Table 1.

Study of arsenic and chromium topsoil levels (mg kg⁻¹), in interpolation by towns and by strata of proximity to industrial emissions

	N	Mean ± SD	Min	P(25)	P(50)	P(75)	Max
All samples (13317)
As		15.060 ± 40.517	0.100	5.300	9.000	15.300	2510.000
Cr		29.790 ± 45.144	0.500	15.600	23.200	33.800	2100.000
Interpolation by towns
As	7917	13.790 ± 7.173	1.000	9.106	12.810	16.970	99.370
Cr	7917	26.230 ± 10.161	6.458	20.230	24.990	29.860	243.700
Towns without emissions at <5 km
As	7037	12.650 ± 7.267	1.000	8.976	12.650	16.710	99.370
Towns with emissions at <5 km
As	880	14.560 ± 6.330	1.421	9.947	14.560	18.290	42.210
Towns without emissions at <5 km
Cr	6827	26.043 ± 10.256	6.643	20.140	24.840	29.580	243.700
Towns with emissions at <5 km
Cr	1090	27.402 ± 9.469	6.458	21.280	25.970	31.830	81.100

N number of towns