Pesticide ResidueUpstream water sample 1Upstream water sample 2Downstream water sampleAtrazine0.30.52.1Glyphosate1.21.44.8Chlorpyrifos0.10.21.7Malathi...
GMAT Information and Ideas : (Ideas) Questions
| Pesticide Residue | Upstream water sample 1 | Upstream water sample 2 | Downstream water sample |
|---|---|---|---|
| Atrazine | 0.3 | 0.5 | 2.1 |
| Glyphosate | 1.2 | 1.4 | 4.8 |
| Chlorpyrifos | 0.1 | 0.2 | 1.7 |
| Malathion | 0.1 | 0.2 | 0.8 |
| 2,4-D | 0.2 | 0.3 | 0.9 |
Environmental scientist Dr. Marcus Torres conducted water quality testing along the Clearwater River to identify the source of agricultural pollution affecting local ecosystems. Using liquid chromatography-mass spectrometry, his team measured pesticide concentrations at two upstream locations and one downstream location near reported fish kills. The team's analysis revealed that a specific agricultural operation between the upstream and downstream sampling points was significantly intensifying pesticide contamination levels in the river system.
Which choice best describes data from the table that support the team's conclusion?
Atrazine and glyphosate were detected at both upstream locations and at the downstream location.
Malathion and 2,4-D showed relatively smaller increases from upstream to downstream locations.
Atrazine and glyphosate showed the most dramatic concentration increases from upstream to downstream.
Chlorpyrifos showed the highest absolute concentration at the downstream location.
Step 1: Decode and Map the Passage
Part A: Create Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| "Environmental scientist Dr. Marcus Torres conducted water quality testing along the Clearwater River to identify the source of agricultural pollution affecting local ecosystems." |
|
| "Using liquid chromatography-mass spectrometry, his team measured pesticide concentrations at two upstream locations and one downstream location near reported fish kills." |
|
| "The team's analysis revealed that a specific agricultural operation between the upstream and downstream sampling points was significantly intensifying pesticide contamination levels in the river system." |
|
Part B: Provide Passage Architecture & Core Elements
Main Point: Dr. Torres's study concluded that an agricultural operation between upstream and downstream sampling points was significantly increasing pesticide contamination in the Clearwater River.
Argument Flow: The passage establishes a water quality study designed to identify pollution sources, describes the testing methodology at multiple river locations, and presents the key finding that a specific agricultural operation is significantly intensifying pesticide contamination levels.
Step 2: Interpret the Question Precisely
What's being asked? Which data from the table supports the team's conclusion about agricultural operation significantly intensifying contamination.
What type of answer do we need? Specific evidence from the data table that demonstrates significant intensification of pesticide levels.
Any limiting keywords? Content Genre: Sciences, Content Format: Text + Data Table, Question Type: Others, Language Complexity: Moderate
Step 3: Prethink the Answer
- The team concluded that an agricultural operation was significantly intensifying contamination levels
- We need to look at the data and identify which pesticides show the most dramatic evidence of this intensification - meaning the biggest jumps from upstream to downstream concentrations
- The right answer should identify the pesticides that showed the most dramatic increases from upstream to downstream locations
Atrazine and glyphosate were detected at both upstream locations and at the downstream location.
✗ Incorrect
- This just states that pesticides were detected at all locations but doesn't address the intensification aspect
Malathion and 2,4-D showed relatively smaller increases from upstream to downstream locations.
✗ Incorrect
- Focuses on pesticides that showed smaller increases, contradicting the idea of significant intensification
Atrazine and glyphosate showed the most dramatic concentration increases from upstream to downstream.
✓ Correct
- Identifies Atrazine and Glyphosate as showing most dramatic increases
- Atrazine increased roughly 4-7 times, Glyphosate increased roughly 3-4 times
- These are the largest concentration jumps, supporting the significantly intensifying conclusion
Chlorpyrifos showed the highest absolute concentration at the downstream location.
✗ Incorrect
- Focuses on absolute concentration rather than the increase, missing the intensification aspect