Publicações 2025

Assessment of risk to human health associated with the consumption of contaminated groundwater in the Western Brazilian Amazon

Josilena de Jesus Laureano, Elisabete Lourdes do Nascimento, Caryne Ferreira Ramos, Daíse da Silva Lopes, Luiza Fernanda Silva Pavanello, Tiago de Oliveira Lima, Alan Gomes Mendonça, Ana Lúcia Denardin da Rosa, Walkimar Aleixo da Costa Junior, Maria Cristina N. do N. Recktenvald & Wanderley Rodrigues Bastos

DOI: https://doi.org/10.1007/s10653-025-02491-z

Abstract:

The present study evaluates the risk to human health associated with the consumption of groundwater in municipalities in the Western Brazilian Amazon (Jaru, Ouro Preto do Oeste, Ji-Paraná and Presidente Médici, all in the state of Rondônia). Water was collected directly from wells with an underground collector and PET bottles between 2017 and 2019, in periods (low water, high water, Transition high water/low water). Nitrite and nitrate analyses were carried out using spectrophotometry (APHA, Standard methods for the examination of water and wastewater, Washington, 2017; EPA, Technical Resource Document, EPA/600/4-79/020 Disponívelem, 1971). Trace elements were detected by inductively coupled plasma-optical emission spectrometry. The hazard quotient was obtained from the ratio between the exposure level and the acceptable level for each substance present in the samples, and the hazard index resulted from the sum of the hazard quotients found for each substance. We found that the groundwater in the study areas is improper for human consumption in accordance with Brazilian regulations. Concentrations were found above the maximum values permitted by the Edict on Potability of Water for Human Consumption (PRC Edict 5/2017, as amended by GM/MS Edict 888/2021), and the World health organization standard for 2017 for Al (< 200 µg L⁻¹), As (< 10 µg L⁻¹), Ba (< 700 µg L⁻¹), Fe (< 300 µg L⁻¹), Mn (< 100 µg L⁻¹), Pb (< 10 µg L⁻¹), Zn (< 5,000 µg L⁻¹), and nitrate (< 10,000 µg L⁻¹). The results of the risk assessment indicated that the values were above the recommended levels (< 1) in 75.3% of the samples analyzed, meaning that people in the areas studied are highly exposed to contaminants that are harmful to human health.

Seasonal dynamics of trace elements in water and sediments (suspension and bottom) in the Madeira River Basin, Western Amazon

Walkimar Aleixo da Costa-Júnior, Ronaldo de Almeida, Izidro Ferreira de Sousa-Filho, Dario Pires de Carvalho, Luiz Drude de Lacerda & Wanderley Rodrigues Bastos

DOI: https://doi.org/10.1007/s10661-025-13855-4

Abstract:

Trace elements are ubiquitous global pollutants in modern society and are present in water and biota associated with natural and anthropogenic sources. In this context, this study reports the dynamics of trace elements in the Upper Madeira River Basin, a region that has undergone major environmental changes in the past decades, such as deforestation, mining, and the installation of two large hydroelectric power plants. Bottom sediment, water, and suspended particulate matter (SPM) were collected to determine water quality parameters and trace elements concentrations, quantified by ICP-OES. The average electrical conductivity of water was higher in the Madeira River (110.6 ± 44.4 µS cm⁻¹) than in its tributaries (59.0 ± 49.1 µS cm⁻¹). The Madeira River water has a pH close to neutral (7.0 ± 0.8), compared to the slightly acidic water of the tributaries (6.3 ± 0.9). The average dissolved oxygen in the Madeira River water samples was 6.9 mg L⁻¹, significantly higher than in the tributaries (3.9 mg L⁻¹). The sediment from the Madeira River has higher concentrations of As, Cu, Mn, Ni, Sr, and Zn than the tributaries but lower concentrations of Ba, Mn, Pb, Sr, V, and Zn in the SPM. Trace elements concentrations in the SPM remained relatively constant during the study period and were controlled by seasonality. The average concentrations of trace elements in water, suspended solids, and bottom sediments of the Madeira River Basin were comparable to other non-impacted aquatic ecosystems and can be considered regional environmental background values. In addition, concentrations were below the limits established by the World Health Organization and Brazilian regulations, for human consumption and conservation of aquatic life except, for occasional peaks of Ni and Pb concentrations.