The purpose of this paper is to determine the effect of heavy metals on the photosynthetic pigments of chlorophyll a, b and the carotenoids found in the cells of algae Chlorella vulgaris. In order to analyze the influence of heavy metals on Chlorella vulgaris algae, two heavy metals were chosen,...

One of the solutions implemented in order to improve the quality of soils exposed to pesticides is the application of sewage sludge, which is a by-product of wastewater treatment. As an organic substrate, it provides soil with important nutrients, such as nitrogen and phosphorus, and enriches it with organic matter, thanks to which it can be a valuable fertilizer. The aim of the presented research was to evaluate the influence of granulated sewage sludge (GSS) on the biological properties of soil treated with herbicides (MCPA and dicamba) and fungicides (thiophanate-methyl and azoxystrobin). The following aspects were investigated: the activity of selected soil enzymes, the genetic biodiversity of bacteria and fungi, and the abundance of the bacterial gene responsible for ammonia oxidation. A field experiment was conducted, in which granulated sewage sludge (GSS) was applied to soil at a single dose of 3 t/ha. Wheat (Triticum aestivum L.) was sown on the prepared plots. The herbicides (H) and fungicides (F) as well as their mixture (F + H) were applied to the plants in the appropriate growth phases in the doses recommended by the producer. The control was soil without sewage sludge (C). The samples taken were tested for: dehydrogenases, catalases and urease activities, genetic biodiversity structure of bacteria and fungi by TRFLP assay, and the abundance of the bacterial amoA gene by qPCR. On the basis of the obtained results, it was found that the application of pesticides to soil fertilized with sewage sludge influenced the enzymatic activity of soil, and their activity differed depending on the tested enzyme. The activity of URE and DHA on the plots with GSS was higher by approx. 20% and 30%, respectively, as compared to the plots without GSS application. Moreover, both the genetic biodiversity of microorganisms and the abundance of amoA gene differed depending on the variant of the experiment. The GSS treatment of soil significantly influenced the growth of the studied gene as compared to C, and its abundance was 9.15 log¹⁰ gene copies/g DW of soil. Due to the content of nutrients in sewage sludge, it can be a valuable fertilizer in agricultural crops treated with pesticides.

Mesotrione, as a widely used herbicide, is present in the environment in detectable amounts, causing serious damage. Here, we aimed to investigate the effect of mesotrione on Caco-2 cells and the possibility of its toxicity mitigation by cichoric acid. Therefore, we analyzed the cytotoxicity of both these compounds and the selected oxidative stress parameters, apoptosis and interaction of both the tested compounds with the cell membrane and their accumulation within the cells. In cytotoxicity studies, the stimulating activity of mesotrione was observed, and simultaneously, the inhibitory effect of cichoric acid was noticed. This effect was related to the results of oxidative stress analysis and apoptosis measurements. The activity level of key enzymes (glutathione peroxidase, catalase and superoxide dismutase) in Caco-2 cells exposed to cichoric acid was higher as compared to that of the control. The treatment with mesotrione did not induce apoptosis in the Caco-2 cells. The penetration of the studied compounds into the Caco-2 cells was measured by using an HPLC methodology, and the results indicate mesotrione’s high penetration capacity. The distribution of charge on the surface of the cell membranes changed under the influence of both compounds. Considering the mutual interactions of beneficial and potentially toxic food ingredients, it should be noted that, despite the observed favorable trend, cichoric acid is not able to overcome the toxic and cancer-stimulating effects of this pesticide.

In the present work, the conducted research concerned the determination of the toxicity and oxidative stress generation of the antidepressant fluoxetine (FLU), its metabolite nor-fluoxetine (Nor-FLU), the antibiotic nalidixic acid (NA), caffeic acid (CA) and their mixtures in three different environments: microbial medium (MM), raw wastewaters (RW) and treated wastewaters (TW). We evaluated the following parameters: E. coli cell viability, toxicity and protein damage, sodA promoter induction and ROS generation. It was found that FLU, Nor-FLU, NA, CA and their mixtures are toxic and they have the potency to generate oxidative stress in E. coli strains. We also detected that the wastewater, in comparison to the microbial medium, had an influence on the toxic activity and oxidative stress synthesis of the tested chemicals and their mixtures. Regardless of the environment under study, the strongest toxic activity and oxidative stress generation were detected after bacterial incubation with NA at a concentration of 1 mg/dm³ and the mixture of FLU (1 mg/dm³) with Nor-FLU (0.1 mg/dm³) and with NA (0.1 mg/dm³). The ROS synthesis and sodA promoter induction suggest that, in the case of the examined compounds and their mixtures, oxidative stress is the mechanism of toxicity. The analysis of the types of interactions among the substances constituting the mixtures in the wastewater revealed synergism, potentiation and antagonism.

Atrazine (ATR) is a widely used chlorinated herbicide from the s-triazine group. Due to the widespread use of ATR, it leaks into the environment and is detected in drinking water, exceeding the WHO-acceptable concentration of atrazine in drinking water, which is 2 μg/L. The aim of our study was to determine toxicity, protein degradation and genotoxicity of ATR at concentrations of 10; 1; 0.1; 0.01 mg/L on Chlorella vulgaris and with the application of E. coli bioluminescent biosensor strains. We measured the content of chlorophyll a, b, carotenoids in Chlorella vulgaris and the inhibition of this algae culture growth. E. coli RFM443 strains with gene constructs grpE:luxCDABE, lac:luxCDABE, recA:luxCDABE and E. coli strain MM294 trc:luxCDABE were used to determine toxicity, degradation of cellular proteins and genotoxicity. On the base of the obtained results, we concluded that ATR in the tested concentrations shows a toxic effect in relation to Chlorella vulgaris. ATR is toxic and genotoxic in E. coli RFM443 strains with grpE, lac, recA promoters and causes degradation of cellular proteins. Moreover, we have detected ATR toxicity toward the GFP protein in E. coli strain MM294-GFP. Taking into account the toxicity and genotoxicity of ATR documented in our research and in the experiments of other authors, we conclude that the presence of this herbicide in surface waters and drinking water is a serious threat to living organisms.

The purpose of this paper is to determine the influence of color temperature of Light Emitting Diode (LED) diodes and illumination intensity on the content of photosynthetic pigments of chlorophyll a, chlorophyll b and carotenoids in Chlorella vulgaris algae cells. Choosing the right color temperature and intensity of illumination can favorably affect the growth of algae. In particular, it can contribute to the efficiency of the photosynthesis process and the amount of produced biomass from Chlorella vulgaris algae. In the spectrophotometric studies, the highest content of chlorophyll a, chlorophyll b and carotenoids was found in cultures illuminated with very cold white light (8500 K) with an intensity of 500 μmol/m²s. The highest measured content of chlorophyll a (Chl a) pigments was 48.29 mg/L, Chl b pigment was 23.25 mg/L and carotenoids pigment was 12.65 mg/L; the smallest content of pigments for Chl a (11.48 mg/L), Chl b (4.69 mg/L) and carotenoids (3.03 mg/L) was found in the sample illuminated with warm white light (3200 K) with an intensity of 50 μmol/m²s. The highest amount of dry organic matter amounting to 2.0 g/L was found in a sample illuminated with warm white light (3200 K) with an intensity of 250 μmol/m²s, then 1.91 g dry organic mass (DOM)/L for very cold white light with an intensity of 250 μmol/m²s, and 1.48 g DOM/L for very cold white light with an intensity of 50 μmol/m²s. The obtained results show that a higher content of photosynthetic pigments does not directly affect the increase of the amount of dry organic matter.