Identification of factors controlling heavy metals/metalloid distribution in agricultural soils using multi-source data.

Understanding the factors that controlling the agricultural soil heavy metals/metalloids distribution is vital for cropland soil remediation and management. For this objective, 227 agricultural soils were sampled in the Guanzhong Plain, China, to measure the concentration of five heavy metals (Pb, Cd, Ni, Zn, and Cu) and one metalloid (As) by X-ray fluorescence spectrometer, meanwhile, 24 possible influencing factors to agricultural soil heavy metals/metalloid distribution were collected and grouped into three categories. A sequential multivariate statistical analysis was carried out to provide insight into the controlling factors of soil heavy metals/metalloid distribution, then stepwise multiple linear regression (SMLR) and partial least squares regression (PLS) were used to predict heavy metals/metalloid concentrations in agricultural soil based on the result of soil heavy metals/metalloid controlling factors identification. The results demonstrated the types of soil and land use did not have a substantial effect on soil heavy metals/metalloid distribution, except Zn and Cu. The soil properties category played a major role in influencing the soil heavy metals/metalloid concentration. The concentrations of Mn and Fe, which are the main constitute elements of soil inorganic colloid, were the most significant factors, followed by the concentrations of P, K and Ca. Soil pH and soil organic matter (SOM) content, which are often considered as important factors for soil heavy metals/metalloid distribution, were not important in the present study. The SMLR was more effective than the PLS for predicting soil heavy metals/metalloid content. The results of this study enlighten that future soil heavy metals/metalloid contamination treatment in regions with high pH and low SOM content should concentrate on inorganic colloid particles, which have strong adsorption capacity for soil heavy metals/metalloid and are environmentally friendly. Moreover, the combination of successive multivariate statistical analysis and SMLR provide an effective tool to predict and monitor agricultural soil heavy metals/metalloid distribution, and facilitate the improvement of environmental and territorial management.

Fish, rice, and human hair mercury concentrations and health risks in typical Hg-contaminated areas and fish-rich areas, China.

Human exposure to methylmercury (MeHg) from consuming contaminated fish has been a major concern for decades. Besides, human MeHg exposure through rice consumption has been recently found to be important in some Asian countries. China is the largest country on mercury (Hg) production, consumption, and anthropogenic emission. However, the health risks of human Hg exposure are not fully understood. A total of 624 fish, 299 rice, and 994 human hair samples were collected from typical Hg-contaminated areas and major fish-rich areas to assess the health risks from human Hg exposure in China. Fish and rice samples showed relatively low Hg levels, except the rice in the Wanshan Hg mining area (WMMA). Human hair total Hg (THg) and MeHg concentrations were significantly elevated in WMMA, Zhoushan (ZS), Xiamen (XM), Qingdao (QD), and zinc smelting area (ZSA), and 85% of hair samples in WMMA, 62% in ZS, 40% in XM, 26% in QD, and 17% in ZSA had THg concentrations exceeding the limit set by the USEPA (1 µg/g). Rice consumption was the main pathway (>85%) for human MeHg exposure in the studied Hg-contaminated areas. Meanwhile, fish was the primary human MeHg exposure source (>85%) in coastal cities. Therefore, soil remediation in typical Hg-contaminated areas and scientific guidance for fish consumption in coastal provinces are urgently needed to reduce the health risks from human Hg exposure in China.

Triad-based screening risk assessment of the agricultural area exposed to the long-term PAHs contamination.

The aim of the study was ecological risk assessment (ERA) of the agricultural soils located in the vicinity of the highly industrialized area and exposed to different emission sources of polycyclic aromatic hydrocarbons (PAHs). In this study, we demonstrated the combination of generic and site-specific ERA approach for screening assessment and delineation of the area of a high ecological risk. Generic approach was based on a hazard quotient and indicated that 62% of the research area needs further assessment. For site-specific evaluation, the Triad approach was utilized. Information from three lines of evidence (LoE): chemical, ecotoxicological and ecological, was integrated into one environmental risk (EnvRI) index. The chemical risk was derived from toxic pressure coefficients based on the total PAHs concentration. The ecotoxicological LoE included an acute toxicity testing: the luminescent bacteria Aliivibrio fischeri activity in both liquid- and solid-phase samples and the ability of crustacean Thamnocephalus platyurus to food uptake. The ecological LoE comprised microbial parameters related to soil respiration and enzymatic activity. Integrated EnvRI index ranged from 0.44 to 0.94 and was mainly influenced by high values of chemical LoE risk, while the ecotoxicological and ecological LoE indicated no or low risk. Due to the relatively high uncertainty associated with the contradictory information given by LoEs, there is the need to confirm potential risk in a tier 2 analysis.

Detection of the Freshness State of Cooked Beef During Storage Using Hyperspectral Imaging.

The freshness of meat products during storage has received unprecedented attention. This study was conducted to investigate the feasibility of a hyperspectral imaging (HSI) technique to determine the freshness state of cooked beef during storage and identify the contaminated areas on the surface of spoiled samples. Hyperspectral images of cooked beef were acquired in the wavelength range of 400-1000 nm and the freshness state of all samples was divided into three classes (freshness, medium freshness, and spoilage) using the measured total viable count (TVC) of bacteria. Fifteen feature spectra variables were extracted by random frog (RF); based on this, six optimal wavelength variables were further selected by correlation analysis (CA). Partial least squares (PLS) and least squares-support vector machine (LS-SVM) classification models were established using different spectral variables. The results indicated that the performance of the RF-CA-LS-SVM classification model with a high overall classification accuracy of 97.14%, the results of sensitivity and specificity in the range of 0.92-1, and the κ coefficient of 0.9575 in the prediction set were obviously superior to other models. Spoiled samples were further obtained using a RF-CA-LS-SVM model, and then six feature images were extracted and further fused by principal component analysis (PCA). A PC3 image was used to segment successfully the contaminated areas from normal areas of cooked beef images using the Otsu threshold algorithm. The results demonstrated that HSI has great potential in classifying the freshness of cooked beef and identifying the contaminated areas. This current study provides a foundational basis for the classification and grading of meat production in further online detection.

Biological diversity of Salix taxa in Cu, Pb and Zn phytoextraction from soil.

The aim of the study was to estimate the efficiency of copper (Cu), lead (Pb) and zinc (Zn) phytoextraction by 145 Salix taxa cultivated in an area affected by industrial activity. Survivability and biomass of plants were also analyzed. The highest Cu, Pb and Zn content in shoots was 33.38 ± 2.91 (S. purpurea × viminalis 8), 24.64 ± 1.97 (S. fragilis 1) and 58.99 ± 4.30 (S. eriocephala 7) mg kg-1 dry weight, respectively. In the case of unwashed leaves, the highest content of these metals was 135.06 ± 8.14 (S. purpurea 26), 67.98 ± 5.27 (S. purpurea 45) and 142.56 ± 12.69 (S. alba × triandra 2) mg kg-1 dw, while in washed leaves it was 106.02 ± 11.12 (S. purpurea 45), 55.06 ± 5.75 (S. purpurea 45) and 122.87 ± 12.33 (S. alba × triandra 2) mg kg-1 dw, respectively. The differences between the highest and lowest values for Cu, Pb and Zn were 545%, 20500% and 535% in shoots; 2692%, 2560% and 7500% in unwashed leaves; and 3286%, 2221% and 6950% in washed leaves, respectively. S. acutifolia was able to effectively accumulate all three metals jointly, producing shoots that were well developed in both length and diameter when compared with the other tested willows-an ability that would suggest its high suitability for practical application.

Cadmium Exposure and Potential Health Risk from Foods in Contaminated Area, Thailand.

Man-made cadmium (Cd) emissions can be transported between environmental matrices and the food chain. Food is the primary source of Cd exposure among general population as a consequence of the bio-concentration of Cd from soil. Chronic Cd exposure has been reported to be associated with chronic kidney disease, osteoporosis, diabetes, cardiovascular disease and cancer. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) established the safe level of Cd intake as provisional tolerable monthly intake (PTMI) of 25 µg/kg bw in 2010. The major food groups that contribute to the most Cd exposure are rice and grains, shellfish and sea food, meat including edible offal, and vegetables. A number of studies reported the high Cd contaminated levels in foods from polluted areas in Thailand. The results are of high concern since the contaminations occur in foods that are major Cd contributors. Thus, in this review, the current situations of Cd contaminated foods in polluted areas of Thailand are summarized. In addition, the Cd intakes from selected scenarios are estimated to assess the potential health risk to consumers and the suggestions are also included.

Predicting radiocaesium sorption characteristics with soil chemical properties for Japanese soils.

The high variability of the soil-to-plant transfer factor of radiocaesium (RCs) compels a detailed analysis of the radiocaesium interception potential (RIP) of soil, which is one of the specific factors ruling the RCs transfer. The range of the RIP values for agricultural soils in the Fukushima accident affected area has not yet been fully surveyed. Here, the RIP and other major soil chemical properties were characterised for 51 representative topsoils collected in the vicinity of the Fukushima contaminated area. The RIP ranged a factor of 50 among the soils and RIP values were lower for Andosols compared to other soils, suggesting a role of soil mineralogy. Correlation analysis revealed that the RIP was most strongly and negatively correlated to soil organic matter content and oxalate extractable aluminium. The RIP correlated weakly but positively to soil clay content. The slope of the correlation between RIP and clay content showed that the RIP per unit clay was only 4.8 mmol g(-1) clay, about threefold lower than that for clays of European soils, suggesting more amorphous minerals and less micaceous minerals in the clay fraction of Japanese soils. The negative correlation between RIP and soil organic matter may indicate that organic matter can mask highly selective sorption sites to RCs. Multiple regression analysis with soil organic matter and cation exchange capacity explained the soil RIP (R(2)=0.64), allowing us to map soil RIP based on existing soil map information.

Exposure and body burden of polychlorinated biphenyls (PCB) and metals in a historically contaminated community.

There are many small villages where environmental contamination is substantial due to historical industrial activities. The aim of the present study was to investigate if long-term or current consumption of local foods, as reported in food frequency questionnaires, co-vary with measured concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), lead (Pb), cadmium (Cd) and mercury (Hg) in blood, urine and hair from a population living in a historically contaminated village. Blood, urine and hair were provided by men (n=38) and women (n=57), who had participated in a previous case-control study in the contaminated area, and were analyzed for PCB, OCPs, Pb, Cd and Hg. A detailed food frequency questionnaire, used in the previous epidemiological study, was repeated, and up-dated information of life-style, exposure factors and other covariates was collected. Associations between reported consumption of local foods and exposure biomarkers were explored in relation to age, gender, life-style factors and other covariates. A large part of the population in the area reported consumption of local food, and thus, was potentially exposed to the contaminants. Despite the limited number of participants and other weaknesses described, it was possible to link reported consumption of different foods to biomarker concentrations. Reported consumption of local vegetables, forest berries and mushrooms co-varied with urinary Cd, indicating an influence from the contaminated area on the Cd exposure. We found no associations between PCB plasma concentrations with reported consumption of local fish, but with consumption of herring (non-local sea fish) which is typically high in PCB. Pesticide (HCB, p,p'-DDE, trans-nonachlor) exposure was mainly associated with agricultural work and having a private well the first five years of life, but we found no associations between pesticide concentrations in plasma and consumption of local vegetables or fish. Exposure to Hg was associated with consumption of fish, both local and non-local, and Pb exposure was associated with the consumption of game. Overall, the contaminant concentrations measured in blood, urine and hair varied substantially among study participants, but on average, the concentrations were similar to concentrations measured in other groups of the general Swedish population in the same age range. Larger studies are needed to evaluate health risks (and causality) associated with historical environmental contamination.

Dose- and age-dependent cardiovascular mortality among inhabitants of the Chornobyl contaminated areas. 1988-2010 observation period. / Smertnist'' vid hvorob systemy krovoobigu meshkanciv radioaktyvno zabrudnenyh terytorij ukrai'ny vnaslidok avarii' na chaes zalezhno vid doz radiacijnogo oprominennja ta viku. 1988-2010 roky sposterezhennja.

Objective. The goal of this study was to conduct a descriptive epidemiological analysis of cardiovascular disease mortality among people living in contaminated areas of Ukraine with regard for total cumulative effective doses and age at the time of the Chornobyl accident. Materials and methods. Depending on respective total cumulative effective doses for 1986-2010 the people living in contaminated areas of Ukraine were divided into cohorts of those exposed to 5.6-20.99 mSv (cohort 1) and 21.00-50.99 mSv (cohort 2) radiation doses. Each one was stratified by age categories - younger than 18 years old, aged 18-39 and 40-60 respectively. Death rate (ID/10^3 person-years) and mean error (±m) were calculated and Student's test (t) was applied to estimate the mortality from cardiovascular diseases for 1988-2010 period. Results. The significantly higher (ID/10^3 person-years is 8.08 ± 0.10) cardiovascular disease mortality was revealed within 1988-2010 observation period among inhabitants of contaminated areas exposed to 21.00-50.00 mSv total effective radiation doses accumulated over 1986-2010 as compared to that in cohort 1 (ID/10^3 person-years is 6.29 ± 0.06) for the same period. In the age groups (under 18, 18-39 and 40-60 years old) exposed to 21.0-50.0 mSv doses the mortality rate was significantly higher than in the corresponding age groups of the inhabitants with 5.6-20.99 mSv exposure (1.31 ± 0.08 ID/10^3 person-years, 8.50 ± 0.19, 48.95 ± 0.33 vs 0.75 ± 0.04, 5.00 ± 0.11, 23.52 ± 0.24 respectively). In the elder age groups with higher radiation doses the mortality was significantly higher (p < 0.05) than in those with lower doses: ID/10^3 person-years was 1.31 ± 0.08 vs. 0.75 ± 0.04 (those under 18 years); 8.50 ± 0.19 vs. 5.00 ± 0,11 (those aged 18-39); 48.95 ± 0.33 vs. 23.54 ± 0.24 (people aged 40-60). Among inhabitants with higher radiation doses the mortality rates for certain groups of cardiovascular diseases (coronary heart disease, cerebrovascular disease, arterial hypertension, diseases of arteries, arterioles and capillaries) were significantly higher compared to those having lower radiation doses. Conclusions. Cardiovascular mortality among inhabitants of contaminated areas of Ukraine is dependent on the total cumulative effective doses and age at the time of the Chornobyl accident. It is proved by a significantly higher (p < 0.05) mortality in people exposed to 21.00-50.0 mSv radiation doses compared to those having 5.6-20.99 mSv exposures. Mortality was significantly higher (p < 0.05) in age groups with higher doses as opposed to those with low ones. Maximum mortality was observed among inhabitants aged 40-60, while the lowest death rate in patients younger than 18 years old. The data obtained also suggest that the radiation factor can be considered here as one accelerating the aging and pathophysiological abnormalities in survivors. Coronary heart disease, cerebrovascular disease, arterial hypertension, diseases of arteries, arterioles and capillaries are the main causes of death from cardiovascular disease in people under investigation.

Assessment of mercury erosion by surface water in Wanshan mercury mining area.

Soil erosion is a main cause of land degradation, and in its accelerated form is also one of the most serious ecological environmental problems. Moreover, there are few studies on migration of mercury (Hg) induced by soil erosion in seriously Hg-polluted districts. This paper selected Wanshan Hg mining area, SW China as the study area. Revised universal soil loss equation (RUSLE) and Geographic information system (GIS) methods were applied to calculate soil and Hg erosion and to classify soil erosion intensity. Our results show that the soil erosion rate can reach up to 600,884tkm(-2)yr(-1). Surfaces associated with very slight and extremely severe erosion include 76.6% of the entire land in Wanshan. Furthermore, the cumulative erosion rates in the area impacted by extremely severe erosion make up 90.5% of the total. On an annual basis, Hg surface erosion load was predicted to be 505kgyr(-1) and the corresponding mean migration flux of Hg was estimated to be 3.02kgkm(-2)yr(-1). The erosion loads of Hg resulting from farmland and meadow soil were 175 and 319kgyr(-1) respectively, which were enhanced compared to other landscape types due to the fact that they are generally located in the steep zones associated with significant reclamation. Contributing to establish a mass balance of Hg in Wanshan Hg mining area, this study supplies a dependable scientific basis for controlling soil and water erosion in the local ecosystems. Land use change is the most effective way for reducing Hg erosion load in Wanshan mining area.

Mercury in food items from the Idrija Mercury Mine area.

As a consequence of over 500 years of mining and smelting activities (1490-1995), and of its natural geological occurrence, the soil in the Idrija region is highly contaminated with Hg. In order to assess the present situation regarding the Hg levels in local food samples, concentrations of total mercury (THg) and monomethyl mercury (MeHg) were determined in selected vegetables, mushrooms and fish from the Idrija Hg mine area. Hg levels in the foodstuffs analysed were not very high but were elevated compared to the levels in food from non-contaminated areas. The study showed that THg accumulates in mushrooms (X=5680ng/g dry weight, Min=346ng/g dry weight, Max=17,100 dry weight) and chicory (X=1950ng/g dry weight, Min=86ng/g dry weight, Max=17,100ng/g dry weight). In addition, Se and Cd concentrations were determined by ICP-MS in those vegetable and mushroom species in which the highest Hg levels were found. The levels of Cd and Se were below the threshold levels. Based on data from previous studies, we can conclude that the levels of Hg in food have not diminished significantly during the past 15 years after closure of the Hg mine. Special attention should be given to vegetables such as chicory, representing a local seasonal vegetable eaten frequently.

Radiation dose- and sex-dependent cardiovascular mortality in residents of contaminated areas after the Chornobyl NPP accident, 1988-2010 observation period.

OBJECTIVE: To estimate the circulatory system disease death rates for people living in areas contaminated after the Chornobyl accident. Epidemiological estimation covered the post-accident period (1988-2010) and was focused on the relationship between death rates and doses accumulated over 1986-2010 or sex of survivors aged under 60 at the time of the accident. MATERIALS AND METHODS: We used data from the State Registry of Ukraine on persons affected by the Chornobyl accident. Residents of contaminated areas were grouped into the two cohorts according to cumulative dose values. Cohort 1 numbered 155,592 people (86,787 females and 68,805 males), their radiation doses were 5.6-20.99 mSv; cohort 2 totaled 98,830 people (52,640 females and 46,190 males) with radiation doses 21.00-50.99 mSv. Mean age (X ± δ) of inhabitants of contaminated areas at the time of the accident (April 26, 1986) was 29.5 ± 23.2 years (30.6 ± 22.3 for women and 28.3 ± 23.2 for men) in the cohort 1, and 28.7 ± 17.3 years (29.8 ± 17.7 and 27.5 ± 16.2 respectively) in the cohort 2). These cohorts were subdivided by sex (males and females). RESULTS: Significantly higher (ID per 103 person-years is 8.08 ± 0.10) cardiovascular mortality was revealed among members of the cohort 2 vs. cohort 1 (ID per 103 person-years is 6.29 ± 0.06). Mortality from cardiovascular diseases in both sex groups of the cohort 2 is higher (ID per 103 person-years is 6.80 ± 0.12 in women and 9.43 ± 0.15 - in men) than that of the cohort 1 (ID per 103 person-years is 5.34 ± 0.08 in women, 7.37 ± 0.10 - in men). Whatever accumulated doses the mortality from circulatory diseases was significantly higher in men vs. women. CONCLUSION: Cardiovascular mortality in population of radiation-contaminated territories depends on the integral radiation exposure and gender. Death rates are clearly higher (p<0.05) in persons having more radiation doses vs. those exposed to less ones. Mortality is significantly higher in males vs. females despite integral radiation doses values. The coronary heart disease, cerebrovascular disease, arterial hypertension, heart diseases, diseases of arteries, arterioles and capillaries) were the main causes of death.

Transmission of communicable respiratory infections and facemasks.

BACKGROUND: Respiratory protection efficiency of facemasks is critically important in the battle against communicable respiratory infections such as influenza and severe acute respiratory syndrome (SARS). We studied the spatial distributions of simulated virus-laden respiratory droplets when human subjects wore facemasks and were exposed to regulatory viral droplets by conducting in vivo experiments in facemask use. METHODS: Transmission pathway of aerosols of Fluorescein-KCl solution through facemasks and protective efficiency of facemasks were examined by using normal surgical facemasks and two facemasks with exhaust valves (Facemask A) and exhaust holes (Facemask B) covered with the same surgical filters situated at the back of the facemasks. Fluorescein-KCl solution was sprayed onto the faces of participants wearing the facemasks and performing intermittent exercises on a treadmill in a climatic chamber. RESULTS: Experimental results showed that when droplets spread onto a person face-to-face over short distances, 92.3% to 99.5% of droplets were blocked by the front surface of the facemask, whereas only 0.5% to 7.7% of droplets reached the back of the facemask. Both facemasks A and B had near or over 99% protection efficiency, compared with that of 95.5% to 97% of surgical facemasks. Using the same filters as normal surgical masks, facemasks A and B provided more effective respiratory protection against communicable respiratory infections such as influenza and SARS by the location of the breathing pathway to the back of the facemasks. CONCLUSIONS: Separating the breathing pathway from the virus-contaminated area in facemasks can provide more effective protection against communicable respiratory infections such as influenza and SARS.