Typha latifolia (broadleaf cattail) as bioindicator of different types of pollution in aquatic ecosystems-application of self-organizing feature map (neural network)

Emergent (branched bur-reed-Sparganium erectum L.) and submergent (river water-crowfoot-Ranunculus fluitans Wimm., 1841) aquatic plants as metal biosorbents under varying water pH conditions in laboratory conditions

A laboratory experiment was performed to find out the potential bioaccumulation of metals (Al, Cu, Cd, Ni, Pb, Fe, Mn) in aquatic plants acting as natural biosorbents in the environment depending on the variation of water pH. Two plants were selected for the study: branched bur-reed-Sparganium erectum L., as a representative of emergent plants; and river water-crowfoot-Ranunculus fluitans Wimm., 1841, as a representative of submergent plants. The bioaccumulation of metals in plants relative to water (BCFW) was determined, and the metal pollution index (MPI) was calculated. The metal content in water and plants before the experiment was arranged in the following series of increasing values: Cd = Ni < Cu < Pb < Mn < Al < Fe (water) and Cd < Cu < Ni < Pb < Al < Fe < Mn (in both plants). The lowest concentration of cadmium was found in water both at the end and beginning of the experiment. In turn, aluminum level increased, and its concentration was the highest in both acidic and alkaline water. This suggests that aluminum is definitely more available to the organisms living in it under such conditions, and in higher concentrations may be a limiting factor for them. Bioaccumulation of metals (BCFW) in neutral and alkaline environments was higher in branched bur-reed, and in acidic conditions in river water-crowfoot. This may provide a basis for using specific plant species to selectively accumulate metals depending on the range of water pH. This is also supported by the MPI values, which indicate that they have a very high and often the highest impact on metal pollution levels. The observed variability of metals bioaccumulation against the condition of hydromacrophytes makes it possible to consider these plants as biosorbents used in constructed biological treatment plants, which, depending on the species placed there, can selectively absorb particular trace elements. The plants used in the experiment are common hydromacrophytes of Europe, so they can be used in the construction of artificial wetlands across the continent. The apparent diversity of metal accumulation in relation to hydromacrophytes indicates that this type of site can be inhabited by specific species, which can significantly improve the purification of natural or anthropogenic water reservoirs, i.e., those that are intended to perform a filtering function.

Improving the Accuracy of a Biohybrid for Environmental Monitoring

Environmental monitoring should be minimally disruptive to the ecosystems that it is embedded in. Therefore, the project Robocoenosis suggests using biohybrids that blend into ecosystems and use life forms as sensors. However, such a biohybrid has limitations regarding memory-as well as power-capacities, and can only sample a limited number of organisms. We model the biohybrid and study the degree of accuracy that can be achieved by using a limited sample. Importantly, we consider potential misclassification errors (false positives and false negatives) that lower accuracy. We suggest the method of using two algorithms and pooling their estimations as a possible way of increasing the accuracy of the biohybrid. We show in simulation that a biohybrid could improve the accuracy of its diagnosis by doing so. The model suggests that for the estimation of the population rate of spinning Daphnia, two suboptimal algorithms for spinning detection outperform one qualitatively better algorithm. Further, the method of combining two estimations reduces the number of false negatives reported by the biohybrid, which we consider important in the context of detecting environmental catastrophes. Our method could improve environmental modeling in and outside of projects such as Robocoenosis and may find use in other fields.

Possibility of Metal Accumulation in Reed Canary Grass (Phalaris arundinacea L.) in the Aquatic Environment of South-Western Polish Rivers

A four-year research study was conducted on aquatic plants (reed canary grass) growing in the beds of three rivers and their tributaries in Lower Silesia, Poland. Metal contents (Cu, Cd, Ni, Pb, Zn, Fe, Mn) were determined in plant samples, metal accumulation in water (BCFw) and sediment (BCFB), Metal Pollution Index (MPI) and Enrichment Factor (EF) were calculated. The highest contents of copper, lead, nickel and cadmium were found in reed canary grass sampled from the Nysa Szalona River. The highest values were recorded for zinc in the Bystrzyca River, and for iron and manganese in the Strzegomka River. The series of metals were as follows: Nysa Szalona and Strzegomka: Cd < Ni < Pb < Cu < Zn < Mn < Fe, Bystrzyca: Cd < Ni < Cu < Pb < Zn < Mn < Fe. Throughout the study period, the lowest values of metals in plants were recorded in 2015 and 2018, and the highest in 2017. The general picture of MPI in aquatic plants is arranged in the series Bystrzyca < Strzegomka < Nysa Szalona. These values classify the studied material at a high level of pollution in all rivers. In the comparison of the two extreme sites, i.e., source−mouth, higher values were found at the mouth of the reservoir, which suggests that metals move with the water current and accumulate more with the direction of the river flow, which is most likely a consequence of the influence of the catchment area as the source of metals. The series of EF enrichment factor values were as follows: Bystrzyca—Ni < Cd < Fe < Cu < Zn < Mn < Pb, Nysa Szalona—Ni < Fe < Zn < Cd < Mn < Cu < Pb, Strzegomka—Ni < Cd < Fe < Zn < Cu < Pb < Mn. For all the samples studied, the values found in spring were much higher than in autumn, which indicates the great importance for research in that area. The levels of copper and iron were within the range of moderate values, lead and manganese reached very high and exceptionally high values, and the remaining metals were within the values described as significant. Bioaccumulation of metals determined relative to bottom sediments was highest in 2017 and lowest in 2018, while bioaccumulation relative to water was highest in 2018 and lowest in 2016. The four-year study found that the metal content in reed canary grass was mostly within the range of mean values presented in the literature from moderately polluted areas. Also, no significant deviation was found from levels that have been recorded for the same rivers for more than two decades.

Mitigation of Deicing Salt Loading to Water Resources by Transpiration from Green Infrastructure Vegetation

Green infrastructure (GI) protects aquatic ecosystems from stormwater runoff caused by urban development. Bioretention (BR) is a typical GI system wherein stormwater runoff is routed to a soil basin planted with vegetation and has been shown to reduce deicing salt loads in surface runoff, but the removal mechanism of salt is poorly understood. This study explores the potential of different vegetation types to reduce deicing salt released from a BR by transpiration. Six engineered soil media columns were built in a laboratory greenhouse to simulate a 1012 m2 BR basin along Lorton Road, Fairfax County, VA, USA. The effect of vegetation type (Blue Wild Indigo and Broadleaf Cattail) and influent salt concentration on flow volume and salt mass reduction were quantified for multiple storm events. For all storm events, chloride inflow concentrations, and vegetation types, Cl− load reduction ranged from 26.1% to 33.5%, Na+ load reduction ranged from 38.2% to 47.4%, and volume reductions ranged from 11.4% to 41.9%. Different inflow salt concentrations yielded different removal rates of deicing salt, and for a given column, salt removal decreased over sequential storm events. For each influent salt concentration, columns planted with Broadleaf Cattail (BC) performed better for volume and salt mass reductions than columns planted with Blue Wild Indigo (BWI), which in turn performed better than the controls.

The Morphological and Functional Organization of Cattails Typha laxmannii Lepech. and Typha australis Schum. and Thonn. under Soil Pollution by Potentially Toxic Elements

The aim of this study is to investigate the adaptation of two species of cattail Typha australis Schum. and Thonn. and Typha laxmannii Lepech. based on analysis of the morphological and anatomical features of their vegetative and generative organs to soil pollution with potentially toxic elements (PTE) in the riparian zones of the sea edge of the Don River delta (Southern Russia). Both species of the cattail are able to accumulate high concentrations of Ni, Zn, Cd, Pb and can be used for phytoremediation of polluted territories. The pattern of PTE accumulation in hydrophytes has changed on polluted soils of coastal areas from roots/rhizomes > inflorescences > stems to roots/rhizomes > stems ≥ inflorescences. The comparative morphological and anatomical analysis showed a statistically significant effect of the environmental stress factor by the type of proliferation in T. australis, and species T. laxmannii was visually in a depressed, deformed state with mass manifestations of hypogenesis. These deformations should be considered, on one hand, as adaptive, but on the other, as pathological changes in the structure of the spikes of the cattails. Light-optical and electron microscopic studies have shown that the degree and nature of ultrastructural changes in cattails at the same level of soil pollution are different and most expressed in the assimilation tissue of leaves. However, these changes were destructive for T. australis, but for T. laxmannii, these indicated a high level of adaptation to the prolonged technogenic impact of PTE.

A Review of Current and Emerging Approaches for Water Pollution Monitoring

The aquatic ecosystem is continuously threatened by the infiltration and discharge of anthropogenic wastewaters. This issue requires the unending improvement of monitoring systems to become more comprehensive and specific to targeted pollutants. This review intended to elucidate the overall aspects explored by researchers in developing better water pollution monitoring tools in recent years. The discussion is encircled around three main elements that have been extensively used as the basis for the development of monitoring methods, namely the dissolved compounds, bacterial indicator, and nucleic acids. The latest technologies applied in wastewater and surface water mapped from these key players were reviewed and categorized into physicochemical and compound characterizations, biomonitoring, and molecular approaches in taxonomical and functional analyses. Overall, researchers are continuously rallying to enhance the detection of causal source for water pollution through either conventional or mostly advanced approaches focusing on spectrometry, high-throughput sequencing, and flow cytometry technology among others. From this review’s perspective, each pollution evaluation technology has its own advantages and it would be beneficial for several aspects of pollutants assessments to be combined and established as a complementary package for better aquatic environmental management in the long run.

Ecological types and bioindicator macrophyte species of pollution of riparian vegetation of Oued Lârbaa in Taza City of Morocco

The object of our study is devoted to the Spermatophyta of the wetlands of Oued Lârbaa, the main river of the city of Taza, Morocco, and which is under strong anthropic pressure. Our work involved a floristic inventory, to define ecological types and groups of dominant plants in relation to seasonal factors and types of pollution, explaining the meaning of their presence. For this purpose, floristic sampling was carried out along the Oued during the dry periods (2017 and 2018) and the wet period (2018). A total of 66 plant species belonging to 54 genera and 30 families were identified, including 44 species during the wet period (2018) and 27 species during the dry periods (2017 and 2018). This difference is due to the favorable conditions for vegetation development during the period of precipitation and to the increase in pollution rates during the dry season. The inventoried flora shows the dominance of 10 ecological types characterized by the following plants: Cynodon dactylon, Arundo donax, Olea europaea, and Tamarix gallica (common between the two periods); Dittrichia viscosa, Visnaga daucoides, Typha angustifolia, and Ricinus communis (during the dry periods of 2017 and 2018); and Juncus maritimus and Populus nigra (during the wet period of 2018). The ecological types identified in this work decrease from the dry season to the rainy season, while specific richness increases. These dominant plants are all considered as bioindicators of the presence of heavy metals.

Accumulation of heavy metals in a macrophyte Phragmites australis: implications to phytoremediation in the Arabian Peninsula wadis

Heavy metal-polluted wetlands could be remediated by harvesting metal accumulating plants, i.e., using phytoextraction. We studied a macrophyte Phragmites australis and assessed its potential to be utilized in the phytoremediation of heavy metal-polluted wetlands, specifically in wadis in the Arabian Peninsula. We sampled six polluted wadi sites and measured Mn, Fe, Ni, Cu, Zn, Cd, and Pb concentrations in the roots, rhizomes, stems, and leaves of P. australis, as well as in sediment and water. We analyzed the correlations between different plant organs, water, and sediment, and calculated the accumulation and translocation of the metals to the plant organs. We found indications for the accumulation of Cd, Zn, and Pb into P. australis and somewhat contradictory indications for the accumulation of Cu. We suggest that P. australis is a good candidate to be utilized in the phytoremediation of heavy metal-polluted wadis in the Arabian Peninsula where the few wadis offer many valuable ecosystem services for urban citizens.

Bioaccumulation of heavy metals from wastewater through a Typha latifolia and Thelypteris palustris phytoremediation system

Animal production is a source of heavy metals in livestock wastewater and also a key link in the food chain, with negative impacts on human and animal health. In intensive animal production systems, the most critical elements are zinc and copper. In order to development of innovative non-invasive strategies to reduce the environmental impact of livestock, this study assessed the ability of two plants, Typha latifolia and Thelypteris palustris, to bioaccumulate the heavy metals used in animal nutrition, from wastewater. Four mesocosms (width 2.0 m, length 2.0 m, 695 L of water, 210 kg of soil) were assembled outdoors at the Botanical Garden. Two of them were planted with T. latifolia (TL treated, n = 30; TL control, n = 30) and two with T. palustris (TP treated, n = 60; TP control, n = 60). In T0 a solution of a mineral additive premix (Zn 44.02 mg/L; Cu 8.63 mg/L) was dissolved in the treated mesocosms. At T0, d 15 (T1) and d 45 (T2) samples of roots, leaves, stems, soil and water were collected, dried, mineralized and analyzed using ICP-MS in order to obtain HMs content. We found that T. latifolia and T. palustris accumulate and translocate Zn, Cu from contaminated wastewater into plant tissues in a way that is directly related to the exposure time (T2 for Zn: 271.64 ± 17.70, 409.26 ± 17.70 for Cu: 47.54 ± 3.56, 105.58 ± 3.56 mg/kg of DM, respectively). No visual toxicity signs were observed during the experimental period. This phytoremediation approach could be used as an eco-sustainable approach to counteract the output of heavy metals.

Trace element accumulation in Salvinia natans from areas of various land use types

Salvinia natans meets many criteria for accumulative bioindicators and phytoremediation agents. However, the majority of studies on its bioaccumulation capacity were performed under controlled culture conditions. In the present study, Salvinia natans was investigated in a field study. Plant and water samples were collected from aquatic reservoirs located in areas with various dominant land uses (forested, agricultural, residential and industrial). Contents of 10 trace elements (As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn) and phytomass were measured to estimate the bioindication and phytoremediation potential of the species. Results showed that contents of trace elements in S. natans were high compared with other aquatic ferns (Azolla japonica, A. pinata) as well as free-floating vascular plants (e.g. Pistia stratiotes, Hydrocharis morsus-ranae, Lemna sp., Eichhornia crassipes). High bioaccumulation factors for Cu, Fe, Mn, Ni, Pb and Zn confirm accumulative abilities of the plant. Application of neural networks (SOFMs) confirmed that the species may be used in bioindication: the land use type determined the composition of substances carried into water reservoirs with runoff and trace elements accumulated in Salvinia tissues. Ferns in industrial areas had the highest content of Cd, Cu and Zn, while in residential areas plants showed the highest content of As, Co, Fe, Mn, Ni and Pb. Element contents in S. natans in forested areas were the lowest. High standing stocks of Cd, Mn and Ni indicated an important role of S. natans in the cycling of elements and potential use in their removal from aquatic ecosystems.

Detection of anomalous nitrogen dioxide (NO2) concentration in urban air of India using proximity and clustering methods

Owing to accurate future air quality estimates, need for detecting the anomalously high increase in concentration of pollutants cannot be adjourned. Plentiful approaches were proposed in the past to substantially determine the abnormal conditions, but most of the statistical approaches were computationally expensive and ignored the false alarm ratios. Thus, a hybrid of proximity- and clustering-based anomaly detection approaches to identify anomalies in the air quality data is suggested in this work. The Gaussian distribution property of the real-world data set is utilized further to segregate out anomalies. The results depicted twofold advantages of our approach, by efficient extraction of anomalies and with increased accuracy by reducing the number of false alarms. Specifically, the presence of NO₂ concentration in air is investigated in this work, considering its constant increase over decades as well as its inevitable health risks. Furthermore, spatiotemporal segments with anomalously high NO₂ concentrations for 14 residential, industrial, and commercial areas of five cities in India are extracted. To validate the results, a comparative analysis with existing approaches of anomaly detection and with two benchmark data sets is performed. Results showed that our method outperformed the existing methods of anomaly detection, when evaluated over metrics such as sensitivity, miss rate, and false alarms. Further, a detailed analysis of extracted anomalies and a detailed discussion about the factors responsible for such anomalies are presented in this work. This study is helpful in educating government and people about spatiotemporal, geographical, and economic conditions responsible for anomalously high NO₂ concentrations in air. Implications: Using our methodology, days with extremely high concentration of any pollutant in air, at any particular location, can be extracted. The reasons for such extremely high pollutant concentration on particular days of a year can be studied and preventive measures can be taken by the government. Thus, by identification of causes of anomalies, future similar events can be avoided. This would also help in people's decision making in case such events occur in the future.

Bioindication of human-induced soil degradation in enclosed karst depressions (dolines) using Ellenberg indicator values (Classical Karst, Slovenia)

One of the frequently used bioindication methods is Ellenberg indicator values (EIVs), which are commonly applied in Central Europe as bioindicators of ecological characteristics. However, very few studies have tested EIVs as a bioindication of human-induced soil degradation. We tested the ability of EIVs to distinguish between localities of degraded karst depressions (dolines) and localities of semi-natural (agricultural) soils in preserved dolines on the Kras Plateau (Classical Karst, SW Slovenia). We compared the results of bioindications of soil nutrient content (N), soil reaction (R) and soil moisture (M) with measured soil parameters. Low values of organic carbon, a slightly alkaline soil reaction and low organic sulphur content are chemical indicators of soil degradation in dolines, in comparison with preserved reference dolines (high organic carbon, slightly acid reaction, higher S). EIV reaction is the most reliable plant indicator value that can distinguish between degraded and non-degraded soil plots. According to a regression tree, sulphur (S) and C/N are the most important factors for division on the basis of EIV reaction. By applying the EIV reaction of diagnostic plant species, we significantly improved bioindication of soil degradation, although in the case of EIV nutrients, bioindication was not improved.

Long-term investigation of constructed wetland wastewater treatment and reuse: Selection of adapted plant species for metaremediation

A highly diverse plant community in a constructed wetland was used to investigate an ecological treatment system for human wastewater in an arid climate. The eight-year operation of the system has allowed the identification of a highly adapted and effective plant consortium that is convenient for plant-assisted metaremediation of wastewater. This constructed wetland pilot station demonstrated effective performance over this extended period. Originally, there were twenty-five plant species. However, because of environmental constraints and pressure from interspecific competition, only seven species persisted. Interestingly, the molecular phylogenetic analyses and an investigation of the photosynthetic physiology showed that the naturally selected plants are predominately monocot species with C4 or C4-like photosynthetic pathways. Despite the loss of 72% of initially used species in the constructed wetland, the removal efficiencies of BOD, COD, TSS, total phosphorus, ammonia and nitrate were maintained at high levels, approximately 90%, 80%, 94%, 60% and 50%, respectively. Concomitantly, the microbiological water tests showed an extremely high reduction of total coliform bacteria and streptococci, about 99%, even without a specific disinfection step. Hence, the constructed wetland system produced water of high quality that can be used for agricultural purposes. In the present investigation, we provide a comprehensive set of plant species that might be used for long-term and large-scale wastewater treatment.