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Gold mining (GM) is a major source of metals and metalloids in rivers, causing severe environmental pollution and increasing the exposure risks to the residents of surrounding areas. Mining in Ecuadorian Amazonia has dramatically increased in recent years, but its impacts on Indigenous local populations that make use of rivers are still unknown. The aim of this study was to assess the risks to adults and children caused by the exposure to metals and metalloids in freshwater ecosystems contaminated with tailings released by GM activities in 11 sites of the upper Napo River basin, Ecuador. We selected a carcinogenic and a noncarcinogenic risk assessment method to estimate the hazard index (HI) and total cancer risk (TCR). The concentration of Ag, Al, As, Cd, Cu, Fe, Mn, Pb, Zn, B, and V in water and sediment samples was considered to assess the risks to human health. The calculated HI was 23–352 times greater than the acceptable limits in all sites for both children and adults. Mn and Fe were the main contributors (75% in water and 99% in sediment) to the total calculated risk based on the HI. The calculated TCR for children and adults exceeded approximately one to three times the permissible threshold in all sites. As and Pb contributed up to 93% of the total calculated risk based on TCR for both children and adults. This study demonstrates that the emission and mobilization of metals and metalloids caused by mining activities increase the risk to human health, to which we recommend further monitoring of freshwater contamination in the area and the implementation of preventive health management measures. Integr Environ Assess Manag 2023;19:706–716. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC). Key Points: Areas affected by gold mining in Amazonia have high concentrations of metals and metalloids in the water and sediments.The noncarcinogenic risk, as calculated by the hazard index, was 23–352 times greater than the acceptable limits for both children and adults.The carcinogenic risk to both children and adults exceeded by up to three times the permissible threshold.Our human health risk assessment indicates that Indigenous populations living close to mining areas are exposed to health risks. [ABSTRACT FROM AUTHOR]

This work is a study on the occurrence of emerging pollutants in the northeast Ecuadorian Amazon. Emerging contaminants (ECs)—caffeine, triclosan, estradiol, acetaminophen, nicotine, and ibuprofen—were quantified by gas chromatography–mass spectrometry in rivers and streams of the Amazon basin near the city of Tena, Ecuador. For that, a total of 16 natural water samples were taken in 8 locations. Sampling sites included areas impacted by discharges from inefficient sewage networks in urban areas, wastes from fish farming and non-functional landfill, a stream with few threats, tap water, and treated sewage. Caffeine was found in the 38% of the samples studied while trimethoprim and acetaminophen had an occurrence of 13%. Caffeine was detected at two sites receiving untreated sewage and one site receiving treated sewage with mean concentrations that ranged between 19 and 31.5 μg L−1. Acetaminophen (50.4 μg L−1) and trimethoprim (2 μg L−1) were only detected in the river receiving treated sewage effluent. This is the first assessment of emerging contaminants in the upper Ecuadorian Amazon basin, and our observations highlight the need for better sewage treatment and water quality monitoring in Amazonian cities. [ABSTRACT FROM AUTHOR]

This research project shows the effect of altitude on the emissions of polluting gases from a spark ignition engine (SI engine), considering that in Ecuador and in Latin America, there are topographic variations that affect the conditions of vehicle operation. This work analyzes the emissions of polluting gases generated by a SI engine operating at different heights above sea level. Altitude is a very important factor in the performance of SI engine and in the emissions that it produces. Measurements were developed in three cities with different height above sea level (0, 2.200 and 3.000 masl), at four engine revolutions (idle, 2.000, 3.500 and 4.500 rpm) and at the same hour of the day. The emissions of carbon monoxide (CO), carbon dioxide (CO2) and unburned hydrocarbons (UHC) were measured. The results showed that the engine revolutions are the most important factor in the emission of CO and UHC; as the rpm increase, the percentage of CO is higher and the amount of UHC is reduced; however, in CO2 emissions, altitude has a more significant effect, decreasing as atmospheric pressure drops. Consequently, it is expected that the results achieved will promote future works to reduce harmful emissions to human health. [ABSTRACT FROM AUTHOR]

Mining areas may suffer long-term metal contamination and represent harmful remnants of former mining activities. In the northern Amazon of Ecuador, former mining waste pits are used in Oreochromis niloticus (Nile tilapia) fish farming. Given the high consumption of this species by the local population, we aimed to estimate human consumption risks by determining Cd, Cu, Cr, Pb, and Zn tissue bioaccumulation (liver, gills, and muscle) and genotoxicity (micronucleus essay) in tilapia cultivated in one former mining waste pit (S3) and compare the findings to tilapias reared in two non-mining areas (S1 and S2); 15 fish total. Tissue metal content was not significantly higher in S3 than in non-mining areas. Cu and Cd were higher in the gills of tilapias from S1 compared to the other study sites. Higher Cd and Zn were detected in the liver of tilapias from S1 compared to the other sampling sites. Cu was higher in the liver of fish from S1 and S2, and Cr, in the gills of fish from S1. The highest frequency of nuclear abnormalities was observed in fish from S3, indicating chronic exposure to metals at this sampling site. The consumption of fish reared at the three sampling sites results in a 200-fold higher Pb and Cd ingestion than their maximum tolerable intake thresholds. Calculated estimated weekly intakes (EWI), hazard quotients (THQ), and Carcinogenic Slope Factors (CSF ing) denote potential human health risks, indicating the need for continuous monitoring in this area to ensure food safety not only in areas affected by mining, but in general farms in the region. [Display omitted] • Cd, Cu, Cr, Pb, and Zn accumulation was detected in Tilapia reared in mining waste in non-mining areas in Ecuadorian Amazon. • High genotoxicity was detected in tilapia reared in mining waste. • Fish ingestion from all sampling sites leads to Pb and Cd ingestion 200-fold higher than maximum tolerable intake thresholds. • Potential human health risks due to tilapia consumption are noted. • Continuous monitoring is required to ensure food safety. [ABSTRACT FROM AUTHOR]

Starches from nine potato tubers marketed in Ecuador were evaluated for their in vitro digestibility, morphological, thermal, and pasting properties. Raw starches are resistant to enzymatic hydrolysis, but their digestibility increases significantly after gelatinization. Rapidly digestible starch (RDS) increases from 3.8 to 6.2 folds, while the contents of both slowly digestible starch at 120 min (SDS120) and 240 min (SDS240) decrease from 17.9–34%, and 10.2–34% (raw starch), to 11.2–20.1%, and 4.2–16% (gelatinized starches), respectively. Also, resistant starch (RS) content diminishes from 33.7–45.5% to 8.50–14.8%. In addition, total starch (86–95%), average granular size (26.2–47.23 µm), consists mainly of elliptical or ground granules, and pasting properties (Peak viscosity: 2400–3240 cP; final viscosity: 1236–3507 cP; breakdown: 2236–5424 cP; setback: 510–3477; and pasting temperature 60.6–66.2 °C) differed significantly (p < 0.5). Amylose (21.1–26.7%), and thermal properties (To: 57.1–62.3 °C; Tp: 58.2–63.9 °C; Tf: 59–64.9 °C), except gelatinization enthalpy (67.7–168.6 J g─1), do not differ significantly (p < 0.5). This study provides important information for developing products, mainly those with reduced starch digestibility, using different potato varieties. [ABSTRACT FROM AUTHOR]