Microplastics (MPs), small plastic particles resulting from the degradation of larger plastic items and from primary sources such as textiles, engineered plastic pellets, etc., have become a ubiquitous environmental pollutant. As their prevalence in the natural environment grows, concerns about their potential impacts on human health have escalated. This review discusses current research findings on the presence of MPs in organs such as the liver, blood, heart, placenta, breast milk, sputum, semen, testis, and urine, while also exploring plausible mechanisms of translocation. Furthermore, the review emphasizes the importance of understanding the potential toxicological effects of MPs on various physiological processes within these organs and their broader implications for human health. This review also examines the pathways through which MPs can enter and accumulate in human organs and bodily fluids, shedding light on the intricate routes of exposure and potential health implications. It is worth noting that the invasive medical procedures may permit direct access of MPs to the bloodstream and tissues, serving as a potential contamination source. However, it is evident that a comprehensive understanding of MPs’ invasion into human organs is vital for effective mitigation strategies and the preservation of both human health and the environment.

Widespread use of plastics and mishandling has resulted in severe environmental issues affecting seed germination and seedling growth. This study investigates the effect of polyethylene microplastics (740-4990 nm PEMPs) on lentil (Lens culinaris) seed germination and seedling growth using Biospeckle Optical Coherence Tomography (bOCT), a technique that we successfully demonstrated earlier in visualizing the internal activity of plants. Lentil seeds were exposed to PEMPs bioassay for seven days with 10, 50, and 100 mg L^-1 concentrations. The average speckle contrast was calculated after 0 h, 6 h, 12 h, and 24 h of exposure, and statistically significant differences were observed just after 6 h of exposure under all the treatments. However, with conventional parameters, germination viability, germination rate, root and shoot lengths, fresh and dry seedling weights, and antioxidative enzymes, no significant effect was observed until 2 d of exposure. The results revealed that the presence of PEMPs significantly reduced the internal activity at the initial stages that could be visualized only by the use of bOCT, which has never been observed till now. Our results demonstrated for the first time the effect that microplastics indeed could hinder the internal activity during germination of the seeds, possibly resulting from the physical blockage of pores leading to stunted growth at later stages.

The extraction of mineral resources from mines plays a vital role in global socio-economic development. However, acid mine drainage (AMD) has been one of the major pollutants, and a vast area of the agricultural fields has been polluted. Therefore, techniques for monitoring the response of plants to AMD that arise during mineral extraction are necessary. In addition, such a technique becomes especially valuable to understand how the plants could play a role in the phytoremediation of AMD. We propose the use of biospeckle Optical Coherence Tomography (bOCT) to investigate the response of Kaiware daikon seeds under the exposure to simulated AMD at two different concentrations of 40 mL/L and 80 mL/L. OCT images of the Kaiware daikon seed were obtained at a speed of 10 frames per second (1 frame: 512 × 2048 pixels) for a few tens of seconds. For each pixel of the OCT structural images, the contrast across the temporal axis was calculated to give biospeckle contrast OCT images (bOCT images). It was found that bOCT images clearly distinguished the changes due to 40 mL/L and 80 mL/L of AMD treatments from the control within a short time of around an hour, compared to the conventional OCT images that failed to show any changes. This variation was found to be statistically significant and could reflect the internal activity of the seeds. The proposed bOCT method could be a rapid, non-invasive technique for screening suitable plants in AMD phytoremediation applications.

There is growing recognition of the impact of the rising presence of microplastics (MPs) on terrestrial plant growth and, in general, the terrestrial ecosystem. Simultaneously, there is growing heavy metal accumulation in agricultural lands at an astonishing rate owing to the overwhelming use of chemical fertilizers, herbicides, and weedicides. Thus, there is a need to investigate the synergetic effect of MPs along with heavy metals on the inducing combined toxicity. This study investigates effects at smaller exposure periods of a few hours using a novel optical imaging technique, Biospeckle Coherence Tomography. Biospeckle Optical Coherence Tomography (bOCT) is a novel optical imaging technique that we successfully demonstrated earlier in visualizing the internal activity of plants. Previous studies of authors using the bOCT technique have demonstrated its potential in the independent application of polyethylene microplastic (PEMPs) as well as zinc within 6 h after their treatments. The strong inhibitory effect of 100 mg L^-1, Zn, and PEMPs alone on the germination of Lens culinaris could be visualized with bOCT. The current study demonstrated that against expectation, combined effects of Zn toxicity were reduced when combined with MPs. This is suggested due to the significant reduction of Zn uptake by the seedlings through the interaction of Zn and MPs in an aqueous solution. Mass-spectrometry results also indicate a reduced intake of Zn. Our findings suggest that PEMPs could be able to reduce the over-availability of Zn, thus mitigating the Zn toxicity on lentils.

Growth of plants, apart from being complex and highly dynamic, is directly dependent on the environmental conditions, particularly the quality of soil for terrestrial plants and the water quality for aquatic plants. Presence of microplastics in the environment may affect the plant growth in numerous ways depending on the contents of the growing medium. However, increasing presence of microplastics at an alarming rate due to its pervasive usage and mismanagement of plastics have led to significant environmental problems. Several research studies have been conducted as well as reviewed to investigate the toxic effects of microplastics on aquatic systems, but studies that investigate the toxic effect of microplastics on the terrestrial systems are limited. Hence, in this review the individual and the combined effects of microplastics on the growth of plants and seed germination in both aquatic and terrestrial ecosystems are concisely discussed. At the beginning accumulation of microplastics on aquatic and terrestrial ecosystem is discussed and the reasonable solutions are highlighted that can mitigate the effects from the widespread increase of the plastic debris. Thereafter, the individual and combined effect of microplastics on seed germination and plant growth is reviewed separately while summarizing the important aspects and future perspectives. This review will provide an insight into the existing gap in the current research works and thus could offer possible implications on the effect of microplastics on plant growth and seed germination in aquatic and terrestrial ecosystem. (C) 2021 GJESM. All rights reserved.

Objective: The aim of this study is to demonstrate the potential of applying the contrast of the speckles obtained as noise in optical coherence tomography (OCT) images to monitor short term activity changes during foliar application of phytohormones to a plant leaf. Plant growth hormone, gibberellic acid (GA₃) was sprayed onto the leaf of Chinese chives and after 60 min, OCT images (1 frame: 512 × 2048 pixels) were recorded at ten frames per second for a few tens of seconds. Results: Contrast across the temporal axis was calculated for each pixel of the structural images and biospeckle OCT contrast images were obtained under the conditions of before and after application of GA₃ for different concentrations 0, 40, and 100 μM. Application of 40 μM GA₃ failed to show any differences in the OCT structural images. However, bOCT contrast image was clearly different. Changes were found to be statistically significant. Although the mechanism for the contrast difference is not clear, it can be said there is a large change across the temporal scale with the application of GA₃. Demonstration of OCT utilizing the speckle contrast is believed to have the potential as a promising tool in plant physiology.