The use of multivariate statistical methods for optimization of the surface water quality network monitoring in the Paraopeba river basin,Brazil

This study sought to evaluate and propose adjustments to the water quality monitoring network of surface freshwaters in the Paraopeba river basin (Minas Gerais, Brazil), using multivariate statistical methods. A total of 13,560 valid data were analyzed for 19 water quality parameters at 30 monitoring sites, over a period of 5 years (2008–2013). The cluster analysis grouped the monitoring sites in eight groups based on similarities of water quality characteristics. This analysis made it possible to detect the most relevant monitoring stations in the river basin. The principal components analysis associated with non-parametric tests and the analysis of violation of the standards prescribed by law, allowed for identifying the most relevant parameters which must be maintained in the network (thermotolerant coliforms, total manganese, and total phosphorus). The discharge of domestic sewage and industrial wastewater, that from mining activities and diffuse pollution from agriculture and pasture areas are the main sources of pollution responsible for the surface water quality deterioration in this basin. The BP073 monitoring site presents the most degraded water quality in the Paropeba river basin. The monitoring sites BP094 and BP092 are located geographically close and they measure similar water quality, so a possible assessment of the need to maintain only one of the two in the monitoring network is suggested. Therefore, multivariate analyses were efficient to assess the adequacy of the water quality monitoring network of the Paraopeba river basin, and it can be used in other watersheds.     

Using multivariate techniques as a strategy to guide optimization projects for the surface water quality network monitoring in the Velhas river basin,Brazil

Surface water quality monitoring networks are usually deployed and rarely re-evaluated with regard to their effectiveness. In this sense, this work sought to evaluate and to guide optimization projects for the water quality monitoring network of the Velhas river basin, using multivariate statistical methods. The cluster, principal components, and factorial analyses, associated with non-parametric tests and the analysis of violation to the standards set recommended by legislation, identified the most relevant water quality parameters and monitoring sites, and evaluated the sampling frequency. Thermotolerant coliforms, total arsenic, and total phosphorus were considered the most relevant parameters for characterization of water quality in the river basin. The monitoring sites BV156, BV141, BV142, BV150, BV137, and BV153 were considered priorities for maintenance of the network. The multivariate statistical analysis showed the importance of a monthly sampling frequency, specifically the parameters considered most important.     

Environmental monitoring model for a drainage basin obtained through spectral analysis of time series

The quality of results of an environmental monitoring plan is limited to the weakest component, which could be the analytical approach or sampling method. Considering both the possibilities and the fragility that sampling methods offer, this environmental monitoring study focused on the uncertainties caused by the time component. Four time series of nutrient concentration at two sampling points (PB1 and PB2) in the Ribeir?o Garcia basin in Blumenau, Brazil, which were significantly correlated to the spatial component, were considered with a 2-hour resolution to develop efficient sampling models. These models were based on the time at which there was the highest tendency toward adverse environmental effects. Fourier spectral analysis was used to evaluated the time series and resulted in two sampling models: (1) the SMCP (sampling model for critical period) that operated with 100% efficiency for registering the highest concentration of nutrients and was valid for 83% of the studied parameters; and (2) the SMGCP (sampling model for global critical period) that operated with 83 and 50% efficiency for PB1 and PB2, respectively.     

Degradation of 2,4,6-trichlorophenol in aqueous systems through the association of zero-valent-copper-mediated reduction and UVC/H2O2: effect of water matrix and toxicity assessment

Environmental Science and Pollution Research - The presence of toxic chlorinated compounds in drinking water, generated during the disinfection step in water treatment plants, is of great concern...     

Spatial Distribution of Soil Attributes in the Concórdia River Watershed in Southern Brazil

Using geographic information system, soil sampling, and statistical analysis to map anthropogenic effects on soil     

Recycling of gneiss rock waste in the manufacture of vitrified floor tiles

The present study focuses on the recycling of gneiss rock waste generated by the ornamental rock industry for manufacturing vitrified floor tile products. The gneiss rock waste came from a rock-cutting plant located in Santo Antônio de Pádua-RJ, Brazil. Initially the waste sample was characterized for chemical composition, X-ray diffraction, particle size, morphology, and pollution potential. Floor tiles containing up to 47.5 wt.% waste were prepared. The tiles were tested to determine their physical-mechanical properties (linear shrinkage, water absorption, apparent density, and flexural strength). Microstructural evolution was carried out by scanning electron microscopy. The results indicate that the gneiss rock waste could be used for vitrified floor tile production, resulting in a new possibility for recycling this waste and conserving natural resources.     

Mercury pollution in the Tapajos River basin, Amazon: mercury level of head hair and health effects.

There is increasing concern about the potential neurotoxic effects of exposure to methylmercury for the 6 million people living in the Amazon, even in regions situated far away from the gold mines (garimpos), considered to be the major source of mercury pollution. In November 1998, a spot investigation on mercury contamination was conducted in three fishing villages (Barreiras, Rainha, and Sao Luiz do Tapajos) on the Tapajos River, an effluent of the Amazon, situated several hundred kilometers downstream from the gold-mining areas. A total of 132 fishermen and their families volunteered for the current study. As was anticipated, the total mercury levels in the head hair collected from the fishing villages were relatively high (14.1-20.8 ppm on the average) and the number of subjects with a high total mercury level over 10 ppm (the least upper bound of a normal value) was 103 (78.0%) in total, along with various symptoms, thereby suggesting wide mercury contamination in the Tapajos River basin. Moreover, in view of the absence of other diseases (e.g., alcoholism or malaria), a high intake of fish containing a methylmercury level, and high hair mercury levels in addition to the various symptoms such as sensory disturbance (especially glove-and-stocking type, which is characteristic of Minamata disease), tremor, failure in two-point discrimination, and slight balancing failure, several subjects examined were diagnosed with mild Minamata disease. The findings obtained suggest, thus, that the mercury pollution in the Amazon should be crucially observed for head hair mercury level and health in a much broader region.     

Water environments: anthropogenic pressures and ecosystem changes in the Atlantic drainage basins of Brazil

Densely occupied drainage basins and coastal zones in developing countries that are facing economic growth are likely to suffer from moderate to severe environmental impacts regarding different issues. The catchment basins draining towards the Atlantic coast from northeastern to southern Brazil include a wide range of climatic zones and diverse ecosystems. Within its borders lies the Atlantic rain forest, significant extensions of semiarid thorn forests (caatinga), vast tree and scrub woodlands (cerrado) and most of the 6670 km of the Brazilian coast and its marine ecosystems. In recent decades, human activities have increasingly advanced over these natural resources. Littoralization has imposed a burden on coastal habitats and communities. Most of the native vegetation of the cerrado and caatinga was removed and only 7% of the original Atlantic rainforest still exists. Estuaries, bays and coastal lagoons have been irreversibly damaged. Land uses, damming and water diversion have become the major driving forces for habitat loss and aquatic ecosystem modification. Regardless of the contrast between the drought-affected northeastern Brazil and the much more prosperous and industrialized southeastern/southern Brazil, the impacts on habitat and communities were found equally severe in both cases. Attempts to halt environmental degradation have not been effective. Instead of focusing on natural resources separately, it is suggested that more integrated environmental policies that focus on aquatic ecosystems integrity are introduced.