Introduction: Constructed wetlands (CWs) have been widely used in domestic wastewater treatment, and plants are the main component in pollutant removal.
Objective: To evaluate the efficiency of Sagittaria latifolia and Sagittaria lancifolia in the removal of basic pollutants in nine free flow constructed wetlands (FFCWs).
Methodology: Nine FFCWs were established, three without vegetation (FFCW-Control), three with Sagittaria lancifolia (FFCW-S-Lan) and three with Sagittaria latifolia (FFCW-S-Lat); for each of them, temperature, pH, total suspended solids (TSS), biochemical oxygen demand (BOD₅), chemical oxygen demand (COD), fecal coliforms (FCs), and bacterial and plant biomass were determined.
Results: Sagittaria latifolia presented 21.4 ± 1.90 mg∙L^-1 of TSS, 14.6 ± 4.44 mg∙L^-1 of BOD₅, 29.55 ± 10.80 mg∙L^-1 of COD and 1 000 MPN∙100 mL^-1 of FCs, while Sagittaria lancifolia had 12.6 ± 3.80 mg∙L^-1 of TSS, 24.4 ± 2.09 mg∙L^-1 of BOD₅, 59.62 ± 5.87 mg∙L^-1 of COD and 100 MPN∙100 mL^-1 of FCs. The removal efficiency of Sagittaria latifolia in TSS, BOD₅, COD and FCs was 94, 97, 96 and 99 %, respectively, while for Sagittaria lancifolia it was 97, 94, 93 and 99.9 %, respectively.
Study limitations: The behavior of Sagittaria latitolia and Sagittaria lancifolia within the CWs is documented for only one year, whereas it is known that most of the macrophytes used reach their maximum pollutant removal efficiency between two and three years.
Originality: There are few reports on the ability of Sagittaria latitolia and Sagittaria lancifolia to remove basic pollutants when used in a CW as a primary or secondary treatment.
Conclusions: The treated water meets the discharge criteria of NOM-001-SEMARNAT-1996 and NOM-003-SEMARNAT-1997, and can be reused for other purposes.
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Introduction: Biosynthesis has emerged as an option for obtaining nanometric materials due to the need to use more environmentally-friendly synthesis methods.
Objective: To synthesize silver nanoparticles (Ag NPs) with aqueous Crataegus gracilior Phipps (tejocote) bark extract as precursor.
Methodology: Ag NPs were synthesized with AgNO₃ and aqueous Crataegus gracilior bark extracts, and later characterized by ultraviolet-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and X-ray diffraction (XRD). In addition, their size distribution and zeta potential were obtained.
Results: The presence of Ag NPs reached maximum values at concentrations of 10 % (w/v). Mostly spherical nanoparticles were found in the range of 20 to 50 nm in size. FTIR confirmed the stabilization of the nanoparticles through their interactions with functional groups of carbohydrates and proteins. XRD and TEM results were explained by their face-centered cubic (FCC) structure with a size of 26 nm, a mean hydrodynamic diameter of 108 nm and polydispersity index of 0.24. The zeta potential values in the dispersions were -21.9 ± 5.11 mV, denoting colloidal stability.
Limitations of the study: The characteristics of the nanoparticles obtained are only valid under the following synthesis conditions: 10 % (w/v) solids and pH 10.
Originality: A non-reported plant material was used, capable of acting as a reducing and passivating agent of silver nanoparticles.
Conclusions: Biosynthesis of Ag NPs with tejocote extract is an efficient, low-cost and environmentally-friendly method.

Introduction: The quality of potato tubers is influenced by a group of physical and chemical attributes which define their end-use.
Objective: To evaluate the effect of the genotype-environment interaction on the physicochemical characteristics of potato tubers and chips.
Methodology: Four genotypes (Fianna, Nau, 5-10, and 99-39) were grown in two locations (Metepec and Raíces) and two consecutive years (2012 ad 2013). Internal browning, specific gravity (SG), starch, sugars and phenols were evaluated in tubers, then their effect on chip yield, color and texture was assessed.
Results: Tubers with higher SG, dry matter, and starch, as well as lower reducing sugars and phenolic content, were produced in Raíces. These characteristics led to a high yield of potato chips with acceptable color and texture. In contrast, zebra chip (ZC) symptoms were observed in tubers grown at lower altitude, at higher temperatures, and at lower precipitation, negatively affecting potato chip quality.
Study limitations: We hypothesized that the higher altitude and lower temperatures would avoid the prevalence of symptoms of the ZC; however, monitoring of insect vectors and infection by PCR is needed.
Originality: This is the first study about genotype-environment interaction on end-use tuber quality carried out under experimental conditions where ZC incidence is present.
Conclusions: Clone 5-10, grown at higher altitudes, can produce tuber with good attributes for processing into chips, French fries, and fresh consumption.