Low Heavy Metal Research Articles

Leucine‐aminopeptidase activities in heavy‐metal contaminated soils from brownfields of Liberty State Park (583.6)

The brownfields of Liberty State Park served as rail yards for the Central New Jersey Terminal until the 1960s. These areas contain heavy metals such as Cd and Pb, which vary along a gradient. Previous research, such as the study done by Lee and Baek on a general shooting ranging in South Korea, has concluded that initial addition of heavy metals can inhibit enzymatic activities in soils. However, there was no known ongoing‐addition of heavy metals in our study sites since the closing of the rail station; concentrations of the heavy metals continued to persist in the soil for over the past 50 years. The purpose of this research is to determine the effect of persistent heavy metals concentrations on the activity of leucine‐aminopeptidase in the different brownfield sites at Liberty State Park. Fluometric analysis was used to determine the amount of the product amino‐7‐methylcoumarin (AMC) present in a given soil sample. The substrate analog leucine‐amino‐7‐methylcoumarin (LAMC) was added to the soil samples and enzymatic activities was determined by the amount of AMC produced over time. Interestingly, results showed an increase in the enzymatic activity of leucine‐aminopeptidase in the soil samples of the high heavy metal concentration sites compared to those of the lower heavy metal concentration sites

Concentration of heavy metals in the modern flood slackwater deposits along the upper Hanjiang River valley, China

Modern flood slackwater deposits (SWD) were systematically collected after the great flood events which occurred on 19 July, 2010 and on 19 September, 2011 along the upper Hanjiang River valley. Concentrations of heavy metals (Co, Cr, Cu, Ni, Pb, Zn, Ba, Mn and V) in the fresh flood SWD were determined. Enrichment Factor (EF) and Index of Geoaccumulation (Igeo) were employed for heavy metal assessment. These results show that Cu, Ni, Pb, Zn and Mn are defined as only minor enrichment and unpolluted in the upper Hanjiang River basin, whereas Co, Cr, Ba and V are defined as between moderate enrichment and moderately severe enrichment, and moderately polluted in the downstream of Ankang city. Principal component analysis (PCA) and correlation analysis confirm the results of EF and Igeo. Cluster analysis (CA) identifies that Ankang city is the boundary between higher and lower heavy metals in the modern flood SWD. Therefore, we can conclude that the source of Co, Cr, Ba and V is mainly from anthropogenic inputs, but the source of Cu, Ni, Pb, Zn and Mn is mixed from natural and anthropogenic inputs. Concentration of heavy metals in the downstream of Ankang city is higher than that in the upstream. These results would help to establish non-point sources of heavy metal pollution and provide important information for water conservation strategy during the great flood periods in the upper Hanjiang River basin.

Some Heavy Metals' Concentrations in the Metacarpal Bones of Paleontological Cattle from Azmashka Settlement Hill

The aim of the present study was to investigate and determine concentrations of some heavy metals in the cattle metacarpal bones, found from Azmashka settlement hill. They belonged to four periods: Early Neolith (EN), Early Halkolith (EH), Late Halkolith (LH) and Early Bronze (EB). The natural bone material was obtained from the archaeological site Azmashka village mound, found 6 km east of Stara Zagora (Bulgaria) and also from the territory of Hrishteni village, following radiocarbonic analysis. In the sampling an atomic absorption spectrophotometry was used. The samples have been burned dry and dissolved in acid until solution with optimal element concentration. Higher concentrations of iron (Fe), copper (Cu), zinc (Zn), manganese (Mn), lead (Pb), chrome (Cr) and magnesium (Mg) were observed. The quantity of Fe, Cu, Zn, Mn and Pb were with higher values at Early Halkolith, compared to the same in the other periods. The highest heavy metals’ concentrations were found, as following: iron, cooper, manganese, lead – at Early Halkolith and zink, chrome and magnesium – at Late Halkolith. The lowest heavy metals’ concentrations were found, as following: iron, manganese, chrome, magnesium – at Early Neolith and cooper, zink and lead– at Early Bronze. Differences in the other elements’ concentrations from the studied periods weren’t significant. Qualitative differences influenced by the heavy metals in the bone structure weren’t found. The content of heavy metals in the studied metacarpal bone material is considerably high compare to the normal values, mentioned by some researchers studied other species. The trend of concentration increasing is from Early Neolith to Early Bronze. This is due to the metacarpal bone contamination with soil, as which has been polluted from many years by the industrial manufacture of the nitrogen fertilizer.

Using Chlorella vulgaris to Decrease the Environmental Effect of Garbage Dump Leachates

Waste treatment in Phuket, Thailand produces two sources of leachate. The Landfill Leachate (LF) has low BOD (60-405 mg O2/L) and heavy metal levels are below legal limits. Garbage awaiting incineration, Garbage Pit Leachate (GPL), also produces a second leachate with a very high BOD (50-100 g O2/L) and NH3-N (763-2,045 mg/L). Zn and Cr exceed standards but Cu and Pb are low. Chlorella vulgaris was tested for its ability to decrease NH3-N, NO3--N, Total-P, BOD and COD and to remove and/or immobilize heavy metal at varying dilutions of leachate. The objectives of this study on Chlorella bioremediation were: 1) measure Chlorella growth in Landfill and Garbage Pit Leachate, 2) measure the effectiveness of Chlorella to decrease the physico-chemical parameters NH3- N, NO3-N, Total-P, BOD, COD 3) measure heavy metal removal from leachates. The minimum inoculum of Chlorella biomass which can grow in the LF was Chlorophyll a 0.259 μg/mL (A750=0.075). Chlorella significantly lowered its BOD and COD: Cr and Ni, already low in landfill leachate, were decreased by 70% and 66%. Chlorella grew well in LF diluted 30 % with tapwater: % removal of NH3-N (53.91%), BOD (52.78%) and COD (51.05%). The GPL was very toxic: only 10-20% dilutions of GPL were tolerated by Chlorella and cultures required continuous aeration by shaking to grow. The minimum necessary inoculum of Chlorella biomass in the GPL was Chlorophyll a=0.92 μg/mL (A750=0.19). In 20% dilution of GPL, Cr and Zn were decreased by 33% and 90% respectively to legal levels. % removal of NH3-N (41.5%), NO3--N (32.4%), Total-P (55.1%), BOD (49.2%) and COD (50.8%). Chlorella inoculations with a biomass of 1.17 μg/mL Chlorophyll a (A750=0.202) removed 90% of the Zn.

Factors influencing occurrence of a freshwater turtle in an urban landscape: a resilient species?

Context Species vary broadly in their ability to adapt to urbanisation. Freshwater turtles are vulnerable to the loss and degradation of terrestrial and aquatic habitat in urban environments. There have been few publications investigating impacts of urbanisation on freshwater turtles in Australia. Aims We investigated the effects of urbanisation on the distribution and abundance of the eastern long-necked turtle (Chelodina longicollis) in greater Melbourne. Methods We examined occurrence and relative abundance of C. longicollis at 55 wetlands across an urban–rural gradient in relation to site- and landscape-level factors. Occupancy was modelled using the program PRESENCE, and incorporated landscape and habitat covariates. A negative binomial regression model was used to examine the influence of landscape and habitat factors on relative abundance by using WinBUGS. Key results C. longicollis occupied 85% of the 55 wetlands we surveyed, and we found no evidence that wetland occupancy was influenced by the variables we measured. However, relative abundance was highest at wetlands with low water conductivity and heavy metal pollution, and in wetlands furthest from rivers. Conclusions C. longicollis appears to be resilient to urbanisation and is likely to persist in urban landscapes, possibly because of the creation of new wetlands in Australian cities. However, long-term studies focussed on demographic parameters, or survivorship, may elucidate as yet undetected effects of urbanisation. Although no specific management recommendations may be necessary for C. longicollis in urban areas at this time, this species may be in decline in non-urban areas as a result of climatic changes and wetland drying. Implications Our findings suggest that caution is required before drawing generalised conclusions on the impacts of urbanisation on turtles, as the effects are likely to be species-specific, dependent on specific ecology and life-history requirements. Further studies are required to ascertain these relationships for a wider array of species and over longer time spans.

Migration and Stabilization of Multiple Heavy Metals in an Aged Contaminated Soil under a Constant Voltage Electric Field

With the aim of metal decontamination, migration and stabilization of multiply heavy metals in an aged contaminated soil under a constant 1 V cm−1 parallel-plate electric field were investigated through monitoring the metal migration in the anolyte, as well as analyzing their species distribution residual in soil. Besides anionic Cr(VI), cationic metals were also found in the anolyte, primarily by the concentration-gradient-driven diffusion of free ions, especially when the produced H+ considerably increased their levels in the soil. After 295 h, parts of Cu, Cr, Ni, and Zn were found to electro-migrate into the intermediate area, but no obvious Pb migration was observed, likely ascribed to its own great inertia and precipitation with the present Cr(VI). However, in the whole, only 5.3% of Zn and 2.7% of Ni were separated, while the release of other heavy metals was almost ignorable. Although Pb mobility in the soil near the anode even increased three times, the overall metal mobility in all sample locations was found to significantly reduce under the electric field, indicating an effective stabilization approach. Moreover, compared with the bottom soil, the top soil near the anode was found to have a lower pH, higher moisture, lower heavy metal concentrations, and less soil oxidant demand; these phenomena may be due to a faster electro-migration of charged ions, especially H+, in the top soil. Therefore, such a divergence may considered to improve the current simulation approach for a realistic estimation of the actual metal and H+ electro-migration rate and the associated behavior under an electric field.

Chemical composition of red wines made from hybrid grape and common grape (Vitis vinifera L.) cultivars

Since the formulation of the French paradox, red grape wines are generally considered to be health-promoting products rather than culpable alcoholic beverages. The total wine production, totalling an equivalent of 30 billion 750 mL bottles in 2009, only verifies the fact that global demand is increasing and that the polyphenols present in wines are accounting for a significant proportion of the daily antioxidant intake of the general population. Both statements justify the interest of new regions to be self-sufficient in the wine production. Novel cold tolerant hybrid grape varieties also make it possible to produce wines in regions where winter temperatures fall below - 30 °C and the yearly sum of active temperatures does not exceed 1750 °C. Also the greater disease resistance of hybrid grapes - which allows production with less chemical plant protection agents - attracts attention. It is understood that the new regions and varieties raise questions about the quality of these wines. Therefore, the aim of our work was to determine to which extent wines produced from hybrid grapes differ from wines vinified from common grapes regarding their phenolic, saccharidic, and acidic spectra and elemental composition. Results demonstrate that although the polyphenolic spectra of red wines produced from hybrid grapes are generally similar to those of traditional wines, they show a wider range of anthocyanins, a balanced phenolic acid profile, qualitative differences in saccharide composition, and a very low heavy metal content.

Sulfate reduction at low pH to remediate acid mine drainage

Industrial activities and the natural oxidation of metallic sulfide-ores produce sulfate-rich waters with low pH and high heavy metals content, generally termed acid mine drainage (AMD). This is of great environmental concern as some heavy metals are highly toxic. Within a number of possibilities, biological treatment applying sulfate-reducing bacteria (SRB) is an attractive option to treat AMD and to recover metals. The process produces alkalinity, neutralizing the AMD simultaneously. The sulfide that is produced reacts with the metal in solution and precipitates them as metal sulfides. Here, important factors for biotechnological application of SRB such as the inocula, the pH of the process, the substrates and the reactor design are discussed. Microbial communities of sulfidogenic reactors treating AMD which comprise fermentative-, acetogenic- and SRB as well as methanogenic archaea are reviewed.

Bioremediation and fodder potentials of two Sargassum spp. in coastal waters of Shenzhen, South China

In this study, the bioremediation potentials of two seaweeds (Sargassum hemiphyllum and S. henslowianum) against pollution in a coastal mariculture area of Shenzhen, South China, were investigated by comparing the growth, nutrient bioaccumulation capacity of plants from the seaweed bed (control site) with plants from the fish farm. Results indicated that both species are potential candidates for bioremediation in the fish farm areas in terms of their high growth rates and high bioaccumulation capacities on inorganic nutrients. Both Sargassum spp. contain high levels of crude protein (11.7–14.0%) and crude fat (2.2–2.7%), suggesting high nutritional values. The S. hemiphyllum may serve as a good aquaculture fodder with high nutritional compositions and low heavy metal contents. However, heavy metals (Cr, Pb and Cd) of S. henslowianum exceed the maximum allowable concentrations as aquatic feed, which restricts its fodder application. In general, the results of this study may contribute to the marine pollution bioremediation in the coastal areas of South China, especially in mariculture zones.

Cr(vi), Pb(ii), Cd(ii) adsorption properties of nanostructured BiOBr microspheres and their application in a continuous filtering removal device for heavy metal ions

Uniform well-defined nanostructured BiOBr microspheres have been fabricated via a simple hydrothermal method in the presence of cetyltrimethylammonium bromide (CTAB) and ethylene glycol (EG). The heavy metal ion adsorption on the as-synthesized nanostructured BiOBr microspheres was systematically assessed by measuring the residual concentration during the adsorption process using a colorimetric method for Cr(VI) concentration, and an extraction-colorimetric method for Cd(II) and Pb(II) concentrations. The nanostructured BiOBr microspheres showed good removal capacity for heavy metal ions (Cr, Cd, Pb), and excellent adsorption properties for low concentration heavy metal ions, indicating potential applications in water purification. Based on the quick and efficient heavy metal ion removal ability of nanostructured BiOBr microspheres, a continuous filtering-type water purification device was designed and constructed. In using this continuous filtering type water purification device, 1 g of adsorbent can purify about 4900 g of Pb(II) contaminated water, 5900 g of Cd(II) contaminated water, or 21 500 g of Cr(VI) contaminated water having initial concentrations of 200 μg L−1 to successfully attain the World Health Organization standard for drinking water. The good removal capacity can be attributed to the hierarchical nanostructure, which displays a large specific surface area and strong adsorption of heavy metal ions.

Prediction of low heavy metal concentrations in agricultural soils using visible and near-infrared reflectance spectroscopy

In order to monitor the accumulation of heavy metals effectively and avoid the damage to the health of agricultural soils, a promising approach is to predict low concentrations of heavy metals in soils using visible and near-infrared (VNIR) reflectance spectroscopy coupled with calibration techniques. This study aimed to (i) compare the performance of a combination of partial least squares regression with genetic algorithm (GA-PLSR) against a general PLSR for predicting low concentrations of four heavy metals (i.e., As, Pb, Zn and Cu) in agricultural soils; (ii) explore the transferability of GA-PLSR models defined on one subset of land-use types to the other types; and (iii) to investigate the predictive mechanism for the prediction of the metals. One hundred soil samples were collected in the field locating at Yixing in China, and VNIR reflectance (350–2500nm) spectra were measured in a laboratory. With the entire soil samples, GA-PLSR and PLSR models were calibrated for the four heavy metals using a leave-one-out cross-validation procedure. The GA-PLSR models achieved better cross-validated accuracies than the PLSR models. For the transferability of GA-PLSR models, the soil samples were divided into three pairs of training sets and test sets from different land-use types. Three GA-PLSR models defined on the training sets had good transferability to the test sets, but nine GA-PLSR models were not successful. As for the predictive mechanism, besides the widely-used correlation analysis between OM and the metals, the relationship between the content of OM and the prediction accuracy of the metals was investigated and the similarity of the important wavelengths for OM and the metals was compared. The three methods verified that OM had a significant correlation with the predictions of the spectrally-featureless metals (Pb, Zn and Cu) from VNIR reflectance. We conclude that GA-PLSR modeling has a better capability for the prediction of the low heavy metal concentrations from VNIR reflectance, and it has a potential of transferability between different land-use types, and its accuracy is fundamentally influenced by OM.

Heavy metal records in the sediments of Nanyihu Lake, China: influencing factors and source identification

In 2008, three short sedimentary cores were collected from Nanyihu Lake in the lower Yangtze River Basin using a gravity corer. Heavy metals, including Pb, Cu, Zn, Cr, Ni, Mn, and major elements, including Al, Fe, K, Na, Mg and Ti, were measured. Radionuclides, including 210Pb and 137Cs, were analyzed to date the sediments. The significant Mn enrichment in the uppermost sediments of the three cores did not influence the distribution of Pb, Cu, Zn, Cr and Ni. The Pb, Cu, Zn, Cr and Ni contents have increased over the past 30–40 years. The decline of 206Pb/207Pb ratios toward the surface indicated increasing anthropogenic Pb loading to the lake sediments. However, the heavy metal enrichment was low overall because of the high sediment accumulation rates and the low anthropogenic heavy metal flux into the Nanyihu Lake.

Co-composting of pineapple leaves and chicken manure slurry

Abstract Background The common practice of clearing pineapple (Ananas comosus) residues for land preparation for cultivation is by burning, an unsustainable agricultural practice that causes environmental pollution. Chicken manure produced from the poultry industry is also increasing. Inappropriate disposal or treatment can pose harm to the environment and humans. In order to reduce environmental pollution, pineapple leaves and chicken manure slurry were co-composted to obtain high-quality organic fertilizer. The shredded pineapple leaves were thoroughly mixed with chicken manure slurry, chicken feed and molasses in polystyrene boxes. Co-compost temperature readings were taken three times daily. Results Nitrogen and P concentrations increased whereas C content was reduced throughout the co-composting. The CEC increased from 32.5 to 65.6 cmol kg-1 indicating humified organic material. Humic acid and ash contents also increased from 11.3% to 24.0% and 6.7% to 15.8%, respectively. The pH of the co-compost increased from 6.14 to 7.89. The final co-compost had no foul odour, low heavy metal content and comparable amount of nutrients. Seed germination indices of phytotoxicity test were above 80% of final co-compost. This suggests that the co-compost produced was phytotoxic-free and matured. Conclusion High-quality co-compost can be produced by co-composting pineapple leaves and chicken manure slurry and thus have potential to reduce environmental pollution that could result from poorly managed agricultural wastes.

Utilization of zeolite industrial wastewater for removal of copper and zinc from copper-brass pipe industrial wastewater

Utilization of zeolite industrial wastewater as a sorbent and (or) precipitant to remove Cu and Zn from copper-brass pipe industrial wastewater was conducted. These wastewaters were sampled and values for pH, temperature, biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total solids (TS), total dissolved solids (TDS), total suspended solids (TSS), and heavy metals were determined. In addition, the sorption isotherms of Cu and Zn in copper-brass pipe industrial wastewater onto solids of zeolite industrial wastewater at various dilutions of copper-brass pipe industrial wastewater were explored. The relationship between Cu and Zn concentrations and their removal efficiencies under different conditions of wastewater pH, contact times, and ratios between copper-brass pipe industrial wastewater and zeolite industrial wastewater was examined. Zeolite industrial wastewater contained various carbonate compounds that contributed to high pH and TDS values, and low heavy metals contamination whereas copper-brass pipe industrial wastewater had a low pH value and was contaminated with heavy metals, especially Cu and Zn. Application of zeolite industrial wastewater significantly increased the pH of copper-brass pipe industrial wastewater and consequently removed Cu and Zn. The increase in pH of the wastewater mixture significantly enhanced the heavy metals removal. The Langmuir equation described sorption isotherms of Cu and Zn onto solids of zeolite industrial wastewater at neutral pH (6 – 7) while the Freundlich equation fitted well at pH > 12. The maximum Cu (97% – 98%) and Zn (92% – 96%) removal efficiencies occurred at the original pH 12·8 of zeolite industrial wastewater, at the ratio of copper-brass pipe industrial wastewater to zeolite industrial wastewater 3:1 (vol.:vol.) and at 30 min contact time.

Adaptation strategies and referencing trial of Scots and black pine populations subjected to heavy metal pollution.

The impact of industrial heavy metal pollution on Scots pine (Pinus sylvestris L.) and black pine (Pinus nigra Arn.) populations was investigated. Sampled pine stands, which were located in Upper Silesia (southern Poland) in an area strongly polluted by heavy metals, consisted of resistant and sensitive trees. To evaluate the adaptation process, genetic structure and diversity was tested using isozyme analysis. Higher levels of Zn, Pb, Cd and Cu were detected in needles of sensitive trees compared with resistant ones. With respect to morphology, Scots pines were more distinctly impaired than black pines. Although black pines had lower heavy metal concentrations, levels in 1-year-old needles, other than Cu, significantly exceeded “reference plant” values (Markert 1994). In both species, resistant trees demonstrated a lower degree of genetic variation than metal-sensitive trees with respect to some enzyme loci (SHDH A, PGI, PGM, MDH C and DIA). This observation was corroborated in sensitive trees by the smaller number of identified alleles and alleles per locus, absence of private alleles and significant excess of homozygotes in relation to expected Hardy–Weinberg equilibrium values. Assuming that only resistant trees of both species survive under conditions of prolonged soil contamination, the observed genetic structure implies that remaining populations will be depleted of some alleles of unknown adaptive value to future selection pressures. Genetic changes induced by heavy metals suggest an important role for specific enzymes—FEST, SHDH A and B, GOT B and PGI—in the adaptation process. Our results may serve as a basis for selection and propagation of individuals appropriate for re-cultivation of areas chemically degraded by industrial activity.

Urban Mining: Quality and quantity of recyclable and recoverable material mechanically and physically extractable from residual waste

The mechanically sorted dry fraction (MSDF) and Fines (<20mm) arising from the mechanical biological treatment of residual municipal solid waste (RMSW) contains respectively about 11% w/w each of recyclable and recoverable materials. Processing a large sample of MSDF in an existing full-scale mechanical sorting facility equipped with near infrared and 2-3 dimensional selectors led to the extraction of about 6% w/w of recyclables with respect to the RMSW weight. Maximum selection efficiency was achieved for metals, about 98% w/w, whereas it was lower for Waste Electrical and Electronic Equipment (WEEE), about 2% w/w. After a simulated lab scale soil washing treatment it was possible to extract about 2% w/w of inert exploitable substances recoverable as construction materials, with respect to the amount of RMSW. The passing curve showed that inert materials were mainly sand with a particle size ranging from 0.063 to 2mm. Leaching tests showed quite low heavy metal concentrations with the exception of the particles retained by the 0.5mm sieve. A minimum pollutant concentration was in the leachate from the 10 and 20mm particle size fractions.

Stevioside increases the resistance of winter wheat to low temperatures and heavy metals

Stevioside increases the resistance of winter wheat to low temperatures and heavy metals

Heavy metal and element profiling of Brassica rapa

Heavy metal and element contents of two varieties of Brassica rapa (turnip) growing in the same environmental conditions and native to Egypt (Brassica rapa var. rapa) and to the Netherlands (Brassica rapa var. Raapstelen), respectively were evaluated by atomic absorption spectrophotometry. The results indicated that the Egyptian variety had higher concentrations of Mn and Zn at early developmental stages than the Dutch variety, whereas the Dutch variety showed higher concentration of Cu, Co and Na at late developmental stages. The basal second leaves in both varieties were characterized with higher concentrations of heavy metals compared to the upper fourth leaves at any developmental stage. The concentration of heavy metals and elements at any developmental stage is under the permissible levels set by FAO and WHO for human consumption and we recommend that the consumption of these vegetables is safe for humans if cultivated under the same conditions. The consumption of young leaves (upper fourth leaves) is much safer than that of the basal second leaves (in both varieties) due to their low heavy metal contents.

Spatial distribution and contamination assessment of heavy metals in surface soils of Hassi Messaoud, Algeria

An increase in heavy metal pollution in the soils of Hassi Messaoud (Algeria) due to intense industrialization and urbanization has become a serious environmental problem. There are three large industrial complexes that have been established in the region of Hassi Messaoud for petroleum extraction field and refinery. The region hosts several industrial facilities which are the main sources for hazardous wastes. Surface soil samples from 58 sampling sites (systematically sampled; 1 × 1 km regular grid), including different functional areas in Hassi Messaoud, were collected and analyzed. The results showed that the average concentrations of Cu, Ni, Mn, Pb and Zn in soil of Hassi Messaoud were up to 13.17, 35.78, 121.21, 130.97 and 61.08 mg/kg, respectively. Ni concentrations were comparable to background values, while Cu, Mn, Pb and Zn concentrations were higher than their corresponding background values. Among the functional areas, the industrial regions displayed the highest metal concentrations, while the lowest concentrations occurred in rural soil. Principal component analysis coupled with cluster analysis showed that: (1) Pb and Zn had anthropogenic sources; and (2) Ni, Cu and Mn were associated with parent materials. Contaminations in soils were classified as geoaccumulation index and enrichment factor. Pollution index values of Cu, Ni, Mn, Pb and Zn varied in the range of 0.04–5.41, 0.46–2.49, 0.01–5.73, 0.62–152.9 and 0.09–53.01, with mean values of 1.32, 1.08, 1.26, 5.64 and 3.1, respectively. The integrated pollution index (IPI) of all the analyzed samples varied from 0.42 to 31.59, with a mean of 2.48, and more than 5.45 % of samples are extremely contaminated; 18.18 % are heavily contaminated; 60 % are moderately contaminated; and others are low contaminated. The spatial distribution of IPI showed that desert and rural areas displayed relatively lower heavy metal contamination in comparison with other areas.

Chemical characterization of pruned vine shoots from La Rioja (Spain) for obtaining solid bio-fuels

Every year thousands of tonnes of biomass waste in the form of pruned vine shoots are produced in the Spanish region of La Rioja. This study, the first of its kind to be conducted in the region, examines how this waste can be valorised, mainly as an energy source. Representative samples were taken from the different varieties and vineyards in the region. Each batch of samples was then chemically characterised to learn its moisture content, percentage of ash, composition in terms of elements and heating power. The influence of various factors on these chemical properties was analysed. Only two factors proved to be of statistically significant importance: variety and training method. The expected performance in combustion of vine shoots of the region's predominant variety, Tempranillo, was estimated. Undoubted advantages were found, such as a significantly higher heating value (16 900 kJ/kg), moderate quantities of ash, medium aerosol emission rates, no expected problems of corrosion due to S or Cl, and a very low heavy metal content. In actual collection conditions, thermal energy from vine shoots after chopping (to between 30 and 100 mm), with a moisture content of less than 20%, would cost 2.45 euro cents/kWh to produce. The best way of using this residue is considered to convert it to fuel for generating heat and electricity on a small scale, to supply the needs of vineyards themselves or nearby locations.