Sources, Distribution, Environmental Fate, and Ecological Effects of Nanomaterials in Wastewater Streams

Abstract

Engineered nanomaterials (ENM) are manufactured, as opposed to being an incidental by-product of combustion or a natural process, and they often have unique or novel properties that emerge from their small size. These materials are being used in an expanding array of consumer products and, like all technological developments, have both benefits and risks. As the use of ENM in consumer products becomes more common, the amount of these nanomaterials entering wastewater stream increases. Estimates of nanomaterials production are in the range of 500 and 50,000 tons per year for silver and titanium dioxide (TiO₂) alone, respectively. Nanomaterials enter the wastewater stream during the production, usage, and disposal of nanomaterial-containing products. The predicted values of nanomaterials range from 0.003 (fullerenes) to 21 ng L⁻¹ (nano-TiO₂) for surface waters, and from 4 ng L⁻¹ (fullerenes) to 4 μg L⁻¹ (nano-TiO₂) for sewage treatment effluents. Therefore, investigating the fate of nanomaterials in wastewater streams is critical for risk assessment and pollution control. The authors aim first to identify the sources of nanomaterials reaching wastewater streams, then determine their occurrence and distribution, and finally discuss their fate in relation to human and ecological health, and environmental impact.

KEY WORDS:

• nanomaterials
• wastewater
• ecotoxicity
• environmental fate
• aquatic system
• management