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Michael C. Mix

Bio: Michael C. Mix is an academic researcher from Oregon State University. The author has contributed to research in topics: Bay & Mytilus. The author has an hindex of 14, co-authored 25 publications receiving 663 citations.
Topics: Bay, Mytilus, Ostrea lurida, Oyster, Ecotoxicology

Papers
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Journal ArticleDOI
TL;DR: Much additional research is required before the relationship(s) between environmental pollution and neoplasms in indigenous aquatic species can be understood, and the current state of knowledge in the general areas of fish and shellfish metabolism and the use of aquatic animal models in studies of chemical carcinogenesis is described.

191 citations

Journal ArticleDOI
TL;DR: The effects of depuration, size and sex on the concentrations of Mn, Ni, Cu, Zn and Cd were determined for gonadal and somatic tissues of Mytilus edulis from Yaquina Bay, Oregon.

97 citations

Journal ArticleDOI
TL;DR: Results suggest that somatic and gonadal tissue should be considered separately when measuring metal levels, while somatic burdens of nickel, manganese, and zinc were maximal in early spring, while copper, cadmium and vanadium fluctuated without regard to gametogenesis or spawning.
Abstract: Levels of six trace metals were measure in Mytilus edulis during a six month period. Patterns of seasonal variation were established and normal ranges of metal burdens in mussels were determined. Metals measured were vanadium, manganese, nickel, copper, zinc and cadmium. Sexually mature M. edulis, between 50 and 60 mm in size, were sampled in Yaquina Bay, Oregon at regular intervals between October 1979 and June 1980. Tissues were combined in two pools, ''somatic'' and ''gonadal''. Flame atomic absorption was used to determine concentrations of manganese, nickel, copper, and cadmium. Vanadium was determined by neutron activation analysis. With the exception of copper, all gonadal tissue burdens were greatest in late winter or early spring, at the time of gametogenesis. Somatic burdens of nickel, manganese, and zinc were maximal in early spring, while copper, cadmium and vanadium fluctuated without regard to gametogenesis or spawning. Zinc concentrations increased dramatically between days 22 and 80. Such increases may be indicative of the onset of gametogenesis. Results suggest that somatic and gonadal tissue should be considered separately when measuring metal levels. 1 table (JMT)

49 citations

Journal ArticleDOI
TL;DR: The pattern of naphthalene uptake and accumulation in oyster tissues was relatively constant and was shown to be a function of multiple variables such as nutritional state, lipid concentration, length of exposure to nphthalene, and the external nAPHthalene concentration.
Abstract: A flow-through system was used to follow naphthalene and naphthalene metabolite accumulation in the seawater and in the tissue of the oyster Ostrea edulis. After 72 h, 82.5% of the naphthalene carbon was recovered from the system. Glucose was added to seawater to stimulate the pathways of glucose metabolism in the oysters. Streptomycin (100 ppm) reduced microbial oxidation of naphthalene and glucose, and reduced bacterial growth. However, even in the presence of streptomycin, microbial oxidation of naphthalene was considerable. The main oxidation product recovered from seawater was 14CO2. Radioactivity was also associated with compounds which separated by TLC with 2- and 1- naphthol. The pattern of naphthalene uptake and accumulation in oyster tissues was relatively constant after only a few hours of exposure to naphthalene. The potential of tissues to accumulate naphthalene was shown to be a function of multiple variables such as nutritional state, lipid concentration, length of exposure to naphthalene, and the external naphthalene concentration. Carbon-14-labeled metabolites derived from 14C-naphthalene were consistently recovered from digests of the oyster tissues. Non-CO2 alkaline-soluble substances were the primary metabolites. Hexane-extractable substances, which separated by TLC with known standards of 2- and 1- naphthol, were consistently recovered from seawater and tissue digests. It was not possible to conclude that these metabolites were a result of naphthalene metabolism by oyster enzyme systems.

31 citations

Journal ArticleDOI
TL;DR: The large Mytilus edulis cells possess many ultrastructural properties that are characteristic of certain malignant vertebrate cells, however, alternative explanations for their structure and function are also possible.

30 citations


Cited by
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Journal ArticleDOI
TL;DR: There is little doubt that measurements of bioaccumulation and biomarker responses in fish from contaminated sites offer great promises for providing information that can contribute to environmental monitoring programs designed for various aspects of ERA.

4,397 citations

Journal ArticleDOI
TL;DR: In this paper, the edge zone microenvironmental gradients were described at ten edge sites in southeastern Pennsylvania and northern Delaware, USA, where sites were selected to allow comparisons of edge orientation and successional development, and significant edge effects were detected in light, temperature, litter moisture, vapor pressure deficit, humidity, and shrub cover.

684 citations

Journal ArticleDOI
TL;DR: A selection of biomarkers of stress, genotoxicity and exposure usually employed in biomonitoring programmes is presented, together with a brief overview of new biomolecular approaches.
Abstract: The paper outlines a 2-tier approach for wide-scale biomonitoring programmes. To obtain a high level of standardization, we suggest the use of caged organisms (mussels or fish). An "early warning", highly sensitive, low-cost biomarker is employed in tier 1 (i.e. lysosomal membrane stability (LMS) and survival rate, a marker for highly polluted sites). Tier 2 is used only for animals sampled at sites in which LMS changes are evident and there is no mortality, with a complete battery of biomarkers assessing the levels of pollutant-induced stress syndrome. Possible approaches for integrating biomarker data in a synthetic index are discussed, along with our proposal to use a recently developed Expert System. The latter system allows a correct selection of biomarkers at different levels of biological organisation (molecular/cellular/tissue/organism) taking into account trends in pollutant-induced biomarker changes (increasing, decreasing, bell-shape). A selection of biomarkers of stress, genotoxicity and exposure usually employed in biomonitoring programmes is presented, together with a brief overview of new biomolecular approaches.

630 citations

Journal ArticleDOI
TL;DR: In this paper, the distribution of polycyclic aromatic hydrocarbons (PAHs) has been investigated in superficial sediments and mussels (Mytilus galloprovincialis) of the western Mediterranean sea (French Riviera, Corsica, Sardinia).
Abstract: The distribution of polycyclic aromatic hydrocarbons (PAHs) has been investigated in superficial sediments and mussels (Mytilus galloprovincialis) of the western Mediterranean sea (French Riviera, Corsica, Sardinia). The analyses were performed by gas chromatography coupled to mass spectrometry (GC-MS). The PAH concentrations ranged from 1 to 20,500 ng/g in the sediments. Different molecular indices allowed differentiation between the different pollutant sources. On the French coast, PAHs originated mainly from incomplete combustion of organic matter (pyrolytic origin), whereas for some sites in Corsica and Sardinia an overimposition of petrogenic PAHs occurred. The mussel PAH concentrations ranged from 25 to 390 ng/g. The total and individual PAH bioaccumulation factors were calculated. The correlation between sediment and mussel PAH content was discussed in terms of bioavailability. It was possible to distinguish different absorption routes for the xenobiotics according to their physicochemical properties. Because the mussel distribution of phenanthrene and anthracene seems to be governed by their water solubility, these compounds were probably mainly absorbed as the water-dissolved form, whereas the heavier molecular weight PAHs (more than four aromatic rings), whose sediment and mussel concentrations are correlated with higher correlation coefficients than for phenanthrene and anthracene, were probably mainly absorbed as adsorbed on particles. Furthermore, a possible preferential biotransformation of benzo[a]pyrene over benzo[e]pyrene is discussed.

615 citations

Book ChapterDOI
TL;DR: Partitioning of combustion-derived PAHs between water and sediment may be much less than predicted, possibly because associations with particles are much stronger than expected, and this reduced partitioning may produce erroneous results in predicting bioaccumulation where uptake from water is important.
Abstract: Polycyclic aromatic hydrocarbons (PAHs) appear in most urbanized coastal areas of the world, accumulating in sediments and biota that are unable to efficiently eliminate them. This review focuses specifically on the mechanisms of bioavailability, uptake, and elimination, which determine the extent of accumulation and retention of PAHs in invertebrates and fish in marine ecosystems. We review here the literature on the mechanisms and factors that control these processes which ultimately determine the concentration of PAHs in marine organisms. Understanding both the temporal and spatial characteristics of bioaccumulation of the environmentally important PAHs is crucial for determining the impact that this class of compounds may have on marine populations. To provide a complete assessment of these potential impacts, scientists require knowledge about the distribution of these compounds in different environmental matrices, their uptake and partitioning in different tissues, their rates of elimination, and their potential for persistence in certain species. The combined information on these mechanisms and the environmental factors that control accumulation will help scientists develop predictive models of contaminant accumulation both for acute events, such as oil spills, and for long-term, chronic exposure as is found in many urban areas in our coastal ecosystems.

599 citations