ACUTE TOXICITY AND TOXICOKINETICS OF 4-HEPTYLPHENOL IN JUVENILE ATLANTIC COD (GADUS-MORHUA L.)

Heptylphenol has been detected in produced water from various oil prod uction platforms in the Norwegian sector of the North Sea and may be o f environmental concern due to hydrophobic properties and slow biodegr adation in the marine environment. The n-octanol/water partition coeff icient of 4-heptylphenol (4-HP) was estimated by a high-performance li quid chromatographic correlation analysis. Acute toxicity and toxicoki netics of 4-HP in juvenile Atlantic cod (Gadus morhua L.) were investi gated in flow-through exposure systems using unlabeled and C-14-labele d 4-HP, respectively. The results show that 4-HP was moderately hydrop hobic (log K-ow = 4.5) and toxic to juvenile cod (96 h LC50 = 2.9 mu m ol/L). The toxicokinetics of 4-HP was calculated using a one-compartme nt first-order kinetic (1CFOR) model (k(1) = 29.94 +/- 1.83, k(2) = 0. 052 +/- 0.011/h, t(95) approximate to 58 h and t(1/2) approximate to 1 3 h). The values obtained corresponded to a steady-state and kinetic b ioconcentration factor (BCF) of 555 and 578, respectively. The distrib ution pattern of 4-HP (and/or metabolites) at steady state and after 9 6 h of recovery in uncontaminated seawater was dominated by the gastro intestinal system possibly owing to biotransformation and elimination through these organs. The results also revealed that neither 4-HP nor possible metabolites bind to macromolecules or tissue structures in th e fish.