Is it safe to use pressure treated lumber for animal enclosures such as a bird feeder or fish pond retaining wall? I have heard that leaching may be a problem.
Outdoor enclosures for animals are an appropriate use for pressure treated lumber when you keep in mind a few factors. For ponds you will need to make sure that you choose a lumber a that is treated to the proper retention. The lumber end tag should note the end use as “Ground Contact/Freshwater Use.” A small amount of leaching takes place, and copper that is used in many pressure treated lumber does have aquatic toxicity. Generally the levels of leaching will only be problematic in situations where there is a large amount of treated wood compared to the volume of water and where there is a low water flow. For more information, the USDA Forest Product Lab discusses treated wood and environmental impact.
