Is Sodium Bentonite Toxic to Fish?

Origin and Source

• In the Cretaceous period 70 millions of years ago, extensive volcanic activity resulting from tectonic convergence of the Pacific and North American plates spewed immeasurable amounts of volcanic ash into the atmosphere. Eventually, the ash was forced deep under the North American shifting plate drift, chemically altered from salt water eroded slits and sediments composing the silicate mineral deposits.

How it Works

• The active ingredient, montmorillonite, contains three layers of tetrahedron and octahedron sheets, held together by electrostatically isomorphic interlayer cations. The activity of water seeping between the silicate layers of monomolecular lattice becomes exposed to low electrostatic polar attraction that triggers intercrystalline swelling of several layers of water dipoles that form "stacked" tetrahedral structures causing the 2-micron-sized pellets to "swell 16 times their size and absorb 10 times its weight" when hydrated.

Mining and Production

• Open pit mining of sodium bentonite deposits can stretch for miles and as deep as 50 feet depending on epoch sea flows that formed the concentrated deposits to manufacture two types of commercially packaged properties. These are either a fine powder or granulation and purity can vary depending on the regional deposit and climatic influences.

Application for Ponds

• There are three methods for application in leaking ponds: Blanket Method, the most effective because of layering for new pond construction; Mixed Blanket Method, in which sodium bentonite is plowed in with the soil for new or drained ponds; and Sprinkle Method, which is used when the pond cannot be drained.

Sprinkle Method is Toxic for Fish

• The Sprinkle Method, used if the pond can't be drained or targeting isolated seepage areas, can pose a danger to fish if not applied correctly. To avoid harming fish, apply a granular grade of sodium bentonite (Granular Seal). The particles are large enough to sink to the bottom of the pond, gravitating toward the porous areas. Finer particle sodium bentonite will cloud the water, exposing fish to the tiny micro-particles of bentonite that will clog their gills and cause them to suffocate. To avoid harming the fish with the Sprinkle Method, apply in prescribed amounts and not during hot weather or in shallow water ponds. Application should be over several days. The Environmental Protection Agency approved sodium bentonite safe for aquatic life, but manufacturers warn excessive treatment or continuous water agitating during treatment causes poisonous clouding for aquatic life.