Table 2: Sampling sites with horizontal depth.

Local government area in Niger StateLaboratory identification Vertical depth

Paikoro 1PAI-C130 cm
Paikoro 2PAI-C230 cm
Lapai 1LAP-E130 cm
Lapai 2LAP-E230 cm
Mokwa 1MOK-J130 cm
Mokwa 2MOK-J230 cm
Katcha 1KAT-K130 cm
Katcha 2KAT-K230 cm
Bida 1BID-L130 cm
Bida 2BID-L230 cm
Agaie 1AGA-AE130 cm
Agaie 2AGA-AE230 cm
Suleja 1SUL-IE130 cm
Suleja 2SUL-IE230 cm

The numbers 1 and 2 indicate two random locations within a local government area.