Microplastics in a tropical Andean Glacier: A transportation process across the Amazon basin?

Microplastic (MPs) contamination is ubiquitous in most terrestrial and aquatic ecosystems. Recently MPs have been reported at high altitudes which indicates that air masses can transport and deposit MPs in the surface snow of high mountain ecosystems, however, whether MPs typification and abundance can be influenced by direction and origin of air masses still remains an open question. Here we present the first report of MPs above 5000 m a.s.l from surface snow of a glacier in the tropical Andes. We collected surface snow along an elevational gradient, from 5000 to 5400 m a.s.l., in the Antisana Glacier, in the northern Andes cordillera of Ecuador to analyze MPs abundance and polymeric identification with the Fourier Transform Infrared (FTIR) and also to hypothesized the possible MPs sources in this remote area by comparing the oxygen and hydrogen stable isotopic ratio composition of the snow samples and by analyzing the wind direction. We observed an average of 131 ± 24 MPs L-1 in our samples. Fibers corresponded to 70% of all MP shapes; FTIR results showed that MPs composition mainly included polyurethane, polyethylene, polyamide, polyester, and high-density polyethylene in surface snow. There were no statistically significant differences of MPs abundance among sampled elevations, and the isotopic ratio composition did not differ among locations. Our results suggest that MP that accumulated in the glacier may be transported from the east, across the Amazonia, by the prevalent eastward air flow. The absence of industrial cities at least 2000 km further east from Antisana, indicates that the remote Andean glaciers could constitute important depositional zones for long-distance transported contaminants.

Electrical resistivity methods to characterize the moisture content in Brazilian sanitary landfill.

The moisture content of the municipal solid waste (MSW) is a physical characteristic that plays a fundamental role in the stability and settlement of landfills. However, this physical index is difficult to monitor within the mass of landfilled MSW because it undergoes great variation due, mainly, to the heterogeneity and biodegradation of the waste. Brazilian MSW generally has a large amount of organic matter, that when biodegraded, generates a considerable volume of gases and fluids, aggravated by climatic conditions, such as high rainfall and temperatures. Hence, the importance of obtaining and evaluating the distribution of moisture content in the MSW mass over time. Currently, the electrical resistivity properties have been presented as an interesting approach to obtain the moisture content in landfills indirectly. This study aimed to apply geoelectrical methods as a tool to obtain and evaluate the moisture content distribution in an experimental cell of a sanitary landfill using Archie's law, which correlates the volumetric moisture content and electrical resistivity. Moisture content values were obtained in laboratory tests with MSW samples collected in two vertical holes and electrical resistivity measurements by means of vertical electrical sounding. The moisture content and the resistivity values of the samples were used to calculate the parameters a and m of Archie's law. This allowed to convert the resistivity tomography to moisture content tomography. The good correlation achieved between the moisture content calculated by Archie's law and that obtained from samples indicates that the use of electrical resistivity methods is useful to assess and monitor quantitatively the moisture content in landfills using Archie's law.

Groundwater governance: The illegality of exploitation and ways to minimize the problem.

In Brazil, there are about 2.5 million tubular wells in which 88% of them are illegal, extracting more than 17,580 Mm3/yr. This irregular use may cause sustainability issues that may be economic, social, or environmental (overexploitation, well losses and associated increases of water conflicts; aquifer contamination; and land subsidence). This paper aims to address the illegal wells in Brazil and discuss measures to minimize it. Conclusions indicate that users do not understand the aquifer dynamic and, therefore, do not have a proper understanding of problems such as loss of water quality and quantity caused by the excess of groundwater exploitation. This creates a false idea that there are no water conflicts among users, which causes a lack of engagement by society. Without groundwater users and stakeholder pressure, the government does not aim to control or close illegal wells, and the "vicious cycle" persists. The one way to break this "vicious cycle" would be programs of social communication and users' participation, coupled with improvements to the control apparatus and inspection from State institutions, making sure that there is correct management and not only legislations that are not applied.

Groundwater resources in Brazil: a review of possible impacts caused by climate change.

Groundwater has a strategic role in times of climate change mainly because aquifers can provide water for long periods, even during very long and severe drought. The reduction and/or changes on the precipitation pattern can diminish the recharge mainly in unconfined aquifer, causing available groundwater restriction. The expected impact of long-term climate changes on the Brazilian aquifers for 2050 will lead to a severe reduction in 70% of recharge in the Northeast region aquifers (comparing to 2010 values), varying from 30% to 70% in the North region. Data referring to the South and Southeast regions are more favorable, with an increase in the relative recharge values from 30% to 100%. Another expected impact is the increase in demand and the decrease in the surface water availability that will make the population turn to aquifers as its main source of water for public or private uses in many regions of the country. Thus, an integrated use of surface and groundwater must therefore be considered in the water use planning. The solution of water scarcity is based on three factors: society growth awareness, better knowledge on the characteristics of hydraulic and chemical aquifers and effective management actions.