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Trace metal contamination of soils and sediments in the Port Kembla area, , Australia

Yasaman Jafari University of Wollongong

Jafari, Yasaman, Trace metal contamination of soils and sediments in the Port Kem- bla area, New South Wales, Australia, Master of Environmental Science - Research thesis, School of Earth & Environmental Sciences - Faculty of Science, University of Wollongong, 2009. http://ro.uow.edu.au/theses/3133

This paper is posted at Research Online.

Chapter 5 Discussion

This chapter discusses the results of the current study including the grain size and total metal concentration analysis of soil and sediment samples from the Port Kembla area, the extractable concentrations of trace elements in these soils, as well as a comprehensive comparison of these results to previous world-wide studies.

5.1 Sources and Amounts of Trace Metals in Soils and Sediments of the Port Kembla Area. Studies by Beavington (1973), Ellis and Kanamori (1977), Crisp (1981, 1982) and Chenhall et al. (1994) have concluded that the main sources of trace metal contaminants found in Port Kembla area and Lake are industrial discharges, atmospheric depositions of particulate matter especially within a distance of < 4 km from the Port Kembla copper smelter stack (Martley et al., 2004), leaching of soils and other terrestrial deposits, urban pollution, runoff from roads and freeways, and natural weathering of the surrounding rocks. Considering industrial particulate matter, it is believed that recent and historically deposited industrially derived trace metals play a major role in trace metal loading in soils and sediments of the area. Crisp (1981) listed three possible sources responsible for pollution of the area. ƒ Steelmaking: most iron and nickel with some zinc and lead; ƒ Coking: sintering and storage of coke and particulate dust; and ƒ Copper smelting: copper, zinc, lead, selenium, arsenic and antimony. According to Pacheco (1999), significant sources of pollution in the Illawarra, are ERS/Southern Copper/Port Kembla Copper (started 1910), BHP Steel/BlueScope Steel (started 1928), Tallawarra (1954-1989), Kanahooka smelter and three coke works. These pollutant sources, together with urban and automobile contaminants, especially leaded petrol, could have affected the Illawarra. Chiardia et al. (1997) used lead isotopes to identify the historical lead pollution in roof dusts and lagoon sediments of the Illawarra region and found that each of the major sources listed above added to the total pollutant load in the region. Moreover, atmospheric pollution is largely dependant on the

113 prevailing wind, which blows from the west and southwest in winter and from the northeast and south in summer. The extent to which these sources are contributing to trace metal contamination in soils and sediments of the study area will be discussed in this chapter.

5.1.1 Significant Pollutants in Soil Samples Copper, Zinc, Lead and Arsenic distribution: The distribution of Cu concentrations in the soil samples (Figure 4.3) shows significant concentrations of Cu centred upon the Port Kembla copper smelter stack. According to XRF results (Appendix 3) and Figure 4.4 (b), the average value of Cu found in the soil samples of the area is 324 ppm, with a minimum of 39 ppm, maximum of 1636 ppm and a mean enrichment factor of 2. Anomalous samples S58, S33 and S34 have been omitted due to their location in slag dumps (as determined by observation during sampling). Values decrease on moving farther from the stack with the lowest values of Cu observed in the south-western parts of the study area due to their distance from the copper smelter. In agreement with previous studies (e.g., Beavington, 1973, 1975; Martley et al., 2004), the main source of Cu in the Port Kembla Industrial area has been the copper smelter. High levels of extractable Cu were also found within a 1 km radius of the heavy metal smelting plant. It is likely that fine particles blown from copper ore stockpiles contribute considerably to these high levels. Based on the results of Kachenko and Singh (2006), positive linear correlations exist between soil Cu, cation exchange capacity (CEC) and organic carbon, indicating the binding of soil Cu is higher in organic/mineral soils which may lead to greater retention of Cu in the topsoils. Thus, it is believed that the smelter plant at Port Kembla is a probable point of Cu contamination in the region. Minor Cu contaminations would also come from urban pollution, vehicles and other industries. Figure 4.5 (a) illustrates the Zn distribution in soil samples from the study area and shows a similar trend to Cu. High values of Zn are found in samples in a similar 1000 m diameter around the copper smelter stack. Based on the XRF results (Appendix 3), Zn values in the samples tested ranged from 69 ppm to 1217 ppm (Figure 4.6(a)), with the mean value of 358 ppm (with the exception of sample S58 at a value of about 2833 ppm because of its location in a slag dump). The enrichment factor for Zn is 5 (Table 4.3). Ellis and Kanamori

114 (1977) listed steel manufacturing as a source of Zn, whereas Crisp (1981) determined that the copper smelter was the main source of Zn in the area. There are two exceptionally high levels of Zn in samples S3 and S4 even though these samples are from places where lower values might be expected; contamination from sources other than atmospheric fallout is likely. The Zn contents in western part of the study area are also higher than for Cu and Pb; Ellis and Kanamori (1977) suggested that Zn is more volatile than Cu thus, are more likely to enter the atmosphere in fume, so when Zn is released in the form of finely divided particles, it is more likely to be dispersed farther. Kachenko and Singh (2006) observed high levels of Zn in the Port Kembla area ranging between 87 to 1947 ppm while 69% of soils were over the ecological investigation levels (200 ppm). Cartwright et al. (1976) found similar levels of Zn (2-1500 ppm) in areas surrounding a smelter plant in Port Pirie, South Australia. Both studies support the idea of significant levels of anthropogenic pollution resulting from smelters in the vicinity of sampling sites. Also like Cu, there is notable positive correlation between Zn and organic carbon indicating the retention of Zn in soils with high organic matter content such as higher Zn accumulation in topsoils (Kachenko and Singh, 2006). The geographic distribution of Pb in the study area (Figure 4.5 (b)) shows the highest concentrations of Pb within a distance of about 1000 m around the Port Kembla copper smelter stack. As can be seen from the XRF results (Appendix 3) and Figure 4.6 (b), Pb values in soils of the study area show a maximum of 506 ppm and a minimum of 12 ppm, with the average value of 115 ppm. They exceed background levels by about 5, but the western area generally contains < 50 ppm of Pb. Similar anomalies appear for Pb as they did in the Cu distribution with the highest values for sample S58 of 4157 ppm which is located in a slag dump, and samples S33 and S34 due to their proximity to the stack. The high concentration of Pb in sample S47 is due to importation of contaminated materials (probably copper slag) for construction of coastal defences above the local basalt bedrock. Figure 4.5 (b) shows that a larger part of the study area contains high values of Pb relative to Cu suggesting that the former has a more widespread and uniform distribution than the later. Relatively low levels of Pb occur in the western parts of the area as they are farthest from the effects of the Industrial Complex.

115 Again according to previous studies (Chiaradia et al., 1997; Chenhall, pers. comm., 2009) the major sources of Pb in the area are the Port Kembla Industrial Complex, including sinter plant and blast furnace of the steelworks, and urbanization since most of the samples containing higher Pb values came from the industrial part of the area and roadsides. There is one exceptionally high level of Pb in sample S24 despite its distance from the stack; this probably represents another example of contamination by slag used as fill in an area adjacent to the urban environment in Flagstaff Road. Also according to Chiaradia et al. (1997) isotopic modelling of Pb suggests that the roof dusts of the area contain Pb associated with the copper smelter, gasoline-air lead and to lesser extent -utilizing sources. The results of this study are in agreement with the study by Kachenko and Singh (2006) in the Port Kembla area and Merry and Tiller (1978) who found elevated levels of Pb at about 258 ppm in soils in the vicinity of Pb and Zn smelters at Port Pirie in South Australia. This suggests that anthropogenic pollution is associated with the smelting industries in the area. Figure 4.5 (c) depicts the distribution pattern of As in the study area. It shows a similar form to Cu, Zn and Pb with significant values in samples close to the Port Kembla copper smelter stack. From the XRF results (Appendix 3) and Figure 4.6 (c), the As values in soil samples ranged between 27 ppm to 2 ppm with the average of 9 ppm, being elevated above background values by a factor of 8. The exceptions are for sample S58 due to its location in slag dump and sample S47 which is probably related to imported slag lying above the basalt. As suggested in Jones et al. (2001), arsenic, antimony and gold are considered as elements with specific association with copper smelting operations while minimal traces of these elements are related to other industrial activities within the Port Kembla area, such as steel processing and coal powered power stations. Generally, as As is present in most copper sulphide ores it can be linked to copper smelting activities. Elevated levels of As were also found in the study of Kachenko and Singh (2006) at about 63 ppm for top soils indicating the anthropogenic pollution probably from the smelting operations in the area of Port Kembla. In earlier times, as today, most As was a byproduct of mining of other metals and is emitted into the air during extractive metallurgical processing of non-ferrous metals. Since early in

116 the 20th century, As compounds have been used as herbicides, pesticides, wood preservatives, animal feed additives, corrosion inhibitors, semi-conductors and metal alloys. Global industrial-age anthropogenic As sources are in following order: As mining production > As generated from coal > As generated from petroleum while the potential industrial-age anthropogenic As input in arable surface soils in 2000 was 2.18 ppm which is 1.2 times greater than the concentration of this element in the lithosphere (Han et al., 2003). According to Martley et al. (2004), As and Cu concentrations in soils are probably related to the concentrations in parent rock.

Tin and Selenium distribution: Figure 4.7 (a) presents the geographic distribution of Sn in the study area. Higher values are concentrated in samples close to the copper smelter stack. With the exception of samples S58 (located in a slag dump) and S47 contaminated by imported slag lying above the basalt). Tin values ranged between 28 ppm and 4 ppm, with an average of 11 ppm with the mean enrichment factor of 3 (Figure 4.8 (a) and Table 4.3). Se distribution in soil samples also shows higher concentrations close to the copper smelter stack (Figure 4.7 (b)) with low values in the western part of the study area. Maximum and minimum values of Se were 4 ppm and 0.6 ppm, respectively, with the mean enrichment factor of 4 (Figure 4.8 (b)). The highest concentrations of Sn and Se are noted around the smelter illustrating the importance of atmospheric fallout of dusts or emissions from the chimney stack as the major mechanism of pollutant dispersal through the region, with small amounts scattered away from the smelter.

Vanadium and Chromium distribution: The distribution of V in the study area (Figure 4.9 (a)) shows a different trend from other elements with higher values observed in samples in the western parts of the area. Values ranged between 15 to 267 ppm with an average of 150 ppm, showing a notable increase getting farther from the stack (Figure 4.10). Figure 4.9 (b) depicts the geographic distribution of Cr in soil samples of the area showing a similar trend to V, but the distribution pattern of this metal is less uniform than for V. The

117 maximum and minimum values of Cr are 128 and 5 ppm, respectively, with an average of 58 ppm (Figure 4.11 (b)). Samples S3 and S6 have been omitted from Figure 4.11 (a) because they show anomalies related to steelworks in the area. The amounts of silt and clay in the soil increase away from the stack (Figure 5.1); it is possible that samples with higher proportions of kaolinite, illite and smectite contain higher concentrations of metals such as V and Cr, indicating the greater capacity of clay-rich weathered sediments for metal adsorption (Liaghati et al., 2003). According to Manta et al. (2002), concentrations of some trace metals like Cr, V and Mn seem to be mainly controlled by lithogenic inputs rather than anthropogenic ones while V can also be derived from the oil refinery processes (not present in the Port Kembla area) or from domestic heating and automotive traffic (Soldi et al., 1996; Nadal et al., 2004).

Soils Soils

70 35 y = 0.0023x + 3.3399 2 60 30 R = 0.2133

50 25

40 20 Silt 30 Clay 15 y = 0.0064x + 26.592 2 20 R = 0.2613 10

10 5

0 0 0 500 1000 1500 2000 2500 3000 3500 4000 4500 0 500 1000 1500 2000 2500 3000 3500 4000 4500 Distance Distance

Figure 5.1: The percentage of silt and clay in soil samples.

Nickel and Cadmium distribution: According to XRF results (Appendix 3) and Figure 4.12 (a) the Ni distribution in the study area ranged between 53-1 ppm averaging 16 ppm with a mean enrichment factor of 3 . The distribution of Ni is much simpler than for Cu, Zn and Pb and similar to the trend for Cd with most of the study area containing values essentially close to the background levels (Figure 4.9 (c)). When Ni concentrations were plotted against distance from the smelter (Figure 4.12 (a)) a larger scatter was observed compared to Cd levels, although there is a slight increase on moving away from the smelter site. Cadmium contents of soil samples in the study area ranged between 65 ppm and 0.1 ppm, averaging about 12 ppm. The geographic distribution of Cd (Figure 4.9(d)) shows high 118 values for sample S58 due to its location in a slag dump. Sample S4 also shows a high value of Cd in spite of its distance from the stack; no immediate explanation is available. According to Manta et al. (2002) Cd and Ni concentrations are more likely to be inherited from parent materials rather than anthropogenic particulate matter. The weak correlations of these metals with Cu, Zn, As and Pb (Table 4.12) indicate that Ni and Cd have come from a different source, which could be natural instead of anthropogenic. Cadmium enters the environment through application of phosphate fertilizers and from waste incineration and combustion of several materials (Nadal et al., 2004). According to Manta et al. (2002) Ni, V, Cr and Mn distributions are mainly governed by lithogenic inputs while also relatively high levels of Cd could be interpreted to reflect a natural enrichment by weathering and pedogenesis processes.

5.1.2 Soil Quality: In this study the average trace metal concentrations in soil samples were assessed against the ANZECC and ARMCANZ (1992) and Dutch guidelines (Table 5.1). Based on Table 5.1, Cd and Zn mean concentrations in soil samples exceed the acceptable ranges in ANZECC guidelines, while mean Cu concentrations are significantly above both ANZECC and Dutch guidelines. This means that a work plan, including a detailed sampling and analysis plan, a health and safety plan and a community participation plan for second stage investigation program should be developed to assess the nature and extent of these contaminants, their potential for public health risk/occupational health and safety and potential environmental impact.

119 Table 5.1: Average concentrations of trace metals (ppm) in soil samples compared to ANZECC & Dutch soil quality guide lines. Element ANZECC (1992) Dutch This project This project (Background) Background Environmental Optimum Action Basalt Sediment Average Maximum Investigation As 0.2-30 20 29 55 1 2 9 27 Cd 0.04-2 3 0.8 12 - - 12 65 Cr 0.5-110 50 100 380 - - 58 581 Cu 1-190 60 36 190 130 73 324 1637 Ni 2-400 60 35 210 20 13 16 53 Pb <2-200 300 85 530 16 16 115 506 Sn 1-25 50 19 900 2 5 11 28 V 42 250 183 226 150 267 Zn 2-180 200 140 720 82 92 358 1217

5.1.3 Previous world-wide studies on soils: Table 5.2 presents the results of current and previous world-wide studies on soils in the vicinity of industrial and urban activities. Trace metal concentrations for soils in the study area have also been reported on a few previous occasions (Table 5.2). From Table 5.2 it could be concluded that concentrations of Cu, Zn, As and Pb in soils determined in this study are in reasonable agreement with previous work by Kachenko and Singh (2006). Trace metal concentrations in this study are obviously higher than the rural and pristine areas in Wollongong and Queensland and lower than areas around a copper smelter in Romania.

120 Table 5.2 Current and Previous Studies on Soils Samples (Types & Methods of Analysed Trace Sources of Reference Locations) Analysis Metals* Pollution

Soil samples, -25% HNO3 As:1458 & Pb:489 Mining & Razo et al., Mexico -AAS metallurgical 2004 activities

Soil samples in -HNO3-HCLO4 Cu: 863, Zn: 920, Copper smelter Pope et al., Romania -ICP-AES Pb: 740 Cd: 3.35 & 2005 As: 223

Soil samples of -HNO3+H2O2 Cu: 71, Ni: 8.7, Pb: 66.2 Urban activities. Chen et al., urban parks, China -AAS & Zn: 87.6 2005 ■Soil samples in -Aqua regia V:0.4-47.7, Cr:1-47, Small settlement Liaghati et Bells Creek -ICP-OES Cu:0.5-9.6, Zn:16.8- & agricultural al., 2003 catchment, 62.9, Pb:3-17.3 & land. Queensland, As:3-13.7 Australia. ■Rural area around -0.5N acetic acid Zn: 2.7, Cu: 5.3, Pb & − Beavington, Wollongong -0.02M EDTA Cd:<1 1973

Soils of industrial -0.5N acetic acid Zn:82, Cu:343, Pb:21, Port Kembla Beavington, area, Port Kembla -0.02M EDTA Cd:2.8 copper smelter 1973

Soil samples around -HNO3+HCL+ Cd:1.22, Cu:>330, Port Kembla Kachenko

Port Kembla 27.5% H2O2 Zn:471, Pb:>150, As:8.8 copper smelter & Singh, -ICP-AES 2006

Soil samples around -XRF Ni:15.9, Cd:11.7 , Port Kembla This study Port Kembla - 0.1 M HCl Cu:324, Zn:357.5, copper smelter - 0.05 M EDTA Pb:114.5, As:8.8, Se:1.5, Sn:11.4, Cr:57.7 & V:150.3 * Average concentration (ppm). ■ considered as pristine areas.

121 5.1.4 General discussion on soil samples: The sharp decrease in trace metal concentration on moving away from the smelter site is consistent with the pattern of smelter pollution fallouts in other areas like Port Pirie in South Australia (Cartwright et al., 1976). This pattern is probably due to metal deposition in the soil by fallout of larger sized particles within a relatively short distance of the smelter. As shown by Figure 4.13 (a-d) and 4.15 (a-b), natural background concentrations are reached approximately 1500 m from the smelter. The relatively rapid dispersal of contaminants in soil samples around the smelter site at Port Kembla indicates that the foremost mechanism of trace metal dispersal is atmospheric transportation and fallout of particulate matter. Some of this soil contamination may have been due to on-site handling of ore waste, spillage of concentrates and dispersion of stockpile ore dust since, until the 1970s, no environmental pollution control measures were enforced in ore handling or dust/ash suppression and this resulted in the distinct contamination directly around the smelter site. Samples S33-S38, which were collected inside the fence of the Port Kembla Primary School, contain significant amounts of Cu, Zn, Pb, Sn and Se, primary pathways for the presence of these elements at this site are direct depositions from the smelter stack, vehicle emissions, wind blown dust and runoff from the Port Kembla Primary school site only. This site is uphill from the main stack and cannot receive urban stormwater runoff (B.E. Chenhall, pers. comm., 2009). Long standing industrially-based societies are likely to continually be influenced by trace metal accumulation from contaminants, such as the Port Kembla area. The copper smelter could principally be viewed as a point source for the time of its operation followed by minor industrial sources and urban development which have led to additional contributions of pollutants to the local environment. Also non-airborne sources such as coal wash, ash, slag, municipal composts and buried refuse account for pockets of heavy metals at varying levels of concentration in the soil. This, in effect, has created some limitations with respect to identification of the sources of some contaminants like Pb. For example, roadside samples indicate high levels of some trace metal concentrations; sourced primarily from automobiles. The poor correlation between trace metals and clay contents suggests that the presence of mobile trace metals within the soil water was insignificant, while the positive correlation of

122 some metals like Cu, Zn, As and Pb with sand particles indicated that these pollutants are related to particulate matter in the area. In the present study, significant metal concentrations at a distance < 1 km from the copper smelter indicates that the presence of the tall stack (198 m) did not prevent dust from accumulating close to the smelter, although some of contaminations may predate the tall stack, and fugitive emissions from the smelter contributed a considerable amount of metals to the soils of the area. The state pollution control commission (Anon, 1986) estimated that total particulate emissions from the Port Kembla industrial complex exceeded 40,000 tons in 1986 and trace element concentrations in ceiling dusts from dwellings located close to industry lie in the ranges 0.09-6.9 %, 0.03-0.5 % and 0.01-2.8 % for Zn, Pb and Cu, respectively (Anon, 1993). Due to the length of the stack, (198 m), particulate emissions require a slight N/NE/E breeze to deposit particulate matter in soils around the area. The elevated levels of Cu, Zn, As and Pb are also suggestive of a smelter-sourced origin while other contributing sources into this area are the Port Kembla Industrial Complex, historical dumping sites of ash and slag from the smelter within the catchment, and urbanization. As indicated in Jones et al. (2001), As and Sb are elements which are specifically associated with copper smelting operations, as minimal traces to below detection limits of Sb were associated with other industrial activities like steel processing and coal powered stations within the area. The results of this study are in reasonable agreement with Beavington (1973) who concluded that fine particles blown from copper ore stockpiles contribute substantially to the high levels of Cu while most of the samples containing high Pb and Cd levels came from areas close to the industrial complex or roadsides. Also non-airborne sources, coal wash, ash, slag, municipal composts and buried refuse account for pockets of heavy metals at different levels of concentration in the soil. Some differences in the amount of some trace metals in the current results and the study by Martley et al. (2004) may be due to the amount of metals released to the atmosphere, and the sensitivity of detection of low metal contamination which depends on factors such as the presence of multiple sources of contamination, natural heterogeneity of metals in the soil, soil properties and sensitivity of detection techniques.

123 Chiardia et al. (1997), using Pb isotopes to determine the source of metals, concluded that over the last 50 years, atmospheric fallout of Pb-bearing particulate matter seem to have been the chief pathway of Pb to the lagoon and dwellings in the Illawarra region. It was considered that one natural and four anthropogenic sources contribute to the Pb burden of the area. The natural source consists of Permian rocks out cropping in the catchment area which have a 206Pb/ 204Pb of ~ 18.7. Anthropogenic sources are an old disbanded base- metal Pb smelter at Kanahooka (206Pb/ 204Pb ~ 16.2-16.3), the copper smelter (206Pb/204Pb ~ 17.9), gasoline-air derived Pb (206Pb/204Pb~ 16.4-16.5) and a coal-fired power station (206Pb/204Pb ~ 18.9). Also it is indicated that near surface sediments in the lagoon have a relatively constant 206Pb/204Pb Correlation coefficient analysis indicates that in soil and sediment samples there is a strong association between the trace metals, except for Ni and Cd, suggesting that the metals have a common though not necessarily unique origin. Almost all trace metals in the sediments show strong positive correlations with silt contents indicating trace metal accumulations are associated with a fine grain sizes. Also there is a negative correlation between distance from the smelter stack and amounts of Cu, Zn, As, Pb, Sn and Se in soils indicating the stack as a likely source of pollution in the area while positive correlation between distance, V and Cr suggests that these two elements originate from other pollution sources (e.g., possibly steelwork activities). Previous studies indicate that contamination of soils on the coastal plain, especially those close to smelters, arise primarily from the fallout or dispersal of particulate forms of Cu, Zn, As, Cd and Pb. Beyond a distance of about 15 km, the trace metals are probably dispersed as aerosols subject to washing out by rain, but potentially capable of being transported over great distances (Cartwright et al., 1976). The results from soil samples in this study are consistent with Kachenko and Singh (2006) for the amount of Cu, Zn, As and Pb, while concentrations of Cd are obviously higher in the current study. Concentrations of Cu, Zn, As and Pb in soils in the vicinity of smelters in other parts of the world are significantly higher than the results of this study (Pope et al., 2005; Razo et al., 2004) while the results of this study show notable concentrations of these metals compared to pristine and rural regions and even areas with urban activities (Beavington, 1973; Chen et al., 2005).

124 5.2 Investigations of trace metals in Coomaditchy Lagoon: As a landlocked system, Coomaditchy Lagoon (between samples S66 and S84 in the south- central part of Figure 3.1) is expected to be an ideal site to monitor long term Pb inputs into the environment. The information in this section is not based of the results of the current study, but derived from studies by Terry Rogers, Chiaradia et al. (1997) and B. E. Chenhall (pers. comm., 2009). Intuitively it would be expected that this site could receive Pb from other sources (e.g. gasoline Pb from urban stormwater discharges) but Pb from gasoline does not appear to be an important contributor to the Pb burden of the lagoon (B.E. Chenhall, pers. comm., 2009). The maximum and minimum amounts of Pb in sediments of this site are 700 and 13 ppm, respectively, with the trend showing an obvious decline at a depth of 50 cm, probably due to increased sedimentation rates or more restricted EPA controls since 1970. The pathways of Pb at this site are considered to be direct deposition from the smelter stack, runoff from surrounding land, urban storm water discharges, vehicle emissions and wind blown dusts.

Coomaditchy Lagoon

Pb(ppm) 0 200 400 600 800 0

10

20

30

40

Depth(cm) 50

60

70

80

Figure 5.2: Pb concentrations in sediments from Coomaditchy Lagoon.

5.3 Sediment samples: According to Ellis and Kanamori (1977) determination of metals in sediments is better than in water due to higher concentrations in the former, plus the sediments are much less subject to short-term variations due to effects such as lateral mixing, wind direction, flushing by rain water, etc. For the purpose of this study three vibracores were collected in

125 Griffins Bay close to the Purry Burry Point in north east of and analysed for trace metal contents and physical composition.

5.3.1 Sediment Distribution and Characteristics: Full results of the grain size analysis on sediment samples from this study are available in Appendix 2 and they are summarized in Figures 4.19-4.21. For core 1, the average percentages of sand, silt and clay were 68.4, 27.4 and 4.1, respectively, while core 2 contains sand, silt and clay percentages of 37.1%, 54.1% and 8.8%, respectively, and core 3 contains sand, silt and clay at 47.7%, 45.0% and 7.3%, respectively. Core 1 could be considered as sand dominated (sediment in which sand exceeds 50%) and, thus, reflects a relatively high energy depositional environment of marine-derived sand from the adjacent coastal barrier dune and beach systems which occur along the Windang Peninsula (Chenhall et al., 2004). On the other hand, cores 2 and 3 are mud-dominated (sediments in which the silt plus clay sized fractions composed more than 50%). Figures 4.22 (A-H) present the grain size analysis results of different parts of each core showing that sediment samples are classified as poorly to very poorly sorted, strongly fine skewed to very coarse skewed and very platykurtic to leptokurtic. Rubidium concentrations were measured to provide a geochemical control over potential sediment grain size-trace metal concentration relationships. Rubidium distribution in Lake Illawarra sediments has been found to relate directly to the content of fine silt and clay; thus it provides a significant measure of the grain size variation ability to retain trace elements by sand and mud-dominated substrates (Payne et al., 1997). Trace metals in sediments in this study exhibited an affinity for fine particles due to the exponential increase in surface area with decreasing particle size, therefore increasing the number of negatively charged particles on clay mineral surfaces available for adsorption of cations. Also under oxidizing conditions, Fe and Mn oxyhydroxide surface coatings on fine particles coprecipitate metal ions, and fine-grained organic matter can form metal organic complexes, which further tend to concentrate metals in the finer fraction of sediment (Gillis and Birch, 2006). Strong positive correlations of trace metals with silt and clay contents and negative correlations with sand particles in this study are reasonable evidence for the above processes.

126 5.3.2 Background Trace Metal Concentrations and Enrichment Factors in Sediments: Geochemical background or pre-anthropogenic trace metal concentrations need to be investigated to determine the amount of human impacts in sediments. Background sediment concentrations can be established by analysing deep core samples, surficial sediments from areas free from anthropogenic influences and using average trace-metal concentrations reported in the literature (Gillis and Birch, 2006). The average background concentrations of some typical trace metals in sediment samples from this study are compared with previous local and world-wide examples in Table 5.3.

Table 5.3: Background trace metal concentrations (ppm) in sediments. Average Background Concentrations(ppm) V Cr Ni Cu Zn As Cd Pb (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) This study (measured) 17.8 7.1 3.5 11.9 11.3 4.4 2.3 3.6 This study (normalized to 100% mud) 39.6 17.6 8.3 29.2 24.6 10.9 5.9 8.4

Lake Illawarra (Ellis & Kanamori, 1977) 38 44 15 Lake Illawarra (Payne et al., 1997) 33 68 17 Lake Illawarra (Chenhall et al., 2004) (Mud dominated) 37 84 15 18 (Sand dominated) 18-23 14-33 2-6 Lake Illawarra (Gillis & Birch, 2006) 19 87 39 Burrill Lake (Jones et al., 2003) – Sandy 28±7 25±7 12±6 Cores Macquarie Lake (Batley, 1987) 9 70 1 19

Port Jackson (Birch et al., 2000) 12 53 23 Victoria Harbour, Hong Kong (Tanner et 30 14 11 67 32 al., 2000)

127 Background concentrations for the trace metal concentrations in this study were calculated from XRF data obtained from below depths of 20 cm for core 1, 37 cm for core 2 and 25 cm for core 3 as concentrations of Cu, Zn and Pb display a distinct uniform distribution with depth thus providing the basis for determination of background (pre-industrial) values for these elements (Appendix 3). Background concentrations of Cu, Zn and Pb in Lake Illawarra sediments determined in the current study are lower than the values reported in previous studies of Lake Illawarra due to different sampling methods and sediment characteristics; however, after normalization these values are close to those of Chenhall et al. (2004) for sand dominated parts of Lake Illawarra and Jones et al. (2003) for sandy cores of Burrill Lake. Table 4.6 shows enrichment factors of some trace metals in all three cores. Based on this table, trace elements which show significant enrichment factors compared to the background values will be discussed in more detail. Sediment concentrations for As, Cd, V, Cr, Ni, Cu, Zn and Pb at representative core depths are shown in Table 5.3, with the full results contained within Appendix 3. This table indicates that the trace metal concentrations are variable not only within, but also between cores. Background concentrations and enrichment factors in sediments of this project are not consistent with other studies, and according to Murrie (1994), the greatest variability between past studies in this part of the lake could be due to lateral transport and resuspension of fines from adjacent dredging. From an environmental stand point, Zn and Pb are the most significant contaminants in core 1 as the former is enriched above background values by a factor of 6 and the latter by a factor of 3.7. Figure 4.26 (a-b) illustrates the distribution of Zn and Pb in this core. Enrichment in Zn and Pb in the upper portions of the core is related to fluctuations in grain size, since their concentrations show a relatively similar pattern to Rb (an effective proxy for grain size) concentrations. However, in sandy sediments Rb shows a greater variability, reflecting differences in the proportion of sand to silt and clay sized particles, associated with more hydrodynamically active sediment regimes. Also Figure 4.26 (a-b) shows that both Zn and Pb show considerable enrichment in the upper 15 cm of sediment with a notable decrease above a depth of about 8.5 cm probably related to introduction of the Environmental Protection Act (EPA) in 1970.

128 Lower concentrations of trace metals in core 1 compared to the other two cores could be due to the higher proportion of sand in this core. The very low Zn and Pb concentrations found in segments between 24-12 cm depth possibly indicate that this core site may be close to an old drainage channel which formerly linked Griffins Bay to the ocean near Port Kembla. In the presence of tidal scouring it is expected that low metal accumulation rates happen because of the preferential accumulation of trace metals in fine sediments (Ellis and Kanamori, 1977). When tidal scouring ceased, very rapid infilling would have occurred, as was observed west of the Windang Bridge following partial closure of the entrance channel. The different profile of Cu compared with Zn and Pb is indicative of biological fractionation or some selectivity of adsorption, or of secondary mobilization of metals by organic substances (Ellis and Kanamori, 1977). Core 2 is the most polluted core with significant concentrations of Zn showing a mean enrichment factor of 33.3 and Pb with an enrichment factor of 22.8; the highest content of silt and clay of the three cores studied. Distributions of Zn and Pb do not illustrate similar patterns to Rb concentrations; therefore, elevated levels of these metals are probably not related to variations in grain size. Other trace metals like V, Cr, Ni and Cu show notable enrichment factors compared to the background values in this core. Trace metal contamination in core 2 extends down to about 40 cm depth. A notable increase in Pb concentration at a depth of 15-12 cm could be because of leaded gasoline, since there was a reliance on cars for transport in the Illawarra region between 1930 and 1996. The 1970s EPA effects on Zn concentrations of this core could be observed above a depth of 9.5 cm which could reflect higher sedimentation rates in this core compared to core 1. In core 3 notable concentrations of Zn and Pb were also observed with enrichment factors of 20.4 and 12.4, respectively, while V, Cr, Ni and Cu are elevated above background values by about 4 to 7 times. Trace metal contamination could be observed in this core down to the depth of 40 cm. Percentages of silt and clay-sized fractions in this core is more than in core 1 but less than core 2. This is reflected by the trace metal distributions in the cores. Copper is the most evenly dispersed element in the cores, with the Cu distribution showing relatively similar pattern to the Rb concentrations. Also based on Table 4.6, which reveals enriched sediment metal concentrations for all three cores, enrichment factors of trace

129 metals in core 1 are somewhat lower than those in the other two cores which could be a function of disturbance of this site. Enrichment factors of Cu, Zn and Pb in core 1 are consistent with studies by Chenhall et al. (1994) and Payne et al. (1997). Trace metal enrichment factors of Cu and Pb in core 3 are close to those of Roy and Peat (1974) while trace metal enrichment factors in core 2 are significantly higher than those of previous studies on the lake. Trace metal enrichment factors for Co, Sb, Cr and As are in agreement with the study by Chenhall et al. (2004). Generally the significant decline in concentration of metals in segments above 8-10 cm depth is possibly equated with decreasing levels of sediment contamination as a consequence of more stringent industrial pollution control measures introduced in the 1970s. The depth to which trace metal contamination extends in Lake Illawarra is site specific because of different rates of sediment accretion as well as other factors like sediment burrowing benthic organisms and geochemically mediated processes (Chenhall et al., 1995). All trace metals display a relatively systematic distribution with respect to sediment grain size with the greater concentrations present in the muddy sediments of the lake in cores 2 and 3. Concentration maxima of Cu (≥ 100 ppm), Zn (> 300 ppm) and Pb (≥ 50 ppm) in cores 2 and 3 in this study are in good agreement with Chenhall et al. (2004), but because of significant differences in the background values, enrichment factors of trace metals in this study are obviously higher than previous studies. Comparing the trend of Pb concentrations in sediment samples in this study to samples from Coomaditchy Lagoon (Figure 5.2; B.E. Chenhall, pers. comm., 2009), shows that the maximum concentration of Pb is 255 ppm at the depth of 14 cm in core 2 of this study while samples from Coomaditchy Lagoon show a maximum value of Pb at about 700 ppm at a depth of 45 cm. Thus, it can be concluded that the amounts of Pb pollution in Lake Illawarra are significantly lower those in Coomaditchy Lagoon due to higher amounts of metal dilution by clastic sediment in the lake and the enclosed run-off system at Coomaditchy Lagoon.

5.3.3 Sediment Quality: According to Chenhall et al. (2004), sediments in Lake Illawarra generally have low (< 2.5) enrichment factors for Cu, Zn and Pb suggesting that the maximum concentrations of these metals have accumulated in the upper 20 cm of sediments. A noticeable exception

130 is sediments from southern Griffins Bay where higher enrichment factors characterize the sediment and reflect the proximity of this site to the Port Kembla Industrial Complex. In this study, average industrially-contaminated trace metal data from Griffins Bay were assessed against the ANZECC & ARMCANZ (2000) sediment quality guidelines (Table 5.4).

Table 5.4: Average concentrations of trace metals (ppm) in upper sediments in Lake Illawarra compared to the ANZECC & ARMCANZ (2000) Sediment Quality Guidelines. ANZEC & ARMCANZ 2000 Element Core 1 Core 2 Core 3 ISQG-Low ISQG-High (ppm) (20 cm) (37 cm) (25 cm) V 7.0 89.3 78.0 Cr 1.7 28.5 22.7 80 370 Ni 4.0 26.2 24.1 21 52 Cu 15.8 88.0 68.4 65 270 Zn 68.1 375.0 229.7 200 410 As 4.8 12.4 10.4 20 70 Cd 1.8 5.6 5.8 1.5 10 Pb 13.4 81.5 44.2 50 220

Based on Table 5.4, sediments from this part of the lake do not exceed the high trigger value (ISQG-high). In core 1, the average concentrations of elements are obviously below the low trigger value (ISQG-low). In core 2, these values are between the low and high trigger values except for Cr and As which are below ISQG-low and core 3 shows the same pattern as core 2 except for Pb values which are below the ISQG-low trigger. In all three cores, As concentrations are low and never exceed the low trigger values, while Cd concentrations observed are between two trigger values. Based on the ANZECC (2000) Sediment and Water Quality Guideline decision tree (Figure 2.2), sediments with trace metal concentrations below low trigger values are considered as low risk while trace metal accumulations between the low and high trigger values require further investigation. Since concentrations of trace metals between the trigger values are above background levels, concentrations in these samples require further investigation of

131 the factors controlling bioavailability. These factors are acid volatile sulphide (AVS), pore water concentrations, sediment speciation and organic carbon. According to ANZECC/ARMCANZ (2000) guidelines adverse biological effects are occasionally observed between low and high guideline values.

5.3.4 Previous and current work: Estuarine sediments in urban areas are often found to be contaminated with trace metals which are derived from variety of sources including: waste dumps or sewage overflows, motor vehicle traffic and also industries, especially mining or smelting (Rate et al., 2000). In this regard, trace metal concentrations in Lake Illawarra sediments have been the subject of a number of previous studies. The important information concerning these studies, together with methodologies utilized in the current and previous studies are summarized in Table 5.5.

According to Murrie (1994), Griffins Bay exhibits elevated sediment metal concentrations well above normal Lake Illawarra sediments and those from other estuaries, such as Burrill Lake and Bells Creek catchment which are pristine or have much less anthropogenically impacted catchments. Trace metal concentrations from this study are obviously lower than those of Lake Macquarie, NSW; Spencer Gulf, South Australia; Derwent River, Tasmania; and Deule-canal sediments in France which are considered as highly polluted lagoonal systems. The important information in the current and previous world-wide studies on estuarine samples is summarized in Table 5.6. This table shows that metal contamination in estuarine sediments often reflects the proximity to industry pollutant inputs.

5.3.5 Estimation of Sedimentation Rates: Sedimentation rates in Lake Illawarra prior to European development were estimated by radiocarbon dating methods on shells (Notospisula trigonella) preserved in the sediment, the limitations attached to this dating technique include its limited applicability to sediments less than 200 years in age and the potential for erroneous 14C ages if older carbon, in the form of reworked, redeposited shells are incorporated in the sediment

132 (Chenhall et al., 1995). Alternatively, the chronology of sediments deposited in the last 120 years can be determined by construction and modelling of 210Pb (Smith, 1982) and 137Cs (Loughran and Campbell, 1983) depth-decay curves. These methods are also not without their limitations, including availability of facilities, costing, and in the southern hemisphere, the very small quantity of 137Cs in the samples. Another important consideration in evaluating 137Cs profiles is the potential mobility of this element (displacement of 137Cs by Na and Ca) in the sediment column of saline environments (Heaton, 1982). Furthermore, sediment age-depth profiles using 210Pb data may not coincide with profiles generated by site-specific markers such as trace metals (Kilby and Batley, 1993). Ash and trace metal profiles were considered as useful methods to estimate sedimentation rates in the Lake Illawarra in previous studies, although the results of a trial (Chenhall et al., 1995) were somewhat disappointing based on the reasons below: ƒ Potential trace metal mobility; ƒ Biogenic and physical disturbance of the sediment; and ƒ Uncertainties about the dates of introduction of trace metals into the sediment profiles depending on selection of 1910 (Southern Copper) or 1928 (BHP Steel).

Thus, sites far from known point sources could not be assessed accurately by trace metal profiling mainly due to uncertainties in the dates of introduction of trace metals from diverse sources (Payne et al., 1997). Sedimentation rates in this study were facilitated using amino acid racemisation techniques (Sloss et al., 2004) on Notospisula trigonella valves, and yielded rates of 0.39 mm/year in core 1, 0.78-0.43 mm/year for core 2 and 0.29-0.42 mm/year for core 3 (Table 4.7 and full results refer to Appendix 4). If these results could be considered as pre-industrial sediment accumulation, it is concluded that they are in good agreement with previous studies on the lake (Chenhall et al., 1995, 2001; Sloss et al., 2004). Also it could be observed from section 4.3.3 that significant contaminants like Zn and Pb extend to the depth of 14 cm in core 1, 35 cm in core 2 and 26 cm in core 3.

133 Table 5.5: Previous and current works on Lake Illawarra. Sample Acquisition Method of Analysis Metals Analysed Enrichment factor Sedimentation References Rates

3 box cores 40-45 cm -AAS and Cu, Pb, Zn, Ni, Cu: 4, Zn: 34, 1.4 mm/year Roy & Peat in length Colorimetry of 150 Co, Mo & As Pb: 11 (1974) µm sediment fraction 2 deep cores, 5 short AAS of -75 µm Cu, Cd, Pb, Zn & Zn: >10, Cu: 10, 2.3-3.1 mm/year Ellis & cores, 13 dredged sediment fraction Fe Pb: Kanamori samples - Trace metal (1977) profiles 8 cores from deep -XRF Zn, Cu, Pb, Fe, Zn:5.9, Pb:3.5, 6.9-8.8 mm/year Chenhall et parts of the lake. -ICPMS Cd & Mn Cu:1.8 al. (1994) - Ash profiles 60-70 cm cores -XRF Cu, Zn & Pb Zn:5.9, Pb:3.5, 3.7-5.2 (1019) Payne et al. Cu:1.8 4.3-6.2 (1928) (1997) mm/year Cores 60-70cm in -Payne et al. (1997) Cu, Zn & Pb Pb&Cd≤6, 3-5 mm/year Chenhall et length Chenhall et al. Cu:3-6 al. (2001) -8m vibracore (1994). and XRF of -63µm Cu, Pb, Zn, Cr, Chenhall et sediment As, Sb & Co al. (2004) -NAA of -63µm sediment

120 surficial (<2cm) -aqua regia Cd, Cu, Pb & Zn Zn≥3, Pb&Cd≤6, Gillis & sediment samples -ICP-AES Cu:3-6 Birch (2006) -30 creek samples -4 sed. Cores 20-50cm

3 vibracores 150cm in -XRF V, Cr, Ni, Cu, Zn, Core1: Zn:6, Pb:3.7 This project length As, Se, Sr, Cd, Sn Core2: Cu:7.4, & Pb Zn:33.3, Pb:22.8, V, Cr & Ni>4 As, Cd>2 Core3: Cu:5.7, Zn:20.4, Pb:12.4, V& Ni>4 Cr, Cd & As>2

134 Table 5.6: Other estuarine metal investigations. Metal Concentrations (ppm) in Sediments From Various Sources

Location Cu Zn Pb Cd V Cr As Sources Reference Spencer Gulf, 3-122 11- 2-5270 0.5-    Lead smelter Ward & SA 16667 267 Young, 1981 Lake 156 1160 600 42    Lead-zinc smelter. Batley, 1987 Macquarie, NSW Parramatta 90 983 233     Industrialization & Birch et al, River urbanization. 2000 catchment, NSW Swan River 30.4  47.1 0.32    Industrialization & Rate et al., Estuary, WA urbanization. 2000 Derwent <50- <200- <50-    <20- Pasminco Hobart Jones et al., Estuary, 2000 >12000 >2400 >200 zinc refinery. 2003 Tasmania ♦Burrill Lake, 32±24 29±23 13±9     Agricultural Jones et al., NSW activities. 2003 ♦Bells Creek 0.5-5.8 18.2-68 3-7.3  2.2- 1- 3- Small settlement & Liaghati et catchment 3 26 10.8 agricultural land. al., 2003

Tamar River 40-918 114-714 31-460 Industrial practices/ Armstrong, estuary/ mining activities. 2005 Tasmania Outer Apra >20 >100 >30   >8 >4 Commercial & Denton et al., Harbour military port. 2005 (Guam) Deule-canal 149- 27- 1.2-    Lead & zinc smelter Boughriet et Sediments 12895 10079 1399 al., 2006 (France) Lake Illawarra Port Kembla This study Industrial Complex Core 1 12.4 26.1 6.1 1.8 10.9 12.6 4.6 Core 2 57.1 214.3 51.0 4.4 64.5 16.8 9.2 Core 3 28.9 78.5 16.2 4.3 39.1 8.1 6.0 ♦Considered as pristine areas

135 Thus, depending on the trace metal profiles in this study, sedimentation rates since industrialisation for core 1, 2 and 3 would be about 1.4 mm, 3.5 mm and 2.6 mm per year, respectively, which are consistent with the findings of Roy and Peat (1974) and Ellis and Kanamori (1977). The sedimentation rate of core 1 is similar to Burrill Lake which has been estimated at about 1.7 mm/year (Jones et al., 2003). According to Chenhall et al. (2004) the depth to which trace metal contamination extends in Lake Illawarra is site specific, possibly controlled by the rate of sediment accretion as well as other factors such as sediment burrowing by benthic organisms and geochemically mediated processes. A strong metals gradient in the northern part of the lake adjacent to the entrance of Griffins Bay probably originates from dispersion of contaminated sediments from that embayment. Sediment resuspension in Griffins Bay occurs during strong wind conditions and northeast winds may result in an exchange of water between Griffins Bay and the main body of the lake. Strong southerly and westerly winds in summer and winter, respectively, would probably confine resuspended material within Griffins Bay due to the orientation of the embayment in the northeast corner of the Lake (Clarke & Eliot, 1984). Comparing the metal concentration profiles in Lake Illawarra sediments (current study) with samples from Coomaditchy Lagoon in Figure 5.2 (B.E. Chenhall, pers. comm., 2009), it can be observed that sedimentation rates in Coomaditchy Lagoon are significantly higher than in Lake Illawarra since the trend of Pb concentrations in the Coomaditchy samples shows an obvious decline at a depth of 50 cm while the highest concentrations of this element in Lake Illawarra cores are at depths of about 15 cm. The reason for this is the higher amounts of sediment runoff into this enclosed lagoon from the surrounding urban development.

5.3.6 Anthropogenic Trace-Metal Loading and Retention in Lake Illawarra: A statistical evaluation of the more significant relationships between some of the measured variables is provided in Table 4.13 These data are interpreted below: ƒ positive strong (r > 0.5) correlations between almost all trace metals suggest that the trace elements have a common, though not necessarily unique origin and mode of occurrence;

136 ƒ significant positive correlations of metal concentrations with mud content and the negative correlation with sand content both reflect the role of finely-divided materials in retaining metals by surface reaction mechanisms and the low trace element content of quartz sand; and ƒ the strong negative correlation between Rb and sand % reflects the (illitic) clay contents of the sediments and underpins the potential for use of conservative elements (naturally-occurring Rb, not introduced by anthropogenic activities) as monitors of grain size-related variations in trace metal abundances.

5.3.7 Sources of Trace Metals in Lake Illawarra: Although trace metals derived from different sources, for instance, Zn from galvanized iron, Pb from the combustion of petrol-Pb additives, and trace metals associated with domestic effluents (Wittman, 1981), can contribute to trace metal loading in estuarine systems, potentially a prime source of trace metals in Lake Illawarra is the Port Kembla Industrial Complex located near the north-eastern margin of the lake. The modes of delivery of trace metals to the lake from industries are probably diverse and could include dispersal of industrially-derived trace metal-bearing ash (Payne et al., 1997) and the erosion, transportation and deposition by wind and water of contaminated soils near major industrial sites, and also dissolved metals which could accumulate in sediments via surface and groundwater flows. According to Chenhall et al. (2004), ash uniquely sourced from steel manufacture, copper smelting and electric power generation is present in the lake sediments and a direct link between ash and dusts of industrial origin and metals including Cu, Pb, Zn and the metalloid As, can be observed. Chromium concentrations in pre- European sediments most likely reflect the relative abundance of basaltic rocks (Dapto Latite), volcanogenic sediments and their weathered equivalents around the lake periphery (Chenhall et al., 2004). Concentrations of trace metals like Zn, Cu, Cd and Pb in sediments of Griffins Bay, which is located in close proximity to the Port Kembla Industrial Complex, are obviously higher than in the rest of the lake, indicating the industrial complex as an important source of trace metals into the system (Roy & Peat 1975; Payne et al., 1997, Chenhall et al., 2004; Gillis & Birch, 2006). Major industries in Port Kembla include the Port Kembla copper smelter

137 (decommissioned in 2003), a smelting and refining plant and a large integrated steel works facility. Also numerous minor industries are associated with the complex. Fine particulate matter from Port Kembla is deposited directly onto the lake and surrounding catchment under certain wind directions (Gillis & Birch, 2006). Furthermore, a number of creeks draining sub-catchments associated with urban areas adjacent to the Port Kembla may be considered as another source of trace metals from the industrial complex. Trace metals, such as Zn, Cu, Cd and Pb, are common constituents of urban storm water runoff from vehicle wear and exhaust emissions, corrosion of plumbing, roofs, etc. (Sutherland, 2000; Gillis and Birch, 2006). Because water exchange between Griffins Bay and the main body of the lake is usually limited by a subaqueous spit, Griffins Bay acts as a sink for sediments and associated trace metals entering the embayment (Clarke & Eliot, 1984). Also according to Gillis and Birch (2006), the particularly high normalized trace metal concentrations in Griffins Bay sediments compared to the rest of Lake Illawarra indicate that direct atmospheric deposition is not the main mechanism governing trace metal distribution in the lake. If it was, normalized metal concentrations would be expected to show a strong northeast-southwest gradient across the lake, which is not evident in their study. Thus, inputs from creeks in the northeast parts of the lake seem to be more important in determining spatial patterns than atmospheric processes. In addition, Warrawong hospital is another potential source of trace metals drained to this part of the lake (Smith, 2001). Based on previous studies (Boughreit et al., 2007; Rate et al., 2000) it could be concluded that sites close to industrial sources are more contaminated than those with lower proximities to these sources of pollution.

5.4 Trace Metal Bioavailability: Beside natural processes, soils can be polluted by metals released into the environment from various sources. These elements are likely to be bioaccumulated in plants and animals, finally making their ways into the human food chain. Ingestion, inhalation and skin contact have been found as important routes of human exposure to soil metals. Considering the fact that soils and vegetation are the major sinks for airborne metals, the estimation of metal levels in these media is a useful way to establish trends in abundance

138 and their consequences as a result of natural and anthropogenic changes (Nadal et al., 2004). Dilute HCl and EDTA extractants are commonly used as indicators of trace-metal bioavailability in aquatic sediments (Batley, 1987; Ying et al., 1992; Birch et al., 2000; Carballeira et al., 2000). Dilute HCl removes loosely bonded and adsorbed metal precipitated salts, without any significant attack on the detrital lattice (Bradshaw et al., 1974; Agemian & Chau, 1977; Sutherland et al., 2001) and has been used to simulate the effect of gastric juices in the gut of a detritus feeder (Waldichuk, 1985). EDTA releases adsorbed, precipitated and complexed metals (Chester & Voutsinou, 1981; Ying et al., 1992). Based on the full XRF results for trace metal extractions by HCl and EDTA and quality controls (Appendix 5) extracted trace metals in group 1 of Table 4.10 including V, Cr, Mn, Cu, Zn, Sr and Pb demonstrated fairly reliable values so they are discussed more fully in the current study.

5.4.1 Extracted Metals Distribution Copper, Zinc and Lead distribution: The geographic distributions of extractable amounts of Cu, Zn and Pb in soil samples are shown in Figure 4.32 (a-f) for both HCl and EDTA tests. They indicate that significant extractable amounts of these metals have been found in samples close to the main chimney of the Port Kemble copper smelter. Therefore, Figure 4.33 (a-c) compares the total concentrations of these metals to the extractable values in both experiments based on the distance from the stack. Again, like for other XRF figures samples S33, S34 and S58 have been omitted from the graphs due to anomalies. The average value of Cu in the HCl test is 95 ppm, and in EDTA is 116 ppm (Figure 4.33 a) while the average total amount of this metal is 324 ppm which means that about 22 % and 32 % of this metal are extractable by HCl and EDTA, respectively. Therefore, in the case of Cu, EDTA could extract higher amounts of metals than HCl. In both tests, sample S45 shows notable amounts of extractable Cu due to its location (Appendix 1). The average total concentration of Zn is around 358 ppm while the average values of extracted metal are about 143 and 117 ppm in HCl and EDTA experiments, respectively,

139 showing 42 % and 33 % of Zn are extractable by HCl and EDTA, respectively (Figure 4.33 b). So, in the case of Zn, HCl could extract higher amounts of metal than the EDTA. In regards to XRF results and geographic distributions of Zn, it could be concluded that the amounts of extractable metal in western parts of the study area show higher values than for Cu and Pb as Zn is more volatile and likely to enter the atmosphere in fumes, therefore it could be dispersed over greater distances (Ellis and Kanamori, 1977). The average total amount of Pb is 115 ppm in soil samples, HCl could extract 29 ppm which is about 28 % and EDTA extracts 41 ppm that is around 37 % of the total values of this metal (Figure 4.33 (c)). Samples S24, S38, S45, S50 and S76 show anomalies in Figure 4.33 (c) due to locations on roadsides. A large part of the study area contains higher values of Pb compared to Cu indicating that the former has a more widespread and uniform distribution than the latter. In all the above cases, obvious negative correlations between the extractable amounts of these metals and the distance from the stack suggest that the industrial activities are the main source of metal pollution in the area. According to previous studies (Beavington, 1975; Martley et al., 2004; Kachenko & Singh, 2006) the Port Kembla Industrial Complex comprises of sinter plant and blast furnace of the steelworks, copper smelting works and other industries in addition to the minor contribution of coal-utilizing sources and urbanisation are the main sources of total and extractable amounts of Cu, Zn and Pb in the study area. According to Kachenko and Singh (2006) accumulation of Cu in vegetables from Port Kembla was considerably higher than other industrial areas in New South Wales (like Boolaroo) and pristine areas (like Cowra). This is in agreement with Beavington (1975), emphasizing the role of the copper smelter as an important source of Cu and other trace metals in the region.

Chromium distribution: Based on Figures 4.34 (a-b) concentrations of extracted Cr in both experiments show a relatively uniform distribution within the study area. Based on the XRF results (Appendix 5), while total concentrations of Cr ranged between 5.0 to 128 ppm and increase sharply farther from the smelter stack, extractable amounts of this metal in both experiments show a very slight decline with distance (Figure 4.35(b)). The average

140 extraction percentage of Cr, at about 47-49 % decreases on moving farther from the stack indicating that high Cr concentrations in the western parts of the study area, which are possibly related to the steelworks, are in the form of solid particulate materials thus they are not readily extractable.

Vanadium, Manganese and Strontium distribution: Figure 4.36 (a-f) depicts the geographic distribution of the extractable amounts of V, Mn and Sr, respectively. Like the total amounts of these metals, extractable values increase on moving farther from the copper smelter stack (Figure 4.37 (a-c); however, except for Mn, the percentage of extractable metals in this group decreases with increasing distance. Figure 4.36 (a and b) shows the geographic distribution of extractable V in both experiments and it can be concluded that significant extractable amounts of this metal are concentrated in western parts of the study area. Figure 4.37 (a) shows that HCl extracted an average of 15 ppm V whereas EDTA extracted around 12 ppm. Since the average total amount of this metal is about 150 ppm only about 10-14 % of V is extractable in both experiments. Western parts of the study area show notable concentrations of Mn. XRF results in Appendix 5 suggest that the average extractable amounts of Mn are 234 and 135 ppm in HCl and EDTA tests, respectively. Since the average total amount of Mn is about 1000 ppm, it indicates that 24 % and 14% of this element are extractable in HCl and EDTA experiments, respectively and as showing an increase within the distance form the copper smelter stack, it is not related to industrial activities in the area. Geographic distributions of Sr are presented in Figures 4.36 (e and f) for the HCl and EDTA experiments, respectively, while the pattern of distribution of this metal is like those for V and Mn (i.e., higher concentrations in the western parts of the area) it seems that Sr is distributed more uniformly than V and Mn. XRF results show that the average amount of Sr in HCl test is about 24 ppm and in EDTA is around 14 ppm while the total average of this metal is 283 ppm. Therefore, around 14 % and 7 % of Sr (Table 4.11) could be extracted by HCl and EDTA, respectively, and as these percentage values decrease slightly with distance they could be related to industrial activities in the area.

141 Generally based on positive correlations of these metals to the distance from the Port Kembla copper smelter stack, one could conclude that all these three metals show significant extracted amounts in western parts of the area. One reason could be the high affinity of carbonates and silt and clay-sized particles to these metals. However as the percentage of extractable V and Sr decline with increasing distance from the copper smelter stack, it could be suggested that the percentage amounts of extractable metals may be also related to industrial activities in the region.

5.4.2 Soil-Plant Transfer Coefficient: The transfer coefficient (Kloke et al., 1984) distinguishes the relative differences in bioavailability of metals to plants and is a function of both soil and plant properties.

T.C = concentration of a metal in vegetable crop (DW) total metal concentration in the soil

Higher transfer coefficients reflect relatively poor retention of metals in soils or greater efficiency of plants to absorb metals, while low coefficients reflect the strong sorption of metals to the soil colloids (Alloway & Ayres, 1997) or the inclusion of metals in solid dust particles. The results from Kachenko and Singh (2006) are useful in estimating the amount of trace metal concentrations in vegetables of the study area because, according to literature, the concentration of trace metals in vegetables depends on various factors like soil properties, types of pollution sources and vegetable types. Therefore, based on the results of Kachenko and Singh (2006) for trace metal concentrations in vegetables growing in Port Kembla area, Table 5.7 illustrates the range of transfer coefficients for Cu, Zn and Pb in current study. This table also outlines a range of generalized transfer coefficients which have been suggested by Alloway & Ayres (1997). Kloke’s transfer coefficients (Kloke et al., 1984) are based on the root uptake of metals, with no consideration given to aerial deposition and foliar adsorption of elements.

142 Table 5.7: The range of transfer coefficients of metals and their suggested coefficient range. Vegetablesa Leek Lettuce Parsley Spinach Suggested Rangeb

Trace metals Cu 0.01 0.01 0.01 0.02 0.01-0.1 Zn 0.03 0.04 0.05 0.03 1-10 Pb 0.004 0.002 0.002 0.001 0.01-0.1 Values are in ppm fresh weight (FW). a: Kachenko and Singh (2006). b: Kloke et al. (1984).

Based on results from Kachenko and Singh (2006) it could be concluded that, at Port Kembla, high concentrations of Cu in the top soil may result in greater vegetable intake while aerial metal deposits may have further contributed to vegetable Cu concentrations resulting in higher transfer coefficients. These results (Kachenko and Singh, 2006) demonstrate that there is relatively high soil-plant transfer of Cu and Pb to leafy vegetables in the area where there is evidence of significant anthropogenic metal contamination.

5.4.3 Previous Local and World Wide Studies: Some important information on trace metal extractability in soils and vegetable types from previous local and world-wide studies are summarized in Tables 5.8 to 5.11.

5.4.4 General discussion on trace metal bioavailability: Significant levels of extractable Cu, Zn and Pb in samples located close to the Port Kembla copper smelter stack, strong positive correlations between these metals and negative correlations with the distance from the stack appear as a result of anthropogenic activities in the region. In agreement with previous studies (Cartwright et al., 1976; Beavington, 1975), it can be suggested that the concentrations of extractable trace metals like Cu, Zn and Pb declined exponentially with distance from the smelter.

143 Table 5.8 Trace metals in soils and leafy vegetables in the Wollongong area Samples Methods Analysed Extractable Uptake by Sources Reference (Types & of Trace Trace Vegetables of Locations) Analysis Metals Metals in (ppm) Pollution soil (ppm)

Soils & leafy -6N nitric Cu, Zn, Cu: 847 Cu: ◊ 64, ⌂ Port Beavington, vegetables in acid Pb, Cd, Zn: 229 55 & ₪16.5 Kembla 1975 Wollongong, -0.5N Ni & Fe Pb: 13.3 Zn: ◊ 316, Copper Australia acetic Cd: 1.99 ⌂ 227 & Smelter acid Ni: 1.05 ₪60 -0.02M Fe: NA Pb: ◊ 23, ⌂ EDTA 10.3 & -AAS ₪1.0 Cd: ◊ 4.5, ⌂ 1.16 & ₪0.63 Ni: ◊ 2.7, ⌂ 5.0 & ₪ 0.9 Fe: ◊ 593, ⌂ 226 & ₪ 60 Highlights: Significant correlations observed between distance from the main chimney of the smelter and the amounts of metals in both soil & leaf vegetables (lettuce). Also notable correlations occur among the levels of most heavy metals in both soil & leaf vegetables.

◊ Lettuce, ⌂ Other leaf vegetables, ₪ Chilies.

144 Table 5.9 Trace metals in soils and vegetables in eastern NSW Samples Methods Analysed Extractable Uptake by Sources Reference (Types & of Trace Trace Vegetables of Locations) Analysis Metals Metals in (ppm) Pollution soil (ppm) -Samples of -USEPA As, Cd,  In PK: -Zinc & Kachenko soils & 3050B Pb, Zn Cu:‼3.24, lead & Singh, vegetables in -ICP-AES &Cu ◊1.96,♣2.27 & mines. 2006 NSW -HNO3+ ◘6.87 -Copper (Boolaroo, Port HClO4 Pb: :‼0.484, smelter. Kembla, ◊0.176,♣0.256 Cowra & & ◘0.125 Sydney Basin) Zn: ‼10.73, -Boolaroo and Port Kembla are considered as polluted by ◊15.71,♣17.91 smelting industries, Sydney Basin by manufacturing & ◘11.07 industries, sewage sludge and other waste waters and In Cowra: Cowra could be considered as relatively pristine area. Cu: ‼0.925, -Order uptake of Zn in PK: ◊0.356,♣0.370 Parsley>Spinach>Leek>Rhubarb>Cabbage>Lettuce. & ◘0.638 -The concentration of Zn in the vegetables sampled Pb: ‼<0.02, across all regions was strongly correlated with soil Zn ◊<0.02,♣0.621 content. & ◘0.202 -Cu levels were highest in PK with greatest Zn: 3.55, concentration in spinach. 2.97,♣3.21 &

◘2.76

† Cabbage, ‡ Carrot, ‼ Leek, ◊ Lettuce, ● Endive,

◘Spinach, ○Onion, ♠Cauliflower, ♦Celery, ■ Beetroot,

◄ Rhubarb, ♣ Parsley, ♥ Mint.

Highlights: Partitioning of Pb is greater in roots than leafy vegetables. The potential accumulation of heavy metals in vegetables grown in the vicinity of smelters is greater than other areas indicating the fact that cultivation of leafy vegetables in smelting areas should be avoided.

145 Table 5.10 Trace metals in soils and leafy vegetables in northern Greece Samples (Types Methods Analysed Uptake by Sources of Reference & Locations) of Analysis Trace Vegetables (ppm) Pollution Metals

Alluvial sandy HNO3. Pb:24.2 Pb: †0.57, ‡0.37, Industrial Voutsa et loams, silty loams INAA & Zn:68.3 ‼0.63, ◊11.2, ●1.52 area of al. (1996) and vegetables. AAS. Cr:98.7 Zn: †64, ‡21.1, Thessa- Mn:443 ‼21.2, ◊39.2, ●24.6 loniki, (ppm) Cr: †2.38, ‡0.47, northern ‼0.30, ◊1.34, ●1.41 Greece. Mn: †19.5, ‡3.47, ‼4.10, ◊33.3, ●62 † Cabbage, ‡ Carrot, ‼ Leek, ◊ Lettuce, ● Endive, ◘Spinach, ○Onion, ♠Cauliflower, ♦Celery, ■ Beetroot, ◄ Rhubarb, ♣ Parsley, ♥ Mint.

Table 5.11 Trace metals in soils around Port Pirie, South Australia Samples (Types Methods of Analysed Extractable Sources of Reference & Locations) Analysis Trace Trace Metals in Pollution Metals soil (ppm)

Surface soils at -0.1M Pb, Zn, Cd Pb>100, Zn>40, Lead Cartwright et Port Pirie, South EDTA & Cu Cd>1& smelter al., 1976 Australia -AAS Cu:6-10

Highlights: Contamination declined significantly with distance from the smelter, but was detectable up to 40-65 km from the source depending upon direction. Over short distances soil contamination resulted from the fallout of particulate emissions of variable composition, but over 15 km the heavy metals are probably dispersed mainly as aerosols. Since the local soils are highly alkaline, there has been negligible leaching of these metals from the surface soil and their availability to plants is low.

Higher levels of extracted metals could be observed in soil and vegetable samples located in the vicinity of Port Kembla and Port Pirie smelters compared to pristine areas (like Cowra) (Cartwright et al., 1976; Kachenko & Singh, 2006). Also, as could be concluded

146 from the results of current and previous studies, soil contamination is partly due to redispersal of dust from exposed piles of ore concentrations, slag heaps and the more polluted soils (Cartwright et al., 1976). According to the literature, elevated levels of trace metals in soils may lead to uptake by plants, since the primary pathway for most trace metals to vegetable roots are through the soil. In contrast, atmospheric particulate matter is considered as the main pathway of trace elements to vegetables leaves; however, there is no generally accepted relationship between the concentrations of metals in soils and plants due to many different factors like soil metal bioavailability, plant growth, metal distribution to plant parts and soil properties (Fytianos et al., 2001; Devagi et al., 2007). Moreover, several previous studies have suggested that trace metal contamination of soils and plants in the vicinity of ore smelters depends upon climatic factors and distance from the smelter since the most detailed data available have usually been gained by sampling within less than 10 km from an identifiable source while at greater distances, especially within urban areas, fallout patterns are usually obscured by pollution from other industries and by general urban contamination (Beavington 1973; Cartwright et al., 1976). As shown in chapter 4 and Tables 5.8-5.11, there are variations between different sampling locations and periods, part of which might be due to the different analytical methods employed. Also it is argued that trace metal concentrations in harvested vegetables often show notable variations from year to year, even at the same location in the field. The reason could be variable emission rates, atmospheric transport and deposition processes, and plant uptake (Voutsa et al., 1996). As it is clear from Tables 5.8-5.11, leafy vegetables show higher accumulation of trace metals comparing to fruit vegetables, atmospheric deposition and gaseous emission from traffic have been considered as factors for Pb contamination, since Pb showed a tendency to concentrate in leaves compared to other parts of the vegetables (Devagi et al., 2007; Kachenko & Singh, 2006). Therefore, it could be suggested that cultivation of leafy vegetables for human consumptions in the Port Kembla area should be avoided (Devagi et al., 2007; Kachenko & Singh, 2006).

147