A lab chemist used gravimetric analysis to determine the lead content in a pond near a battery manufacturing plant. A 500 mL sample of water from the pond was treated with an excess of sodium sulfide (Na2S) solution. If 0.2560g of lead (II) sulfide (PbS) was obtained from the sample. What was the concentration of lead in the pond? If the acceptable level is 0.001 g/L, is the water from the pond within the acceptable level?