# Relationships between pesticides, polychlorinated biphenyls, blood parameters and oxidative stress of white stork Ciconia ciconia chicks in Poland

## TL;DR

This study examines how pesticides and PCBs in the blood of white stork chicks in Poland affect their blood parameters and oxidative stress.

## Contribution

The study reveals new evidence linking pesticide exposure to oxidative stress and blood parameters in white stork chicks.

## Key findings

- Higher beta-HCH levels correlate with lower oxidative stress enzyme activity and leukocyte concentration.
- 4.4′-DDE levels are negatively associated with catalase activity.
- Male stork chicks have higher PCB concentrations than females.

## Abstract

The white stork Ciconia ciconia is a bird species located at the top of the trophic pyramid in grassland and wetland ecosystems. This charismatic species is susceptible to pesticides and their environmental residues. In 2016, we collected blood samples from 114 white stork chicks across Western and Southern Poland. Chicks were sexed by molecular analysis and aged by development pattern. We studied the relationship between the concentration of pesticides (beta-HCH, heptachlor, aldrin, endrin, 4.4′-DDD, 4.4′-DDE and 4.4′-DDT) and of PCB in the chicks’ blood with blood morphology and biochemistry parameters in the blood. The mean (± SD) values of concentrations of above detection level pesticides were: for (1) beta-HCH 4.139 ± 19.205; (2) 4.4′-DDE 9.254 ± 91.491 and additionally (3) PCB 16.135 ± 44.777 ppb. We found negative relationships between beta-HCH and oxidative stress enzyme activity in the blood, between beta-HCH and leukocyte concentration and between 4.4′-DDE and catalase activity. We also found a positive relationship between the concentration of pesticides in blood and the age of chicks. Interestingly, we found a higher concentration of PCB in the blood of male stork chicks than in female stork chicks. We provide more evidence that the presence of pesticides in the environment can be a strong stress factor, shaping the health status of birds.

The online version contains supplementary material available at 10.1007/s11356-024-34072-5.