ICAR AICE-JRF/SRF Pesticides in the Environment: Fate, Risk & Reduction: practice questions

1 · Classification of pesticides by target, chemistry and toxicity · medium

Imidacloprid, thiamethoxam and clothianidin belong to which group?

1. Synthetic pyrethroids
2. Neonicotinoids
3. Organochlorines
4. Diamides

2 · Environmental fate: sorption, degradation, volatilisation, leaching, runoff · hard

A pesticide with Koc = 300 L/kg is applied to a soil with 2% organic carbon. Its Kd in this soil is:

1. 150 L/kg
2. 600 L/kg
3. 0.067 L/kg
4. 6 L/kg

3 · Environmental fate: sorption, degradation, volatilisation, leaching, runoff · hard

Strongly sorbed pesticides such as paraquat reach surface water mainly:

1. Dissolved in leachate below the root zone
2. As vapour from the leaf surface
3. Through uptake and release by crop roots
4. Attached to eroded soil particles

4 · Persistence and half-life · hard

A crop residue of 2 mg/kg has DT50 10 days. After 30 days, assuming first-order decline, the residue is:

1. 0.67 mg/kg
2. 0.25 mg/kg
3. 0.5 mg/kg
4. 0 mg/kg

5 · Persistence and half-life · hard

A pesticide has a first-order rate constant of 0.0347 per day. Its half-life is:

1. 0.024 days
2. 20 days
3. 2 days
4. 28.8 days

6 · Effects on non-target organisms: pollinators, aquatic life, soil biota · medium

Aquatic acute toxicity tests on Daphnia usually report:

1. A 96-hour LD50 measured by oral dose
2. A 30-day NOAEL in rats
3. A soil half-life in days
4. A 48-hour EC50 for immobilisation

7 · Effects on non-target organisms: pollinators, aquatic life, soil biota · hard

Why are indirect food-web effects of herbicides on farmland birds hard to capture in standard regulatory tests?

1. Tests measure toxicity, not loss of food plants and insects
2. Herbicides are always directly toxic to birds at field rates
3. Birds never feed on insects in farmland
4. Herbicides do not affect any plant species

8 · Effects on non-target organisms: pollinators, aquatic life, soil biota · medium

Bees can be exposed to neonicotinoid seed treatments through:

1. Only direct spraying of the open flowers in the crop
2. Dust at sowing and residues in pollen and nectar
3. Only drinking rainwater far from fields
4. Feeding on the treated seed itself

9 · Persistent organic pollutants and the Stockholm Convention · medium

Which of the following was NOT one of the original 'dirty dozen' POPs?

1. Endosulfan
2. Aldrin
3. Heptachlor
4. Toxaphene

10 · Persistent organic pollutants and the Stockholm Convention · hard

Lindane and the other hexachlorocyclohexanes were added to the Stockholm Convention in:

1. 2009
2. 2001
3. 2004
4. 2019