Average Pb Research Articles

Small chamber study of lead exposures from manual soldering of microelectronics

Airborne and surface Pb concentrations were measured inside a glovebox chamber with controlled inflow rate at 1.0 L/min of ultrapure air over a 4-hour period while an operator completed 1,680 solder connections using Sn63:Pb37 solder with rosin flux core. Chamber atmosphere showed released mean Pb mass of 0.0238 ± 0.011 μg and mean airborne concentration of 0.176 ± 0.085 μg/m3. Of the total solder mass used in two trials, on average 4.65% was recovered from the tip cleaning sponge and 0.14% dropped onto the work surface, with a surface loading rate of 0.30–0.45 μg/cm2. The estimated fingertip surface area in contact with solder wire was 14.7 cm2, with a measured average Pb mass of 14.9 μg, and a corresponding dermal loading rate of 1.01 μg/cm2. The waste solder dross surface area determined from digital micrographs in each trial were 1.65 and 2.43 cm2, with corresponding Pb density of 714 and 610 mg/cm2 and >90% of the detected dross mass comprising particles >100 μm in the widest dimension. Corresponding increases in blood Pb levels estimated using physiologically-based pharmacokinetic modeling were negligible compared with background. These findings demonstrate very low Pb emissions to air and surfaces during intensive manual microelectronic soldering activities.

Assessment of the health risks of heavy metals in soils and vegetables from greenhouse production systems in Iran

Overuse of chemical and organic fertilizers in greenhouse (GH) crop production may cause the accumulation of heavy metals in soils and risks to human health. The aims of this study were to compare physical and chemical properties of GH with open-field (OF) soils, to clarify the buildup of heavy metals and phosphorus (P) in soils, and to assess the risks of selected heavy metals in soils and cucumber (Cucumis sativus L.) and tomato (Lycopersicon esculentum Mill.) from GH vegetables in Hamedan, western Iran. The average total and Olsen P of GH soils were significantly higher than the OF soils for both vegetables. The order of total and available heavy metal content in tomato GH soils has been set as zinc (Zn) > nickel (Ni) > chromium (Cr) > lead (Pb) > copper (Cu) > cadmium (Cd) and Zn > Cr > Cu > Pb > Ni > Cd, respectively. The same order was found for cucumber GH soils, except that the position of Pb and Cu was changed. The results indicated that in both GH cucumber and tomato soils, the mean content of total and available Zn, available Cu, Ni, and Pb, was extra than in OF soils. There were no significant differences between average total Cr, Cu, Ni, and Pb in GH and OF soils. Tomato vegetables had higher heavy metal content and transfer factors, particularly for Cr than cucumber vegetables. According to the health risk indices, Cr and Pb represented a high potential risk for health through cucumber and tomato consumption. There were limited Cd, Cu, Pb, and Zn inputs from the irrigation waters, while the input of Cr and Ni may be important. However, the amount of manure application and heavy metal content of the manures was significant.

Urban geochemical changes and pollution with potentially harmful elements in seven Russian cities

This paper presents results of an analysis of potentially harmful elements (PHEs, Pb, Zn and Cu) and conservative element (CE, Fe) concentrations in urban surface deposited sediment (USDS). The study was conducted in seven large Russian cities located in different geographic and climatic zones, and in territories with different geology and anthropogenic pressures: Chelyabinsk, Magnitogorsk, Nizhniy Novgorod, Nizhniy Tagil, Rostov-on-Don, Tyumen, and Ufa. The initial geochemical baseline relationships between PHEs and CE concentrations in the USDS were reconstructed for each city applying an approach based on linear weighted fitting of PHE as a function of CE with lower weights assigned to more polluted samples. The reconstructed average initial baseline Pb, Cu, and Zn concentrations varied between 17–52, 25–196, and 91–413 mg kg−1, respectively. Several new criteria for assessing the degree of geochemical transformation and pollution of the urban environment, such as the percentage of polluted samples, average pollutant concentration in polluted samples, and weighting degree index δ, were suggested and compared with common criteria, such as the PHE concentration and the geo-accumulation index. The environmental rank of a city significantly differed depending on whether the criterion for ranking was total PHE pollution or changes in comparison with the initial geochemical baseline.

Spatial Distribution and Bio-accumulation of Cadmium and Lead in Soil, Rice and Vegetables in Typical Pollution Areas, China

The adverse effects of Cd and Pb on human health have been widely reported. While, there were several typical pollution areas in China which has not been investigated comprehensively and deeply. In this study, 475 soil and 472 plant samples from these pollution areas were analyzed for Cd and Pb with ICP-MS. Here, the pollution levels of different areas were analyzed and compared; the spatial distributions in soil, rice and cabbage samples were illustrated in map; and the relationships of Cd and Pb in soil and rice, soil and cabbage were also discussed. The results showed that Cd pollution still existed in some south, central-south and south-east zones except other three zones located in suburb of Tianjin, north-east and north China which might be explained by the higher background values, soil acidity, Karst landscape and metallurgy industry. Comparatively, the Pb concentrations showed lower over-standard rate. Moreover, the spatial distribution of Cd and Pb in rice and cabbage showed similar trends with those of soil samples. Particularly, the average Cd and Pb concentrations in lettuces were much higher than those in other plants. Cd and Pb concentrations in rice and cabbage showed low linear dependence with the concentrations in soil. The results in this study added basic environmental data and would be helpful to future soil remediation of these areas.

Heavy metal contamination in tilapia, Oreochromis niloticuscollected from different fish markets of Mymensingh District

The study was conducted to determine heavy metals viz; lead (Pb), Zinc (Zn), Arsenic (As), Chromium (Cr), and Cadmium (Cd) concentration in tilapia (Oreochromis niloticus) collected from different fish markets (Borobazar fish market, Shesmore fish market, Kamal-Ranjit market, Sutiakhali fish market, Machuabazar fish market and Shamvuganj fish market) of Mymensingh district from July 08, 2018 to January 15, 2019. After collection, electro-thermal heater digestion of the samples was carried out in Nutrition Laboratory, Department of Aquaculture, Bangladesh Agricultural University (BAU) and finally heavy metal concentrations were determined by Atomic Absorption Spectrometer (AAS) in the Interdisciplinary Institute for Food Security (IIFS) Laboratory, BAU. The average Pb, Zn, Cr, and Cd concentrations (mg/kg) in the examined samples were 1.67 mg/kg, 118.68 mg/kg, 0.97 mg/kg, and 0.59 mg/kg, respectively. The average Arsenic concentrations in all tilapia samples were found to be below detectable limit (BDL). The study revealed that the average Zn and Cr concentration of tilapia flesh samples in Mymensingh were considerably higher than maximum recommended limit of World Health Organization (1989) and Food and Agricultural Organization (1983) and hence human health safety issues for the local consumer should be taken into consideration by the concerned authorities.

Novel combined amendments for sustainable remediation of the Pb-contaminated soil

Pressures exerted on the soil ecosystem due to its exposure to lead have a significant and aggravating effect on the quality of life. This study was conducted to investigate the aided phytostabilization of Pb-contaminated soils by novel combined amendments. The pot experiment was run under greenhouse conditions, using the following mixtures of immobilizing amendments: halloysite and limestone as well as halloysite and compost. The Pb contents in plants, both total and CaCl2-extractable Pb concentration in soil, were determined using the spectrophotometric method. The use of halloysite and compost was shown to be the most effective and decreased the average Pb content in the above-ground parts of F. rubra and in the soil and was found to significantly increase soil pH and Pb content in roots of the test plant. New methods should be developed to minimize the environmental risk posed by the presence of heavy metal pollutants. The results show significant effects of immobilizing amendments on the chemical characteristics of soil contaminated with Pb and the uptake of Pb by plants.

Removal of Heavy Metals and Nutrients from Municipal Wastewater using Salvinia molesta and Lemna gibba

The present study was focused on the investigation of the abilities and efficiencies of Salvinia molesta and Lemna gibba to remove selected heavy metals (Cr, Cu, Fe, Ni and Pb) and excess nutrients from wastewater taken from the Moratuwa-Ratmalana municipal wastewater treatment plant. The wastewater samples were analysed for pH, Temperature, for N-Nitrates, N-Nitrites, ammonia Nitrogen, Phosphates, and selected heavy metals, Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD) and Total Kjeldhal Nitrogen. Then, the wastewater samples were treated with S. molesta and L. gibba separately for a period of 7 days and analysed for N-Nitrates, N-Nitrites, Ammonia Nitrogen, Phosphates and five selected heavy metals at 24 hour intervals. BOD, COD and Total Kjeldhal Nitrogen were analysed at 7 days intervals. The average Total Nitrogen removal efficiencies of S. molesta and L. gibba were 73.3% and 62.1% whereas the average Total Phosphate removal efficiencies of S. molesta and L. gibba were 72.6% and 77.2% respectively. The average Cr, Cu, Fe, Ni and Pb removal efficiencies of S. molesta were 81.6%, 69.8%, 65.2%, 66.3% and 74.8% respectively. The average Cr, Cu, Fe, Ni and Pb removal efficiencies shown by L. gibba were 86.9%, 69.7%, 73.1%, 61.8% and 85.7% respectively. The Bio Concentration factors of S. molesta for Cr, Cu, Fe, Pb and Ni were 823, 698, 652, 663 and 748 respectively and the Bio Concentration factors of S. molesta for Cr, Cu, Fe, Pb and Ni were 870, 698, 731, 618 and 857 respectively. According to the obtained results in the present study S. molesta and L. gibba can be considered as suitable candidates for the polishing of municipal wastewater.

Trace metals in surface soils under different land uses in Kielce city, south-central Poland

This work presents the influence of land use in Kielce on the spatial differentiation of heavy metals in the near-surface soil layer. The aim is to determine the amounts of ten trace elements (As, Ba, Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn) contained in soil samples of five land use categories (residential areas, roads, urban greenery, allotment gardens, agricultural areas) in the city and to evaluate the contamination using geochemical indicators. The Clarke values of Earth’s crust and the average content of the elements in Poland’s soils are exceeded only for Pb and Zn (N = 60). Soils of urban greenery and residential areas stand out in this respect. Particularly noteworthy is the fact that a high content of As has been documented in the soils of allotment gardens and confirmed by high values of the geoaccumulation index (moderate to high pollution) in relation to the Clarke values and to average contents in Poland's soils. The highest average Pb content has been found in the areas of urban greenery and residential areas. The integrated pollution index (IPI) in terms of maximum values indicates high level of metal pollution of soils in all forms of land use, except for agricultural areas (moderate). On average, IPI and potential ecological risk index are low.

Growth Responses and Accumulation Characteristics of Three Ornamentals Under Copper and Lead Contamination in a Hydroponic-Culture Experiment.

A hydroponic experiment was carried out to study the accumulation characteristics of copper (Cu) and lead (Pb) combined pollution in three ornamental plants. The results showed that these tested ornamental plants had higher tolerance to Cu-Pb combined pollution and could effectively accumulate the heavy metals. The Cu and Pb concentrations were higher in the roots of the ornamental plants than that in the shoots. For Panax notoginseng (P. notoginseng), Chlorophytum comosum (C. comosum) and Calendula officinalis (C. officinalis), the average Cu and Pb concentration in the three ornamental plants were 1402.1mg/kg, 829.5mg/kg, and 1473.4mg/kg for Cu and 2710.4mg/kg, 4250.3mg/kg, and 4303.6mg/kg for Pb, respectively. The three ornamental plants accumulation and tolerance to Cu-Pb were demonstrated through the hydroponic-culture method in this study. Therefore, the three ornamental plants should have great potential to be used in remediation of soils contaminated by Cu and Pb and beautifying the environment simultaneously.

Copper, zinc and lead isotope signatures of sediments from a mediterranean coastal bay impacted by naval activities and urban sources

Toulon bay is severely impacted by metal contamination induced by past and recent naval activities. In this work, Cu, Zn and Pb isotope compositions and elemental concentrations of fifty-five surface sediments were determined in order to map the spatial distribution of anthropogenic and natural sources along this land-sea continuum. Two sub-systems of Toulon Bay, the Small and Large bays, showed well-marked patterns on metal contamination levels and isotope signatures for Cu and Pb. The Small bay had the highest metal concentrations, and displayed average Pb and Cu isotope compositions of 1.1664 ± 0.0043 (1s, expressed as 206Pb/207Pb ratios) and −0.17 ± 0.19‰ (1s, expressed as δ65CuNIST values), respectively. It contrasted with the Large bay, with moderate to pristine metal concentrations and average Pb and Cu isotope compositions of 1.1763 ± 0.0079 (1s) and +0.08 ± 0.23‰ (1s), respectively. Lead isotope systematics indicated a binary source mixing process involving industrial and natural sources, while Cu isotope systematics showed a ternary mixing process involving two distinct anthropogenic signatures, interpreted as associated to new diffuse anthropogenic sources and old warfare material. In contrast, Zn isotope compositions in the Small and Large bays were practically the same: +0.06 ± 0.05‰ and +0.06 ± 0.11‰ (1s, expressed δ66ZnJMC values), respectively, denoting an overlap between isotope signatures of natural and anthropogenic sources. This study presents the first detailed spatial distributions of Cu and Zn isotope compositions for an aquatic system, and demonstrates the feasibility to use Cu isotopes as tracers of anthropogenic sources in coastal environments.

Rb-Sr isotopic age, S-Pb-Sr isotopic compositions and genesis of the ca. 200 Ma Yunluheba Pb-Zn deposit in NW Guizhou Province, SW China

Over 400 carbonate-hosted Pb-Zn deposits in the western Yangtze block constitute the giant Sichuan-Yunnan-Guizhou (SYG) Pb-Zn metallogenic province. The majority of Pb-Zn deposits hosted in Devonian carbonates are characterized by low δ34S values, causing debates on their ore genesis. To address this issue, the Yunluheba Pb-Zn deposit is chosen as a case study. Ore bodies of this deposit are hosted in middle Devonian carbonates. Ore minerals are sphalerite, galena and pyrite. Sphalerite Rb-Sr dating yields an isochron age of 206.2 ± 4.9 Ma, consistent with ages of most Pb-Zn deposits in the SYG province, arguing for a regional intensive Pb-Zn mineralization event during the late Indosinian orogeny. Sulfides have Pb isotopic compositions that form a linear trend above the average crustal Pb growth curve in the 207Pb/204Pb vs. 206Pb/204Pb plot. Moreover, Pb isotopic ratios are consistent with the Devonian to Permian carbonates’ age-corrected Pb isotopic ratios, suggesting mixed crustal Pb sources with the majority of Pb derived from country rocks. Combined with initial 87Sr/86Sr ratios of sphalerite, approximately equal to 87Sr/86Sr200Ma ratios of the D-P carbonates, ore-forming metals are considered to have been derived mainly from ore-hosting rocks. Sulfides’ δ34SCDT values range mainly from −2.0‰ to 2.9‰, interpreted to be a result of mixing by syn-sedimentary pyrite originated biogenic S and thermochemically reduced S. We conclude that the Yunluheba deposit and other Pb-Zn deposits in the SYG province should belong to Mississippi Valley-type deposits.

Effect of soil pH and organic matter content on heavy metals availability in maize (Zea mays L.) rhizospheric soil of non-ferrous metals smelting area.

Maize plant tissues and rhizosphere soil were collected from an agricultural area around the Huludao Zinc Plant in Liaoning Province, China, to investigate the effects of soil pH and organic matter content on heavy metal concentration and accumulation in different types of maize tissues. The mean pH of the soil samples was 7.02 (range 5.74-7.86), and the mean organic matter content was 31.03gkg-1 (range 18.80-52.20gkg-1). The average Cu, Zn, Pb, and Cd contents in soil were 2.92, 6.72, 7.95, and 16.28 times greater than the corresponding background values, respectively. The geo-accumulation index indicated that the soils were uncontaminated to moderately contaminated by Cu, moderately to strongly contaminated by Pb and Zn, and strongly contaminated by Cd. The average available Cu, Pb, Zn, and Cd contents in the soil samples were 16.34, 6.997, 69.77, and 0.190mgkg-1, respectively, while their bioavailability coefficients were 28.53%, 1.65%, 40.44%, and 10.83%, respectively. The respective mean Pb and Cd concentrations in grain samples were 0.341 and 0.342mgkg-1, which exceeded the maximum concentrations permitted by the Chinese National Standard. Thus, the maize grain is not safe for consumption and poses potential risks to human health. With the exception of Cu, the combined effect of pH and organic matter content had a stronger influence on the availability of heavy metals in soil compared with either factor alone. Cd uptake in maize plant tissues was affected by the combination of soil pH, organic matter content, and bioavailable Cd content in soil; however, the combination of these three factors had only slight effects on Cu, Zn, and Pb absorption in maize tissues.

Turmeric means “yellow” in Bengali: Lead chromate pigments added to turmeric threaten public health across Bangladesh

Adulteration is a growing food safety concern worldwide. Previous studies have implicated turmeric as a source of lead (Pb) exposure due to the addition of lead chromate (PbCrO4), a yellow pigment used to enhance brightness. We aimed to assess the practice of adding yellow pigments to turmeric and producer- consumer- and regulatory-factors affecting this practice across the supply chain in Bangladesh. We identified and visited the nine major turmeric-producing districts of Bangladesh as well as two districts with minimal turmeric production. In each district, we conducted semi-structured interviews and informal observations with individuals involved in the production, consumption, and regulation of turmeric. We explored perceptions of and preferences for turmeric quality. We collected samples of yellow pigments and turmeric from the most-frequented wholesale and retail markets. We collected samples of turmeric, pigments, dust, and soil from turmeric polishing mills to assess evidence of adulteration. Interviews were analyzed through an inductive, thematic coding process, with attention focused on perceptions of and preferences for turmeric quality. Samples were analyzed for Pb and chromium (Cr) concentrations via inductively coupled plasma mass spectrometry and x-ray fluorescence. In total, we interviewed 152 individuals from across the supply chain and collected 524 samples of turmeric, pigments, dust, and soil (Table S3, Table S4). Turmeric Pb and Cr concentrations were highest in Dhaka and Munshiganj districts, with maximum turmeric powder Pb concentrations of 1152 μg/g, compared to 690 μg/g in the 9 major turmeric-producing districts. We found evidence of PbCrO4-based yellow pigment adulteration in 7 of the 9 major turmeric-producing districts. Soil samples from polishing mills contained a maximum of 4257 μg/g Pb and yellow pigments contained 2–10% Pb by weight with an average Pb:Cr molar ratio of 1.3. Turmeric wholesalers reported that the practice of adding yellow pigments to dried turmeric root during polishing began more than 30 years ago and continues today, primarily driven by consumer preferences for colorful yellow curries. Farmers stated that merchants are able to sell otherwise poor-quality roots and increase their profits by asking polishers to adulterate with yellow pigments. Adulterating turmeric with lead chromate poses significant risks to human health and development. The results from this study indicate that PbCrO4 is being added to turmeric by polishers, who are unaware of its neurotoxic effects, in order to satisfy wholesalers who are driven by consumer demand for yellow roots. We recommend immediate intervention that engages turmeric producers and consumers to address this public health crisis and ensure a future with Pb-free turmeric.

Effects of Atmospheric Fallout on Lead Contamination of Wheat Tissues Based on Stable Isotope Ratios.

In order to trace the source of Pb pollution in wheat, the contribution ratio of soil and atmospheric fallout source was quantified based on stable isotope ratios. Results showed that the average Pb content of soil was significantly lower than that of fallout, and Pb in the fallout had a higher weak acid fraction than soil. Pb in wheat had a distinct distribution in its tissues and the content of Pb in wheat roots was significantly higher than it in shoots. The 206Pb/207Pb ratio of soil was significantly higher than that in atmospheric fallout (p< 0.05). According to a binary mixing model, the 206Pb/207Pb ratio in wheat roots, leaves, and grains reflect 67%, 65%, and 90% of Pb content contributions from fallout, respectively. This results suggest that fallout Pb was absorbed by wheat leaves and transferred to other organs, and it is important to develop effective strategies to control fallout Pb risks.

Characteristic concentrations and isotopic composition of airborne lead at urban, rural and remote sites in western Korea

Anthropogenic Pb emitted from East Asia, particularly China, is often long-range transported to the east by the prevailing westerlies. To characterize the geographical properties of varying atmospheric Pb concentrations by transboundary and domestic source(s)-related Pb in Korea, closely adjacent to China, the Al and Pb concentrations and the stable Pb isotopic composition were determined in the total suspended particles (TSP) collected at urban (IC), rural (TA), and remote background (JJ) sites in western Korea from August 2015 to October 2016. The annual average Pb concentrations were significantly higher in urban and rural areas (IC, 16.2 ng m−3 and TA, 11.1 ng m−3) than in remote area (JJ, 6.41 ng m−3), showing pronounced seasonal variations with relatively higher concentrations in winter and spring and lower concentrations in summer and autumn. Significantly high enrichment factors (EF) for Pb indicate that anthropogenic contributions are important for this toxic element in TSP. Coupling the Pb isotopic signatures with the air mass back trajectories identified the major potential source regions for individual samples. The results show that during winter, China was the dominant contributor, accounting for 92%, 82%, and 100% of the sampling periods at IC, TA, and JJ, respectively. The Chinese contribution decreased in summer and autumn, whereas the Korean contribution increased, according to the East Asian monsoon system. The Pb concentrations increased by 2.2 (IC), 1.2 (TA) and 1.4 (JJ) times when the Chinese contribution was dominant, compared to the Korea-dominant periods. The Pb isotopic systematics for the samples characterized by the dominant Korean contribution differed substantially between the three sites, implying that the relative importance of various domestic sources varied with geographical areas in western Korea.

Moss facilitating mercury, lead and cadmium enhanced accumulation in organic soils over glacial erratic at Mt. Gongga, China

Moss is usually as an initial colonizer in alpine glacier retreated regions. We hypothesized that moss can significantly facilitate the toxic metals accumulation in alpine ecosystems based on its strong ability of absorption and the role in soil development. Hence, we investigated the trace element pool sizes and enrichment factors, especially for mercury (Hg) by using the Hg isotopic compositions to determine the source contributions in a moss-dominated ecosystem over glacial erratic in Eastern Tibetan Plateau. Results show that Hg, lead (Pb) and cadmium (Cd) are highly enriched in organic soils. Specifically, Cd concentration is 5–20 times higher than the safety limit of the acid soil (pH ≤ 5.5) in China. Atmospheric depositions dominantly contribute to the Pb and Cd sources in organic soils, and followed by the moraine particles influences. The lowering pH in organic soils increasing with glacial retreated time results in the desorption of Cd in organic soils. Atmospheric Hg0 uptake by moss predominantly contributes to the Hg sources in organic soils. The average Pb accumulation rate over last 125-year is about 5.6 ± 1.0 mg m−2 yr−1, and for Cd is 0.4 ± 0.1 mg m−2 yr−1, and for Hg0 is 27.6 ± 3.2 μg m−2 yr−1. These elevated accumulation rates are caused by the high moss biomass and elevated atmospheric Hg, Pb and Cd pollution levels in China and neighbouring regions. Our study indicates that the moss not only as the bioindicator, but also plays an important role in the hazardous metal biogeochemical cycling in alpine regions.

Lead and cadmium in foods/drinking water from Slovenian market/taps: Estimation of overall chronic dietary exposure and health risks

ABSTRACTApproximately 3000 food samples from the Slovenian market and 2500 drinking (tap) water samples in the period 2011 − 2016 were evaluated for the presence of toxic elements lead (Pb) and cadmium (Cd) and the overall chronic dietary exposure was assessed for each element. The highest mean concentrations were found for Pb in products for special nutritional use – dietary supplements (0.383 mg/kg) and for Cd in fish and seafood (0.117 mg/kg). The consumption data were obtained from the national study of the household budget and from the European Food Safety Authority (EFSA) summary statistics. Chronic dietary exposure was estimated deterministically. The average Pb and Cd intakes from food and drinking (tap) water ranged for children from 0.90 to 1.021 µg/kg bw/day and 4.65 to 5.65 µg/kg bw/week, respectively, and for adults, including adolescents, from 0.40 to 0.53 µg/kg bw/day and 1.98 to 2.82 µg/kg bw/week, respectively. The high consumption of cereal-based foods and vegetables contributed most to overall Pb and Cd intake in the majority of the age groups. The exposure to Pb was generally lower and that to Cd was higher compared to the average EU values. The most exposed were children, as the health-based guidance values were exceeded for both elements, which indicates a health concern. An important contribution to Cd exposure can be attributed to grains and potatoes grown in Slovenia, where the soil contains more Cd than that in other EU countries. Further efforts to reduce Pb and Cd intake are required to minimize potential health risks.

Estimations of heavy metals in soils and different landscape components within the municipal solid waste disposal areas

The comprehensive geoecological study of the area closed to the north-western part of Landfill No 5 for the municipal solid waste disposal shows the ecologically negative impact on the environment. It is determined that the existing soils are affected by the significant geochemical transformation. They are characterized by the considerable accumulations of the heavy metals (HMs). In comparison with the conventional pure soils the soil contents of Cu, Zn, Ni, Cr and Pb are 8, 12, 3, 2, 17 times more, respectively.The anomalous high HMs pollution for the bottom deposits is identified: for Zn – in 800 mg/kg that is 14 times more than maximum allowable concentrations (MAC); for Cu – 150 mg/kg that is 4.5 times more than MAC. Average Pb content there exceeds its MAC and is equal to 72 mg/kg. Therefore, the bottom deposits have the hazardous level of pollution.It is shown that the elements of considerable accumulations in grass vegetation are Cu, Cr and Ni at the biological absorption coefficient more 2.0.The physical and chemical studies of surface waters show that the contents of microelements (F, Cr, Ni, Cu, Fetot. and Pb) there don’t exceed the MAC, but they are higher than the background values.The comparison of the average chemical composition for the ground water samples from the wells of the Landfill area and the regulatory standards indicates that the standard general sanitary criteria for pollution level of these waters belong to the middle and high levels with the considerable exceeds of the MACs for Fe and Ni.

Remediation effect of biochar-plant on heavy metal contaminated soil in mining area

Pot experiment was carried out to artificially add different concentrations (0%, 5%, 10%) of swine biochar and fruit biochar in heavy metal contaminated soil in the farmland of the mining area to study the repairing effect on heavy metal contaminated soil. The results showed that the total Cu of the tested soil before planting was 166.51 mg/kg, the average Cd was 1.31 mg/kg, the average Pb was 757.78 mg/kg, and the average Hg was 8.43 mg/kg, which was a mixed contaminated soil of mercury, lead, cadmium and copper. The contents of Hg and Pb of the tested soils decreased after planting 4 plants, and Cd content decreased in addition to the CK group. The Cu content in the Z10 group decreased, but Hg content still exceeded the soil risk control value, the Cu, Cd and Pb contents exceeded the risk screening value, and the potential risk was reduced but still existed. Compared with CK treatment, the two biochars have better remediation effects on the 4 heavy metals in the tested soil, and the swine biohar was better than the fruit biochar. With the increase of the concentration of the two biochars, the repair effect was better. In the combined pollution soil, the overall remediation effect of biochar-plant combined restoration on these four heavy metals was Hg > Pb > Cd > Cu, and Z10-pakchoi had the best repair effect on Hg, Pb and Cu in the tested soil. Z10-spinach had the best effect on the repair of Cd.

Contamination and ecological risk assessment of heavy metals pollution from the Shalateen coastal sediments, Red Sea, Egypt

To assess the contamination and ecological risk assessment of the Shalateen coastal sediments, Red Sea, Egypt, 35 samples were collected to analyze Cu, Sr, Zn, Cd, Pb, Fe, Co, Ni, Mn, and total organic matter with an atomic absorption spectrophotometer. Several indices were calculated to estimate the contamination levels. The results indicated the following order of metal concentrations: Fe > Sr > Mn > Zn > Ni > Pb > Cu > Co > Cd, and revealed that the investigated sediments are highly enriched and contaminated with Sr, Cd, Pb and Zn. Statistical analyses subdivided the elements into Fe and Mn from natural sources, Sr, Cd, Pb and Zn from anthropogenic sources, and Ni, Cu and Co from combined natural and anthropogenic sources. The average Pb and Cd concentrations are considerably higher compared to the Caspian Sea, Indian Ocean, northern Red Sea, background shale, and continental crust. Possible sources of pollutants are fishing operations, antifouling paints, runoff, desalination plants, industries and dissolution of carbonate sediments.