PARENT SESSION
MP8b Biomagnification through marine food chains
4:30 PM to 6:30 PM, Monday, 07 May 2001
Session Chair: P. Garrigues
Room 8

(142) Distribution of Phthalate Esters in a Marine Ecosystem.

Mackintosh, Cheryl¹, Jing, Hongwu¹, Chong, Audrey¹, Ikonomou, Michael², Gobas, Frank¹, ^{1 2}

ABSTRACT- Phthalate esters (PE's) are widely used chemicals, with over 4 million tonnes being produced worldwide each year. They have been observed in various environmental media and in several locations throughout North America and Europe. PE's exhibit a wide range of octanol-water partition coefficients (Kow) (i.e., ranging from 10^1.6 for dimethyl phthalate to 10^12.06 for ditridecyl phthalate), and therefore, some congeners have the potential to bioconcentrate and biomagnify in aquatic food-chains. However, due to the lack of field studies, reliable evidence regarding the actual bioaccumulation behavior of PE's in the field does not exist. To investigate the food-chain bioaccumulation potential of phthalate esters, we conducted a field study in British Columbia, Canada, which involved collecting samples of water, sediment and ten marine species, representative of both benthic and pelagic food chains. Samples were then analyzed by GC-MS for eight individual PE congeners (i.e., dimethyl, diethyl, di-isobutyl, di-n-butyl, benzyl-butyl, di(2-ethylhexyl), di-n-octyl, di-n-nonyl), and by LC-ESI/MS for five isomeric mixtures (i.e., C6, C7, C8, C9, C10). Environmental concentrations were then determined and the corresponding fugacities were calculated using the fugacity capacity of the medium (based on organic carbon content in sediments and lipid content in biota). The results reveal that PE fugacities in the sediment are greater than those in the water. Fugacities in the biota generally fall between the sediment and water fugacities, and decline slightly with increasing trophic level. These results suggest that PE's do not biomagnify in the food-chain. It is hypothesized that a first-pass biotransformation effect may be responsible for this lack of biomagnification. However, the observation that PE fugacities in the biota are similar to those in the water indicates that PE's do bioconcentrate.

Key words: phthalate esters, marine, bioaccumulation, fugacity