Volume 32/Number 1 l/November 1996

Edited by D. J. H. Phillips

The objective of BASELINE is to publish short communications on different aspects of pollution of the marine environment. Only those papers which clearly identify the quality of the data will be considered for publication. Contributors to Baseline should refer to ‘BaselineThe New Format and Content’ (Mar. Pollut. Bull. 24, 124).

Marine Pollufion B&fin, Vol. 32. No. 11, pp. 823427, 1996 Pergamon Copyright 0 1996 Elwicr Science Ltd

Printed in Great Britain. All rights resewed

Long Term Variability in Pollutant Concentrations in Coastal Sediments from the Ninety Mile Beach, Bass Strait, Austrdia DAVID HAYNESI, PHILIP RAYMENTt and DAVID TOOHEY*$ *Gippsland Water, P.O. Box 348, Traralgon, Victoria 3844, Australia tA4onash University, Gippsland Campus, Switchback Road, Churchill 3842, Australia SPreseni address: Research and Monitoring, Greai Barrier Reef Marine Park Authority, P.O. Box 1379, TownsviNe 4810. Australia #Present address: Envirogen. P.O. Box 1956, Traralgon 3844. Australia

Sediments are usually regarded as the ultimate sink for persistent pollutants discharged into the environment (Gibbs, 1973), and are one of the best media for the long-term monitoring of many contaminants (Larsen & Jensen, 1989). Short-term temporal (daily, monthly or yearly) variations in pollutant concentrations in sedi- ments have been described for metals (Morrisey et al., 1994; Haynes et al., 1995a), and dioxin concentrations (Mosse & Haynes, 1993) in Australian marine areas. However, little information is available for longer-term variations in the concentrations of these pollutants in sediments. This report presents the results to date of a monitoring programme to assess longer-term temporal and spatial variablity in metal, dioxin and extractable organohalogen (EOX) concentrations in sediments. This programme is designed to assess the potential long-term impact of a nearshore discharge of a secondary-treated complex effluent containing pulp and paper, industrial and domestic wastewaters, and oil and gas formation waters. These may affect the subtidal sediments along the Ninety Mile Beach, Bass Strait, Victoria, Australia. This ocean discharge commenced in June, 1992.

The sediment sampling design for metals incorpo- rated three spatial scales, involving approximately 3 m between sample replicates, 30 to 100 m between

sampling stations and tens of km between sampling locations at the Delray Beach outfall site, and control locations at Woodside and Seaspray Beaches (Fig. 1). Two 5 kg replicate samples of sediment were collected in acid-washed plastic containers from four randomly- located sites within a 0.4 km2 area at each location. Sediments were collected on two occasions prior to the commencement of effluent discharge (June, 1991 and May, 1992), and on five occasions after this (October, 1992; May and October, 1993; and May and October, 1994). All samples were collected by divers from the top 5 cm of the sea-bed between 1.5 and 3.5 km offshore, in a water depth of approximately 16 m; collected sediments were frozen within 12 h. Prior to analysis, the frozen sediments for metal analysis were thawed and wet-sieved through a 63 um nylon mesh. The fraction passing through the mesh was split into two portions and freeze-dried in polythene Whirl-pats. A nitric/ perchloric acid digest (Anon., 1984) was carried out on one portion for the determination of Cd, Cr, Cu, Pb and Zn. The concentrations of acid-digestible (total) Hg present in the fine (< 63 urn) sediment fractions were determined following a concentrated nitric/hydrochloric acid digestion procedure (Ehick & Horowitz, 1987). Full methodological details are provided elsewhere (Haynes et al., 1995a). Blanks and Certified Reference Materials (National Bureau of Standards Standard Reference Material 1646 Estuarine Sediment; Commu- nity Bureau of Standards Certified Reference Material CRM 277; and National Research Council Certified Reference Material Marine Sediment PACS-1) were analysed concurrently with the sediment samples, to ensure consistency of recoveries over the sampling period (Table 1). A two-way (Model 1) hierarchical analysis of variance (ANOVA) was used to compare metal concentrations in the < 63 pm fraction over time, and between sampling locations. Data collected in autumn (June, 1991, May, 1992, May, 1993 and May, 1994) were compared in one set of analyses, and data collected after May, 1992 (October, 1992, May and October, 1993, May and October, 1994) were compared in a second set of analyses. In the model, sampling time and location were treated as fixed effects, and the stations (within times and locations) as random effects. This two-step analysis was carried out to simplify data comparisons and to enable any seasonal variation in the results to be assessed. Residual plots were inspected for gross deviations from normality, and were logi,,- transformed where necessary before analysis. Cd concentrations were less than the detection limit ( < 2 ugg-‘) for a majority of the analysed samples, and could not therefore be statistically tested. All computa- tions were carried out using the MINITAB (release 10) statistical package.

The temporal and spatial variability in sediment metal concentrations is presented in Fig. 2. Significant spatial and/or temporal differences existed in the

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Marine Pollution Bulletin

39s- 148E

Pig. 1 Sediment sampling locations, Ninety Mile Beach, Victoria. W: Woodside Beach; S: Seaspray Beach; D: Delray Beach (outfall location).

TABLE 1

Mean recoveries of sediment standards. All concentrations as pgg -’ dry weight. Data in parentheses for Standard Reference Materials are standard deviations around certi6ed mean values.

cadmimn chromimn Copper Lead Mercury Zinc

SRM’ 0.36 (0.07) June, 1991 0.36 May, 1992 0.34 Ckt, 1992 0.22 SRM’ 11.9 (0.4) May, 1993 10.8 act, 1993 11.9 May, 1994 12.6 SRM’ 2.38 (0.2) act, 1994 2.5

76 (3) 53 38

1;; (7) 150 211 193 113 (8) 130

18 (3) 15 15

1:;.7 (1.6) 82 82

4;; (16) 440

28.2 (1.8) 0.063 (0.012) 138 (6) 20 0.068 NA 17 0.064 NA

1: (3) 0.075 1.77 (0.06) NA 547 (12) 119 1.74 416 113 1.76 NA 111 1.70 NA 404 (20) 4.57 (0.16) 824 (22) 420 4.6 830

‘National Bureau of Standards Standard Reference Material 1646, Estuarine Sediment; 2Community Bureau of Standards Certified Reference Material CRM 277; ‘National Research Council Certified Marine Reference Sediment PACS-1.

NA: Not available.

concentrations of all metals analysed in sediments Single composite 3 kg sediment samples were also collected in autumn between 1991 and 1994, with Pb collected in solvent-washed glass containers from eight as the single exception (Table 2) and in sediments randomly-located stations at the three sampling loca- collected after May, 1992 (Table 3). There were also a tions on each survey (Fig. 1). These unreplicated number of significant interaction terms present. The samples were used for analyses of organic contam& absence of any consistent temporal or spatial pattern in nants. The samples were thawed and divided into two sediment metal concentrations over the four year subsamples, one of which was analysed for extractable sampling period implies that the Delray Beach ocean organohalogens (EOX), and the other for dioxins. The outfall discharge is not exerting a detectable impact on analyses for EOX were carried out by Aquatech Pty background metal concentrations in sediments in the Ltd, University of South Australia, and involved vicinity of the discharge. However, other changes of blending the sediment sample to ensure homogeneity. statistical significance have occurred in metal levels in This was followed by extraction of approximately 50 g sediments in the study area over this period. of sample with a petroleum spirit-acetone mixture,

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Volume 32/Number 1 l/November 1996

4 200

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Fig. 2 Temporal and spatial variations in sediment metal concentra- tions. AU metal concentrations as pgg-’ dry weight (n=8, error bars = 1 SEM). Samples were not collected in October, 1991.

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Marine Pollution Bulletin

TABLE 2 ANOVA F ratios, autumn samples only (1991-1994 inclusive).

Source of variation chromium Copper Mercury Lead

Year Location Year x Location Station (Year, Location)

46.51*** 13.23*** 9.03*** 1.70 2.62 3.82+ 6.72+* 0.17 1.10 2.34 3.31 4.47*+* 3.35*** 1.27 2.50** 2.50**

*0.01 <p < 0.05, **0.001 <p < 0.01, ***p < 0.001.

TABLE 3 ANOVA F ratios, post-discharge sampling (October, 1992--October, 1994).

Source of variation chromium Copper Mercury Lead Zinc

Sampling Time Sampling Location Time x Location Station (Time, Location)

52.07*** 4.20** 4.86** 15.34*** 4.50** 2143 12.22+** 24.69+** 0.23 7.26+* 3.87** 4.42*++ 3.11 1.61 2.63* 4.21*** 1.59* 2.01+* 7.42*** 1.17

*0.01 <p < 0.05, ??*0.001 <p < 0.01, ***p < 0.001.

followed by phase separation, dehydration of the extract with sodium sulphate, and its concentration. Detection of organohalides was performed with a Euroglas Total Organic Halogen Analyser, Model ECS 1000 (Anon., 1990). This procedure provided a detection limit for EOX of approximately 0.01 mg kg-’ sediment by wet weight. Sediment samples spiked with 4800 pg kg-’ hexachlorobenzene and determined as EOX gave 96% ( f 5%) recoveries.

Temporal and spatial variations in EOX concentra- tions in sediments from the Ninety Mile Beach are presented in Fig. 3. Concentrations of EOX ranged from 0.02 to 0.11 mg Cl kg-’ dry weight, and concentrations present at all three sampling sites were similar to those found in nearshore sediments in the vicinity of Adelaide and Sydney (Nichols & Espey, 1991). No detectable difference (two-way, unreplicated ANOVA) was present in sediment EOX concentrations between samplink times (F3,15 = 2.07, p = 0.147). Sig- nificant differences were detected between sampling locations (Q = 4.23, p=O.O35), with the Woodside

0.16

c 0.10

g

!

@ 0.06

??CMray ??Seaspray ??woodslde

Sampling dab Fig. 3 Temporal and spatial variations in sediment EOX concentra-

tions (pg g- ’ dry weight). Samples were not collected in October, 1991.

location consistently exhibiting the lowest sediment EOX concentrations over most of the sampling period.

Sediment samples for dioxin analysis were dispatched (frozen on ice) for analysis to the Institute of Environmental Science and Research (previously the Institute of Environmental Health and Forensic Sciences), Lower Hutt, New Zealand. The analyses of polychlorinated dibenzodioxins (PCDDs) and their furan counterparts (PCDFs) were carried out as described by Buckland ef al. (1990). The sample was spiked with 13C-labelled standards, extracted with organic solvents, and purified with chemical treatment and solid phase chromatographic techniques. Measure- ment was performed using high resolution gas chromatography, with high resolution electron impact mass spectrometry. Further methodological details are available from the Institute of Environmental Science and Research. Differences in detection limits over time and between samples resulted in a range of detection limits being reported for individual PCDD and PCDF congener concentrations over the study period. Where this occured, all results which were less than the detection limits for a particular congener were set at the highest detection limit reported over the study period for that particular congener (Haynes er al., 1995b). This enabled comparisons to be made between samples. The ranges of dioxin congener concentrations detected in sediments are presented in Table 4. With the exception of the non-2,3,7,8-HxCDD and several hepta- and octa-substituted species, the individual congener concentrations in sediments were below detection limits at all sites, both before and after the commencement of the effluent discharge. There was no detectable increase in any congener concentrations at the Delray outfall site following commencement of the effluent discharge.

The authors wish to thank Deb Clarke and Ruth Knight (Gippsland Water) for assistance with metal analyses. Sediment EOX analyses were carried out by G. Levay (University of South Australia) and sediment dioxin determinations were carried out by the Institute of Environmental Science and Research Limited, Lower Hutt, New Zealand. Peter Masse (Gippsland Water) is thanked for critically reviewing the manuscript.

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Volume 32/Numbe.r 1 l/November 1996

TABLE 4

Range of PCDD and PCDF congener concentrations* present in sediments collected from the Ninety Mile Beach, May 1991 to October 1994. (All concentrations as pgg-’ wet weight.)

Time Woodside (control)

PRE-DIS POST-DIS pRE,p (control)

POST-DIS Delray (outfall)

PRE-DIS POST-DIS

No. samples 2 2378 TCDF <O.l 1278 TCDF < 0.05 Non 2378 TCDF <O.l 2378 TCDD < 0.2 Non 2378 TCDD < 0.3 12378 PeCDF < 0.07 23478 PeCDF < 0.07 Non 2378 PeCDF < 0.07 12378 PeCDD <O.l Non 2378 PeCDD < 0.2 123478 HxCDF < 0.2 123678 HxCDF < 0.4 234678 HxCDF < 0.2 123789HxCDF < 0.4 Non 2378 HxCDF < 0.2 123478 HxCDD < 0.3 123678 HxCDD < 0.2 123789 HxCDD < 0.2 Non 2378 HxCDD 0.46-0.56 1234678 HpCDF < 0.3 1234789 HpCDF < 0.4 Non 2378 HpCDF < 0.3 1234678 HpCDD 0.59 Non 2378 HpCDD 0.67-1.2 QCDF 0.4 QCDD 5.15-12.4

5 <1 < 0.6 <1 <1 <1 < 0.7 <0.9 < 0.9 <1 cl < 0.9 < 0.9 < 0.9 <2 < 0.9 <l <l <l <l <l <1 <l <l <2 <4 <30

2 < 0.06 < 0.03 < 0.06 < 0.08 < 0.2 < 0.04 < 0.04 < 0.04 < 0.06 < 0.2 < 0.07 <O.l < 0.09 < 0.2 < 0.07 < 0.2 <O.l <O.l

0.75-0.83 < 0.07-0.34 < 0.2 <0.07-0.18

0.36-0.83 1.35-1.8

< 0.7 11-16

5 <0.6 <0.3 <1 < 0.6 < 0.6 < 0.3 <0.3 <OS <0.5 < 0.7 <0.5 < 0.4 < 0.6 <l <0.5 < 0.6 < 0.6 < 0.6 < 0.9-l .95 < 0.8 < 0.4 < 0.7 < 0.6-1.03 < 2-2.73 <1 <30

2 5 < 0.2 <l < 0.05 < 0.5 < 0.2 <2 < 0.3 < 0.9 < 0.4 < 0.9 <O.l < 0.6 <O.l < 0.8 <O.l <0.8 < 0.2 < 0.3 < 0.2 <0.5 < 0.2 < 0.6 < 0.2 < 0.4 < 0.5 < 0.4

1.09-1.9 < 0.4

4.8 < 0.4

0.36-1.3 1.34-3 1-2

12.2-26.2

< 0.9 < 0.9 <0.8 < 0.7 < 0.9 <2 <2 <l <l <l <2 <l <l <l <2 <3 <3 <40

*The < values represent the maximum detection limit for the particular congener group and can therefore be interpreted as non-detection for that congener group for the sampling period. Qther vahtes are the quantified minimmn and maximum concentration of the congener detected in collected sediments over the study period.

Anon. (1984). Digestion Procedures for the Determination of Heavy Haynes, D., Mosse, P. Jc Oswald, L. (1995b). The use of transplanted, Metals by Atomic Absorption Spectrophotometry and ICP cultured mussels (Mytilus edulis) to monitor pollutants along the Emission Spectroscopy. Unpublished Report of the Rural Water Commission, Armadale, Victoria, Australia.

Ninety Mile Beach, Victoria, Australia II. Polychlorinated dibenxo-

Anon. (1990). Micro-coulometer for all Organic Chlorine Measure- pdioxins and dibenxofiuans. Mar. Pollut. Bull. 30, 834-839.

merits: Design and S’ct$cation Booklet. Eur~glas BV, Delft, The Larsen, B. & Jensen, A. (1989). Evaluation of the sensitivity of Netherlands. sediment stations in pollution monitoring. Mar. Pollut. Bull. 20,

Buckland, S. J., Hannah, D. J. & Taucher. J. A. (1990). 556-560. Polychlorinated dibenxo-P-dioxin and dibenx&&n concentrations in New Zealand’s Hector’s dolphin. Chrmospihrrc 20, 1035-1042.

Morrisey, D. J., Underwood, A. J., Stark, J. S. & Howitt, L. (1994).

Ehick. K. A. & Horowitz, A. J. (1987). An&s& of Rocks und Temporal variation in concentrations of heavy metals in marine

Sediments for Mercury by Wet Digestion and Fkvneless Cold Vapour sediments. Estuar. Coastal Shelf Sci. 38, 271-282. Atomic Absorption (~a&zn Notes, No. AA-72). Varian Analytical Mosse, P. & Haynes, D. (1993). Dioxin and furan concentrations in Instruments, Palo Alto, CA, USA.

Gibbs, R. J. (1973). Mechanisms of trace metal transport in rivers. uncontaminated waters, sediments and biota of the Ninety Mile

Science 180, 71-72. Beach, Bass Strait, Australia. Mar. Pollut. Bull. 26, 465467.

Hay-ties, D., Toohey, D. & Mamey, D. (1995a). Temporal and spatial Nichols, P. D. & Espey, Q. I. (1991). Characterization of organic

variation in background concentrations of trace metals in coastal matter at the air-sea interface, in the subsurface water, and in sediments from the Ninety Mik Beach, Victoria, Australia. Mar. bottom sediments near the Malabar sewage outfall in Sydney’s Pollut. Bull. 30, 414-418. coastal region. Aust. J. Mar. Freshwat. Res. 42, 327-348.

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