Activity: Managing 'heavy metal' water pollutants

ATL

• Critical-thinking skills: Gather and organise relevant information to formulate an argument; evaluate and manage risk; propose and evaluate a variety of solutions; interpret data

Dissolving substances to reduce their concentration reduces their environmental impact. In this activity you will investigate factors that affect solubility.

Inquiry question: How can a toxic, poisonous ion be detected and disposed of safely? What happens to the heavy metal waste collected in your school laboratory?

This 11-Year-Old Invented A Cheap Test Kit For Lead In Drinking Water

Safety: Work with care, using protective clothing and wash hands - heavy metals are toxic. Be sure to consider carefully how you will dispose of any reaction products. Minimise the quantities you use.

In this investigation you have two, related aims:

1. To develop a kit that can detect a 'heavy metal' of your choice dissolved in water. The kit may detect more than one type of ion, but must include the ion you are investigating.

2. To develop a method for precipitating these ions out of the solution. The remaining solution should not include the heavy metal ions.

Planning

• • Explain the general hazards caused by heavy metals. Before selecting a specific heavy metal ion for your investigation, check whether ionic compounds containing the element are available in your school.

  • Your scientific reasoning should outline examples of reactions involved in the precipitation of the heavy metal ion out of solution. Include solubility information (g dm^-3) for ionic compounds of the heavy metal you selected. Anticipate using your own 'detector kit' to evaluate the efficiency of your decontamination process in the second part of your investigation.

  • Present a list of all the chemicals you plan to use.

Analyses

Reporting your investigation: interpreting results

1. interpret your results

   1. discuss their validity (whether there could be an alternative explanation for the effects you measured) and reliability (how consistent the effects you measured were).

   2. Reporting your investigation: interpreting the science

   3. Present your results to show trends effectively.

   4. Discuss your results with reference to your method and evaluate its validity.

   5. Discuss your method, and evaluate its validity.

   6. Suggest improvements and extensions of this investigation.¹

Assessment opportunities

• In this activity you have practiced skills that can be assessed with Criterion B: Inquiring and designing and Criterion C: Processing and evaluating.

Citation:

¹Termaat, Annie. “Chapter 5.” Chemistry for the IB MYP 4 & 5, Hodder Education, London, 2016, pp. 106.