<prompt> Translate the following text to EnglishUtafiti huo unasema kuwa kemikali hizo zinapatikana kwenye mimea ya mashamba ya kilimo na zinatokana na dawa za kuua wadudu, kama vile zile zilizotokea kwa wafanyakazi wa kutengeneza saladi.  <response>: The exposure comes from chemical residue on plants in farm fields and from pesticide drift, such as the incidents lettuce workers described, according to the survey. 