What does bioaccumulation refer to?

Bioaccumulation refers specifically to the accumulation of toxic substances in an organism over time. This process occurs when an organism absorbs pollutants or toxins faster than it can eliminate them. As a result, these harmful substances build up in the tissues of the organism, often leading to higher concentrations within its body compared to the surrounding environment.

This phenomenon is particularly concerning for certain chemicals, such as heavy metals and persistent organic pollutants, which can become more concentrated as they move through the food chain. Organisms at higher trophic levels often exhibit even greater levels of these toxins due to bioaccumulation, leading to serious health effects for them and potential risks to humans who consume them.

The other options do not accurately define bioaccumulation. While the accumulation of nutrients is a separate process, cellular growth and division are fundamental biological processes unrelated to the concept of accumulating harmful substances. Furthermore, the increase of biodiversity in an ecosystem relates to the variety of life and does not involve the accumulation of toxins within individual organisms.