Abundance and distribution of cigarette butts on the sand of five touristic beaches in Latin America during the COVID-19 pandemic.

Cigarette butts (CB) and cigarette butt fibers (CBF) are highly abundant and frequent residues on beach sand. Also, they are hazardous waste due to their significant toxicity and potential risk to the ecosystems' biota and the health of beach tourists. This study aimed to determine the abundance and density of CB and CBF found on the active, rest, and service zones of five pilot beaches in Argentina, Colombia, Brazil, Ecuador, and Mexico. The methodology involved collecting CB and CBF in 500 m2 transects of urban tourist beaches using a citizen science-adapted methodology between June 2021 and May 2022, during the COVID-19 pandemic. The abundance and density of CB and CBF, and the Cigarette Butt Pollution Index (CBPI) were calculated. The highest proportion of CB was found in service and rest areas. Bocagrande (CO) reported the highest generation of CB and CBF and a severe CBPI.

Potential use of coconut fibre modified mortars to enhance thermal comfort in low-income housing.

Enhancing the thermal comfort of low-income housing in developing countries located in tropical areas is one of the main challenges for engineers and architects worldwide. The coconut mesocarp fibre (coir) has shown enormous potential for improving some properties of modified concretes or mortars, such as low-weight and high-acoustic isolation. In this study, the potential use of modified mortars by coconut fibres as a facade coating layer to enhance thermal comfort in low-income housing structures was evaluated for the city of Cartagena de Indias, Colombia. An actual typical low-income house of 42 m2 was monitored. Temperature and humidity variations were monitored for 39 days, thermal characteristics of coir-modified mortars were also investigated using differential scanning calorimetry (DSC) and an adaptation of the standard test method of the guarded-hot-cartridge apparatus. The EnergyPlus™ software was used to simulate indoor temperature variations in the studied house. Results show that during the period of 4 h of maximum sunlight radiation with outdoor temperatures in the range of 29-34 °C, coating the cement-sand hollow block structure with a layer of coir-modified mortar could reduce indoor room temperatures by 0.5-1.5 °C, approximately. Thus, there is a potential to enhance the thermal comfort in low-income housing structures with coconut fibre modified mortars while reducing annual energy costs of cooling by 16%, making it affordable for low-income families in the Caribbean region of Colombia.

Plastics and microplastics, effects on marine coastal areas: a review.

Plastics have become strong environmental stressors of coastal marine ecosystems. Their introduction into the marine ecosystem is subjected to different mechanisms, including the inadequate disposal of solid waste and dumping of wastewater. In addition, their chemical composition makes them resistant to variables such as temperature and salinity of water. These polymers are degraded and fragmented mainly due to the action of the waves, which results in the formation of smaller particles called microplastics. Microplastics are characterized by being persistent in the environment due to their low biodegradation, and although they have a maximum size of 5 mm, there is a wide range of sizes suggested by different authors. According to their use, microplastics can be classified as primary when they are recognized at first sight, and as secondary, when they are gradually divided. Microplastics have become a potential risk to the health of marine species due to their small size, and the risk to human health due to their persistence through trophic chains is alarming. Given the potential impact these materials would have in the biota, and the need to assist the different regulatory agencies to develop political acts on the proper management and disposal of microplastics, the aim of this work was to identify different research carried out at international level on established methodologies for studies of identification and quantification of microplastics, bacterial communities, and contaminants adhered to microparticles. Given the above, some methodologies have been identified and used in various studies for the identification and quantification of these materials on beaches. It should be noted that in different countries, there has been an increase in research related to contamination by microplastics on beaches, in which bacterial communities attached to these plastic particles have been also identified. Likewise, not only the risks and threats have been determined for marine species but also for the health of people who frequent tourist places such as beaches.

Performance of a submerged membrane bioreactor system for biological nutrient removal.

A pilot submerged membrane bioreactor coupled with biological nutrient removal was used to treat the primary effluent at a municipal wastewater treatment plant. Long-term experiments were conducted by varying hydraulic retention time from 6 to 8 hours and solids retention time from 20 to 50 days, respectively. The performance was assessed by monitoring key wastewater parameters, including chemical oxygen demand (COD), nitrogen, and phosphorus concentration in individual anoxic, anaerobic, aerobic, and membrane separation zones. Results showed that the tested system can consistently achieve COD, nitrogen, and phosphorus removal efficiencies at 80 to 98%, 70 to 93%, and 89 to 98%, respectively. Effluent COD remained low as a result of efficient solid retention, even though there was great variation in influent quality. However, total nitrogen increased proportionally with influent concentration. At a 50-day solids retention time, higher COD and nitrogen oxides specific utilization rates in the anoxic zone resulted in a high production of nitrogen oxides in the subsequent aerobic zone.