bids are invited for procurement of i) insouble matter, percent by mass, max i) soluble iron compound (as fe), percent by mass, max i) water soluble aluminium compounds (as al,o,), percent by mass, min v) ph (of 5 percent aqueous solution), min v) free acidity (as h.so), basicity (as al,o,). percent by mass, max i) lead (as pb). parts per million, max i) arsenic (as as,o,), parts per million, max ii) mercury (as hg), parts per million, max x) manganese (as mn), parts per million, max x) chromium (as cr), parts per million, max i) cadmium (as cd), parts per million, max ii) selenium (as se), parts per million, max ii) organic impurities: a) phenolic compounds (as c,h,oh), parts per million, max b) anionic detergents (as mbas), parts per million, max