Residential lead soil screen — smelter legacy — Kabwe, Zambia (Kasanda)

Kasanda township borders the closed Broken Hill lead-zinc mine and carries some of the highest documented residential soil lead on earth, with children's blood-lead far above reference values; grid-sample yards, paths and play areas per the method against WHO-guided residential lead screening thresholds and prioritize households with young children for the remediation list. Standard: WHO/FAO soil metal guidance + EPA SSL analog; SDG 3.9/2.1 Proof: 5-point composite + GPS + Pb + metals ppm

Where

Kabwe, Zambia (Kasanda)

Pay

$85 proposed

This packet is not funded yet, so this figure is a proposed price and not money waiting in escrow. If a buyer funds it, approved proof settles that price onchain. If nobody funds it, approved proof earns provable credit toward the work instead of cash. You see which before you claim, never after.

Proof

5-point composite + GPS + Pb + metals ppm

This is exactly what gets it approved. Nothing settles without it.

Level

intermediate

Open until

2026-08-16

How this work is done

A documented method, so this packet comes out the same whoever does it. Typically 45–90 minutes. Method of record: EPA soil screening (composite surface sample, XRF/field kit)

Bring

• trowel or auger
• clean bucket + mixing tool
• XRF analyzer or metals test kit
• PID for volatiles (if petroleum in scope)
• sample bags + labels
• N95 dust mask
• gloves + eye protection
• GPS phone
• camera

Steps

1. 1. Navigate to the parcel; record GPS; sketch a >=5-point sampling grid.
2. 2. Photograph each sampling point and any visible staining/fill/slag.
3. 3. Collect 0-15 cm cores from >=5 points; combine and mix in the clean bucket; subsample.
4. 4. Run XRF/test kit on the composite; record each metal in ppm.
5. 5. If petroleum is in scope, log PID readings and any odor/staining.
6. 6. Bag/label any lab subsample; complete chain-of-custody.
7. 7. Enter all analytes with units, depth, GPS, photos, and site sketch into the proof record; sign.

If it does not match the plan

• Lead > 400 ppm (residential) -> tag exceedance; advise raised beds / produce-washing / cover; recommend lab confirm.
• Arsenic > site screening level or PID indicating volatiles -> tag; recommend certified-lab confirmation before reuse.
• Suspected asbestos-containing material -> do not disturb; flag and stop.

What counts as done

• >=5-point composite collected at 0-15 cm
• Each screened metal recorded in ppm
• Visible staining/fill/slag noted (or absence)
• GPS waypoint + point photos + grid sketch

Proof is measured against these, not judged by taste.