The effect of organic materials on the mobility and toxicity of metals in contaminated soils

Organic materials such as compost are often proposed as suitable materials for the remediation of contaminated brownfield sites intended for soft end-use. In addition to vitalising the soil, they are also believed to immobilise metals thereby breaking contaminant-receptor pathways and reducing the ecotoxicity of the contaminants. However, some research has demonstrated contradictory effects between composts on metal immobilisation. In the present study, four different composts and a liming product containing organic matter (LimeX70) were tested to examine both their metal retention and toxicity reduction capabilities on three different metal contaminated soils. Leaching tests, a plant growth test with Greek cress (Lepidium sativum), an earthworm (Eisenia fetida) survival and condition test and a bacterial toxicity test using Vibrio fischeri were carried out. The leaching test results showed that spent mushroom compost caused an increase in metal concentration in the leachates, while LimeX70 caused a decrease. The variation in behaviour between different amendments for each soil was high, so a generic conclusion could not be drawn. Toxicity tests showed significant reduction of metal bioavailability and toxicity for Greek cress, earthworms and bacteria. The results also suggest that more research should be undertaken to understand the mechanisms involved in metal complexation using different types of organic matter, in order to optimise the use of organic materials like compost for soil remediation. Crown Copyright (C) 2007 Published by Elsevier Ltd. All rights reserved.

In situ degradability of dry matter and neutral-detergent fibre of thorn scrubland forage consumed by goats in the semi-arid region of north Mexico

Three goats provided with oesophageal and ruminal cannulae were used to determine variations in dry matter (DM) and neutral-detergent fibre (NDF) degradability of the forage consumed when grazing thorn scrubland in the semi-arid region of north Mexico, during two consecutive dry and wet periods. Ingesta samples were incubated intraruminally, the data were fitted to the exponential equation P = a + b (1-e(-ct)) and statistically analysed using a randomized-block design. Organic matter and crude protein (CP) contents were higher (P < 0.05) in the wet seasons. Values of NDF were similar in dry and wet season of both years whereas higher numerical values of acid-detergent fibre (ADF), lignin and cellulose were registered in the dry seasons. DM and NDF degradabilities after 24 and 48 h of ruminal incubation were higher (P < 0.05) in the wet seasons. Higher values (P < 0.05) in DM and NDF bag losses at zero time (A fraction) were registered in the two wet seasons. The insoluble but fermentable DM and NDF (B fractions) were higher (P < 0.05) in the 1999 wet season and variable in the rest of the studied period. Numerically higher values of DM and NDF c fraction were found in wet periods, whereas DM and NDF potential degradabilities were higher (P < 0.05) in the wet season in 1999 and similar across seasons in 2000. Lowest (P < 0.05) contents of CP in grazed forage, DM and NDF degradabilities after 48 h of ruminal incubation, and A, and B, and c fractions were observed in the dry seasons. Thus, these results may be related to both the lower feeding value of forage consumed by the animals and lower performance of livestock during this period. Then, the DM and NDF degradability after 48 h, together with the insoluble but fermentable matter and the c fraction permit the nutritive value of the forage consumed by grazing goats to be accurately described.

Effects of cultural system (organic and conventional) on growth, photosynthesis and yield components of sweet corn (zea mays L.) under semi-arid environment

Organic sweet maize consists of a new industrial crop product. Field experiment was conducted to determine the effects of cultural systems on growth, photosynthesis and yield components of sweet maize crop (Zea mays L. F-1 hybrid 'Midas'). A randomized complete block design was employed with four replicates per treatment (organic fertilization: cow manure (5, 10 and 20 t ha(-1)), poultry manure (5, 10 and 20 t ha(-1)) and barley mulch (5, 10 and 20 t ha(-1)), synthetic fertilizer (240 kg N ha(-1)): 21-0-0 and control). The lowest dry weight, height and leaf area index and sod organic matter were measured in the control treatment. Organic matter content was proportionate to the amount of manure applied. The control plots had the lowest yield (1593 kg ha(-1)) and the double rate cow manure plots the had,greatest one. (6104 kg ha(-1)). High correlation between sweet corn yield and organic matter was registered. Moreover, the lowest values of 1000-grain weight were obtained with control plot. The fertilizer plot gave values which were similar to the full rate cow manure treatment. The photosynthetic race of the untreated control was significantly lower than that of the other treatments. The phorosynthetic rate increased as poultry manure and barley mulch ram decreased and as cow manure increased. Furthermore the untreated control had the lowest stomatal conductance and chlorophyll content. Our results indicated that sweet corn growth and yield in the organic plots was significantly higher than those in the conventional plots.

Buffering of recovery from acidification by organic acids

In the United Kingdom, as in other regions of Europe and North America, recent decreases in surface water sulphate concentrations, due to reduced sulphur emissions, have coincided with marked increases in dissolved organic carbon (DOC) concentrations. Since many of the compounds comprising DOC are acidic, the resulting increases in organic acidity may have the potential to offset the benefits of a decrease in mineral (sulphate) acidity. To test this, we used a triprotic model of organic acid dissociation to estimate the proportional organic acid buffering of reduced mineral acidity as measured in the 22 lakes and streams monitored by the UK Acid Waters Monitoring Network. For an average non-marine sulphate decrease of 30 μeq l− 1 over 15 years from 1988–2003, we estimate that around 28% was counterbalanced by rising strong organic acids, 20% by rising alkalinity (partly attributable to an increase in weak organic acids), 11% by falling inorganic aluminium and 41% by falling non-marine base cations. The situation is complicated by a concurrent decrease in marine ion concentrations, and the impact this may have had on both DOC and acidity, but results clearly demonstrate that organic acid increases have substantially limited the amount of recovery from acidification (in terms of rising alkalinity and falling aluminium) that have resulted from reducing sulphur emissions. The consistency and magnitude of sulphate and organic acid changes are consistent with a causal link between the two, possibly due to the effects of changing acidity, ionic strength and aluminium concentrations on organic matter solubility. If this is the case, then organic acids can be considered effective but partial buffers to acidity change in organic soils, and this mechanism needs to be considered in assessing and modelling recovery from acidification, and in defining realistic reference conditions. However, large spatial variations in the relative magnitude of organic acid and sulphate changes, notably for low-deposition sites in northwestern areas where organic acid increases apparently exceed non-marine sulphate decreases, suggest that additional factors, such as changes in sea-salt deposition and climatic factors, may be required to explain the full magnitude of DOC increases in UK surface waters.

Geoarchaeological investigations of midden-formation processes in the early to late Neolithic levels at Catalhoyuk, Turkey ca. 8550-8370 cal BP.

Anthropogenic midden deposits are remarkably well preserved at the Neolithic settlement of atalhöyük and provide significant archaeological information on the types and nature of activities occurring at the site. To decipher their complex stratigraphy and to investigate formation processes, a combination of geoarchaeological techniques was used. Deposits were investigated from the early ceramic to late Neolithic levels, targeting continuous sequences to examine high resolution and broader scale changes in deposition. Thin-section micromorphology combined with targeted phytolith and geochemical analyses indicates they are composed of a diverse range of ashes and other charred and siliceous plant materials, with inputs of decayed plants and organic matter, fecal waste, and sedimentary aggregates, each with diverse depositional pathways. Activities identified include in situ burning, with a range of different fuel types that may be associated with different activities. The complexity and heterogeneity of the midden deposits, and thus the necessity of employing an integrated microstratigraphic approach is demonstrated, as a prerequisite for cultural and palaeoenvironmental reconstructions.

Rapid changes in the redox conditions of the western Tethys Ocean during the early Aptian oceanic anoxic event

The early Aptian (125 to 121 Ma) records an episode of severe environmental change including a major perturbation of the carbon cycle, an oceanic anoxic event (OAE 1a, 122.5 Ma), a platform drowning episode and a biocalcification crisis. We propose to trace changes in the oxygenation state of the ocean during the early Aptian anoxic event using the redox-sensitive trace-element (RSTE) distribution, phosphorus accumulation rates (PARs) and organic-matter characterization in three different basins of the western Tethys. The following sections have been investigated: Gorgo a Cerbara (central Italy) in the Umbria Marche basin, Glaise (SE France) in the Vocontian basin and Cassis/La Bédoule (SE France) located in the Provencal basin. In the Gorgo a Cerbara section, RSTE distributions show a low background level along the main part of the section, contrasted by different maxima in concentrations within the Selli level. In the Glaise section, the Goguel level displays a weak increase in RSTE contents coeval with moderate TOC values. At Cassis/La Bédoule, no significant RSTE enrichments have been observed in sediments equivalent to the Selli level. These differences in the records of the geochemical proxies of the Selli level or its equivalent indicate the deposition under different redox conditions, probably related to the paleogeography. Our data indicate the development of anoxic–euxinic conditions in the deeper part of the Tethys during OAE 1a, whereas in the shallower environments, conditions were less reducing. Moreover, at Gorgo a Cerbara, the Selli level is characterized by rapid changes in the intensity of reducing conditions in the water column. Ocean eutrophication seems to be a major factor in the development and the persistence of anoxia as suggested by the PAR evolution. Higher PAR values at the onset of OAE 1a suggest an increase in nutrient input, whereas the return to lower values through the first part of the OAE 1a interval may be related to the weakened capacity to retain P in the sedimentary reservoir due to bottom-water oxygen depletion. This general pattern is contrasted by the data of Gorgo a Cerbara, where the sediments deposited during the OAE 1a interval show P-enrichments (mainly authigenic P). This is associated with maxima in TOC values and Corg:Ptot ratios, suggesting that a part of the remobilized P was trapped in the sediments and as such prevented from returning to the water column.

Genotoxicity and composition of particulate matter from biomass burning in the eastern Brazilian Amazon region

In the present study Tradescantia pallida micronucleus (Trad-MCN) bioassay was used to assess the genotoxicity of particulate matter with a mass median aerodynamic diameter less than 10 pm (PM(10)) in Tangara da Serra (MT), a Brazilian Amazon region that suffers the impact of biomass burning. The levels of PM (coarse and fine size fractions) and black carbon (BC) collected were also measured. Furthermore, the alkanes and polycyclic aromatic hydrocarbons (PAHs) were identified and quantified in the samples taken during the burning period by gas chromatography with flame ionization detection (GC-FID). The PM and BC results for both fractions indicate a strong correlation (p < 0.001). The analysis of alkanes indicates an anthropic influence. Retene was the most abundant PAH found, an indicator of biomass burning, and 12 other PAHs considered to be potentially mutagenic and/or carcinogenic were identified in this sample. The Trad-MCN bioassay showed a significant increase in micronucleus frequency during the period of most intense burning, possibly related to the mutagenic PAHs that were found in such extracts. This study demonstrated that Trad-MCN was sensitive and efficient in evaluating the genotoxicity of organic compounds from biomass burning. It further emphasizes the importance of performing chemical analysis, because changes in chemical composition generally have a negative effect on many living organisms. This bioassay (ex situ), using T. pallida with chemical analysis, is thus recommended for characterizing the genotoxicity of air pollution. Crown Copyright (C) 2011 Published by Elsevier Inc. All rights reserved.

Holocene fires in East Amazonia (Caraja`s), new evidences, chronology and relation with paleoclimate

Past studies have evidenced the presence of charcoal in soils and lacustrine sediments of Amazonia region and suggested occurrences of widespread fires during the Middle Holocene. However, the available records do not indicate the changes in fire regime with enough time resolution. We quantified charcoal fragments in lacustrine sediments in a lake of North Carajas plateau in East Amazonia (5 degrees 50`-6 degrees 35`S and 49 degrees 30`-52 degrees 00`W). The charcoal quantification was compared to other sediment proxies, allowing a connection between paleofires and climate changes. Large variations in sediment characteristics led to distinct stages of sedimentation. From 11,800 (base of CSN 93/4) to 4750 cal yr B.P., low accumulation rates of organic matter are observed. Between 7600 cal yr B.P. (base of CSN 93/3 core) and 4750 cal yr B.P., this initial phase of sedimentation is characterized by low chlorophyll derivate accumulation rates and high accumulation rates of Botryococcus braunii, an alga resistant to episodic drought. The first phase of sedimentation would therefore correspond to, a low take level and a drier climate than today. Large biomass burning events occurred between 7450 cal yr B.P. and 4750 cal yr B.P., as indicated by the high charcoal particle concentration. From 4750 cal yr B.P. to 2800 cal yr B.P., accumulation rates of charcoal particles decreased, and the accumulation rate of chlorophyll derivate was low. From 2800 cal yr B.P. to 1300 cal yr B.P., the charcoal accumulation rates reached their lowest values in the core and a rapid increase in lacustrine production is evidenced by the increase in chlorophyll derivates and carbon accumulation rate. From 1300 cal yr B.P. to the last century, the charcoal accumulation rates increased. During the most recent period, the record is characterized by high accumulation rates of chlorophyll derivates while the charcoal particle accumulation rate decreased. This region is still unaffected by the current increase of anthropogenic fires. (c) 2007 Elsevier B.V. All rights reserved.

Evaluation of some metals in Brazilian coffees cultivated during the process of conversion from conventional to organic agriculture

The aim of this study was to evaluate the presence of nutrients and toxic elements in coffees cultivated during the process of conversion, on organic agriculture, in southwest Bahia, Brazil. Levels of the nutrients and toxic elements were determined in samples of soils and coffee tissues from two transitional organic farms by atomic absorption spectrometry (FAAS). The metals in soil samples were extracted by Mehlich1 and USEPA-3050 procedures. Coffee samples from both farms presented relatively high levels of Cd, Zn and Cu (0.75,45.4 and 14.9 mu g g(-1). respectively), but were still below the limits specified by the Brazilian Food Legislation. The application of statistical methods showed that this finding can be attributed to the addition of high amounts of organic matter during the flowering tree period which can act on the bioavailability of metal ions in soils. (C) 2009 Elsevier Ltd. All rights reserved.

Mutagenicity and DNA adduct formation of PAH, nitro-PAH, and oxy-PAH fractions of atmospheric particulate matter from Sao Paulo, Brazil

Urban particulate matter (UPM) contributes to lung cancer incidence. Here, we have studied the mutagenic activity and DNA adduct-forming ability of fractionated UPM extractable organic matter (EOM). UPM was collected with a high-volume sampler in June 2004 at two sites, one at street level adjacent to a roadway and the other inside a park within the urban area of the city of Sao Paulo, Brazil. UPM was extracted using dichloromethane, and the resulting EOM was separated by HPLC to obtain PAH, nitro-PAH, and oxy-PAH fractions which were tested for mutagenicity with the Salmonella strains TA98 and YG1041 with and without S9 metabolic activation. The PAH fraction from both sites showed negligible mutagenic activity in both strains. The highest mutagenic activity was found for the nitro-PAH fraction using YG1041 without metabolic activation; however, results were comparable for both sites. The nitro-PAH and oxy-PAH fractions were incubated with calf thymus DNA under reductive conditions appropriate for the activation of nitro aromatic compounds, then DNA adduct patterns and levels were determined with thin-layer chromatography (TLC) (32)p-postlabeling method using two enrichment procedures-nuclease PI digestion and butanol extraction. Reductively activated fractions from both sites produced diagonal radioactive zones (DRZ) of putative aromatic DNA adducts on thin layer plates with both enrichment procedures. No such DRZ were observed in control experiments using fractions from unexposed filters or from incubations without activating system. Total adduct levels produced by the nitro-PAH fractions were similar for both sites ranging from 30 to 45 adducts per 10(8) normal nucleotides. In contrast, the DNA binding of reductively activated oxy-PAH fractions was three times higher and the adduct pattern consisted of multiple discrete spots along the diagonal line on the thin layer plates. However, DNA adduct levels were not significantly different between the sampling sites. Both samples presented the same levels of mutagenic activity. The response in the Salmonella assay was typical of nitroaromatics. Although, more mutagenic activity was related to the nitro-PAH fraction in the Salmonella assay, the oxy-PAH fractions showed the highest DNA adduct levels. More studies are needed to elucidate the nature of the genotoxicants occurring in Sao Paulo atmospheric samples. (C) 2008 Elsevier B.V. All rights reserved.

Retrievals of a size parameter for phytoplankton and spectral light absorption by colored detrital matter from water-leaving radiances at SeaWiFS channels in a continental shelf region off Brazil

Many efforts are currently oriented toward extracting more information from ocean color than the chlorophyll a concentration. Among biological parameters potentially accessible from space, estimates of phytoplankton cell size and light absorption by colored detrital matter (CDM) would lead to an indirect assessment of major components of the organic carbon pool in the ocean, which would benefit oceanic carbon budget models. We present here 2 procedures to retrieve simultaneously from ocean color measurements in a limited number of bands, magnitudes, and spectral shapes for both light absorption by CDM and phytoplankton, along with a size parameter for phytoplankton. The performance of the 2 procedures was evaluated using different data sets that correspond to increasing uncertainties: ( 1) measured absorption coefficients of phytoplankton, particulate detritus, and colored dissolved organic matter ( CDOM) and measured chlorophyll a concentrations and ( 2) SeaWiFS upwelling radiance measurements and chlorophyll a concentrations estimated from global algorithms. In situ data were acquired during 3 cruises, differing by their relative proportions in CDM and phytoplankton, over a continental shelf off Brazil. No local information was introduced in either procedure, to make them more generally applicable. Over the study area, the absorption coefficient of CDM at 443 nm was retrieved from SeaWiFS radiances with a relative root mean square error (RMSE) of 33%, and phytoplankton light absorption coefficients in SeaWiFS bands ( from 412 to 510 nm) were retrieved with RMSEs between 28% and 33%. These results are comparable to or better than those obtained by 3 published models. In addition, a size parameter of phytoplankton and the spectral slope of CDM absorption were retrieved with RMSEs of 17% and 22%, respectively. If these methods are applied at a regional scale, the performances could be substantially improved by locally tuning some empirical relationships.

Influence of organic-mineral fertilization of an oxisol on soil chemical properties and Bracharia brizantha production

A utilização de fertilizante organomineral da indústria produtora dos aminoácidos lisina e treonina pode melhorar a fertilidade de solos tropicais. O presente trabalho teve como objetivo avaliar a influência de diferentes dosagens do fertilizante organomineral denominado Ajifer L-14 nos atributos químicos e no aumento de produção de forragem de um Latossolo Vermelho do noroeste paulista. O delineamento utilizado foi em blocos casualizados, com sete tratamentos e quatro repetições. Os tratamentos foram: T1- testemunha (sem aplicação de Ajifer L-14); T2- testemunha com vegetação natural; T3- adubação mineral de acordo com a necessidade da cultura e a análise do solo (usando 1,35 kg de ureia, 2,20 kg de superfosfato simples e 0,51 kg de KCl por parcela, o que corresponde a 60 kg de N, 40 kg de P2O5 e 30 kg ha-1 de K2O, respectivamente); T4- adubação com Ajifer L-14 de acordo com a recomendação da análise química do solo (40 L parcela-1, o que corresponde a 60 kg ha-1 N); T5- adubação com Ajifer L-14 em dosagem 50 % acima da recomendação (60 L parcela-1, o que corresponde a 90 kg ha-1 N; T6- adubação com Ajifer L-14 em dosagem 50 % abaixo da recomendação (20 L parcela-1, o que corresponde a 30 kg ha-1 N); T7- adubação com Ajifer L-14 em dosagem 25 % acima da recomendação (50 L parcela-1, o que corresponde a 75 kg ha-1 N); e T8- adubação com Ajifer L-14 em dosagem 25 % abaixo da recomendação (30 L parcela-1, o que corresponde a 45 kg ha-1 N). Nas profundidades de 0,0-0,1 e 0,1-0,2 m, avaliaram-se os seguintes atributos químicos do solo:, teor de matéria orgânica (MO), pH, K+, Ca2+, Mg2+, capacidade de troca catiônica (CTC), acidez potencial e saturação por bases. A aplicação do fertilizante organomineral não influenciou os atributos químicos do solo. Na análise de regressão, houve relação polinomial entre as doses de aplicação do fertilizante organomineral e a produção de massa seca e proteína bruta de Bracharia brizantha.

Macrofauna de ambientes não consolidados adjacentes à recifes da área de proteção ambiental dos recifes de corais Rio Grande do Norte, Brasil

This study aimed to characterize, for the first time, the benthic invertebrates that inhabit the region of soft bottoms adjacent to the APARC reefs in order to situate them as an important component of infralittoral coastal areas of Northeast Brazil. Soft bottoms areas of APARC corresponds to infralittoral zones vegetated by seagrass Halodule wrightii and unvegetated infralittoral zones, both subjected to substantial hydrodynamic stress. Through scuba diving, biological and sedimentary samples of both habitats were analyzed, with a cylindrical sampler. We identified 6160 individuals belonging to 16 groups and 224 species. The most abundant macrofaunal group was Polychaeta (43%), followed by Mollusca (25%) and Crustacea (14%), what was expected for these environments. In the first chapter, regarding vegetated areas, we tested three hypotheses: the existence of differences in the faunal structure associated with H. wrightii banks submitted to different hydrodynamic conditions; the occurrence of minor temporal variations on the associated macrofauna of banks protected from hydrodynamic stress; and if the diversity of macrofauna is affected by both benthophagous predators and H. wrightii biomass. It was observed that macrofauna associated at the Exposed bank showed differences in structure when comparing the Protected bank, the granulometry of the sediments, that co-varies with the hydrodynamism, was the cause of these variations. The results also pointed to a lower temporal variation in the macrofaunal structure on the Protected bank and a negative relation between macrofaunal and benthophagous fish abundance. At the Exposed bank, a greater faunal diversity was observed, probably due to the higher seagrass biomass. The second chapter compares the vegetated and non-vegetated areas in order to test the hypothesis that due to greater seasonal stability in tropical environments, seagrass structure would act to distinguish the vegetated and non-vegetated areas macrofauna, over time. It was also expected that depositivores were the most representative invertebrates on non-vegetated environments, on the assumption that the seagrass bank would work as a source of debris to adjacent areas, enriching them. Considering all sampling periods, the total macrofauna abundance and diversity were higher in vegetated areas, when compared to non-vegetated ones. Seasonally, the structural complexity provided by Halodule differentiated more clearly the fauna from vegetated and non-vegetated areas, but only at the climatic extremes, i.e. Dry season (extreme climatic stability, with low hydronamism variation) and Rainy season (great hydrodynamism variation and probably vegetated bank burial). Furthermore, the high organic matter levels measured in the sandy banks coincided with an outstanding trophic importance of deposit feeders, proving the debris-carrying hypothesis. The last chapter focused on the non-vegetated areas, where we tested that the hypothesis infaunal halo in tropical reefs depending on local granulometry. In this context, we also tested the hypothesis that benthophagous fish predation would have an effect on the low abundance of macrofaunal groups due to the high hydrographic stress, thus allowing other predatory groups to have greater importance in these environments. Proving the hypothesis, no spatial variation, both on abundance families neither on community structure, occur along distance of the edge reefs. However, we found that complex combinations of physical factors (grain size and organic matter levels originated from local hydronamic conditions) covary with the distance from the reefs and has stronger influence on macrofauna than considered biological factors, such as predation by benthophagous fishes. Based on the main results, this study shows that unconsolidated areas around APARC reefs are noteworthy from an ecological and conservational point of view, as evidenced by the biota-environment and organismal relations, never before described for these areas

Evaluation of organic molecules originated during composting process

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Organic complexation and translocation of ferric iron in podzols of the Negro River watershed. Separation of secondary Fe species from Al species

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