Marine birds are exposed to several types of 

 environmental pollutants: petroleum hydro- 

 carbons, organochlorines, heavy metals, and 

 others. Because few data are available for 

 northern North America, potential problems 

 for marine birds there must be judged from 

 observations in other geographical areas. 



Certain marine birds may serve as indi- 

 cators of environmental pollution on a global 

 scale because (1) they usually can be identified 

 even in an advanced state of decomposition, 

 after a long period of submergence in sea- 

 water, or when thickly covered with oil; (2) 

 they are geographically widespread, often are 

 very numerous, and feed on a wide range of 

 marine organisms; and (3) most species nest 

 colonially and lay large, distinctively marked 

 eggs that are often easily collected and consti- 

 tute distinct units for comparison between 

 species (Vermeer and Reynolds 1970; Prestt 

 1971). 



Eggs serve as particularly useful sample 

 units for analysis of organochlorines and 

 certain heavy metals, particularly mercury, 

 because they do not decompose rapidly and 

 are easily handled. Some marine bird species 

 lay additional clutches if the first is removed; 

 therefore, eggs may be taken without severe 

 adverse effects on populations. This charac- 

 teristic is of particular importance because 

 studies are sometimes not begun until it is ap- 

 parent that a population is declining (Prestt 

 1971). 



Organochlorine concentrations in the egg 

 are about equal to whole body concentrations 

 found in the female at the time the egg was 

 laid (Keith and Gruchy 1972). Although some 

 microbes have the ability to metabolize or- 

 ganochlorine pesticides under certain condi- 

 tions (Matsumura 1974), putrefaction does 

 not significantly affect residue analysis for 

 DDT and its metabolites (Mulhern and 

 Reichel 1970). During incubation, however, 

 the developing embryo appears to metabolize 

 DDT to ODD and DDE (Abou-Donia and 

 Menzel 1968; Blus et al. 1974b). Chemical resi- 

 due concentrations can be adjusted for the 

 loss of moisture and lipids that occurs during 

 incubation (L. F. Stickel et al. 1973). 



Eggs may not be the best tissue for mea- 

 surement of all metals, because certain heavy 

 metals apparently are not readily transferred 

 to them (Anderlini et al. 1972). This, however, 

 is not true of mercury. Under certain circum- 



stances, feathers may be the best tissue to 

 analyze for mercury residues (Stickel 1971). 

 However, unlike liver and muscle tissue, mer- 

 cury residues in feathers tend to reflect body 

 burdens at the time the feathers were grow- 

 ing. The liver, which is a major organ of me- 

 tabolism, or muscle appear to be the best tis- 

 sues for measuring current exposure to mer- 

 cury (Backstrom 1969; Vermeer and Arm- 

 strong 1972b; Fimreite 1974). Other heavy 

 metals may be concentrated in other tissues. 

 For example, residues in the bones, kidneys, 

 and brain, as well as in the liver, appear to be 

 the best measure of exposure to lead (Long- 

 core et al. 1974b). The transfer of petroleum 

 hydrocarbons to eggs has not been reported, 

 but may be expected to occur. 



Unless otherwise indicated, all chemical 

 residues in the present report are expressed 

 on a wet-weight basis. 



Petroleum Hydrocarbons 



Because much of the current information 

 concerning the significance of oil pollution in 

 the estuarine and marine environment has 

 been included in recent reviews (National 

 Academy of Sciences 1973, 1975a; Moore and 

 Dwyer 1974; Evans and Rice 1974; Vermeer 

 and Vermeer 1974a, 1974b; Farrington 1977), 

 we have avoided an extensive review here. 

 However, some of the general information, 

 taken in part from these reviews, is pertinent 

 to our subject and has been included along 

 with that more specifically related to birds. 



Crude oil and petroleum products are com- 

 plex mixtures of chemicals with individual 

 compounds numbering in the tens of thou- 

 sands with wide molecular weight ranges 

 (Farrington 1977). No one method of analysis 

 is available that will provide reliable esti- 

 mates of the concentration of the entire range 

 of petroleum compounds, and there has yet to 

 be a complete analysis of a single crude oil. 

 Therefore, reports of the presence or absence 

 of petroleum pollution should be carefully 

 evaluated to be certain that the methods of 

 chemical analysis employed would indeed pro- 

 vide the information reported. 



Vanadium and nickel are present in appre- 

 ciable quantities (> 100 ppm) as organometal- 

 lics indigenous to crude oil, and other trace 

 metals are picked up during production or 

 transportation of crude oil (Whisman and 



