Which type of entry route can cause immediate effects from pesticide exposure?

The ocular entry route can cause immediate effects from pesticide exposure because the eyes are highly sensitive and absorb chemicals rapidly. When pesticides come into contact with the eyes, they can produce immediate irritation, pain, or even damage to the ocular tissues. This route allows for a quick reaction due to the rich blood supply in the eye, which can lead to swift systemic absorption of harmful substances.

In contrast, while oral, dermal, and respiratory routes of exposure can also lead to significant health effects, they often do not manifest as quickly as ocular exposure. Oral exposure can take time for symptoms to develop as the pesticide must be digested and absorbed through the gastrointestinal tract. Dermal exposure may also take longer for effects to be felt, as the skin acts as a barrier, and absorption rates can vary. Respiratory exposure can lead to rapid effects as well, particularly with inhalation of vapors or aerosols, but typically not as immediate as the ocular route, which directly affects the sensitive tissues of the eye.