Effects of chromated copper arsenate (CCA) wood preservative on early fouling community formation

The effects of the anti-marine-borer timber preservative CCA (a pressure im pregnated solution of copper, chromium and arsenic compounds) on early foul ing community formation were investigated during a number of field trials. The formation of a biofilm on the surface of CCA-treated and untreated timb er panels of Scots pine was examined by scanning electron microscopy follow ing submersion in Langstone Harbour, Portsmouth, UK for periods of 2, 7, 14 and 28 days. Results indicated a slightly faster rate of biofilm formation after 2 and 7 days of exposure on untreated timber compared to CCA-treated timber, although no differences were visible between panels after 14 and 2 8 days exposure, or between panels treated to different CCA loadings after all exposure periods. Settlement of the serpulid Ficopomatus enigmaticus an d two species of barnacles (Elminius modestus and Balanus crenatus) onto th e surface of untreated and CCA-treated panels of Scots pine was examined fo llowing 4 weeks exposure in a brackish water millpond at Emsworth, West Sus sex. Numbers of individuals were higher on CCA-treated panels than on untre ated panels, and in the case of F. enigmaticus abundance of individuals inc reased with increasing preservative loadings. Early colonization by macroal gal species on the surface of CCA-treated and untreated panels of Scots pin e was examined following submersion of panels in Langstone Harbour for a pe riod of 4 weeks. Percentage cover of most species of algae was similar on t he surface of CCA-treated and untreated panels, with the exception of Hinck sia granulosa and Ceramium nodulosum which had significantly higher percent age cover on untreated panels. Possible explanations for the recruitment pa tterns are discussed. (C) 2001 Elsevier Science Ltd. All rights reserved.