Final answer:
The major categories of pesticide exposure are chronic and acute exposure (categorized over time), and oral, dermal, inhalation, and ocular exposure (categorized by route of entry). Acute exposure involves short-term, high-level contact, while chronic exposure is long-term and low-level. The answer to the student's question is d. a and b as it includes both time and route-based categories.
Step-by-step explanation:
Major Categories of Pesticide Exposure
The major categories of pesticide exposure include acute and chronic exposure, as well as different routes through which pesticides can enter the body. Acute poisoning generally refers to short-term, very high-level exposure, which is a significant issue in countries like Sri Lanka. In contrast, chronic poisoning involves long-term, low-level exposure, which is a more pervasive problem in developed countries such as Canada. These chronic exposures often come from contact with pesticide residues present in food, air, water, and other environmental sources.
Moreover, there are three main routes of exposure to chemicals, and hence pesticides:
Oral exposure through ingestion of substances,
Dermal exposure via skin contact,
Inhalation exposure through breathing in vapors or dust.
Occupational hazards also play a significant part in pesticide exposure. Agricultural workers, manufacturing employees, retail store staff, and emergency responders like firefighters and police officers are among those most at risk of both acute and chronic pesticide illnesses. Their work may involve handling pesticides, operating equipment like rotary fan mist sprayers, or responding to emergencies where pesticides are present without prior knowledge of the risk.
Therefore, the correct answer to the student's question about the major categories of pesticide exposure is d. a and b, where 'a' represents chronic and acute, and 'b' points to oral and dermal exposure routes. Additionally, inhalation and ocular routes are also relevant regarding the ways pesticides can enter the body, rounding up the major exposure categories.