New user?

Revision history [back]

I too think determination of the source may be the most economic solution - is there definitely no lead flashing on the roof?

If it was to be atmospheric lead, the most likely source that springs to my mind would be leaded petrol - is that still used in the area? Since lead is so heavy it isn't likely to hang around in the atmosphere long, so you would expect the source to be fairly close - is the site near a main road or other source of lead?

From there, if it was atmospheric lead, the question would be if it is settling out on the roofs and then being caught up in the first flush, or is the rain stripping the lead from the atmosphere directly. If the former then, as Jeremy suggests, a first flush system is likely to be your best option. My first investigation would be lead analysis of first flush vs subsequent flow.

I too think determination of the source may be the most economic solution - is there definitely no lead flashing on the roof?

As for testing the other materials, yes I'd say that leaving a sample of each in some rapidly mixed demin water at the same pH as your rain for a couple of days would be as likely to dissolve lead as the rain would. Similarly if you have some available roofing you could test that too - I understand that the zink chloride used in electroplating can contain lead.

If it was to be atmospheric lead, the most likely source that springs to my mind would be leaded petrol - is that still used in the area? Since lead is so heavy it isn't likely to hang around in the atmosphere long, so you would expect the source to be fairly close - is the site near a main road or other source of lead?lead? If you concluded that any of these were the source, then I would imagine you would be better replacing them (or lining to stop contact with the water) than trying to subsequently remove the lead.

From there, if it was atmospheric lead, the question would be if it is settling out on the roofs and then being caught up in the first flush, or is the rain stripping the lead from the atmosphere directly. If the former then, as Jeremy suggests, a first flush system is likely to be your best option. My first investigation would be lead analysis of first flush vs subsequent flow.

In terms of treatment technologies, pH correction & coagulation is normally used for lead removal, although this is likely to be too complex for your situation. Orthophosphoric acid is very commonly used for plumbosolvency control, but really removal of the source would be the preferred solution.

I too think determination of the source may be the most economic solution - is there definitely no lead flashing on the roof?

As for testing the other materials, yes I'd say that leaving a sample of each in some rapidly mixed demin water at the same pH as your rain for a couple of days would similar time period should be as likely to dissolve lead as the rain would. Similarly if you have some available roofing you could test that too - I understand that the zink chloride used in electroplating can contain lead.

If you concluded that any of these were the source, then I would imagine you would be better replacing them (or lining to stop contact with the water) than trying to subsequently remove the lead.

If it was to be atmospheric lead, the most likely source that springs to my mind would be leaded petrol - is that still used in the area? Since lead is so heavy it isn't likely to hang around in the atmosphere long, so you would expect the source to be fairly close - is the site near a main road or other source of lead? If you concluded that any of these were the source, then I would imagine you would be better replacing them (or lining to stop contact with the water) than trying to subsequently remove the lead.

From there, if it was atmospheric lead, the question would be if it is settling out on the roofs and then being caught up in the first flush, or is the rain stripping the lead from the atmosphere directly. If the former then, as Jeremy suggests, a first flush system is likely to be your best option. My first investigation would be lead analysis of first flush vs subsequent flow.

In terms of treatment technologies, pH correction & coagulation is normally used for lead removal, although this is likely to be too complex for your situation. Orthophosphoric acid is very commonly used for plumbosolvency control, but really removal of the source would be the preferred solution.

I too think determination of the source may be the most economic solution - is there definitely no lead flashing on the roof?

As for testing the other materials, yes I'd say that leaving a sample of each in some rapidly mixed demin water at the same pH as your rain for a similar time period should be as likely to dissolve lead as the rain would. Similarly if you have some available roofing you could test that too - I understand that the zink zinc chloride used in electroplating can contain lead.

If you concluded that any of these were the source, then I would imagine you would be better replacing them (or lining to stop contact with the water) than trying to subsequently remove the lead.

If it was to be atmospheric lead, the most likely source that springs to my mind would be leaded petrol - is that still used in the area? Since lead is so heavy it isn't likely to hang around in the atmosphere long, so you would expect the source to be fairly close - is the site near a main road or other source of lead?

From there, if it was atmospheric lead, the question would be if it is settling out on the roofs and then being caught up in the first flush, or is the rain stripping the lead from the atmosphere directly. If the former then, as Jeremy suggests, a first flush system is likely to be your best option. My first investigation would be lead analysis of first flush vs subsequent flow.

In terms of treatment technologies, pH correction & coagulation is normally used for lead removal, although this is likely to be too complex for your situation. Orthophosphoric acid is very commonly used for plumbosolvency control, but really removal of the source would be the preferred solution.