Showing papers on "Soil contamination published in 2011"

A Review on Heavy Metals (As, Pb, and Hg) Uptake by Plants through Phytoremediation

Abstract: Heavy metals are among the most important sorts of contaminant in the environment. Several methods already used to clean up the environment from these kinds of contaminants, but most of them are costly and difficult to get optimum results. Currently, phytoremediation is an effective and affordable technological solution used to extract or remove inactive metals and metal pollutants from contaminated soil and water. This technology is environmental friendly and potentially cost effective. This paper aims to compile some information about heavy metals of arsenic, lead, and mercury (As, Pb, and Hg) sources, effects and their treatment. It also reviews deeply about phytoremediation technology, including the heavy metal uptake mechanisms and several research studies associated about the topics. Additionally, it describes several sources and the effects of As, Pb, and Hg on the environment, the advantages of this kind of technology for reducing them, and also heavy metal uptake mechanisms in phytoremediation technology as well as the factors affecting the uptake mechanisms. Some recommended plants which are commonly used in phytoremediation and their capability to reduce the contaminant are also reported.

Evidence for negative effects of TiO2 and ZnO nanoparticles on soil bacterial communities.

Abstract: Increased use of engineered nanoparticles (ENPs) raises concerns about their environmental impacts, but the effects of metal oxide ENPs on environmental processes and the organisms that carry them out remain largely unknown. This study evaluated the impacts of TiO2 and ZnO ENPs on soil bacterial communities. Soils collected from a California grassland were exposed to different doses of nanoparticulate TiO2 (0, 0.5, 1.0, and 2.0 mg g−1 soil) and ZnO (0.05, 0.1, and 0.5 mg g−1 soil) in microcosms over 60 days. The effects on soil microbial biomass were assessed by substrate induced respiration (SIR) and total extractable soil DNA. The effects on bacterial community composition were evaluated by terminal restriction fragment length polymorphism (T-RFLP) analysis. Total soil respiration indicated impacts on overall microbial activity. We found that both nano-TiO2 and nano-ZnO reduced both microbial biomass (as indicated by declines in both SIR and DNA) and diversity (by T-RFLP). Both types of nanoparticles al...

The Red Mud Accident in Ajka (Hungary): Plant Toxicity and Trace Metal Bioavailability in Red Mud Contaminated Soil

Abstract: The red mud accident of October 4, 2010, in Ajka (Hungary) contaminated a vast area with caustic, saline red mud (pH 12) that contains several toxic trace metals above soil limits. Red mud was characterized and its toxicity for plants was measured to evaluate the soil contamination risks. Red mud radioactivity (e.g., 238U) is about 10-fold above soil background and previous assessments revealed that radiation risk is limited to indoor radon. The plant toxicity and trace metal availability was tested with mixtures of this red mud and a local noncontaminated soil up to a 16% dry weight fraction. Increasing red mud applications increased soil pH to maximally 8.3 and soil solution EC to 12 dS m−1. Shoot yield of barley seedlings was affected by 25% at 5% red mud in soil and above. Red mud increased shoot Cu, Cr, Fe, and Ni concentrations; however, none of these exceed toxic limits reported elsewhere. Moreover, NaOH amended reference treatments showed similar yield reductions and similar changes in shoot compo...

Eco-toxicity of petroleum hydrocarbon contaminated soil.

Abstract: Total petroleum hydrocarbons (TPH) contaminated soil samples were collected from Shengli Oilfield of China. Toxicity analysis was carried out based on earthworm acute toxicity, plant growth experiment and luminescent bacteria test. The soil was contaminated by-petroleum hydrogcarbons with TPH concentration of 10.57%. With lethal and sub-lethal rate as endpoint, earthworm test showed that the LD50 (lethal dose 50%) values in 4 and 7 days were 1.45% and 1.37% respectively, and the inhibition rate of earthworm body weight increased with higher oil concentration. TPH pollution in the soil inhibited seed germination in both wheat and maize experiment when the concentration of petroleum was higher than 0.1%. The EC50 (effective concentration 50%) for germination is 3.04% and 2.86% in maize and wheat, respectively. While lower value of EC50 for root elongation was to be 1.11% and 1.64% in maize and wheat, respectively, suggesting higher sensitivity of root elongation on petroleum contamination in the soil. The EC50 value in luminescent bacteria test was 0.47% for petroleum in the contaminated soil. From the experiment result, it was concluded that TPH content of 1.5% is considered to be a critical value for plant growth and living of earthworm and 0.5% will affect the activity of luminescent bacteria.

Organic matter-solid phase interactions are critical for predicting arsenic release and plant uptake in Bangladesh paddy soils.

Abstract: Agroecological zones within Bangladesh with low levels of arsenic in groundwater and soils produce rice that is high in arsenic with respect to other producing regions of the globe Little is known about arsenic cycling in these soils and the labile fractions relevant for plant uptake when flooded Soil porewater dynamics of field soils (n = 39) were recreated under standardized laboratory conditions to investigate the mobility and interplay of arsenic, Fe, Si, C, and other elements, in relation to rice grain element composition, using the dynamic sampling technique diffusive gradients in thin films (DGT) Based on a simple model using only labile DGT measured arsenic and dissolved organic carbon (DOC), concentrations of arsenic in Aman (Monsoon season) rice grain were predicted reliably DOC was the strongest determinant of arsenic solid-solution phase partitioning, while arsenic release to the soil porewater was shown to be decoupled from that of Fe This study demonstrates the dual importance of organic matter (OM), in terms of enhancing arsenic release from soils, while reducing bioavailability by sequestering arsenic in solution

Soils contaminated with explosives: Environmental fate and evaluation of state-of- the-art remediation processes (IUPAC Technical Report)*

Abstract: An explosion occurs when a large amount of energy is suddenly released. This energy may come from an over-pressurized steam boiler, from the products of a chemical reaction involving explosive materials, or from a nuclear reaction that is uncontrolled. In order for an explosion to occur, there must be a local accumulation of energy at the site of the explosion, which is suddenly released. This release of energy can be dissipated as blast waves, propulsion of debris, or by the emission of thermal and ionizing radiation. Modern explosives or energetic materials are nitrogen-containing organic compounds with the potential for self-oxidation to small gaseous molecules (N 2 , H 2 O, and CO 2 ). Explosives are classified as primary or secondary based on their susceptibility of initiation. Primary explosives are highly susceptible to initiation and are often used to ignite secondary explosives, such as TNT (2,4,6-trinitrotoluene), RDX (1,3,5-trinitroperhydro-1,3,5-triazine), HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazocane), and tetryl (N-methyl-N-2,4,6-tetranitro - aniline).

Ecophysiological and anatomical changes due to uptake and accumulation of heavy metal in Brachiaria decumbens

Abstract: The growth and developmental characteristics of grasses and their high biodiversity make such plants suitable for remediation of areas contaminated by heavy metals. Nevertheless, heavy metal toxic effect on the plants may cause alteration in their metabolic pathways, such as photosynthesis, respiration, and growth, modifying plant anatomy. This work aimed to evaluate the effect of levels of soil contamination (0, 7.5 % and 15 % m³ m-3) on biomass production, on photosynthetic characteristics and on anatomical changes in roots and leaves of brachiaria (Brachiaria decumbens Stapf.). After seeds were planted, seedlings were uprooted and replanted in vases containing soil at different contamination levels, being left to rest for 120 days. At the end of that time, plants presented reduced yield of root and shoot dry matter, contents of chlorophyll a, chlorophyll b, total chlorophyll and potential photosynthesis with increased of soil contamination. The cell layers of endodermis and exodermis in the root tissues and the cell walls of the xylem and cortical parenchyma all thickened as contamination increased. In the leaf tissues, the adaxial and abaxial epidermis presented increased thickness while the leaf blade presented reduced thickness as contamination increased with consequent change in the root growth rate. In general, the effects of heavy metal increased with the metal concentration. Some results indicate that B. decumbens seems to have some degree of heavy metal tolerance.

Heavy metal concentrations in groundwaters and soils of Thane Region of Maharashtra, India.

Abstract: Thane district is one of the most industrialized districts in Maharashtra. The heavy industrialization and the increasing urbanization are responsible for the rapidly increasing stress on the water and soil environment of the area. Therefore, an attempt has been made through comprehensive study on the groundwater contamination and soil contamination due to heavy metals in Thane region of Maharashtra. The area undertaken for the study was Thane and its suburbans Kalwa, Divajunction, Dombivali, Kalyan, and Ulhasnagar. Industrialization and urbanization lead to generation of large volumes of wastewater from domestic, commercial, industrial, and other sources, which discharged in to natural water bodies like river and creek in this region. Groundwater samples and soil samples were collected from residential, commercial, agriculture, and industrial areas. Groundwater samples were analyzed for various water quality parameters. The analytical data shows very high concentration of total dissolved solids, total hardness, total alkalinity, chemical oxygen demand, chloride etc. Groundwater and soil samples were analyzed for ten heavy metals by inductively coupled plasma (ICPE-9000) atomic emission spectroscopy. The analytical data reveal that, very high concentration level of arsenic, cadmium, mercury, and nickel throughout the industrial area. The random dumping of hazardous waste in the industrial area could be the main cause of the groundwater and soil contamination spreading by rainwater and wind. In the residential areas the local dumping is expected to be the main source for heavy metals. A comparison of the results of groundwater with WHO guidelines show that most of the groundwater sampling station are heavily contaminated with organic matter and heavy metals. Groundwater samples are heavily contaminated by arsenic, cadmium, mercury, and nickel. Similarly, the results of heavy metals in soil compared with Swedish soil guideline values for polluted soil show that soil samples collected from residential, commercial and industrial areas are heavily contaminated by arsenic, cadmium, mercury, and nickel.

Heavy Metal Concentration Survey in Soils and Plants of the Les Malines Mining District (Southern France): Implications for Soil Restoration

Abstract: Mining activities generate spoils and efflu- ents with extremely high metal concentrations of heavy metals that might have adverse effects on ecosystems and human health. Therefore, information on soil and plant metal concentrations is needed to assess the severity of the pollution and develop a strategy for soil reclamation such as phytoremedia- tion. Here, we studied soils and vegetation in three heavily contaminated sites with potential toxic metals and metalloids (Zn, Pb, Cd, As, TI) in the mining district of Les Malines in the Languedoc region (southern France). Extremely high concentrations were found at different places such as the Les Avinieres tailing basins (up to 160,000 mg kg -1 Zn, 90,000 mg kg -1 Pb, 9,700 mg kg -1 of As and 245 mg kg -1 of Tl) near a former furnace. Metal contamination extended several kilometres away from the mine sites probably because of the transport of toxic mining residues by wind and water. Spontaneous vegetation growing on the three mine sites was highly diversified and included 116 plant species. The vegetation cover consisted of species also found in non-contaminated soils, some of which have been shown to be metal- tolerant ecotypes (Festuca arvernensis, Koeleria vallesiana and Armeria arenaria) and several Zn, Cd and Tl hyperaccumulators such as Anthyllis vulneraria, Thlaspi caerulescens, Iberis intermedia and Silene latifolia. This latter species was highlighted as a new thallium hyperaccumulator, accumulating nearly 1,500 mg kg -1 . These species represent a patrimonial interest for their potential use for the phytoremediation of toxic metal-polluted areas.

Stabilization of Pb and Cd contaminated soils and soil quality improvements using waste oyster shells

Abstract: Large amounts of oyster shells are produced as a by-product of shellfish farming in coastal regions without beneficial use options. Accordingly, this study was conducted to evaluate the potential for the use of waste oyster shells (WOS) containing a high amount of CaCO3 to improve soil quality and to stabilize heavy metals in soil. To accomplish this, an incubation experiment was conducted to evaluate the ability of the addition of 1–5 wt% WOS to stabilize the Pb (total 1,246 mg/kg) and Cd (total 17 mg/kg) in a contaminated soil. The effectiveness of the WOS treatments was evaluated using various single extraction techniques. Soil amended with WOS was cured for 30 days complied with the Korean Standard Test method (0.1 M·HCl extraction). The Pb and Cd concentrations were less than the Korean warning and countermeasure standards following treatment with 5 wt% WOS. Moreover, the concentrations of Cd were greatly reduced in response to WOS treatment following extraction using 0.01 M·CaCl2, which is strongly associated with phytoavailability. Furthermore, the soil pH and exchangeable Ca increased significantly in response to WOS treatment. Taken together, the results of this study indicated that WOS amendments improved soil quality and stabilized Pb and Cd in contaminated soil. However, extraction with 0.43 M·CH3COOH revealed that remobilization of heavy metals can occur when the soil reaches an acidic condition.

Occurrence of PPCPs at a Wastewater Treatment Plant and in Soil and Groundwater at a Land Application Site

Abstract: Pharmaceuticals and personal care products (PPCPs) can reach soil and aquatic environments through land application of wastewater effluent and agricultural runoff. The objective of this research was to assess the fate of PPCPs at field scale. PPCPs were measured systematically in a wastewater treatment plant (WWTP), and in soil and groundwater receiving treated effluent from the WWTP. A land application site in West Texas was used as the study site; it has received treated wastewater effluent from the WWTP for more than 70 years in order to remove additional nutrients and irrigate non-edible crops. Target compounds (estrone, 17β-estradiol, estriol, 17α-ethynylestradiol, triclosan, caffeine, ibuprofen, and ciprofloxacin) in wastewater, sewage sludge, soil, and groundwater were determined using HPLC/UV with qualitative confirmatory analyses using GC/MS. Samples were collected quarterly over 12 months for wastewater and sludge samples and over 9 months for soil and groundwater samples. Results indicated that concentrations of PPCPs in wastewater influent, effluent, sludge solid phase, and sludge liquid phase were in the range of non-detected (ND)-183 μg/L, ND-83 μg/L, ND-19 μg/g, and ND-50 μg/L, respectively. Concentrations in soil and groundwater samples were in the range of ND-319 ng/g and ND-1,745 μg/L, respectively. GC/MS confirmation data were consistent with the results of HPLC/UV analyses. Overall, data indicate that PPCPs in the wastewater effluent from the WWTP transport both vertically and horizontally in the soil, and eventually reach groundwater following land application of the effluent.