Abstract

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 ℜ. 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.

Highlights

  • During the 1960s, instruments became available for analyzing small quantities of physiologically relevant Pb [1]

  • Children’s blood Pb assisted in finding sources of environmental Pb, a secondary prevention practice because exposure sources were found after children are exposed

  • List issues for each analytical method, provide soil Pb and children’s blood Pb results, and suggest factors that play an essential role in children’s exposure from soil Pb

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Summary

Introduction

During the 1960s, instruments became available for analyzing small quantities of physiologically relevant Pb [1]. The atomic absorption spectrometer (AAS) was applied to monitoring children’s blood Pb and clinical outcomes of Pb. Increasing clinical awareness about health damage from Pb exposure became known, and the response was a stepwise reduction of blood Pb guidelines. Children’s blood Pb assisted in finding sources of environmental Pb, a secondary prevention practice because exposure sources were found after children are exposed. The same instruments were repurposed as environmental research tools for the monitoring of Pb in air, water, and soil media, and analytical instruments became available as tools for primary prevention to avert children’s exposure in the first place. This study was instigated when student researchers discovered elevated soil Pb on residential properties in the small city of St. John’s, Newfoundland and Labrador

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