Bryomonitoring of atmospheric elements in Sphagnum sp. rarely growing bryophyte in the Indian Himalayan region of Uttarakhand

For a range of metals originating from both natural and anthropogenic sources, bryophytes are helpful biological markers of environmental contamination. This research focuses on recent changes in air quality and uses a passive biomonitoring technique to estimate atmospheric metal deposition and its seasonal trend in Sphagnum sp., as well as its substrate, from Nainital, Bhimtal, and Mangoli of Uttarakhand, India. Bryophyte samples from the summer, winter and monsoon seasons were collected from equally spaced locations. Due to the large volume of travel, a high metal concentration was discovered in Nainital. The metal deposition loads were reported in the following order: Zn > Cu > Pb > Cd. Quantitative analysis of these elements in vegetative/plants and substrate/soil showed an increase in metallic content during summer. The results indicate this moss may serve as an important tool in estimation of both aerial pollution and mineral enrichment in soil. Such research is vital since development is frequently accompanied by unfavourable changes in air quality and negative impacts of air pollution on human health, agricultural production, and natural ecosystems that need to be monitored and mitigated.


Introduction Introduction Introduction Introduction
Both active and passive bioindicators are employed with bryophytes. Numerous earlier researches illustrate the links between a community of bryophytes and the factors that affect their ecology (Muotka and Virtanen, 1995;Virtanen et al., 2001;Heino and Virtanen, 2006;Scarlett and O'Hare, 2006;Rodriguez et al., 2014). In biomonitoring techniques, a wide range of bryophytes (mosses) are used, and they are one of the best tools for monitoring climate change (Gignac, 2001;Varela et al., 2010). They only acquire water from precipitation and atmospheric moisture, which makes them good air quality monitors. Because of their resistance to desiccation, they can continue photosynthesis under these circumstances and stay at the study site longer while being exposed to all potential toxins (Proctor and Tuba, 2002). In addition to these benefits, bryophytes are simple to work with because of their modest size and few specifications. Additionally, their cultivation, storage, and analysis do not cost much (Tingey, 1989). Due to their distinctive thallus composition, which consists of tissue sheets, bryophytes are particularly curious about how the environment affects them. Because they primarily receive their water, nutrients, and other essential ingredients from the atmosphere, they are thus in close proximity to their environment and react to environmental changes more quickly than vascular plants (Alam, 2013). Bryophytes also exhibit high levels of susceptibility and significant resistance to a variety of hazardous chemicals, heavy metals, and persistent organic pollutants. In several studies, they are recognised as excellent accumulation indicators because of their distinct uptake mechanisms (Zechmeister et al., 2003).
They are an extremely useful tool for biological monitoring, where the usage of organisms can provide details about the biosphere, such as the amount of metals in the air. As mosses can increase elements in exceptionally high concentration and make it simple to detect metals found in the environment, even at very low concentrations, bryomonitoring is a low-cost tool for measuring the potential emanation of metals (Alam, 2013;Di Palma et al., 2019).
The current study's main objective was to determine the extent of metal contamination in the Kumaon region of Uttarakhand by employing commonly occurring bryophyte as well as in substrate as a passive biomonitor, including sample collection, preparation, and processing.
The investigations of the current bryophyte research enable for the identification of high metal deposition locations as well as the examination of seasonal pattern in metal concentration. It is feasible to display even absolute amounts of the compounds present in selected bryophytes using spectroscopic investigations, which are utilized to detect the presence of heavy metal deposition in the air (Figueiraet al., 2002;Srivastava et al., 2014). The information gathered in this manner is appropriate for a long-term study of the heavy metal deposition at the investigational site (Grodziska and Szarek-Lukaszevska, 2001;Lucaciuet al., 2004;Chakrabortty and Paratakar, 2006).

Study area
The Kumaon and Garhwal hills make up the entire state of Uttarakhand. Due to its subtropical climate, Kumaon gets great weather all year round. The three fundamental seasons are summer, winter, and monsoon. The highest and minimum temperatures during the pleasant summers (March to June) range from 19 °C to 46 °C, respectively. A maximum temperature of about 25 °C and a lowest temperature of about 4 °C are typical throughout the winter months of November to February. From July to October, the monsoon receives a moderate amount of rain.

Sample design for mapping and identification
In accordance with the Indian weather conditions, Sphagnum sp. rarely occurring bryophyte sample was collected from three different Kumaon hill regions, Nainital (disturbed region), Bhimtal (buffer region), and Mangoli (undisturbed region) during three different seasons (summer, winter and monsoon). On the basis of morphological investigation, the specimen was correctly identified. Bryophyte sample was collected from each site after the exposure period of one season was through in order to conduct the metal analysis.

Sample treatment and chemical analysis
Samples of the harvested bryophyte were delivered to the lab in plastic bags. Unwashed samples were thoroughly removed of connected trash and dead matter. To get rid of dirt particles stuck in the bryophytes, a jet of air was used. Green bryophyte shoot apexes (1-2 cm) were dried in an air oven for 48 hours at 40 °C, and the samples were homogenised. HNO3 was used to degrade 0.5 g of homogenised bryophyte tissue at 120 °C for the analysis. When the liquid turned colourless, digestion was complete. The digested samples were filtered, and the clear solution was diluted to 50 mL with bi-distilled water before being examined by an atomic absorption spectrophotometer for Zn, Cu, Pb, and Cd. Plant metal concentrations are given as a percentage of their total dry weight. To check for potential contamination during extraction, a suitable blank (contain HNO3 and bi-distilled water) was utilized.

Allocation mapping
The map of sampling locations in the Kumaon region (Uttarakhand, India) is shown in Figure 1.

Statistical analysis
The whole data were statistically evaluated, and all analyses were conducted using triplicate transplants of bryophyte. To examine the impact of each treatment independently, data were expressed as mean ± standard error of the mean (SE), comparing variations in the metal concentration in different seasons.

Results Results Results
The results are summarized in the Tables 1-3 and Figures 2-4, each season's metal concentration results were expressed for plant in µg/g dry weight ± SE.  Table  Table Table  Table 2 2 2 2. . .
. Metal concentration (µg/g) ± SE in seasonally exposed ( Table  Table Table  Table 3 3 3 3. . . . Metal concentration (µg/g) ± SE in seasonally exposed (monsoon)  Zn, Cu, Pb, and Cd average values were higher than the baseline values (control site Mangoli). The sites in the undisturbed zone have been used as the control because, in comparison to the sites in the periphery zone, they have less people and less air pollution, which creates conditions that are almost ideal for the growth of bryophyte. Summer > winter > monsoon was the sequence of the seasons for metal accumulation (Zn, Cu, Pb, and Cd).        In all sites that were under construction in Uttarakhand's Kumaon region, the metal burden grew significantly. However, the peak gasoline consumption during the summer and then winter due to the multifold increase in tourist activities could be the cause of the highly significant seasonal tendency (Gerdol et al., 2000;Saxena et al., 2013;Srivastava et al., 2014).
The monsoon season sees a decline in tourism as well as pollution being washed away by rain. Furthermore, it is possible that the monsoon may cause growth (biomass) to expand more quickly than usual, which will lower the proportion of metal in the moss relative to biomass. Zn levels were high in bryophyte close to rural areas and close to roads along highways. Its cause can be attributed to the engine and vehicle wear and tear, with relatively little coming from exhaust emissions. In comparison to the baseline, the zinc concentration in bryophytes was considerably greater. In Nainital, Zn readings were higher during the course of year. It is possible that residents of these locations engage in agricultural activities and utilize Zn to encourage the growth of agricultural crops because these places were discovered to be affected by concentrations of Zn. As a result of its inclusion in pesticides and fungicides, the current conclusion is in agreement with that of Otvos et al. (2003).
These areas with high traffic densities were additionally enriched in zinc since asphalt pavement contains cobalt, nickel, and zinc (Sardans and Penuelas, 2005;Saxena et al., 2013). Diesel exhaust from small and large trucks used for transportation as well as the movement of these vehicles can be credited for the substantial zinc concentration detected in the bryophyte samples (Gerdol et al., 2000;Saxena et al., 2008Saxena et al., , 2010. The extreme Zn concentration at the Nainital site, had an impact on the results for Cu. Since these transplants were grown next to a road with heavy traffic, one of the possible sources of Cu contamination is motor-driven transport (Srivastava et al., 2014). According to Pearson et al. (2000) and Poikolainen et al. (2004), High engine wear and tear, household waste, laundry waste, and wasted kerosene oil in residential areas could all contribute to the high percentage of copper found alongside the road (Loppi and Bonini, 2000). It cannot be excluded out that copper has a high value in agricultural areas because it is a necessary component of fungicides, agricultural operations, and open burning of solid wastes (Gerdol et al., 2000;Otvos et al., 2003). Use of CuSO4 mixed kerosene, which is offered at a reduced price by the Indian government to citizens who fall below the poverty line, could possibly be another source of Cu in rural regions (BPL).
The current conclusion is consistent with that of Lopez et al. (1997), who also noted a rise in Cu level in populated areas. The current investigation has shown that the relationship between Pb content and distance from the road in a town's proximity is inverse. Sites with catchments exhibit a noticeably greater concentration than those observed at the baseline, with values peaking in Nainital. This shows that the reason there has been such a big rise in Pb levels is related to vehicle emissions. The results of the current study are consistent with those of Westerlund (2001), Adachi and Tainosho (2004), and Vidovic et al. (2005). This study demonstrates that despite the availability of lead-free gasoline, Pb is still widely distributed and its values remain high. The same may apply to the fact that Pb values were reduced per litre of gasoline, but that a 40-fold increase in traffic leads to a 40-fold rise in gasoline consumption, which increases the Pb value along the road. According to reports from other regions, vehicle traffic appears to be the main source of atmospheric Pb (Loppi and Bonini, 2000). Pb does not biodegrade and is still present in sediments, soils, and dust.
The highest levels of Cd were found in Nainital. The surface leaching rate of cadmium metal, which is low compared to other metals, is relatively high. The largest disparity between its distribution pattern and that of other metals suggests that they may have come from separate sources, as prior researchers have also suggested in their findings (Scharova and Suchara, 1998;Grodziska and Szarek-Lukaszevska, 2001). The use of coloured polythene bags, household garbage, abandoned plastic, and kitchenware could all be contributing factors to the Cd contamination throughout communities. Other sources of Cd in urban areas include the production of coloured plastic bags and paints and enamels that include cadmium compounds. Perhaps there are mining contaminants like Cd in the gasoline. The other contributing elements to this rise include service businesses that deal with metals (Alam, 2013). Nearly all elements showed excellent inter-elemental correlation. It suggests that the majority of the components under analysis come from similar origins or exhibit similar behaviour during long-range atmospheric transport over the course of the experiment. Because bryophytes can survive in a variety of harsh settings and are resistant to many compounds that are highly poisonous to other plant species, they provide excellent indicators for a wide range of contaminants. Aqueous liquids, gases, or particles that are environmental pollutants are deposited on the mosses. These sedentary species have a unique set of physiological adaptations that make them amenable to medium-and long-term environmental research (Teixeira et al., 2022).

Conclusions Conclusions Conclusions Conclusions
Overall, the findings point to automotive as a potential source of metals, which may have come about as a result of the high visitor activity during the summer and winter that is shown in every biomonitoring study, albeit this role is not yet evident. Additionally, municipal garbage, agricultural operations, opens burning of solid waste, and laundry are significant contributors of the rising metal burden. The current work promotes the use of specific bryophyte as biomonitors utilizing the biomapping approach, and it has been shown to be an excellent tool for determining the loads of metals in the atmosphere. Despite a decrease in the amount of lead in gasoline per litre, the number of automobiles has increased lead consumption, which has led to a rise in atmospheric lead concentration. Their simplicity, totipotency, and quick rate of reproduction making them the perfect organism for investigations connected to pollution. In addition, climate factors should also be taken into account as they may alter the effects of metals. The investigation brought to light the level of contamination in the study area as well as seasonal and annual metal pollution. Additionally, the study looked at the distribution of the selected metals and potential sources were discussed. The chemical analysis of the used bryophytes demonstrated that biomonitoring is a quick and reasonably priced approach for assessing the deposition of heavy metals in the surrounding ambient air and terrestrial ecosystem. Additionally, bryophytes are a supporting and useful monitoring tool, it could be helpful in biomonitoring studies involving similar metal pollution sources and to warn locals of possibly dangerous metal deposition growth.