|MadSci Network: Environment & Ecology|
Likely a good quantity of sodium sulfide to put into distilled water would be 5 grams into 100 mL of the distilled water. If you get a black precipitate this could be considered as positive for lead, however, other things can also give a black precipitate. It would be good to have a second test to confirm the presence of lead and this would be a fun research project. One substance which also reacts with lead is often found in hardware stores in Lead Test Kits. it gives a pink or red color w/lead, but I forget its name.
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