Agreement of four analytical methods applied to pb in soils from the small city of st. John’s, NewFoundland, Canada

In the small city of St. John’s, NL (2020 population ~114,000), 100% of the soils of the pre-1926 properties exceeded the Canadian soil Pb standard, 140 mg/kg. The Pb was traced to high-Pb coal ash used for heating and disposed on the soils outside. Analytical instruments became available in the late 1960s and 1970s and were first used for blood Pb and clinical studies and repurposed for measuring environmental Pb. The environmental research part of this study compared four common soil Pb analysis methods on the same set (N = 96) of St. John’s soil samples. The methods: The US EPA method 3050B, portable X-ray fluorescence spectrometry (pXRF), The Chaney–Mielke leachate extraction (1 M nitric acid), and the relative bioaccessibility leaching procedure (US EPA method 1340). Correlation is not the same as agreement. There is strong agreement (Berry–Mielke’s Universal R) among the four soil Pb analytical methods. Accordingly, precaution is normally advisable to protect children from the high-Pb garden soils and play areas. A public health reality check by Health Canada surveillance of St. John’s children (N = 257) noted remarkably low blood Pb. The low blood Pb of St. John’s’ children is contrary to the soil Pb results. Known urban processes causing the rise of environmental Pb and children’s Pb exposure includes particle size, aerosol emission by traffic congestion, and quantities of leaded petrol during the 20th century. Smaller cities had minor traffic congestion and limited combustion particles from leaded petrol. From the perspective of the 20th century era of urban Pb pollution, St. John’s, NL, children have blood Pb characteristics of a small city. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Gonzales C.R.1 , Paltseva A.A. 2, 3 , Bell T.4 , Powell E.T.5 , Mielke H.W.1
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  • 1 Department of Pharmacology, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112, United States
  • 2 School of Geosciences, University of Louisiana, 104 East University Avenue, Lafayette, LA 70504, United States
  • 3 Department of Landscape Design and Sustainable Ecosystems, Agrarian-Technological Institute, RUDN University, Miklukho-Maklaya Street, 6, Moscow, 117198, Russian Federation
  • 4 Department of Geography, Memorial University of Newfoundland, 230 Elizabeth Avenue, St. John’s, NL A1C 5S7, Canada
  • 5 Lead Lab, Inc, 3233 DeSoto, New Orleans, LA 70119, United States
Berry–Mielke’s Universal R agreement statistics; Bioaccessibility; Blood lead; Human exposure; PXRF; Soil extractions; Urban soil
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