Distribution of Arsenic and Risk Assessment of Activities on Soccer Pitches Irrigated with Arsenic-Contaminated Water

Abstract

The aim of this research was to estimate the risk of human exposure to arsenic due to sporting activities in a private soccer club in Mexico, where arsenic-contaminated water was regularly used for irrigation. For this purpose, the total concentration in the topsoil was considered for risk assessment. This was accomplished through three main objectives: (1) measuring arsenic concentrations in irrigation water and irrigated soils, (2) determining arsenic spatial distribution in shallow soils with Geographical Information Systems (GIS) using geostatistical analysis, and (3) collecting field and survey data to develop a risk assessment calculation for soccer activities in the soccer club. The results showed that the average arsenic concentrations in shallow soils (138.1 mg/kg) were 6.2 times higher than the Mexican threshold for domestic soils (22 mg/kg). Furthermore, dermal contact between exposed users and contaminated soils accounted for a maximum carcinogenic risk value of 1.8 × 10−5, which is one order of magnitude higher than the recommended risk value, while arsenic concentrations in the irrigation water were higher (6 mg/L) than the WHO’s permissible threshold in drinking water, explaining the contamination of soils after irrigation. To the best of our knowledge, this is the first risk study regarding dermal contact with arsenic following regular grass irrigation with contaminated water in soccer pitches.

Evaluation of Potential Ecological Risk Index of Toxic Metals Contamination in the Soils

“…It has a total geographical area of around 4.84 hectares and is positioned within 23 • 40 30" N latitude and 100 • 35 27" W longitude (Figure 1). The study area is the Joya Verde soccer sports club, which comprises irrigated lands, including three half-hectare soccer grounds, and vegetative areas, known as non-irrigated lands, surrounding the soccer pitches [14]. Massive amounts of recent as well as historical tailings are reported to have been deposited on the surrounding terrains as a result of mining activities on an unmanaged privately owned land with no restrictions on public access [15][16][17].…”

“…A Garmin Etrex Personal navigator global positioning system receiver was used to geo-locate all of the soil sampling locations. For data quality concerns, duplicate samples were taken from every fifth sampling point to make a total of 77 soil surface samples [14]. As a typical sample, a 1 kg specimen of fresh topsoil was taken from each location and packaged in a sealed plastic bag to preserve it as clean before transferring it to the testing laboratory.…”

“…In a beaker, 1.0 gm of soil was poured, followed by 10 mL of aqua regia (HNO 3 :HCl) with a ratio of 3:1. When assessing total accessible toxic metals in soils, this digestion process is acceptable [14,22]. The different concentrations of digested samples were evaluated for As, Cu, Ni, Pb, and Zn after dilution with deionized water using inductively coupled plasma optical emission spectroscopy (ICP-EOS) [14,23].…”

“…The box and whisker plots in Figure 2 describe the primary information for the toxic metals assessments in this analysis. The high concentration of As was probably due to effluents of nonferrous metal smelting, past mining activities as well as the use of As-contaminated irrigation water [14]. The principal component analysis (PCA) revealed the potential relationships between the various environmental conditions and the identified toxic metals.…”

“…The spatial distribution pattern of the potential ecological risk level (RI) for five different toxic metals contaminations (i.e., As, Cu, Ni, Pb, and Zn) in the soil is shown in Figure 4. For the spatial distribution, the inverse distance weighting (IDW) interpolation technique was applied to evaluate the distribution of potential ecological risk levels for toxic metals in the surface soil, because it is a suitable approach for interpolating regularly spaced specific sampling point data [14]. GIS software was used to map the potential ecological risk level areas and classify them into four categories.…”