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Water and soil were considered for a long time to be renewable resources, but currently, the opposite is demonstrated and water and soil pollution represent an important factor in causing ecological imbalances that can have serious consequences for the biosphere. The main pollution generating process has become industrialization and technologicalization. The objective of this study was to investigate through a field study the physico-chemical parameters of the Jiu river from 15 specific locations, determining the values of pH, hardness, and dissolved oxygen, for two years (2016/2017). The water samples were collected in special containers and stored in the refrigerator at 4 °C until the determinations were made. To determine the physico-chemical parameters, the portable spectrophotometer model DR 1900 (Hach, Romania) was used and the following physico-chemical determinations were performed: pH; hardness; conductivity; dissolved oxygen. For the water samples collected from the Jiu river on the territory of Gorj county, pH values were obtained between 7.0 - 9.2 in 2016 and between 7.4-8.5 in 2017. The water samples collected from the territory of Dolj county were obtained pH values between 6.0 - 9.2 / 2016 and between 7.0 - 9.0 / 2017. The pH value was higher in January and July in 2016 compared to the values obtained in the same months of 2017. The oxygen concentration in the water samples taken from the Jiu river, both in Gorj and Dolj county was increased in both 2016 and 2017, classifying the Jiu River in ecological class 1 (very good), according to Order 161/2006. The values of the amount of O2 (mg / L) were higher in 2016, both in January and July, compared to the same period of 2017. The value of O2 concentration was lower in the samples taken downstream compared to the samples taken upstream.

The qualitative trials were conducted by exposing earthworms to diverse contaminants sources using standard earthworms’ avoidance tests (considered useful ab initio indicators). For two years, we observed the Jiu River pollution points. We observed soil traits in 15 sampling points from two neighboring Romanian counties where Jiu River flows, by evaluating the risk of pollution on Eisenia fetida earthworms. The ISO: 11268-2:2015 acute static test was used, following the ethological and bodily features of E. fetida earthworms for 14 days, and then the results obtained for clean soils vs. those presumed polluted were statistically analyzed. Results disclosed statistically significant values (p < 0.05) for the two-way ANOVA and Tukey multiple comparisons tests used for the soil samples thought to be polluted. The mortality percentages by location/replica/year/county find out a high statistical correlation documenting observations related to soil samples gathered from 10 m (p < 0.01) and 30 m (p < 0.001). Compared with the control, the statistical analysis of Relative Growth Rate (RGR) (p < 0.05) and Specific Growth Rate (SGR) (p < 0.01) confirmed that, in the case of soil samples collected from 10 and 30 m from the Jiu River’s axis, the earthworms did not gain weight, qualitatively attesting the pollution suspicion/presence of chemical factors potentially pernicious for earthworms.