Enzyme Activities Transforming Sulphur in Brunic Arenosols in Forest Exposure to the Nitrogen Plants

This study has been conducted to assess the anthropogenic impact of the ANWIL S.A. nitrogen plants, one of the largest producers of nitrogen fertilizers in Poland, on the activity of arylsulphatase (AR), rhodanese (RDN) and catalase (CAT) related to sulphur transformation in forest soils. Samples of rusty brown soils were collected in the area adjacent to the ANWIL S.A. nitrogen plants in Włocławek. The profiles were located in the vicinity of the following production plants: No. W1—approximately 2.5 km away, No. W2—approximately 2 km away, and No. W3—approximately 0.8 km away. The control profile was established in the Tuchola Forest, which is part of the Biosphere Reserve. In order to recognize the impact caused by pollutants and the capacity of soil for re-generation, the resistance index (RS) and resilience index (RL) were determined. The highest RS value (0.964) was noted for rhodanese activity in layer Bv in W2, where the lowest RS for CAT (0.019) was observed. This study demonstrated the resilience of CAT activity in layer Bv in all the soil profiles adjacent to ANWIL. The highest resilience indicator was soil catalase activity. Enzymatic activity can be used to indicate the anthropogenic impact and the transformation of nutrients in forest soil.