animal
bad
channel
chemical
contaminate
danger
dangerous
dark
dead
deadly
death
decay
dirty
disposal
ecology
ecosystem
environment
factory
fish
fishing
float
food
fresh
freshwater
garbage
grass
green
harmful
industry
lake
life
natural
nature
plague
poison
poisoning
polluted
pollution
pond
problem
river
rotten
rustic
sewage
smell
stink
toxic
waste
wastewater
water