Vol.1 part 4-5 - Department of Invertebrate Zoology

III . RESULTS
A. Sediments
Mean trace metal concentrations in surficial sediments
from all sampling stations are compared with
similar data from other investigations in the Gulf of
Mexico in Table 4 . Distribution of the trace metal
concentrations by platform and station is given in Appendix
B .
Computer generated scatter plots of surficial sediment
trace metal concentrations versus Fe concentrations
are given in Appendix C1 . The surficial sediment
trace metal concentrations normalized to the Fe concentration
are listed by platform and station in Appendix
C2 . All trace metal concentrations normalized to percent
clay are listed in tabular form by platform and station
in Appendix D1 . Normalization of surficial sediment
trace metal concentrations with the total hydrocarbon
content (%) (Nulton et al ., 1980) are presented in
Appendix E by platform and station .
Tabular and graphical presentations of the downcore
sediment trace metal data are presented in Appendices
F1 and F2, respectively . Downcore sediment Pb-
210 data are tabulated in Appendix G .
B. Biota
Table 5 lists the types of biota samples collected and
also the number of pooled and individual samples available
for analysis . Table 6 lists species of biota common
to other environmental investigations in the Gulf of
Mexico .
Table 7 is a comparison of the mean trace metal concentrations
in organs of Archosargus pro6atocephalus
(sheepshead) with similar data (muscle tissue) from the
BGOF (Tillery, 1980a) . A comparison of the mean trace
metal concentrations in organs of Chaetodipterus faber
(spadefish) with similar data from the BGOF (Tillery,
1980a) is presented in Table 8 .
Table 9 is a comparison of the mean trace metal burdens
in organs of Micropogon undulatus (Atlantic
croaker) with similar data from the Strategic Petroleum
Reserve (SPR) program baseline studies (Shokes, 1978)
and the STOCS environmental survey (Horowitz and
Presley, 1977) .
Mean trace metal concentrations in tissues of Lutjanus
campechanus (red snapper) are compared to similar
data from the S'TOCS study (Presley and Booth, 1979)
in Table 10 .
Table 11 is a comparison of the mean trace metal
concentrations in muscle tissue of Penaeus aztecus
(brown shrimp) with data from the SPR baseline survey
(Tillery, 19806), the STOCS study (Horowitz and Presley,
1977), and the MAFLA baseline survey (Johnson,
1979) .
Table 12 is a comparison of the mean trace metal
concentrations in muscle tissue of Penaeus setiferus
(white shrimp) with similar data from the SPR studies
(Shokes, 1978 ; Tillery, 19806), the STOCS study (Presley
and Booth, 1979), and the MAFLA study (could
and Morbert, 1979) .
TABLE 4 .
Comparison of the mean trace metal concentrations (ug/g dry wt) in surficial sediments
with other Gulf of Mexico studies
Ba Cd Cr Cu Fe' Ni Pb Zn V
Central mean z 77 0.30 8.9 11- 0.69 10 .2 18 .8 44 9.8
Gulf2 CV (070) 175 64 39 49 34 27 96 60 54
Platform Range 0-1515 0 .01-0 .92 2 .3-19 1 .0-45 0 .15-2 .0 3 .9-17 .2 0-136 14-193 0-44
Study n=147
Northwest Gulf3 mean z NA ° 0 .3 NA 11 .4 2 .18 22 .6 16 .5 73 .8 NA
of Mexico Range 0.02-0.7 2.0.24.8 0.53-3.34 5 .1-38.8 4.9-34.4 17 .6-132 .3
(Trefry &
Presley . 1976a)
SPR-Weeks2 mean x 37 0 .05 5 .09 2 .0 0.45 6 .2 5 .7 22 NA
Island, Summer CV (016) 45 37 17 40 10 8 22 8
1978 (Tillery, n=9
19806)
1 . concentration in wt %
2. SN HNO3 leach at room temperature
3 . 16N HNO3 + SN HCI leach with heat
4 . NA - metal not determined
I1