Of Bioavailable Metal Contamination Across South Australia Using Translocated Mussels Mytilus Galloprovincalis

Transactions of the Royal Society of South Australia (2011), 135(1): 39–54 AN ASSESSMENT OF THE CURRENT STATUS OF BIOAVAILABLE METAL CONTAMINATION ACROSS SOUTH AUSTRALIA USING TRANSLOCATED MUSSELS MYTILUS GALLOPROVINCALIS S. GAYLARD1, S. THOMAS1, AND M. NELSON1 South Australian Environment Protection Authority, GPO Box 2607 Adelaide, South Australia 5001 1 – corresponding author, GPO Box 2607 Adelaide, South Australia 5001 Fax: +61881244673 Abstract This study presents results from the first regional assessment of metal levels in translocated blue mussels (Mytilus galloprovincialis Lamarck, 1819) in the nearshore coastal environment across South Australia. A total of 422 replicate samples of translocated mussels were deployed throughout 11 regions across the South Australian near shore marine environment. Mussels were recovered after approximately 70 days and analysed for total metal load in the flesh of the mussel. Results showed vast differences in metal concentrations between different regions and also compared to the baseline metal concentration. Many of these differences can be attributed to the level of industrial activity in the regions which may have implications for environmental regulation in these regions. KEY WORDS: Mytilus galloprovincialis, lead, cadmium, mercury, biomonitor, industrialisation. Introduction Spatial and temporal monitoring of levels and trends of metals and other contaminants in the coastal environment using bivalve mussels as bio-monitors is well established since Goldberg (1975) proposed the concept. Metals accumulated in the mussel tissues represent a time integrated response to bioavailable metals, where the concentration may be several orders of magnitude higher than what would be found in seawater [Phillips and Rainbow, 1993; Rainbow, 1995]. Using this time integrated approach can reduce the frequency and cost of analysis and can also produce results which are less likely to be affected by analytical limits of reporting or by frequent changes in dissolved concentrations which may vary on each tidal cycle or season [Rainbow, 1995]. Importantly using biological indicators of the available fraction of metals in the marine environment is of direct ecotoxicological relevance [Phillips and Rainbow, 1993; Boening, 1999] and is preferable to other methods where the sampling and/or chemical analysis method artificially define the bioavailable fraction. State- or country-wide monitoring programs using field-collected or translocated mussels have been underway in many locations since the early 1980s either as Government funded “state of the environment” style programs e.g.: Mussel Watch in the National Status & Trends program US NOAA: [Farrington et al., 1983; O’Conner, 1996], or the French Reseau National d’Observation de la Qualité du Mulieu Marin [Beliaeff et al, 1998] or Biointegrator network (RINBIO) [Andral et al., 2004]. Alternatively specific studies have been conducted to investigate known or suspected contamination issues via research bodies [Ward et al., 1986; Jamil et al., 1999; Chou et al., 2003]. The uptake and hence bioavailability of metals in the marine environment by a biomonitor is highly dependant on a number of geochemical and biological factors. The geochemical factors that can affect bioavailability include the concentration of organic carbon, water hardness, salinity, temperature, pH, dissolved oxygen and hydrologic features of the particular environment [Boening, 1999]. These parameters may vary between regions which may contribute to spatial variability. The biological factors that can influence the uptake of bioavailable metals are significant between bivalve species [Beliaeff et al., 1998]. This issue can be somewhat overcome by using a standardised or cosmopolitan species such as Mytilus spp. [Rainbow, 1995]. Even within the same species variability can occur through different ages, sex and reproductive state [Boening, 1999]. Translocating mussels from an area such as a commercial lease where the age and reproductive state are known and homogeneous can help to alleviate some of the variability seen within the same species [Fabris et al., 1994]. 39 S. GAYLARD, S. THOMAS, & M. NELSON South Australia’s nearshore coastline is varied both hydrodynamically and geomorphologically. There are two large inverse estuaries which reduce flushing with the open ocean [Petrusevics, 1993; Nunes Vaz et al., 1990], numerous large embayments and open southern ocean. The city of Adelaide, with its 1.1 million people [ABS, 2007], lies on the eastern shores of Gulf St Vincent (Figure 1) is the major population centre in South Australia and there are numerous smaller towns, the majority of which are located on the coast. There are a number of potential sources of metals into the nearshore coastal environment in South Australia. The most significant of these is a lead/zinc smelter at Port Pirie located in the north of Spencer Gulf and also the city of Adelaide located on the eastern side of Gulf St Vincent (Fig. 1). Significant metal accumulation and biological effects within the coastal waters surrounding Port Pirie have been well documented over the last 30 years [Ross et al., 2002; Edwards et al., 2001; Ward & Hutchings, 1996; Ward et al., 1986; Ward & Young, 1981]. Other potential sources of metals across South Australia include wastewater treatment plants, urban and agricultural runoff, heavy industry and atmospheric deposition. Like most locations throughout Australia coastal towns are experiencing a large amount of development in close proximity to the coast. To date there has been little documented assessment of metal levels or quantification of risk in all regions of South Australia, with the exception of Port Pirie, other than a small number of desktop risk assessments or specific pollution event driven investigations [Gaylard, 2009; Bryars et al, 2006; Mortimer, 2004; Westphalen et al., 2004]. The aim of this study is to assess regional water quality rather than investigating specific sources of metal pollution. Mussels have been used in this survey as biomonitors to assess the metal status of the marine environment, not to determine whether the concentrations of metals recorded in the environment are adversely affecting the Mytilus galloprovincialis that have been exposed. This monitoring is designed to provide information to quantify the risks from heavy metals on a regional scale in South Australian coastal waters as this may affect the level of regulation exerted on each of the sources in the regions. Methods A large proportion of South Australia’s nearshore coastal environment was sampled throughout this study. In order to make regional assessments of metal levels the state was arbitrarily divided into 11 regions based on potential risk factors, hydrodynamics and logistical constraints. A total of 422 replicates were sampled across 11 regions throughout South Australia’s nearshore coastal waters (Fig. 1). At each replicate location within each region, nylon bags containing 10 mussels were placed in the water using a clean “Besser block” weight on a polypropylene rope to maintain its position. Each replicate analysis was taken from the 10 organism pooled which has been shown to provide an excellent estimate of the population mean generally with a lower variance than the population variance [Gordon et al, 1980]. The bags were suspended approximately 2 m below mean low water mark using a 100 mm sub-surface float and marked by GPS. The number of replicates within each region varies according to the perceived level of contamination which was assessed prior to deployment. Studies have shown that disturbed areas can be more variable than undisturbed and as such sample size is often needed to be higher in order to find differences (whether in means or variances) between regions [Fraterrigo and Rusak, 2008; Fairweather, 1991]. In some areas replicate numbers are lower than anticipated due to a number of replicates being un- recoverable or lost. All regions, with the exception of the South East indicated significant differences for a number of metals (see later) indicating that there was sufficient power to detect a difference at the 0.05 level. There were a number of replicates that were not recovered from the South East which greatly reduced the sample size in this region. This is likely to have adversely influenced the power to detect a difference between this location and others. The higher wave energy typical of this region is likely to be a contributing factor to the loss of replicates in this region. Mussel sampling Mussels (Mytilus galloprovincialis, Lamarck 1819, length µ=85.3 mm σ=5.8 mm) were obtained from a commercial mussel aquaculture lease located approximately 10 km from the township of Port Lincoln on South Australia’s Eyre Peninsula (Figure 1). On receipt of each 20 kg batch of mussels a sub-sample of 40 STATUS OF METAL CONTAMINATION USING TRANSLOCATED MUSSELS MYTILUS GALLOPROVINCALIS 1 11 .. WHYALLA 1'i;--- ~ PORTPIRIE Study Area \j E EE COFFIN BAY D o-"% , 0/o PORT LINCOLN > .; / Yorke Peninsula GAWLER ~ A~ ELAIDE Port River Adelaide North ---.. ~ j 1\ t: '"' - ADELAIDE Adelaide 0 50 100 150 200 250 Km Central # , X Adelaide X So"th ---------. , KINGSCOTE 1% McLAREN VALE # X # Built Up Area I Figure 1. Map of 87 mussel locations within 11 regions across South Australia. 41 S. GAYLARD, S. THOMAS, & M. NELSON mussels (n=20) were sent to the laboratory for metal analysis to establish a baseline. All mussels were deployed between February-March 2008 and February-March

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