Okay, the user wants me to translate "synthetic chemicals" into Japanese. Let me check the rules again. The first rule says to translate all content into Japanese. The second rule states that if the content is already in Japanese, leave it as is. The third rule is to provide only the translation without any explanations.
So, "synthetic chemicals" in Japanese would be "合成化学物質" (gousei kagaku busshitsu). I need to make sure there's no explanation, just the translation. The user also mentioned that for each message, I should respond with just the translation. Let me confirm the term again. "Synthetic" is "合成" and "chemicals" is "化学物質", so combining them gives "合成化学物質". That's correct. No need for any additional text. Just output the Japanese term.