Effects of Phosphorus and Zinc on the Neotropical Cladoceran Ceriodaphnia silvestrii by Dietary Routes

Trophic-Level Interactive Effects of Phosphorus Availability on the Toxicities of Cadmium, Arsenic, and Their Binary Mixture in Media-Exposed Scenedesmus acutus and Media and Dietary-Exposed Daphnia pulex

“…pulex. It is important to note that the low mortality we observed with dietary Cd and Cd/As mix exposures had been reported in other studies with media Cd exposures. , Similar reasons of structural analogy of oxyanaions of As and P, and competitive preferential uptake by membrane phosphate transporters may account for the increased As toxicity in LP media. − Differential toxicity of dietary metals in the grazer may also be influenced by a host of factors including the ease of release of metals from the diet, food quality, stoichiometric imbalance, ingestion rate, selective excretion of the diet prior to metal release, form in which the metal is bound in the diet, as well as the concentration and bioavailability of metals in the diet. ,− …”

“…There are studies on mixture toxicity that have reported additivity and synergism between Cd and As coupled with other metals. ,− See SI Table S9 for additional information. The lethal toxicity of heavy metals may be elicited via different mechanisms/modes of action (MOA) including the generation of ROS which may cause oxidative damage to cellular macromolecules (DNA, protein, and lipid), triggering various deleterious effects that may ultimately lead to cell death …”

“…The lethal toxicity of heavy metals may be elicited via different mechanisms/modes of action (MOA) including the generation of ROS which may cause oxidative damage to cellular macromolecules (DNA, protein, and lipid), triggering various deleterious effects that may ultimately lead to cell death. 27 Chronic Exposure Effects of Dietary Cd, As, and Cd/ As mix against D. pulex's Survival. Aquatic organisms have defense systems with several counterparts (enzymatic and nonenzymatic) that function cooperatively to detoxify ROS.…”

“…Therefore, under limited P condition, arsenate may better compete with phosphate, leading to increased passage of As across biomembranes into the organism . Also, P plays a role in the homeostatic balance of some essential trace metals (e.g., copper and zinc) that are cofactors of enzymes that are involved in the detoxification of heavy metals including As and Cd. , Hence, P limitation may directly and/or indirectly interfere with the activities of these enzymes as well as limit the formation of cellular polyphosphate bodies (PPB) that bind detoxified heavy metals, leading to differential susceptibility to metal toxicity that may include oxidative stress. These lead us to the following hypotheses: (1) interactive effects of media P availability and Cd, As, and their mixture (Cd/As mix ) affect the growth, stoichiometric quality, metal uptake, and/or bioaccumulation in S.…”

“…25 Also, P plays a role in the homeostatic balance of some essential trace metals (e.g., copper and zinc) that are cofactors of enzymes that are involved in the detoxification of heavy metals including As and Cd. 26,27 Hence, P limitation may directly and/or indirectly interfere with the activities of these enzymes as well as limit the formation of cellular polyphosphate bodies (PPB) that bind detoxified heavy metals, 26 leading to differential susceptibility to metal toxicity that may include oxidative stress. These lead us to the following hypotheses: (1) interactive effects of media P availability and Cd, As, and their mixture (Cd/As mix ) affect the growth, stoichiometric quality, metal uptake, and/or bioaccumulation in S. acutus, and (2) the toxicities of dietary-Cd, As, and Cd/ As mix against D. pulex (survival, reproduction and behavior) is modulated by media-dietary P availability with increased toxic effects under limited P condition.…”