Age-specific time-spent patterns among residents living near gold mine tailings storage facilities in the West Rand, South Africa

Abstract

BACKGROUND: Communities near mine tailings face elevated environmental risks, but age-specific factors, behaviours, and household characteristics remain insufficiently characterised. Understanding community-specific patterns of indoor and outdoor time spent, as well as residential factors, is essential for human health risk assessment across different demographic groups. OBJECTIVES: This study examined age-related time-spent patterns among residents living near mine tailings storage facilities in the West Rand district, South Africa. METHODS: A cross-sectional survey was conducted among 330 households in Kagiso, West Rand. Data were collected on demographics, housing characteristics, and indoor and outdoor time using a pre-tested structured questionnaire. Descriptive statistics were computed to summarise participant characteristics and time-spent patterns. Group differences across five age categories were assessed using Kruskal-Wallis tests with Bonferroni-adjusted Dunn's post-hoc comparisons after testing normality with the Shapiro-Wilk test. RESULTS: Indoor time accounted for 66.6-84.8% per day on weekdays and 76.0-82.7% on weekends, averaging 18.28 ± 3.02 h on weekdays and 19.00 ± 1.99 h on weekends. Young children and elderly participants spent the most time indoors, significantly more than other age groups (p < 0.05). Weekend indoor time increased significantly among children, adolescents, and adults (p < 0.05), but not among young children and elderly participants. Outdoor and recreational time varied significantly by age (p = 0.015), with higher participation among children and adolescents than among other age groups. Post-hoc analyses confirmed significant age-group differences in indoor time and recreation between younger and older participants. SIGNIFICANCE: This study revealed that the time West Rand residents spent indoors was nearly 10 percentage points lower than that reported by the USEPA. Significant demographic group differences suggest that time-spent patterns may lead to differential exposure to indoor and outdoor pollutants. The findings highlight the need for age-specific exposure assessments and tailored environmental health interventions in mine-adjacent communities. IMPACT STATEMENT: This study presents the characterisation of age-specific time-spent patterns among residents of a community near mine tailings. In a South African sample, we showed that indoor and outdoor time-spent patterns differ from the default assumptions in the USEPA Exposure Factors Handbook. Variation observed across age groups indicates that reliance on generic exposure parameters may misrepresent population-specific risks. These findings demonstrate that exposure assessments and interventions must be age-specific, reflecting the distinct patterns and profiles of different demographic groups. Furthermore, they emphasize the importance of locally generated demographic, time-spent, and housing data for accurately characterizing environmental risks in mining-affected communities.