Human Health, Exposure, and Personal Protective Equipment
Exposure routes and toxicity measures
Candidates must know the four exposure routes: dermal, inhalation, oral and ocular, with dermal being the most common in landscape work. Understand the difference between acute toxicity (single exposure, expressed through signal words and hazard statements) and chronic toxicity (long-term effects such as carcinogenicity or reproductive harm). Learn that LD50 and LC50 are measures of toxicity - a lower value means a more toxic substance - and that "-cide" products vary widely, so never generalise from one product to another.
Know how to read the label's PPE section and how to select, wear, inspect and remove PPE: chemical-resistant gloves appropriate to the product, coveralls, boots, eye protection and respiratory protection where specified. Traps: assuming a dust mask protects against vapours; assuming gloves are reusable indefinitely; and removing gloves before removing other contaminated clothing. Learn the decontamination sequence and the importance of washing before eating, drinking or smoking.
Symptoms, sensitisation and first aid
Understand that symptoms of overexposure (headache, dizziness, nausea, sweating, blurred vision, pinpoint pupils) can mimic heat illness or flu, so exposure must be considered when symptoms appear during or after work. Know that some products cause sensitisation, so a reaction can occur on a later, lower exposure. First aid follows the label: remove from exposure, remove contaminated clothing, wash skin, flush eyes for the specified time, and call the poison centre or emergency services. Never induce vomiting unless directed.
Rule of thumb: PPE level is set by the label and the task, not by the weather or convenience; if a task requires more PPE than you have, the task does not proceed.
Worked example: a worker feels dizzy and sweaty after mixing concentrate in a closed shed. Correct response: stop work, move to fresh air, remove contaminated clothing, wash, call for medical advice with the product label in hand, and report the incident - not "drink water and continue".