Table 1: Summary of geological and sampling information and chemical measurement data.

SampleGeologySampling locationTypeOrganic matter (%)Soil pHTotal As (mg kg−1)Bioaccessible As (mg kg−1)As BAF (%)Total Cr (mg kg−1)Bioaccessible Cr (mg kg−1)Cr BAF (%)Total Ni (mg kg−1)Bioaccessible Ni (mg kg−1)Ni BAF (%)

GBA number 1LGBA12.76.8615312.88.32752.00.741083.33.1
GBA number 2LGBA14.67.181125.44.83021.10.41142.62.3
GBA number 3LGBA13.46.70824.96.02031.40.7882.93.3
GBR number 1LGBR10.46.29844.25.12641.40.5974.04.1
GBR number 2LGBR10.86.41923.84.12741.40.5984.44.5
SA number 11LSR13.06.853378.12.43791.10.31853.92.1
SA number 2LSA12.46.253487.72.24020.90.21904.42.3
SA number 3LSA11.07.013055.61.83820.90.21763.21.8
SR number 1LSR13.85.833926.01.54060.90.22074.42.1
SR number 21LWR12.95.974175.01.24470.80.22184.21.9
WA number 1LWA12.47.122897.42.63211.10.31593.62.3
WA number 2LWA14.37.112307.73.32731.10.41362.92.1
WA number 3LWA12.07.092496.22.52931.10.41473.02.1
WR number 1LWR15.86.982505.92.43421.00.31533.62.4
WR number 2LWR13.97.112806.32.33591.10.31583.62.3
LHA number 1IOLHA7.717.25171.911.0.650.50.8251.45.7
LHA number 2IOLHA8.527.06141.611.4690.60.9281.65.8
LHA number 3IOLHA9.217.27182.111.6680.60.9311.65.3
LHR number 1IOLHR11.37.43384.010.5960.70.7601.32.1
LHR number 2IOLHR9.057.54292.910.1830.60.7461.22.6
SAA number 1IOSAR5.157.11313.611.7510.71.3171.26.9
SAA number 2IOSAA6.296.72503.67.1531.12.1211.57.0
SAA number 3IOSAA8.236.79232.912.4571.32.2211.46.7
SAR number 1IOSAR6.636.92152.214.7520.81.6181.68.7
SAR number 2IOSAR4.907.16182.514.1540.71.3191.68.2
DA number 1LDA16.17.242177.43.43401.40.41544.32.8
DA number 21LDA13.97.282016.43.23641.40.41484.43.0
DA number 3LDA16.07.181787.03.93211.50.51424.53.2
UHR number 11IOUHR12.06.75203.115.3981.11.1603.25.3
UHR number 2IOUHR9.426.88162.414.8800.91.1442.45.4

L: Lias; IO: Inferior Oolite Groups; GB: Great Bourton; S: Shenington; W: Wroxton; LH: Lower Heyford; SA: Steeple Aston; D: Drayton; UH: Upper Heyford; A: allotment; R: residential sampling site. Total and Bioaccessible PHE concentrations as mg kg−1; BAF denotes bioaccessible fraction (%). pH uncertainty is ±0.05 units and organic matter is ±1%. 1indicates samples used for sequential extraction.