Moderate Pollution Research Articles

Hydropower development in the Himalaya: identifying critical river stretches.

Two hydroelectric projects are operational in the upper and lower stretches of the river Alaknanda near Lambagarh and Srinagar that are respectively ~ 140km apart. The health of the river ecosystem in the flowing stretches between and below these projects was bio-assessed, based on widely used diatom indices and van Dam ecologic values computed by OMNIDIA software. Samples were collected from Birahi (S3), the semi-natural stretch ~ 53km downstream of the powerhouse, Narkota (S5), the impacted stretch ~27km upstream Srinagar dam and Bagwan (S8), the highly regulated stretch ~22km downstream Srinagar. IPS and IBD revealed mild pollution in the upper and lower stretch compared to relatively elevated pollution at S5. However, TDI indicates moderate organic pollution at S3 and S5, whereas the IDS/E indicates low degradation at all stations. The prevalence of tolerant N-autotroph, β-mesosprobe, mesotrophic, and aquatic to aerophilic categories of van Dam environmental variables indicate that a certain level of impact already persists due to organic-cum-nutrient load and perturbed flow regime. The prevalence of eutrophic and moderate O2 categories shows that the ecosystem is in a critical state at S5, as also observed for species diversity. Based on the dominant categories, the river stretch was classified as "polyoxybiontic-cum-mesotrophic" at S3 and S8 while "moderate O2-cum-eutrophic" at S5, implying higher organic and nutrient load in the river section at S5.

The natural food base of the ponds in Noginsky district of Moscow region

The purpose of this work was to study the natural food base of the ponds in the Noginsk district of the Moscow region in October-November 2022. The selection of hydrobiological materials was carried out in October-November 2022. The pond №1 is a main pond of the EPB of RRIFF, a branch of the FSBSI FRC RIAH named after L.K. Ernst, with an area of 4,48 ha, fertilized with goose and duck droppings. Pond № 2 is ownerless, with peat soil, with an area of about 21,27 hectares. From a fishery point of view, the state of phytoplankton turned out to be more favorable in the ownerless pond. The biomass of phytoplankton in this pond is higher, it is formed mainly by green algae, consumed by both juvenile fish and planktonic organisms, through which the primary production is transferred to the higher levels of trophic pyramid. In the pond № 1, the biomass is much lower and in many respects formed by low-edible blue-green algae. The species diversity of the zooplankton in the EPB RRIFF pond, fertilized with waterfowl droppings, is significantly higher than in the big ownerless pond. The zooplankton biomass here is more than 2 times higher. The number of zooplankton is 1,34 times higher. The percentage of oligochaetes in the benthic invertebrate communities samples from the pond № 1 (68%) indicates moderate water pollution in October-November 2022 with organic matter. Thus, the head pond of the EPB RRIFF, fertilized with waterfowl droppings (the integrated technologies), demonstrated for the benthic invertebrate communities the best indicators of the natural food base state, both in general and in terms of indicators of the individual taxons. The components of the natural food base, which are crucial for the fish nutrition: phytoplankton and benthic invertebrate communities, turned out to be higher in October-November 2022 in the EPB RRIFF pond, fertilized with waterfowl droppings. However, the indicators of phytoplankton were better in the ownerless pond of the Noginsk district of the Moscow region. One of the reasons for the less favorable state of phytoplankton in the EPB RRIFF pond may be the eating of green algae by zooplankton.

Source-oriented probabilistic health risk assessment of soil potentially toxic elements in a typical mining city.

Identifying potential sources of soil potentially toxic elements (PTEs) and developing source-oriented health risk assessments in typical mining cities are key for pollution prevention and risk management. To this end, a case study was conducted to explore the pollution characteristics, potential sources, and human health risks of PTEs in Daye City, China. Indices, including the pollution factor (PF), pollution load index (PLI), and geo-accumulation index (Igeo), were applied to assess PTE pollution. Cd had the highest value among the detected PTEs, and 82.93% of the sampling sites had moderate pollution levels, with the highest mean Igeo value for Cd (2.30). Four potential sources were determined. Cr and Ni originated mainly from natural sources. Zn (91.5%) was exclusively and then Cd (33.1%) was moderately derived from industrial activities. The mixed source of various mineral exploitation smelting, and coal-fired traffic emissions leaded to the accumulation of As, Cd, and Pb. Cu was associated with Cu-related mining and smelting activities. The probabilistic health risk assessment indicated that the non-carcinogenic risks for populations were negligible. Overall, this work provides scientific information for environmental managers to manage soil PTE pollution through the effective management of anthropogenic sources with limited resources and costs.

Combining spatial autocorrelation with artificial intelligence models to estimate spatial distribution and risks of heavy metal pollution in agricultural soils

Information on spatial distribution and potential sources of heavy metals in agricultural lands is very important for human health and food safety. In this study, pollution degree of lead (Pb), cadmium (Cd), and nickel (Ni) in Yüksekova Plain, located on the border in the southeastern part of Turkey, was evaluated by geoaccumulation index (Igeo), modified contamination factor (mCdeg), and Nemerow pollution index (PINemerow) combined with spatial autocorrelation using deep learning algorithms. A total of 304 soil samples were collected from two different depths (0-20 and 20-40cm) in the study area, which covered 17.5 thousand ha land. Covariates were determined for spatial distribution models of Pb, Cd, and Ni by factor analysis (FA). Spatial distribution models for surface soils were developed using pedovariables (silt, sand, clay lime, organic matter, electrical conductivity, pH, Ca, and Na) determined by the FA and Igeo and mCdeg values by artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) models. The estimation success of models for different depths was assessed by root mean square error (RMSE), mean absolute percent error (MAPE), and Taylor diagrams. The RMSE and MAPE values showed a strong correlation between heavy metal contents and the covariates. The RMSE values of ANN-Ni0-20, ANN-Ni20-40, ANN-Pb0-20, ANN-Cd0-20, and ANN-Cd20-40 models (0.01240, 0.07257, 0.0039, 0.00045, 0.00044, and 0.04607, respectively) confirmed the success of the models. Likewise, the MAPE values between 0.2 and 8.5% indicated that all models were very good predictors. In addition, the Taylor diagrams showed that the estimation performance of ANFIS and ANN models are compatible. The IgeoNi and IgeoPb values in both models at both depths indicated that strongly to extremely polluted (4-5) areas are quite high in the study area, while the IgeoCd values revealed that unpolluted areas are widespread. The mCdeg index value showed a moderate to high contamination at the first depth, while very high contamination at the second depth in most of the study area. Spatial distribution of PINemerow revealed that moderate pollution (2-3) is common in both soil depths of the study area. The PINemerow of subsurface layer was between 0.91 and 1 (warning limit class) in a small part of the study area. The results showed that vertical mobility of heavy metals is closely related to pedovariables. In addition, the ANN and ANFIS models are capable of exhibiting the heterogeneity in the spatial distribution pattern of high variation in the data. Thus, the locations with extreme contamination have been accurately determined. The pollution indices calculated considering the commonly used international reference values revealed that heavy metal pollution in some part of the study area reached the detrimental levels for human health and food safety. The results suggested that the pollution indices were more successful than simple heavy metal concentrations in interpreting the pollution risk levels. High-resolution spatial information reported in this study can help policy makers and authorities to reduce heavy metal emissions of pollutants or, if possible, to eliminate the pollution.

Sediment quality assessment in an industrialized Greek coastal marine area (western Saronikos Gulf)

Abstract. Eight sediment cores from the coastal marine area of the western Saronikos Gulf have been analysed for grain size and geochemistry. The concentrations of eight metals (Al, Fe, Mn, Cu, Cr, Ni, Pb and Zn) were measured along with total organic carbon (TOC) and carbonate content. The cores are fairly homogeneous in terms of carbonates and the downcore variability of TOC percentage (% TOC) and are characterized by high surficial values that decrease with depth. Metal concentrations from both geological (Al, Mn, Cr, Ni) and anthropogenic origin (Cu, Pb, Zn) are higher in the muddy fraction than in the sand fraction of sediments. The spatial distribution of Al, Fe, Mn, Cu, Pb and Zn in surface sediments presents increasing concentrations from the northeast to the southwest part of the study area and from the shallow to the deeper parts in contrast to Cr and Ni, which are increased in the northern nearshore stations. Based on the vertical distributions, the metal to Al ratios of Cu, Pb and Zn show a constant decrease over depth along most cores, indicating the anthropogenic effects to surface sediments, while Fe/Al is constant. Spearman's correlation analysis performed among the fine-grain metal contents demonstrated a strong positive correlation (r>0.5, p<0.05) between Al, Fe, Mn, Cu, Pb and Zn. The calculated enrichment factors indicate minimal to moderate pollution. The concentrations of Cr at most surface sediments are higher than the “effects range low” (ERL) value (81 mg kg−1) but below the “effects range median” (ERM) value (370 mg kg−1), and the concentrations of Ni are always higher than the ERM value (51.6 mg kg−1). In contrast, the concentrations of Cu, Pb and Zn at most surface sediments are below ERL values. The mean effects range medium quotients (mERMq) of surface sediments, based on the overall metal concentrations, indicated that the surface sediments of most cores are moderately toxic. The levels of Cr, Ni, Mn and Zn at most stations are decreased in 2017, but the concentrations of Pb and Cu are increased in 2017, compared to a previous study of 2007. The concentrations of Cu, Pb and Zn in the surface sediments of the western Saronikos Gulf are lower than levels reported for the inner Saronikos Gulf, Elefsis Bay and other polluted hotspot areas in Greece, owing to a lower degree of urban and industrial development.

Characteristics of Ozone Pollution and High-impact Meteorological Factors in Urban Cities: A Case of Suzhou

The problem of urban ozone (O3) pollution has become prominent in recent years. However, the meteorological factors associated with O3 pollution remain unclear. Analyzing the characteristics of O3 pollution in Suzhou, as a typical urban city, and exploring the high-impact meteorological factors with O3 pollution are crucial to the prevention and control of air pollution in this region. This study used correlation analysis and machine learning methods to analyze the variation in O3 concentration and the relationship between meteorological driving factors in Suzhou based on the O3 concentration data provided by Suzhou Environmental Monitoring Center and the contemporaneous meteorological observation data in Suzhou from April to September in 2015 to 2020. The results showed that: ① O3 pollution exceeding the standard rate was more than 20% in ozone seasons during the past six years; further, pollution days of O3 and the number of pollution days of O3 as the primary pollutant increased yearly. Evidently, the problem of O3 pollution has become increasingly prominent. ② The diurnal variations in O3 were unimodal with the valley point at 07:00 and the highest peak between 15:00 and 16:00. Similar trends were found in diurnal variations of both air temperature and solar radiation, but the daily highest peak came earlier than that of O3. The results also showed an apparent weekend effect of O3 concentration in 2017 and 2019 and a significant correlation between O3 concentration and solar irradiance during the week. In addition, the monthly variation in O3 concentration and pollution exceeding the standard rate was bimodal. ③The occurrence of ozone pollution was affected by various meteorological conditions. The maximum number of days appeared when daily sunshine hours lasted longer than 7 hours, with a daily maximum air temperature around 30℃, solar irradiance ranging from 350 to 440 kW·m-2, and relative humidity ranging from 50% to 75%, at which time the intensity of pollution was the strongest. When the wind speed of easterly wind was less than 1.5 m·s-1, or the wind speed of southwest wind was less than 3.5 m·s-1, moderate ozone pollution occurred. ④ An optimal prediction model of O3 concentration was established based on machine learning, which had good predictive ability for O3 concentration in April, May, July, and September but did not perform well when O3 concentration exceeded 200 μg·m-3. Meanwhile, it was found that solar radiation had the most obvious effect on O3 concentration, followed by relative humidity, whereas the temperature and wind were less important than the former two factors.

Distribution Characteristics and Pollution Risk of Heavy Metals in River Sediment of Suzhou Water Network Area, China

The average contents of the heavy metals Cd, Cu, Cr, As, Ni, Pb, and Zn in the sediment of sampling points in the Suzhou water network area were 1.4, 127.4, 83.2, 18.2, 51.7, 145.1, and 350.7 mg·kg-1, respectively, which were 13.7, 5.7, 1.1, 1.7, 1.9, 5.5, and 5.6 times the background values, respectively. The proportions of points exceeding the risk screening values of the GB 15618-2018 standard were 100.0%, 97.3%, 38.4%, 83.6%, 97.3%, 90.4%, and 100.0%, respectively. The pollution degree of single heavy metal elements was evaluated using the improved ground accumulation index method. The pollution degree of the seven heavy metal elements in the sediment of the Suzhou water network area was in the order of Cd>Cu>Pb>Zn>As>Cr>Ni. Among them, Cd showed extremely strong pollution, Cu and Pb showed intense to extremely strong pollution, Zn showed strong pollution, As showed moderate to intense pollution, and Cr and Ni showed moderate pollution. Cd, Pb, Cu, and Zn in the sediment samples of the ancient city area, northwest area, southwest area, and east area were the heavy metal elements with high pollution contributions. The potential ecological risk degree of heavy metals was ranked as northwest>southwest>ancient city area>east. Correlation analysis and principal component analysis showed that Cd, Cu, Cr, As, Ni, Pb, and Zn may have come from anthropogenic factors such as tail gas emissions, the use of chemical fertilizers and pesticides, and the pollutant emissions of the electronic manufacturing industry.

Distribution, source, risk and phytoremediation of polycyclic aromatic hydrocarbons (PAHs) in typical urban landscape waters recharged by reclaimed water

A park that had used reclaimed water as the sole water supply for fourteen years, was selected to analyze the distribution, sources and risks of 16 priority polycyclic aromatic hydrocarbons (PAHs) in waters and sediments. The effects of phytoremediation were investigated in waterbodies classified as phytoremediation, transitional and non-phytoremediation areas. Diagnostic ratio (DR) and principal component analysis (PCA) were used to analyze the sources of PAHs, while risk quotient (RQ) was used as risk assessment tool. Results showed that ∑PAH concentrations in sediments ranged from 29.4 to 1245.6 ng‧g−1, with average of 354.3 ng‧g−1, corresponding to a moderate pollution level. The concentration of PAHs in water ranged from 10.6 to 326.3 ng‧L−1, with average of 147.2 ng‧L−1, corresponding to a low pollution level. The ∑PAHs in sediments showed a downward trend from northwest to southeast along with the water flow direction, with average values of 459.5, 362.9 and 246.1 ng‧L−1 in the upstream, midstream and downstream, respectively. In contrast, PAH concentrations in water were consistent with recreational activities in the urban park area. There were 95% of water samples and 72% of sediment samples obtaining the Ant/(Ant + Phe) > 0.1 and Flu/(Flu + Pyr) > 0.5, indicating that coal combustion was the major source of PAHs in both the water and sediment. The RQ∑PAH(NCs) values in water and sediment were all between 1 and 800, while RQ∑PAH(MPCs) reached equal to 0, suggesting that ∑PAHs presented a low ecological risk. Acenaphthene accounted for 28.4% of RQ(NCs), and became the most risk PAH in water column. Aquatic plants effectively removed high-ring PAHs from water and middle-ring PAHs from sediments, reducing the overall risks posed by PAHs.

Objective identification and forecast method of PM2.5 pollution based on medium- and long-term ensemble forecasts in Beijing-Tianjin-Hebei region and its surrounding areas

Accurate long-term forecasts of PM2.5 pollution are essential to mitigating health risks and formulating pollutant control strategies for decision-makers in China. In this study, an objective identification and forecast method for PM2.5 pollution (OIF-PM2.5) is developed based on medium- and long-term ensemble forecasts of PM2.5 in Beijing-Tianjin-Hebei region and its surrounding areas. The results show that the observed PM2.5 pollution ratio increases with the aggravating PM2.5 pollution. For example, the ratio of meteorological stations with heavy pollution is 4.4 times that of light pollution and 3.9 times that of moderate pollution. In addition, the correlation coefficients between observations and forecasts are above 0.60 for all forecast leading times. Statistical results show that the average accuracy for forecasts with the leading times of 1–3 days, 4–7 days, and 8–15 days are 74.1%, 81.3%, and 72.9% respectively, indicating that the OIF-PM2.5 method has a high reliability in forecasts with the leading times of 1–15 days. The OIF-PM2.5 method is further applied in a severe PM2.5 pollution episode in the December of 2021, and the average forecast precision in forecasts with the leading times of 6–8 days reaches as high as 100%, showing a certain reference value for PM2.5 forecasts.

Heavy metal pollution in surface sediments and human health assessment in southern Al-Khobar coast, Saudi Arabia

Surface sediment samples from twenty-nine stations in south Al-Khobar coastline, Arabian Gulf, have been examined to assess the heavy metal contamination and impact on human health through dermal contact. The content in Cu, Zn, Cd, Pb, Fe, Mn, Co, Hg and Ni, was evaluated. Pollution index, modified degree of contamination, and pollution load index agreed to exclude heavy metal pollution. Differently, soil pollution index and Nemerow integrated pollution index pointed out moderate and heavy pollution grade for Hg and Cu, respectively. The human health assessment, according to the low values of the hazard index ˂ 1.0 for both adults and children, excluded any significant impact on the human body. The chronic daily intake and the total lifetime cancer risk also were consistent in excluding any risk to human health. Similarly, the carcinogenic risks for Pb and Cd, and the total cancer risk ˂1 × 10−6, did not imply significant health hazards.

БИОИНДИКАЦИОННАЯ ЗНАЧИМОСТЬ ТАКСОНОМИЧЕСКИХ И СТРУКТУРНЫХ ПОКАЗАТЕЛЕЙ АЛЬГОЦЕНОЗОВ МАЛОЙ РЕКИ ПРИ ОЦЕНКЕ ТОЧЕЧНОГО ИСТОЧНИКА АНТРОПОГЕННОГО ВОЗДЕЙСТВИЯ

Phytoplankton studies were carried out in a small river (the Usa River, the Kuibyshev Reservoir basin) in the area affected by a point source of pollution. Comparative analysis revealed a change in the structure of phytoplankton in the wastewater discharge zone of the village of Shigony (Samara region). An increase in the saprobity index, a variety of species-indicators of an increased degree of saprobity, as well as an increase in the role of small-celled species in the community in this area are shown. At the same time, the species diversity at the discharge site and downstream is comparable to other parts of the river. The saprobity indices are within the β-mesosaprobic zone, quality class III (moderate pollution). In general, the impact of wastewater during the study period is localized at the place of discharge.

Assessment of Heavy Metal Contamination in Wetlands Soils Around an Industrial Area Using Combined GIS-Based Pollution Indices and Remote Sensing Techniques

Understanding variations of heavy metals and their anthropogenic influence on wetland soils are very imperative and crucial for environmental planning and sustainability. To assess heavy metal contamination in Ibese wetland soils, Nigeria, 30 soil surface (0–20 cm) samples clustered around industrial effluents, were collected and analyzed with atomic absorption spectrophotometer for copper (Cu), zinc (Zn) and cadmium (Cd). Herein, the geo-accumulation (Igeo), and pollution index (PI), coupled with environmental (RS) remote sensing vegetation and water indices were employed as predictor models to assess heavy metals contamination of the area. The vegetation and water indices highlighted an intense decreasing vegetation trend and loss of waterbodies of the area, respectively. The results of the Igeo metals revealed that the wetland soils pollution ranged from uncontaminated to moderately contaminated, except Cd which ranged from moderately to heavy pollution. The PI shows a moderate significant pollution by Cu and Zn, except Cd which recorded considerable contamination. A very significant correlation was found between the metals and the spatial distribution pattern revealed that the contamination is related to the influence of uncontrolled human activities on soil properties like soil pH and organic carbon. The study suggested that adequate attention be directed to alert policymakers and stakeholders toward lessening the anthropogenic sources in the area for future control measures.

Classification of Rivers of Brahmaputra Basin in Assam, India Based on Designated Best Use Concept

River water quality is an important issue as rivers are one of the major sources of fresh water for drinking, agriculture, residential use, hydroelectric power plant, tourism, transportation, and others. In spite of abundance of surface water in Brahmaputra basin, only 47% rural population of Assam has access to potable water. It is important to check water quality at regular intervals and prevent and control their pollution. An attempt was made to study water quality of rivers of the Brahmaputra basin in Assam focusing designated best use concept. Water quality status was evaluated from analysis of water samples and secondary data from reports of Central Water Commission and Pollution Control Board, Assam. It is found that water of most of the rivers fall under ‘B’ and ‘C’ class (as per designated best use concept, class ‘B’ water can be used for bathing and class ‘C’ water can be used as drinking water source with conventional treatment followed by disinfection). Most of the rivers of the Brahmaputra basin have moderate or low pollution, mainly due to rejuvenated life every year during monsoon. However, with contemporary issues of population explosion, increasing demand for water, flood, growing pollution and climate change, it is imperative to take precautionary approach to the pristine as well as ecologically challenged rivers of Brahmaputra basin in India.

Environmental Impact Assessment Using Diatoms in Thamirabarani River, Tirunelveli District, Tamil Nadu, India

The present study provides a detailed report on the occurrence and record of diatom taxa from the Thamirabarani River. A total number of 55 diatom taxa belonging to 25 genera were identified. The result shows the abundance of diatom genera viz. Amphora, Aulacoseira, Cyclotella, Cymbella, Eunotia, Gomphonema, Melosira and Ulnaria in the study area indicated varying pollution levels and pristine conditions. The diversity of diatom taxa in Site 1 and Site 3-7 indicate that the river water is not polluted in these locations. Domestic waste input in the river at Site 2 area may responsible for the dominant occurrence of moderate pollution tolerant diatoms taxa. The abundance of pollution tolerant diatom taxa in Site 8, Site 9 and Site 10 areas of the river indicates high pollution. The Canonical Correspondence Analysis (CCA) results also show that the concentration of diatom taxa and physico-chemical parameters suggest the release of industrial effluents and anthropogenic activity. The proper waste water treatment methods need to be implemented along the catchment areas of the river to ratify pollution levels. Keywords: Diatoms, Thamirabarani River, Pollution, Water Quality, Anthropogenic Impact

GEOENVIRONMENTAL ASSESSMENT OF HEAVY METALS CONTAMINATION ALONG QUA IBOE TERMINAL SHORELINE, IBENO, SOUTHERN NIGERIA

Coastal sediments and soils along Qua Iboe Terminal shoreline, Ibeno have suffered high potential of being contaminated by heavy metals leading to health risk. it is expedient to evaluate their levels in terms of contamination or /and pollution on the soils and sediments. The aim of this research was to determine the extent of contamination caused by heavy metals in the study area so as to assess its eco-toxicological risk and geochemical distribution pattern. Sediment and soil samples from Qua Iboe Terminal shoreline and its environs were collected and analyzed for Six heavy metals [Copper (Cu), Lead (Pb), Molybdenum (Mo), Zinc (Zn), Chromium (Cr), and Iron (Fe)] using Inductively Coupled Plasma- Mass Spectrometry (ICP-MS). The physicochemical parameters of sediments and soils were determined using standard methods. The results of all the physicochemical parameters determined were within maximum tolerable limits. The average heavy metals concentration in soil and sediment followed the order of Zn > Cr > Pb > Cu > Mo with corresponding values for soil and sediment of 55.60, 48.30, 21.80, 11.9, 3.4 mg/kg and 47.80, 35.00, 17.90, 11.74 and 5.4 mg/kg respectively. Statistical analysis revealed that Pearson Correlation were significant at r >0.500 between some metals. The anthropogenic influence on soil indicated low contamination by Cu, Cr, and Zn and moderate contamination by Pb and Mo, for both sediments and soils. The geo-accumulation index for most metals was of class 0 (uncontaminated) except for elements like Pb and Mo. The enrichment factor had values less than 1.5 for both soil and sediments showing deficiency to minimal enrichment. The pollution load index (PLI) for sediment were < 1 indicating low pollution status and > 1 for soil at locations 4, 6, 8, 9, 13, 14 and 15 indicating moderate pollution status in some sites. Evaluated mean contamination factor revealed moderate contamination for Pb and Mo for both soil (1.71 & 3.43) and sediment(1.09 &1.14). On the basis of the analytical data available, areas in close proximity to the offshore installations (Utana/Iwokpom/Opulum Creek) have the greatest impact on sediment and soil in the study area.

Spatial distribution and ecological risk assessment of soil heavy metals in a typical volcanic area: Influence of parent materials

To understand the distribution characteristics and potential ecological risks of heavy metals in soils in the typical volcanic area, 2,592 soil samples were collected from the surface layer (0–20 cm) and 269 samples were collected from the middle (80–100 cm) and deep layers (180–200 cm) in northeast of Hainan province, China. Accordingly, eight heavy metals (Cu, Pb, Zn, Cr, Ni, Cd, As, and Hg) were analyzed and determined. The effects of different parent materials and land use types on the accumulation of heavy metals in soils were compared, and the primary heavy metal sources were analyzed. The pollution level and ecological risk of heavy metals in soils in the study area were evaluated using the geo-accumulation index (Igeo) and potential ecological risk indices (Ei &RI). The results showed that, except that of Pb, the median concentrations of the analyzed heavy metals in the surface soils were higher than the background concentrations in the Hainan Island soils, indicating varying degrees of accumulation. The influence of land use type on the accumulation of heavy metals in surface soils varied from that of the parent materials. Anthropogenic activities highly influenced As, Cd, Hg, and Pb concentrations, whereas geological conditions primarily influenced Cr, Cu, Ni, and Zn concentrations. The Igeo results showed that the mean value of the eight metal elements were greater than zero, except for Pb. In the surface soils, the Igeo values of As, Cd, Hg, and Zn mostly fell into the light to moderate pollution class, and those of Cr, Cu, and Ni fell into the medium and heavy pollution class. The RI of the study area showed a high to significantly high ecological risk because of the Cd, Hg, and Ni concentrations. The results give a new insight in the parent material's geochemical control on the heavy metal elements in soils, and it can serve as a reference for the background value of local soil heavy metals and provide a scientific basis for controlling the potential ecological risk of heavy metals and reasonable land use plans.

Distribution and Enrichments of Abundant and Trace Elements in Al-Khassa Sub Basin Soil, Kirkuk, Northeastern of Iraq

This study focused on the soil of the Al-Khassa Sub Basin, thirty-four soil samples were collected from different areas of land use and differences in human activity. Physicochemical properties of the soil were examined Hydrogen Potential (pH), Organic Matter (O.M), Loss Of Ignition (L.O.I), Total Organic Carbon (TOC), Cation Exchange Capacity (CEC) and Total Hydrocarbon (THC). Hydrogen Potential (pH) showed that the soil is alkaline above seven with a mean 7.98. Organic Matter (O.M) of the study area with a mean 1.28 % and high value found in Agricultural areas.Cation Exchange Capacity (CEC) with a mean 42.64 (cmol/kg) that is proportional to the granular size of the soil that silty clay. Both Total Organic Carbon (TOC) and Total Hydrocarbon (THC) acceptable concentration values compared to the soils of the arid region. In the present study abundant elements (Calcium (Ca), Silicon (Si), Aluminum (Al), Magnesium (Mg), Sulfur (S), Potassium (K), Chloride (Cl), Titanium (Ti) and Phosphorous (P) ) and Trace element(Chromium (Cr), Manganese (Mn), Nickel (Ni), Zinc (Zn), Vanadium(V), Copper(Cu), Lead(Pb), Arsenic (As), Cobalt (Co), Mercury (Hg) and Molybdenum (Mo)) that have been analyzed in this study and compared with the limits to elements distribution in world soil and local study of Lesser Zab. Elements that are higher than standard Ca, Cl, Cu, As,Hg, Mo, Zn because of excessive use of fertilizers and pesticides and poor irrigation practice and other anthropogenic sources. High concentration elements (Ni, Ca, Co) as a result of the weathering of the parent rocks, it occurs naturally in soils. Other elements that were partially higher than the standard is (K, Cr, P, S, Mg( only in dense agricultural areas. Elements that were lower than Standard (Ti, Al, Si, Mn, V, Pb) represent the unpolluted elements at some locations the sub-basin because they are elements that increase in urban and industrial areas that are not available in the Al-Khassa Sub Basin, main activity and land use of sub basin were rural area and cultivated land. The results of the enrichment factor (EF) and the contamination factor (CF) are calculated for contamination assessment. The Enrichment factor (EF) of the sub-basin is EF 2 depletion to minimal enrichment, indicating no or minimal pollution, but there is a real beginning of contamination of the magnesium element EF 2-5 moderate enrichment, indicating a real beginning of contamination of the magnesium element. indicating of moderate pollution due to the presence of farms that were use of magnesium sulfate fertilizers by villagers at sedan. The results of the Contamination Factor (CF) showed that the region is low to moderate contamination Except for the contamination factor of magnesium in Mam Rash (S22), Belgrad (S10) was very high degree of contamination of Cf > 6, and in Sedan (S25), Gurgay Shammar (S11), and Obarick (S32) was considerable degree of contamination of magnesium 3 < Cf < 6 because of the three villages was agricultural area that use of magnesium fertilizer. Phosphor (P) contamination factor is moderate in Heon (S7), Ali Makaeel (S20) because they are villages that use phosphate fertilizers beside occurrence of poultry farms.

Characterization of Spatiotemporal Variations in Mert Stream Water Quality by Phytoplankton Community and Biological Indices

In order to determine the water quality of the Mert Stream, algal indicators and some biological indices (TDI, IDG, PTI, Palmer, DAIpo) based on phytoplankton species were used. Phytoplankton samples were performed monthly from six different sites at a depth of 0.5 meter using a one-litre water sampler between July 2011 and June 2012. After phytoplankton samples were placed in 250-mL dark bottles and fixed with Lugol’s solution until processed in the laboratory, they were identified and counted in the tubular plankton counting chambers using an inverted microscope according to Utermöhl method. Bacillariophyta members became the dominant division in the phytoplankton with an abundance rate of 83.3% and 71 taxa. Lindavia glomerata, Navicula cryptocephala, Cyclotella planctonica, and Navicula veneta were determined as the most dominant species among phytoplanktonic taxa of Mert Stream. Trophic diatom index (TDI) and Generic diatom index (IDG) based on planktonic diatoms were used to determine the trophic status of the Mert Stream. Pollution tolerance index (PTI), Diatom assemblage index (DAIPo) and Palmer index were also included to assess the organic load-based sabrobity level of the Mert Stream. According to the results of mean TDI and IDG (55 and 13, respectively), the trophic status of the Mert Stream is a mesotrophic structure with moderate nutrients and good water transparency. According to the average PTI result (2.7), Mert Stream is in the β-mesosaprobic class, which corresponds to moderate pollution. Considering DAIpo indice, the saprobity of Mert stream is α-oligosaprobic level and the stream is not exposed to a serious organic-based pollution. However, according to the Palmer index, all stations of the Mert Stream except the 6th station are under the threat of high organic pollution. In present study, it was seen that the best biological index that reflects the station-based trophic structure of the stream is IDG, and the best biological index that reflects the station-based organic pollution of the stream is PTI.

Pollution Levels and Potential Health Risks of Potentially Toxic Elements in Indoor and Outdoor Dust during the COVID-19 Era in Gómez Palacios City, Mexico

The COVID-19 pandemic has caused a decrease in outdoor activities, but an increase in indoor ones. This change in the intensity of land use has caused changes in pollution patterns. Urban dust contaminated with heavy metals can be a risk to the human population. Therefore, the objective of this work was to evaluate the pollution caused by heavy metals in urban dust indoors and outdoors due to changes in land use during the pandemic. Sampling was carried out by the Gomez Palacio citizens. The total number of urban dust samples was 330, 50% indoor samples and 50% outdoor sample. The elements studied were Ca, Cu, Fe, K, Mn, Ni, Pb, Rb, Sr, Ti, Y, Zn, and Zr. The heavy metals were measured through a portable XRF; the contamination factor and the load pollution index were used to assess the pollution level. The human health risk was evaluated with the USEPA methodology. Cu, Pb, and Zn presented higher concentrations indoors than outdoors, probably due to domestic factors, such as the age of the houses and the paint on the walls. Zn presented the highest pollution level among all the metals, outdoors and indoors; spatially, the sites sampled in the northwest, close to agricultural areas, presented the highest Zn pollution. Pb had a moderate pollution level in most of the samples (60%), but some samples showed a high Pb pollution. The health risk was considered within the acceptable levels for Cu, Fe, Ni, Pb, Zn. However, Mn deserves attention because the average of the samples slightly exceeded the USEPA safety limits for children. Children are at higher risk compared to adults. Indoor environments need to be better analyzed because they were shown to represent a higher risk to the population than outdoor ones due to heavy metal pollution by Zn, Cu, and Pb. The pandemic impacted land use intensity; this study reports an apparent effect of the pandemic on the amount and type of heavy metals indoors and outdoors.

A baseline study of polycyclic aromatic hydrocarbons distribution, source and ecological risk in Zhanjiang mangrove wetlands, South China

Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants and pose a severe threat to human health. Here, 38 surface sediment samples collected from the Gaoqiao mangrove wetland in Zhanjiang, south China, were analyzed to determine 16 Environmental Protection Agency (EPA) priority PAHs. Total PAHs concentrations ranged from 33.5 µg/kg to 404.8 µg/kg with an average of 147.7 ± 77.7 µg/kg, inferring a moderate pollution level. Three and four-ring compounds dominated the PAHs composition patterns. Significant positive correlations were observed between the PAHs and the physicochemical properties of the sediments. According to the characteristic molecular ratio method, PAHs in sediments were mainly derived from combustion sources, including the incomplete combustion of liquid fossil fuels, grass, wood, and coal. The result based on the PMF model indicates that the primary combustion sources of PAHs are coal combustion, diesel-powered vehicles, biomass combustion and gasoline-powered vehicles, with a share of 39.01%, 25.21%, 12.72% and 10.48%, respectively. The petrogenic source contributes 12.58% PAHs to the sediments. The mean effects range median quotient (m-ERM-Q) and toxic equivalent method (TEQ) indicate a low comprehensive ecological risk of PAHs in the study area. Still, the evaluation results of effects range low (ERL) suggest that PAHs in the sediment would occasionally have adverse biological effects. Therefore, this situation demands attention and calls for protection strategies in the processes of urbanization and industrialization in south China.