toxic waste site vs trash dump

toxic waste site and trash dump both are nouns.

Word	Noun	Adjective	Verb	Adverb
toxic waste site	Yes	No	No	No
trash dump	Yes	No	No	No

As nouns, trash dump is a hypernym of toxic waste site; that is, trash dump is a word with a broader meaning than toxic waste site:

toxic waste site: a location where toxic wastes can be or have been disposed of (often illegally)
trash dump: a piece of land where waste materials are dumped

Other hypernyms of toxic waste site include dump, dumpsite, garbage dump, rubbish dump, waste-yard, wasteyard.

toxic waste site (noun)	trash dump (noun)
a location where toxic wastes can be or have been disposed of (often illegally)	a piece of land where waste materials are dumped