Microplastics (MP) are now present in all ecosystems and undergo weathering processes, including physical or chemical degradation. Although most studies have been carried out on MP toxicity in the marine ecosystem, interest is growing for the terrestrial and entire aquatic compartments. However, the interface between both environments, also known as the soil/water continuum, is given little consideration in MP toxicity studies. Only a few studies considered the toxicity of artificially aged or soil field-collected MP on species living at this interface. The present study evaluates the impact of artificial and field aging polyethylene (PE) MP on the bivalve Scrobicularia plana, a key organism of the estuarine compartment, living at the soil/water interface. Clams were exposed for 21 days to environmental concentrations (0.008, 10 and 100 mu g L-1) of unaged as well as artificially and field aged PE MP. Toxicity was assessed from individual to molecular levels including condition index, clearance rate, burrowing behavior, energy reserves, enzyme activities and DNA damage. Results showed differential effects at all biological levels depending on the type and the concentration of the MP tested. Indeed, a decrease in burrowing behavior was observed in S. plana exposed to aged and field PE at low concentration (0.008 mu g L-1). In the gills of clams, exposures to aged PE (0.008 and 100 mu g L-1), virgin PE (10 mu g L-1) and field PE (all tested concentrations) decreased CAT activity while DNA damage increased after exposure to virgin PE (0.008 mu g L-1 and 10 mu g L-1) and field PE (0.008 mu g L-1). Our findings suggest that aging modifies the toxicity profile of PE polymer on S. plana and considering plastic from field at environmental concentrations is important when performing ecotoxicological studies.

Plastic has become indispensable in various industries, including agriculture, due to its affordability and versatility. Overutilizing plastic in agriculture produces microplastics, which pose significant environmental damage and cause several health implications. Hence, biodegradable mulch films were produced as an alternative to plastic by integrating atrazine (PXA) into the Poly (Vinyl Alcohol)/Xanthan gum polymer blend by solvent casting method. The PXA mulch films exhibited a compact structure and a slight reduction in crystallinity due to the crosslinking caused by the atrazine herbicide. The PXA mulch films excelled over the current biodegradable mulches, demonstrating a tensile strength of 42.73 +/- 0.51 MPa and an elongation at a break of 60.58 +/- 1.21 %. The addition of atrazine improved the ability of the PXA mulch films to block ultraviolet (UV) radiation, suppress the water vapour transmission rate (WVTR), and enhance the hydrophobic properties. The PXA mulch films, buried in soil for 15d, exhibited a degradation rate of 7.50 +/- 0.64 %, confirming their biodegradability. Herbicidal test was conducted with PXA mulch using Johnson grass as a weed. PXA mulch effectively retarded weed with enhancement of atrazine concentration. Kinetics investigations have verified that the release of the herbicide is governed by Fickian diffusion and exhibits a dependence on its concentration. For the impending harvest, soil fertility is also a crucial factor. PXA mulch films break down into organic matter to stimulate microbial development. Urease activity due to atrazine creates mulch soil rich in nitrogen content, and elevation in catalase activity ensures significant microbial development. These results of biodegradable PXA mulch films address the loss of soil fertility caused by applying PE mulching, which is the underlying cause of microplastic formation. These research findings suggest that PXA biodegradable mulch film could be an alternative to hazardous PE mulch in agriculture.

The aim of the study was to assess the impact of plant extracts from hemp inflorescences (H10-10% and H20-20%), as well as a mixture of extracts from hemp inflorescences, sage, and tansy leaves (M10-10% and M20-20%) on phytotoxicity and selected physiological and biometric parameters of wheat seedlings, as well as the biological activity of soil in a growth chamber experiment. In all experimental combinations, a low phytotoxicity of the extracts was observed in the form of leaf tip yellowing, classified as first-degree damage or its complete absence. The plant extracts and their mixtures, except for the H20 extract, had an inhibitory effect on the development of fungal pathogens, especially Fusarium spp. The H20 extract increased the fresh and dry weight of root seedlings. The tested extracts also had a positive effect on the chlorophyll content in seedlings. The highest chlorophyll concentrations were recorded for the seedlings sprayed with the M20 extract mixture. The applied plant extracts influenced the activity of soil enzymes. The highest activity of catalase and dehydrogenases was observed after spraying seedlings with M20, while the lowest was recorded after applying H10. Of all the tested groups of soil environment compounds included in the Biolog EcoPlates test, carbohydrates and carboxylic acids were most actively utilized. Conversely, amines and amides constituted the group of compounds utilized the least frequently. The present study demonstrated the high effectiveness of plant extracts on wheat seedlings due to their biocidal action against phytopathogenic fungi and increased biological activity of the soil. This research serves as an initial phase of work, which will aim to verify the results obtained under field conditions, as well as assess the biological stability of the extracts.