Sources of Pollution and Human Impacts on Ecosystems：练习题

In an agricultural watershed, the concentration of phosphorus in runoff is measured at \( 0.45 \text{ mg/L} \). If the total annual runoff volume from a \( 500\text{-hectare} \) farm is \( 1.2 \times 10^6 \text{ m}^3 \), calculate the total mass of phosphorus (in kg) entering the downstream lake annually.

An investigator measures the Biological Oxygen Demand (BOD) and Dissolved Oxygen (DO) levels along a river downstream from a point source of organic waste. Which of the following descriptions best characterizes the 'Septic Zone' of the resulting oxygen sag curve?

Which of the following best describes the process and environmental impact of 'Thermal Pollution' in aquatic systems near industrial facilities?

A municipal wastewater treatment plant utilizes a multi-stage process to treat sewage. During the Secondary Treatment stage, air is continuously bubbled through the wastewater in an aeration tank. Which of the following best describes the biological mechanism and the specific goal of this stage?

A specific wetland ecosystem is found to have a high concentration of methylmercury in its top predators. Which of the following conditions in the sediment most likely facilitates the conversion of inorganic mercury to the highly bioavailable methylmercury form?

A city monitors its wastewater discharge for Biochemical Oxygen Demand (BOD). If the BOD levels increase significantly downstream from a point source, describe the resulting changes in the dissolved oxygen (DO) sag curve and the survival of sensitive macroinvertebrates.

Unit 8: Aquatic and Terrestrial Pollution
An industrial site is found to be leaking methylmercury into a nearby lake ecosystem.
(a) Describe the process of biomagnification and explain why top predators like ospreys or large bass are more significantly affected than primary producers.
(b) Discuss the physiological effects of methylmercury on human health, specifically focusing on the nervous system.
(c) A scientist measures the concentration of methylmercury in the water as \( 0.00005 \text{ ppm} \) and in the tissues of a tertiary consumer as \( 25 \text{ ppm} \). Calculate the magnification factor.
(d) Propose a remediation strategy to reduce the impact of heavy metal pollution in the lake sediment and explain one limitation of this strategy. <\/p>