Summary: The municipality of Medellín, Veracruz, México has a type A landfill, whose operation level has recently increased due to landfill closure in the city of Veracruz. The objective of this study is to analyze and evaluate the quality of groundwater surrounding the landfill of the municipality of Medellín., such as hydrogen potential (pH), electrical conductivity (EC), turbidity (T), chemical oxygen demand (COD), total phosphorus (TP), nitrates (NO3 -), total dissolved solids (TDS) and heavy metals Lead (Pb), cadmium (Cd) and copper (Cu) in seven groundwater wells near the landfill during the “north” and dry season. The physicochemical water results from the seven wells analyzed were within the maximum permissible limits of Mexican regulations: turbidity values exceeded international regulations and four wells were found contaminated according to COD levels. The concentrations of Pb and Cd in both seasons were higher than the maximum permissible limits for human consumption in accordance with national and international regulations. Therefore, the results indicated the negative influence of the landfill on groundwater quality.

Resumen: Los rellenos sanitarios se han vuelto una fuente de contaminación de aguas superficiales y subterráneas, debido a la generación de lixiviados que pueden llegar hasta los cuerpos de agua con efectos adversos al ambiente. El municipio de Medellín, Veracruz, México; cuenta con un relleno sanitario tipo A cuyo nivel de operación se ha incrementado recientemente debido a la clausura del relleno sanitario de la ciudad de Veracruz. El objetivo del presente estudio fue analizar la calidad del agua subterránea aledaña al relleno sanitario del municipio de Medellín. Se evaluaron potencial de hidrógeno (pH), conductividad eléctrica (CE), turbidez (T), Demanda Química de Oxigeno (DQO), Fósforo Total (PT), Nitratos, (NO3 -), Sólidos Disueltos Totales (SDT) y metales pesados Plomo (Pb), Cadmio (Cd) y Cobre (Cu) en 7 pozos de agua subterránea próximos al relleno sanitario durante la temporada de “nortes” y estiaje. Los resultados fisicoquímicos del agua de los 7 pozos analizados se encontraron dentro de los límites máximos permisibles de la normatividad mexicana; los valores de turbidez superaron la normatividad internacional y 4 pozos mostraron estar contaminados de acuerdo a los niveles de DQO. Las concentraciones de Pb y Cd en ambas temporadas se encontraron superiores a los límites máximos permisibles para consumo humano de acuerdo con la normatividad nacional e internacional. Los resultados indicaron la influencia negativa del relleno sanitario en la calidad del agua subterránea.

Abstract This study analyzed the impact of leachate from a temporary landfill on soil microbial diversity in Tingo María, Huánuco region, Peru. Three treatments were used: untreated soil (S), addition of stream water (T0), leachate (T1), and leachate treated by coagulation and flocculation (T2), with 828.5 ml/week added in three weekly doses. Soil samples were collected from the Reserved Forest of the Universidad Nacional Agraria de la Selva. Twenty-one randomly distributed soil samples were taken and homogenized for analysis. Soil quality parameters measured included sand, clay, silt, texture, pH, organic matter, nitrogen, phosphorus and potassium. As for microorganisms, viable aerobes, lactobacilli, actinomycetes, fungi, nitrogen-fixing bacteria, and Escherichia coli were quantified using specific culture and counting methods for each of them. To evaluate the impact of the leachate on microbial diversity, equity indices (Shannon and inverse Simpson), dominance indices (complementary Simpson and Berger Parker) and the percentage composition of each microorganism per treatment were used. An ANOVA was performed to estimate differences in microbial diversity, with a Tukey test at a significance level of α = 0.05. The study showed that leachates affect soil microbial diversity, reducing equity and increasing the dominance of certain species such as E. coli. They also alter physicochemical parameters, decreasing organic matter and nitrogen but increasing other elements such as phosphorus and potassium. This could have implications for soil health and functionality.

Abstract Invasive exotic plant species cause serious impacts on the structure and functioning of invaded ecosystems, leaving native species at a disadvantage. Eucalyptus globulus and Pinus halepensis are two species characterized by their wide distribution and high competitive ability. The objective of the study was to compare the allelopathic effect of leaf litter leachate from E. globulus and P. halepensis on the germination, growth and diversity of high Andean wild plant species. Thirty soil samples were collected from the first 10 cm from 1 m2 quadrats. The leachate negatively affected the germination, growth and diversity of wild plant species, particularly eucalyptus leachate. As this is one of the few studies carried out in high Andean areas, it is necessary to carry out studies in natural conditions and on larger time scales, to more accurately evaluate the effects on biodiversity.

Resumen Las especies de plantas exóticas invasoras causan graves impactos en la estructura y funcionamiento de los ecosistemas invadidos, dejando en desventaja a las especies nativas. Eucalyptus globulus y Pinus halepensis, son dos especies caracterizadas por su amplia distribución y alta habilidad competitiva. El objetivo del estudio fue comparar el efecto alelopático del lixiviado de la hojarasca de E. globulus y P. halepensis sobre la germinación, crecimiento y diversidad de especies de plantas silvestres altoandinas. Se colectaron 30 muestras de suelo de los primeros 10 cm a partir de cuadrantes de 1 m2. Los lixiviados afectaron de forma negativa la germinación, crecimiento y diversidad de especies de plantas silvestres, particularmente el lixiviado de eucalipto. Al ser este uno de los pocos estudios hechos en zonas altoandinas, es necesario la realización de estudios en condiciones naturales y en mayores escalas temporales, para evaluar con mayor precisión los efectos sobre la biodiversidad.

Leachate from a composting plant was characterized and applied as a biofertilizer in lettuce crops. Characteristics of untreated (UE) and anaerobically treated (TE) leachate samples were compared. The pH of TE (8.2) increased in relation to the UE (5.2) due to an increase in ammonia nitrogen in TE (1197 mg L-1) compared to UE (859 mg L-1). Anaerobic treatment was efficient in the removal of organic matter from the leachate, evaluated by the decrease of dissolved organic carbon, biochemical oxygen demand, total organic carbon and total solids. K presented the highest concentration (1743 mg L-1) in TE, followed by Mg (135 mg L-1). Cd, Pb and Cr were present at low concentrations in the samples, 0.047, 0.206 and 0.081 mg L-1, respectively. Salmonella, thermotolerant coliforms and viable helminth eggs were not present in TE, which was applied as a biofertilizer in a lettuce crop and compared to mineral fertilization based on fresh matter and dry matter production. Lettuce production using TE was statistically equivalent to mineral fertilization. Toxic metals were not detected in the lettuce shoots. It was concluded that the anaerobically treated leachate from the composting company has the potential to be used as a biofertilizer. crops (UE (TE 8.2 82 8 2 (8.2 5.2 52 5 (5.2 1197 (119 L1 L 1 L-1 859 (85 L1. . demand solids 1743 (174 135 (13 Cd 0047 0 047 0.047 0206 206 0.20 0081 081 0.08 L1, 1, respectively Salmonella shoots 8. (8. 5. (5. 119 (11 L- 85 (8 174 (17 13 (1 004 04 0.04 020 20 0.2 008 08 0.0 (5 11 ( 17 00 02 0.

Abstract Environmental conditions have become a concern when involving the use of Geosynthetics clay liners (GCLs) as leachate barriers, particularly because they can be subjected to daily thermal cycles during construction and operation of landfills, which can affect their properties. This paper investigates the hydration behavior of a nonwoven geotextile carrier-GCL in contact with lateritic subsoils under isothermal and simulated thermal conditions as commonly found in tropical regions. A thermal insulate testing box was used to shelter an instrumented liner landfill allowing the investigation of thermal and hydraulic responses during hydration. Lateritic subsoils were observed not to provide high levels of GCLs hydration under isothermal conditions, whereas thermal daily cycles led to capillary break that restricted the moisture uptake at the interface between subsoil and the nonwoven geotextile carrier. Higher values of subsoil initial moisture contents were found to be significant to reduce capillary effects and to allow some GCL hydration. The poor hydration demonstrated to be critical in terms of GCL hydraulic behavior. (GCLs barriers landfills properties carrierGCL carrier regions

Abstract One of the most widespread applications of poly(lactic acid) (PLA) is as a raw material in the form of filaments for 3D printing. To improve final disposal alternatives and minimize their effects on the environment, the aim of this study is to determine the biodegradability of 3D-printed PLA waste composted in a landfill with leachate soil and garden soil for 90 days and 180 days. The soil characteristics and material properties were evaluated by laboratory analyses. Changes in soil chemical composition and the loss of microorganisms were recorded. The thermal and mechanical properties of PLA did not change significantly, but fungal colonies, encrustation, and changes in the original colour were found, indicating the onset of surface biodegradation of the samples. Controlled conditions or longer periods would be needed to maintain an ecosystem favourable to biodegradation; otherwise, PLA could accumulate in the environment, causing future pollution problems. polylactic poly lactic acid (PLA D printing environment 3Dprinted Dprinted printed 9 18 analyses recorded significantly colonies encrustation found samples otherwise problems 1

ABSTRACT Under stressful conditions, the use of high-vigor seeds is a relevant alternative to reduce losses, as they can germinate in a wide range of environmental conditions. However, it is necessary to understand the biochemical strategies adopted by high-vigor seeds to achieve better performance during periods of stress. Thus, the objectives of this research were to evaluate the tolerance of maize seeds of contrasting vigor subjected to different levels of stress due to accelerated aging and to verify whether differences in antioxidant metabolism and starch reduction explain the differences between vigor levels. The experiment was conducted with a high-vigor seed lot and a low-vigor seed lot, in a completely randomized design. The lots were subjected to 0, 24, 48, 60 and 72 hours of accelerated aging (45°C and 100% relative humidity), and after that the tests were carried out. The variables analyzed were the percentage of normal (first and second count) and abnormal seedlings, dead seeds, vigor index, electrical conductivity, total soluble sugars in the leachate, alpha-amylase activity, soluble sugar content, catalase activity, peroxide hydrogen, lipid peroxidation, proline, and carotenoid content. High-vigor seeds better tolerate stress conditions caused by high temperature and humidity. The higher content of total soluble sugars and alpha-amylase activity may explain the better performance of high-vigor seeds. highvigor losses However Thus lowvigor low design 0 24 48 6 7 45°C 45C C 45 100 humidity, humidity , humidity) out first count seedlings index conductivity leachate alphaamylase alpha amylase hydrogen peroxidation proline Highvigor High 2 4 10 1

ABSTRACT Entomopathogenic fungi (EP) and plant growth-promoting bacteria (GBP) in combination with liquid organic fertilizers can be the ecological alternative to complement chemical fertilization, and improve the nutrition and yield of melon (Cucumis melo L.). The objective of the study was to evaluate Metarhizium anisopliae, Beauveria bassiana and a consortium of BPCV (P. flurescens, B. subtilis, A. brasilence and B. mucilaginosus) in combination with vermicompost leachate (LVE) and goat manure biol (BEC). ) in the foliar nutritional concentration, plant growth, fruit size, yield and colonization of these microorganisms in the melon rhizosphere. An experimental design was used in complete randomized blocks, with six treatments (HE + LVE, BPCV + LVE, HE + BEC, BPCV + BEC, LVE and BEC) and a control. It was found that with the BPCV + BEC treatment, leaf N and Ca concentration increased by 9.4% and 21.3%, respectively, root dry weight by 45.8%, fruit polar diameter by 20.3% and fruit weight in 31.2% in relation to the control. While plants treated with HE + BEC and BPCV + BEC, compared to the control, increased leaf P concentration from 9.8 to 10.2%, stem diameter from 27.2% to 28.5% and yield from 12.4% to 12.6%. Both HE and BPCV colonized soil particles from the plant rhizosphere, which positively influenced melon yield. These results are beneficial for melon producers, both to increase crop yield and to complement chemical fertilization in an ecological way in the production system.

RESUMEN Los hongos entomopatógenos (HE) y las bacterias promotoras del crecimiento vegetal (BPCV) en combinación con abonos orgánicos líquidos puede ser la alternativa ecológica para complementar la fertilización química, y mejorar la nutrición y rendimiento de melón (Cucumis melo L.). El objetivo del estudio fue evaluar Metarhizium anisopliae, Beauveria bassiana y un consorcio de BPCV (P. flurescens, B. subtilis, A. brasilence y B. mucilaginosus) en combinación con lixiviado de vermicompost (LVE) y biol de estiércol de cabra (BEC) en la concentración nutrimental foliar, crecimiento de planta, tamaño de fruto, rendimiento y colonización de estos microorganismos en la rizosfera de melón. Se utilizó un diseño experimental en bloques completos al azar, con seis tratamientos (HE + LVE, BPCV + LVE, HE + BEC, BPCV + BEC, LVE y BEC) y un testigo. Se encontró que con el tratamiento BPCV + BEC aumentó la concentración de N y Ca foliar en 9,4% y 21,3%, respectivamente, peso seco de raíz en 45,8%, diámetro polar de fruto en 20,3% y peso de fruto en 31,2% en relación con el testigo. Mientras que las plantas tratadas con HE + BEC y BPCV + BEC, en comparación con el testigo, incrementaron la concentración de P foliar de 9,8 a 10,2%, diámetro de tallo de 27,2% a 28,5% y rendimiento de 12,4% a 12,6%. Tanto los HE y BPCV colonizaron partículas de suelo de la rizosfera de la planta, lo que influyó positivamente en el rendimiento de melón. Estos resultados son beneficiosos para los productores de melón, tanto para aumentar el rendimiento del cultivo como para complementar la fertilización química de manera ecológica en el sistema productivo.

Abstract: The objective of this study was to characterize the morphological composition of five populations of native maize and estimate their yields using agricultural practices without the use of agrochemicals. The study conducted in 2021, in the municipality of Cintalapa, Chiapas, within the experimental field of the Regional Academic Center of the Antonio Narro Autonomous Agrarian University. The five populations of native maize were provided by farmers from different regions of the state, with prior informed consent. The Agricultural practices consisted of using plant extracts and potassium soap with neem extract (Azadirachta indica) to prevent and combat pests. For fertilization, Californian red earthworm (Eisenia foetida) leachate and bat guano were applied in their commercial presentation. Morphological characters were evaluated with a descriptive statistical analysis considering days to male and female flowering, plant and ear height ear length and diameter, number of rows per ear and number of kernels per row. Grain yield was estimated by the weight of the ear harvested from a random sample of 20 plants per population. Numerical differences of the studied variables were identified, which demonstrates an existing genetic diversity. The populations with the highest yields were Campeón and Olotillo, with 5.37 and 4.4 ton ha-1 (± 1.24), respectively. The data provide information to design native maize conservation strategies through agrochemical-free management.

Resumen: El objetivo de este estudio fue caracterizar morfológicamente cinco poblaciones de maíz nativo y estimar sus rendimientos, empleando prácticas agrícolas sin uso de agroquímicos. El estudio se realizó en el año 2021, en el municipio de Cintalapa, Chiapas, dentro del campo experimental del Centro Académico Regional de la Universidad Autónoma Agraria Antonio Narro. Las cinco poblaciones de maíz nativo fueron proporcionadas por campesinos de diferentes regiones de la entidad, con previo consentimiento informado. Las prácticas agrícolas consistieron en uso de extractos vegetales y jabón potásico con extracto de neem (Azadirachta indica) para la prevención y combate de plagas. Para la fertilización se aplicó lixiviado de lombriz roja californiana (Eisenia foetida) y guano de murciélago en su presentación comercial. Los caracteres morfológicos se evaluaron con un análisis estadístico descriptivo considerando: días de floración masculina y femenina, alturas de planta y mazorca, longitud y diámetro de la mazorca, y número de hileras por mazorca y número de granos por hilera. El rendimiento de grano se estimó mediante el peso de la mazorca cosechada de una muestra aleatoria de 20 plantas por población. Se identificaron diferencias numéricas de las variables estudiadas, lo que demuestra una diversidad genética existente. Las poblaciones que presentaron mayores rendimientos fueron Campeón y Olotillo, con 5,37 y 4,4 ton ha-1 (± 1,24), respectivamente. Los datos aportan información para diseñar estrategias de conservación de maíces nativos con manejo libre de agroquímicos.

Summary: The continuous use of excessive nitrogenous fertilizers generates environmental risks by increasing nitrate accumulation, volatilization and leaching in soil, which causes losses and low efficiencies in the use of nitrogen (N). The objective of the present study is to evaluate the application of nitrogenous nanocomposites (NCN) as a slow-release fertilizer (SRF) in soil and its effect on growth of the lettuce crop. The NCN was prepared by sorption of a cationic surfactant on a bentonite clay. The study was performed in soil columns; the evaluated treatments were ratios of NCN and conventional fertilizer (FC) 25/0, 50/0, 75/0 and 100/0, 0/100, 25/75, 50/50 and 75/25. The variables evaluated were: fresh weight, dry biomass, leaf area, electrical conductivity, NO3- concentration in leachate and leaf, soil plant analysis development (SPAD) and normalized difference vegetation index (NDVI) units, as well as NCN release in deionized water. The results obtained indicate that the NCN treatments equaled the control after 40 days except for the 25/0 treatment that reduced the fresh weight variables by 20% and leaf area by 18% with respect to the 0/100 control. The SPAD and NVDI values did not have significant differences between treatments. The NCN/FC 0/100, 50/50 and 75/25 ratios increased nitrate concentration in leaves by 19%. The 100/0 treatment increased total dry biomass with 48%, 87% root volume and 73% root dry biomass. The results of the release in deionized water confirmed that NCN gradually releases nitrates and in higher amounts than those calculated. Finally, to conclude the nanocomposite material has the potential to be used as a slow-release fertilizer when growth increases. Therefore, nanocomposites could be an alternative to reduce the use of conventional fertilizers and nitrogen losses in soil.

Resumen: El uso continuo de fertilizantes nitrogenados en exceso genera riesgos ambientales al aumentar en el suelo la acumulación, volatilización y lixiviación de nitratos, que provocan pérdidas y baja eficiencia en la utilización de N. En este estudio, el objetivo fue evaluar la aplicación de nanocompuestos nitrogenados (NCN) como fertilizante de liberación lenta en el suelo y su efecto en el crecimiento del cultivo de lechuga. El NCN se preparó por la sorción de un surfactante catiónico en una arcilla de bentonita. El estudio se realizó en columnas de suelo, los tratamientos evaluados fueron relaciones de NCN y fertilizante convencional (FC) 25/0, 50/0, 75/0 y 100/0, 0/100, 25/75, 50/50 y 75/25. Las variables evaluadas fueron: peso fresco, biomasa seca, área foliar, conductividad eléctrica, concentración de NO3 - en lixiviado y hoja, unidades SPAD y NDVI, además de la liberación del NCN en agua desionizada. Los resultados obtenidos indican que después de 40 días los tratamientos con NCN igualaron al control excepto el tratamiento 25/0 que redujo las variables peso fresco 20% y el área foliar 18% con respecto al control 0/100. Los valores de SPAD y NVDI no tuvieron diferencias significativas entre tratamientos. Las relaciones NCN/FC 0/100, 50/50 y 75/25 aumentaron 19% la concentración de nitratos en hojas. El tratamiento 100/0 aumentó biomasa seca total con 48%, 87% el volumen radical y 73% la biomasa seca de raíz. Los resultados de la liberación en agua desionizada confirmaron que el NCN libera gradualmente nitratos y en mayor cantidad que lo calculado. Finalmente, se concluye que el material nanocompuesto tiene el potencial de usarse como fertilizante de lenta liberación al aumentar crecimiento, por lo que podría ser una alternativa para reducir el uso de fertilizantes convencionales y disminuir las pérdidas de nitrógeno en suelo.

Summary: Orange cultivation occurs mainly in the State of Veracruz. In Martínez de la Torre and San Rafael municipalities, two of the three most important orange juice producing companies operate in Mexico. The orange bagasse generated by each of these corporations ranges from 112 500 - 187 500 tons per production cycle. Managing large orange bagasse quantities is a major economic and environmental problem for this area of Veracruz. The juice producing companies in the area handle bagasse through heat treatments (dehydration for animal feed and combustion for heat generation). However, when the bagasse handling capacity exceeds, companies choose to deposit it in open dumping sites, posing a risk of contaminating soil, water and air due to biomass putrefaction and leachate generation. Therefore, the objective of this trial is to examine the orange bagasse management practices utilized by the juice producing companies installed in the central area of Veracruz. For this purpose, a literature review was performed together with an internship with one of these companies to collect first-hand data. All management strategies have economic-environmental advantages and disadvantages. Theoretically, the most sustainable alternative is the production and use of natural gas from the bagasse anaerobic digestion. Nevertheless, a life cycle assessment of bagasse management strategies should be performed to determine which alternative is the most appropriate based on economic profitability, environmental impact mitigation and energy efficiency.

Resumen: El cultivo de naranja se produce principalmente en el estado de Veracruz. En los municipios de Martínez de la Torre y San Rafael operan dos de las tres empresas productoras de jugo de naranja más importantes de México. La generación de bagazo de naranja por parte de cada una de estas corporaciones oscila entre 112 500 - 187 500 toneladas por ciclo productivo. El manejo de grandes cantidades de bagazo de naranja es un problema económico y ambiental importante para esta zona de Veracruz. Las empresas productoras de jugo de la zona manejan el bagazo a través de tratamientos térmicos (deshidratación para alimentación animal y combustión para la generación de calor). No obstante, cuando la capacidad de manejo del bagazo se ve rebasada, las empresas optan por depositarlo en tiraderos a cielo abierto. Esto representa un riesgo de contaminación para el suelo, el agua y el aire debido a la putrefacción de la biomasa y la generación de lixiviados. El objetivo de este ensayo fue examinar las prácticas de manejo de bagazo de naranja empleadas por parte de las empresas productoras de jugo instaladas en la zona centro de Veracruz. Para ello, se llevó a cabo una revisión de literatura aunado con una estancia de vinculación con una de estas empresas para recabar datos de primera mano. Todas las estrategias de manejo presentan ventajas y desventajas económico-ambientales. Teóricamente, la alternativa más sostenible es la producción y aprovechamiento de gas natural a partir de la digestión anaerobia del bagazo. No obstante, es recomendable realizar un análisis de ciclo de vida de las estrategias de manejo de bagazo con el propósito de determinar que alternativa es la más adecuada en función de la rentabilidad económica, mitigación del impacto ambiental y eficiencia energética.

RESUMEN Objetivo. En este estudio se evaluó la cinética de crecimiento de consorcios de microalgas marinas y de agua dulce en diferentes concentraciones de lixiviado extraído de un relleno sanitario. Materiales y métodos. Se realizó un diseño experimental por cada consorcio (marino Chlorella marina y Nannochloropsis oculata y de agua dulce Chlorella vulgaris y Ankistrodesmus falcatus) en concentraciones de lixiviado de 5, 10, 15% y un control (0%), con una inóculo principal y tres réplicas para cada concentración (K=4), en cultivo discontinuo. Resultados. Se encontraron diferencias significativas en el crecimiento microalgal a distintas concentraciones de lixiviado para los dos consorcios utilizados (H=12.9768; p<0.05 para microalgas marinas y H=20.0097; p<0.05 para microalgas dulceacuícolas), debido principalmente a un mayor crecimiento en el grupo control. También se encontró una correlación negativa significativa (p<0.01) entre la tasa de crecimiento y la división celular con la concentración de lixiviado, observándose un menor crecimiento en concentraciones superiores al 5% en ambos consorcios. Conclusiones. El consorcio marino logró generar mayor densidad celular, por lo que podría incrementar la efectividad de los procesos de biorremediación de contaminantes, a pesar del efecto negativo observado en mayores cantidades del compuesto.

ABSTRACT Objective. This study evaluated the growth kinetics of marine and freshwater microalgae consortia in different concentrations of leachate extracted from a landfill. Materials and methods. An experimental design was carried out for each consortium (marine Chlorella marina and Nannochloropsis oculata and freshwater Chlorella vulgaris and Ankistrodesmus falcatus) in leachate concentrations of 5, 10, 15% and a control (0%), with one main experiment and three replicates for each concentration (K=4), in batch culture. Results. Significant differences were found in the microalgal growth at different concentrations of leachate for both consortia (H=12.9768; p<0.05 for marine microalgae and H=20.0097; p<0.05 for freshwater microalgae), attributed to a higher growth in the control sample. A significant negative correlation (p<0.01) was also found between leachate concentration and both growth rate and cell division. A lower growth was observed at concentrations above 5% in both consortia. Conclusions. The marine consortium was able to generate a higher cell density, which may increase the effectiveness of the pollutant bioremediation process, despite the negative effect observed at higher amounts of the compound.

The use of microalgae cultures to process effluents from industries, leachates, and tanneries, among others, quantified by the reduction of metallic materials in the medium and the reduction of chemical oxygen demand (COD), helps reduce the environmental impact caused by human development. In addition, with the growth of the culture, it is possible to produce a significant amount of chlorophyll, a carotenoid of high value in the cosmetics and food industries that are used as a natural pigment. In this context, this work presents a study conducted to verify the bioremediation and chlorophyll production potential of the cultivation of the microalgae Chlorella minutíssima, using the Taguchi method. The microalgae Chlorella minutissima has given good results in the bioremediation of leachate, as a mean reduction of 33% in COD was obtained, as well as a 92% reduction in the toxic components. In addition, statistical analysis revealed that the four process factors were significant factors for chlorophyll a, chlorophyll b and carotenoid productivity (p < 0.05). Finally, it was observed that the maximum chlorophyll a (111.9 ± 0.8 mg-L-1-d-1), chlorophyll b (66.1 ± 1.7 mg-L-1-d-1), and carotenoid (31.9 ± 0.03 mg-L-1-d-1) values obtained occurred in Experiment 8, which is closer to the ideal conditions identified by statistical analysis, revealing the effectiveness of the use of the Taguchi method for the design of experiments.

Ceramic ware is used around the world, usually daily. In the past, lead was used in the glazes and decorative paints applied to ceramic ware, mainly to increase durability, impart a smooth, glasslike finish to glazes and intensify decorative pigments. However, this use of lead at times contributed to lead exposure and poisoning. While measures have been put in place to limit the use of lead in ceramic ware in well-resourced countries, there is relatively little information on the situation in poorly resourced settings. In the current preliminary South African study, we assessed the lead content and leaching rates from newly purchased ceramic ware. The majority of the 44 ceramic ware items had lead levels > 90 ppm. Elevated lead concentrations were found in the leachate from only one item. The findings indicate a need for further research on the potential for lead exposure from ceramic wares, and support calls for increased attention to the many potential sources of lead exposure in poorly resourced settings. SIGNIFICANCE: • The study reveals the potential for lead contamination of certain types of ceramic ware available in South Africa. • Daily use of lead-contaminated ceramic ware may increase the risk of lead exposure, especially among the poorest. • The study findings are indicative of a need for further research to fully characterise the extent of lead in ceramic ware.

Arsenic-bearing acidic effluent from hydrometallurgical processes contains many harmful metal ions and must be appropriately treated before discharge. In the present study, arsenic, copper, zinc, aluminum, and magnesium were co-precipitated by means of the Fenton reaction. The precipitates obtained under different conditions were investigated to determine their stability. The results indicate that pH value and hydrogen peroxide (H2O2) dosage have significant effects on the removal of various elements. Arsenic, copper, zinc, and aluminum (but not magnesium) can be removed at pH 5-6 and anH2O2/As mole ratio of 2 at ambient temperature. The precipitates were mainly amorphous and granular with particle size in the micrometre range. The arsenic concentration in leachate from the toxicity characteristic leaching test was 3.6 mg/L, which proves that the precipitates are effective in fixing arsenic.