Table 1.

Association between BPb and SPb for 2 New Orleans surveys completed in 2001 and 2017

Soil lead (SPb)	Census tracts (N)	Blood lead (BPb)		Fisher's exact test P value (ref. 35)
2001		≥3.6 µg/dL < 3.6 µg/dL
≥99 mg/kg	137	124	13
<99 mg/kg	137	13	124	4.0 × 10−46
2017		≥1.3 µg/dL < 1.3 µg/dL
≥54 mg/kg	137	113	24
<54 mg/kg	137	27	110	1.6 × 10−26

The median SPb decreased from 99 mg/kg to 54 mg/kg between 2001 and 2017. The median BPb declined from 3.6 μg/dL to 1.3 μg/dL during the interval between the two SPb surveys. The extremely small P values indicate that the decline in BPb is not unrelated to the decline in SPb.