Daily allowance mercury

When the recommended daily allowance (RDA) for calcium is not met by the diet is (particularly in women), supplementation in the form of calcium salts is recommended. Calcium salts vary widely in calcium content by weight, calcium gluconate has 9%, calcium lactate has 13%, and calcium carbonate has 40% calcium. Absorption of calcium from salts may vary calcium carbonate is the most poorly absorbed. Bone meal and dolomite are not recommended sources of calcium, since they may contain lead, arsenic, mercury, and other toxic metals. A potential complication of excessive calcium intake is formation of urinary tract stones this risk may be reduced by ample fluid intake. 

The RfDs and TDIs are often used to establish regulatory standards. Such standards usually specify a limit on the allowable concentration of a chemical in an environmental medium. The process is not difficult to understand. The RfD and its related estimates of population thresholds is a dose, typically expressed in mg/(kg b.w. day), that is considered to be without significant risk to human populations exposed daily, for a lifetime. Consider mercury, a metal for which an RfD of 0.0003 mg/(kg b.w. day) has been established by the EPA, based on certain forms of kidney toxicity observed in rats (Table 8.4). These are not the only toxic effects of mercury, but they are the ones seen at the lowest doses. Note also that we are dealing with inorganic mercury, not the methylated form that is neurotoxic. 

Large increases in mercury levels in water can be caused by industrial and agricultural use and waste releases. The health risk from mercury is greater from mercury in hsh than simply from water-borne mercury. Mercury poisoning may be acute, in large doses, or chronic, from lower doses taken over an extended time period. The maximum amount of mercury allowed in drinking water by the standard is 0.002 mg/L of water. That level is 13% of the total allowable daily dietary intake of mercury. 

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