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1.
The distribution and bioavailability of Hg in vegetable-growing soils collected from the estuary areas of Jiulong River, China, were studied. Concentrations of Hg in top-soils, soil profiles and plant samples were measured with the method of hydride generation atomic fluorescence spectrometry after microwave digestion. Mercury species in soils were determined with the sequential extraction procedures based on Kingston method. Results showed that Hg concentrations in top-soils ranged from 49.8 to 1,685 ng g?1, with an average of 510 ng g?1 which was more than twice higher than the mercury limit (250 ng g?1 at pH < 6.5) of soil quality set for edible agricultural products in China (HJ 332-2006). High levels of Hg were found to mainly distribute in the top-soils from the northern, western and southern part of the estuary areas. Hg concentrations decreased with the increases of profile depths, except for one sample (S15) in which Hg level in the depth of 0–20 cm was found lower than that in the 20–40 cm. Hg in most of soil samples in non-mobile forms accounted for 46–82 % of total Hg in soils, while Hg in the mobile forms only 0.6–8.7 %. No significant correlation of Hg concentrations between the vegetables and the soils was observed in the studied areas, which indicates that the transfer factors could only reflect the abilities of Hg uptake and accumulation in a specific plant, but they are unsuitable to be used as the general indexes for the mobility and bioavailability of Hg in soils.  相似文献   

2.
The present study fills a gap in the knowledge in regards to the occurrence of banned pesticides at both coastal and inland locations at the Southwest Buenos Aires region, Argentina. Superficial sediment and soil samples were collected from different sites along the Bahia Blanca Estuary and surrounding sites to assess the concentration levels and spatial distribution of 12 selected organochlorine pesticides (OCs); 13 spatial locations including inland and shore-coast were sampled to evaluate occurrence and concentration levels of hexachlorocyclohexanes α-HCH, β-HCH, δ-HCH, γ-HCH, dichlorodiphenyltrichloroethane and its degradation products (DDXs: p,p′-DDT, o,p′-DDT, p,p′-DDE, o,p′-DDE, p,p′-DDD, o,p′-DDD) and the polychlorobenzenes PeCB (pentachlorobenzene) and HCB (hexachlorobenzene). After cleaning and extractions steps, samples were analyzed by means of gas chromatography/mass spectrometry. ∑OCs (sum of all studied compounds) ranged between 0.206 and 1040 ng g?1 dw (mean?=?82.4 and SD?=?277 ng g?1 dw). Total HCHs (sum of α-HCH, β-HCH, γ-HCH and δ-HCH) ranged from 0.0858 to 0.876 ng g?1 dw (mean?=?0.43 and SD?=?0.23 ng g?1 dw), DDXs (sum of p,p′and o,p′ isomers) from 0.080 to 1040 ng g?1 dw (mean?=?81.3 and SD?=?277 ng g?1 dw). Lower concentrations were found for PeCB (mean?=?0.095 and SD 0.17 ng g?1 dw) and HCB (mean?=?0.56 and SD 1.7 ng g?1 dw). Principal component analysis (PCA) permitted the extraction of underlying information about common factors, providing an overview of the distribution of pesticides and allowing the characterization of sites in regards to the major pesticide signature.  相似文献   

3.
The Estero de Urías Lagoon (EUL) is an inner shelf barrier coastal lagoon, located in the Mexican Pacific Coast (SE Gulf of California). It is surrounded by Mazatlán City, one of the most important international tourist areas of Mexico. To provide a comprehensive reassessment of the concentration levels and spatial variability of Hg and 210Pb in the EUL, 40 surface sediment samples were analyzed for several geochemical variables (e.g. grain size distribution, organic matter and reference element concentrations) that could explain the observed variability of Hg and 210Pb. The Hg concentrations ranged from 23 to 214 ng g?1, whereas 210Pb activities varied from 20 to 56 Bq kg?1. No defined distribution pattern was observed for Hg and 210Pb concentrations in the lagoon and no evidence of a common atmospheric delivery route was observed. The sediments from EUL were found contaminated by Hg, and according to international guidelines 48 % of the sampling sites have concentrations that could be harmful to biota.  相似文献   

4.
Our study was based on the recent increase in wastewater pollution and its deleterious effects to the marine ecosystem. Using numerical simulation (DESCAR-3.2 software program), we investigated the orientation and quantification of trace metals in wastewater discharges from permanent and semi-permanent drain outfalls constructed along the Kuwait Coastline encompassing six Kuwait Governorates (GI-GVI). This study was related to trace metals toxicity and bioaccumulation effects on the commercial yellow fin Sea bream, Acanthopagrus latus fish using probit program and bioaccumulation factor (BAF), respectively. Observations from wastewater discharges showed high trace metals concentrations in the sequence of Zn > Cr > Cu > Fe > Ni > Pb > Hg during winter compared to summer and in GI and GIV compared to drain outfalls in the other Governorates. Seasonally, trace metals in A. latus revealed the sequence of Zn > Fe > Cu > Ni > Cr > Pb > Hg in GI, GII and GIV indicating the significance of toxic metals that bioaccumulated from their surrounding untreated wastewater. Toxicity test revealed A. latus highly sensitive to Hg even at low lethal concentrations (LC15) compared to other metals. BAF in A. latus body parts was >1 indicating significant accumulation of trace metals from wastewater. However, BAF was <1 in Cr suggesting that A. latus could absorb trace metals from multiple sources over lengthy exposure period and not necessarily from wastewater containing rich Cr levels. Thus, the present findings validate A. latus as bioindicator to pollution more authentically by numerical simulation, toxicity and bioaccumulation tests compared to the traditional method of labeling A. latus as a pollution indicator.  相似文献   

5.
Multidimensional assessment of air pollution was carried out on trace metals in particulates, desert plant parts and soil collected from the six sites to validate air pollution tolerance index, translocation and bioaccumulation factors. A map indicating the sampled sites was superimposed on the Disper 5.2 software graphical interface to track the particulate dispersion route during the summer and winter seasons. This study showed site-wise orientation of particulates dispersed in the ambient air. Observations indicated the high concentrations of dispersed coarse > fine > ultra-fine particulates in trace metals analyzed from selected desert plants and in the soil especially during winter than in the summer seasons. High air pollution tolerance index was observed in the sequence of Calatropis gigantean > Portulaca oleracea > Citrullus collocynthis > Rumex vesicarius > Bienertia sinuspersici > Tribulus terrestris. Assessment of translocation and bioaccumulation factors labeled these desert plants as hyper-accumulators. The synergistic effect of the translocation and bioaccumulation factor in the various plants and the pollution levels for a given geographical location provides insight management to mitigate air pollution and landscape designers to grow tolerant species and protect sensitive plants from air pollution.  相似文献   

6.
The present work is the first attempt to compare the data of a comprehensive study of the origin and distribution of 16 priority pollutant polycyclic aromatic hydrocarbons (PAHs) in surface sediments (<63 μm) from 18 sampling stations, 9 from Sundarban of Bangladesh and 9 from Indian counterpart. Σ19PAHs concentration in sediments showed wide variations from 208.3 to 12,993.1 ng g?1 dry weight in Indian Sundarban, whereas 208.4 to 4,687.9 ng g?1 in the case of Bangladesh. Fluoranthene, pyrene, benzo(b)fluoranthene, benzo(a)pyrene and dibenzo(a,h)anthracene were predominant species for both the countries. The PAH diagnostic ratios indicated that the PAHs in sediments from both the countries were of mixed source of hydrocarbons of both petrogenic and pyrolytic origin. According to the numerical effect-based sediment quality guidelines, the levels of PAHs in the Sundarban wetland of Bangladesh and India should not exert adverse biological effects. The TEQ values calculated for samples from the Bangladesh and Indian Sundarban varied from 13.68 to 1,014.75 and 1.31 to 2,451 ng g?1 d.w. with an average of 221.02 and 358.63 ng g?1, respectively. The overall contamination status of PAH was higher in India than Bangladesh.  相似文献   

7.
Continuous measurements of speciated atmospheric mercury (Hg), including gaseous elemental mercury (GEM), particulate mercury (PHg), and reactive gaseous mercury (RGM) were conducted in Guizhou Province, southwestern China. Guiyang Power Plant (GPP), Guiyang Wujiang Cement Plant, Guizhou Aluminum Plant (GAP), and Guiyang Forest Park (GFP) in Guiyang were selected as study sites. Automatic Atmospheric Mercury Speciation Analyzers (Tekran 2537A) were used for GEM analysis. PHg and RGM were simultaneously collected by a manual sampling system, including elutriator, coupler/impactor, KCl-coated annular denuder, and a filter holder. Results show that different emission sources dominate different species of Hg. The highest average GEM value was 22.2 ± 28.3 ng·m?3 and the lowest 6.1 ± 3.9 ng·m?3, from samples collected at GPP and GAP, respectively. The maximum average PHg was 1984.9 pg·m?3 and the minimum average 55.9 pg·m?3, also from GPP and GAP, respectively. Similarly, the highest average RGM of 68.8 pg·m?3 was measured at GPP, and the lowest level of 20.5 pg·m?3 was found at GAP. We conclude that coal combustion sources are still playing a key role in GEM; traffic contributes significantly to PHg; and domestic pollution dominates RGM.  相似文献   

8.
Changing global climatic conditions and the continuous eutrophication of aquatic ecosystems have led to increased frequency, duration and toxicity of cyanobacterial blooms worldwide. This makes the provision of time series information on cyanotoxins extremely crucial for effective monitoring and management of water resources. The objective of the present study was to investigate seasonal and annual changes in microcystins (MCs), cylindrospermopsins (CYNs), saxitoxins (STXs), neo-saxitoxin (neo-STX) and anatoxin-a (ATX-a) concentrations in 11 public water supply reservoirs in the semiarid region of Brazil, from 2004 to 2011. Per time, at least one cyanotoxin was present in all the investigated reservoirs. High levels of MCs, CYNs, STXs and Neo-STX were detected simultaneously in Carpina, Duas Unas, Ipojuca, and Jucazinho reservoirs. All the investigated reservoirs had significant concentrations of MCs. The highest levels of MCs were found in Carpina (303,300.0 ng g?1) and Duas Unas (122,053.9 ng g?1) reservoirs, while the lowest concentration of the hepatotoxins was recorded in Ipojuca (10.3 ng g?1) reservoir. On the other hand, CYN was detected in four reservoirs, STXs and Neo-STX in ten reservoirs and ATX-a in two reservoirs. The first record of CYN in Carpina reservoir was obtained in 2006. In addition, Carpina reservoir had the highest concentration of STXs and Neo-STX in the dry and rainy seasons, respectively. The high concentration of cyanotoxins observed in most samples obtained from semiarid reservoirs in Brazil demonstrates the need for regular monitoring and updated management programs.  相似文献   

9.
The goal of this study was to evaluate the soil properties and their modifications within the rhizosphere of spontaneous vegetation as key factors to assess the phytomanagement of a salt marsh polluted by mining wastes. A field survey was performed based on a plot sampling design. The results provided by the analyses of rhizospheric soil (pH, electrical conductivity (EC), organic carbon, total nitrogen, etc.) and metal(loid)s’ phytoavailability (assessed by EDTA) were discussed and related to plant metal uptake. The averages of pH and EC values of the bulk soil and rhizospheric samples were in the range of neutral to slightly alkaline (pH 7–8) to saline (>2 dS m?1), respectively. Heavy metal and As concentrations (e.g. ~600 mg kg?1 As, ~50 mg kg?1 Cd, ~11,000 mg kg?1 Pb) were higher in the rhizosphere for both total and EDTA-extractable fraction. Phragmites australis uptaked the highest concentrations in roots (e.g. ~66 mg kg?1 As, ~1,770 mg kg?1 Zn) but not in shoots, for which most of plant species showed low values for Zn (<300 mg kg?1) but not for Cd (>0.5 mg kg?1) or Pb (~20–40 mg kg?1). Vegetation distribution in the studied salt marsh looked to be more affected by salinity than by metal pollution. The free availability of water for plants and the incoming nutrient-enriched effluents which flow through the salt marsh may have hindered the metal(loid)s’ phytotoxicity. The phytomanagement of these polluted areas employing the spontaneous vegetation is a good option in order to improve the ecological indicators and to prevent the transport of pollutants to nearby areas.  相似文献   

10.
Karst areas have much higher ecological vulnerability and are prone to be contaminated. Organochlorine pesticides (OCPs) were detected in waters and sediment from the two sites of the karst Nanshan underground river system, China, to understand the sources and transport of OCPs in the underground river systems. Obviously, seasonal variations were found both in the waters and the sediments. Detected OCPs ranged from 61 to 936 ng L?1 in the groundwaters and 51–3,842.0 ng g?1 in the underground sediments, respectively. OCPs in groundwaters were mixture of younger and older residues from commercial sources. The maximum OCPs in the sediments of the underground river were historically older residues from commercial sources. The sources of OCPs in the waters and sediments of the underground river indicated that the surface systems play an important role in OCPs transport and pollution in the underground river. Karst features were liable for the transport behavior.  相似文献   

11.
Levels and distributions of organochlorine pesticides (OCPs) and phenolic endocrine-disrupting chemicals (EDCs) in surficial sediments of the Shaying River, the largest tributary of the Huaihe River in eastern China, were investigated to understand their relationship with the hydrodynamics. Concentrations of total hexachlorocyclohexane isomers (ΣHCHs) and dichlorodiphenyltrichloroethanes (ΣDDT) were in the range of 26.7–119 and 9.64–214 ng g?1 with mean values of 104 and 80.7 ng g?1, respectively. Residues of HCHs in sediments can be considered as originating from the application of both technical mixtures and lindane in the past. According to the spatial distribution of (DDD + DDE)/ΣDDT ratios, the influence of recent DDT inputs was dominant upstream, whereas DDD prevailed downstream, due to anaerobic degradation. Concentrations of total phenolic EDCs (ΣEDCs) including nonylphenol (NP), octylphenol (OP) and bisphenol A (BPA) ranged widely from 425 to 3,953 ng g?1 with the highest level occurring in the middle reach. This accumulation could be attributed to the retransfer of surficial sediment from upstream, where the main sources are located. Spatial distribution of contaminants indicated that riverine hydrodynamics can significantly affect their behavior and fate in sediment. This evidence was further verified by multivariate statistical techniques such as Cluster Analysis (CA), Principle Component Analysis (PCA) and Discriminant Analysis (DA). The CA identified three distinct clusters reflecting the large complexity of river system like geography setting, hydrodynamic condition, etc. This finding was also confirmed by the DA. Furthermore, a PCA demonstrated that about 80.8 % of total spatial variance can be explained by the first three factors, which also indicated that contaminant spatial distributions are driven by local inputs, biodegradation and riverine hydrodynamics.  相似文献   

12.
Algal species which are ubiquitous along the coastlines of many countries reflect the environmental conditions of the coastal seawater and may serve as useful biomonitors of anthropogenic pollution. Heavy metal concentrations of ten elements (As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) of potential environmental concern were determined in seawater, sediments and twelve species of benthic marine macroalgae from four locations (Glenelg, Port Adelaide, Port Broughton and Port Pirie) along the South Australian coastline. The four sites chosen represented varying degrees of metal contamination, where the capacity for benthic macroalgae to accumulate heavy metals from the environment was evaluated. Spatial differences in heavy metal concentration in both seawaters and sediments were observed at all sites with the highest concentrations of heavy metals including Cd (125 μg g?1), Pb (2,425 μg g?1) and Zn (7,974 μg g?1) found in the finer sediment fractions (<250 μm) of Port Pirie. While all algal species studied (Acrosorium polyneurum, Anotrichium tenue, Cystophora Cephalornithos Cystophora monillifera, Cystophora monilliformis, Dictyopteris australis, Gelidium micropterum, Gracilaria, Hormophysa Cuneiformis, Sargassum cinctum, Scaberia agardhii and Ulva lactuca) accumulated metals to varying degrees, Blindigia marginata was a good biomonitor species for a number of metals including Cd, Co, Cr, Fe, Pb and Zn, exhibiting both relatively high total metal concentrations and significant concentration factors.  相似文献   

13.
Different bacterial and fungal strains, isolated from petroleum hydrocarbon-contaminated soil, were tested, in isolation as well as in combination, for their ability to degrade total petroleum hydrocarbon (TPH) in soil samples spiked with crude oil (2, 5 or 10 %, w/w) for 30 days. The selected combination of bacterial and fungal isolates, i.e., Pseudomonas stutzeri BP10 and Aspergillus niger PS9, exhibited the highest efficiency of TPH degradation (46.7 %) in soil spiked with 2 % crude oil under control condition. Further, when this combination was applied under natural condition in soil spiked with 2 % (w/w) crude oil along with inorganic fertilizers (NPK) and different bulking agents such as rice husk, sugarcane, vermicompost or coconut coir, the percent degradation of TPH was found to be maximum (82.3 %) due to the presence of inorganic fertilizers and rice husk as bulking agent. Further, results showed that the presence of NPK and bulking agents induced the activity of degradative enzymes, such as catalase (0.718 m mol H2O2 g?1), laccase (0.77 µmol g?1), dehydrogenase (37.5 µg g?1 h?1), catechol 1, 2 dioxygenase (276.11 µ mol g?1) and catechol 2, 3 dioxygenase (15.15 µ mol g?1) as compared to control (without bioaugmentation). It was inferred that the selected combination microbes along with biostimulants could accentuate the crude oil degradation as evident from the biostimulant-induced enhanced activity of degradative enzymes.  相似文献   

14.
For determination of atrazine isotherms in agricultural soils of Fars Province, composite soil samples from 0 to 5 cm depth with textures of silty clay loam, clay loam and loam were collected. In order to form the atrazine isotherms, 10, 50 and 100 µg atrazine g?1 soil was added to the soil samples. Soluble atrazine in water:soil ratios of 10:1, 50:1 and 200:1 was measured after 3-h shaking. Finally, for each cases of applied atrazine, water extractable atrazine was determined and quantified using gas chromatography instrument. The results indicated that there was a linear relationship between the logarithms of water extractable atrazine and added atrazine for different water:soil ratios. A general equation of WEA = K(WS) α (AA) β is obtained experimentally between water extractable atrazine, µg g?1(WEA), and added atrazine, µg g?1 (AA), where K, α and β are absorption constants; WS is the water:soil ratio, g g?1. For the loam, silty clay loam and clay loam soil textures, the α were 0.49, 0.23 and 0.13, respectively, the β were 0.55, 0.806 and 0.21, respectively, and the K were 1.44, 0.78 and 25.38, respectively.  相似文献   

15.
The objective of this work was to study sorption–desorption and/or precipitation–dissolution processes of Hg(II) compounds considering an eventual contact of soils with Hg-bearing wastes. In addition, this study contributes new data about Hg(II) chemistry in alkaline systems. Saline and alkaline soils with low organic matter (<1 %) and high clay content (60–70 %) were obtained near a chlor-alkali plant. Batch techniques were used to perform the experiments using 0.1 M NaNO3 solutions. Total Hg(II) concentrations ranged from 6.2 × 10?8 to 6.3 × 10?3 M. Sorption of Hg(II) was evaluated at two concentration ranges: (a) 6.2 × 10?8 to 1.1 × 10?4 M, and (b) 6.4 × 10?4 to 6.3 × 10?3 M. At low Hg(II) concentrations, adsorption occurred with a maximum sorption capacity ranging from 4 to 5 mmol/kg. At high Hg(II) concentrations, sorption–precipitation reactions occurred and maximum sorption capacity ranged from 17 to 31 mmol/kg. The distribution of Hg(II) hydrolysis products showed that Hg(OH)2 was the predominant species under soil conditions. According to sorption experiments, X-ray diffraction and chemical speciation modelling, the presence of Hg(OH)2 in the interlayer of the interstratified clay minerals can be proposed. Hg(OH)2 was partially desorbed by repeated equilibrations in 0.1 M NaNO3 solution. Desorption ranged from 0.1 to 0.9 mmol/kg for soils treated with 5.8 × 10?5 M Hg(II), whereas 2.1–3.8 mmol/kg was desorbed from soils treated with 6.3 × 10?3 M Hg(II). Formation of soluble Hg(II) complexes was limited by low organic matter content, whereas neutral Hg(OH)2 was retained by adsorption on clay mineral surfaces.  相似文献   

16.
Karst areas have much higher ecological vulnerability and are easy to be contaminated by polycyclic aromatic hydrocarbons (PAHs), which are introduced as health risk pollutants. PAHs ratios were used to understand the sources and transport behavior of PAHs conducted in the karst Nanshan Underground River, China. Water, sediments from the underground river and water, sediments, soil from the surface were collected monthly in 2011 and 2012. Abundant PAHs were found both in the underground river and in the surface system. The detected ΣPAHs concentrations varied from 353 to 13,203 ng L?1 in the groundwaters and content from 169 to 12,038 ng g?1 in the sediments of the underground river. The ratios of anthracene to anthracene, plus phenanthrene and fluoranthene to fluoranthene, plus pyrene indicated that PAHs were delivered in the groundwaters from combusted grass, wood, and coal, while in the sediments were a mixture of non-combusted petroleum, grass, wood, coal and combusted grass, wood, coal. The similarities in sources between an underground river and surface system indicated that farmlands play a major role for the transport of PAHs and contamination in the underground river. Karst features are liable for the transport behavior.  相似文献   

17.
This work was carried out in order to study the impact of car body repair activities in Bouzaréah City (suburban area located at the plateau of Algiers) on the air quality. Atmospheric particulate matter was targeted using high-volume sampler. Precisely, the particulate organic matter such as organophosphate esters, especially triphenyl phosphate and tributyl phosphate, was evaluated by the implementation of accelerated solvent extraction. The results of the major extractable organic components revealed that tributyl phosphate and triphenyl phosphate were found at 5.46 and 1.78 ng m?3, respectively. On the other hand, the classical pollutants such as n-alkanes, n-alkanoic monocarboxylic acids and polycyclic aromatic hydrocarbons were also measured, respectively, at average total concentrations of 35.8, 107.4 and 9.8 ng m?3. This work confirms that sanding and painting car bodies may contribute to air pollution, especially after detection of diethylnitrosamine which remains the most surprising compound in the particulate matter due to its volatility and can be considered as emerging contaminant.  相似文献   

18.
The contents of Co, Cr, Cu, Mn, Ni, Pb and Zn in the dust samples collected from Changqing industrial park of Baoji city, NW China, were measured by XRF, while As and Hg in the dust samples were analyzed by AFS. Geo-accumulation index (I geo), pollution index (PI) and integrated pollution index (IPI) were calculated to evaluate the heavy metal contamination level of dust. The health risk due to exposure to heavy metals in dust was analyzed by the Health Risk Assessment Model of US EPA. The results show that the arithmetic means of As, Co, Cr, Cu, Hg, Mn, Ni, Pb and Zn are 23.3, 16.4, 1591.8, 178.2, 0.243, 346.5, 40.2, 1,586.2 and 1,918.8 mg kg?1, respectively, which are higher than the background values of Shaanxi soil, especially for Cr, Cu, Hg, Pb, and Zn. The mean values of I geo reveal the order of Pb > Zn > Cr > Hg > Cu > As > Co > Ni > Mn. The high I geo of Cr, Cu, Hg, Pb and Zn in dust indicates that there is considerable pollution from Cr, Cu, Hg, Pb and Zn, while the low I geo of As, Co, Mn and Ni presents no pollution in dust. The assessment results of PI support the results of I geo, and IPI indicates heavy metals in dust polluted seriously. The health risk assessment shows that ingestion of dust particles is the route for exposure to heavy metals from dust, followed by dermal adsorption. Exposure to As, Cr and Pb from dust may pose a potential health threat to children and adults. The risk of cancer from As, Co, Cr and Ni due to dust exposure is low.  相似文献   

19.
Abstract Karst areas have much higher ecological vulnerability and are easy to be contaminated by polychlorinated biphenyls(PCBs) which are introduced as health risk pollutants.PCBs concentrations were used to understand the transport behavior of PCBs conducted in the karst Nanshan Underground River,China.Water and sediments from the underground river water,and sediments and soil from the surface of the corresponding watershed were collected monthly in 2011 and 2012 and PCBs were analyzed.Seasonal variations were found in concentrations of PCBs both in the waters and sediments.PCBs concentrations varied from 0.3 to 29.9 ng·L-1 in the groundwater,while from 0.1 to 366.1 ng·g-1 in the underground sediments.Correlations were found in concentrations of PCBs in waters and sediments between the underground river and surface systems which indicate that the surface systems play a major role for the transport of PCBs and contamination in the underground river systems.Karst features are liable for the transport behavior.The underground river waters transport PCBs at mean 3 g·day-1.  相似文献   

20.
Wastewater biosolids are large potential sources of macronutrients for agriculture, conservation and restoration of soils; there are, however, few studies on phosphorus (P) release in soils amended with biosolids. Biosolids and vermicomposted biosolids were tested in concentrations (5–30 g amendment kg?1 soil) equivalent to 18–100 Mg ha?1. Desorption of P was determined by successive extractions for 65 days. Soil P was low, and biosolid and vermicompost addition released 8 and 6 times more P, respectively, than soil alone. To describe the release of P, zero-, first- and second-order equations, simple Elovich and power functions and the parabolic diffusion law were compared based on their coefficient of determination (r 2) and standard error (SE). In all treatments, the power function and especially the parabolic diffusion law were the best fit, with 0.898–0.996 r 2 and 0.022–0.732 SE. The general behavior of the kinetic parameters mostly depended on the amendment doses. Eutrophication posited to start beyond 16 mg P kg?1 soil was more likely allayed by a maximum vermicompost dose of 50 Mg ha?1, higher than the 36 Mg ha?1 maximum biosolid dose. The higher vermicompost P addition and lower P release could favor gradual and longer-term P absorption by plants and may reduce leaching or runoff P losses.  相似文献   

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