This study aims to determine whether differences exist between the presence of microplastics and mesoplastics in fishes of coral reef and mangrove ecosystems, in Isla Grande, Colombian Caribbean. The collection of three species of coral reef (Centropomus undecimalis, Caranx hippos, and Lutjanus synagris) and three species of mangrove from coral reef (Centropomus undecimalis, Eugerres plumieri, and Archosargus rhomboidalis) were found to have ingested microplastics and mesoplastics, with a significantly higher in the mangrove species than in the coral reef species (1.9 vs. 1.6 items/individual). Furthermore, the average abundance and weight of microplastics and mesoplastics were significantly higher in females than in males (p < 0.05) and the abundance of microplastics and mesoplastics in the intestines was significantly higher than in the stomach (p < 0.05). PE, polyester, PVC, and PET were the most abundant polymers among common plastics found in species of the two habitats. Our findings highlight the importance of more rigorous plastic waste management strategies in areas nearby the coast and mangrove habitats.

Microplastics, plastic fragments smaller than 5 mm present in the environment due to the decomposition of larger plastics, can cause damage to various ecosystems and species of pollinating insects, such as Apis mellifera bees. These bees play a crucial role in the ecology and production of honey and pollen, also serving as bioindicators of environmental quality as they are sensitive to contaminants such as microplastics. In this study, we evaluated the presence of microplastics in these insects and their products—pollen, and honey—collected in August 2021 and August 2023 in rural areas (Tabio and Guasca) of Cundinamarca, Colombia, and urban areas (Universidad Nacional de Colombia and Pontificia Universidad Javeriana) of Bogotá, Colombia. Each year, 24 bees, 10 g of honey, and 5 g of pollen were collected per sampling point. Microplastics in bees and their products were identified and quantified by stereomicroscopy, with or without hydrogen peroxide digestion pretreatment. Microplastics were found in bees, pollen, and honey in both periods, with an increase in their quantity observed over time due to increasing environmental pollution. Blue fibers were the most common microplastics, with a greater amount recorded in 2023 compared to 2021.

Wetlands are being contaminated by housing developments, effluents, industrial areas, and poor sanitation, resulting in the presence of plastic polymers and the development of biofilms on these materials, which represent an elevated risk to freshwater fauna and flora. The objective of this study was to characterize mesoplastics and microplastics, collected in the Gualí Wetland, Colombia, as well as to verify the presence of biofilms on such polymers. Nine water samples (36 L per sample) were evaluated at three points of the wetland; the size of the particles was determined by image analysis, the type of polymer through FTIR, and the presence of biofilms by microscopy. A total of 79 items/0.135 m³ were collected, 2 macroplastic items, 53 mesoplastic items, and 24 microplastic items. The presence of fragments (70%) and pellets (41%), with transparent (40%) and white (30%) being the predominant ones, was outstanding. Among the polymers, high-density polyethylene (HDPE) dominated, followed by expanded polystyrene. The results of SEM demonstrated the presence of diatoms on the surface of the plastic polymers. Furthermore, the results showed a greater amount of HDPE mesoplastics and microplastics in the shape of fragments and pellets. In addition, the presence of biofilms on these plastic particles can increase the adsorption of contaminants, negatively affecting this ecosystem. The outcome of this study can be used to identify bacteria that reside in biofilms associated with microplastics and mesoplastics.

The presence of microplastics (MPs) in agricultural soils is a growing concern, especially in rice cultivation systems, where information is limited, particularly in Latin America. Given the economic importance of this crop in Colombia and the generation of plastic waste from some associated practices, it is crucial to determine the presence of MPs related to agricultural activities in soils dedicated to this activity. This study evaluated the presence of MPs in soils and irrigation water of rice crops in Chicoral, Tolima, Colombia, during two contrasting seasons. Soil samples from seven plots (upper, middle, and lower zones) and water samples from seven points along the irrigation canal were collected. MPs were found in all samples, with similar concentrations in water samples collected in the rainy and dry seasons (0.11 ± 0.10 vs. 0.10 ± 0.06 items/m³, respectively), and higher abundance in soil samples during the rainy season (4 ± 2.71 vs 3.62 ± 1.92 items/50 g). Fragments and fibers were the most abundant forms of plastics (53 % water, 55 % soil), predominantly larger than 100 μm and blue in color. Polypropylene (PP) was the most abundant polymer (50 %) in the meso- and macroplastic samples. Our results suggested that MPs contamination in rice crop soils at Chicoral is influenced by irrigation water transport and improper plastic waste management, highlighting the need for further research on their effects on agricultural systems.

Low-density polyethylene (LDPE) sheets (3.0 ± 0.1 cm) received sequential treatment, first by the action of direct-current low-pressure plasma (DC-LPP) with a 100% oxygen partial pressure, 3.0 × 10⁻² mbar pressure, 600 V DC tension, 5.6 cm distance, 6-min treatment. Then, sheets were submitted to TiO₂ photocatalysis at UV radiation at 254 nm (TiO₂/UV) with a pH value of 4.5 ± 0.2 and a TiO₂ concentration of 1 gL⁻¹. We achieved a complementary effect on the transformation of LDPE films. With the first treatment, ablation was generated, which increased hydrophilicity. With the second treatment, the cavities appeared. The changes in the LDPE sheets’ hydrophobicity were measured using the static contact angle (SCA) technique. The photocatalytic degradation curve at 400 h revealed that the DC-LPP photocatalysis sequential process decreased SCA by 82°. This was achieved by the incorporation of polar groups, which increased hydrophilicity, roughness, and rigidity by 12 and 38%, respectively. These sequential processes could be employed for LDPE and other material biodegradation pretreatment.

Background: The co-transformation of solid waste of natural and anthropogenic origin can be carried out through solid-state-fermentation systems to obtain bio-products with higher added value and lower environmental impact. Methods: To evaluate the effect of Pleurotus ostreatus on co-transformation of oxo-degradable low-density polyethylene (LDPE _oxo ) sheets and lignocellulosic biomass (LCB), were assembled two 0.75 L microcosm systems in vertical (VMS) and horizontal (HMS) position. The pre-treated sheets with luminescent O ₂ plasma discharges were mixed with pine bark, hydrolyzed brewer’s yeast and paper napkin fragments and incubated for 135 days at 20 ± 1.0 °C in the presence of the fungus. With the co-transformation residues, biochar (BC) was produced at 300 ± 1.0 °C (BC300) for 1 h, then used to carry out adsorption studies, using the malachite green dye (MG) at pH 4.0, 7.0 and 9.0 ± 0.2. Finally, the biochar was the substrate for the germination of carnation seeds ( Dianthus caryophyllus ) and Ray-grass ( Lolium sp.) in vitro. Results: For HMS, the decrease in static contact angle (SCA) was 63.63% ( p = 0.00824) and for VMS 74.45% ( p = 0.00219), concerning the pristine. Plastic roughness in VMS was higher (26%) concerning the control. Throughout the 135 days, there were fungal growth and consequently laccase (Lac), manganese peroxidase (MnP) and lignin peroxidase (LiP) activities. During the first 75 days, CO ₂ production increased to 4.78 ± 0.01 and 4.98 ± 0.01 mg g-1 for HMS and VMS, respectively. In MG adsorption studies, the highest amount of the colourant adsorbed at both pH 4.0 and 7.0 ± 0.2. Conclusions: Finally, the biochar or the biochar enriched with low concentrations of plant growth-promoting microorganisms and inorganic fertilizer favours the germination of Dianthus caryophyllus and Lolium sp., seeds.