal transfer efficiency and transgenerational toxicity of methylmercury in <i>Daphnia magna</i>

Tsui, Martin Tsz‐Ki; Wang, Wen‐Xiong

doi:10.1897/03-310

Cited by 48 publications

(41 citation statements)

References 32 publications

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“…However, Daphnia grew faster on high-quality, low C:P algae (''Daphnia responses'' in Table 1) resulting in a significant reduction in the concentration of MeHg in their tissues. Daphnia MeHg efflux rates (Ϸ0.041 d Ϫ1 ) were consistent with those found in other studies (21,22) and were lower than the efflux rates of other heavy metals, such as Cd, Cr, Se, Zn (23), and inorganic Hg (24). Low MeHg efflux rates result in the buildup of high levels of MeHg in somatic tissue.…”

Section: Discussionsupporting

confidence: 88%

Stoichiometric controls of mercury dilution by growth

Karimi

Chen

Pickhardt

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

192

153

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Rapid growth could significantly reduce methylmercury (MeHg) concentrations in aquatic organisms by causing a greater than proportional gain in biomass relative to MeHg (somatic growth dilution). We hypothesized that rapid growth from the consumption of high-quality algae, defined by algal nutrient stoichiometry, reduces MeHg concentrations in zooplankton, a major source of MeHg for lake fish. Using a MeHg radiotracer, we measured changes in MeHg concentrations, growth and ingestion rates in juvenile Daphnia pulex fed either high (C:P ‫؍‬ 139) or low-quality (C:P ‫؍‬ 1317) algae (Ankistrodesmus falcatus) for 5 d. We estimated Daphnia steady-state MeHg concentrations, using a biokinetic model parameterized with experimental rates. Daphnia MeHg assimilation efficiencies (Ϸ95%) and release rates (0.04 d ؊1 ) were unaffected by algal nutrient quality. However, Daphnia growth rate was 3.5 times greater when fed high-quality algae, resulting in pronounced somatic growth dilution. Steady-state MeHg concentrations in Daphnia that consumed high-quality algae were one-third those of Daphnia that consumed low-quality algae due to higher growth and slightly lower ingestion rates. Our findings show that rapid growth from high-quality food consumption can significantly reduce the accumulation and trophic transfer of MeHg in freshwater food webs.contaminants ͉ food quality ͉ heavy metals ͉ nutrient stoichiometry ͉ plankton M ethylmercury (MeHg) poses a serious human and wildlife health risk primarily through fish consumption, so understanding the key factors driving MeHg accumulation in fish has become a global priority (1). Rapid somatic growth rates are hypothesized to reduce mass-specific MeHg concentration (burden) in fish and other aquatic organisms (2, 3) by the process of somatic growth dilution (SGD). SGD occurs when rapid growth results in a disproportionate increase in the net rate of biomass gain relative to MeHg gain. The relative quality of food consumed can strongly influence growth rates in aquatic organisms. Moreover, food quality for aquatic consumers varies widely across lakes and seasons (4), thus potentially contributing to the large variation in Hg concentrations observed in lake fish in situ. Despite its potential importance, the influence of food quality on MeHg accumulation has not been well examined.At present, evidence for somatic growth dilution of MeHg, whether due food quality or other factors, is sparse and somewhat contradictory. Thus far, our understanding of SGD has been limited to inferences drawn from field correlations between somatic growth rates and Hg concentrations in fish. In most of these studies, the many possible factors driving SGD (e.g., temperature, food availability, food quality, activity level, and stress) are not controlled and are often confounded. Negative correlations between somatic growth rate and concentrations of total Hg (5-8) and other contaminants, such as Pb (9

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Section: Discussionsupporting

confidence: 88%

Stoichiometric controls of mercury dilution by growth

Karimi

Chen

Pickhardt

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

192

153

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“…Tsui and Wang (2004) showed that over 70% of a 33.3 ± 1.91 μg/g body burden resulting after a 5 day dietary exposure of MeHg was eliminated over a 20 day period in Daphnia magna . The biological retention half-life was 9.07 ± 0.12 d for MeHg in that study [50]. Assuming a similar half-life in D. pulex , our results suggest that early life exposure may affect survivorship even after the body burden of MeHg is significantly reduced, especially considering the low tissue concentrations measured in the present study (1.9 ppm (ng/mg) as Hg) after the highest dose tested (1600 ng/L).…”

Section: Discussionmentioning

confidence: 91%

Effects of early life exposure to methylmercury in Daphnia pulex on standard and reduced food ration

Doke

Hudson

Dawson

et al. 2014

Reproductive Toxicology

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As a well-known eco-toxicological model organism, Daphnia pulex may also offer advantages in human health research for assessing long-term effects of early life exposures to coupled stressors. Here, we examine consequences of early life exposure to methylmercury (MeHg) under standard and reduced food ration. We exposed Daphnia for 24 h in early life to varying concentrations of methylmercury(II) chloride (0, 200, 400, 800 and 1600 ng/L) and thereafter kept Daphnia on either a standard or a reduced food ration. The data suggests an additive effect of MeHg concentration and food ration on decreasing lifespan, although MeHg concentration does not affect survival linearly. Food ration and MeHg concentration were predictive of reduced reproduction, and there is some evidence of an interaction (p = 0.048). Multi-stressor work in alternative model systems may be useful for prioritizing research, taking into account potential antagonistic, additive or synergistic effects that nutritional status may have on chemical toxicity.

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“…Tsui and Wang (2004a) also observed in D. magna that the losses due to maternal transfer of mercury ranged from 11 to 15% for inorganic form and from 32 to 41% for organic form of this metal. The same authors, evaluating only the organic form of mercury, found that maternal transfer is the second most important mechanism of loss of this metal (Tsui and Wang 2004b).…”

Section: Discussionmentioning

confidence: 99%

Arsenic toxicity to cladocerans isolated and associated with iron: implications for aquatic environments

Sales

Rietzler

Ribeiro

2016

An. Acad. Bras. Ciênc.

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Arsenic is an ametal ubiquitous in nature and known by its high toxicity. Many studies have tried to elucidate the arsenic metabolism in the cell and its impact to plants, animals and human health. In aqueous phase, inorganic arsenic is more common and its oxidation state (As III and As V) depends on physical and chemical environmental conditions. The aim of this study was to evaluate toxicity of arsenic to Daphnia similis and Ceriodaphnia silvestrii, isolated and associated with iron. The results showed differences in toxicity of As III and As V to both species. Effective concentration (EC50) mean values were 0.45 mg L -1 (As III) and 0.54 mg L -1 (As V) for D. similis, and 0.44 mg L -1 (As III) and 0.69 mg L -1 (As V) for C. ), showing synergistic effect of these substances.

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Maternal transfer efficiency and transgenerational toxicity of methylmercury in Daphnia magna

Cited by 48 publications

References 32 publications

Stoichiometric controls of mercury dilution by growth

Stoichiometric controls of mercury dilution by growth

Effects of early life exposure to methylmercury in Daphnia pulex on standard and reduced food ration

Arsenic toxicity to cladocerans isolated and associated with iron: implications for aquatic environments

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