Journal of the Marine Biological Association of India

Volume 29 Issue 1&2

Investigations on the durability of pressure-treated timber against marine borer attack in Mandovi Estuary, Goa.

L. N. Santhakumaran, R. V. Krishnan and V. Kuppusamy

Performance of 8 timber species against biodeterioration, when pressure-treated with 3 preservatives (namely Copper-Chrome-Arsenic (CCA), Copper-Chrome-Boric (CCB) and Creosote : Fuel oil mixture (CFO) and exposed in Mandovi Estuary (Goa) for about 48 months, has been discussed. The untreated control panels were all badly damaged in less than 6 months and those treated with CCA (except panels of Anogeissus latifolia and Pterocarpus marsupium) and CFO were heavily attacked within 13 months. CCA-treated panels of P. latifolia, at absorptions of 16 kg and 32 kg per m3, failed within 35 months. Panels of P. marsupium with 16 kg per m' of CCA were severely destroyed in 18 mouths, whereas with 32 kg per m3 dosage they remained in excellent condition even after 48 months. CCB-treated panels Mangifera indica suffered only negligible damage in 25 months, but underwent 12 to 45 % destruction in 35 months.

Although six borer species were encountered on the panels, the extremely heavy incidence of Martesia striata was singularly responsible for the premature failure of even the treated panels. The rapidity of destruction exposes the high degree of borer hazard in Goa waters, necessitating still higher absorption of the preservatives.

Date : 31-12-1987