Summarize the following 20 words into 1 sentence.
toxic – substance – human – fish – water – environment – animals – pollution – health – threats
Toxic substances in water are a threat to the health of humans, fish, animals and the environment, causing pollution.
Complete the following task based on the instruction and optional input provided.### Instruction:
Summarize the following 20 words into 1 sentence.

### Input:
toxic – substance – human – fish – water – environment – animals – pollution – health – threats

### Output:
Toxic substances in water are a threat to the health of humans, fish, animals and the environment, causing pollution.