Waste is related to Pollution. you are likely to find Pollution in/at/on Ocean. Ocean can be used for Fish. 
you are likely to find Nurse in/at/on Hospital. Hospital is a type of Facility. Facility is related to Prison. Prison is the opposite of Free. 
Waste <--RelatedTo--> Pollution --AtLocation--> Ocean --UsedFor--> Fish 
Nurse --AtLocation--> Hospital --IsA--> Facility <--RelatedTo--> Prison <--Antonym--> Free 