Answer:
1. Soil and water samples for levels of DDT and its metabolites
2. Air samples for levels of DDT and its metabolites
3. Sediment samples for levels of DDT and its metabolites
4. Biological samples for levels of DDT and its metabolites
5. Surface water run-off for levels of DDT and its metabolites
6. Aquatic life for levels of DDT and its metabolites
7. Plant life for levels of DDT and its metabolites
8. Temperature and pH levels in the environment
9. Wind speed and direction
10. Rainfall levels