SPATIAL DISTRIBUTION OF COPPER FRACTIONS IN A VINEYARD SOIL

The aim of this work is to assess the effect of planting patterns on the spatial distribution of total copper and other Cu fractions in vineyard soils. Both classical and geostatistical tools were used for the study. The soil of the plot had a loam texture and was strongly acid. The mean total Cu concentration (Cu_T) was 368 mg kg⁻¹. The mean value of potential available fractions was 188 mg kg⁻¹ for Cu_EDTA and 122 mg kg⁻¹ for Cu_DPTA, whereas the mean exchangeable Cu (Cu_EX) was 5·2 mg kg⁻¹. All Cu measurements exhibited a wide variation. These values are very high compared with those found in non‐polluted soils, and they can affect the soil, plants and microorganisms. The best correlation for Cu_EX was with soil pH, whereas for Cu_EDTA, Cu_DPTA, and Cu_T, the best correlation was with soil organic carbon. Directional semivariograms were fitted with a spherical model (parallel to plant rows) and a periodic model (perpendicular) showing a dependence on orientation and distance. All Cu measurements were higher along plant rows than among them, finding a periodic pattern in the variance for the normal direction from plant rows. However, in site‐specific management, it is crucial not only to describe the pattern of variation but also to estimate the Cu content in the soil. Copper concentration maps were estimated by kriging interpolation. These maps show a higher Cu accumulation along the cultivated rows than the uncultivated rows. Copyright © 2011 John Wiley & Sons, Ltd.     

Short‐scale distribution of copper fractions in a vineyard acid soil

We studied short‐scale variation in the total concentration of copper and its fractions in a soil vineyard. Soil samples were collected at a depth of 0–20 cm between plant rows (1), between individual plants (2) and at their base (3) in a vine‐grown plot in NW Spain. The mean total content in Cu (Cu_t) in the soil was found to be 97 mg kg⁻¹ and that of potentially available Cu (Cu_EDTA) 34 mg kg⁻¹. Copper bound to organic matter (Cu_OM) and to non‐crystalline inorganic soil components (Cu_IA) were the dominant fractions and accounted for 34% of total copper each. The contents in exchangeable (Cu_e), pyrophosphate‐extractable (Cu_p), oxalic/oxalate‐extractable (Cu_o) and total copper (Cu_t) exhibited statistically significant correlations with pH, sum of base cations (S), cation‐exchange capacity (CEC) and exchangeable calcium (Ca_e). Both total and fractional copper contents were higher in plant rows than between them, particularly in the centre of the plot. Also, Cu_OM and Cu_IA were higher in planting rows than between rows. These copper results may have been influenced by the vine‐growing practices of the area and also by the distribution of plants and their pruning. This variability pattern for Cu distribution is crucial with a view to minimising potential adverse effects of fungicides and optimising any reclamation treatments needed. Copyright © 2007 John Wiley & Sons, Ltd.     

铜对土壤中功夫菊酯和氯氰菊酯迁移和扩散的影响

Repeated applications of bordeaux mixture （a blend of copper sulfate and calcium hydroxide） and pyrethroid insecticides （Pys） have led to elevated copper （Cu） and Pys concentrations in vineyard surface soils. To understand the potential influence of Cu on the fate of Pys in the soil environment, we selected two Pys, cypermethrin （CPM） and lambda-cyhalothrin （λ-CHT）, and two typical Chinese vineyard soils, Haplic Acrisol and Luvic Phaeozem, as experimental samples. The dissipation experiment was conducted at room temperature in the dark, and the transport of both Pys through the soils was investigated using soil thin-layer chromatography. The results showed that the transport of Pys in both soils increased as the Cu²⁺ concentration increased from 0 to 100 mg L^-1 , and Pys were more transportable in Haplic Acrisol （HA） than in Luvic Phaeozem （LP） under the same experimental conditions. For CPM, only 100 mg L^-1 of Cu²⁺ significantly （P<0.05） increased Pys transport through both soils relative to water. Lambda-CHT was significantly （P<0.05） transported through HA by all the Cu²⁺ concentrations compared to water, and all but the 1 mg L^-1 of Cu²⁺ significantly （P<0.05） increased the transport of λ-CHT through LP relative to water. However, the dissipation rates of CPM and λ-CHT decreased with the addition of Cu to soils. Our findings suggest that the risk of groundwater contamination by Pys increases in the soils with elevated Cu concentrations.     

Distribution of Copper in Sediments from Fluvial Reservoirs Treated with Copper Triethanolamine Complex Algicide

The control of algal growth in water reservoirs with copper-based algicides leads to elevated sediment Cu concentration and thus could affect long-term water quality. To assess the potential mobility of sediment-associated Cu, a study was conducted using samples from three drinking water reservoirs treated with Cutrine®, a copper triethanolamine complex algicide. Total Cu (Cu_T) in treated reservoir sediment ranged from 13.3 to 139.9 mg Cu kg^?1 and was on average 1.5 times the level in streams (48 mg Cu kg^?1) flowing into the reservoirs. Sediment Cu_T and algicide application history indicated the retention of 82–93% of the algicide Cu applied. Sequential extraction showed that Cu primarily accumulated in the residual fraction (60%), whereas the potentially mobile pools (water extractable: Cu_H2O, exchangeable: Cu_EX, organic bound) accounted for <10% of Cu_T. The leachable Cu fraction (extracted with 1 M acetic acid) also amounted to <9% of Cu_T and was related negatively to C/N and positively to H/C ratios of organic matter. In addition, these potentially mobile fractions were found to be related, not to total organic C, but to sediment respiration suggesting that the potentially mobile Cu fractions were primarily associated with aliphatic and readily biodegradable C (more so than total organic C). During a 2-year period without algicide treatment (that followed 4 years of repeated algicide applications to one of the studied reservoirs), mean dissolved Cu (micrograms per liter) in the reservoir (39.2) was similar to levels measured at locations upstream (43.3) and downstream (47.2) from the reservoir. These results indicate that the bulk of sediment Cu is associated with geochemically stable solid phases and thus should alleviate concerns about Cu transfer into the water column.     

Anthropogenic Heavy Metal Pollution in the Surficial Sediments of the Keratsini Harbor, Saronikos Gulf, Greece

The contents of ten elements [Cd, Pb, W, Zn, Mn, As, Se, Cr, Cu, and organic carbon (C_org)] have been determined in the surficial sediments of Keratsini harbor, Saronikos Gulf, Greece. The contamination of the sediments was assessed on the basis of geoaccumulation index and to corresponding sediment quality guidelines (SQGs) effects range low/effects range median. The results revealed highly elevated Cd, Pb, W, Zn, As, Se, Cr, Cu, and C_org values (Cd, 190–1,763 mg kg^?1; Pb, 521–1,263 mg kg^?1; W, 38–100 mg kg^?1; Zn, 409–6,725 mg kg^?1; Mn, 95–1,101 mg kg^?1; As, not detectable–1,813 mg kg^?1; Se, not detectable–58 mg kg^?1; Cr, 264–860 mg kg^?1; Cu, 195–518 mg kg^?1; and C_org, 0.69–4.41%). The enrichment of metals in the sediments results from the contribution of the central Athens sewage outfall through which the waste of the Attica basin ends up in Keratsini harbor as well as from industrial and ship contaminants.     

Mineralization and Nutrient Release of an Organic Fertilizer Made by Flour,Meat, and Crop Residues in Two Vineyard Soils with Different pH Levels

The mineralization and nutrient evolution of an organic fertilizer compost of flour, meat, and crop residues was evaluated in two vineyard soils. A lysimetric testing, using 2.2-L Büchner funnels, was carried out to study the evolution of pH, electrical conductivity, and nutrients during the 400-day experiment. The net mineralization for two different doses of the fertilizer mixed with the soils was compared with an unfertilized control. The pH value of the acidic soil decreased to values less than 4.5 because of the yield of hydrogen (H⁺) in the organic fertilizer mineralization, whereas the soluble aluminium (Al³⁺) increased quickly in the leachates. The mineralization process was quicker in the alkaline soil (with a maximum mineralization rate of 0.83 mg nitrogen (N) kg^?1 day^?1 for the 8 Mg ha^?1 dose and 0.43 mg N kg^?1 day^?1 for the 4 Mg ha^?1 dose) in comparison with the acidic soil, which reduced these rates up to 50%. The N-nitrate (NO₃) amounts yielded in a year were 150 and 79 kg N ha^?1 for the 8 and 4 Mg ha^?1 doses respectively in the alkaline soil, enough to cover the vineyard N demand. These values were reduced to 50% and 60% of N-NO₃ for the acidic soil, indicating the important effect of pH in the mineralization.     

Effect of copper on nitrous oxide reduction in freshwater sediment

The effect of Cu(II) sulfate on N20 reduction was studied in anaerobically incubated freshwater sediment at 15 °C. At Cu concentrations from 100 to 5000 μg g^?1, a concentration-dependent decrease in sediment pH was observed in conjunction with a decrease in N₂0 reduction in Cu²⁺ treated sediment in flask-microcosms analyzed immediately after metal addition. However, if flask-microcosms were amended with Cu²⁺ and then pre-incubated to allow the sediment pH to naturally return to its original pH (7.1), an inhibitory effect was only produced at 5000 μg Cu g^?1 sediment. Copper retention studies showed that up to 96.4% of the added Cu²⁺ (2500 μgg^?1) was retained by sediment.     

Influence of pH on the release and chemical fractionation of heavy metals in sediment from a suburban drainage stream in an arid mine-based oasis

Purpose

The objectives of this study were to explore the influences of pH on the release of Cu, Zn, Cd, Pb, Ni, and Cr in sediments derived from the upstream, middle, and downstream reaches of Dongdagou stream in Gansu Province, Northwest China, and to examine the fractionation changes of heavy metals in the sediments after reaching their release equilibrium under different pH conditions.

Materials and methods

Sediment samples were obtained using a stainless steel grab sampler to collect the uppermost 10 cm of sediment from the channel bed. The pH-dependent release experiment was conducted in the solid-to-liquid ratio of 1:20 at different pH values (2, 4, 6, 8, 10, and 12) at room temperature. The total Cu, Zn, Cd, Pb, Ni, and Cr concentrations in the sediments were digested using an acid digestion mixture (HNO₃ + HF + HClO₄) in an open system. Metal fractionation of selected sediments was obtained using the Tessier sequential extraction procedure. Heavy metal concentrations in the samples were determined using atomic absorption spectrophotometry.

Results and discussion

The mean concentrations of heavy metals in sediments decreased in the following order: Zn (1676.67 mg kg^?1) > Pb (528.65 mg kg^?1) > Cu (391.34 mg kg^?1) > Cr (53.48 mg kg^?1) > Ni (34.27 mg kg^?1) > Cd (11.53 mg kg^?1). Overall, the solubility of Cu, Zn, Cd, Pb, and Ni decreased with increasing pH, and they were strongly released at pH 2. Moreover, the solubility of Cr increased with increasing pH, and its release was highest at pH 12. After reaching the release equilibrium of heavy metals under different pH conditions, the percentages of organic Cu, Zn, Cd, and Fe-Mn oxyhydroxide Pb decreased, compared to their initial fractions. The residual fractions of Ni and Cr were dominant, regardless of pH.

Conclusions

The average concentrations of Cu, Zn, Cd, and Pb in sediments were highly elevated compared with the soil background values in Gansu Province, China. The results of this pH-dependent release experiment showed that the release behaviors of Cu, Zn, Pb, and Cr followed an asymmetric V-shaped pattern, whereas Cd and Ni followed an irregular L-shaped pattern. The changes in the release of heavy metals in sediments were related to their redistribution between chemical fractionations.

     

The behavior of selected chlorinated organic micropollutants in the activated sludge process: A pilot plant study

The effects of Cu(II) sulfate on sediment respiration were investigated in a 3-phase aquatic microcosm, containing a calcareous, southern Ontario stream sediment. In Cu²⁺ treated flask-microcosms, with the pH restored to 7.1, both aerobic and anaerobic CO₂ evolution were unaffected by 5000 jig Cu g^?1 sediment over a 40-day period at 15 °C. Oxygen consumption in sediment was initially unaffected by 5000 μg Cu g^?1. However, after 35 to 40 days, a significant reduction of 28% was observed. The added Cu^?2+ was removed from the water column and the sediment solution. In microcosms containing 5000 μg g^?1 of total Cu, only 1.00 ± 0.76 μg g^?1 was water soluble Cu, and the free cupric cation (Cu²⁺) concentration was below the detection limit of the specific ion electrode (less than 0.01 μg g^?1). Maximum Cu retention (98.6%) was observed at 2800 μg Cu g^?1, above which fractional retention decreased. In a calcareous, organic rich, sediment of pH 7.1, Cu⁺ was essentially unvailable to exert a toxic effect on respiration.     

Pine Bark Amendment to Promote Sustainability in Cu-Polluted Acid Soils: Effects on <Emphasis Type="Italic">Lolium perenne</Emphasis> Growth and Cu Uptake

The establishment of a complementary grass cover on vineyard soils can promote sustainability of the affected environment. In this work, we used an acid vineyard soil with total Cu concentration 188 mg kg^?1 to study the influence of pine bark amendment on Lolium perenne growth and Cu uptake. The results indicate that the pine bark amendment did not cause a significant increase in the mass of the shoots of Lolium perenne, but favored the root biomass: 0.034 g for control and 0.061 g for soil samples amended with 48 g kg^?1 of pine bark. Moreover, the pine bark amendment decreased Cu concentration in both, shoots (50 mg kg^?1 for control soil and 29 mg kg^?1 for soil amended with 48 g kg^?1 pine bark) and roots (250 mg kg^?1 for control soil and 64 mg kg^?1 for soil amended with 48 g kg^?1 pine bark). The main factor responsible for these results was a significant decrease of the most mobile fractions of Cu in the soil. Those fractions were extracted using ammonium acetate, ammonium chloride, sodium salt of ethylene-diamine-tetraacetic acid (EDTA-Na), and diethylene-triamine-pentaacetic acid (DTPA).     

Distribution of Heavy Metals in Near-Shore Sediments of the Swan River Estuary,Western Australia

Estuarine systems adjacent to urban areas are at risk of contamination by contaminants from anthropogenic sources, such as heavy metals. We anticipated that the sediments of the Swan River estuary, which runs through metropolitan Perth in Western Australia, would show metal contamination related to industrialization and inputs of stormwater. Total Cu, Pb and Cd concentrations, and Cu, Pb, Cr and Zn inoperationally-defined fractions, were determined inseparate sampling exercises in near-shore sediments ofthe upper Swan River estuary.Total metal concentrations in sediments were not high (maximum values of 297 mg kg^-1 for Cu, 184 mg kg^-1 for Pb and 0.9 mg kg^-1 for Cd) when compared with Australian environmental assessmentguidelines for soils. On the basis of linear regressions between sediment metal concentrations andphysicochemical properties of the sediments (pH, organic carbon, particle size distribution), no single parameter could explain the variation in metal concentrations for all metals. Sediment organic carbon content was positively correlated with Cu concentration; Cu concentrations also increased significantly with increasing clay content anddecreasing sand content. Pb concentrations showed a significant increase with increasing sediment pH, and were approximately three-fold higher in sediments adjacent to stormwater drain outfalls than in sediments remote from drains; no such effect was observed for Cu or Cd. No effect of distance downstream was observed. Sequential extraction of sediments showed that most of the metals were in relatively immobile forms, for example bound to Feoxides, or only extractable by aqua regia. The enhanced concentrations of Pb near stormwater outfalls suggest that vehicle-derived Pb may be an important contributor of Pb to the estuary.     

Copper Accumulations in Soils,Coffee, Banana,and Bean Plants Following Copper-Based Fungicides in Coffee Farms in Arusha and Kilimanjaro Regions,Tanzania

This study was carried out to investigate the levels of copper (Cu) contamination in coffee fields in Kilimanjaro and Arusha regions, Tanzania, to increase the database on the contamination of soils by Cu-based fungicides in coffee fields. Surface (0–20 cm deep) soil samples were collected from different farms in Kilimanjaro and Arusha regions. Coffee, banana, and bean plant samples were collected from the locations of soil sampling. Soil and plant samples were analyzed at the Department of Soil Science, Sokoine University of Agriculture, Morogoro, Tanzania. It was found that the calcium chloride (CaCl₂)–extractable Cu was less than the detection limit of flame atomic absorption spectrometry. Diethylenetriaminepentaacetic acid (DTPA)–extractable (24 to 366 mg Cu kg^?1 soil) and aqua regia–extractable (80 to 806 mg Cu kg^?1 soil) Cu levels were high enough to raise environmental alarm (based on European Union guidelines) in the Cu fungicide–treated soils as compared with natural Cu levels in untreated soils (1 to 12 mg Cu kg^?1 soil for DTPA and 22 to 32 mg Cu kg^?1 soil for aqua regia–extractable Cu). Coffee, banana, and bean plants grown on soils contaminated by Cu fungicides had varied concentrations of Cu that were greater than the concentrations of Cu in the plants collected from the uncontaminated soils. Stepwise regression analysis carried out to investigate the relationships between the soil properties and the concentrations of Cu in plants revealed a significant (P = 0.01) positive relationship (R² = 0.4) between organic carbon and the concentration of Cu in banana leaves. Aqua regia–extractable Cu was positively correlated (P = 0.03, R² = 0.4) with the concentrations of Cu in banana leaves. For bean leaves, electrical conductivity (EC) had a positive significant (P = 0.01) relationship (R² = 0.56) with the concentrations of Cu in the plants. It is recommended that further research be carried out to investigate the dynamics and bioavailability of Cu for the different crops interplanted in the coffee fields.     

EDTA Leaching of Cu Contaminated Soils Using Ozone/UV for Treatment and Reuse of Washing Solution in a Closed Loop

Ozone and UV irradiation were used for oxidative decomposition of EDTA-Cu complexes in washing solution obtained during multi-step leaching of Cu (344,1?±?36.5 mg kg^?1) contaminated vineyard soil with EDTA as a chelant. The released Cu was absorbed from the washing solution on a commercial mixture of metal absorbing minerals, and the treated washing solution then reused for removal of soil residual Cu-EDTA complexes in a closed-loop process. Six consecutive leaching steps (6?×?2.5 mmol kg^?1 of EDTA) removed 38.8 % of Cu from soils, and reduced Cu soil mobility, determined using the toxicity characteristic leaching test (TCLP), by 28.5%. The final washing solution obtained after soil remediation was colourless, with a pH close to neutral (7.5?±?0.2) and with low concentrations of Cu and EDTA (0.51?±?0.22 mg L^?1 and 0.083 mM, respectively). The proposed remediation method has therefore potential not just to recycle and save process water, but also not to produce toxic wastewaters. Soil treatment did not substantially alter the soil properties determined by pedological analysis, and had relatively little impact on soil hydraulic conductivity and soil water sorption capacity.     

Fate and Transport of Copper Applied in Channel Catfish Ponds

A pilot-scale study and field measurements at commercial ponds were conducted to investigate the environmental fate of copper (Cu) applied as an algaecide in commercial catfish ponds. In the pilot study, a total of 774 g Cu(II) was applied to an experimental catfish pond over a period of 16 summer weeks. More than 90% of Cu applied became associated with suspended sediment particles within a few minutes of addition, and then nearly all Cu applied was transferred to the sediment phase within about 2 days. At the end of the study, the peak Cu content in the sediment increased from an initial concentration of 25～35 mg kg^?1 to about 200 mg kg^?1, and the applied Cu was able to reach a sediment depth of about 16 cm. Meanwhile, Cu concentration in the catfish body decreased from 12.7 ± 2.81 mg kg^?1 to 6.15 ± 2.54 mg kg^?1. Copper mass balance indicated that virtually all Cu applied was retained in the sediment. Only 0.01% of the total Cu applied was taken up by fish and 0.1% remained in pond water. Data from 3 commercial fishponds of different ages (1–25 years) and with different sediment types (acidic, neutral and calcareous) supported the pilot-scale observation. Both pilot-testing results and field measurements revealed that Cu is predominantly accumulated within the top sediment layer and barely reached the bottom soil regardless of the pond age and the type of the sediments. Field monitoring of groundwater quality suggested that the copper leaching into the groundwater surrounding the ponds was insignificant.     

Corn response to six annual Cu-enriched pig manure applications to three soils

The increasing use of land application of organic wastes presents a potential pathway for metals to enter the environment and cause phytotoxicity. Studies to evaluate the response of corn (Zea mays L.) to annual applications of Cu-enriched pig manure or CUSO₄ were established as ongoing field experiments in 1978 on three soils. The soils varied in texture from fine sandy loam to clay loam and ranged in CEC from 5.0 to 12.3 cmol(+) kg^?1. Five treatments in each field experiment consisted of a control, low and high Cu-enriched pig manure levels, and low and high CuSO₄ levels. After 6 yr 638 Mg ha^?1 of wet Cu-enriched pig manure containing from 185 to 198 mg Cu kg^?1 had been applied for the high treatments on the three soils. The Cu-enriched pig manure, which contained 1290 mg Cu dry kg^?1, was produced by pigs fed diets with 242 mg Cu kg^?1. In the sixth year, leaf blade Cu concentrations were increased by ≤ 3.3 mg kg^?1 due to the high Cu treatments but remained in the middle of the Cu sufficiency range. Grain Cu was 73 to 84% lower than blade Cu and was unaffected by the treatments. The DTPA (diethylenetriaminepentaacetic acid) extractable Cu was not related to either leaf or grain Cu levels. However, the DTPA extractable Cu was linearly related, r = 0.92, to applied amounts of Cu in the three soils. Overall, this research indicated that application of up to 638 Mg kg^?1 of wet Cu-enriched pig manure did not cause an environmental hazard.     

Role of soil constituents in fixation of soluble Zn, Cu, Ni and Cd added to soils

Slow immobilization of trace metals in soil, termed ‘fixation’, affects their natural attenuation but it is still unclear which reactions occur. Twenty‐eight soils were selected to assess the role of Fe oxides and carbonates on fixation of Cu, Cd, Zn and Ni. Soils included samples from 2 toposequences (Vietnam, Spain) and 13 European topsoils with different soil characteristics (pH 3.4–7.7). Samples were amended with 250 mg Zn kg⁻¹, 100 mg Cu kg⁻¹, 80 mg Ni kg⁻¹ and 2.5 mg Cd kg⁻¹ as metal salts and incubated for 850 days. Fixation was measured as the increase of the fraction of added metals that were not isotopically exchangeable. Fixation increased with time and was, averaged over all the soils, 43% (Cu), 41% (Zn), 41% (Ni) and 28% (Cd) after 850 days. Metal fixation within samples from each toposequence was generally positively related to total Fe oxide concentration (Fe_d) for Zn, Ni and Cd. However, the fixation of Cd, Zn and Ni was mainly explained by pH and not by Fe_d when considering all soils. Fixation of Zn and Cd in soils with pH >7.0 increased with increasing concentrations of carbonates at initial ageing times. Fixed fractions of Zn, Ni and Cd were significantly released when experimentally removing 50% of carbonates by acidification. Fixation of Cu was most poorly related to soil properties. Our data suggest that fixation of Cd, Zn and Ni is related to a pH‐dependent diffusion into oxides and that of Cd and Zn also to diffusion and/or coprecipitation in carbonates. Fixation of Ni at neutral pH may also be related to stabilization of precipitates that form readily in soil.     

Heavy metal pollution of agricultural soils and sediments in Liaoning Province,China

Heavy metal pollution of soils and sediments in Liaoning Province, Northeast China, was investigated. Fifty seven samples of agricultural soils and 8 samples of sediments were collected in 1996 from paddy or upland fields and irrigation channels, respectively, in Shenyang, Fushun, Liaoyang, Anshan, and Tieling regions, and concentrations of total and 0.1 mol L^-1 HCI-extractable Cd, Cu, Pb, and Zn were analyzed using ICP spectrometry. Seventeen samples of unpolished rice were also collected from selected paddy fields and total concentrations of the four elements were determined.–

Both paddy and upland soils were polluted with Cd: average total concentration was 0.70, 0.57, and 0.53 mg kg^-1 in the western and southern parts of Shenyang, and Anshan, respectively, and significantly higher than the background level of 0.32 mg kg^-1. Cd concentrations of four samples exceeded even 1 mg kg^-1, which corresponds to the critical level of Cd contamination in China. About 65% of the total Cd was extracted with 0.1 mol L^-1 HCI, suggesting that Cd was relatively mobile compared with other metals. The level of Cd pollution was, however, lower than that previously reported and serious polIution was not observed for Cu, Pb, and Zn. Accordingly, Cd concentration in upland rice was within the range of the unpolluted level in this study. Nevertheless, Cd concentration in a sediment of irrigation channels in the western part of Shenyang exceeded 16 mg kg^-1, indicating the possibility of further contamination of agricultural soils. In conclusion, soils and sediments were still polluted with Cd in the southern part of Shenyang, Anshan, and especially in the western part of Shenyang, and further countermeasures are urgently required to ensure safe food production in these regions.     

Effects of Broiler Litter Management Practices on Phosphorus,Copper, Zinc,Manganese, and Arsenic Concentrations in Maryland Coastal Plain Soils

Abstract

The objective of this research was to assess the long‐term effects of broiler litter applications on soil phosphorus (P), copper (Cu), zinc (Zn), manganese (Mn), and arsenic (As) concentrations in Chesapeake Bay watershed Coastal Plain soils. Litter and soil samples were collected from 10 farms with more than 40 years of broiler production and from wooded sites adjacent to fields and were analyzed for P and metal contents. Averaged over farms, total P and metal concentrations in the litter were 12.8 g kg^?1 P and 332, 350, 334, and 2.93 mg kg^?1 Cu, Zn, Mn, and As, respectively. Surface (0–15 cm) soil pH values were greater than (5.7–6.4) the 0‐ to 15‐cm depth at wooded sites (3.5–4.3). Surface soil Bray 1 P values (149–796 mg kg^?1) in amended fields were greater than wooded sites (4.4–17 mg kg^?1). The 1N nitric acid (HNO₃)–extractable metal concentrations were higher in amended soils than in wooded areas and were 7.7–32, 5.7–26, 12.3–71, and 0.6–3.0 mg kg^?1 for Cu, Zn, Mn, and As, respectively, compared to 0.76–14, 4.6–22, 1.6–70, and 0.14–0.59 mg kg^?1 for the same metals, respectively, in wooded areas. Results from this study demonstrated that long‐term broiler litter applications have altered the chemical properties of the Coastal Plain soils of the Maryland Eastern Shore. Metal concentrations were low in the surface layer of amended fields and typically decreased with depth. Phosphorus additions rather than metals are most likely to contribute to the degradation of the Chesapeake Bay watershed.     

Metal uptake in maize, willows and poplars on impoldered and freshwater tidal marshes in the Scheldt estuary

Foliar Cd and Zn concentrations in Salix, Populus and Zea mays grown on freshwater tidal marshes were assessed. Soil metal concentrations were elevated, averaging 9.7 mg Cd kg^?1 dry soil, 1100 mg Zn kg^?1 dry soil and 152 mg Cr kg^?1 dry soil. Cd (1.1–13.7 mg kg^?1) and Zn (192–1140 mg kg^?1) concentrations in willows and poplars were markedly higher than in maize on impoldered tidal marshes (0.8–4.8 mg Cd kg^?1 and 155–255 mg Zn kg^?1). Foliar samples of maize were collected on 90 plots on alluvial and sediment‐derived soils with variable degree of soil pollution. For soil Cd concentrations exceeding 7 mg Cd kg^?1 dry soil, there was a 50% probability that maize leaf concentrations exceeded public health standards for animal fodder. It was shown that analysis of foliar samples of maize taken in August can be used to predict foliar metal concentrations at harvest. These findings can therefore contribute to anticipating potential hazards arising from maize cultivation on soils with elevated metal contents.     

Sorption of copper (II) and sulphate to different biochars before and after composting with farmyard manure

Biochar application has been suggested for reducing toxic levels of metals in contaminated soils and enhancing nutrient retention in agro‐ecosystems. We studied sorption of copper (Cu(II)) and sulphate‐sulphur (SO₄‐S) to charcoal, gasification coke and flash‐pyrolysis biochar in order to relate sorption to char properties. Furthermore, we investigated the effect of composting of charcoal and gasification coke on sorptive properties. Langmuir sorption affinity coefficients for Cu(II) for non‐composted biochars increased in the order flash‐pyrolysis char < charcoal < gasification coke. The sorption capacity for Cu(II) of the chars decreased in the order gasification coke (629 mg kg^?1) > flash‐pyrolysis char (196 mg kg^?1) > charcoal (56 mg kg^?1). Composting significantly increased the sorption affinity coefficient approximately by a factor of 5 for charcoal (up to 1.1 l mg^?1) and by a factor of 3–4 for gasification coke (up to 3.2 l mg^?1). Whereas Cu(II) sorption to gasification coke (composted or not) was largely irreversible, sorption to flash‐pyrolysis char and charcoal showed higher reversibility. Relationships between Cu(II) sorption and biochar properties such as cation exchange capacity, specific surface area or aromaticity suggest that sorption was largely determined by complexation with organic matter. Sorption of SO₄‐S was negligible by non‐composted and composted biochars. Composted gasification coke might be suited to reducing toxic Cu(II) concentrations in contaminated soils. Composted charcoal can potentially improve Cu(II) retention in a plant available form in acidic, sandy soils with small organic matter contents. Transient effects of biochars on soil pH can over‐ride the influence of sorption to biochars on concentrations of trace elements in soil solution and their availability to plants.