Pollution from plastic debris and microplastics (MPs) is a worldwide issue. Classified as emerging contaminants, MPs have become widespread and have been found not only in terrestrial and aquatic ecosystems but also within the food chain, which affects both the environment and human health. Since the outbreak of COVID-19, the consumption of single-use plastics has drastically increased, intensifying mismanaged plastic waste in countries such as Ecuador. Therefore, the aim of this review is to 1) summarize the state of MP-related knowledge, focusing on studies conducted with environmental matrices, biota, and food, and 2) analyze the efforts by different national authorities and entities in Ecuador to control MP contamination. Results showed a limited number of studies have been done in Ecuador, which have mainly focused on the surface water of coastal areas, followed by studies on sediment and food. MPs were identified in all samples, indicating the lack of wastewater management policies, deficient management of solid wastes, and the contribution of anthropogenic activities such as artisanal fishing and aquaculture to water ecosystem pollution, which affects food webs. Moreover, studies have shown that food contamination can occur through atmospheric deposition of MPs; however, ingredients and inputs from food production, processing, and packaging, as well as food containers, contribute to MP occurrence in food. Further research is needed to develop more sensitive, precise, and reliable detection methods and assess MPs' impact on terrestrial and aquatic ecosystems, biota, and human health. In Ecuador specifically, implementing wastewater treatment plants in major cities, continuously monitoring MP coastal contamination, and establishing environmental and food safety regulations are crucial. Additionally, national authorities need to develop programs to raise public awareness of plastic use and its environmental effects, as well as MP exposure's effects on human health.

The consumption of natural foods is increasingly high, and in recent years, consumers have preferred foods from systems with responsible management of natural resources (organic, hydroponic). However, there are still contradictions regarding the nutritional content of products from these different types of crops. Our study aims to compare, for the first time, the content of antioxidants (ascorbic acid, lycopene, total phenolics, essential fatty acids), micronutrients (copper, iron, manganese, zinc), contaminants (cadmium and lead), and free radical scavenging activity between conventional, organic, and hydroponic tomatoes (Solanum lycopersicum) sold in markets in Quito, Ecuador. Ascorbic acid and lycopene were determined by HPLC/UV-Vis. Total phenolics (Folin–Ciocalteu method) and free-radical scavenging activity (2,2-diphenyl-1-picrylhydrazyl method) were determined via UV-Vis spectrophotometry. Lipid profiles were determined as fatty acid methyl esters through a GC-FID. Trace metals were determined using FAAS (micronutrients), and GFAAS (pollutants). No significant differences (p > 0.05) between antioxidant and micronutrient content among the three types of tomatoes were found. Regarding cadmium and lead, the contents were below the Codex Alimentarius threshold limits. Finally, free radical scavenging activity varied slightly (organic > hydroponic > conventional). Although the samples showed certain differences in antioxidant content, none of the tomato types could be considered nutritionally better because of the high variability of the results.

Several microwave-assisted digestion methods were tested at the Centro de Estudios Aplicados en Química laboratory in Quito, Ecuador, to determine the accuracy and performance efficiency of the mineralization process for the determination of total mercury in fish tissue by cold vapor atomic fluorescence spectrophotometry. The use of MARSEasyPrep high-pressure vessels, low amounts of reagents (1 cm³ HNO₃, 1 cm³ H₂O₂, and 1 cm³ HClO₄), an irradiation temperature of 210 °C, and 35 min of mineralization time resulted in accurate performance, with recoveries of certified reference material DORM-4 between 90.1% and 105.8%. This is better than the Association of Official Analytical Chemists 2015.01 method, which has a reported accuracy of 81%. The repeatability precision and intermediate precision were established at three concentration levels (0.167, 0.500, and 0.833 mg·kg⁻¹) and expressed as the percentage of the relative standard deviation ranging from 1.5% to 3.0% and 1.7% to 4.2%, respectively. Further, the method was satisfactorily applied to analyze fortified samples of tilapia (Oreochromis niloticus), with recoveries ranging from 98.3% to 104.3%. The instrumental limits of detection and quantification were 0.118 µg·dm⁻³ and 0.394 µg·dm⁻³, respectively.

Lead (Pb) is a poisonous metal that affects organs and the nervous system. Its presence in spices such as cinnamon has been identified as a potential human exposure pathway. In late October 2023, a safety alert was issued in the United States regarding four children with elevated Pb levels in their blood after consuming apple-cinnamon fruit puree manufactured and exported by an Ecuadorian company. Thus, this study aimed to determine the Pb content in 61 ground and stick cinnamon samples, from different commercial brands and lots sold in Ecuador. Results showed that ground cinnamon samples had almost twice the level of Pb (0.80 ± 0.75 mg/kg) than stick samples (0.36 ± 0.28 mg/kg). Three ground samples had Pb content above the maximum level established by Ecuadorian and European Union regulations (2.0 mg/kg). A Kruskal-Wallis test showed significant differences in Pb content between ground and stick cinnamon (p < 0.05). The HQ values showed negligible non-carcinogenic effects for children and adults, even at the highest Pb content. However, the carcinogenic risk of ground cinnamon at maximum and mean Pb concentrations was found for the population. Our study highlights the deficiencies in current surveillance systems and the lack of effective national regulations for exposure to foodborne metals.

Environmental pollution allows heavy metals to interact with ecosystems, bioaccumulating and passing through the food chain. Animals and human scan consume contaminated species and reach toxic and harmful concentrations in their organisms. While there are international regulatory frameworks for heavy metal contents, these are not always known or suitable for local conditions. This situation calls for the development of locally-applicable analytical methods for the determination of heavy metal concentrations in common vegetal and animal food products. Two established methods (AOAC999.11, based on sample drying and calcination, and IPNAC-06-00, based on microwave-assisted acid digestion) were comparatively tested at the CESAQ-PUCE laboratory in Quito, Ecuador, to determine their suitability. Sample matrices used were non industrial, non-organic tomato, lettuce, and beef commonly found in local markets. Heavy metals tested were cadmium, nickel, and lead. Test guidelines and comparative parameters were based on AOAC(2002) and included quantification limits, repeatability variation coefficients, intermediate precision percentages, accuracy and calculated expanded uncertainties. Unlike method AOAC999.11, method IPNAC 06-00 performance for all parameters was with in the range of recommended expected values as per AOAC, and was therefore deemed more suitable to be applied under the local CESAQ-PUCE laboratory conditions. The validation of method IPNAC-06-00 demonstrated its local applicability. In addition, IPNAC 06-00 can beused by similar laboratories to assess contaminants concentrations and improve the base line information concerning human exposure to toxic metals.