Over 2000 captive seawater sites in the US exhibit copper levels that are toxic to algae, mollusks and other crustaceans, and certain sea grasses. The toxic presence is the result  of  copper  leaching from  copper-based paints on ocean going vessels. In fact, toxic copper levels are at a crisis  level in bays, harbors,  and marinas where industrial boats and pleasure yachts anchor.

Toxic copper enters the water column at high parts per billion  levels.  The US EPA  and  numerous  state  and local water quality boards have mandated limits, known as Threshold Maximum Daily  Loads  (TMDL’s), to numerous  bays and harbors  requiring  the reduction  of toxic copper levels  in seawater by specified dates. Responses often focus on either treating the boats, moving the  water,  and/or  by treating  the water.  Treating boats has had a limited effect on overall copper reduction as documented  in controlled  studies, and moving the water out to the ocean has also had limited success, since most bays and harbors, whether natural or man-made, have limited water flow.

Factors  effecting the ambient toxic  copper  levels  in bays and harbors  include  the current  load of soluble toxic copper and the addition of new total copper loads from boat hulls. Additionally, total copper binds to organic matter in the seawater, eventually chelating upon decomposition and settling in the silt layer. Over time, chelated copper can re-solubilize to the toxic form  of copper especially if water levels of soluble toxic copper are depleted.

In response, Red Lion Chem Tech in San Diego pioneered two remedial approaches that work. One employs submersible ballasts to address the soluble toxic copper problem in situ, and the other, involving ‘pump and treat,’ was developed for reduction in new total copper load. Through these advances in proprietary coordination chemistry, Red Lion Chem Tech has demonstrated the removal of >98% copper from seawater. Submersible ballast systems containing proprietary adsorbent materials remove soluble toxic copper via wave action, and ‘pump and treat’ methods remove total copper, including soluble copper, copper absorbed on organic matter, and chelated copper remaining in the water column. After successful lab testing, field trials are now under way in San Diego bay.

Reprinted with permission. From the Nov/Dec 2015 issue of ECO (Environmental Coastal & Offshore) magazine.