Agronomic, phytotoxicity and phytopathological aspects of the effect of a paracetamol-containing drug, using winter wheat (Triticum aestivum) and garden cress (Lepidium sativum) as bioindicators, in the context of ecosafety

Abstract

The aim of the study was to investigate the impact of a paracetamol (PCM)- and additive-containing pharmaceutical (Infulgan) on growth characteristics of the seeds and seedlings of Triticum aestivum L. and Lepidium sativum L., phytotoxicity for L. sativum and on microbial contamination of seeds for T. aestivum. Methods. Winter soft wheat (T. aestivum) variety Bogdana and garden cress (L. sativum) variety Afrodita were used as test plants in laboratory conditions (Problematic Research Laboratory of “Ecological Biochemistry, Ichthyology and Biocorrosion” of T.H. Shevchenko National University “Chernihiv Colehium”). Aqueous solutions of Infulgan were used, which contained from 0.1×10–5 (10 mg/L) to 0.2% w/v (2,000 mg/L) PCM. In a growth test, the germination energy (%), germination (%) of T. aestivum and L. sativum seeds (3rd day), and some biometric and morphometric indices of seedlings were evaluated: T. aestivum: coleoptile length, number of roots on the 7th day; L. sativum — length of roots and shoot on the 5th day, simplified vitality index, relative root growth percentage. Phytotoxic indices were estimated for L. sativum only. The seed contamination incidence percentage (CIP) was also estimated. The results were analyzed using mathematical and statistical methods. Results. It was established that: 1) germination energy and seed germination rate did not change in all treatments with all concentrations of PCM investigated, when using the pharmaceutical Infulgan; 2) the growth indices of wheat and garden cress were statistically significantly impaired by a solution containing 0.05–0.2% PCM. Moreover, wheat seed was affected considerably by undetermined microbial contamination. A statistically significant decrease (1.2–2.5-fold) in the length of the wheat coleoptile compared to the control was recorded, along with an increase in the number of roots per seed (from 5.9±0.1 to 6.0±0.4 compared to 4.4±0.2 in the control). A significant increase in wheat root formation (5.2±0.2 roots per seed) was also recorded for PCM at 0.025%. PCM concentrations of 0.025%, 0.002%, 0.25×10–4 % and 0.1×10–5 % did not negatively impact plant growth indices. Conclusions. The germination energy and seed germination rate did not change under the influence of PCM as formulated in the pharmaceutical Infulgan at any concentration tested, however, the biometric indices of seedlings changed significantly. A substantial toxicity of Infulgan solutions was observed for L. sativum, at concentrations higher than 0.025%. Infulgan at a 0.05–0.2% PCM concentration enhanced root formation with 36%, where not only PCM, but also the excipients of the drug could have played a (so far unexplored) role. In wheat seed with higher PCM concentrations a substantial (so far undefined) microbial contamination of 77–100% was observed. Therefore, the ecotoxicity of PCM and its formulations should be assessed more comprehensively, taking PCM and its excipients (as formulation and as separate compounds) into account. At present known PCM concentrations characteristic of wastewater and environment appear not to pose a risk to the germination and growth of wheat and water cress.