Cooking with contaminated marijuana?

well i read something about cooking with marijuana (weed, pot, blahblah whatever) can be bad if it gets contaminated....er uh sprayed with pesticide from whatever the hell place you're getting it from....so i guess smoking pesticides is better than eating them? lolz iono , my question revolves around like if you should do it anyway, risk it and cook it, if getting it from an anonymous dealer and not...iono a garden you own yourself in Amsterdam. It's pretty bad on your lungs to smoke, but risking eating something bad is ...bad as well :P. Its also kinda a question of where this stuff is trailing down from, like in Canada...where would some high school guy(who else would I buy it from?) who's going to sell it be getting it from? Like I would think in the area I’m in I’m getting it from some locally grown place, but you never know.. Answer your questions, yeah im in high school, yes i have smoked a couple times, didnt have a problem with smoking ...but yeah it is still disgusting smoking. Anyway , thanks for any answers :)