The majority of wood products are treated with water-borne preservatives, the most common being chromated copper arsenate (CCA), ammoniacal copper quat (ACQ), and ammoniacal copper zinc arsenate (ACZA).

Pressure treated timber is timber impregnated with chromated copper arsenate under pressure and vacuum cycles. These preserve the timber from various fungicides that would normally eat the timber reducing its life-span.

Copper arsenate is frequently used for the treatment of wood against insects, fungs, bacteria.

I don't know if this is the best, but a typical product and process would be the application of CCA (Chromated Copper Arsenate) to the wood under relatively low pressure. That process is commonly referred to as 'pressure treating' and leads to long term protection against a salt-water environment. Wolmanized wood refers to a specific brand of pressure treated wood.

An agardite is any of a group of copper arsenate minerals which contain varying proportions of rare earth elements such as cerium, neodymium, lanthanum and yttrium.