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The main objective of the research was to study the environmental "price" of the large-scale, milk production from a rarely known perspective, from the mapping of the estrogenic footprint (the amount of oestrus-inducer hormonal products, and the generated endoestrogens) in the resulting slurry in a dairy cow farm. These micropollutants are endocrine-disrupting chemicals (EDCs) and can be dangerous to the normal reproductive functions even at ng/kg concentration. One of them, 17ß-estradiol, has a 20,000 times stronger estrogenic effect than bisphenol-A, a widely known EDC of industrial origin. While most studies on EDCs are short-term and/or laboratory based, this study is longitudinal and field-based. We sampled the slurry pool on a quarterly basis between 2017 and 2020. Our purpose was testing the estrogenic effects using a dual approach. As an effect-based, holistic method, we developed and used the YES (yeast estrogen screen) test employing the genetically modified Saccharomyces cerevisiae BJ3505 strain which contains human estrogenic receptor. For testing exact molecules, UHPLC-FLD was used. Our study points out that slurry contains a growing amount of EDCs with the risk of penetrating into the soil, crops and the food chain. Considering the Green Chemistry concept, the most benign ways to prevent of the pollution of the slurry is choosing appropriate oestrus-inducing veterinary pharmaceuticals (OIVPs) and the separation of the solid and liquid parts with adequate treatment methods. To our knowledge, this is the first paper on the adaptation of the YES test for medicine and slurry samples, extending its applicability. The adapted YES test turned out to be a sensitive, robust and reliable method for testing samples with potential estrogenic effect. Our dual approach was successful in evaluating the estrogenic effect of the slurry samples.

The subject of our research is the comparative ecotoxicological examination of the bacterial slurry treatment system distributed by NCH Magyarorszag Kft. The experiment was carried out on a cattle calf rearing farm, in the 0-6 months age group section. The bacterial strains available in tablet form were multiplied in a container and added weekly to the slurry collected in the shaft. The purpose of bacteria treatment was to promote homogenization of the manure, reduce odors, and break down organic impurities. The ecotoxicological tests were carried out before, during and after the manure treatment at three sampling times. As a result of our research, it has been revealed that during the slurry treatment, the internal content values increased significantly, mostly the nitrogen forms, the biological oxygen demand and the dry matter content. The presence of the estrogenic effect remained considerable even at the end of the treatment. Based on the phytotoxicity test, the fertilizer treatment had a positive effect on the stem and root growth of each plant. The results of the soil toxicity test proved that untreated slurry loses its inhibitory effect on the vital activity of sensitive bacteria at higher dilutions. The common duckweed test revealed that above 150 dilution, the inhibitory effect of the slurry ceases in the samples at all three sampling times. In order to inhibit the growth of algae, the liquid fertilizer showed a stagnant-inhibiting tendency during the treatment. Based on our results, we came to the conclusion that the bacterial slurry treatment system was effective in terms of homogeneity, deodorization and decomposition of organic matter. However, it is recommended to apply it to the fields at a higher dilution rate or with a high soil water content. Further studies are needed regarding the removal of substances with hormonal effects, based on which recommendations can be developed for farmers.

A review of the international literature also found that the amount and the presence in slurry of oestrus inducer hormone preparations used in intensive dairy cattle production has not been investigated. In our study, we followed the path of 5 different sex-inducing drugs (alfaglandin, PGF, dinolytic, gonavet, ovarelin) including three active pharmaceutical ingredients (D-Phe6-Gonadorelin, Kloprostenol and Dinoprost-tromethamine) used in a cattle farm in Pest County from their use until their appearance in the slurry from 2017 to 2020. The study included a review of drug consumption and a seasonal analysis of the hormonal effects of slurry produced on the farm in quarterly cycles each year. We also tested separately the hormonal effects of the hormone preparations used on the farm. For the estrogenic effect tests, the yeast test with the human estrogenic receptor was used according to ISO 19040. Statistical evaluation of the results (Pearson correlation and Principal Component Analysis) was used to identify relationships between the use of sex inducers, the reproductive biology of the colony and the estrogenic effect of the slurry. We found that the estrogenic effects of slurry and sludge are strongly correlated. All three pharmaceuticals tested showed a strong correlation with the estrogenic effect of slurry/sludge. Our investigations confirm that slurry among other reasons due to its hormone and drug content shall be considered as a material that needs to be disposed of by new treatment methods before application to the field, because of its environmental and health risks.