The accident involving oil spill that occurred on the Brazilian coast in 2019 reached 2,880 km in extension, and more than 200 tons of oily material was removed from coastal environments in the northeast of the country in about five months. In the impact on beach environment there may still be non-visible residues and its by-products in subsurface, so that geophysical prospecting can be the suitable to evaluate the presence of remaining material. The evolution of environmental studies has required new research technologies. Geophysical methods have shown to be efficient in environmentalstudies, with the use of relatively new methods in Brazil that provide results with excellent coverage in the area and quickly. Among these methods stands out the Capacitive Resistivity Method. Environmental research work with this method has been reported with good results, but it is necessary to take into account the operational physical bases of the method so that the data is reliable. This work presents the results of tests carried out in a beach environment that was affected by oil. This environment is characterized by a medium of high conductivity, where data acquisition with equipment configured with smaller dipolar cables results in extremely noisy data. On the other hand, the configuration with larger dipolar cables allowed the transmission of higher electrical current to the ground resulting in the acquisition of good quality data.  The results showed that there are no more indications of oil residues on the beach studied.

The city of Urânia has been experiencing contamination problems in the Adamantina Aquifer since the 1970s, like many urban areas in São Paulo. It is extremely important to detect and monitor contaminated environments for prevention and repair, but one of the limitations is the limited access to the aquifer, especially establishing aquifer levels and the lithological characteristics of the unsaturated zone. This work identifies the aquifer recharge areas in Urânia most susceptible to anthropic degradation, by electroresistance contrasts. Vertical Electrical Surveys (VES) and Electrical Profiling provided a representative electrical dataset of the municipality. VESs and monitoring wells supported calculating the Dar Zarrouk Longitudinal Conductance Parameter and, further, the vulnerability index. The investigation also counted with other aquifer characteristics, such as its type, water level and lithology of the unsaturated zone. The resistivity profiles obtained by the Electric Walks showed values below 0.5 Ohm.m in the northeastern part of the city, close to the aquifer discharge region, where there is a concentration of organic contaminants. The vulnerability map indicated the southeast area as the most prone to contamination due to its permeable geological material and low thickness of its unsaturated zone. Low resistivity anomalies (<0.5 Ohm.m) were compared to previously published chemical analyzes, corroborating with their assessments, and showing the aquifer contaminated areas in and around the urban area of Urânia.

A cidade de Urânia enfrenta problemas de contaminação do Aquífero Adamantina desde a década de 1970, assim como muitas áreas urbanas paulistas. Uma das ferramentas fundamentais para o planejamento territorial é a cartografia da vulnerabilidade à contaminação de aquíferos. Uma das limitações de tal técnica é o difícil acesso ao aquífero, para o estabelecimento dos níveis aquíferos e das características litológicas da zona não saturada. Assim, este trabalho identificou as áreas de recarga do aquífero na região que são mais susceptíveis à degradação antrópica, a partir de uma técnica geofísica de sondagem elétrica vertical. Os resultados foram obtidos por meio das sondagens elétricas verticais e dos poços de monitoramento, e o índice de vulnerabilidade foi definido por meio do parâmetro de condutância longitudinal de Dar Zarrouk, aliado às características do aquífero, como o tipo de aquífero, o nível d’água e a litologia da zona não saturada. A partir do mapa de vulnerabilidade, foi possível indicar a área sudeste da região de estudo como a mais propensa à contaminação em razão do material geológico permeável e da pouca espessura da zona não saturada.