What does Heavy metal totals as Pb mean?

"Heavy metal totals as Pb" refers to the concentration of heavy metals in a sample, expressed in terms of lead (Pb) equivalents. This measurement is often used in environmental science and toxicology to assess contamination levels, as lead is a common and concerning heavy metal. It helps indicate the overall presence of various heavy metals, allowing for a standardized comparison based on lead's known toxicity and regulatory limits.