Increase In Ni Concentrations Research Articles

Pistia Stratiotes based heavy metals phytoremediation of a Himalayan river impacted by hydroelectric plant in an Indo Burma hotspot region

ABSTRACT Present study attempts to study the impact of Serlui-B hydroelectric dam on water quality (‘water-energy nexus’) of a Himalayan river and to devise possible phytotechnology for heavy metals remediation. Physico-chemical characteristics of water were analyzed using ‘American Public Health Association (APHA)’ methods while Atomic Absorption Spectrophotometer (AAS) was used for estimation of heavy metals. To this end, concentrations of Fe and Ni were recorded above permissible limit which can impose public health risks. Therefore, phytoremediation experiments were performed by using Pistia stratiotes L. (water lettuce) and effects of Fe and Ni concentrations (1.0, 2.0, and 5.0 mg/L) on photosynthetic pigments were observed. Phytoremediation investigations using 24 aquaria (of 40.5 L) revealed that P. stratiotes was an effective hyperaccumulator of Fe and Ni with maximum removal efficiency of 96.2% and 92%, respectively. In relation to bioaccumulation indices, the bioconcentration factor (BCF) values decreased with increase in Fe and Ni concentrations, whereas the translocation factor (TF) was noted higher at low concentrations and vice versa. Furthermore, the total chlorophyll content and carotenoid levels in P. stratiotes demonstrated negative significant correlation with the rise in Fe/Ni concentrations that may be considered as an adaptive biochemical strategy to mitigate metals induced oxidative stress. The present study can further be extrapolated to field phytoremediation for ameliorating both physico-chemical and metallic contaminants. Last, the role of microbial biodiversity associated with P. stratiotes should be elucidated in future to help achieve SDG 6 and environmental sustainability.

Olivine avoidance behaviour by marine gastropods (Littorina littorea L.) and amphipods (Gammarus locusta L.) within the context of ocean alkalinity enhancement

Gigaton scale atmospheric carbon dioxide (CO2) removal (CDR) is needed to keep global warming below 1.5 °C. Coastal enhanced olivine weathering is a CDR technique that could be implemented in coastal management programmes, but its CO2 sequestration potential and environmental safety remain uncertain. Large scale olivine spreading would change the surficial sediment characteristics, which could potentially reduce habitat suitability and ultimately result in community composition changes. To test this hypothesis, we investigated the avoidance response of the marine gastropod Littorina littorea (Linnaeus, 1758) and marine amphipod Gammarus locusta (Linnaeus, 1758) to relatively coarse (83 – 332 µm) olivine and olivine-sediment mixtures during short-term choice experiments. Pure olivine was significantly avoided by both species, while no significant avoidance was observed for sediment with 3% or 30% w/w olivine. For L. littorea, aversion of the light green colour of pure olivine (i.e. positive scototaxis) was the main reason for avoidance. Moreover, olivine was not significantly avoided when it was 7.5 cm (45%) closer to a food source/darker microhabitat (Ulva sp.) compared to natural sediment. It is inferred that the amphipod G. locusta avoided pure olivine to reduce Ni and Cr exposure. Yet, a significant increase in whole body Ni concentrations was observed after 79 h of exposure in the 30% and 100% w/w olivine treatments compared to the sediment control, likely as a result of waterborne Ni uptake. Overall, our results are significant for ecological risk assessment of coastal enhanced olivine weathering as they show that L. littorea and G. locusta will not avoid sediments with up to 30% w/w relatively coarse olivine added and that the degree of olivine avoidance is dependent on local environmental factors (e.g. food or shelter availability).

Morphological and Structural Responses of Albizia lebbeck to Different Lead and Nickel Stress Levels

Lead (Pb) and nickel (Ni) are serious soil pollutants that adversely affect plant growth and development and need to be removed through phytoremediation. The present study aimed to assess the morphological indices of Albizia lebbeck (L.) (Benth.) in relation to anatomical modifications for survival under both Pb and Ni stress. The seedlings of A. lebbeck were established and then subjected to four different concentrations, viz. 0 mM, 25 mM, 50 mM and 75 mM, of Pb and Ni for 14 days in two phases. Morphological traits such as shoot length (70.93%), fresh weight (79.27%), dry weight (83.9%), number of root hairs (65.7%), number of leaves per plant (67.4%) and number of leaflets per plant greatly reduced under Pb or Ni stress. Surprisingly, root length increased rather than decreased with the increase in Pb or Ni concentrations, along with an increase in leaflet width, leaflet length and leaflet area. Moreover, root cortical cell area, metaxylem area and phloem area decreased at 75 mM of Pb and Ni while epidermal thickness and cell area increased. Stem epidermal thickness, cell area and phloem area significantly decreased with the consistent increase in metaxylem area and cortical region thickness under both Pb and Ni stress. Leaf anatomical traits such as midrib thickness, abaxial epidermal thickness and stomatal density and adaxial epidermal thickness and stomatal area significantly increased with increasing Pb or Ni stress. Correlation analysis revealed close relations among morphological and anatomical traits (such as root length with cortical region thickness) for better plant survival under Pb or Ni stress, and a PCA-biplot further verified these correlation analyses. Cluster analyses demonstrated the associations among the morphological and anatomical traits based on different stress levels. Furthermore, we found that the longer exposure (from phase 1 to phase 2) of heavy metals stress is more dangerous for plant survival and can ultimately lead to plant death. Moreover, our results also confirmed that Ni is more harmful or dangerous to plants than Pb at high and moderate concentrations. The anatomical modifications ensured the survival of A. lebbeck in extreme heavy metals stress and therefore unlocked its potential to be used as a natural source of phytoremediation. We also recommend that the genetic potential of A. lebbeck associated with its survival under heavy metal stress be investigated.

Iron limitation effect on H2/CO2 biomethanation: Experimental and model analysis

Trace metals are indispensable for the metalloenzymes involved for efficient H2/CO2 biomethanation. In-depth understanding of trace metals requirements of methanogens cannot only lead to robust and stable operation, but also can enhance CH4 productivity. In this study, the effect of Fe, Mn, Co, Ni, Cu, Zn, Se, Mo and W on the H2/CO2 biomethanation was examined. In a period of nutrient deprivation, suppression of hydrogenotrophic archaea was revealed at higher feed gas rates, leading to a significant drop in CH4 content and a concomitant rise in acetic acid concentration. After nutrient supplementation, the increase in Co, Ni and Fe concentrations were pivotal factors for enhanced methanogenic activity, leading to a CH4 content of more than 98% in the outlet biogas and a sharp drop in acetic acid concentration. Moreover, mathematical modeling was employed to simulate the influence of the most prominent element, iron, on the biomethanation process. The amended BioModel demonstrated that Fe limitation suppresses hydrogenotrophic archaea which consequently leads to H2 accumulation and growth of homoacetogenic bacteria.

Development history and composition of peatland in the Numto natural park in Western Siberia, Russia

A flat frost mound bog in the Numto Natural Park located in the northern taiga of Western Siberia (Khanty-Mansi Autonomous Okrug) was studied. Radiocarbon dating showed that the peatland formation began about 6658 cal years BP. Peat accumulation was slow due to the permafrost influence. The peat accumulation rate had the highest value of 0.3 mm/year between 5500 and 3400 cal years BP, then it sharply decreased to 0.1 mm/year due to climate cooling and remained at that level up to day. The change from cotton grass to sphagnum peat, which indicated transition to the oligotrophic stage of peatland development, was dated around 1800 cal years BP. The chemical composition of peat was characterized by the increase in Cu, Ni, Zn, Mn, Li, Ti and Mo concentrations with depth. The peak of Pb concentration in the upper horizon was likely to result from the former technogenic impact. Concentrations of microelements in the studied peat core were generally comparable to those in peatlands in the south-east of Western Siberia, except for the high concentration of Zn that was connected with the predominance of cotton grass in the major part of the studied core.

Responses of growth and antioxidative enzymes to different Ni concentrations in castor bean (Ricinus communis)

A pot culture experiment was conducted to investigate the effect of different levels of nickel on growth and biochemical parameters of castor bean (Ricinus communis L.). Castor seedlings were grown in control conditions or in soil amended with 50, 100, 300 and 500 mg kg‑1 of Ni. Plants were harvested after 60 days of sowing. A significant decrease in growth, and concentration of chlorophyll and carotenoids were observed with increasing concentrations of Ni. Leaf proline and malondialdehyde concentration increased considerably in response to Ni application. It was observed that the protein concentration in the leaves of castor plants decreased significantly with the increase in Ni concentrations in soil. An increase in protein content and enzyme activities was observed at increasing Ni concentration in soil. Significant changes in the antioxidative enzyme activities were observed in R. communis treated with varying Ni doses. It was found that with increasing concentrations of Ni in soil, the activity of the enzymes also increased. This suggests that the increase of enzyme activity due to Ni toxicity might play a role in the defence response of R. communis.

Performance evaluation and microbial community shift of sequencing batch reactors under different nickel (Ni(II)) concentrations

Abstract The performance, microbial enzymatic activities and the microbial community shift of sequencing batch reactors (SBRs) were evaluated under long-term exposure to 0–30 mg/L nickel (Ni(II)). More than 5 mg/L Ni(II) showed evident inhibition on NH 4 + -N removal, whereas Ni(II) at 30 mg/L decreased the COD removals of SBRs. The presence of 2 mg/L Ni(II) showed a slight promotion on the microbial nitrifying rates, denitrifying rates and the corresponding enzyme activities, whereas 5–30 mg/L Ni(II) reduced the pollutants removal rates and key enzymatic activity. The inhibition of Ni(II) on the above-mentioned microbial activities gradually increased with an increase in operational time and influent Ni(II) concentrations owing to the continual accumulation of Ni(II) contents in sludge flocs. High Ni(II) concentrations at 5–30 mg/L induced the microbial cellular to produce a higher reactive oxygen species and lactate dehydrogenase level. The microbial diversity and richness gradually declined with an increase in Ni(II) concentrations. The relative abundance of Nitrosomonas, Nitrospira and identified denitrifying bacteria displayed some changes under different Ni(II) concentrations.

Natural and anthropogenic sources of lead, zinc, and nickel in sediments of Lake Izabal, Guatemala

Sediments in Lake Izabal, Guatemala, contain substantial lead (Pb), zinc (Zn), and nickel (Ni). The lack of historical data for heavy metal concentrations in the sediments makes it difficult to determine the sources or evaluate whether inputs of metals to the lake have changed through time. We measured the relative abundances and concentrations of Pb, Zn, and Ni by X-Ray Fluorescence core scanning and by Inductively Coupled Plasma Optical Emission Spectrometry in three sediment cores to explore stratigraphic distributions of metals in the lake deposits. High amounts of Pb and Zn in the core taken near the Polochic Delta suggest that galena and sphalerite mining increased Pb and Zn delivery to Lake Izabal between ~1945 and 1965 CE. An up-core Ni increase in the core taken near a different mine on the north shore of Lake Izabal suggests that recent nickel mining operations led to an increase in Ni concentrations in the local sediments, but amounts in the other cores indicate that Ni is not widely distributed throughout the lake. Sediment cores from Lake Izabal are reliable recorders of heavy metal input to the lake, and were measured to establish background metal levels, which would otherwise be unavailable. Concentrations of Pb, Zn, and Ni in older, pre-20th-century Lake Izabal sediments reflect input from natural erosion of bedrock. Our results provide previously unavailable estimates of background metal concentrations in Lake Izabal before the onset of mining. These results are necessary for future monitoring related to mining contamination of the lake ecosystem.

The Specific Features of the Microcomponent Composition of Pore Solutions in the Rocks of the Bazhenov Formation, Western Siberia

The results of experimental studies of the macrocomponent and microcomponent compositions of pore solutions in the bituminous siliceous shales of the Bazhenov Formation (BF) in Western Siberia with total organic carbon (TOC) contents up to 12.63% (“normal rocks”) and the silty sandstones of the “anomalous” section of the BF with TOC contents no higher than 0.63% (“anomalous” rocks) are presented. The studies of water extracts from core samples were performed. It was found that the pore solutions in the rocks of the “normal” BF rocks are sodium sulfate–bicarbonate, whereas the solutions in the “anomalous” rocks are sodium bicarbonate–chloride. The following tendencies were noted in the pore solutions of both “normal” and “anomalous” rocks compared with the oceanic water: (a) increase in Mn, Co, Ni, Cu, Zn, Mo, Sb, Cd, Ba, V, and Cr concentrations to varying degrees; (b) elevated Cs, Pb, and Ti concentrations in pore solutions of “anomalous” rocks only; (c) reduced Li, B, Rb, and Sr concentrations. A direct correlation between Li, B, Ba, Sr, U, Mo, Cd, Sb, and Ni concentrations in the pore water and total organic carbon (TOC) contents in the rocks was established. The concentrations of V, Cs, Sb, Rb, Ti, and Mn in pore waters display a close to inverse correlation with TOC content in rocks. The content of Ba in the pore solutions of the “normal” BF rocks equals or exceeds the Sr content, which is abnormal compared with formation water in most oil fields and with ocean water and is attributable to the specific features of organic-rich mudstone accumulation, considering that the Sr content in the “anomalous” rocks of the BF is two times higher than the Ba content, which is closer to their usual ratios in most natural waters.

Concentration of Heavy Metals in Soils under Cemetery Occupation in Amazonas, Brazil

ABSTRACT The study aimed to quantify Cd, Cr, Cu, Ni, Pb, Zn, Al, Fe, and Mn concentrations in soils due to cemetery occupation in the Brazilian Amazon in order to assess the potential of environmental contamination. Atotal of 45 samples were collected in the 0.00–0.40, 0.40–0.80, and 0.80–1.20m layers, with trenches opened in a Gleysol (Cemetery - I) and Cambisol (Cemetery - II) to determine Fe, Al, Mn, Cr, Cu, Cd, Ni, Pb, and Zn contents. Chemical and particle size analyses were also performed. Soil sample digestion was based on the EPA 3051A method and metal concentrations were determined by ICP-OES. The results were submitted to descriptive statistics, control charts, and multivariate statistics by principal components. The effective increase in Fe, Cr, Cu, Ni, Pb, and Zn concentrations indicates ahigher potential of contamination by these metals due to cemetery activity, with concentrations above the recommended reference values for Brazilian Amazon sediment soils. Soil shows ability to return, resilience, to the chemical quality and natural concentrations of potentially toxic elements with the inactivation of cemetery activities. The clay fraction and organic matter are the main coordinators of metal dynamics in soil profiles.

Effect of Nickel Supplementation on Liver and Kidney Function Test and Protein Metabolism in Growing Cattle

This study was conducted to assess the nickel (Ni) content of commonly available feedstuffs and their supplemental effect on biomarkers of liver and kidney function and protein metabolism in growing cattle. Eighteen growing Hariana heifers were randomly assigned to three groups for 90 days and managed on similar feeding regimen except that these three groups were supplemented with 0.0 (Ni0.0), 1.5 (Ni1.5), and 3.0 (Ni3.0) of Ni/kg DMI. Cereal grain by-products, cakes and meals, green fodders, molasses, and compounded concentrate were high in Ni content. Cereal grains, straw, and stovers were moderate to low in Ni content. Dietary supplementation of 3.0 mg of Ni/kg DMI showed linear increase (P < 0.01) in average daily gain. No effects of treatments were observed on haemoglobin concentration, haematocrit value, aspartate aminotransferase level, alanine aminotransferase level, and alkaline phosphatase level. Circulating levels of bilirubin (P < 0.05) and creatinine (P < 0.01) showed dose-dependent increase with supplemental Ni. Heifers receiving diet supplemented with Ni showed higher (P < 0.001) plasma urease activity, plasma levels of total protein, albumin, globulin, and plasma urea nitrogen as compared to non-supplemented heifers. Ni supplementation showed a trend of linear increase (P < 0.001) in plasma Ni concentrations, and Ni level was observed highest in Ni3.0 group. Mean plasma iron (Fe) concentration showed no effect of Ni supplementation. The results of the present study indicate that Ni supplementation seems to improve performance in growing cattle by modulating urease activity and protein metabolism.

Effects of Nickel Supplementation on Antioxidant Status, Immune Characteristics, and Energy and Lipid Metabolism in Growing Cattle.

Nickel (Ni) has not been elucidated as an essential mineral in dairy animals, though in plants and lower organisms, its role in activation of urease enzyme is well known. This study was conducted to evaluate the effect of Ni supplementation on intake, growth performance, urease activity, antioxidant and immune status, and energy and lipid metabolism in growing cattle. Eighteen growing Hariana heifers were randomly allocated into three groups on body weight (125 ± 3.0kg) and age basis (10 ± 2.0months). Feeding regimen was similar in all the groups except that treatment groups were supplemented with 0.0 (Ni0.0), 1.5 (Ni1.5), and 3.0 (Ni3.0) mg of Ni/kg dry matter (DM) in three respective groups. DM intake (DMI), average daily gain (ADG), feed efficiency, plasma urease activity, biomarkers of antioxidant and immune status, energy and lipid metabolism, and plasma Ni levels were observed during the 90-day experimental period. There was linear increase (p< 0.05) in mean DMI and ADG without affecting feed efficiency was observed in 3.0mg of Ni/kg DM supplemented heifers. Dietary Ni supplementation showed linear increase (p < 0.05) in mean plasma urease activity. No effects of (p > 0.05) of Ni supplementation were observed on superoxide dismutase (SOD) and catalase (CAT) activity and plasma lipid peroxide (LPO) concentration; whereas, mean plasma total antioxidant status (TAS) showed linear decrease (p < 0.001) in Ni-supplemented groups. Adding Ni up to 3.0mg of Ni/kg DM did not exert (p > 0.05) any effect on plasma total immunoglobulin and immunoglobulin G (IgG) concentrations. Mean plasma cortisol level showed negative association with supplemental Ni levels and concentration was found lowest (p < 0.05) in 3.0mg of Ni/kg DM-added group. Dietary Ni supplementation did not affect mean plasma concentrations of glucose, cholesterol, triglyceride, and non-esterified fatty acids (NEFA). There was a linear increase (p< 0.001) in plasma Ni concentrations as the Ni concentrations increased in the diet. The results of present study indicated that dietary supplementation of 3.0mg of Ni/kg DM improved performance of growing cattle by increasing urease activity.

Quantitative source identification and risk assessment of trace elements in soils from Leizhou Peninsula, South China

ABSTRACTDifferentiating contribution of natural sources and anthropogenic inputs to soil element concentrations can provide important basis for pollution and risk assessments. Fifty-five surface soil samples were collected from farmland (n = 33) and forest land (n = 22) in the Leizhou Peninsula for the measurement of trace elements (Cr, Co, Ni, Cu, Zn, As, Pb, and Cd) concentrations. It was found that soil Cr, Ni, Cu, Zn and Cd concentrations were significantly higher in farmland soils than in forest soils (p < 0.05). Industrial discharges accounted for the increase in Cr, Co, Ni, and Cu concentrations with mean contribution rates of 10.9%, 29.4%, 23.2%, and 25.3%, whereas agricultural activities contributed significantly (14.6%−92.4%) to soil Cd levels. The pollution levels of individual element based on a geo-accumulation index, and enrichment and contamination factors roughly followed a decreasing order of Cd > Co ≈ Cu ≈ Ni ≈ Cr > Zn ≈ As ≈ Pb. Severe contamination was found near industrial areas, which resulted in a moderate or considerable ecological risk. Soil Cr mainly derived from weathering process of basaltic rocks and industrial sources resulted in non-carcinogenic hazard and carcinogenic risk indices up to 2.47 and 2.79 × 10–4, respectively, near industrial areas, leading to that children suffered more from higher non-carcinogenic and carcinogenic risks than adults.

The accumulating ability and nickel tolerance of Brassicaceae species of the North Caucasus in connection with the problem of phytoremediation

In model experiments in sand culture the wildgrowing species of fam. Brassicaceae flora of the North Caucasus: Alyssum murale Walds. et Kit., A. alyssoides (L.) L., A. campestre (L.) L., Erysimum ibericum (Adam.) DC. were studied for the effects of high concentrations of Ni (1 and 2mM) on storage capacity and sustainability indicators: biomass accumulation, the level of photosynthetic pigments, the balance of mineral elements. The experimental variants show a different degree of increase in Ni concentrations in compared species, the maximum - in hyperaccumulator A. murale. On the basis of variability of sustainability indicators we compiled a sequence of species tolerances to Ni: A. murale>E. ibericum>A. campestre>A. alyssoides. Species E. ibericum can be used for phytostabilization of Ni contaminated areas and species A. murale and A. campestre - for phytoextraction of nickel from soils.

Material and elemental composition of surface aerosols on the north-western coast of the Kandalaksha Bay of the White Sea

Continuous sampling of aerosols is carried out on the north-western (NW) coast of the Kandalaksha Bay of the White Sea. Aerosol matter from 30 filters collected in summer and autumn, 2013, and spring, 2014, was studied by scanning electron microscopy. The elemental composition of aerosol matter was determined by the inductively-coupled plasma mass-spectrometry (ICP-MS). The major portion of aerosol particles collected in summer is of biogenic origin. Heavy metal concentrations in aerosols are at the Arctic background level. The distribution of trace element concentrations is characterized by simultaneous peaks of different elements. The backward trajectory analysis shows an increase in Ni and Cu concentrations corresponding to the arrival of air masses from the western part of the Kola Peninsula. That suggests the influence of smelters.

Ni-inhibited seedling growth in Zea mays (maize) involves alterations in associated biochemical processes

An experiment was carried out to investigate the effect of Nickel (Ni) (5–50 µM) on seedling growth, dry weight, chlorophyll content and carotenoid content of Zea mays (maize) grown in petries after 96 h exposure to Ni. The experiment was further extended to investigate the effect of Ni on water soluble protein content and the activities of protease and oxidoreductase enzymes (POD, PPO) in the roots of maize exposed to Ni. The results indicated that Ni inhibits both root and coleoptile length in test plant followed by reduction in chlorophyll and carotenoid contents. Decrease in the activity of proteases and protein content was also observed in test plant. The reduction was observed more in Z. mays roots as compared to coleoptile when treated with Ni. Further, significant reduction in chl b was noted more than chl a in the test plant. However, the increased activities of peroxidase (POD) and polyphenol oxidase (PPO) were observed with increase in Ni concentrations in Z. mays roots.

Effects of sewage sludge fertilizer on heavy metal accumulation and consequent responses of sunflower (Helianthus annuus).

Use of sewage sludge, a biological residue produced from sewage treatment processes in agriculture, is an alternative disposal technique of waste. To study the usefulness of sewage sludge amendment for Helianthus annuus, a pot experiment was conducted by mixing sewage sludge at 2.5, 5, and 7.5% (w/w) amendment ratios to the agricultural soil. Soil pH decreased whereas electrical conductivity, organic matter, total N, available P, and exchangeable Na, K, and Ca increased in soil amended with sewage sludge in comparison to unamended soil. Sewage sludge amendment led to significant increase in Pb, Ni, Cu, Cr, and Zn concentrations of soil. The increased concentration of heavy metals in soil due to sewage sludge amendment led to increases in shoot and root concentrations of Cr, Cu, Ni, and Zn in plant as compared to those grown on unamended soil. Accumulation was more in roots than shoots for most of the heavy metals. Moreover, high metal removal for the harvestable parts of the crops was recorded. Sewage sludge amendment increased root and shoot length, leaves number, biomass, and antioxidant activities of sunflower. Significant increases in the activities of antioxidant enzymes and in the glutathione, proline, and soluble sugar content in response to amendment with sewage sludge may be defense mechanisms induced in response to heavy metal stress. Graphical abstract Origin, fate and behavior of sewage sludge fertilizer.

Efficient removal of arsenic, antimony and nickel from mine wastewaters in Northern treatment peatlands and potential risks in their long-term use

The number of metal mines, the amount of ore processed, and thus the amount of mine wastewaters have been rapidly increasing in recent decades. Pretreated process effluent and drainage waters containing high concentrations of e.g., arsenic (As), antimony (Sb), and nickel (Ni) have been purified for up to 6 years in treatment peatlands at a gold mine in Finnish Lappland prior to their release into downstream water bodies. Retention efficiencies based on monitoring of peatland inflow and outflow waters indicated that retention of As, Sb, and Ni was generally good (up to 95%) but temporarily variable. Other contaminants such as sulfate or iron were retained less efficiently or were even leaching from the peatland. Most of the As, Sb, and Ni was retained close to the wastewater distribution ditch, and there was a near-linear increase in As, Sb, and Ni concentrations in the peatlands over time. Adsorption experiments indicated the high potential of peat soils to adsorb As, Ni and especially Sb. Accumulation of contaminants has led to or will lead to concentrations exceeding higher guideline values for contaminated soils within the next 1–18 years, which indicates a limited lifetime for treatment peatlands. Leaching of contaminants is anticipated in situations where clean natural waters mix with mine waters, e.g., during snowmelt or after mine closure, and desorption experiments suggest that especially easily mobilized (i.e., loosely-bound) fractions of As, Sb, and Ni are likely to leach from the treatment peatlands. The collective data indicate (i) high purification efficiencies for As, Sb, and Ni in the peatlands, (ii) high adsorptive capacity of the peat soil for those contaminants, (iii) increased risk of contaminant leaching e.g., after mine closure, and (iv) a need for further studies of environmental parameters and retention processes affecting contaminant removal efficiencies and potential lifetimes of treatment peatlands.

Evidence that the Deepwater Horizon Oil Spill Caused a Change in the Nickel, Chromium, and Lead Average Seasonal Concentrations Occurring in Sea Bottom Sediment Collected from the Eastern Gulf of Mexico Continental Shelf Between the Years 2009 and 2011

Preliminary analysis indicates a change with time in nickel (Ni), chromium (Cr), and lead (Pb) concentrations in sea bottom sediment samples which were collected during the falls of 2009, 2010, and 2011 along the continental shelf of the Eastern Gulf of Mexico. These samples bracket the Deepwater Horizon Oil Spill which occurred during the spring and summer of 2010. The sea bottom samples were collected as part of the recurring NOAA small pelagics survey of the continental shelf from Texas to Florida. A Shipek grab sampler was used to retrieve 37 sediment samples from the upper 15 cm of the sea bottom for analysis from the carbonate platform off of the west coast of Florida and relict sand off of the coast of Alabama. The samples were analyzed for six trace metals, Ni, Cr, Pb, vanadium (V), thallium (Tl), and mercury (Hg). The silt/clay fraction of the sediment had the highest adsorption affinity for Ni, Pb, and Tl metals relative to V, Cr, and Hg. A comparative analysis of the trace metal concentrations indicates that there is a statistically significant (at p < 0.05 or p < 0.01) increase in Ni, Cr, and Pb concentrations in sea bottom sediment 3 months after the oil spill. One year later, however, the 2011 samples indicate that Ni, Cr, and Pb significantly decreased (at p < 0.05 or p < 0.01) in comparison to 2010. Vanadium did not statistically change from 2009 to 2011. Crude oil is known to contain V and Ni, and the V–Ni ratio (V/V+Ni) has been used as a fingerprint for the Macondo crude oil source. The V–Ni ratios for the sediment sampling years 2009, 2010, and 2011 were 0.52, 0.46, and 0.57, respectively. In this study, approximately 1 year and 3 months after the oil spill, there is evidence, such as the V–Ni ratio, that trace metal concentrations in sea bottom sediment are approaching pre-spill levels. We conclude these differences in Ni concentrations, and the V–Ni ratios are an effective means of monitoring the impact of an oil spill and the use of dispersants to alleviate the spill impact.

Effects of Municipal Sewage Sludge Doses on the Chlorophyll Contents and Heavy Metal Concentration of Sugar Beet (Beta vulgaris var. saccharifera)

ABSTRACT The present study was conducted to assess the suitability of sewage sludge amendment (SSA) in soil for Beta vulgaris var. saccharifera (sugar beet) by evaluating the heavy metal accumulation and physiological responses of plants grown at a 10%, 25%, and 50% sewage sludge amendment rate. The sewage sludge amendment was modified by the physicochemical properties of soil, thus increasing the availability of heavy metals in the soil and consequently increasing accumulation in plant parts. Cd, Pb, Ni, and Cu concentrations in roots were significantly higher in plants grown at 25% as compared to 50% SSA; however, Cr and Zn concentration was higher at 50% than 25% SSA. The concentrations of heavy metal showed a trend of Zn > Ni > Cu > Cr > Pb > Cd in roots and Zn > Cu > Ni > Cr > Pb > Cd in leaves. The only instance in which the chlorophyll content did not increase after the sewage sludge treatments was 50%. There were approximately 1.12-fold differences between the control and 50% sewage sludge application for chlorophyll content. The sewage sludge amendment led to a significant increase in Pb, Cr, Cd, Cu, Zn, and Ni concentrations of the soil. The heavy metal accumulation in the soil after the treatments did not exceed the limits for the land application of sewage sludge recommended by the US Environmental Protection Agency (US EPA). The increased concentration of heavy metals in the soil due to the sewage sludge amendment led to increases in heavy metal uptake and the leaf and root concentrations of Ni, Zn, Cd, Cu, Cr, Pb, and Zn in plants as compared to those grown on unamended soil. More accumulation occurred in roots and leaves than in shoots for most of the heavy metals. The concentrations of Cd, Cr, and Pb were more than the permissible limits of national standards in the edible portion of sugar beet grown on different sewage sludge amendment ratios. The study concludes that the sewage sludge amendment in the soil for growing sugar beet may not be a good option due to risk of contamination of Cr, Pb, and Cd.