Effects of a Clay Cap on Contaminants

As a result of agricultural, commercial and industrial activities conducted in the absence of environmental regulations and enforcement in the past, sediments contaminated by organic compounds, heavy metals, and other potentially toxic chemicals have accumulated in many of the world’s deepwater and wetland environments. These sediment-borne contaminants can eventually become incorporated into aquatic food webs and adversely affect ecological receptors like benthic organisms and fish, and ultimately pose a risk to human health. This project investigated a new in situ capping technology that could be used to remediate and/or manage contaminated sediments. AquaBlok (AB) is a patented, composite-aggregate technology comprised of a solid core, an outer layer of clay material, and polymers. When placed in water and over sediment, AB hydrates forming a layer between contaminants in sediment and the overlying water. Other materials – such as organic matter or plant seeds – can be incorporated into the AB as needed. Kearny Marsh in the NJ Meadowlands was chosen as the site for the field study because it has been chronically contaminated by landfills, leaching and run-off. The study design involved five treatments done in duplicate. The treatments were as follows: