FISHERY BULLETIN: VOL. 81, NO. 3 



5 10 100 500 1000 5000 



Initial Ben zo(a|py rene Concentration (ppb) 



FIGURE 4. — Mean notochord length of California grunion embryos 

 (slashed bars) and yolk-sac larvae (black bars) after 14-d incubation 

 in seawater containing 0-5,000 ppb benzo(a)pyrene. Vertical lines 

 = SD; numbers in parentheses = total no. embryos or larvae. 



however, without continued addition of BaP; in fact, 

 it decreased to about 1 ppb after several hours. Ad- 

 ditional BaP dissolved in ethanol resulted in levels 

 that decreased to near zero in 24 h. Struhsaker 

 (1977) reported a similar difficulty in maintaining a 

 stable concentration of benzene in seawater and at- 

 tributed this to the volatility of benzene. 



Because the uptake of polycyclic aromatic hy- 

 drocarbons occurs primarily via the aqueous BaP 

 fraction, rather than by direct accumulation from sur- 

 rounding sediment (Roesijadi et al. 1978), the ex- 

 posure of grunion eggs to BaP in these experiments 

 may simulate what occurs in the natural environ- 

 ment. For example, an oil spill may result in initially 

 high concentrations of hydrocarbons, but photoox- 

 idation, adsorption into sediments and water-column 

 particulates, and tidal action will decrease the con- 

 centrations of various oil constituents (such as BaP) 

 over time. We have periodically monitored unfiltered 

 waters of the Los Angeles Harbor for BaP concentra- 

 tion during the period 1977-81. Levels of BaP fluc- 

 tuated from below the limit of detectability (<0.1 

 ppb) up to 5.4 ppb (Puffer et al. 1979). Niaussat and 

 Auger (1970) have reported levels of 1.6 ppb BaP in 

 seawater collected from a remote, isolated atoll in the 

 eastern tropical Pacific Ocean. BaP levels in sand 

 collected offshore of Cabrillo Beach in the Los 

 Angeles Harbor ranged from 223 to 471 ppb (Duncan 

 and Puffer 1982) and as high as 18,000 ppb in 

 sediments from the inner Los Angeles Harbor 



(Gossett et al. 1983). Concentrations of BaP in 

 sediments worldwide have ranged from nondetect- 

 able levels up to 15,000 ppb (Neff 1979). This sug- 

 gests that embryos may be exposed to high levels of 

 BaP in interstitial water during incubation in sand. 

 As there were no prior studies regarding the effect of 

 BaP on early grunion development, we utilized a wide 

 range of BaP concentrations to achieve various tissue 

 burdens. This not only reflects the broad range of ex- 

 posure in nature, but also affords an opportunity to 

 assess the sensitivity of eggs incubated under con- 

 trolled conditions in seawater containing various 

 concentrations of BaP and to correlate observed ef- 

 fects with known tissue BaP levels in embryos. 



The extent of BaP uptake by California grunion em- 

 bryos was directly proportional to initial and steady- 

 state BaP concentration in seawater. By day 15, em- 

 bryos accumulated BaP at levels 146-437 times the 

 steady- state BaP concentration in seawater. 



Comparative BaP bioaccumulation factors range 

 from 5,142 to 21,000 for rainbow trout alevins and 

 flatfish larvae, respectively (Hose et al. 1981; Han- 

 nah et al. 1982) and 861 for the clam Maeoma in- 

 quinata (Roesijadi et al. 1978). While Hannah et al. 

 (1982) noted an increase over time in BaP concen- 

 trations in embryonic rainbow trout, tissue BaP 

 levels in California grunion remained essentially con- 

 stant from day 3 to day 15. Eldridge et al. (1978) 

 demonstrated that tissue levels of benzene in Pacific 

 herring, Clupea harengus pallasii, reached equilib- 

 rium within 6-12 h at 11 times the initial water con- 

 centration. Steady-state tissue levels of BaP 

 probably represent an equilibrium between pollu- 

 tant absorption, embryonic metabolism, and excre- 

 tion of the more hydrophilic metabolites (Binder and 

 Stegeman 1980). 



The observed alterations in development of Califor- 

 nia grunion exposed to BaP include 1) hatching, 2) 

 abnormalities, and 3) reduction of notochord length. 

 The earliest consequence of egg exposure to BaP was 

 a reduction in hatching rate. Initial concentrations of 

 BaP >24 ppb caused a significant mortality of yolk- 

 sac larvae. These results are consistent with those 

 reported by Ernst et al. (1977) who showed a 25/25 

 (100%) hatching rate of Fundulus grandis eggs ex- 

 posed to 1.1 ppm water-soluble fraction of No. 2 fuel 

 oil, a 4/25 (16%) hatching rate when exposed to 2.2 

 ppm, and 0/25 (07c) when exposed to 4.4 ppm. BaP 

 has long been known to be embryo toxic in rodents 

 (Rigdon and Rennels 1964) and more recently in 

 sand sole, Psettichthys melanostictus, (Hose et al. 

 1982) and following maternal exposure in flathead 

 sole, Hippoglossoides elassodon, (Hose et al. 1981). 

 Furthermore, petroleum hydrocarbons, including 



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