Presence Of Water Sources Research Articles

Application of AHP in defining suitable locations for the construction of forest roads in protected areas: A case study of Fruska Gora

The construction of forest roads is considered to be one of the most pronounced anthropogenic impacts on the environment in the forests of national parks. In order to reduce the negative impacts of forest roads on the environment, the planning of a multifunctional network of forest roads must be approached systematically, taking into account a number of aspects. In recent years, a large number of methods have been developed to reach a final solution based on a multitude of criteria, with a particular emphasis on multi-criteria analysis (MCA) in combination with a geographic information system (GIS). This paper presents the possibility of applying the Analytical Hierarchy Process (AHP) in combination with GIS, in order to select suitable locations for the construction of forest roads in the ?Fruska gora? National park. The decision maker evaluated 6 selected criteria to determine the suitability of locations, where ?the presence of water sources? and ?the risk of fire? were identified as the criteria with the greatest impact on the suit?ability of locations, while the ?annual cut? criterion had the least impact.

Dynamic and Seasonal Distribution of Enteric Viruses in Surface and Well Water in Riyadh (Saudi Arabia).

Enteric viruses are the major cause of gastroenteritis and enteric hepatitis worldwide, but in some areas like Saudi Arabia, little is known about their presence in water sources. The available information from clinical samples is not enough to figure out their actual prevalence. The aim of this study was to gather information for the first time in Saudi Arabia on the presence of the Norovirus (NoV) genogroup GI and GII, hepatitis A virus (HAV), and hepatitis E virus (HEV) in water. For this purpose, thirteen monthly samples were collected from Lake Wadi Hanifa and surrounding wells from December 2014 to November 2015. Viruses were detected and quantified using real-time RT-qPCR. Despite HEV findings being anecdotic, our results highlight interesting behaviors of the other viruses. There was a higher prevalence of noroviruses in Wadi Hanifa samples than in well water samples (46.43% vs. 12.5% of NoV GI; 66.67% vs. 8.33% of NoV GII). On the contrary, similar levels of HAV positivity were observed (40.48% in surface water vs. 43.06% in well water). Also, a strong influence of flooding events on HAV and NoV GI occurrence was observed in both surface and well water samples, with NoV GII apparently not affected.

Study of heavy metal resistance genes in Escherichia coli isolates from a marine ecosystem with a history of environmental pollution (arsenic, cadmium, copper, and mercury).

We analyzed whole genome sequences of 308 Escherichia coli isolates from a marine ecosystem to determine the prevalence and relationships of heavy metal resistance genes (HMRGs) and antibiotic resistance genes (ARGs), as well as the presence of plasmid sequences. We screened all genomes for presence of 18 functional HMRGs conferring resistance to arsenic, cadmium, copper, or cadmium/mercury. In subset analyses, we examined geographic variations of HMRG carriage patterns in 224 isolates from water sources, and sought genetic linkages between HMRGs and ARGs in 25 genomes of isolates resistant to antibiotics. We found high carriage rates of HMRGs in all genomes, with 100% carrying at least one copy of 11 out of 18 HMRGs. A total of 173 (56%) of the isolates carried both HMRGs and plasmid sequences. In the 25 genomes of antibiotic-resistant isolates, 80% (n = 20) carried HMRGs, ARGs, and plasmid sequences, while 40% (n = 10) had linked HMRGs and ARGs on their assembled genomes. We found no evidence of geographic variation in HMRG frequency, nor any association between locational proximity to Superfund sites and co-carriage of HMRGs and ARGs. Our study findings indicate that HMRGs are common among E. coli in marine ecosystems, suggesting widespread heavy metal presence in water sources of a region with history of environmental pollution. Further research is needed to determine the role HMRGs play in driving antimicrobial resistance in human pathogens through genetic linkage and the value their detection in environmental bacterial genomes may offer as an indicator of environmental heavy metal pollution.

Tailoring porous organic polymers with enhanced capacity, thermal stability and surface area for perfluorooctane sulfonic acid (PFOS) elimination from water environment

Perfluorooctane sulfonic acid (PFOS), a perfluoroalkyl substance, has engendered alarm over its presence in water sources due to its intrinsic toxicity. Hence, there is a pressing need to identify efficacious adsorbents capable of removing PFAS derivatives from water. To achieve this, batch adsorption studies under various circumstances were employed to tune amorphous polymer networks regarding their morphological configuration, heat durability, surface area and capacity to adsorb PFOS in water. A facile, one-pot nucleophilic substitution reaction was employed to synthesize amorphous polymer networks using triazine derivatives as building units for monomers. Notably, POP-3 exhibited a superlative adsorption capacity, with a removal efficiency of 97.8%, compared to 90.3% for POP-7. POP-7 exhibited a higher specific surface area (SBET) of 232 m2 g−1 compared to POP-3 with a surface area of 5.2 m2 g−1. Additionally, the study emphasizes the importance of electrostatic forces in PFOS adsorption, with pH being a significant element, as seen by changes in the PFOS sorption process by both polymeric networks under neutral, basic and acidic environments. The optimal pH value for the PFOS removal process using both polymers was found to be 4. Also, POP-7 exhibited a better thermal stability performance (300 °C) compared to POP-3 (190 °C). Finally, these findings indicate the ease with which amorphous polymeric frameworks may be synthesized as robust and effective adsorbents for the elimination of PFOS from waterbodies.

Statistical Modelling of Biosorptive Removal of Hexavalent Chromium Using Dry Raw Biomasses of Dioscorea rotundata, Elaeis guineensis, Manihot esculenta, Theobroma cacao and Zea mays

Hexavalent chromium [Cr (VI)] is a highly toxic and hazardous contaminant that poses serious health risks to both humans and the environment. Its presence in water sources can lead to severe health issues, including various types of cancer and respiratory ailments. Therefore, developing efficient and effective methods for Cr (VI) removal is crucial in ensuring safe and clean water supplies. The aim of this research is the environmentally responsible elimination of hexavalent chromium by bioadsorption using corn residues (CR), palm fiber (PF), and the peels of yam (YP), cassava (CP), and cocoa (CH). The study was conducted with varying levels of pH, bioadsorbent quantity, temperature, and adsorbent particle size at 200 rpm, with an initial concentration of 100 mg/L and 24 h of contact time to improve the adsorption efficiency. The process variables were evaluated and optimized using the statistical technique response surface methodology (RSM). The SEM-EDS analysis revealed that the predominant elements in the structure of the bioadsorbents were carbon and oxygen. Furthermore, the adsorption process led to the incorporation of Cr (VI) into the structure of the biomaterials, as indicated by their EDS spectra. The maximal adsorption efficiency of 99.11% was obtained at pH 2, bioadsorbent dose of 0.03 mg, 30 °C, and 0.5 mm of particle size. Various equilibrium isotherms were utilized to fit and analyze the adsorption data. The assessed maximum adsorption capacities were 38.84, 56.88, 52.82, 138.94, and 240,948.7 mg/g for YP, PF, CP, CH, and CR, respectively. The adsorption data exhibited conformity with the Freundlich and Redlich–Peterson isotherm models (R2 = 0.95), indicating that the phenomenon occurs in a multilayer. Pseudo-second order and Elovich kinetic models adjusted the kinetics of chromium (VI), suggesting that the mechanism could be controlled by chemisorption. Therefore, the residual biomasses evaluated can serve as a cost-effective adsorbent for Cr (VI) removal, and the use of RSM enables efficient modeling and prediction of the adsorption process.

An Overview of the Impact of Pharmaceuticals on Aquatic Microbial Communities.

Pharmaceuticals are present as pollutants in several ecosystems worldwide. Despite the reduced concentrations at which they are detected, their negative impact on natural biota constitutes a global concern. The consequences of pharmaceuticals' presence in water sources and food have been evaluated with a higher detail for human health. However, although most of the pharmaceuticals detected in the environment had not been designed to act against microorganisms, it is of utmost importance to understand their impact on the environmental native microbiota. Microbial communities can suffer serious consequences from the presence of pharmaceuticals as pollutants in the environment, which may directly impact public health and ecosystem equilibrium. Among this class of pollutants, the ones that have been studied in more detail are antibiotics. This work aims to provide an overview of the impacts of different pharmaceuticals on environmental biofilms, more specifically in biofilms from aquatic ecosystems and engineered water systems. The alterations caused in the biofilm function and characteristics, as well as bacteria antimicrobial tolerance and consequently the associated risks for public health, are also reviewed. Despite the information already available on this topic, the need for additional data urges the assessment of emerging pollutants on microbial communities and the potential public health impacts.

Electrochemical sensing platform for the detection of nitroaromatics using g-C3N4/V2O5 nanocomposites modified glassy carbon electrode

Rapid, reliable, cost-effective and trace-level detection of nitroaromatic toxins is becoming increasingly important because of their carcinogenic nature, and their presence in water sources as an environmental contaminant. The present study reports the development of an electrochemical sensing platform based on g-C3N4/V2O5 (VOCN) nanocomposites modified glassy carbon electrode (GCE) for the effective detection of nitroaromatics. The VOCN nanocomposites were synthesized via wet impregnation method, and were characterized by XRD, FT-IR, HRSEM and XPS techniques. The electrochemical behavior of four nitroaromatics (4-NP, DNP, DNT and TNP) were investigated on seven nanomaterials-based sensors using cyclic voltammetry, square wave voltammetry and chronoamperometry techniques. Under optimized conditions, the nitroaromatic compounds exhibited reduction peaks corresponding to the number of nitro-functional groups on an aromatic ring. The electrochemical studies revealed that the composite with 7 wt% V2O5 (VOCN7/GCE) exhibits higher sensitivity for the detection of 4-NP, DNP, DNT and TNP. The VOCN7/GCE recorded the limit of detection (LOD) as low as 0.85 nM, 3.3 nM, 3.4 nM and 11.0 nM in a linear range between 1.0 nM - 100.0 µM, 10.0 nM - 100.0 µM, 10.0 nM - 100.0 µM and 30.0 nM - 100.0 µM for 4-NP, DNP, DNT and TNP, respectively. The fabricated sensor showed high reusability and reproducibility, and could detect the four nitroaromatics in real water samples.

Coxiella Burnetii in Horses of Algeria: Seroprevalence and Associated Risk Factors

The Q fever is a worldwide zoonotic disease caused by Coxiella burnetii (an obligate intracellular bacterium). This pathogen affects humans, ruminants, equines, carnivores, rodents, and birds. A cross-sectional study was carried out from March 2017 to May 2018 to assess the seroprevalence and identify the risk factors of C. burnetii infection in horses (Equus Caballus) residing in three districts of Algerian, namely Tiaret, El-Bayadh, and Ghardaia. Serum samples collected from 182 horses were analyzed via enzyme-linked immunosorbent assay (ELISA). Association of seropositivity with potential risk factors related to animals (e.g., age, gender, breed, housing, and presence of ticks), breeding characteristics (e.g., geographical localization, contact with animals), and environmental characteristics (i.e., presence of water source) was analyzed by univariate and multivariate logistic regression. An overall seroprevalence of 9.9% (18/182) was obtained. The univariate analysis of risk factors for C. burnetii seroprevalence demonstrated higher seropositivity in horses that had contact with small ruminants (p=0.004) and dromedaries (p=0.002) as well as in those living near a water source (p=0.036) and in El-Bayadh district (p=0.005). The multivariate logistic regression analysis indicated that the risk of C. burnetii infection was significantly higher in horses that were in contact with small ruminants (RR: 15.6). Algeria is endemic for Q fever in horses and prophylactic measures must be taken to reduce /prevent its transmission to animals and humans.

Strategizing of vanguard physicochemical and biological technologies for water treatment in Kuzbass (technological aspect)

The authors use Kuzbass as the example to study strategic approach and methodology of choosing and implementing vanguard (perspective) physicochemical and biological technologies for water treatment plants. They also examine the requirements for purification and disinfection of drinking and waste waters under present conditions characterized by increased anthropogenic loads. These procedures should be carried out with controlling a number of new types of dangerous contaminants. Currently there is no provision for systematic analysis of their presence in water sources before and after their treatment. The authors study the interrelation between forecasting, strategizing, target programming, project management of planning and realization of the priority of implementation of vanguard physicochemical and biological technologies of vanguard physicochemical and biological technologies for water treatment at the water supply and drainage utilities. In the strategic study the authors adduce the overview of perspective trends of development of vanguard physicochemical and biological technologies and the examples of their technical realization which allow fulfilling the strategy’s priority under study within the set of priorities “Development strategy of life supply systems (water supply and water waste). Water utilities as “green economy” translators”. The article studies the levels of water quality control as well as common approaches to building regional water quality control centres and implementing online water quality control. The authors adduce the main competitive advantages that the Kemerovo region possesses to fulfill the priority. Strategizing of the implementation of vanguard physicochemical and biological technologies will provide the opportunity for realizing long-term (up to 15 years long) target programs in water supply and drainage areas in order to improve the performance of water industry.

DIVERSITY AND SEASONALITY OF BIRDS IN PERMANENT WATERHOLES IN THE PERUVIAN NORTHWEST

In arid environments, the presence of water sources is key for biological communities as they provide a vital element that is scarce. In this study, we evaluated the diversity and the relative abundance of bird species in seven permanent waterholes, located along an elevational gradient in mountain dry forests in northwestern Peru. From January to December 2016, we analyzed 114,438 photos (22,888 photo events) obtained through camera traps, and counted bird species and individuals photographed at these waterholes. We measured how bird diversity and abundance varied between waterholes during the humid (January to May) and dry (June to December) seasons. In total, we made 4,137 detections of 35 bird species. Among these, 10 species were endemic to the Tumbesian area, including one that is glob- ally endangered (the White-Winged Guan, Penelope albipennis). 95% of detections in all waterholes corresponded to four species of pigeons/ doves (Columbidae). We also recorded two migratory species, including one that is uncommon in northwestern Peru (the Slaty Thrush, Tur- dus nigriceps). The number of bird detections during the dry season was almost two times higher than that during the humid season. We did not find any correlations between relative abundance/diversity at waterholes and elevation or distance to agricultural areas. We postulate that permanent waterholes are a key to bird species in the northwestern Peruvian dry forests and should be protected, since they provide a scarce resource to several range-restricted species, including one that is globally threatened.

Karakterisasi Tanah Salin di Wilayah Pesisir Kecamatan Banda Mulia Kabupaten Aceh Tamiang

Abstract. Coastal land located in the District of Kota Mulia directly adjacent to the sea is thought to have suffered salinization due to the tide. Indicated by the presence of water sources (such as wells, and wells drilled) were salted and morphological disruption of plants that grow in the region. The purpose of this study was to determine the morphological characteristics, physical and chemical soil saline and memetakanya with quantitative descriptive method based on field observations and laboratory analyzes. Salinity measurement results based on the value of electrical conductivity (EC) of land in this area has five criteria, namely non copy, the copy is very low, slightly saline and highly saline. Land categorized the copy is a criterion rather copy, copy and highly saline, with a base element that dominates is Na and Mg. Saline soils in this region has a highly acidic pH, SAR values of tranquility and saturation Na generally 15%.Characterization of Salin in the Coastal Region of Banda Mulia District, Aceh Tamiang RegencyAbstract. The coastal land located in the Banda Mulia Subdistrict which is directly adjacent to the sea is thought to have undergone salinization due to tides. Indicated by the presence of salty water sources (such as wells and drilled wells) and the morphological disturbance of plants growing in the region. The purpose of this study was to determine the morphological, physical and chemical characteristics of saline soil and map it with quantitative descriptive methods based on field observations and laboratory analysis. Salinity measurement results based on the value of Electrical Conductivity (EC) of lands in this region have five criteria, namely non-saline, very low saline, near saline and very saline. Saline is categorized as a rather saline, saline and very saline, with the basic elements dominating are Na and Mg. Saline soils in this region have very acidic pH, low SAR value and Na saturation in general 15%.

Contamination of wastewater with Echinococcus multilocularis – possible implications for drinking water resources in the QTP China

Echinococcus multilocularis is a parasite that causes a dangerous zoonosis, alveolar echinococcosis (AE). Its presence in water sources, however, has scarcely been studied heretofore. Accordingly, 222 samples of different origin including wastewater from wastewater treatment plants (WWTPs) (n = 137), slaughterhouse (n = 49) as well as water from rivers (n = 26) and a cattle farm (n = 10) were collected from Xining City and a rural area in Qinghai-Tibet Plateau (QTP), an endemic area. Material obtained after processing of 10 L volume samples was subsequently analysed using three molecular detection methods: nested PCR, real-time PCR and LAMP. E. multilocularis DNA was found in 13 (5.85%) water samples; including 8 (5.8%), 3 (6%), 2 (20%) and 0 positive samples found in WWTPs, a slaughterhouse, a cattle farm and rivers, respectively. All three (LAMP, PCR, RT-PCR) molecular tools displayed high agreement and effectiveness in their ability of detecting the parasite’s DNA in environmental material. This is the first investigation describing E. multilocularis detection in wastewater samples, using three sensitive molecular diagnostic tools. Results indicate the role of wastewater in dissemination of E. multilocularis and the risk of contamination of water sources.

PH values and presence of Escherichia coli in human water supply in an area of intense swine activity

Intensive swine activity in Santa Catarina presents itself as an environmental problem related to the management of the manure generated by this activity. Thus, it is usual to apply the waste in agricultural areas near the units of production of pigs, however, this practice when carried out without technical recommendation can cause soil and water sources pollution and/or contamination. The aim of this study was to evaluate the pH values and E. coli presence in water sources in a region with intense swine activity in the State of Santa Catarina. Lentic and lotic water sources were evaluated in four rural properties and in the Coruja River, in the watershed of Coruja/Bonito River, in the municipality of Braço do Norte/SC, being that the pH values in water and the presence and quantification of thermotolerant coliforms, represented by the bacteria Escherichia coli, throught CONOMA resolution nº357/2005. The pH values were below the minimum limit established by the legislation and, for the bacteriological evaluation, the study points were below the limit established by the legislation also. However, the presence of these microrganisms indicates the constant arrival of material of enteric origin.

Payment for ecosystem services programs in the Brazilian Atlantic Forest: Effective but not enough

Payment for ecosystem services (PES) are economic incentives intended to generate conservation benefits, principally on private properties. The global portfolio of PES programs is estimated to represent an annual investment of more than USD $36 billion. Despite this substantial investment, the continued lack of systematic and rigorous impact evaluation of PES has contributed to uncertainty regarding the effectiveness of this tool for conservation. Here, we assessed the ability of two watershed PES programs to promote native forest conservation in the Brazilian Atlantic Forest. Those two focal programs are among the most well-established PES programs in Brazil, and form part of a larger network of PES programs intended to protect the drinking water supply of over 19 million people in the São Paulo metropolitan region. Using a counterfactual approach, we examined if enrollment in a PES program contributed to the conservation of on-farm native forest cover. With propensity score matching, we identified a set of neighboring, non-enrolled ‘control’ properties, with similar size, altitude, soil type, demographic density, presence of water sources and forest cover. We then estimated forest cover on enrolled and control properties before and after PES implementation with a differences-in-differences method, modeled as the probability of an observed change in on-farm forest area as a consequence of PES enrollment. We found that PES has a positive effect on forest cover, with PES enrollment over a five-year period associated with an additional 2.8–5.6% of farm area coverage in native Atlantic Forest, through forest regeneration. PES enrollment was associated with a non-significant trend toward decreased loss of vegetation. We discuss the implications of these results for understanding the contribution of PES to additionality in forest conservation. While positive, the relatively slow impact of PES on forest regeneration suggests that environmental managers should not count exclusively on PES mechanism to achieve conservation goals.

Ubiquitous exposure to microfiber pollution in the air

Microplastics (MPs) are among major micro-pollutants ( $ < 5 $ mm) which can be found in water sources and air in substantial quantities, and which still are not covered by standard extraction and analysis procedures. Even though several researches have demonstrated the presence in water sources of different MP fragments, the most common type of MP in wastewater treatment plants (WWTPs) and in the atmosphere are MP fibers. MP fibers (MFs) present in the atmosphere deriving from a number of sources can settle on the ground, but they can also float due to wind and air flows, reaching the respiratory system of humans like other pollutants. The objective of the present study is to make an evaluation of the amount of microplastic fibers that freely float in the air due to their light weight and nano-, micro-size. To quantify the presence of MPs in the air, their amount was evaluated after collecting them in two sites: an intercity terminal and a university campus.

Seroprevalence of Coxiella burnetii infection (Q fever) in sheep farms located in Sicily (Southern Italy) and related risk factors

Q fever is an important and widespread zoonotic disease caused by the bacterium Coxiella burnetii, which has been recently reclassified as belonging to the order Legionellales. Q fever in humans is considered an endemic, mostly occupational, disease in several Mediterranean Countries.The infection is often asymptomatic in ruminants but infected animals excrete the bacteria into the environment, mainly during and after parturition or abortion.The aim of this study was to estimate the seroprevalence of C. burnetii infection and related risk factors in Sicilian ovine farms. A total of 6641 serum samples, from sheep belonging to 205 flocks, were examined by Enzyme Linked ImmunoSorbent Assay (ELISA).The seroprevalence at the animal level was 18% (95% CI), while at farm level it was 73.6% (95% CI).Moreover, an evaluation of potential risk factors was carried out on farms, including: farm size, contact with other animals, production type, farm localization and presence of water sources. The multivariate analysis indicated only two factors significantly associated with C. burnetii seropositivity: flock size (χ2 = 10.82; p < 0.0010) and altitude of the farm (χ2 = 4.28; p < 0.0386).These findings represent a first piece of information on Coxiella burnetii circulation in the examined areas. There is actually no specific vaccination plan to reduce the infection prevalence in animals; therefore, a better knowledge on the pathogen spreading could be helpful to take adequate preventive measures, especially considering the potential consequences and risks for human public health too.

An assessment of human-elephant conflict and associated ecological and demographic factors in Nilambur, Western Ghats of Kerala, southern India

Elephant conservation carries cost in the form of human-elephant conflict and affects the wellbeing of people living near ecologically important areas. Conflicts impart serious challenges towards the survival of Asian Elephants, which are categorized as Endangered in the IUCN Red List of Threatened Species. Issues of wildlife conservation are least addressed in areas with less restricted categories of protection. Hence an attempt was made to evaluate the intensity of elephant conflict and factors associated with its occurrence in villages with forest fringes of North and South Forest Divisions of Nilambur, Kerala, southern India. It was hypothesized that variables such as number of houses, area of village, livestock population, forest frontage, and presence of water source along the forest boundary abutting the village to be the underlying correlates of conflict. Field studies were conducted fortnightly from June 2014 to May 2015, by visiting farms and households of 17 selected forest fringe villages. Observational methods, questionnaire surveys and secondary data collection were employed for this purpose. A total of 277 incidents of crop depredation, 12 incidents of property damage, three human injuries, and one human death due to conflict were recorded during this period. Crop raiding was highest during post monsoon season and it was low during pre-monsoon and monsoon seasons. Multiple linear regression results suggest that forest frontage and livestock population were significant predictors of conflict incidence. Information regarding the prime causes of conflict will be helpful for planning strategies for the establishment of appropriate mitigation methods. The present study serves as baseline information which will be helpful for formulating prospective management plans.

Virulence determinants and production of extracellular enzymes in Enterococcus spp. from surface water sources.

Virulence factors in Enterococcus may be indicative of potential pathogenicity. The aim of this study was to determine the relationship between the presence of clinically relevant virulence genes, in Enterococcus spp. from environmental water, and their in vitro expression. One hundred and twenty-four Enterococcus isolates (seven species), from five surface water systems in the North West Province, South Africa, were screened for the presence of asa1, cylA, esp, gelE and hyl using polymerase chain reaction. The expression of cylA, hyl and gelE was determined by phenotypic assessments. Sixty-five percent of the isolates were positive for one virulence gene and 13% for two or more. Most frequently detected genes were gelE (32%) and cylA (28%). Enterococcal surface protein was absent in all isolates screened. The presence of virulence genes was correlated with their extracellular enzyme production. The results show that a large percentage of these environmental Enterococcus spp. possess virulence factors that could be expressed in vitro. This is a cause for concern and could have implications for individuals using this water for recreational and cultural purposes. Further investigation is required into the sources of these potential pathogenic Enterococcus isolates and measures to minimize their presence in water sources.

Diseño de un esquema de compensación por servicios ambientales para la cuenca del río Meléndez en el Municipio de Santiago de Cali, Colombia

La compensación por servicios ambientales –CSAH se utilizó como herramienta para solucionar o mitigar las variaciones de los caudales del río Meléndez, ocasionadas por el deterioro de la cobertura boscosa en la parte alta y media de la cuenca. El objetivo del estudio fue desarrollar una fórmula para definir el valor a compensar a los propietarios y poseedores de zonas de interés, en función de los atributos y características ambientales de los predios. Mediante la aplicación de una fórmula matemática se determinó el valor a compensar por los servicios ambientales por hectárea, a partir de la estimación de un precio base y en función de las condiciones ideales de los predios, para garantizar la regulación hídrica: a) presencia de quebradas, b) existencia de franja de protección, c) presencia de fuentes de agua, d) condiciones del suelo, e) sistemas productivos. El valor a compensar por año se encuentra entre un mínimo de $367.748 y un máximo de $735.496 (precios de 2015), que equivale al costo de oportunidad estimado en función de los cuatro principales cultivos en la parte alta y media de la cuenca. Estos resultados enfatizan la viabilidad de hacer de la compensación por servicios ambientales, un ejercicio que garantice la conservación de las cuencas que abastecen de agua a la población, aguas abajo.

Electrochemical advanced oxidation for cold incineration of the pharmaceutical ranitidine: Mineralization pathway and toxicity evolution

Ranitidine (RNTD) is a widely prescribed histamine H2-receptor antagonist whose unambiguous presence in water sources appointed it as an emerging pollutant. Here, the degradation of 0.1mM of this drug in aqueous medium was studied by electrochemical advanced oxidation processes (EAOPs) like anodic oxidation with electrogenerated H2O2 and electro-Fenton using Pt/carbon-felt, BDD/carbon-felt and DSA-Ti/RuO2–IrO2/carbon-felt cells. The higher oxidation power of the electro-Fenton process using a BDD anode was demonstrated. The oxidative degradation of RNTD by the electrochemically generated OH radicals obeyed a pseudo-first order kinetics. The absolute rate constant for its hydroxylation reaction was 3.39×109M−1s−1 as determined by the competition kinetics method. Almost complete mineralization of the RNTN solution was reached by using a BDD anode in both anodic oxidation with electrogenerated H2O2 and electro-Fenton processes. Up to 11cyclic intermediates with furan moiety were detected from the degradation of RNTD, which were afterwards oxidized to short-chain carboxylic acids before their mineralization to CO2 and inorganic ions such as NH4+, NO3− and SO42−. Based on identified products, a plausible reaction pathway was proposed for RNTD mineralization. Toxicity assessment by the Microtox® method revealed that some cyclic intermediates are more toxic than the parent molecule. Toxicity was quickly removed following the almost total mineralization of the treated solution. Overall results confirm the effectiveness of EAOPs for the efficient removal of RNTD and its oxidation by-products from water.