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The Effects of Road Transport on Freshwater and Marine Ecosystems

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16<br />

An examinati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> the internati<strong>on</strong>al <strong>and</strong> New Zeal<strong>and</strong> gutter dust chemistry data shows that the three<br />

most comm<strong>on</strong>ly identified c<strong>on</strong>taminants are copper (Cu), lead (Pb) <strong>and</strong> zinc (Zn). Increases in the<br />

c<strong>on</strong>centrati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> cadmium (Cd) are also reported. <str<strong>on</strong>g>The</str<strong>on</strong>g>se increases are not unexpected given the<br />

available sources <str<strong>on</strong>g>of</str<strong>on</strong>g> these c<strong>on</strong>taminants <strong>on</strong> roadways.<br />

A range <str<strong>on</strong>g>of</str<strong>on</strong>g> other trace <strong>and</strong> major elements will be present in street <strong>and</strong> gutter dusts due to the wide<br />

range <str<strong>on</strong>g>of</str<strong>on</strong>g> elements present in the general urban envir<strong>on</strong>ment <strong>and</strong> released from motor vehicles (Refer<br />

Kennedy 2003). <str<strong>on</strong>g>The</str<strong>on</strong>g> c<strong>on</strong>centrati<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> these elements will depend up<strong>on</strong> the overall c<strong>on</strong>tributi<strong>on</strong> from<br />

sources <strong>on</strong> motor vehicles relative to other sources. It is evident from the available data <strong>on</strong> street<br />

dusts that a number <str<strong>on</strong>g>of</str<strong>on</strong>g> elements are present in road dusts <strong>and</strong> sediments in higher c<strong>on</strong>centrati<strong>on</strong>s<br />

than would be expected naturally. A number <str<strong>on</strong>g>of</str<strong>on</strong>g> these are associated with various motor vehicle<br />

emissi<strong>on</strong> sources (refer Secti<strong>on</strong> 2). Apart from the more comm<strong>on</strong> elements such as Fe, Pb, Cr, Ni,<br />

Cu, Cd those elements present in higher c<strong>on</strong>centrati<strong>on</strong>s than background include antim<strong>on</strong>y <strong>and</strong><br />

molybdenum.<br />

Table 3.5 - Selected internati<strong>on</strong>al gutter dust metal c<strong>on</strong>centrati<strong>on</strong>s (all data mg/kg dry<br />

weight unless noted).<br />

Element Brockbank et al. (1999) Lau & Stenstrom Li et al. Yim & Nau<br />

(2001)<br />

(2001)<br />

Mascot, Gymnea, Los Angeles H<strong>on</strong>g<br />

Sydney Sydney<br />

K<strong>on</strong>g<br />

Cadmium 0.4-1.3 0.2-1.2 1 (5)* 3.77 7.6<br />

Copper 97-280 51-330 236 (221) 173 635<br />

Chromium - - 29 (47) - -<br />

Ir<strong>on</strong> % 1.6-2.9 2.6-3.4 - - -<br />

Lead 230-1600 520-1600 144 (349) 181 1,287<br />

Manganese 220-450 230-340 - - -<br />

Nickel - - 26 (64) - -<br />

Zinc 440-850 300-560 367 (974) 1,450 2,902<br />

Notes: * - whole sample <strong>and</strong> (

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