Mannc Pollution Bu~e~cm

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MaRne P~.llution Bulletbt Vo l . I7, No, 7, pp. 332-333, 1986, Printed m Great Britain

3025-326X; g6 S3.0t TM] L'~3 C 1986 Pergamon Journals L~cl.

Metals in Seawater off Trinidad, West Indies

TABLE 1

Precision for metal determinations as measured h,.. relative standard deviation. Average values in gg 1 -~ (n=5)

Monitoring of Fe, Mn, Cr, Ni, Cu, Pb and Cd levels in seawater was conducted in the vicinity of a proposed Fc industrial site over a 3-year period. The industrial site is Cu located along the western coastline of the island of Cr

Mn Trinidad (61-61!°W longitude; 10~°N latitude) (Fig. 1). Ni The major objective of the monitoring programme was Pb

the acquisition of baseline information prior to the Cd commencement of industrial activity.

37 2£I ~-,-~ INumbefecl ~-~nsect staLions

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Fig. 1 Map of area sampled.

km o I L t

Metal Average relative standard deviation

915.4_+.2.8% 8.0 ± 3.0% 1.6 ± 1.0%

40.4 + 3.6% 2.0 _+.* 6.0%

14.0 _ 7.6°6 1.7 ± 2.5%

As expected, the stations located closer to the shore had markedly higher average Fe concentrations than the corresponding ones further out (Table 2). Iron is known to show non-conservative behaviour (Demina et al., 1978). The differences in Mn concentrations between the inner stations and the corresponding outer stations were not as great as for Fe because Mn apparently shows conservative behaviour (Holliday & Liss, 1976). For all the other metals the average concentrations were generally similar for the inner and outer stations. Station 5.1 had the highest averages for all metals except Cd most likely because it was located close to a number of already existing industries.

TABLE 2

Average concentrations of metals in seav, ater (gg l -t)

Metal

Station Fe Cr Mn Cu Ni Pb Cd

1.I 1358.0 3.4 54.4 5,9 7.5 7.8 2.9 1.7 419.0 3.7 23.9 4.5 10,6 10.0 2.1 3.1 809.0 4.4 32.8 6.{) S.2 8.1 1.9 3.7 465.0 4.0 20.5 4,7 9,6 9.1 2,3 4.1 1879.0 4.0 42.9 7.0 9.3 8.4 1.5 4,4 228.0 4.6 11.5 5.4 S.S 7.4 1.8 5,1 8751.0 10.8 193.1 14.0 17.0 15.3 2.0 5,5 365.0 2.6 13.2 4.8 8.8 7.9 1.7 6.1 2509.0 7.4 52.3 37.6 102 9.3 1.6 6.4 609.0 3.0 28.0 5.2 11,7 8.4 1.6 9.1 3789.0 3.8 18.3 6.9 8,9 8.4 1.3 9.5 230.0 3.4 18.9 5.2 7,8 6.3 1.t

Filtered seawater samples were preconcentrated with Chelex-100 (100-200 mesh) using the method of Kingston et al. (1978), except that the samples were siphoned from their containers into the columns instead of being passed directly through the columns from inverted containers.

Metal levels in the nitric acid eluates from the chelex columns were determined by atomic absorption spectrophotometry using a Pye Unicam SP 9 spectro- photometer with automatic background correction. The precision of the metal analyses was determined by the relative standard deviations for replicate determinations on a typical seawater sample. The data are given in Table 1.

Those metals which have a high affinity for sulphide (Dryssen & Wedborg, 1980) showed enhanced levels either towards the end of the reclamation period or subsequent to the termination of the reclamation activities. This was apparently due to the oxidative remobilisation of these metal sulphides which accumu- lated in the fill during and after the reclamation period (Jonasson & Timperley, 1974).

L. H A L L

Department of Chemistr?; University o f the West Indies, St. Augustine, Trinidad, W.L

I. CHAz\'G-}E;

3.9,

Volume 17/Number 7/July 1986

Demina, U, Gordeyev, V. & Fomina, L. (1978). Forms of occurrence of Fe, Ma, Zn and Cu in river water and suspended matter and their variation in the zone of mixing of river and sea water (as exemplified by rivers of the Black Sea. Sea of Azov and Caspian Basins). Geochem. Int. 146-163.

Dryssen, D. & Wedborg, M. (1980). In Chemistry and Biogeochemistry of Estuaries. (E. Olausson & I. Cato, eds.) pp. 71-119. Wiley-inter- science, New York.

Holliday, L. & Liss, P. (1976). The behaviour of dissolved iron, manganese and zinc in the Beaulieu estuary, S. England. Estuar. Coast. Mar. Sci., 4,349-353.

Kingston, H., Barnes, T. & Rains, T. (1978). Separation of eight transition elements from alkali and alkaline earth elements in estuarine and seawater with chelating resin and their determination by graphite furnace atomic absorption spectrometry. Anal)st 50, 2064-2070.

Jonasson, I. & Timperley, M. (1974). Field observations on the transport of heavy metals in sediments (A. de Groot & E. Allersma). A discussion. Prog. Wat. TechnoL 8, 97-101.

Toxicity Tests Multispecies Toxicity Testing. John Cairns Jr (ed). Pergamon Press, Oxford, UK 1985 261 pp. Price: $27.50. ISBN 0-08-031936-X.

This useful volume is the record of a symposium held in Virginia, USA in May 1983. The twenty-five contribu- tors were broadly drawn from universities, government institutions and chemical companies, and with two exceptions, were exclusively American. This is a slight drawback for non-American readers because the regulatory aspects of multispecies toxicity testing are discussed in a purely US context, and the American prose has a characteristically indigestible quality. The papers include 'perspectives' of the field, a series of case histories, and several covering cost, standardization, reproducibility and sensitivity of the various techniques. Although the contributions are mainly concemed with freshwater systems, the basic principles and arguments apply equally to marine systems.

Although described by the authors of the excellent synopsis as a ~orkshop', this 3-day meeting apparently did not have time for a full discussion of the issues raised. Perhaps this reflects the failure to agree on many fundamental issues, even extending to a definition of what exactly constitutes MTT. For example, one partici- pant restricted his definition to laboratory microcosms, whereas most workers would certainly include controlled field-scale tests. The synopsis confines itself to "any test which has a level of organization higher than that of a single species" which is not very satisfactory. The important factor is that for MTT to have a value greater than single species tests, it should involve inter- acting populations, including at the very least a producer species, a consumer species and a decomposer species.

Other points of disagreement concern the value of MTT for regulatory and industrial decision-making, definition of endpoints in a system of continuous variables, predictive value when compared with

traditional single-species tests, the degree of 'realism' of artificially constructed systems, and their cost- effectiveness. Such numerous differences of opinion ensure that all the major issues are fully aired in the book.

A consensus of sorts was that MTT is a useful research tool, but nobody was prepared to claim that this suite of techniques is sufficiently well-developed to support regulatory decisions. This is mainly due to the uncertain- ties inherent in complex biological systems, but it could also be connected with the aforementioned American bias of this book. The adversarial assessment of potentially hazardous substances in the United States produces a much more cut-and-dried approach than that found in many European countries, thus ruling out the use of non-standard data with poorly defined endpoints. In contrast, MTT has been useful in some European regulatory decisions, although it can still be argued that traditional testing methods are normally sufficient for hazard assessments.

Some of the most interesting papers describe case studies where the results of traditional tests and ~ on a given substance were compared. For the relatively few chemicals which have been investigated in this way, the no-observable-effect-concentration (NOEC) derived from single-species data is generally within an order of magnitude of the NOEC based on structural changes in test communities. Perhaps surprisingly, MTT can some- times be less sensitive than traditional methods due to many factors including rapid biodegradation, high back- ground noise and insufficient knowledge of the test system's ecology. Possibly the central problem is the inherent conflict between realism and accuracy; as the former increases, the latter declines.

In short, a stimulating book which honestly portrays the deep disagreements about the value of MTT and gives sufficient pointers to the direction of future research in both the freshwater and marine field.

PETER MATTHIESSEN

333