The Effects of Road Transport on Freshwater and Marine Ecosystems

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102 concentrations <strong>of</strong> Cu, Pb, Ni, Cr and Zn were present in roadside soils. Elevated concentrations <strong>of</strong> Cu, Zn, Pb, Ni and possibly V were detected at distances <strong>of</strong> 20 to 40 m from the motorway edge. Given the nature <strong>of</strong> the motorway in this location, it was assumed that much <strong>of</strong> the concentration increases detected in the intertidal mangroves and salt marsh would have been derived from aerial deposition rather than stormwater. <strong>The</strong> maximum concentrations recorded in the Pauatahanui salt marsh study were Cu (38 mg/kg), Ni (17.8 mg/kg), Zn (157 mg/kg), Pb (78 mg/kg), Cr (54 mg/kg) and in the Pollen Island sediments were Cu (24 mg/kg), Ni (12 mg/kg), Zn (54 mg/kg), Pb (79 mg/kg), Cr (113 mg/kg). A comparison <strong>of</strong> the data from these two studies indicated that the concentrations <strong>of</strong> all elements were below upper threshold sediment guidelines such as the ER-M values <strong>of</strong> Long et al. (1995). <strong>The</strong> elements Cu and Zn were measured close to the road at similar concentrations to the ER-L concentration <strong>of</strong> Long et al. (1995). Only Pb was measured at concentrations above the ER-L and the ANZECC (2000) ISQGlow trigger (close to the road and motorway) in both studies. Internationally there appears to have been little information published describing the impact <strong>of</strong> motor vehicles specifically on the build up <strong>of</strong> contaminant concentrations in inter-tidal environments. 7.4.2.2 Intertidal s<strong>of</strong>t-shore areas A wide range <strong>of</strong> investigations, have been carried in the Auckland region on the effects <strong>of</strong> urbanisation on sediment quality in estuaries from both the Manukau and Waitemata Harbours. <strong>The</strong> studies have presented information on the overall effects <strong>of</strong> urbanisation, not specifically on the effects <strong>of</strong> road transport discharges on such environments. Macaskill (2001) provided an overview <strong>of</strong> trace element data in sediments adjacent to Auckland City; Williamson & Mills (2002) overviewed sediment quality information for the Auckland region as it related to sediment quality guidelines and Kingett Mitchell (2003c) examined coastal sediment quality around North Shore City as it related to sediment quality management. Recently Timperley et al. (2003) identified best estimates for the relative contributions <strong>of</strong> vehicles to total loads <strong>of</strong> contaminants entering coastal areas from Auckland City. <strong>The</strong> proportional load from roads indicated that roads (and therefore motor vehicles) contributed to the build up <strong>of</strong> contaminants in coastal depositional environments. A substantial body <strong>of</strong> information on the distribution <strong>of</strong> the key transport related elements (Cu, Pb and Zn) in sediments in the Auckland region both spatially and temporally through the examination <strong>of</strong> sediment cores is also available (e.g., refer Williamson & Mills 2002, Williamson et al. 2003 etc.,). Webster et al. (2000) examined the distribution <strong>of</strong> metals from sediments adjacent to a stormwater outfall in the Hatea River within the urban area <strong>of</strong> Whangarei. <strong>The</strong> sampling showed that a number <strong>of</strong> metals were deposited in a halo around the stormwater discharge point (Fig. 7.3). Elevated concentrations <strong>of</strong> Fe, Mn, Cu, Zn, Pb and As were measured in sediment adjacent to the outfall with highest concentrations closest to the discharge point. No significant accumulation <strong>of</strong> Cu was found close to the discharge point. <strong>The</strong> findings were considered to generally reflect the environmental mobility <strong>of</strong> the elements. For example Cu present in dissolved form was readily leached from sediments while Pb present in particulate form was poorly leached from sediments. Zinc mobility was midway between the two elements. <strong>The</strong> distribution <strong>of</strong> elements around the discharge point was influenced by the deposition <strong>of</strong> Fe-Mn oxides close to the discharge. Overall, deposition patterns <strong>of</strong> metals and contaminants such as PAHs near roads would predict that concentration gradients would be found in estuarine intertidal sediments exposed to vehicle emissions. <strong>The</strong> gradients are however, not as defined as those seen in soils adjacent roadsides, as the sediments are subject to the influence <strong>of</strong> tidal action that may remove some <strong>of</strong> the depositing material through hydrodynamic processes. In estuarine and coastal environments <strong>of</strong> low energy, haloes <strong>of</strong> contamination by key elements would be expected to be found in sediments. <strong>The</strong> scale <strong>of</strong> effects would be very dependent upon the discharge volume, sediment loading and the physical stability <strong>of</strong> the sediment adjacent to the discharge. Scales <strong>of</strong> influence for small stormwater discharges are likely to <strong>of</strong> the order <strong>of</strong> 10-20 m depending on the contaminant and its load discharged from the outfall. Kingett Mitchell Ltd Resource & Environmental Consultants
103 7.4.3 Subtidal <strong>The</strong> accumulation <strong>of</strong> contaminants in subtidal sediments adjacent to stormwater discharges has been examined and reported for several locations in New Zealand. For example: Accumulation <strong>of</strong> metals in sediments adjacent to stormwater outfalls in the central business area <strong>of</strong> Wellington (Bolton-Ritchie et al. 1999). Accumulation <strong>of</strong> metals in sediments adjacent to stormwater outfalls draining the central business area <strong>of</strong> Auckland City (Priestley 1998). Figure 7.3 - Major and trace element distribution in sediments adjacent to a stormwater drain in the Hatea River estuary (From Webster et al. 2000) (Fe %, all other concentrations mg/kg, axis in metres). When the concentrations recorded by Bolton-Ritchie and Priestley are compared to sediment quality guidelines such as ANZECC (2000) it is evident that concentrations <strong>of</strong> key road transport metals exceed sediment quality guidelines. A considerable amount <strong>of</strong> work has been carried out on the prediction <strong>of</strong> effects resulting from the accumulation <strong>of</strong> contaminants in sediments from urbanised estuaries. Williamson et al. (1999) surmised that concentrations <strong>of</strong> Cu, Pb and Zn in Auckland estuaries will exceed sediment quality guidelines identifying the level at which biological effects are expected to occur. For example, the work predicted Kingett Mitchell Ltd Resource & Environmental Consultants
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iv 7. IDENTIFICATION OF ENVIRONMENT
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vi MW Molecular weight N Nitrogen N
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28 Figure 4.2 - Variation in the co
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30 Metal Cu Cd Pb Zn Table 4.6 - Su
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32 probably reflect lower traffic d
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34 (1995) provide a general review
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36 Further data can be found in the
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38 by ARC (1994) indicated that TPH
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40 Cations/Anions Common ionic cons
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42 Catchpits Between the street sur
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44 5 PATHWAYS & FATE OF CONTAMINANT
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46 The material wh
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48 crystalline species present were
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50 Figure 5.1 - Percentage
Page 62 and 63: 52 short (e.g., < 1 day). In water,
Page 64 and 65: 54 5.4.2 Dispersion Dilution and di
Page 66 and 67: 56 5.6 Summary The
Page 68 and 69: 58 6.2 Freshwater Ecosystems 6.2.1
Page 70 and 71: 60 General Assessment Tools Commonl
Page 72 and 73: 62 3. Increasing sediment inputs. 4
Page 74 and 75: 64 considered that taxa richness wa
Page 76 and 77: 66 Freshwater macro-invertebrate me
Page 78 and 79: 68 runoff to fish
Page 80 and 81: 70 deposition, tracking of<
Page 82 and 83: 72 one factor used to classify orga
Page 84 and 85: 74 Zinc Measurement of</str
Page 86 and 87: 76 in stormwater and receiving wate
Page 88 and 89: 78 minute; sub-mitochondrial partic
Page 90 and 91: 80 Toxicity tests have undertaken u
Page 92 and 93: 82 High molecular weight PAHs are t
Page 94 and 95: 84 Note: Sources refer Table 5.2. F
Page 96 and 97: 86 Although a range of</str
Page 98 and 99: 88 Bioaccumulation can be assessed
Page 100 and 101: 90 Figure 6.2 - metal concentration
Page 102 and 103: 92 6.5.3 Bioaccumulation of
Page 104 and 105: 94 Water Stormwater quality data fr
Page 106 and 107: 96 7. IDENTIFICATION OF ENVIRONMENT
Page 108 and 109: 98 3. Echinoderm (Fellaster zelandi
Page 110 and 111: 100 trace metals (probably Cu and Z
Page 114 and 115: 104 that “concentrations
Page 116 and 117: 106 A large amount of</stro
Page 118 and 119: 108 A review of se
Page 120 and 121: 110 Samples of man
Page 122 and 123: 112 grazers such as mud flat snails
Page 124 and 125: 114 8. OVERVIEW 8.1 Vehicles as sou
Page 126 and 127: 116 The quality <s
Page 128 and 129: 118 International studies have show
Page 130 and 131: 120 A number of st
Page 132 and 133: 122 construction. Center for Resear
Page 134 and 135: 124 Carey, J.; Cook, P.; Ciesy, J.;
Page 136 and 137: 126 Ellis, J. B. 1986: Pollutional
Page 138 and 139: 128 Harrop D. O. 1984: Stormwater r
Page 140 and 141: 130 Kennedy, P. C.; Kjellstrom, T.
Page 142 and 143: 132 Maltby, L. A.; Boxall, D. M.; F
Page 144 and 145: 134 Novotny, V.; Muehring, D.; Zito
Page 146 and 147: 136 Ruck, J. 1998: Evaluation <stro
Page 148 and 149: 138 Terracciano, S. A.; O’Brien,
Page 150 and 151: 140 Webster, J. G.; Brown, K. L.; W
Page 152: 142 10. ACKNOWLEDGEMENTS Thanks to
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The Effects of Road Transport on Freshwater and Marine Ecosystems

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