Heavy metals in sands of sandboxes: health risk associated with their quantities and form of occurrence in some spas of Poland

Abstract

The authors dealt with some hazardous elements, i.e. As, Cd, Co, Cr, Cu, Ni, Pb and Zn, contained in sands of the sandboxes localized in playgrounds of seven spas in southern Poland (CEE). The following determinations were made: the total contents of metals, the most mobile metals (water-leachable fraction) and the metals available to plants and organisms (CaCl₂- and EDTA-extractable fractions). The totals of the metals are below the upper limits of the values recommended for soils of the protected areas (type A). The mobility of the metals is low: the forms leachable with water range from 0.7% of the total content (TC) of Pb to 13.4% TC of Cd. The forms available to living organisms contain considerably higher quantities of the metals: from 2.3% TC of Ni to 22.6% TC of As in CaCl₂-extractable fractions and from 0.7% TC of Cr to 82% TC of As in EDTA-extractable fractions. An assessment of the health risk indicates that children are exposed to the metals present in the sandboxes mostly due to inadvertent swallowing of "dirt" from their hands. The highest are the HQ_ingestion indexes of As and Cr, both for the 3-year-old permanent spa residents (5.74E−02 and 1.71E−02, respectively) and the spa visitors of the same age (7.47E−03 and 2.22E−03, respectively) and the 6-year-old residents (4.31E−02 and 1.28E−02, respectively) and visitors (5.60E−03 and 1.66E−03, respectively). The health risk indexes HI in the case of non-cancerogenic substances for children 3 and 6 years old are for spa residents, 9.59E−02 and 7.19E−02, respectively, and for children visitors, who are exposed to environmental factors for a much shorter time than the residents, 1.25E−02 and 9.35E−03, respectively. All the risk indexes have their values significantly below 1, which proves the lack of deleterious effects resulting from the exposition of children to the elements considered. The children of both age groups, exposed to the cancerogenic substances, are endangered mainly by As. The risk values of the cancerogenic As for 3- and 6-year-old children residents are 1.27E−06 and 1.90E−06, respectively, and for children visitors of the same ages 1.65E−07 and 2.47E−07, respectively. These values are significantly lower than a permissible level of "1∙10E-05" and means that also in this case, the health risk is minimal. The risk values calculated for the remaining metals are much lower and follow the sequence Cr > Co > Cd. However, an adverse impact of some sand-contained pollutants that are attributed to the motor traffic (Cu, Zn, Ni, Cr, Co and Pb) and low emissions (mainly As and Cd) has been established in the spa resorts in question.

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