underwater
environmental
autumn
autumn leaf
background
biochemical
biochemically
branch
careless
chemical
chemistry
color
contamination
danger
dirty
dirty water
disaster
ecology
environment
fall
fall season
floating
foliage
fuel
garbage
green
hazard
hazardous
industrial
industry
lake
leaf
liquid
mine
nature
poison
poisonous
pollution
protection
river
toxic
toxic water
water