Arsenic biota

Transmethylation is important not only in the biosynthesis of cellular components but also in detoxification. Although the resulting metabolites are less toxic to the cell, they are often more lipophilic and may have serious adverse effects on other biota. Toxic volatile arsenic compounds... 

Lethal and sublethal effects of various arsenic compounds on selected species of aquatic biota... 

Table 28.4 (continued) Lethal and Sublethal Effects of Various Arsenic Compounds on Selected Species of Aquatic Biota... 

Freshwater biota tissue residues Diminished growth and survival reported in immature bluegills (Lepomis macrochirus) when total arsenic residues in muscle are >1.3 mg/kg fresh weight (FW) or >5 mg/kg in adults (NRCC 1978)... 

Saltwater biota tissue residues Depending on chemical form of arsenic, certain marine teleosts may be unaffected at muscle total arsenic residues of 40 mg/kg FW (NRCC 1978)... 

Irgolic, K.J., W. Goessler, and D. Kuehnelt. 1998. Arsenic compounds in terrestrial biota. SEGH 3rd Inter. Conf. Arsenic Expos. Health Effects 11. 

Both arsenic and chromium are considered to pose risks to public health and, in the inorganic state, especially chromium in hexavalent form, are generally highly toxic to biota. Their toxicity to humans was evidenced by... 

Whenever Fe oxides, especially ferrihydrite, are formed in nature, a range of toxic or unwanted elements is coprecipitated. A case of natural detoxification of arsenic by Fe oxides was observed on the Coral Reef of Amberlite Island, Papua New Guinea. Upon reaching the aerobic surface waters, hydrothermal fluids rich in dissolved As and Fe, lose their As (and Fe) almost completely by adsorption on and/or coprecipitation of 2-line ferrihydrite. The precipitate contained (besides tens of mg of Cu, Pb, Zn) 55g/ kg As, and, thus, it prevented any damage to the biota (Pichler Veizer, 1999). Arsenic peaks (0.1-0.6 xM) at a depth of 2-6 cm in surficial sediments in 16 Canadian lakes were closely correlated with hydroxylamine reducible Fe (0.2-1 mM), suggesting again a close association between As and poorly ordered Fe oxides (Belzile Tes-sier, 1990). 

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