This is a set of reference books for the 2023 correspondence course on pollution control management (water quality). They have been read quite a bit and show some wear. The materials are for a correspondence course, but the correspondence course itself is not available. There may be some scratches and bending on the reference books. These are used items, so please refrain from purchasing if you are sensitive to condition. Thank you. I passed the Pollution Control Water Quality Type 2 certification exam! Price: ¥40,920 (Japan Environmental Management Association for Industry)