Mechanisms of Cadmium Toxicity To Various Trophic Saltwater Organisms

Mechanisms of Cadmium Toxicity to Various Trophic Saltwater Organisms

Introduction Metal pollution of the marine environment is a major problem of increasing magnitude that has become an issue of concern, because most of the metals are transported into the marine environment and accumulated without decomposition. GESAMP (the joint Group of Experts on the Scientific Aspects of Marine Pollution) defined marine pollution as "introduction by […]

Sources and Pathways of Cadmium in the Environment Part 1

As already noted, cadmium may be present in the environment both from natural and anthropogenic sources. It occurs mainly as a component of minerals in the earth’s crust at an average concentration of 0.18 mg/kg and usually ranges from approximately 0.01 to 1.8 mg/kg in soils. In natural freshwaters, cadmium can occur at concentrations below […]

Sources and Pathways of Cadmium in the Environment Part 2

Speciation and Bioavailability of Cadmium in Aquatic Environment The free cadmium cation [Cd2+] has been shown to be the most bioavailable and toxic form of the metal for many aquatic organisms, which means that its bioavailability and toxicity is diminished when cadmium becomes associated with particulate matter or forms of inorganic or organic complexes. Bioaccumulation […]

Toxicity of Waterborne Cadmium to Saltwater Aquatic Organisms Part 1

Cadmium is a relatively rare element that is a minor nutrient for aquatic organisms at low concentrations, but is toxic to aquatic biota at concentrations only slightly higher. In aquatic environments, organisms are exposed to cadmium in dissolved and particulate-bound forms, including ambient water, sediments, and food (Figure 7). Cadmium can be taken up by […]

Toxicity of Waterborne Cadmium to Saltwater Aquatic Organisms Part 2

The Role of Metal-Binding Proteins, Metallothioneins (MTs) Metallothioneins (MTs) are heat-stable, metal-binding proteins of low molecular weight (ca. 7 kilodaltons), high cysteine content (ca. 30%), and no aromatic amino acids. They occur throughout the animal kingdom as well as in plants, and are located mainly in the cytosol or in the nucleus, the amounts of […]

Toxicity of Dietary Cadmium to Aquatic Organisms Part 1

Regulatory assessments of cadmium toxicity are originally mostly based on dissolved cadmium concentrations with the assumption that toxicity is caused by dissolved (or waterborne) cadmium only, and does not include the possible impact of cadmium associated with the particulate phase (e.g., phytoplankton, suspended particulate matter, sediment; food particles = dietary exposure). In recent years, more […]

Toxicity of Dietary Cadmium to Aquatic Organisms Part 2

Mechanism of Cadmium to Microalgae Cadmium uptake is described in terms of two distinct steps that are believed to occur when cadmium cations are taken from solution by living algal cells: an initial rapid uptake of [Cd2+] due to attachment to the cell wall, followed by a relatively slow uptake due to membrane transport of […]

Environmental Safety of Cadmium

Sensitivity differences within these "target" groups are often described by statistical distributions using the species sensitivity distributions (SSDs) concept (Figure 15). In this figure, acute cadmium saltwater toxicity data were available for 61 species. Toxicity values ranged from 41.3 ^g/L for the Mysid to 135 mg/L for an oligochaete worm. Copepods appeared to be the […]

Conclusion (Mechanisms of Cadmium Toxicity To Various Trophic Saltwater Organisms)

Cadmium inputs to the estuarine and marine environment as a probable carcinogen are derived from both natural and anthropogenic sources. The cadmium contents in the estuarine, coastal and marine waters varied between 4.4 and 5.0 g/L, and a maximum of 10.3 ^g Cd/L cadmium has been reported in the Changjiang estuary, China. Both acute and […]

Perspectives (Mechanisms of Cadmium Toxicity To Various Trophic Saltwater Organisms)

Cadmium probably manifests their toxic effects by eliminating some species and not affecting others in natural aquatic systems, which seems important to determine which species are most likely to be eliminated. Those species are the useful indicators of cadmium effects and the drivers of how ecosystems will change in response to cadmium contamination. Such information […]

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