According to Standard Methods, water samples suspected to be high in heavy metals should be collected in a sample containing a chelating agent to reduce metal toxicity.

According to Standard Methods, water samples suspected to be high in heavy metals should be collected in a sample containing a chelating agent to reduce metal toxicity.

• A. True
• B. False
• C. It depends on the metal
• D. They should never contain chelating agents

Answer: (A)

The main idea here is preserving metals in a water sample so their measured amount reflects what was there when collected. A chelating agent binds metal ions, forming stable complexes that keep them dissolved and prevent changes like sticking to bottle walls or precipitating out. This stabilization helps maintain the dissolved metal concentration during storage and transport, which is crucial for accurate analysis. The chelation also reduces the metals’ reactivity, which can lower hazards during handling, but the primary goal is analytical preservation rather than hazard control. Therefore, using a chelating agent in samples suspected of containing high levels of heavy metals aligns with Standard Methods, making the statement correct.

The main idea here is preserving metals in a water sample so their measured amount reflects what was there when collected. A chelating agent binds metal ions, forming stable complexes that keep them dissolved and prevent changes like sticking to bottle walls or precipitating out. This stabilization helps maintain the dissolved metal concentration during storage and transport, which is crucial for accurate analysis. The chelation also reduces the metals’ reactivity, which can lower hazards during handling, but the primary goal is analytical preservation rather than hazard control. Therefore, using a chelating agent in samples suspected of containing high levels of heavy metals aligns with Standard Methods, making the statement correct.