Which statement best describes diquat's environmental fate?

• A. It rapidly degrades in water and disappears.
• B. It binds to soil and organic matter and accumulates in sediment, leaving biological activity low.
• C. It remains in the water column indefinitely.
• D. It volatilizes into the atmosphere.

Answer: (B)

Diquat tends to bind strongly to soils and organic matter because of its positively charged, bipyridyl structure. This sorption causes it to accumulate in sediments rather than stay dissolved in the water, which in turn reduces its availability to aquatic life in the water column and lowers observed biological activity there. It is not volatile, so it won’t readily move to the atmosphere, and it does not vanish from the aquatic environment instantaneously, though some degradation can occur. The key outcome is sediment-associated binding and persistence, which matches the statement about soil binding and sediment accumulation with lower biological activity in the water.