Health Risk assessment

To whom it may concern,

I am looking over a problem for my health risk course, and am having difficulties for an assignment...

The assignment reads as follows.

"The city is proposing to re-condition a high-level bridge next summer (May to September- Summer months)  They will be sand-blasting the structure to remove the existing coat of paint before re-surfacing.

The old paint contains high very high level of lead.  The City's proposal calls for an enclosed working area and the control of dust by exhaust system.  It was calculated that the system could ensue a minimum of 90% containment of lead dust"

I am to identify all those that may be affected by this project (with explanation if needed, i.e. where will the individual pick-up the dust), and rank them according to the order of the importance.  Including any relevant information or assumptions.

I don't need to explain the toxicity of lead.

I am assuming those most affected would be the workers sandblasting the lead paint.  

Also of importance.
-River under the bridge... which leads to a water treatment plant... however it is my understanding that this will not be a primary concern because they can monitor the lead, and filter it out..

-Playground near the bridge... (Under bridge about 200 yards away)
-Football field near bridge... (Under bride about 100 yards away from bridge)
-A road travels under one end of the bridge (perpendicular to the bridge)
-Footbridge near the bridge

Included is an actual photo of the bridge... the park, and football field can bee just seen in the background.

what is your professional opinion on what is of most concern.. I am thinking the workers, and possibly the children playing at the park (but am not sure the lead particles will travel that far, nor will have that high of a response to be of concern)