Water pollution! What is it, where does it originate, how is it detected, how does it affect our environment, what can you do? This chart is packed full of informative text to support colorful drawings and provide answers to common questions about water pollution. Large center map details 47 water pollutants and methods for managing them. Table lists physical and chemical data. Detailed diagrams show the aquatic food chain, the nitrogen and mercury cycles, and a map shows the prevalence of water pollution in the United States. Printed on durable, heavyweight paper. Size: 28" x 221/2".