Common object around my house that could be used to model a cell

Depends on the type of cell. If it's a phone cell, then maybe a remote. If it's a prison or jail cell, the maybe a metal rod from the lights. If its a human cell, then maybe a round pill or a red cough drop.

Explanation:

poor water quality affects most estuarine organisms, including commercially important fish and shellfish. the pollutants that have the greatest impact on the health of estuaries include toxic substances like chemicals and heavy metals, nutrient pollution (or eutrophication), and pathogens such as bacteria or viruses.