Resolving mechanisms of toxicity while pursuing ecotoxicological relevance?

Hinton, David E.; Kullman, Seth W.; Hardman, Ron C.; Volz, David C.; Chen, Pei‐Jen; Carney, Michael W.; Bencic, David C.

doi:10.1016/j.marpolbul.2005.07.020

Cited by 80 publications

(47 citation statements)

References 138 publications

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“…This need is well met by the use of histopathology. This idea is in line with the need to relate the responses of individuals to the responses of populations and communities (Hinton et al, 2005). Measuring the relative changes of biomarkers in response to environmental and contaminant-related variables will help define the breadth of physiologic changes that can be anticipated in response to specific contaminants.…”

Section: Histopathologymentioning

confidence: 93%

Polychlorinated Biphenyl Exposure Causes Gonadal Atrophy and Oxidative Stress in Corbicula fluminea Clams

2007

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Polychlorinated biphenyls (PCBs) are widespread environmental contaminants that have been linked to oxidative and other toxic effects in both humans and wildlife. Due to recent environmental health concerns at a PCB contaminated Superfund site near Raleigh, NC, we used a common clam species (Corbicula fluminea) as surrogates to isolate the effects of PCBs on threatened bivalves native to the region. Under controlled laboratory conditions, clams were exposed to 0, 1, 10, or 100 ppb Aroclor 1260 in the ambient water for 21 days. Measured biomarkers spanned a range of effective levels of biological organization including low molecular weight antioxidants, lipid-soluble antioxidants, and whole tissue radical absorption capacity. These data were augmented by use of histological evaluation of whole samples. Aroclor 1260 significantly increased reduced glutathione (GSH) and total protein concentrations at all treatments levels. Significant decreases were measured in all treatments in γ -tocopherol and total oxidant scavenging capacity (TOSC) and α-tocopherol values in the 100 ppb exposure. Histologically, Aroclor 1260 caused significant gonadal atrophy, effacement of gonad architecture with accumulations of Brown cells, and inflammation and necrosis in digestive glands and foot processes. Our results indicate that oxidative mechanisms play a significant role in the decreased health of these clams due to exposure to Aroclor 1260. The changes in the gonads of exposed clams suggest that a serious threat to bivalve reproduction exists due to PCB exposure.

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Section: Histopathologymentioning

confidence: 93%

Polychlorinated Biphenyl Exposure Causes Gonadal Atrophy and Oxidative Stress in Corbicula fluminea Clams

2007

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“…In the context of guiding species recovery, management decisions are typically made at the scale of populations. Resolving issues of scale is a central challenge in ecotoxicology, and it extends beyond salmon to at-risk aquatic populations, communities, and ecosystems worldwide (Eggen et al 2004, Hinton et al 2005.…”

Section: Introductionmentioning

confidence: 99%

A fish of many scales: extrapolating sublethal pesticide exposures to the productivity of wild salmon populations

Baldwin¹,

Spromberg

Collier

et al. 2009

Ecological Applications

112

101

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Abstract. For more than a decade, numerous pesticides have been detected in river systems of the western United States that support anadromous species of Pacific salmon and steelhead. Over the same interval, several declining wild salmon populations have been listed as either threatened or endangered under the U.S. Endangered Species Act (ESA). Because pesticides occur in surface waters that provide critical habitat for ESA-listed stocks, they are an ongoing concern for salmon conservation and recovery throughout California and the Pacific Northwest. Because pesticide exposures are typically sublethal, a key question is whether toxicological effects at (or below) the scale of the individual animal ultimately reduce the productivity and recovery potential of wild populations. In this study we evaluate how the sublethal impacts of pesticides on physiology and behavior can reduce the somatic growth of juvenile chinook salmon (Oncorhynchus tshawytscha) and, by extension, subsequent sizedependent survival when animals migrate to the ocean and overwinter in their first year. Our analyses focused on the organophosphate and carbamate classes of insecticides. These neurotoxic chemicals have been widely detected in aquatic environments. They inhibit acetylcholinesterase, an enzyme in the salmon nervous system that regulates neurotransmittermediated signaling at synapses. Based on empirical data, we developed a model that explicitly links sublethal reductions in acetylcholinesterase activity to reductions in feeding behavior, food ration, growth, and size at migration. Individual size was then used to estimate sizedependent survival during migration and transition to the sea. Individual survival estimates were then integrated into a life-history population projection matrix and used to calculate population productivity and growth rate. Our results indicate that short-term (i.e., four-day) exposures that are representative of seasonal pesticide use may be sufficient to reduce the growth and size at ocean entry of juvenile chinook. The consequent reduction in individual survival over successive years reduces the intrinsic productivity (lambda) of a modeled oceantype chinook population. Overall, we show that exposures to common pesticides may place important constraints on the recovery of ESA-listed salmon species, and that simple models can be used to extrapolate toxicological impacts across several scales of biological complexity.

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“…As described by Gourmelon and Ahtiainen (2006), full validation by the OECD requires testing of coded compounds, including positive and negative controls (examples are provided in Table 3), for the assessment of inter-laboratory reproducibility (using a minimum of three laboratories per species). Based on current information, for example, biomarkers on endocrine disruption may be used to guide aquatic species selection, inform efficient chronic test design and concentration selection and help with in vitro and in vivo in read across between chemicals within the same class (Hutchinson 2002;Hinton et al 2005;Hutchinson et al 2006a). Compared with mammals, amphibians and fish (OECD meeting of the Endocrine Disrupters Task Force, April 2006), the development and validation of endocrine-related biomarkers for invertebrates has great potential.…”

Section: Research Recommendation 3-validation Of Mechanistic Biomarkementioning

confidence: 99%

Small is useful in endocrine disrupter assessment—four key recommendations for aquatic invertebrate research

Hutchinson

2007

Ecotoxicology

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As we enter the 21st "biocentury", with issues such as biodiversity and biotechnology growing in public profile, it is important to reflect on the immense ecological, medical and economic importance of invertebrates. Efforts to understand the diverse biology of invertebrates come from many directions, including Nobel Prize winning developmental biology, research to control insects that threaten human health and food supplies, aquaculture opportunities and also within ecotoxicology. In the latter context, this special journal volume highlights the importance of addressing endocrine disruption in aquatic invertebrates, from molecular and cellular biomarkers to population-relevant adverse effects. The contributors to this special volume have provided an excellent assessment of both the fundamental endocrinology and applied ecotoxicology of many aquatic invertebrate groups. On the premise that reproductive success is ultimately the vital population parameter, this chapter gives a personal view of key gaps in knowledge in invertebrate reproductive and developmental endocrinology and ecotoxicology. Based on current knowledge, there are four key issues that need to be prioritised within aquatic ecotoxicology: (1) a wider assessment of the reproductive status of invertebrates in both freshwater and coastal ecosystems; (2) prioritisation of laboratory studies in OECD and other regulatory test organisms, including basic endocrinology and ADME (absorption, distribution, metabolism and excretion) research; (3) development and validation of mechanistic biomarkers that can be used as "signposts" to help prioritise species and chronic test endpoint selection, and help link data from laboratory and field studies; and (4) develop a comparative invertebrate toxicology database utilising the prioritised reference chemicals from the EDIETA workshop, encompassing the diverse modes-of-action pertinent to endocrine disrupter testing in both aquatic arthropod and non-arthropod invertebrates.

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Resolving mechanisms of toxicity while pursuing ecotoxicological relevance?

Cited by 80 publications

References 138 publications

Polychlorinated Biphenyl Exposure Causes Gonadal Atrophy and Oxidative Stress in Corbicula fluminea Clams

Polychlorinated Biphenyl Exposure Causes Gonadal Atrophy and Oxidative Stress in Corbicula fluminea Clams

A fish of many scales: extrapolating sublethal pesticide exposures to the productivity of wild salmon populations

Small is useful in endocrine disrupter assessment—four key recommendations for aquatic invertebrate research

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