Analysis of accumulation,extractability, and metabolization of five different phenylarsenic compounds in plants by ion chromatography with mass spectrometric detection and by atomic emission spectroscopy

Phenylated arsenic compounds occur as highly toxic contaminants in former military areas where they were formed as degradation products of chemical warfare agents. Some phenylarsenic compounds such as roxarsone and aminophenylarsonic acids were applied as food additive and veterinary drugs in stock-breeding and therefore pose an environmental risk in agricultural used sites. Very few data exist in the literature concerning uptake and effects of phenylarsenic compounds in plants growing on contaminated soils. In this study, the accumulation, extractability, and metabolization of five different phenylarsenic compounds, phenylarsonic acid, p- and o-aminophenylarsonic acid, phenylarsine oxide, and 3-nitro-4-hydroxyphenylarsonic acid called roxarsone, by the terrestrial plant Tropaeolum majus were investigated. Ion chromatography coupled to inductively coupled plasma mass spectrometry was used to differentiate these arsenic compounds, and inductively coupled plasma atomic emission spectroscopy was used for total arsenic quantification. All compounds considered were taken up by the roots and transferred to stalks, leaves, and flowers. The strongest accumulation was observed for unsubstituted phenylarsonic acid followed by its trivalent analogue phenylarsine oxide that was mostly oxidized in soil whereas the amino- or nitro- and hydroxy-substituted phenylarsonic acids were accumulated to a smaller degree.The highest extraction yield of 90% for ground leaf material was achieved by 0.1 M phosphate buffer, pH 7.7, in a two-step extraction with a total extraction time of 24 h. The extraction of higher amounts of arsenic (50–70% of total arsenic present in leaves depending on arsenic species application) from non-ground intact leaves with deionized water in comparison with the buffer (20–40% of total arsenic) is ascribed to osmotic effects. The arsenic species analysis revealed a cleavage of the amino groups from the phenyl ring for plants treated with aminophenylarsonic acids. A further important metabolic effect consisted in the production of inorganic arsenate and arsenite from the phenylated arsonic acid groups.     

Analysis of accumulation, extractability, and metabolization of five different phenylarsenic compounds in plants by ion chromatography with mass spectrometric detection and by atomic emission spectroscopy

Phenylated arsenic compounds occur as highly toxic contaminants in former military areas where they were formed as degradation products of chemical warfare agents. Some phenylarsenic compounds such as roxarsone and aminophenylarsonic acids were applied as food additive and veterinary drugs in stock-breeding and therefore pose an environmental risk in agricultural used sites. Very few data exist in the literature concerning uptake and effects of phenylarsenic compounds in plants growing on contaminated soils. In this study, the accumulation, extractability, and metabolization of five different phenylarsenic compounds, phenylarsonic acid, p- and o-aminophenylarsonic acid, phenylarsine oxide, and 3-nitro-4-hydroxyphenylarsonic acid called roxarsone, by the terrestrial plant Tropaeolum majus were investigated. Ion chromatography coupled to inductively coupled plasma mass spectrometry was used to differentiate these arsenic compounds, and inductively coupled plasma atomic emission spectroscopy was used for total arsenic quantification. All compounds considered were taken up by the roots and transferred to stalks, leaves, and flowers. The strongest accumulation was observed for unsubstituted phenylarsonic acid followed by its trivalent analogue phenylarsine oxide that was mostly oxidized in soil whereas the amino- or nitro- and hydroxy-substituted phenylarsonic acids were accumulated to a smaller degree.The highest extraction yield of 90% for ground leaf material was achieved by 0.1 M phosphate buffer, pH 7.7, in a two-step extraction with a total extraction time of 24 h. The extraction of higher amounts of arsenic (50–70% of total arsenic present in leaves depending on arsenic species application) from non-ground intact leaves with deionized water in comparison with the buffer (20–40% of total arsenic) is ascribed to osmotic effects. The arsenic species analysis revealed a cleavage of the amino groups from the phenyl ring for plants treated with aminophenylarsonic acids. A further important metabolic effect consisted in the production of inorganic arsenate and arsenite from the phenylated arsonic acid groups.     

Adsorption and photocatalytic decomposition of roxarsone by TiO2 and its mechanism

Roxarsone (3-nitro-4-hydroxyphenylarsonic acid) has been widely used as organic arsenic additive in animal industry. In this study, the adsorption of roxarsone on TiO₂ under dark conditions, the photocatalytic decomposition of roxarsone under UV/TiO₂, and the possible photocatalytic pathway were investigated. At the initial concentration of 5–35 mg/L, the adsorption of roxarsone fitted well with the pseudo-second-order kinetics. The isotherms analysis showed that the Langmuir model was better than the Freundlich and Dubinin–Radushkevich models for describing the adsorption process. After 7 h of photocatalytic decomposition, a complete disappearance of roxarsone was achieved. The pH value has a significant effect on both adsorption and photocatalytic decomposition of roxarsone. The results of high-performance liquid chromatography-hydride generation-atomic fluorescence spectrometry (HPLC-HG-AFS) and gas chromatography-mass spectrometry (GC/MS) analyses proved the cleavage of the As-C bond during the photocatalytic decomposition process by TiO₂ and the intermediates of the decomposition. Based on the results, a possible photocatalytic decomposition pathway was proposed.     

Fate of arsenic compounds in poultry litter upon land application

The use of the organic As compound, roxarsone, as an antibiotic additive to poultry feed continues to raise concern over potential negative environmental impacts. Total As concentration in poultry litter can reach >40 mg kg⁻¹ and both roxarsone and its mineralization product As(V) have been identified in poultry litters (PL). To investigate the fate of these As species upon land application of PL we conducted two studies. In the first, an Orangeburg soil (Ultisol from the Atlantic Coastal Plain) was spiked with either 20 mg kg⁻¹ As(V) or roxarsone and incubated at 10% moisture content for 4 months. Exchangeable As was determined periodically by extraction with 0.1 M PO₄. Both As(V) and roxarsone displayed similar desorption; initially, approximately 70% of added As was ligand exchangeable and this decreased to 35% after 4 months incubation, presumably due to either slow sorption reactions or a change in solid phase speciation of As to less exchangeable forms. In the second study, various manipulations of two PL samples were applied to the Orangeburg soil at realistic field application rates. The treatments were wet to 10% moisture content and water soluble As, Cu and organic carbon (DOC) was measured over 30 days. Arsenic and Cu solubility were highest from the dried litter samples. Ashing of the PLs decreased soluble As and Cu, presumably because of the loss of organic matter from the ashed litter and subsequent decrease in DOC. Application of leachates from either PL resulted in higher concentrations of soluble As and Cu than when the soil was amended with equivalent concentrations of soluble As and Cu dissolved in DI H₂O. We hypothesize that the increased levels of DOC from the PL treatments enhance As and Cu solubility through competitive sorption and complexation, respectively. In fact, As and Cu solubility was correlated to DOC levels in the amended soil extracts. Even though land application of PL introduced relatively low concentrations of As and Cu to soil it appeared that other soluble constituents of PL significantly enhanced As and Cu solubility.     

Occurrence of steroid hormones and antibiotics in shallow groundwater impacted by livestock waste control facilities

Wastewater impoundments at concentrated animal feeding operations (CAFOs) represent a potential source of veterinary pharmaceuticals and steroid hormone contamination to shallow groundwater. This study investigates the occurrence of seventeen veterinary pharmaceuticals and thirteen steroid hormones and hormone metabolites in lagoons and adjacent groundwater at operating swine and beef cattle facilities. These sites were chosen because subsurface geology and previous monitoring of nitrate, ammonia and chloride levels in shallow ground water strongly indicated direct infiltration, and as such represent worst cases for ground water contamination by waste water. Pharmaceutical compounds detected in samples obtained from cattle facilities include sulfamerazine; sulfamethazine; erythromycin; monensin; tiamulin; and sulfathiazole. Lincomycin; ractopamine; sulfamethazine; sulfathiazole; erythromycin; tiamulin and sulfadimethoxine were detected in wastewater samples obtained from swine facilities. Steroid hormones were detected less frequently than veterinary pharmaceuticals in this study. Estrone, testosterone, 4-androstenedione, and androsterone were detected in wastewater impoundments at concentrations ranging from 30 to 3600ng/L, while only estrone and testosterone were detected in groundwater samples at concentrations up to 390ng/L. The co-occurrence of veterinary pharmaceutical and steroid hormone contamination in groundwater at these locations and the correlation between pharmaceutical occurrence in lagoon wastewater and hydraulically downgradient groundwater indicates that groundwater underlying some livestock wastewater impoundments is susceptible to contamination by veterinary pharmaceuticals and steroid hormones originating in wastewater lagoons.     

铜绿假单胞菌GF31降解土壤中氯氰菊酯的性能研究

利用实验室分离获得铜绿假单胞菌GF31(Pseudomonas aeruginosa GF31,简称菌株GF31),采用气相色谱/质谱联用(GC/MS)分析技术,开展菌株GF31在实际土壤环境中对氯氰菊酯的降解特性和降解产物研究,并进行了模拟田间实验.结果表明,在土壤中菌株GF31降解氯氰菊酯的主要产物为二氯菊酸和间苯...     

EDTA-enhanced extraction of heavy metals from a coarse grained simulated soil by the CEHIXM process

The effect of ethylenediaminetetraacetic acid (EDTA) in extracting heavy metal contaminants, namely Pb, Cd, Zn, and Mn, from soils with organometallic complexes, was explored using the coupled electric-hydraulic gradient assisted by ion exchange medium (CEHIXM) decontamination process. The experiments were conducted with a constant electric voltage of 50 DC V and a constant hydraulic flow rate of 4 cm3/min. The results obtained from the experiments demonstrated that EDTA was effective in extracting Pb, Cd, Zn, and Mn from soils in which acidic pH did not produce significant dissolution. Metal removal as high as 99% was achieved with 0.05 M EDTA solution within 200 hr.     

Photodegradation of new amino acid derivatives suitable for chelating agents in pulp bleaching applications

The purpose of this study was to evaluate photodegradabilities of the following new low-nitrogen chelating agents: N-bis[(carboxymethoxy)ethyl]glycine (compound 1), N-bis[(1,2-dicarboxyethoxy)ethyl]glycine (compound 2) and N-bis[(1,2-dicarboxyethoxy)ethyl]aspartic acid (compound 3). At first photodegradation of these chelating agents as uncomplexed Na-compound 1–3 and Cu(II) complexes were tested, both in lake and distilled water, by exposing them to near-UV region radiation at the range of 315–400 nm. Uncomplexed Na-compounds 2 and 3 were selected to sunlight exposure experiments carried out in lake and distilled water. Compound 3 was also tested in sunlight as Cu and Ca complexes in both solutions. Photodegradation of Na₆-compound 3 in distilled water was studied by exposing it to radiation at the wavelength of 253.7 nm. Photodegradation products were analysed by means of GC-MS (gas chromatography with mass selective detector).

The results demonstrated that compound 1 was quite photostable even as Cu complex while compounds 2 and 3 were found to be photodegradable. Over 90% reduction of compound 3 was achieved during one week and 80% reduction of compound 2 in two weeks' time when they were added as Na salt to lake water and exposed to sunlight. Compound 3 as Cu complex degraded totally in the sunlight in less than one week. In the case of compound 3, the degradation rate decreased depending on the counter cation in the order Cu > Na  Ca. The study demonstrated that photodegradation of Na₆-compound 3 does not result in total mineralization of the compound. A photodegradation pathway for Na₆-compound 3 is proposed.     

Reduction of pharmaceutically active compounds by a lagoon wetland wastewater treatment system in Southeast Louisiana

A number of pharmaceutically active compounds (PhACs) have been detected in the aquatic environment as a result of discharges of municipal wastewater. In the state of Louisiana, USA, many municipalities treat wastewater using natural systems, such as lagoons and wetlands, rather than conventional wastewater treatment technologies. Nearly all research to date has focused on the fate of PhACs in conventional treatment plants, not constructed and natural wetlands. In the wastewater treatment plant (WWTP) for Mandeville, Louisiana, USA, wastewater flows of 7600 m³ d⁻¹ are treated in a series of aeration lagoons (basins), followed by a constructed wetland and UV disinfection, before being discharged into a natural forested wetland (i.e. Bayou Chinchuba) and eventually, Lake Pontchartrain. Thirteen out of the 15 PhACs investigated were detected in the wastewater inflow to the treatment plant. Only 9 of the 13 compounds were above the detection limits at the treatment plant effluent. The concentrations of most compounds were reduced by greater than 90% within the plant, while carbamazepine and sotalol were only reduced by 51% and 82%, respectively. The percent reductions observed in the Mandeville system were greater than reduction rates reported for conventional WWTPs; perhaps due to the longer treatment time (∼30 days). Most target PhACs were not completely removed before discharge into Lake Pontchartrain, although their collective annual loading was reduced to less than 1 kg and down to ppb with significant potential for dilution in the large lake.     

Free Fatty acids and sterols in swine manure

Free fatty acids and sterols were assessed in fresh manure and anaerobic lagoon sludge from swine production facilities in North Carolina. Eight free fatty acids and five sterols were identified and quantified in both manure and sludge samples. Compound identification was performed by gas chromatography/mass spectroscopy (GC-MS), and compound quantities were determined by gas chromatography after solid phase extraction with a 50:50 mixture of diethyl ether and hexane. The free fatty acids occurring in greatest abundance in both fresh manure and lagoon sludge were palmitic, oleic, and stearic. Free fatty acid content in fresh manure ranged from approximately 3 microg g(-1) dry weight (dw) to over 45 microg g(-1) dw. In lagoon sludge, free fatty acid content ranged from about 0.8 microg g(-1) dw to nearly 4 microg g(-1) dw. Coprostanol and epicoprostanol were the sterols in largest concentrations in fresh manure and lagoon sludge samples. Total sterol content ranged from approximately 0.5 microg g(-1) dw to around 11 microg g(-1) dw in fresh manure and from 3.5 microg g(-1) dw to almost 9 microg g(-1) dw in lagoon sludge. Fresh manure and lagoon sludge both had high levels of inorganic cations (e.g., Ca, Mg, Fe) capable of binding free fatty acids and forming insoluble complexes, thereby potentially reducing fatty acid biodegradation. In anaerobic lagoons, sterols are an organic fraction of sludge that are resistant to bacterial degradation. In the case of fresh manure, fatty acids could represent a potential source of energy via the manufacture of biodiesel fuel, if efficient means for their extraction and transesterification can be devised.     

Nontarget analysis of polar contaminants in freshwater sediments influenced by pharmaceutical industry using ultra-high-pressure liquid chromatography-quadrupole time-of-flight mass spectrometry

A comprehensive analytical procedure for a reliable identification of nontarget polar contaminants in aquatic sediments was developed, based on the application of ultra-high-pressure liquid chromatography (UHPLC) coupled to hybrid quadrupole time-of-flight mass spectrometry (QTOFMS). The procedure was applied for the analysis of freshwater sediment that was highly impacted by wastewater discharges from the pharmaceutical industry. A number of different contaminants were successfully identified owing to the high mass accuracy of the QTOFMS system, used in combination with high chromatographic resolution of UHPLC. The major compounds, identified in investigated sediment, included a series of polypropylene glycols (n = 3-16), alkylbenzene sulfonate and benzalkonium surfactants as well as a number of various pharmaceuticals (chlorthalidone, warfarin, terbinafine, torsemide, zolpidem and macrolide antibiotics). The particular advantage of the applied technique is its capability to detect less known pharmaceutical intermediates and/or transformation products, which have not been previously reported in freshwater sediments.     

Reduction of pharmaceutically active compounds by a lagoon wetland wastewater treatment system in Southeast Louisiana

A number of pharmaceutically active compounds (PhACs) have been detected in the aquatic environment as a result of discharges of municipal wastewater. In the state of Louisiana, USA, many municipalities treat wastewater using natural systems, such as lagoons and wetlands, rather than conventional wastewater treatment technologies. Nearly all research to date has focused on the fate of PhACs in conventional treatment plants, not constructed and natural wetlands. In the wastewater treatment plant (WWTP) for Mandeville, Louisiana, USA, wastewater flows of 7600 m³ d⁻¹ are treated in a series of aeration lagoons (basins), followed by a constructed wetland and UV disinfection, before being discharged into a natural forested wetland (i.e. Bayou Chinchuba) and eventually, Lake Pontchartrain. Thirteen out of the 15 PhACs investigated were detected in the wastewater inflow to the treatment plant. Only 9 of the 13 compounds were above the detection limits at the treatment plant effluent. The concentrations of most compounds were reduced by greater than 90% within the plant, while carbamazepine and sotalol were only reduced by 51% and 82%, respectively. The percent reductions observed in the Mandeville system were greater than reduction rates reported for conventional WWTPs; perhaps due to the longer treatment time (30 days). Most target PhACs were not completely removed before discharge into Lake Pontchartrain, although their collective annual loading was reduced to less than 1 kg and down to ppb with significant potential for dilution in the large lake.     

Effects of organic matter on the distribution of uranium in soil and plant matrices

This work studied interactions of uranium with pure organic compounds, such as glutathione, and more complex mixtures, such as humic acid and aqueous plant extracts. High performance liquid chromatography with UV absorption interfaced to inductively coupled plasma mass spectrometry sequential detection was used to detect organouranium complexes in a variety of soils and plant materials, indicating that nearly 100% of the uranium extracted from certain plant tissues was bound to organic ligands. In addition, soil sorption experiments indicated that humic acid generally decreased uranium sorption to soils and promoted subsequent desorption of uranium because of uranium partitioning to the organic phase. These experiments demonstrate that organic compounds influence the mobility and chemistry of uranium in the environment.     

Copper complexation by tannic acid in aqueous solution

The speciation of titrated copper in a dissolved tannic acid (TA) solution with an initial concentration of 4 mmol organic carbon (OC)/l was investigated in a nine-step titration experiment (Cu/OC molar ratio = 0.0030–0.0567). We differentiated between soluble and insoluble Cu species by 0.45 μm filtration. Measurements with a copper ion selective electrode (ISE) and diffusive gradients in thin films (DGT) were conducted to quantify unbound Cu(II) cations (‘free’ Cu) and labile soluble Cu complexes. For the DGT measurements, we used an APA hydrogel and a Chelex 100 chelating resin (Na form). Insoluble organic Cu complexes (>0.45 μm) was the dominant Cu species for Cu/OC = 0.0030–0.0567 with a maximum fraction of 0.96 of total Cu. At Cu/OC > 0.0100, Cu-catalysed degradation of aggregate structures resulted in a strong increase of free Cu and (labile) soluble Cu complexes with a maximum fraction of 0.28 and 0.32 of total Cu, respectively. Labile (i.e. DGT-detectable) soluble Cu complexes had a relatively high averaged diffusion coefficient (D) in the APA hydrogel (3.50 × 10⁻⁶– 5.58 × 10⁻⁶ cm² s⁻¹).     

Uptake of Cd(II) and Pb(II) by microalgae in presence of colloidal organic matter from wastewater treatment plant effluents

The present study addresses the key issue of linking the chemical speciation to the uptake of priority pollutants Cd(II) and Pb(II) in the wastewater treatment plant effluents, with emphasis on the role of the colloidal organic matter (EfOM). Binding of Cd(II) and Pb(II) by EfOM was examined by an ion exchange technique and flow field-flow fractionation coupled to inductively coupled plasma mass spectrometry in parallel to bioassays with green microalga Chlorella kesslerii in ultrafiltrate (<1 kDa) and colloidal isolates (1 kDa to 0.45 μm). The uptake of Cd by C. kesslerii was consistent with the speciation analysis and measured free metal ion concentrations, while Pb uptake was much greater than that expected from the speciation measurement. Better understanding of the differences in the effects of the EfOM on Cd(II) and Pb(II) uptake required to take into account the size dependence of metal binding by EfOM.     

Application of laser ablation ICP-MS and traditional techniques to the study of black crusts on building stones: a new methodological approach

Introduction  

In this work, we propose an innovative application of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) as a methodological approach for the chemical characterisation of black crusts on stone monuments, associated with traditional micro-morphological (optical and scanning electron microscopy) and infrared spectroscopic techniques (FTIR).     

Heavy metals in untreated/treated urban effluent and sludge from a biological wastewater treatment plant

Background, Aim and Scope

The presence of heavy metals in wastewater is one of the main causes of water and soil pollution. The aim of the present study was to investigate the removal of Cd, Cu, Pb, Hg, Mn, Cr and Zn in urban effluent by a biological wastewater treatment, as well as to quantify the levels of As, Be, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sn, Tl, V and Zn in dewatering sludge from the Biological Wastewater Treatment Plant to Ribeirão Preto (RP-BWTP), Brazil.

Materials and Methods

Concentrations of Cd, Cr, Cu, Mn and Pb in wastewater and those of Ni in sludge were determined by atomic absorption spectrophotometry with graphite furnace atomization. Mercury concentrations in wastewater were measured by hydride generation atomic spectrophotometry, and Zn levels were determined by atomic absorption spectrophotometry using acetylene flame. In sludge, the levels of As, Be, Cd, Cr, Cu, Fe, Hg, Mn, Pb, Sn, Tl, V and Zn were determined by inductively coupled plasma-mass spectrometry.

Results

The percentages of removal efficiency (RE) were the following: Hg 61.5%, Cd 60.0%, Zn 44.9%, Cu 44.2%, PB 39.7%, Cr 16,5% and Mn 10.4%. In turn, the mean concentrations (mg/kg) of metals in dewatering sludge followed this increasing order: Tl (<0.03), Hg (0.31), Be (0.43), As (1.14), Cd (1.34), V (59.2), Pb (132.1), Sn (166.1), Cr (195.0), Mn (208.1), Ni (239.4), Cu (391.7), Zn (864.4) and Fe (20537).

Discussion

The relationship between metal levels in untreated wastewater, as well as the removal efficiency are in agreement with previous data from various investigators, It is important to note that metal removal efficiency is not only affected by metal ion species and concentration, but also by other conditions such as operating parameters, physical, chemical, and biological factors.

Conclusions

Metal values recorded for treated wastewater and sludge were within the maximum permitted levels established by the Environmental Sanitation Company (CETESB), São Paulo, Brazil.

Recommendations

There is an urgent need for the authorities who are responsible for legislation on sludge uses in agriculture of establishing safety levels for As, Be, Hg, Sn, Tl and V.

Perspectives

According to the current metal levels, RP-BWTP sludge might be used for agriculture purposes. However, for an environmentally safe use of sewage sludge, further studies including systematic monitoring are recommended. Annual metal concentrations and predicted variations of those elements in the sludge should be monitored.

     

Free Fatty Acids and Sterols in Swine Manure

Free fatty acids and sterols were assessed in fresh manure and anaerobic lagoon sludge from swine production facilities in North Carolina. Eight free fatty acids and five sterols were identified and quantified in both manure and sludge samples. Compound identification was performed by gas chromatography/mass spectroscopy (GC-MS), and compound quantities were determined by gas chromatography after solid phase extraction with a 50:50 mixture of diethyl ether and hexane. The free fatty acids occurring in greatest abundance in both fresh manure and lagoon sludge were palmitic, oleic, and stearic. Free fatty acid content in fresh manure ranged from approximately 3 μ g g^?1 dry weight (dw) to over 45 μ g g^?1 dw. In lagoon sludge, free fatty acid content ranged from about 0.8 μ g g^?1 dw to nearly 4 μ g g^?1 dw. Coprostanol and epicoprostanol were the sterols in largest concentrations in fresh manure and lagoon sludge samples. Total sterol content ranged from approximately 0.5 μ g g^?1 dw to around 11 μ g g^?1 dw in fresh manure and from 3.5 μ g g^?1 dw to almost 9 μ g g^?1 dw in lagoon sludge. Fresh manure and lagoon sludge both had high levels of inorganic cations (e.g., Ca, Mg, Fe) capable of binding free fatty acids and forming insoluble complexes, thereby potentially reducing fatty acid biodegradation. In anaerobic lagoons, sterols are an organic fraction of sludge that are resistant to bacterial degradation. In the case of fresh manure, fatty acids could represent a potential source of energy via the manufacture of biodiesel fuel, if efficient means for their extraction and transesterification can be devised.