Urinary nickel in children exposed to petcoke pollution

Abstract

Petcoke is a remnant of the oil refining process that contains Ni and other heavy metals. Undesired human exposure to these compounds may result from petcoke combustion in plants located in the vicinity of the cities. To compare levels of urinary Ni in schoolchildren residing in cities exposed and not exposed to petcoke pollution. A cross sectional study was done in schoolchildren aged 7 to 8 years old in two cities in northern Chile: Mejillones (n = 59), near to a petcoke plant, and Tocopilla (n = 56) as the reference city. First, morning urinary samples were collected and urinary Ni was determined by Atomic Absorption Spectrometry. Socioeconomic and environmental exposure information of families was obtained applying a questionnaire to parents. Multiple linear regression was performed to identify other variables that may explain urinary Ni differences among the cities. Median level of Ni was higher in Mejillones (4.9 fig/L) than in Tocopilla (3.9 fig/L). Residing in the exposed city was the most important explaining factor (B = 0.26; IC 0.107 - 0.428). Additionally years of residency was associated with urinary Ni (B = 0.03; IC 0.004 - 0.060). Urinary Ni in schoolchildren is higher in the city exposed to petcoke emissions. The difference does not imply that there are concrete hazards for the population's health. However, it warns about the existence of a higher exposure in places where petcoke is used.