id	keyword
fens-818	effect
fens-818	water
fens-818	quality
fens-818	pollution
fens-818	index
fens-818	water quality
fens-818	zeremna
fens-818	surface
fens-818	food
fens-818	stations
fens-818	skikda
fens-818	environment
fens-818	river