noun
Refers to thick, muddy, often toxic sediment or waste, especially industrial or environmental sludge.
工場から出たヘドロが川に流れ込んだ。
Sludge from the factory flowed into the river.
ヘドロの処理には特別な設備が必要だ。
Special equipment is needed to treat the sludge.
Loanword from English 'sludge', adapted into Japanese as ヘドロ. The exact phonetic shift from 'sludge' to ヘドロ is uncertain, but it likely entered via early industrial or environmental terminology.