By Ted Floyd (stormwater and car-use reduction activist) – with source list by Elizabeth O’Brien (of The LEAD Group)

The NSW State government has begun several initiatives on stormwater in central Sydney in the second half of 1998. Three total catchment management committees have been formed, covering Sydney Harbour, including The Port Jackson Total Catchment Management Committee which covers the CBD and inner Sydney suburbs. These committees have community, environment group and Aboriginal representatives. Also, the EPA has directed Municipal Councils to develop a catchment management plan with $60 million of funding available for projects.

The LEAD Group asks these catchment committees: do they realise the importance of lead as a problem, in sediments of drains, Sydney Harbour, Botany Bay and other coastal estuaries?

Do the committees know the relative contribution of the different sources of lead in sediments? Run-off from contaminated sites and from buildings being renovated or demolished or just simply losing flaking or chalking leaded paint, need to be assessed for their contribution. Though new paint now contains less than 0.1 % lead, the pavement dusts and soils in older areas, contain the lead from paint and other sources built up over many years. What strategies will the committees use to control, at the source, this lead pollution? How will they control site run-off?

And as for cars as a source of lead in road run-off, The LEAD Group knows that the following will contribute lead to stormwater long after controls are implemented on the consumer product. Eg, even if lead is removed from petrol for the Sydney Olympics, 25 % of the lead from the petrol that has ever been used in a pre 1986 vehicle, remains in the engine and exhaust system, waiting to be loosened by rough roads or harsh driving.

How do cars contribute to lead contamination of road run-off?

The oft-quoted standard list by Maestri et al (1985) of sources of lead in road run-off, is:-

• leaded petrol (auto exhaust),

• tyre wear (lead oxide filler material),

• lubricating oil and grease, bearing wear.

Q: Why are lead acid batteries rarely listed as a source of lead in road run-off?

A: Maybe because the lead producers say they’re "safe", "green" "100% recyclable".

One study cited in The Leichhardt Municipal Council State of the Environment Report, 1996, gives "lead acid battery releases during vehicle accidents" as a "common source" of lead in gutter sediments in inner and outer Sydney. However, it seems likely that lead in lead acid batteries contributes to the lead in road run-off during normal driving as well. That is, the lead sulphate powder that develops on the terminals could be loosened by the vibration.

Even now, 64% of the world’s lead and 71% of Pasminco’s lead goes into producing lead acid batteries, and this is increasing as more and more cars are built. Therefore, this problem will only increase.

In fact all leaded componentry of cars can contribute to lead in road run-off whenever the material is loosened during driving, and especially when the car is smashed or burned and the debris enters the stormwater system. The Ford and Dale study in Leichhardt Council (and outer Sydney) mentioned above, lists "lead wheel weights being flattened on the road or being scraped against gutters" as another common source of lead in gutter sediments and soils.

So, a more complete list (including the Maestri one above) of sources of lead in stormwater from vehicles, would include:

• auto paint (which can still contain 10% lead),

• lead acid batteries,

• wheel balancing lead weights,

• radiator solder,

• terne plated metal (lead plated metal) used for fuel tank lining,

• PVC in vehicle interiors eg mats,

• PVC flexible bumper strips,

• PVC oil and air filters,

• PVC body side moulding and mudflaps etc,

• auto body solder for panel beating (burning and grinding),

• leaded petrol (auto exhaust),

• tyre wear (lead oxide filler material),

• lubricating oil and grease, bearing wear.