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Impact of chromated-cooper-arsenate (CCA) - treated wood on the marine environment
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Abstract(s)
Foram imersos em zonas costeiras (Sagres: Portugal; Portsmouth: U.K.) painéis de madeira tratada com crómio-cobre-arsénio (CCA) e de madeira controlo. Efectuaram-se colheitas de organismos (Mytílus spp.)
aderidos aos paineis, após 12 e 18 meses de imersão, para análise de metais (Cr e Cu) na parte edivel.
Compararam-se as concentrações de metais nos mexilhões, entre os diferentes locais e alturas de amostragem. Foi determinado o efeito da carga de CCA nas concentrações de metais.
Foram imersos em água-do-mar pequenos blocos de madeira tratada com CCA e de madeira controlo, sob condições laboratoriais. Monitorizaram-se as concentrações de metais (Cr e Cu) nas soluções de água-domar.
Deterrninou-se a taxa de libertação de metais e a sua relação com o tempo de imersão e com a carga de CCA. Estudou-se a sobrevivência de Artemia salina exposta às soluções de água-do-mar.
Os resultados demostraram que os níveis de crómio nos organismos de Portsmouth eram mais baixos do que nos de Sagres. Não se verificou uma relação signjficativa entre carga de CCA e os niveis de crómio.
Os níveis de cobre nos organismos de Sagres (12 meses) eram significativamente mais elevados do que nas restantes amostras; estes organismos também apresentavam um aumento das concentrações de cobre com o aumento da carga de CCA; esta relação não foi encontrada nas restantes amostras.
Não foi libertado crómio, ou foi-o em pequenas quantidades, dos blocos de madeira. Por outro lado, foram libertadas quantidades significativas de cobre dos blocos tratados. A taxa de libertação foi semelhante entre as diferentes cargas de CCA estudadas e diminuiu com o tempo de acordo com a relação: |1gCu/cmz/h = a t`b (a e b são constantes e b>0). Não ocorreram efeitos letais em A. salina resultantes da exposição às soluções de água-do-mar.
Os resultados observados foram discutidos em função de alguns factores biológicos e fisico-químicos.
Panels of chromated-copper-arsenate (CCA)-treated wood and control wood were immersed in coastal areas (Sagres: Portugal; Portsmouth: U.K.). Fouling organisms (Myfilus spp.) were collected after 12 and 18 months of wood immersion for metal (Cr and Cu) analysis in the soft tissues. Heavy metal levels in the mussels were compared between the different places and time of sampling. The effect of CCA loadings on metal concentrations was detennined. Small wood blocks of CCA-treated wood and control wood were immersed in sea-water, in laboratory conditions. Metal (Cr and Cu) concentrations in leachate solutions were monitorized. Metal release rate was determined and its relationship with leaching time and with CCA loading was investigated. Artemia salina survival exposed to leachate solutions was assessed. Chromium levels in the organisms from Portsmouth Were lower than in the ones from Sagres. There was not a significant relationship between CCA loading and chromium levels. Copper levels in the organisms from Sagres (12 months) were significantly higher than in the remaining samples; these organisms also presented higher copper concentrations with higher CCA loading; this relationship was absent in the remaining samples. Little or no chromium was released from the small blocks, while significant amounts of copper were released from the treated blocks. The release rate was similar between the different CCA loadings studied and decreased with time according to the relationship: |IgCu/cmg/h = a t"' (a and b are constants and b>0). There Were not lethal effects on A. salina from the exposure to leachate solutions. The observed results were discussed in relation to some biological and physicochemical factors.
Panels of chromated-copper-arsenate (CCA)-treated wood and control wood were immersed in coastal areas (Sagres: Portugal; Portsmouth: U.K.). Fouling organisms (Myfilus spp.) were collected after 12 and 18 months of wood immersion for metal (Cr and Cu) analysis in the soft tissues. Heavy metal levels in the mussels were compared between the different places and time of sampling. The effect of CCA loadings on metal concentrations was detennined. Small wood blocks of CCA-treated wood and control wood were immersed in sea-water, in laboratory conditions. Metal (Cr and Cu) concentrations in leachate solutions were monitorized. Metal release rate was determined and its relationship with leaching time and with CCA loading was investigated. Artemia salina survival exposed to leachate solutions was assessed. Chromium levels in the organisms from Portsmouth Were lower than in the ones from Sagres. There was not a significant relationship between CCA loading and chromium levels. Copper levels in the organisms from Sagres (12 months) were significantly higher than in the remaining samples; these organisms also presented higher copper concentrations with higher CCA loading; this relationship was absent in the remaining samples. Little or no chromium was released from the small blocks, while significant amounts of copper were released from the treated blocks. The release rate was similar between the different CCA loadings studied and decreased with time according to the relationship: |IgCu/cmg/h = a t"' (a and b are constants and b>0). There Were not lethal effects on A. salina from the exposure to leachate solutions. The observed results were discussed in relation to some biological and physicochemical factors.
Description
Keywords
Madeira CCA Poluição marinha Biomonitorização Deplecção Toxicidade.