The Effects of Road Transport on Freshwater and Marine Ecosystems

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100 trace metals (probably Cu and Zn) were responsible for the toxicity to sea urchins. Tests using Ceriodaphnia indicated that the toxicity observed arose from organophosphate pesticides present in the stormwater (e.g., diazinon and chlorpyrifos). <strong>The</strong> findings reflected the known toxicity <strong>of</strong> these constituents to Ceriodaphnia. <strong>The</strong> authors concluded that the concentrations <strong>of</strong> Cu and Zn were sufficient to account for between 55 and 95% <strong>of</strong> the observed toxicity depending upon the storm event. Copper and Zn were also identified as significant toxicants in stormwater by Cooke & Lee (1995, in Schiff et al. 2002). <strong>The</strong> examination <strong>of</strong> the intrusion <strong>of</strong> stormwater plumes into Santa Monica Bay showed that the plumes were relatively short-lived and plumes unlikely to persist for more than several days depending upon the size <strong>of</strong> the storm event and the sea-state in the coastal area at the time (Washburn et al. 2003). Bay et al. (2003) note that similar TIE testing undertaken in southern California identified Zn as the primary toxicant. <strong>The</strong> comparison <strong>of</strong> road/motorway stormwater quality with general urban stormwater quality in Section 4 showed that road run<strong>of</strong>f generally has similar concentrations <strong>of</strong> Zn and Cu to general urban run<strong>of</strong>f. Concentrations <strong>of</strong> dissolved Cu and Zn have been reported in New Zealand at concentrations very similar to those identified above. It is likely therefore that in the case <strong>of</strong> marine species sensitive to Cu or Zn, toxicity responses may occur in situations where stormwater plumes in the coastal environment occur to dilutions <strong>of</strong> about 10%. A summary <strong>of</strong> relevant water quality guidelines and criteria for the protection <strong>of</strong> marine aquatic resources that may be used by water quality managers to assess the relative impacts <strong>of</strong> changes in receiving water quality is presented in Table 7.1. <strong>The</strong> data identifies both chronic and acute guidelines and criteria for metals and a limited number <strong>of</strong> organic compounds that have assigned guidelines or criteria. From a comparison <strong>of</strong> the data presented on the contaminant concentrations present in urban run<strong>of</strong>f and specific road/highway run-<strong>of</strong>f in Chapter 4 with the data in Table 7.1, it is evident that water-borne toxicity does not appear to be <strong>of</strong> concern for most metals. Based on average dissolved concentrations <strong>of</strong> Cu and Zn identified earlier (e.g., 7.5 and 68 mg/m 3 respectively) dilutions <strong>of</strong> about 6 times for Cu and 4.5 times Zn would reduce concentrations below the ANZECC (2000) triggers. Table 7.1 - Summary <strong>of</strong> water quality guidelines for potential toxicants derived from transport emissions discharged to marine aquatic ecosystems (all data mg/m 3 ). Parameter ANZECC (2000) USEPA (2002) 95% protection Acute (CMC) Chronic (CCC) Cadmium 5.5 40 8.8 Chromium Copper 1.3 4.8 3.1 Lead 4.4 210 8.1 Nickel 70 Zinc 15 90 81 Benzene 700 5100 a 700 a Total PAH - 300 a - Acenaphthene - 970 a 500 a Fluoranthene - 40 a 16 a Naphthalene 70 2350 a - Notes: a = criteria not derived, LOEL presented. However, as Timperley (2003) noted, concentrations <strong>of</strong> both elements are <strong>of</strong>ten much higher during the first flush phase <strong>of</strong> stormwater discharge from roads (refer Section 4). With concentrations <strong>of</strong> dissolved Cu and Zn many times the EMCs, moderate dilution would be required to eliminate toxicity due to dissolved Cu and Zn. Toxicity issues are likely to be greater within estuaries with limited mixing compared to open coastal areas. In determining the significance <strong>of</strong> road stormwater discharges, the key issue is the scale at which toxicity might be evident. Bay et al. (2003) reported that toxicity from Bollana Creek in Santa Monica Bay was evident 2 km alongshore and 1 km <strong>of</strong>f-shore. <strong>The</strong> Ballona Creek Kingett Mitchell Ltd Resource & Environmental Consultants
101 catchment is large (about 229 km 2 ) compared to many urban catchments in New Zealand. For example the many catchments in Auckland City add up to about 153 km 2 with catchment areas ranging from 0.6 km 2 to 15 km 2 . In urban areas such as Waitakere City, there is about 16 km 2 <strong>of</strong> catchment draining to the Whau estuary and about 25 km 2 draining to Henderson Creek (and not all is urban). It is likely that in New Zealand, the discharge <strong>of</strong> stormwater to open coastal environments (e.g., as occur along the East Coast Bays <strong>of</strong> North Shore City) are unlikely to result in toxicity to sensitive marine species. <strong>The</strong> discharge <strong>of</strong> roading and urban stormwater to enclosed estuarine environments has the potential to have some toxic effects on sensitive marine species within these environments. At least a 10 fold dilution is required, to ensure that potential toxic effects associated with dissolved Cu and Zn in road run<strong>of</strong>f are avoided. In most situations in urban areas <strong>of</strong> New Zealand, road run<strong>of</strong>f is not isolated from general urban stormwater (e.g., from buildings, commercial and industrial premises and from road surfaces affected by non roading activities). This may in some situations provide dilution prior to discharge but may also provide additional contaminants contributions. Overall, the toxicity testing carried out in New Zealand by Hickey et al. (1997) has demonstrated that the toxicity <strong>of</strong> urban stormwater is variable with stormwater from a carpark (Unitec in Auckland) being relatively non-toxic. Hickey et al. (1995) concluded that a dilution <strong>of</strong> some three times may be required to ensure that there is no water column toxicity after discharge. It was noted in the study that toxicity was lower than expected. Contaminants other than metals were suggested as having a strong involvement in toxicity. Work undertaken in the United States has shown that toxicity to sensitive marine species can occur in near shore coastal areas in situations where stormwater discharges are not diluted sufficiently. Studies have determined that a dilution <strong>of</strong> typically 90% is required to eliminate toxicity to sensitive species. Toxicity is more likely to occur in locations where dilution is poor. Such locations include embayments and estuaries in harbours and estuaries. Given the relatively small size <strong>of</strong> most New Zealand road and urban catchments, discharge volumes from open coastal stormwater outfalls are typically small with adequate dilution to minimise the risk <strong>of</strong> acute toxicity. 7.4 Sediment Quality 7.4.1 Introduction As discussed in Section 4, particulate matter settlement in estuaries and coastal areas is assisted by flocculation. Coarse sediment zones can <strong>of</strong>ten be observed adjacent to coastal stormwater discharges. <strong>The</strong> extent <strong>of</strong> this zone will be dependent upon site-specific factors. <strong>The</strong>se include the discharge to receiving environment ratio and the local hydrodynamic environment. Increased sediments concentrations have been identified in a number <strong>of</strong> studies around New Zealand where urban stormwater discharges or vehicle emissions occur adjacent to the marine environment. 7.4.2 Intertidal 7.4.2.1 Intertidal areas and Salt Marsh As described in Section 4, aerial deposition has the potential to result in the build-up <strong>of</strong> vehicle emission sourced contaminants. Build-up will be especially pronounced adjacent to bridges, causeways and motorways alongside intertidal areas. In New Zealand, Kennedy (1976 unpublished) examined the distribution <strong>of</strong> trace elements in sediments in salt marsh adjacent to a road around Pauatahanui Inlet near Wellington carrying 4,900 VPD. Sediment cores taken close to the road showed evidence <strong>of</strong> enrichment by Cu, Pb, and Zn. Elevated concentrations <strong>of</strong> the dominant contaminants emitted by motor vehicles (Cu, Pb, Zn) were found adjacent to the road and were detectable to a short distance from the road (15 m). A further study at Pollen Island in Auckland (Kennedy ~1980 unpublished) found that moderate Kingett Mitchell Ltd Resource & Environmental Consultants
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The Effect
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ii 4.2 Particulates in Urban Run<st
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iv 7. IDENTIFICATION OF ENVIRONMENT
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vi MW Molecular weight N Nitrogen N
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2 1. Moncrieff, I.; Kennedy, P. 200
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6 mg/kg) and Zn (25-34,500 mg/kg).
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26 Figure 4.1 - Variation in the co
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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
Page 60 and 61: 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 112 and 113: 102 concentrations of</stro
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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