Degree Of Pollution Research Articles

Health risk assessment of heavy metal pollution and its sources in agricultural soils near Hongfeng Lake in the mining area of Guizhou Province, China.

Accelerated modern industrial processes, extensive use of pesticides and fertilizers and remaining issues of wastewater irrigation have led to an increasingly severe composite pollution of heavy metals in arable land. Soil contamination can cause significant damage to ecological environments and human health. Mineral resource mining can result in varying degrees of heavy metal pollution in surrounding water systems and soil. As a plateau lake, Hongfeng Lake has a fragile watershed ecosystem. Coupled with the rapid development of the current socio-economy and the ongoing activities of mining, urbanization and agricultural development, the water and soil environment of the lake and arable land are facing serious heavy metal pollution. Therefore, the situation warrants attention. This study focused on characterizing soil types and conducted sampling and laboratory testing on the farmland soil in Hongfeng Lake. The integrated Nemero comprehensive pollution assessment and potential ecological pollution assessment methods were used to evaluate the heavy metal pollution status. The APCS-MLR model was employed to explore the sources of heavy metal pollution. In addition, the human health risk model was used to analyze the association between heavy metal content in cultivated land and human health risks. The single-factor pollution of each element was ranked in descending order: Hg > As > Pb > Cr > Cd, with Hg being the main pollutant factor. The entire area was subjected to mild pollution according to the pollution index. Pollution source analysis indicated two main pollution sources. Hg, As, Pb and Cr pollution mainly resulted from Source 1 (industrial and natural activities), accounting for 71.99%, 51.57%, 67.39% and 68.36%, respectively. Cd pollution was mainly attributed to Source 2 (agricultural pollution source), contributing 84.12%. The health risk assessment model shows that heavy metals posed acceptable carcinogenic risks to humans rather than non-carcinogenic risks. As was the main non-carcinogenic risk factor, while Cr was the main carcinogenic risk factor, with higher risks in children than adults. Our study identified the heavy metal pollution in farmland soil in Hongfeng Lake, evaluated and analyzed the pollution sources and identified the heavy metal elements in cultivated lands that have the greatest impact on human health risks. The aim of this study is to provide a scientific basis for soil heavy metal pollution control.

Study on the Risk Level of Regional Light Pollution Based on the EWM-TOPSIS Model —— A Case Study of China

In recent years, the rapid development of industrialisation has led to serious light pollution problems . In order to measure the degree of regional light pollution, firstly, this paper divides light pollution into three parts: ecological light pollution (Eco), daylight pollution (Dai) and decorative light pollution (Dec), selects nine secondary indicators, assigns a value to each indicator using the entropy weight method (EWM), and the three main indicators are 0.2484, 0.3569 and 0.3947, and combines with the tosis to establish a comprehensive evaluation model. In addition, considering the importance of necessary light, we added three metrics to the original metrics to optimise the model to ensure better safety and comfort.Finally, Applying the model to four specific areas, namely urban, rural, suburban and protected areas, to measure the specific pollution level of the region. Domestic research on light pollution is mainly qualitative research, this paper comprehensively considers the necessity of appropriate amount of light and the harm of excessive light, and proposes a comprehensive evaluation model of light pollution based on the entropy weight method to quantitatively analyse the degree of light pollution. This paper provides a new perspective for light pollution prevention and control.

Status, Source, and Risk Assessment of Heavy Metal(Loid)s and Polycyclic Aromatic Hydrocarbons (PAHs) in the Street Dust of Ilam, Iran

A total of 25 Ilam street dust specimens were sampled to investigate the possible ecological and health risks of heavy metal(loid)s and polycyclic aromatic hydrocarbons (PAHs). We found that the average concentrations of heavy metal(loid)s, namely Pb, Zn, Cu, Cr, Cd, Ni, V, and As, were 52, 213, 63, 46, 0.4, 44, 31, and 5 mg/kg, respectively. The average concentration of all heavy metal(loid)s except for Cr and V was several times higher than the baseline values. We evaluated Zn and Pb in the region using the average enrichment factor (EF) and pollution index (PI); the Nemerow integrated pollution index (NIPI) indicated that 76% of the samples had high degrees of pollution. According to principal component analysis (PCA), three principle components are involved in the heavy metal(loid) pollution of Ilam street dust. For example, the pollution sources of Cu, Cr, Cd, and Ni likely originated from anthropogenetic origins, including traffic, tire depreciation, and gasoline use. The sources of Pb and Zn were other anthropogenic activities, such as metal corroding and the combustion of garbage and gases from industries, while V and As were probably from natural sources. The range of sum over 11 PAHs was 167–11,497 μg/kg with a mean of 2242 μg/kg. The concentration of low molecular weight (LMW) PAHs averaged 1471 μg/kg, accounting for 66% of the total PAHs; their sources were mainly associated with combustion and pyrogenic emissions. The PCA also revealed that PAHs mainly originated from burning fossil fuels. The values of RQ∑PAHs (MPCs) and RQ∑PAHs (NCs) were respectively >1 and ≥800, indicating a high ecosystem risk for PAHs. Mean values for RQ∑PAHs (MPCs) and RQ∑PAHs (NCs) were 4 and 1021, respectively, implying that Ilam street dust poses a relatively high ecosystem risk of PAHs. Street dust PAHs’ toxic equivalency quotient (TEQ) varied from 26 to 199 μg/kg. The total cancer risk was 3.92 × 10−4 and 4.06 × 10−4 for adults and children, respectively, indicating that the potential for cancer risk is very high through dust dermal contact and ingestion.

Analysis and Assessment of the Soil Environment Around a Plateau Municipal Solid Waste Incineration Plant

ABSTRACT To understand the source, distribution and degree of pollution of heavy metals in the soil around a plateau municipal solid waste incineration plant, a municipal solid waste incineration plant in Lhasa was taken as the research object in this study. The soil surrounding the facility was sampled, and the contents of heavy metals, including Cu, Pb, Zn, Cr, Ni, Cd, As, and Hg, in the soil were analyzed. Then, heavy metal pollution and risk assessments were conducted using the geoaccumulation index method, Nemerow index method, and potential ecological risk index method. Additionally, correlation and principal component analysis were used to determine the correlation between heavy metals in the soil and their sources of pollution. The results showed that based on the Nemerow comprehensive pollution index, the soil surrounding the incineration plant generally had a low level of pollution. Through the analysis of individual potential ecological risk indices, it was found that only the heavy metal Cd presented moderate potential risks, while the other seven heavy metals had mild potential risks. The average value of the total potential risk coefficient was 107.31, which was less than 150, indicating that there was a slight potential risk associated with the soil around the incineration plant. There was significant correlation between six heavy metals, namely, Cu, Pb, Zn, Cr, Ni, and Cd, in the soil around the incineration plant. Their pollution sources were similar, and their levels tended to be affected by the incineration plant. However, there was no significant correlation between the heavy metals As and Hg and the other six heavy metals. These two heavy metals had independent sources of pollution but were also influenced by human activities.

Evaluation Heavy Metals Pollution in the Soil from some Regions of Al-Diwaniyah City / Iraq

Soil is the surface layer of the earth’s crust in which plant roots grow and some animals and other microorganisms live in it and it is considered the basis of the ecosystem, so its contamination negatively impact the health of all living organisms, especially humans who are at the top of the food chain. Heavy metals are considered among the most prominent inorganic pollutants in the soil, so this study came to evaluate the concentrations of some toxic heavy metals in areas with different activities in the city of Diwaniyah. The results of the study showed that the concentrations of heavy metals in the surface soil ranged between (0.958-2.292 mg/kg) and (19.132-73.907 mg/kg), (14.882 - 50.012 mg/kg) and (29.689-62.109mg/kg) for cadmium, lead, copper and chromium, respectively, and their concentrations in the soil at depth of 30 cm ranged between (1.529-1.971 mg/kg), (22.160 - 99.885 mg/kg), (12.790-55.630 mg/kg) and (41.278-75.467 mg/kg) for cadmium, lead, copper and chromium, respectively. Soil pollution was evaluated by using some pollution indices such as the geological accumulation index, pollution load index, contamination factor and degree of pollution. The results of pollution indices showed that the surface soil of the surface study sites and depth of 30 cm is contaminated with a very high degree of cadmium. Medium pollution with lead and little pollution with copper and chromium, and this requires great attention in order to reduce soil pollution with heavy metals, especially cadmium and lead.

Application and comparison of four assessment methods for water quality of Sancha Lake in Central Sichuan Province, China

Abstract In order to analyze and compare the characteristics and applicability of different water quality evaluation methods applied to lake water quality evaluation, four monitoring sections were set up in Sancha Lake in 2019, 2020, and 2021, and 20 water quality parameters were selected. The single factor index method, the comprehensive pollution index method, the Nemerow pollution index method, and the improved Nemerow pollution index method were used to comprehensively evaluate water quality. The research results showed that the single factor index evaluation method is simple to operate and can quickly determine the water quality category by identifying the worst single water quality indicator. The comprehensive pollution index method and the Nemerow pollution index method determine the degree of water pollution based on the numerical values representing the overall pollution level of the representative water body. The evaluation results showed that except for the evaluation results of the single factor evaluation method with categories II and III, the results of other evaluation methods were all category I, indicating that the water quality was good.

The Resistance of Waters to Trophy Increases as a Result of Processes in Their Ecotone Areas (according to Phytoplankton Indicators)

According to the saprobity index, estimated by the phytoplankton biomass, the degree of organic pollution of ecotone areas (the mouth of the Il’d River and the littoral of the Volga reach of the Rybinsk reservoir) was determined. The saprobity index in protected shallow waters was 1.83 in 2009 and 2.07 in 2010; in the pelagial – 2.14 and 2.13 in 2009 and 2010 respectively. In the “river-reservoir” system, the lowest average values of the saprobity index were noted in the mouth area of the Il’d River: in 2009 – 1.94, in 2010 – 1.87, in 2011 – 1.88. In the river and the reservoir, its values were higher: 2.05 and 2.07 in 2009, 1.96 and 2.08 in 2010, and 1.97 and 1.99 in 2011 respectively. The decrease in saprobity in shallow waters and at the mouth of the river, compared to the bordering water, indicates a higher intensity of self-purification processes, which can ensure the sustainability of the ecosystem of the reservoir as a whole. Abnormal weather phenomena, in particular, high summer water temperatures, can lead to destabilization of the features of ecotone algocenoses, as a result, to a violation of the process of self-purification of the reservoir.

Extended producer responsibility – tool for sustainable development of tourism in the Republic of Moldova

The purpose of the study is to reveal the importance of the use of sustainable development tools by economic agents in the tourism industry. The object of the study is the extended responsibility of producers for the packaging placed on the market, which is used in the Republic of Moldova as a tool that contributes to sustainable economic development. The author used such research methods as: documentation, analysis, comparison, synthesis, deduction. Concerned by the high degree of pollution that is generated by human activity, in particular, economic activity, most of the world's states have agreed on the need to maintain adequate conditions for life on earth, by establishing the Sustainable Development Goals (SDG). In order to achieve the Sustainable Development Goals, various methods and tools are used, both of a punitive and stimulating nature. One of these tools is "extended producer responsibility". Analyzing the requirements of the legislation regarding the responsibilities of producers for the packaging placed on the market, it is found more efficient and less expensive, respectively, economic agents in the tourism industry are recommended to comply with the requirements of the legislation regarding the prevention, collection and processing of waste by using a collective system, applying the approach "extended producer responsibility".

Revealing the hidden burden for lake management: the sediment phosphorus storage pools in Eastern Plain Lake Zone, China.

As one of the essential components in ecosystems, lakes play a major role in the global phosphorus (P) cycle. It is helpful for further understanding of the inside lake P geochemical cycle to research P pollution and storage in lakes, which is of positive significance for lake eutrophication restoration. In this study, we investigated the total phosphorus concentrations (TPC) of water and sediments from 37 lakes in the Eastern Plain Lake Zone (EPL) of China, evaluated the P pollution degree of lakes, and estimated P storage in lake sediments with quantitative data of lake area and number. The results indicate that the total phosphorus concentrations of water (TPCW) and total phosphorus concentrations of the surface sediments (0-1cm, TPCSS) in EPL were high, the mean values were 0.11mg·L-1 and 869.85mg·kg-1 respectively, with obvious differences between urban and rural areas, as well as between different river basins. Over half (56.76% and 70.27% respectively) of the lakes reached severe pollution levels in water and surface sediments. There were 16224 lakes (> 0.01 km2) with a total area of 21662.37 km2 in the EPL, and the P storage in the lake sediments (0-30cm) was about 4.87 ± 2.08 Tg (1 Tg = 1 × 1012g), accounting for about 2.74% of the basin soil. TPCW and TPCSS of lakes in the EPL were significantly positively correlated, may suggest a close nutrient cycling relationship between the lake water and the sediment. During periods of high winds and waves, the stored P in the top sediments in the EPL may continue to participate in the internal P geochemical cycle and migrate to the overlying water, posing a potential pollution hazard. Therefore, it is crucial to take into account the sediment P pools when formulating effective lake phosphorus management strategies.

The impacts of artificial light at night on the ecology of temperate and tropical reefs.

Despite 22% of the world's coastal regions experiencing some degree of light pollution, and biologically important artificial light at night (ALAN) reaching large portions of the seafloor (greater than 75%) near coastal developments, the impacts of ALAN on temperate and tropical reefs are still relatively unknown. Because many reef species have evolved in response to low-light nocturnal environments, consistent daily, lunar, and seasonal light cycles, and distinct light spectra, these impacts are likely to be profound. Recent studies have found ALAN can decrease reproductive success of fishes, alter predation rates of invertebrates and fishes, and impact the physiology and biochemistry of reef-building corals. In this paper, we integrate knowledge of the role of natural light in temperate and tropical reefs with a synthesis of the current literature on the impacts of ALAN on reef organisms to explore potential changes at the system level in reef communities exposed to ALAN. Specifically, we identify the direct impacts of ALAN on individual organisms and flow on effects for reef communities, and present potential scenarios where ALAN could significantly alter system-level dynamics, possibly even creating novel ecosystems. Lastly, we highlight large knowledge gaps in our understanding of the overall impact of ALAN on reef systems. This article is part of the theme issue 'Light pollution in complex ecological systems'.

Effect of water stratification and mixing on phytoplankton functional groups: a case study of Xikeng Reservoir, China

A shift in reservoir stratification and mixing significantly affects the water column ecosystem, which in turn leads to changes in phytoplankton abundance and community structure. To explore the effects of stratification and mixing on the phytoplankton community structure of a diversion reservoir, a 1-year survey was divided into a stratification period in 2020, a mixing period in 2020, and a stratification period in 2021, and redundancy analysis (RDA), variance partitioning analysis (VPA) and Pearson correlation analysis were used to analyse the key drivers affecting the phytoplankton functional groups, using Xikeng Reservoir as a case study. During the study period, 8 phyla, 69 genera and 9 major functional groups were observed in this reservoir. The dominant functional groups varied significantly, being X1 in the stratified period in 2020; P and D in the mixing period in 2020; and D, X1, and M in the stratified period in 2021. The phytoplankton diversity index was greater in the mixing period than in the stratification period, in agreement with the results of the aquatic ecological status evaluation (Q index, higher in the mixing period than in the stratification period). However, phytoplankton diversity of Xikeng Reservoir was of limited value in assessing the degree of water pollution, so should be considered in combination with the Q index. Water temperature (WT), mixing depth (Zmix), nitrogen–phosphorus ratio (N/P), and total nitrogen (TN) were important drivers of phytoplankton functional group dynamics in different periods. The study provides a valuable reference for assessing the relationship between environmental factors and phytoplankton communities, as well as for the evaluation and conservation of aquatic ecosystems in southern China's water diversion reservoirs.

Spectrophotometric determination of COD based on synergistic photocatalysis redox reaction using titanium dioxide nanoparticles and phosphomolybdic heteropoly acid

Chemical oxygen demand (COD) is one of the important indicators to measure the degree of organic pollution in water. In this work, a rapid spectrophotometric method for detection of COD was achieved based on the oxidation of organics in water by photogenerated holes or free radicals and the reduction of phosphomolybdic heteropolyacid by photogenerated electrons by using TiO2 nanoparticles as a photocatalyst. Taking potassium hydrogen phthalate as the COD standard, under the optimal conditions, the absorbance of reduced phosphomolybdic heteropoly acid was linear with COD in the range of 0.50–100 mg L −1. The detection limit for was COD detection was 0.171 mg L −1. The proposed methods was used for the determination of COD in real water samples, and the results were in general agreement with the national standard method. Compared with the direct photo initiated reduction of phosphomolybdic heteropoly acid without TiO2 nanoparticles, the photocatalytic reaction has better stability and higher efficiency.

Air pollution and topography in Tehran

Tehran is one of the most polluted cities in the world with 48 days of air pollution exceeding the admissible threshold (AQI > 150) for 3 months of the 15 years studied. This period coincides with the time when Tehran’s inversion reaches its maximum stability. The purpose of this study was to determine the height of air pollution in Tehran in the days when pollution exceeds the permissible limit. Continuing to study the pressure and temperature conditions of these days, we then considered the geographical and topographic conditions, and finally identified the best of these cells for potential theoretical air turbulence. The results of this study, based on the Harmonic Analysis method and based on Tehran temperature and pressure data over a 15-year period (2003–2017), show that the highest elevation of Tehran inversion does not exceed 1800 m on polluted days. Only within 6 days of those beyond the admissible threshold, temperature and pressure cells with the highest Newtonian mass are formed. The center of these cells formed with a compressive difference of 32 mg in November, 7 mg in January, 11 mg in December, and temperature difference of 1.1° in November, 4.4° in January, and 1.9° in December. Generally, we considered the formed cells by the temperature and pressure difference and the gradient between them, as well as the difference in height between the cells and their location. This information, combined with the local winds causing the differences in temperature and pressure, allows us to elucidate conditions for creating air turbulence in Tehran and mitigating the amount and degree of air pollution.

Significant Dynamic Disturbance of Water Environment Quality in Urban Rivers Flowing through Industrial Areas

The urban water environment is seriously affected by human activities. Rivers in highly industrialized areas, which often carry various types of industrial pollutants, such as metals and nutrients, are especially affected. In this study, the water quality of the Pi River, an industrial base that flows through Chengdu, a large city in Southwest China, was tested for one year. Heavy metal concentrations in the water, sediment, and macrobenthic and algal communities in the river were examined. The water pollution index (WPI) and trophic level index (TLI) were employed to measure the water pollution degree and eutrophication status, respectively. The Shannon—Wiener index (H’) and Margalef’s index (dM) were determined to represent the diversity and richness of macroinvertebrates. The principal component analysis (PCA) was employed to define the main heavy metal influencing factors in the Pi River. Our study showed that the eutrophication status increased with spatial change, and the eutrophication status was the most serious in the downstream reach, which was moderately eutrophic. The water body of the Pi River was seriously polluted by heavy metals, and the content of chromium (Cr) in the sediment and cadmium (Cd) in the water/sediment was far beyond the prescribed limit. In addition, we found that Cd had a serious impact on both the benthic and algal communities, and the benthic community structure was completely changed, destroying the original aquatic environment. We explored the mechanisms of the influence of Cd on aquatic fauna, and this information is of great significance for the future conservation of industrial urban rivers. In this study, the spatial–temporal variations in water quality and aquatic communities revealed the pollution status of a river flowing through industrial areas, which provided a basis for future river conservation and restoration.

Concentration, Spatial Distribution, and Source Analysis of Trace Elements in the Yarlung Zangbo River Basin and Its Two Tributaries

The Yarlung Zangbo River (YZR) is the longest plateau river in China and has famous tributaries, the Lhasa River and the Nianchu River. A total of 75 water samples were collected from the Yarlung Zangbo River Basin (YZRB) in this study to investigate the dissolved concentration, spatial distribution, and source of trace elements (Fe, V, Be, Ti, Mo, Se, Cd, Zn, Cu, Ni, Co, Mn, Cr, Ba, Tl, Pb, Hg, As, and Sb). The results indicate that only Cr and Tl contaminate water, while the other trace elements were in an unpolluted state. In addition, correlation analysis showed that there was a highly significant positive correlation between the concentrations of As, Sb, and Mo; there was also a highly significant positive correlation between the concentrations of Fe, Mn, Ti, Pb, Ni, Co, and Ba. The results of Positive Matrix Factorization (PMF) showed that there were four sources of trace elements in the YZRB, including the resuspension and dissolution of sediments (16.283%), agricultural source (11.436%), lithological source (47.418%), and soil-forming rocks (6.374%). Cluster analysis combined with PMF normalized contribution analysis, which showed that the trace elements found in the YZR’s mainstream were predominantly influenced by the surrounding rocks composition. Meanwhile, both the discharge of mining wastewater and sediments were marked in the Lhasa River. Additionally, agricultural activities were the chief contributors to the trace elements in the Nianchu River. Furthermore, the entire basin was subjected to the influence of soil-forming rocks. This study comprehensively analyzed and evaluated the physicochemical properties of water, the spatial distribution, and the pollution degree, and performed source analysis of trace elements in the YZRB. This research provides a foundational reference for further investigation of the spatial distribution and origins of trace elements in the rivers of the Qinghai–Tibet Plateau (QTP).

Mineral magnetic proxies for evaluation of anthropogenic pollution at children's playgrounds – a case study from Sofia city

Quality of the urban environment where children play is of great concern for protecting their health. Thus, fast and economically feasible proxy methods for assessment of urban environment are increasingly applied. In this study, settled dust from 13 playgrounds from Sofia city (Bulgaria), was investigated by mineral magnetism, portable X-ray fluorescence measurements, and scanning electron microscopy. The aim of the study was to evaluate the degree of anthropogenic pollution of playgrounds during winter and summer seasons and to identify pollution sources. Magnetic susceptibility (χ) was measured for two dust fractions - very coarse (grain sizes between 1 and 2 mm) and size fraction of d < 1 mm. In spite of this rough separation, systematic seasonal difference in χ of the two fractions is observed. Winter dust, containing larger amount of finer fraction shows lower χ. Regardless of lower relative content of d < 1 mm fraction, summer playground dusts are more strongly magnetic. Complex Pollution Load Index (PLI), calculated using contents of Cu, Zn, S, Pb (Potentially Toxic Elements (PTE)), shows higher contamination in summer dust, compared to winter. Anhysteretic and isothermal remanences of dust d < 1 mm demonstrate prevailing magnetically stable grains at playgrounds located at greater distance from major boulevards. Thermomagnetic analyses of magnetic susceptibility identified magnetite as the main magnetic mineral, although metallic iron was also evident in summer dust. Based on the meteorological models of atmospheric circulation over Sofia, the pollution sources suggested in a previous research, on one hand, and the carried out Factor Analysis, on the other hand, the results point out that in spite of higher PM10 dust load in winter, summer dust pollution causes stronger PTEs contamination. Factor analysis revealed four factors, explaining most of variability in the data. These factors were identified as: 1) re-suspension of soil and road dust; 2) fine particles magnetite of stable single domain grain size, originating probably from traffic exhaust and non-exhaust emissions; 3) emissions from installations burning waste materials; 4) coal burning.

Functionalized-Graphene Field Effect Transistor-Based Biosensor for Ultrasensitive and Label-Free Detection of β-Galactosidase Produced by Escherichia coli.

The detection of β-galactosidase (β-gal) activity produced by Escherichia coli (E. coli) can quickly analyze the pollution degree of seawater bodies in bathing and fishing grounds to avoid large-scale outbreaks of water pollution. Here, a functionalized biosensor based on graphene-based field effect transistor (GFET) modified with heat-denatured casein was developed for the ultrasensitive and label-free detection of the β-gal produced by E. coli in real water samples. The heat-denatured casein coated on the graphene surface, as a probe linker and blocker, plays an important role in fabricating GEFT biosensor. The GFET biosensor response to the β-gal produced by E. coli has a wide concentration dynamic range spanning nine orders of magnitude, in a concentration range of 1 fg·mL-1-100 ng·mL-1, with a limit of detection (LOD) 0.187 fg·mL-1 (1.61 aM). In addition to its attomole sensitivity, the GFET biosensor selectively recognized the β-gal in the water sample and showed good selectivity. Importantly, the detection process of the β-gal produced by E. coli can be completed by a straightforward one-step specific immune recognition reaction. These results demonstrated the usefulness of the approach, meeting environmental monitoring requirements for future use.

XANTHOPHYLL CONCENTRATION IN LYMNAEA STAGNALIS CAUSED BY CHROMIUM IONS

Currently the pollution of natural waters by heavy metal ions is a particularly serious problem which results in the disruption of the balance of food chains and the overall ecosystem balance. In this regard the study of the reaction of the biotic components of the hydroecosystem to toxic effects is relevant, and will allow to expand the understanding of the adaptive mechanisms of aquatic organisms and to determine sensitive test objects and test functions for assessing the degree of pollution of natural waters.&#x0D; The influence of chromium ions (Cr3+ and Cr2O72-) in concentrations corresponding to 0.5 and 2 TLV in fish farming water basins was studied based on the concentration of xanthophylls in hemolymph, hepatopancreas, mantle and leg of Lymnaea stagnalis, which is a permanent component of most hydrobiocenoses of Zhytomyr Polissia. The dynamics of the discussed carotenoids at different durations of exposure (2, 7, 14 and 21 days) of the studied shellfish in a toxic environment were observed.&#x0D; It was found that 48-hour exposure of shellfish in solutions of chromium ions (Cr3+ and Cr2O72- ) regardless of their concentration (0.5 and 2 TLV) causes 2.45–3.23 times increase of xanthophylls in all the studied organs and tissues of L. stagnalis (p ≤ 0.001) which indicates the development of an immediate reaction of animals to toxic elements. Further prolongation of exposure to chromium ions (7, 14, and 21 days) resulted in non-linear organ-dependent dynamics of the xanthophyll content which is related to the specificity of the action of ions, the duration of exposure of animals to toxic solutions, and the metabolic features of the studied organs and tissues. It is shown that the content of xanthophylls in the body of L. stagnalis is characterized by tissue-organ specificity. The minimum amounts of the discussed carotenoid were recorded in the hemolymph of animals and the maximum values varied significantly between the studied components depending on the experimental conditions.

Characteristics of Cadmium Concentration and Transport of Pueraria thornsonii in Farmland with Different Cadmium Pollution Degrees

This study aimed to elucidate the cadmium (Cd) concentration and transport characteristics of Pueraria thornsonii in farmland with different Cd pollution degrees, so as to provide a reference basis for phytoremediation of Cd-contaminated farmland. The multi-point experiments in farmland with different Cd pollution degrees[ω(Cd) 0.32-38.08 mg·kg-1] were conducted, and the biomass (dry weight), Cd content, accumulation, concentration, and transport of Cd in P. thornsonii tissues under the main growing period were assessed. According to the results, for P. thornsonii, the tuber dry weight ranged from 5.04 to 11.98 t·hm-2, biomass ranged from 13.21 to 29.07 t·hm-2, and Cd accumulation ranged from 15.74 to 106.03 g·hm-2in the study area. The pattern of Cd uptake by P. thornsonii showed that the main vine>leaf>lateral branches>basal part of sti>tuber. The Cd content in P. thornsonii tissues considerably increased with soil Cd content (P<0.05), whereas the biomass decreased significantly (P<0.05). The Cd concentration and transport factor of aboveground parts in P. thornsonii showed a trend of initially falling, then increasing and decreasing again, whereas the Cd enrichment and transport coefficient of tubers gradually decreased. Correlation analysis revealed that the amount of Cd in the soil was a major predictor of Cd accumulation in P. thornsonii. Under light to moderate Cd contamination, the commercial portion of P. thornsonii (arrowroot)[ω(Cd) 0.03-0.22 mg·kg-1] was less than the standard limit for medicinal plants (≤ 0.30 mg·kg-1). In P. thornsonii from moderately contaminated areas, the Cd concentration and transport factor of aboveground parts were 2.43-7.97 and 3.02-9.81, respectively. This indicates that P. thornsonii is a prospective plant ideal for remediating Cd-contaminated soil because of its high capacity to transfer and enrich Cd.

Source Apportionment and Potential Ecological Risk Assessment of Soil Heavy Metals in Typical Industrial and Mining Towns in North China

To understand the status of heavy metals in soils of typical industrial and mining towns and quantitatively analyze the potential sources, the contents of seven heavy metals (Cd, As, Pb, Cr, Cu, Ni, and Zn) in 150 surface soils in Xuanhua District, Zhangjiakou City, Hebei Province were collected and examined. The geoaccumulation index and potential ecological risk index methods were used to evaluate the heavy metal pollution status and potential ecological risk. Principal component analysis (PCA) and the positive matrix factorization (PMF) model were used to comprehensively analyze the pollution sources of seven heavy metals, and geostatistics was used to identify the high contribution areas of potential sources. The results revealed that:① the average values of heavy metals in the study area ranged from 0.23-103.34 mg·kg-1, among which the average contents of Cd, Pb, Cu, and Zn were higher than the soil background value of Hebei Province. ② The results of the geoaccumulation and potential ecological risk indices demonstrated that the degree of pollution of the seven heavy metals was in the following order:Cd>Pb>Cu>Zn>Ni>As>Cr, the content of Cd in 16% sites was above a moderate pollution level, and the potential ecological risk of heavy metals in more than 95% sites was at a light risk level. ③ The main sources of accumulation of the seven heavy metals in the study area were combined sources of industry and traffic, natural sources, and agricultural sources, with their contribution rates of 33.1%, 48.7%, and 18.2%, respectively. Among them, Cd, Pb, Cu, and Zn were primarily affected by the combined sources of industry and transportation; Cr, Ni, and As were mainly affected by natural sources, whereas Cd and some As were affected by agricultural sources. The organic combination of PCA, PMF model, and geostatistical methods confirmed the results of each analysis, which increased the reliability of the analytical results of heavy metal sources.