APPLICATION OF THE BAYESIAN TRUST NETWORK AND MULTINOMIAL LOGISTIC REGRESSION TO PREDICT THE DEGREE OF CONTAMINATION OF AGRICULTURAL LAND

Исследованы возможности применения Байесовской сети доверия (БСД) и мультиномиальной логистической регрессии (МНЛР) для прогнозирования степени засоренности земель сельскохозяйственного назначения. Рассчитана вероятность превышения экономического порога вредоносности (ЭПВ) при участии обеих моделей. Выполнено моделирование влияния природных и антропогенных факторов с использованием БСД, а также осуществлен прогноз превышения ЭПВ по категориям с помощью МНЛР. Для обучения моделей использованы данные длительного многофакторного полевого опыта Кемеровского НИИСХ – филиала СФНЦА РАН. Учитывая особенности статистической выборки, определены основные предикторы моделей, влияющие на засоренность земель. Выбранными предикторами были агротехнические приемы (системы обработки почвы, предшественники) и агрометеорологические ресурсы (суммы активных температур воздуха, осадки). Объясненная часть дисперсии по мере Нэйджелкерка, составляет 80,9 %, что говорит о высоких прогностических возможностях применения МНЛР. Прогнозные результаты обеих моделей совпали в 79 % случаев, что указывает на достижение высоких показателей меры близости прогнозов по БСД и МНЛР. Обе модели показали достаточно высокую достоверность при верификации на эмпирических данных за прошлые годы и могут быть использованы в качестве инструмента для прогноза. Следующим этапом работы станет совместное использование БСД и МЛНР, которое может способствовать усилению достоинств обоих подходов и устранению недостатков отдельных из них. The possibilities of using the Bayesian Network of Trust (BSD) and multinomial logistic regression (MNLR) to predict the degree of contamination of agricultural land are investigated. The probability of exceeding the economic threshold of harmfulness (ETH) with the participation of both models is calculated. Modeling of the influence of natural and anthropogenic factors using BSD was carried out, and the forecast of the excess of ETH by category was carried out using MNLR. To train the models, data from a long–term multifactorial field experience of the Kemerovo Research Institute of Agricultural Sciences - branch of the SFSCA RAS were used. Taking into account the features of the statistical sample, the main predictors of the models affecting land contamination are determined. The selected predictors were agrotechnical techniques (tillage systems, precursors) and agrometeorological resources (sums of active air temperatures, precipitation). The explained part of the variance with the Nagelkerk measure is 80.9%, which indicates high prognostic possibilities of using MNLR. The forecast results of both models coincided in 79% of cases, which indicates the achievement of high indicators of the measure of proximity of forecasts for BSD and MNLR. Both models have shown sufficiently high reliability when verified on empirical data from previous years and can be used as a tool for forecasting. The next stage of the work will be the joint use of BSD and MDR, which can contribute to strengthening the advantages of both approaches and eliminating the shortcomings of some of them.

ASSESSMENT OF THE DEGREE AND SOURCE OF POLYOLEFIN RECYCLATES CONTAMINATION

This study has the aim of analysing the degree of contamination of recycled polyolefin purchased from the market by focusing on the content of polycyclic aromatic hydrocarbons (PAHs). Additionally, the impact of the mechanical recycling process on the polyolefin chemical quality was investigated. Results indicated that recycled polyethylene (PE) had higher PAHs concentrations by 10 to 20 folds in comparison to the pristine PE. Similarly, recycled polypropylene (PP) indicated higher PAHs concentrations in comparison to the virgin polypropylene, yet with lower degree of difference. Analysing the 8 indicators assigned by the Regulation EU 1272/2013 amending REACH Annex XVII, all recycled specimens showed concentrations lower than the limit of 0.5 mg kg-1, which indicates that there is no restriction in material’s utilisation. This study functioned as a preliminary assessment to check the suitability of recycled plastics for their further utilisation. Additionally, the study indicates that polyolefin can experience quality deterioration when uncontrolled recycling conditions are applied.

Environmental Pollution Indices and Multivariate Modeling Approaches for Assessing the Potentially Harmful Elements in Bottom Sediments of Qaroun Lake, Egypt

This research intends to offer a scientific foundation for environmental monitoring and early warning which will aid in the environmental protection management of Qaroun Lake. Qaroun Lake is increasingly influenced by untreated wastewater discharge from many anthropogenic activities, making it vulnerable to pollution. For that, six environmental pollution indices, namely contamination factor (Cf), enrichment factor (EF), geo-accumulation index (Igeo), degree of contamination (Dc), pollution load index (PLI), and potential ecological risk index (RI), were utilized to assess the bottom sediment and to determine the different geo-environmental variables affecting the lake system. Cluster analysis (CA), and principal component analysis (PCA) were used to explore the potential pollution sources of heavy metal. Moreover, the efficiency of partial least-square regression (PLSR) and multiple linear regression (MLR) were tested to assess the Dc, PLI, and RI depending on the selected elements. The sediment samples were carefully collected from 16 locations of Qaroun Lake in two investigated years in 2018 and 2019. Total concentrations of Al, As, Ba, Cd, Co, Cr, Cu, Fe, Ga, Hf, Li, Mg, Mn, Mo, Ni, P, Pb, Sb, Se, Zn, and Zr were quantified using inductively coupled plasma mass spectra (ICP-MS). According to the Cf, EF, and Igeo results, As, Cd, Ga, Hf, P, Sb, Se, and Zr demonstrated significant enrichment in sediment and were derived from anthropogenic sources. According to Dc results, all collected samples were categorized under a very high degree of contamination. Further, the results of RI showed that the lake is at very high ecological risk. Meanwhile, the PLI data indicated 59% of lake was polluted and 41% had PLI < 1. The PLSR and MLR models based on studied elements presented the highest efficiency as alternative approaches to assess the Dc, PLI, and RI of sediments. For examples, the validation (Val.) models presented the best performance of these indices, with R2val = 0.948–0.989 and with model accuracy ACCv = 0.984–0.999 for PLSR, and with R2val = 0.760–0.979 and with ACCv = 0.867–0.984 for MLR. Both models for Dc, PLI, and RI showed that there was no clear overfitting or underfitting between measuring, calibrating, and validating datasets. Finally, the combinations of Cf, EF, Igeo, PLI, Dc, RI, CA, PCA, PLSR, and MLR approaches represent valuable and applicable methods for assessing the risk of potentially harmful elemental contamination in the sediment of Qaroun Lake.

Quantification and analysis of surface macroplastic contamination on arable areas

Purpose The present study provides quantitative data on the degree of macroplastic contamination of two conventionally treated arable areas in North Rhine-Westphalia (Germany), which differ only in the use of organic fertilizers (e.g., compost). Methods The plastic contamination of both areas was determined by means of field sampling. The study areas were divided into edge and central areas to minimize and identify direct influences from the boundaries. After cleaning and drying, the collected macroplastic particles were analyzed by phototechnical and optical methods for number and size of particles. Results The arable area with compost fertilization showed a substantially higher macroplastic pollution with 9247 particles per hectare compared to the 220 particles per hectare found on the arable land without compost application. Furthermore, the differences in plastic forms and types on both areas, the presence of plastic directly related to household and garden products, and the homogeneous distribution of plastic particles on the arable area with compost application allow to conclude that compost can be regarded as reason for substantially higher pollution. Areas close to a road showed a higher degree of contamination and differences in the found plastic products compared to the center areas, which indicates littering as a further considerable entry path. Conclusions The causes of plastic contamination of the investigated arable areas (e.g., contaminated compost by improper waste management and littering) are predominantly external to agricultural practices. The knowledge gained contributes to the knowledge about quantities, impacts, and fate of plastic in the environment.

Groundwater pollution in the Mesta River terrace caused by Eleshnitsa tailings pond – current status

Even after the implementation of eco-protective measures, the Eleshnitsa tailings pond continues to contaminate the Quaternary aquifer, formed in the alluvial deposits of Mesta River. A three-dimensional model of mass transport of selected key pollutants is developed on the basis of hydrochemical studies, geophysical surveys, and processing and systematization of monitoring data. The spread and degree of contamination in the Quaternary aquifer are estimated.

The relevance of topical drugs endaural use in otosurgical practice

Introduction. Preoperative, in particular, antiseptic, preparation of the external auditory canal (EAC) is an important issue for the otosurgeon to take in mind, especially with endaural approach.The aim of the study is to assess the skin microbiota of the EAC and the effectiveness of antiseptic treatment before endaural intervention.Materials and methods. A prospective study including 19 patients who underwent ear surgery by endaural approach: 10 stapedoplasty; 9 tympanoplasty. Ear swabs culture were taken from all the patients preoperatively and after removing the tamponade. Of the 10 patients with otosclerosis, 5 underwent skin preparation with 10% povidone iodine and a swab culture.Results. According to the microbiological examination results, Staphulacoccus Auricularis prevailed in the first smear - 52.6%. In 5 patients with otosclerosis, in comparison to the 1st swab: one case with absence of microorganisms growth, in the other 4 -decrease in the degree of contamination by half. In the 3rd swab, there was no growth in these patients and in the rest, who didn't undergo antiseptic preparation. Patients, without antiseptic preparation of the ear canal, after tympanoplasty (9 patients) in the second smear, had an increase of contamination (from 105 to 106 CFU/ml).Conclusions. Analysis of the microbiome before and after the operation revealed the growth of predominantly (94.7%) opportunistic microorganisms. Preoperative antiseptic preparation reduces the degree of contamination of the skin, which, in our opinion, prevents complications and improves the healing process.

Phytoextraction of Cr(VI)-Contaminated Soil by Phyllostachys pubescens: A Case Study

This work presents the results of experimental tests to evaluate the effects of prolonged contamination by Cr on Moso Bamboo (MB) (Phyllostachys pubescens) and the adaptability of the MB to the Mediterranean climate. A preliminary test on the MB was developed in the laboratory, simulating irrigation under Mediterranean conditions (600 mm per year) and tropical conditions (1800 mm per year), to evaluate the rate of growth and the MB’s capability for Cr phytoextraction from contaminated soil. The tolerance of MB to Cr was also performed showing a good response of the plant to 100 mg Cr/L solution, utilized for irrigation of the pots. The results show that the rate of MB’s removal of Cr from soil ranged from 49.2% to 61.7% as a function of the soil degree of contamination, which varied from approx. 100 mg/kg to 300 mg/kg. The distribution of Cr in the various sections of the bamboo revealed that the greater percentage was present in rhizomes: 42%, equal to 114 mg Cr for 600 mm per year, and 50%, equal to 412 mg Cr for 1800 mm per year. A noteworthy diffusion of the metal towards the outermost parts of the plant was shown. The values of Cr retained in the stems and leaves of MB tissues were quite high and varied from 1100 mg/kg to 1700 mg/kg dry weight.

Health and Ecological Risks Associated with Heavy Metal Contamination in Surface Soils from Lagos Lagoon Wetlands, Lagos, Nigeria

Wetlands quality and spatial distribution are being threatened by anthropogenic drivers in addition to the emerging threats of climate change. In this study, selected heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) in soils from Lagos lagoon wetlands were investigated to assess spatial distribution, ecological and health risks. The data obtained were subjected to statistical analysis using GraphPad 7.0 and SPSS 22.0. Spatial distribution mapping of heavy metals was performed using ArcGIS10.0 (ESRI, Redlands, CA, USA) with Kriging interpolation. Results showed that heavy metals in the soil varied significantly (p<0.05). The contamination factors (CF) were generally low with the values for Cr, Ni, Cu, and Zn very low (<1). The CF values for some of the sampling points showed that the soils are generally moderately contaminated by Pb, Cd and Cu. The modified degree of contamination of Pb (2.35) indicates a moderate degree of contamination while that of Cd (12.60) indicates a high degree of contamination of these wetland soils. The potential ecological risk index (RI) of Pb, Cd, Cr, Ni, Cu and Zn were 70.40, 2264.40, 0.68, 1.55, 13.65, and 2.29, respectively. The RI for Pb, Cr, Ni, Cu and Zn were less than 100, hence, low, while the RI value of Cd was a very high risk (RI ≥ 400). Soils from this wetland’s areas show serious significant potential ecological risk due to Cd. Additionally, children were more susceptible to the potential health risk irrespective of the carcinogenic or non – carcinogenic risk. There were no significant carcinogenic and non – carcinogenic risks for adults and children. This wetland assessment provided important information for policymaking to reduce the potential effects of soil contamination on humans and the eco-environment.

Estimation of Bacterial Contamination on Toothbrush used by Different Students for a Different Time Period

Introduction: Contamination of a surface occurs by microorganisms when it inhabits any surface or an object when the count of the bacteria increases. The degree of contamination can be estimated by counting the number of colonies, when a sample collected from that site is cultured. Streptococcus mutans is considered to be the normal commensal of our oral cavity. When it’s count is increased in the oral cavity, it causes dental caries and other tooth related problems. The main aim of this study is to estimate the bacterial contamination in the tooth brush head used by students for varying time periods. Materials and Methods: Used toothbrushes for varying time periods are collected from students. Then their bristles are plucked with the sterilized forceps for the prevention of bacterial contamination and agitated in the saline and inoculated in the brain heart infusion broth agar with the help of sterilized bacterial loops and incubated for 24 hours at 37oC. Then the colonies are counted and record as CFU/ml. Results: The bacterial count is directly proportional to period of usage, but it is affected by certain factors like duration of brushing and using brushes. On an average the count was estimated to be 47 CFU/ml for two months, 57 CFU/ml for six months, 68 CFU/ml for eight months and 81 CFU/ml for a year. The p1 value (for sample 1 and 2) was 0.046 (p<0.05), so it is statistically significant. Conclusion: The study shows that in prolonged usage of tooth brushes the bacterial contamination also increases. So the tooth brushes should be protected in tooth brush holders, to avoid contamination and the toothbrushes should be changed once in a month for betterment of oral health.

Evaluation of Heavy Metals and Contamination Status of Soil around Abandoned and Active Nigerian Dumpsites

Aim: The study evaluated the heavy metals and contamination status of soil around active and abandoned waste dumpsites in Port Harcourt Metropolis, Nigeria. Methodology: Five soil samples were collected at the topsoil (0-15cm depth) in a regular distance of 20m, 40m, 60m, 80m and 100m from the center of the dumpsites and control plot. The soil samples were analysed for heavy metals (Cu, Cr, Cd, Fe, Pb and Zn), pH and total Organic C (TOC) using standard laboratory analyses and contamination indices to determine the soil contamination status. Descriptive statistics involving mean and standard deviation were used for the data analysis. Results: The mean concentrations of Cu, Cr, Cd, Fe, Pb and Zn in active dumpsite was 3.2616mg/kg, 0.3983 mg/kg, 0.2027 mg/kg, 6.5785 mg/kg, 2.6991mg/kg and 12.4111mg/kg respectively while that of the abandoned dumpsite are 1.3913mg/kg, 0.3693mg/kg, 0.0882mg/kg, 3.6235mg/kg, 0.4158mg/kg and 4.0140mg/kg respectively. Hence, the soil samples in both dumpsites exceeded the allowable limit of World Health Organisation (WHO). The order of heavy metal concentrations in the dumpsites was Zn>Fe>Cu>Pb>Cr>Cd. The contamination factor of the heavy metals follows order: Pb > Cu > Cr > Zn > Fe for both dumpsites. The degree of contamination ranged from (1612.51 to 2286.83 for active dumpsite and 26.14 to 641.46 for abandoned dumpsite) indicating very high degree of contamination. Modified degree of contamination ranged from 46.09 to 381.14 for active dumpsite indicating “ultra-high degree of contamination” and 4.36 to 106.91 for abandoned dumpsite indicating high degree of contamination to ultra-high degree of contamination. Pollution Load Index ranged from (5.08 to 8.12 for active and 1.63 to 4.16 for abandoned dumpsite) indicating polluted soil with various heavy metals. Conclusion: the concentration of heavy metals combined with the contamination indices revealed that the soils around the dumpsites are contaminated/polluted; hence, pose ecological and health-related risk.