May be associated with the presence of sodium in drinking water when present in high concentrations. Often from saltwater intrusion, mineral dissolution, industrial and domestic waste. Deteriorates plumbing, water heaters, and municipal water-works equipment at high levels.
Cost basis is the original price paid for shares of a security plus or minus certain adjustments required by applicable tax rules such as adjustments with respect to reinvested distributions and sales charges.
Cost basis is important for tax purposes because it is part of the calculation used to determine the amount of capital gain or loss when the asset is sold (either by you, your heir, or donation recipient), and its holding period.