Tese
Análise do necropercolado em diferentes meios hidrogeológicos ocupados por cemitérios
Fecha
2022-10-26Autor
Fernandes, Gabriel D'Avila
Institución
Resumen
Even after death, human beings continue to generate contaminants in the form of necroleachate,
which may contain heavy metals and a series of other contaminants, altering the natural
characteristics of water and soil. The present work aims to identify the behavior of
necroleachate in cemeteries located in different hydrogeological environments and with
different forms of burial in the State of Rio Grande do Sul. In this way, this work proposes a
methodology for identifying the most appropriate areas for the installation of cemeteries,
aiming to mitigate the negative impacts caused to the environment and public health, raising
the hypothesis that takes into account that some natural characteristics are more determinant
than characteristics constructive actions regarding mitigation of environmental impacts. If the
natural characteristics are unfavorable, it is essential to adopt rigorous technical criteria that
guarantee environmental quality. The physical characteristics of the soil were determined with
granulometric analysis, the use of Guelph permeameter, and constant load in determining the
permeability coefficient and saturated hydraulic conductivity respectively. To determine the
water quality, Organic Matter, Dissolved Oxygen, Biochemical Oxygen Demand, Turbidity,
and Alkalinity were quantified. In the chemical characterization of the soil, samples were
collected using a Dutch manual auger at depths of 0, 0.5, and 1.5 m and determined by Atomic
Absorption Spectrometry. A geophysical survey was carried out in order to identify the
composition of the materials present in the subsoil, the depth of the water level, anomalies
found, and the dimensions of the possible contamination zone. The electroresistivity method
was used with the electric path technique, and the Dipole-Dipole arrangement, with intervals
of 5 meters between the electrodes, the Cemetery Quality Index was also proposed as an
instrument capable of identifying and characterizing the conditions in which the cemeteries
meet and possible future scenarios, based on the peculiar characteristics of each cemetery and
the local, natural characteristics of the environment. The case analysis was carried out in the
cemeteries of Catacumba in Caçapava do Sul-RS, in the Municipal Cemetery Jardim da
Saudade in Frederico Westphalen-RS, in the Cemetery Jardim da Saudade in Santa Maria-RS
and in the Municipal Cemetery São Francisco in Tramandaí-RS. In the water quality analysis,
for the turbidity parameter, the three municipalities where it was possible to collect samples
showed values higher than the Maximum Permissible Values, the same occurred for the
Biochemical Oxygen Demand. Using geophysics with the electroresistivity method and the
electric path technique, possible contaminated areas were identified in the cemeteries of
Caçapava do Sul-RS, Santa Maria-RS and Tramandaí-RS. After applying the Cemetery Quality
Index, the cemeteries of Caçapava do Sul-RS and Frederico Westphalen-RS presented an
Average condition, and Santa Maria-RS and Tramandaí-RS presented a very bad condition. It
was possible to identify that sandy soils have a greater capacity for necroleach percolation,
exposing groundwater to contaminants, justifying the construction of graves above ground level
to mitigate these impacts. With the application of direct analysis techniques allied to the
geophysical method, they proved to be an important tool for the sustainable management of
areas occupied by cemeteries.