Heavy metals in sea turtles

Marine Pollution Bulletin TABLE 1

Medium annual mercury and copper concentrations in water and Enteromorpha sp. tissue with confidence intervals of the mean at p = 0.1 level of significance. Locations

Total Hg in water (tag 1-1) Dissolved Cu in water (tag 1- lI Particulate Cu in water (tag 1- t) Hg in Enteromorphasp. (tag g - l dry wt) Cu in Enteromorpha sp. (/~gg - ~dry wt)

Control station

Town of Rio Grande

1

2

3

4

5

0.067 4-0.02 2.24 4-0.6 2.67 4-0.74 0.1 +0.04 36.17 4-3.76

0.048 4-0.04 2.06 4-0.58 2.5 4-0.83 0.068+0.02 27.17 4-3.79

0.047 4-0.04 2.04 4-0.55 2.34 4-0.72 0.0534-0.02 28.14 4-3.5

0.043 + 0.04 1.97 ±0.53 1.62 4-0.76 0.0274-0.02 28.13 4-3.44

o. 164 4- 0.05 2.45 4-0.53 2.79 4-0.83 0.0284-0.02 27.64 5:3.38

at R i o G r a n d e , p r o b a b l y d u e to industrial a n d p o r t activities, thus d e m o n s t r a t i n g t h a t low f r e q u e n c y w a t e r s a m p l i n g in v a r i a b l e estuarine situations yields i n a d e q u a t e d a t a to e v a l u a t e the l o w level a n t h r o p o g e n i c c o n t r i b u t i o n o f metals to this estuary.

Laborat6rio de BOtanica Marinha, U L R I C H SEELIGER ROSANGELA Departamento de Oceanografia, B R A GA K N A K Universidade do Rio Grande, Caixa Postal 474, 96.200 Rio Grande, R S Brasil.

Mouth of estuary

Stations

Brooks, R. R., Presley, B. J. & Kaplan, I. R. (1967). APDC-MIBK extraction system for the determination of trace elements in saline waters by atomic-absorption spectrophotometry. Talanta, 14, 809-816. Fuge, R. & James, K. H. (1974). Trace metal concentrations in Fucus from the Bristol Channel. Mar. Pollut. Bull., 5, 9-12. Knak, R. B. & Seeliger, U. (1982). Revis~o e recomendaq~es para anitlise de mercflrio e cobre no ambiente marinho e estuarino. Atlrntica, Doc. Teen. No. 3. Smith, R. C. & Windom, H. L. (1972). Analytical handbook for the determination of As, Cd, Co, Cu, Fe, Pb, Mn, Hg, Ni, Ag, and Zn in the marine and estuarine environments. Georgia Marine Science Center. Tech. Rep. Ser. No. 72-6. (unpublished manuscript). Windom, H. L. (1976). Geochemical interactions of heavy metal in south-eastern saltmarsh environments. US Environmental Protection Agency EPA- 600/3-76-023.

0025-326X/82/070254-02 $03.00/0 Pergamon Press [tO.

Marine Pollution Bulletin, Vol. 13, No. 7, pp. 254-255, 1982. Printed in Great Britain.

Heavy Metals in Sea Turtles Little is r e c o r d e d a b o u t e n v i r o n m e n t a l c o n t a m i n a n t s in reptiles (Hall, 1980), a n d o n l y o n e p a p e r seems to h a v e been p u b l i s h e d o n h e a v y m e t a l s in sea turtles ( S t o n e b u r n e r et al., 1980). T o test the feasibility o f a detailed study, a pilot was r u n using b o n e a n d b a r n a c l e samples f r o m sea turtles. T h e analysis u s e d three samples o f b o n e , all f r o m h u m e r i o f a d u l t c h e l o n i i d turtles, a n d a piece o f an encrusting barnacle, Chelionibia testudinaria (L), f r o m the b e a k o f an O l i v e Ridley, Lepidochelys olivacea (Eschscholtz), collected in J u l y 1981 at M a n t a , E c u a d o r . A digestion t e c h n i q u e similar to t h a t u s e d by G o l d s m i t h & S c a n l o n (1977) o n small m a m m a l s was used in this analysis. T h r e e i n d i v i d u a l b o n e samples were cleaned, d r y - a s h e d at 4 0 0 ° C for 12 h in a m u f f l e f u r n a c e , t h o r o u g h l y m i x e d , a n d e a c h s a m p l e was p a r t i t i o n e d i n t o three subsamples, w h i c h w e r e w e i g h e d a n d

digested with 20 m l o f c o n c e n t r a t e d H N O 3, cooled, diluted with distilled w a t e r a n d 1 ml o f c o n c e n t r a t e d HC1 a n d e v a p o r a t e d to n e a r dryness. Distilled w a t e r was a d d e d to reconstitute the subsamples, w h i c h were t h e n filtered a n d diluted to 50 ml. T h e b a r n a c l e s a m p l e was analysed in entirety b e c a u s e o f its small mass. A n a l y s i s was p e r f o r m e d by f l a m e a t o m i c a b s o r p t i o n o n a P e r k ± n - E l m e r M o d e l 360 s p e c t r o p h o t o m e t e r and b l a n k s w e r e run for each o f the elements m e a s u r e d . Zinc a n d i r o n levels in b o n e a n d b a r n a c l e s are greater t h a n c o p p e r , m a n g a n e s e a n d lead levels (Table 1). This is consistent with the findings o f S t o n e b u r n e r et al. (1980) w h o w o r k e d w i t h egg yolks in loggerheads. L e a d levels, h o w e v e r , are relatively high in o u r samples, w h i c h was n o t so in the egg yolks. N o n e t h e l e s s , it is difficult to interpret the significance o f these findings because so little is k n o w n a b o u t baseline levels a n d physiological effects o f heavy metals in these a n i m a l s . T h e r e is a great need for basic

TABLE 1

Preliminary results of atomic absorption analysis for heavy metals (tag g - 1 ash weight) in three bone and a barnacle sample from sea turtles, mean ( 4- S.D.) and range (in parentheses) for triplicates (with some exceptions where fewer subsamples were used). Sample Bone Bone Bone Barnacle 254

Mn

Fe

Cu

Zn

8.4 + 1.70 (7.2 - 9.6) 35.67 4- 2.08 (34.0 - 38.0) 33.5 4- 2.12 (32.0 - 35.0) -

78.5 ± 27.78 (57.5 - 110.0) 198.3 4- 8.62 (189.0 - 206.0) 309.0 4- 61.73 (268.0 - 380.0) 105.0

9.1 + 2.69 (7.2 - 11.0) 8.6 4- 1.70 (7.3 - 9.7) 8.9 4- 1.63 (7.7 - 10.0) 18.0

575.0 815.0 _ 955.0 46.0

Pb 41.5 + 3.54 (39.0 - 44.0) 86.6 :i_ 12.02 (72.7 - 94.0) 97.2 ± 11.28 (88.6 - 110.0) 68.0

Volume 13/Number 7/July 1982

descriptive studies. Our work in progress may help to fill this void and stimulate similar studies.

Biology Dept., Millersville State College, Millersville, PA 17551, USA Dept. of Zoological Research, US National Zoological Park, Smithsonian Institution, Washington DC20008, USA

S. A. WITKO WSKI

J. G. FRAZIER

Tanker Accidents Analysed Maritime Oil Tanker Casualties--Analysis of Safety and Policy Issues 1964-1977. R. Peterson, Report No. R212 of Netherlands Maritime Institute, P.O. Box 1555, Rotterdam, 1981. 224 pp. Price DF1 95. This well-produced A4-size paper-backed report contains 8 sections as follows, an outline of the study, the relevant data sources, the methodology, the statistical analysis, then in addition to the quantitative section there is a section on relevant qualitative material, and also a section on the international environment, the whole rounded off with a conclusion and recommendations. There is also a very full bibliography and five very useful appendices. In fact the whole presentation has the flavour of an academic dissertation. In an attempt to locate causes and trends, only serious casualties (structural damage, loss of life or pollution) are investigated in this report. This is not such an easy exercise as at first sight it may appear to be, since existing casualty reports sometimes lack detail on the principal headings of size of vessel, flag nation, age of vessel, and location of incident. This is because for a large number of nations, reports are voluntary rather than statutory, and there are many vested interests. Thus the data which are available have an inevitable bias. Bearing in mind this limitation, the data as available are assembled and handled in a systematic manner, and cross checks have been conducted with rigour, e.g. trend analysis by means of linear regression, " t " tests and " s " tests for significance, and Ranked Sum Sign tests for relationships. No empirical level of statistical significance is set and the reader is left to draw his own conclusions from small samples. This is deliberate policy on the part of the author, as he says that he does not wish small samples to be rejected out of hand as they contain much useful information. It can be said, then, that the real objective of this study is to provide an elevated research base upon which other researchers can base further investigations. The study makes the point very well that there is no doubt that the lack of information from which to evaluate the pollution risks that are presented by the maritime carriage of hydrocarbon products is one of the major problems of modern society. Hence pressure is being put on governments to produce reports. However, many of

Goldsmith, C. D. Jr. & Scanlon, P. F. (1977). Lead levels in small mammals and selected invertebrates associated with highways of different traffic densities. Bull. envir. Contam. Toxic., 17, 311-316. Hall, R. J. (1980). Effects of environmental contaminants on reptiles: a review. Special Scientific Report-Wildlife No. 228, U.S. Dept. Int. Stoneburner, D. L., Nicora, M. N. & Blood, E. R. (1980). Heavy metals in loggerhead sea turtle eggs (Caretta caretta): evidence to support the hypothesis that demes exist in the western Atlantic population. J. Herp., 14, 171-175.

these government-produced reports are non-academic in nature and are received with suspicion as they are either at the worst laced with political content, or at the best produced by the parties involved in the regulatory process. For instance, many pollution cases are merely listed under the heading of collision, since this was in fact the prime cause for the complete loss of the vessel. In spite of these difficulties, in this study Table 1.3 does give the sizes of oil spills that resulted from the 220 recorded tanker losses between 1964 and 1977, and it comes up with the somewhat surprising conclusion that structural failure of the vessel is the single largest cause of pollution damage (28.5%) of the total 1.7 million tons, although this in itself is only about 4% of the oil that enters the oceans of the world. It is, however, the factor that causes the greatest public concern because of its concentrated discharge, and nature's inability to deal with this type of problem. The study starts in 1964 because prior to that date tankers were more or less homogeneous so far as size was concerned, so no meaningful conclusions could be reached regarding size of vessel in connection with incidents prior to this date. It can of course be argued that the period from 1964 to 1977 is not long enough to develop worthwhile trend lines using the least squares method of regression. The main hypotheses tested in the report were the relationships between accident frequency and the following five factors: tanker size, tanker age, nation of registry, location of casualties, and nature of ownership. It must be remembered by the ecologist who reads this report that the conclusions reached therein are based upon data related to total losses of tankers. In addition to these reported incidents, pollution can, and indeed does, occur quite extensively from partial losses and otherwise apparently trivial incidents and minor negligence. Other limitations of this study are pointed out by the author in the text, for example, the fact that data obtained from the UK Tanker Safety Group does not exactly match the time scale of the data used for the main study. It is, however, used in regression analysis in order to determine trends. The trend obtained from these data is the same as that from the main data source, though naturally the level of significance is different. However, the alarming fact is that it is an upward trend over the period of the study. A useful part of this report for the operator of marine craft is the non-statistical data culled from the 41 accident investigation reports and other sources, from which human error was found to account for 68.3% of accidents. The conclusion of 'human error' which is now

255