Contamination Classes Research Articles

Rapid and accurate classification of Aspergillus ochraceous contamination in Robusta green coffee bean through near-infrared spectral analysis using machine learning

Near-infrared (NIR) spectral-based classification of Aspergillus ochraceous contamination in the Robusta green coffee bean was investigated. Six different learning algorithms, including linear discriminant analysis (LDA), support vector machine (SVM), k-nearest neighbors (KNN), decision tree (Tree), Naive Bayes (NB), and quadratic discriminant analysis (QDA), were applied for the investigating purpose. Four classes of fungal contamination on coffee beans, non-fungal contaminated beans on day 1 and day 3 (NCB-D1 and NCB-D3) and fungal contaminated beans on day 1 and day 3 (CB-D1 and CB-D3), were set for the classification intention. Based on the 6 learning algorithms, the Tree approach was optimal, displaying a training accuracy of 97.5%. As proven by the testing dataset, the classification accuracy of the Tree was also at 97.5%. With this number, the Tree could correctly classify 100% between the contaminated and non-contaminated coffee beans. These findings exhibit the potential of the NIR spectroscopy accompanied by machine learning for the early detection of fungal contamination in green coffee beans.

Predicting the Class of Salt Contamination for Wind Turbine Blade under a Lightning Strike Using Fuzzy Inference System and Probabilistic Neural Network

This study predicts the class of salt contamination for wind turbine blades that undergo a lightning strike using a fuzzy inference system (FIS) and a probabilistic neural network (PNN). The experiment uses four classes of equivalent salt deposit density to determine the salt contamination status for a wind turbine blade. The greatest degree of salt contamination is 338.9 µg/cm2. The rotational speeds of the blades are set as 0, 50, 100, and 150 rpm. Many lightning strike surge experiments are conducted for different types of salt-contaminated blades. The lightning current signals in the grounding line are measured using a high-frequency current transformer. This study uses an experimental method to determine the effect of salt contamination on wind turbine blades during lightning strikes. In terms of prediction, FIS and PNN are used to predict the four classes of salt contamination. The peak absolute value and the average power of the measured signals are the input datasets for the FIS and the PNN. The predictions for the ESDD classes are 94.8% for a FIS and 88.8% accurate for a PNN. The research results show that the proposed method accurately predicts the salt contamination class for wind turbine blades.

Geospatial analysis of groundwater contamination by heavy oil in the Dammam aquifer-Middle of Iraq

This study aims to apply Artificial Neural Network (ANN) to map the groundwater contamination of the Dammam aquifer by heavy oil in the middle of Iraq. For this purpose, the inventory map of 139 groundwater wells (contaminated and non-contaminated with heavy oil) with the seven important factors playing a role in controlling contamination were used. The factors are distance to faults, faults density, groundwater depth, aquifer saturated thickness and hydraulic conductivity, elevation, and distance from Abu Jir fault. For the performance of ANN model, five statistical measures were used namely, accuracy, sensitivity, specificity, kappa, and the relative operating characteristic curve. Obtained results from applying the model in R statistical package indicated that ANN has a high accuracy (> 90%) in training and testing phases. The probability prediction of ANN model was categorized into five groundwater contamination classes: very low-low, moderate, high-very high. The averages of areas occupied by these zones were 5267 km2 (65%), 488 km2 (6%), and 2362 km2 (29%), for very low-low, moderate, and high-very high, respectively. The contamination map developed in this study could be used to drill successful non-contaminated groundwater wells and avoid loss of many efforts in drilling contaminated wells in the study area.

Evaluation of environmental contamination by toxic trace elements in Kazakhstan based on reviews of available scientific data.

The environmental situation concerning pollution by (eco)toxic and persistent trace elements in Kazakhstan has been investigated by analytical reviews of scientific studies published over the past 20 years reporting concentrations of 10 toxic trace elements (TTE) observed in soil, sediments, or surface water. A database of 62 articles published in Kazakh, Russian, or English covered the majority of the territory of the country for soil and water samples but to a lesser extent for sediments. Reported concentrations were summarized using statistical parameters, then spatialized and finally classified in contamination classes according to local legislation. This analysis revealed some hotspots of TTE in surface waters (Cd and Pb), soil (As), and sediments (Cd and As). Hotspots of less toxic Cu, Zn, and Mn were also detected. Spatialization of results allowed localization of these hotspots close to industrial sites, such as smelters or mining and metallurgic combines. Others have been shown to be close to disused mining sites or landfills with municipal waste. Methodological improvements for further studies have been suggested, such as to integrate more West Kazakhstan or remote areas in sampling campaigns, but also to describe more exhaustively the used analytical methods and to be more attentive to the speciation of the analyzed form of the element. Finally, a management strategy to strengthen a sustainable food policy has been proposed: to reduce emissions by modernization of industrial facilities and better waste management, to organize land use depending on the contamination levels, and to reduce the bioavailability of the toxic elements.

Prophylaxis of infection in region of the surgical intervention performance in laparoscopic cholecystectomy

Objective. To estimate the efficacy of prophylactic method for regional infection while performance of laparoscopic cholecystectomy, using simultaneous application of container for removal of the specimen and a two-ring wound protector of the wound. In accordance to the literature data, the infection rate in laparoscopic cholecystectomy conduction constitutes 2.4 - 9.6%.
 Materials and methods. The work was based on experience of performance of 759 laparoscopic cholecystectomies during the period of 2015 - 2018 yrs. There were performed 679 operations with the second class of microbial contamination, 17 - with the third one and 6 - with the fourth. In 21 patients the conversion into laparotomy was applied. The patients with third and fourth classes of microbial contamination of wounds were divided into two groups: the first - 61 patients, in whom a container was used for the specimen removal, and the second - 19 patients, in whom the method of combined application of container and the wound protector was applied for removal of the specimen.
 Results. Infection of region of the surgical intervention performance in laparoscopic cholecystectomy was revealed in 41 (5.40%) of 759 patients.In surgical interventions In surgical interventions, referring to second class of microbial contamination , the infection rate in the surgical intervention region have constituted 2,5%, while referring to the third class - 11.76%, and the fourth class - 34.92%. Conversion in laparoscopic cholecystectomy is accompanied with high rate of the wound infection - 38.09%.
 Conclusion. Application of the method of combined usage of container for removal of preparation and a two-ring protector of the wound in the third and the fourth classes of the wounds while performance of laparoscopic cholecystectomy have permitted to lower the infection rate in region of the surgical intervention performance from 37.70 to 5.26%.

Passive air sampling: the use of the index of microbial air contamination.

Background:Bioaerosol plays an important role in human life with potentially infectious, allergic and toxic effects. Active and passive methods can be used to assess microbial air contamination, but so far there is not a unanimous consensus regarding the indications about methods to be used and how to interpret the results. The passive method has been standardized by the Index of Microbial Air contamination (IMA). Classes of contamination and maximum acceptable levels of IMA have been proposed, related to different infection or contamination risks. The aim of this study was to provide information about the use of the passive sampling method, with reference to the IMA standard.Methods:We searched PubMed and Scopus for articles published until January 2020 reporting the citation of the article by Pasquarella et al. “The index of microbial air contamination. J Hosp Infect 2000”. Only studies in English language where the IMA standard was applied were considered. Studies regarding healthcare settings were excluded.Results:27 studies were analyzed; 12 were performed in Europe, 8 in Asia, 5 in Africa, 2 in America. Cultural heritage sites, educational buildings and food industries were the most common indoor monitored environments; in 8 studies outdoor air was monitored.Conclusions:This review has provided a picture of the application of standard IMA in different geographic areas and different environments at risk of airborne infection/contamination. The analysis of the results obtained, together with a wider collection of data, will provide a useful contribution towards the definition of reference limits for the various types of environments to implement targeted preventive measures.

Soil Nematodes as Indicators of Heavy Metal Pollution: A Meta-Analysis

Nematodes have been used as bioindicators of soil quality for more than 20 years, and have been shown to have good potential for assessing the impact of heavy metal pollution on soil. They provide information about the biological condition of soil and can reveal dysfunctions linked to the presence of contaminants. In the case of contamination by multiple pollutants, bioindicators can reveal synergistic toxic effects (or “cocktail effects”) on organisms living in soil. These impacts are not revealed by the individual measurement of each pollutant. As the effects of heavy metals on nematode communities are not fully known, identifying reliable nematode-based parameters is not straightforward. Currently, knowledge gaps limit the operational use of these types of indices by soil managers. In this study, we performed a meta-analysis on the results of 37 studies from different countries to reveal general trends regarding the effect of multiple types of heavy metal pollution on soil nematode communities and indices. Based on the contamination level of each metal and using known toxicological threshold values, we defined four contamination classes to categorize soil polluted by heavy metals: normal concentration (c0), low contamination (c1), high contamination (c2), and very high (c3) contamination. The most sensitive nematode parameters, showing a strong relationship with the level of soil pollution, were the structure footprint, community footprint, abundance per trophic group (plant feeders, bacterial feeders and omnivores/predators) and taxonomic richness: all these parameters decreased with increased contamination. Our findings showed that fungal-feeding nematodes were relatively insensitive to metal contamination of soil and actually had a higher abundance in the very high contamination class (c3).

Geobiological assessment of the pollution effect of abandoned mine ores (Fej Lahdoum, Northwest Tunisia)

The present work deals with a geobiological assessment of metal pollution in the abandoned Fej Lahdoum mine in Northwest Tunisia. The geological part of the assessment deals with the petrographic, mineralogical, and geochemical study of wastes, soils, and water collected from the mine. The biological part of the assessment investigated the metal presence within leaves and roots of Ampelodesmos mauritanicus and Typhonium flagelliforme species. Waste characterization revealed the presence of potentially toxic elements (PTEs) mainly Pb and Zn (46,040 and 17,650 mg kg−1, respectively, as average value). Anomalous contents in metals exceeding the geochemical background and global range specified for calcic soils are found with average concentrations up to 10,313 mg kg−1 for Pb and 5282 mg kg−1 for Zn, maximum levels are detected in soils in the immediate vicinity of the dumps particularly in the upper horizons but also in depth resulting from plowing and mud cracks which facilitated the incorporation and vertical migration of the pollutants. Enrichment factor (EF) and geoacumulation index (Igeo) indicated different classes of contamination of Fej Lahdoum soils. Metal concentration in plants and water is not very high compared to soils and does not exceed the maximum recommended concentrations, thus, not currently presenting a risk of contamination of the food chain. Nonetheless, further erosion and leaching would have relevant damage on water and plants.

Виробнича перевірка ефективності вакцини «Мастивак» проти клінічних та субклінічних маститів

При проведенні клінічних випробувань вакцини «Мастивак», корови були розділені на дві групи за принципом аналогів по 10 голів у кожній. Вакцину вводили підшкірно в ділянці середньої ділянки шиї в дозі 5 см3. Корови першої групи вакциновані двократно з інтервалом 15 днів. Корови другої групи вакцинації не піддавались. За коровами вели щоденне клінічне спостереження та щотижневе дослідження зразків молока. У корів другої групи (не вакцинована) були виявлені дві тварини з клінічними ознаками маститу та чотири тварини з ознаками субклінічного маститу. При дослідженні молока корів виявили, що у корів другої групи знижені показники якості молока – клас забрудненості молока 1, 2 та 3 в той час як молоко корів першої групи відповідає вищому класу.

Assessment of heavy metals concentrations in the soil of Mongla industrial area, Bangladesh

Background: Contamination of soil with heavy metals is an alarming issue around the world. Therefore, this study aimed to assess the contamination status of heavy metals in the soil of Mongla industrial area, Bangladesh. Methods: Soil samples were randomly collected from 20 sites and digested by wet digestion method. The concentrations of heavy metals (Mn, Fe, Cu, Zn, Cd, and Pb) were determined using atomic absorption spectrophotometer (AAS). The quality of soil was assessed based on the contamination factor (CF), geoaccumulation index (Igeo), enrichment factor (EF), and ecological risk index factor (ERIF) analyses. Results: The average concentrations of Mn, Fe, Cu, Zn, Cd, and Pb were obtained to be 258.08±51.61, 3736.90±322.17, 19.55±6.49, 66.76 ± 18.32, 0.59±0.13, and 10.40 ± 1.49 mg kg-1, respectively, which were below the permissible limit. The highest value of CF (0.74±0.16), Igeo (0.35±0.34), EF (24.86±6.27), and PERIF (22.11±4.81) was observed for Cd. The pollution of CF, Igeo, EF, and ERIF was classified as very severely polluted, unpolluted to moderately polluted, strongly to extremely polluted, and slightly polluted, respectively, with these heavy metals due to anthropogenic activities. One-way ANOVA indicated a significant difference between Zn and Cd concentrations (P<0.05), whereas Pearson correlation showed a positive correlation between Zn-Pb (P=0.01) and Fe-Zn (P=0.05). Conclusion: There are different classes of contamination with heavy metals in the study area. Therefore, necessary steps should be taken and people’s awareness of the soil pollution should be raised.

Lability of toxic elements in Submarine Tailings Disposal: The relationship between metal fractionation and metal uptake by sandworms (Alitta virens)

Mine tailings from the iron ore mine Sydvaranger Gruve have been deposited in Bøkfjorden, Northern Norway, for >40 years. This study investigates the environmental impacts of submarine tailings disposal one year after the cessation of the mine by combining analyses of total metal concentrations (nitric acid digestion) and metal fractionation patterns (sequential extraction procedure) of sediments with the metal uptake (bioassays) by sandworms (Alitta virens) exposed to Bøkfjorden sediment. The analyses focused on metals (As, Cd, Cr, Cu, Fe, Ni, Pb, Zn) in sediment cores retrieved from a horizontal transect of the fjord. High concentrations of the target metal iron was found in the fjord (>13,000 mg/kg). According to Norwegian sediment quality guidelines (SQG), cadmium (2.55 mg/kg) and lead (174 mg/kg) were the only metals to exceed good sediment quality at the source area of mine tailings discharge. Despite general low total metal concentrations, labile (summarized exchangeable, acid soluble, reducible fractions) and potentially labile (summarized labile and oxidisable fractions) pools of mine tailings-related metals of cadmium (10–82%), copper (25–88%) and lead (10–67%) were detected while iron were characterized as inert (residual fraction: 89–97%). Despite spatial trends in total metal concentrations presumed to originate from mine tailings (Cd, Cu, Fe, Pb), there were no correlations between total and labile fractions. This can be explained by the high concentrations of iron, which under oxidised forms are suggested to inhibit a high lability of other metals. The metal uptake of sandworms was generally high compared to similar studies and exceeded moderate contamination classes for all metals compared to Norwegian standard values. Both labile metal fractions (cadmium, copper and iron) and total metal concentrations (copper, iron) showed positive correlations (r > 0.6) with metal uptake. Thus, both the total and labile metal fractions can pose an environmental risk.

Determination and Contamination Assessment of Heavy Metals in Street Dust from Different Types of Land-Use in Kathmandu District, Nepal

A total of forty seven street dust samples, collected from five different types of land use viz., industrial, urban, heavy traffic road, residential and undisturbed areas (control) of Kathmandu district (Nepal), were subjected to characterize the physico-chemical parameters such as pH, electrical conductance (EC), total alkalinity (T. Alk), total organic carbon (TOC) and particle size distribution. Four heavy metals of Cd, Cu, Pb and Zn were determined in dust samples using flame atomic absorption spectrophotometer (FAAS). It was found that all types of dust samples possessed alkaline nature along with variation in EC, T. Alk and TOC values. Results revealed that the dust of industrial areas contained high concentrations of Zn (143.3 mg/kg) and Cu (106.42 mg/kg), whereas the heavy traffic areas were mainly affected by Cd (0.90 mg/kg) and Pb (70.08 mg/kg). The average metal concentrations of Cd, Cu, Pb and Zn in dust of all the types of land use in Kathmandu were found to be 0.73, 68.86, 51.46 and 104.30 mg/kg and their average metal enrichment factors were 2.28, 5.50, 1.92 and 3.17, respectively. The results were also compared against heavy metals status in street dust from various cities/countries around the world. Pollution indices such as contamination factor (CF), degree of contamination (CD) and geo-accumulation index (Igeo) showed different classes of metal contamination in street dust of Kathmandu indicating traffic emission, automobiles, construction and demolition activities and other anthropogenic activities as the potential sources.

REsiDENT 1 (Re-assessment of Appendicitis Evaluation during laparoscopic appendectomy: Do we End a Non-standardized Treatment approach and habit?): peritoneal irrigation during laparoscopic appendectomy\u2014does the grade of contamination matter? A prospective multicenter resident-based evaluation of a new classification system

BackgroundLaparoscopic appendectomy has progressively gained acceptance as the standard of care for acute appendicitis. Focusing on the incidence of postoperative intra-abdominal abscess after a laparoscopic appendectomy, discordant data have been reported ranging from 1.5 to 20%. Besides, evidence advocating advantages from peritoneal irrigation over suction only are lacking. Most studies are burdened by a high level of heterogeneity regarding the severity of the appendicitis and modalities of peritoneal irrigation. One of the main drawbacks is the lack of an accepted classification for different degrees of appendicitis and peritoneal contamination. The aim of the study is to introduce a classification to clarify the relationship between grade of appendicitis, contamination, and postoperative incidence of IAA considering the surgeon’s attitude toward irrigation or suction alone. Preoperative, intra-operative, and postoperative predictive factors for infectious complication will also be assessed. This study is meant to be the first Italian multicenter resident-based observational study.MethodsPatients suffering from acute appendicitis will be enrolled during a 1-year period, according to inclusion and exclusion criteria. Participants will fill an online form reporting all clinical and intra-operative data of each patient undergoing a laparoscopic appendectomy. General surgery residents will be responsible for data collection. Our proposal of classification is based on the histological grade of appendicitis and intra-operative degree of peritoneal contamination. For each grade, a progressively increasing score is assigned.DiscussionThe observational nature of this study is mandatory to examine surgeons’ attitude toward peritoneal contamination during laparoscopic appendectomy for appendicitis. Identification of different severity grades of acute appendicitis and their relationship with the development of postoperative abscesses is necessary. The resulting classification and score, even considering peritoneal lavage or suction alone, will define risk classes of peri-appendiceal contamination each one related to a specific incidence rate of postoperative IAA. Nowadays, maximum effort should be made to reach the best procedural standardization and surgical decision-making should be supported by solid evidence, especially in an emergency surgery setting.

Combining E-Nose and Lateral Flow Immunoassays (LFIAs) for Rapid Occurrence/Co-Occurrence Aflatoxin and Fumonisin Detection in Maize.

The aim of this study was to evaluate the potential use of an e-nose in combination with lateral flow immunoassays for rapid aflatoxin and fumonisin occurrence/co-occurrence detection in maize samples. For this purpose, 161 samples of corn have been used. Below the regulatory limits, single-contaminated, and co-contaminated samples were classified according to the detection ranges established for commercial lateral flow immunoassays (LFIAs) for mycotoxin determination. Correspondence between methods was evaluated by discriminant function analysis (DFA) procedures using IBM SPSS Statistics 22. Stepwise variable selection was done to select the e-nose sensors for classifying samples by DFA. The overall leave-out-one cross-validated percentage of samples correctly classified by the eight-variate DFA model for aflatoxin was 81%. The overall leave-out-one cross-validated percentage of samples correctly classified by the seven-variate DFA model for fumonisin was 85%. The overall leave-out-one cross-validated percentage of samples correctly classified by the nine-variate DFA model for the three classes of contamination (below the regulatory limits, single-contaminated, co-contaminated) was 65%. Therefore, even though an exhaustive evaluation will require a larger dataset to perform a validation procedure, an electronic nose (e-nose) seems to be a promising rapid/screening method to detect contamination by aflatoxin, fumonisin, or both in maize kernel stocks.

Potential effects of groundwater and surface water contamination in an urban area, Qus City, Upper Egypt

The potential effects of anthropogenic activities, in particular, unsafe sewage disposal practices, on shallow groundwater in an unconfined aquifer and on surface water were evaluated within an urban area by the use of hydrogeological, hydrochemical, and bacteriological analyses. Physicochemical and bacteriological data was obtained from forty-five sampling points based on33 groundwater samples from variable depths and 12 surface water samples. The pollution sources are related to raw sewage and wastewater discharges, agricultural runoff, and wastewater from the nearby Paper Factory. Out of the 33 groundwater samples studied, 17 had significant concentrations of NO3−, Cl− and SO42−, and high bacteria counts. Most of the water samples from the wells contained high Fe, Mn, Pb, Zn, Cd, and Cr. The majority of surface water samples presented high NO3− concentrations and high bacteria counts. A scatter plot of HCO3− versus Ca indicates that 58% of the surface water samples fall within the extreme contamination zone, while the others are within the mixing zone; whereas 94% of groundwater samples showed evidence of mixing between groundwater and wastewater. The bacteriological assessment showed that all measured surface and groundwater samples contained Escherichia coli and total coliform bacteria. A risk map delineated four classes of contamination, namely, those sampling points with high (39.3%), moderate (36.3%), low (13.3%), and very low (11.1%) levels of contamination. Most of the highest pollution points were in the middle part of the urban area, which suffers from unmanaged sewage and industrial effluents. Overall, the results demonstrate that surface and groundwater in Qus City are at high risk of contamination by wastewater since the water table is shallow and there is a lack of a formal sanitation network infrastructure. The product risk map is a useful tool for prioritizing zones that require immediate mitigation and monitoring.

Environmental evaluation of geochemical changes in bottom sediments of Ustia headwater

Any changes to anthropogenic impact within the watersheds involving the transformation of ecosystem relationships cause irreversible changes in the structure and composition of sediments. The objective of the research was to analytically compare the results of the study on heavy metals in Ustia River sediments with the use of various methods for determining environmental geochemical changes in headwaters due to human transformation of the basin between 1994 and 2015. Ustia River experienced the highest anthropogenic impact during 1968–1994. Starting from 1968 and up to the present time the wastewater volume disposed to the river is more than 25 m3 per day. Despite the downturn in the national economy since the mid 90-ies of the 20th century, the negative impact on the environment of surface water area does not stop. The environmental evaluation of the bottom sediments of Ustia River was held basing on the results of spectral analysis of air-dried samples of silt fraction from the selected samples. The researcher analysed the content of heavy metals which emission takes place within the river basin as a result of runoff generated by chemical and woodworking industries, transport, wastewater and agricultural use of the territory, particularly Pb, Mn, Co, Cu, Zn and Cd. For the first time, researchers have figured out that for the past twenty years there has been no improvement in the overall ecological state of the Ustia River bottom sediments. The human impacts on the hydro-ecosystem, assessed according to the content of heavy metals, have moderated only in the river section near the headstream. The author views this fact as a consequence of reduced chemicals’ usage (i.e. fertilizers, pesticides, compost, sewage and animal waste) on the cultivated land in this part of the basin. The remaining sections of riverbed have experienced deterioration of the bottom sediments; it is particularly notable with regard to the content of such elements as Mn, Cu, Zn and Pb within the urban areas. The increase of the concentrations of metals in the sediments near Basiv Kut Dam Lake in 2015, compared with the relevant data for 1994, can serve as the evidence that the negative impact on hydro-ecosystem has intensified. In both observation periods the bottom sediments of the upper part of the river has demonstrated extremely high content of Mn. Hence, in 1994 it markedly declined in the central section of the stream, and in 2015 it appeared in significant concentrations in the sediments along the channel. It is obvious that in this case there are geochemical features of the basin; however the situation in 2015 indicates a change in the state of bottom sediments with regard to the content of Mn under the influence of anthropogenic factors. The analysis of the geochemical changes in bottom sediments of Ustia headwater from 1994 until 2015 show that the concentrations of such elements as Cu, Zn, Pb, Co and Cd in the bottom sediments according to 2015 data turned out to be higher compared to 1994, excluding the upper part of the river. Nevertheless the geochemical anomalies of Mn contents noticed along the channel are also the case in this situation. The level of anthropogenic impact, measured in terms of total pollution index for the concentration of heavy metals in bottom sediments in both observation periods appeared to be «weak» or «slightly increased» if there were toxic elements. Hence, if in 1994 there was a high risk of pollution of bottom sediments with such elements as zinc, lead and copper both in case of the relative background values and hygiene criteria (maximum allowable concentrations in soil), in 2015 cobalt also appeared among such elements. The level of contamination of sediments according to international contamination classes mainly shows «significant» and «increased» impact on different parts of the river for the Mn content (5–6 grades) in both observation periods; the Cu and Zn content vary from «low» to «moderate» in 1994 (1–3 grades) and from «low» to «substantial» in 2015 (2–4 grades); the Pb content is «poor» (grade 1) in 1994 and «moderate» in 2015; Co and Cd content describes human impact on hydro-ecosystem as «weak» in both periods (0–1 grades). The assessment methods used by the researcher allowed tracking various aspects of heavy metal pollution in the bottom sediments. Furthermore, they help discovering that nowadays the sediments of Ustia River play the role of anthropogeny outcome battery against the geochemical anomalies of individual elements.

Assessment and mobility of heavy metals in carbonated soils contaminated by old mine tailings in North Tunisia

The activity of the former Pb–Zn mine of Jebel Ghozlane, located in the extreme north of Tunisia, generated during the last century large quantities of tailings (extraction, flotation, gravimetry), which are deposited without concern for environmental issues. The tailings contain both primary (galena, sphalerite, pyrite) and secondary (cerussite, smithsonite, iron oxi-hydroxides) heavy metals bearing minerals. The gangue minerals are composed of calcite, dolomite, barite, celestite and quartz. The concentrations of Pb, Zn and Cd in the tailings vary from 1.2% to 5.7%, 9.3% to 13.6%, and 185.6 to 410.6mgkg−1, respectively. The soils surrounding the tailings piles, developed on a calcareous bedrock, are characterized by alkaline pH (H2O) ranging from 6.8 to 7.9. In addition, cation-exchange capacity (CEC) was low with a mean value of 4.25cmolkg−1 and organic matter (OM) content varied between 2.23% and 6.13%. These soils contain high amounts of Pb, Zn and Cd, that can reach 3052mgkg−1, 22,086mgkg−1 and 99.3mgkg−1, respectively. The contamination levels by heavy metals (HM) in the soils were evaluated using the modified degree of contamination (mCd). This evaluation shows that 60% of the analyzed soils are between the high degree and the ultra-high degree of contamination classes. The extraction tests using deionised water, salt (CaCl2), low-molecular-weight organic acids (LMWOAs) and chelating agent (DTPA) solutions were performed to evaluate the mobility of Pb, Zn and Cd in soil samples. Results show that, the extractability of heavy metals is slightly influenced by pH, CEC and total carbonate (TC) content of the soil. The amounts extracted with water and CaCl2 are negligible. The highest percentages of total heavy metals are extracted with DTPA (0.7–19.5% for Pb, 0.3–6.2% for Zn and 0.4–11.9% for Cd) and at a lesser degree by LMWOAs (0.1–0.8% for Pb, 0.1–2.5% for Zn and 0.1–1.9% for Cd). These results showed that the mobility of metals is generally very low and influenced by the high carbonate content of soils.

A New Assessment of Heavy Metal Contaminations in an Eutrophicated Bay (Inner Izmir Bay, Turkey)

The distribution, controlling geochemical factors and contamination status of heavy metals in inner Izmir Bay (Eastern part of Aegean Sea) were investigated. 23 surface sediment samples were collected and analized for major elements (Al and Fe), heavy metals (Pb, Zn, Cd, Cu, Hg, Cr, Mn), organic matter, grain size composition, carbonate and Chl.-a. Metals controlling factors were elucidated based on statistical methods such as the Pearson product-moment linear correlation and Factor Analysis. The results illustrated that Pb, Zn, Cr and Cd are mainly controlled by organic matter and a lesser extent Fe. Pb also controlled by carbonate and Mn additionally. Other controlling factor on Cr and Cd are Chl.-a via uptake in water column and then sedimentation. Cu and Hg are mainly controlled by Chl.-a. Some evidences were found on changing of carrier phases. The results indicated that contamination of surface sediments in inner Izmir Bay is dominated Pb, Hg, Cd, Zn and to a lesser extent Mn, Cu, Cr and Fe. Igeo classification was consistent with the Enrichment Factor ans Contamination Factor classes generally. Geoaccumulation index values for Zn, Hg, Cr and Cd have decreased two contamination classes from 1994 to 2008, whereas Pb has remained the same and Cu has decreased only one class. Generally Cu, Zn, Pb, Hg and Cr contaminations were below effects range median values. The extent of heavy metal contamination and degree have been affected significantly by sedimentological parameters such as grain size, organic carbon, carbonate and chloropyll-a.

Anthropogenic Influence on Selected Heavy Metal Contamination of Urban Soils of Akure City, Nigeria

Levels of Cd, Ni, and Pb in topsoil (0–5 cm) taken from seven different sites of the urban city of Akure, Nigeria, were determined using flame atomic absorption spectrophotometer after the wet digestion method. This was with a view to appraising the influence of various anthropogenic activities on heavy metal contamination of the urban soil. Results show that the range of Cd was 6.27–10.34 ppm, Ni 7.17–14.78 ppm, and Pb 9.22- 46.19 ppm. This analytical data indicated a significant accumulation of heavy metals above background levels, with highest concentrations found in mechanic/battery charger workshops. The level of accumulation was assessed using accumulation factor (AF), and the values obtained exceeded 4 in all sites. This implies that the heavy metals are not from the natural geochemistry of Akure but from human activities. The classes of contamination were differentiated using geoaccumulation index (I geo). The I geo performed revealed that Cd (2< I geo<3: Class 3), Ni (2< I geo<4: Class 3 and 4) and Pb (3< I geo<5: Class 4 and 5) belong to different classes of geoaccumulation index, but the contamination patterns (moderately to strongly contaminated) are similar in all sites, except the mechanic battery/charger workshop (moderately to extremely contaminated). The differences observed in the metal concentrations among the sites are statistically significant (P < 0.05).

Calculating Pollution Indices by Heavy Metals in Ecological Geochemistry Assessment and a Case Study in Parks of Beijing

Pollution index is a powerful tool for ecological geochemistry assessment. The commonly used pollution indices by heavy metals in soils and sediments were classified as two types of single index and integrated index in an algorithm point of view. Four single indices of contamination factor (or concentration factor), ecological risk factor, enrichment factor, and index of geo-accumulation were illustrated, and the reference values for calculating single indices were distinguished into background levels and threshold pollution values. Eight integrated indices were divided into two groups. One group is suitable for the normal distribution single indices including the sum, average, weighted average, vector modulus, and Nemerow pollution indices, and the other for log-normal distribution including the product, root of product, and weighted power product pollution indices. Using background levels as reference values, five contamination classes were divided, and the terminologies are suggested for the single and integrated indices to unify the assessment results. Software of EGAPI was developed in a single document interface to calculate the four single and eight integrated indices by heavy metals to assess the quality of soil and sediment ecological geochemistry. Pollution indices by heavy metals of Cu, Pb, and Zn in soils in parks of Beijing were calculated using EGAPI software, and these five contamination classes and terminologies suggested in this study were evaluated and used. Results of integrated indices of Cu, Pb, and Zn in soils indicated that the soil qualities are unpolluted as a whole and varied from low polluted to unpolluted status from the center to the outskirts of Beijing City.