Dear Umbra, Recently, I've started to try to avoid plastics (especially plastic water bottles). For Christmas, my brother gave me a Camelbak-type water bottle. How safe is this? I assume it's as bad as most plastic water bottles. Timothy Kearney Issaquah, Wash. Dearest Timothy, Gifting quandary alert. But does it suck? Photo: iStockphoto Not all plastic water bottles are equal. In a larger context of avoiding plastic, we may occasionally find ourselves with a plastic bottle that is handy and use it for a while. There are certain exceptions: We should try to completely avoid polyvinyl chloride, PVC, which is …