Análise de contaminação de solo em obras de paredes de concreto armado moldadas in loco: estudo de caso em um canteiro de obra de condomínio de edificações verticais

Abstract

This study investigates the environmental impacts associated with soil contamination in construction projects that employ cast-in-place reinforced concrete wall systems. Conducted at a construction site in Londrina, Paraná (Brazil), the research involved the collection of four composite soil samples: one from a non-impacted area (control) and three from locations exposed to effluents from concrete, paints, and metallic formwork washing. Laboratory analyses included pH (in water, CaCl₂, and SMP), cation exchange capacity (CEC), phosphorus (Mehlich-1 and Mehlich-3), calcium, magnesium, potassium, sodium, aluminum, sulfur, boron, iron, copper, manganese, zinc, total organic matter, and remaining phosphorus. In addition, ordinary kriging was used to model the spatial distribution of key contaminants. Results showed significant changes in soil chemical properties in the impacted areas. The formwork washing site exhibited the most critical conditions, with pH dropping to 4.7, iron levels increasing from 32.9 to 105.2 mg/dm³, zinc from 0.6 to 5.3 mg/dm³, and organic matter rising from 8.3 to 20.5 g/kg. Kriging-based spatial analysis confirmed elevated concentrations in zones with higher effluent exposure. These findings highlight the environmental degradation potential of certain construction practices and underscore the need for mitigation measures such as decantation and filtration systems connected to the sewage network. The study contributes to a better understanding of the effects of construction activities on soil quality and reinforces the importance of sustainable practices in compliance with environmental regulations.