The phrase "an important environmental problem" is correct and usable in written English.
It can be used when discussing issues related to the environment that have significant implications or consequences.
Example: "Climate change is an important environmental problem that affects ecosystems worldwide."
Alternatives: "a significant environmental issue" or "a critical environmental challenge".
Water contamination by organic compounds is an important environmental problem.
Heavy-metal pollution represents an important environmental problem due to the toxic effects of metals, and their accumulation throughout the food chain leads to serious ecological and health problems.
Air pollution, especially the reduction of the air pollution to some acceptable levels, is an important environmental problem, which will become even more important in the next 10 20 years.
The air pollution caused by automobiles and motorcycles is an important environmental problem to be solved.
Heavy metal pollution is an important environmental problem in the world because, unlike organic materials, heavy metals cannot be transformed by microorganisms and, therefore, accumulates in water, soil, bottom sediments and living organisms (Miretzky et al. 2004).
Cheese whey represents an important environmental problem because of its high organic matter content, with a BOD (Biochemical Oxygen Demand) = 30000 50000 ppm and a COD (Chemical Oxygen Demand) = 60000 80000 ppm (Siso 1996).
Oxygen depletion (temporal or permanent) in freshwater ecosystems is a widespread and globally important environmental problem.
The third important environmental problem in Kullu Valley, Himachal Pradesh, India was forest fire, a matter of concern to the people and the local administration.
Only five percent of those surveyed rated climate change as the most important environmental problem, yet more than two-thirds believed the phenomenon would cause substantial harm.
Yes, the president has a lot on his plate, and yes, climate change is by far the most important environmental problem, and arguably the most important problem, period, that the nation faces right now.
