杀虫剂十氯酮的多介质环境行为模拟

应用EQC模型模拟十氯酮在多介质环境中的归宿和迁移通量.结果表明:土壤是十氯酮最大的贮存库,在稳态平衡条件下,残留率达到95.0%;在稳态非平衡条件下,十氯酮单独排放到水体,有37.5%残留在于排放的水体中,其在大气的浓度水平和质量分布均很低,在沉积物中的质量则来自于水体向沉积物的沉降迁移;十氯酮主要通过水体的水平迁移和土壤的厌氧降解输出;十氯酮的主要界面迁移过程是大气向土壤的迁移,其次是水体向沉积物的沉降和大气向水体的迁移.     

Unidirectional gas flow in soil porosity resulting from barometric pressure cycles

During numerical simulation of air flow in the vadose zone, it was noticed that a small sinusoidal pressure would cause a gradual one-way migration of the pore gas. This was found to be a physical phenomenon, not a numerical artifact of the finite element simulation. The one-way migration occurs because the atmospheric pressure, and hence the air density, is slightly greater when air is flowing into the ground than when air is flowing out of the ground. A simple analytic theory of the phenomenon is presented, together with analytic calculations using actual barometric pressure data. In soil of one Darcy permeability, the one-way migration is of the order of a few tenths of a meter per year for either plane flow from ground surface or for radial flow from an open borehole. The migration is sufficiently small that it will have no practical consequences in most circumstances; however, investigators who conduct detailed numerical modeling should recognize that this phenomenon is not a numerical artifact in an apparently linear system.     

Determination of soil content in chlordecone (organochlorine pesticide) using near infrared reflectance spectroscopy (NIRS)

Chlordecone is a toxic organochlorine insecticide that was used in banana plantations until 1993 in the French West Indies. This study aimed at assessing the potential of near infrared reflectance spectroscopy (NIRS) for determining chlordecone content in Andosols, Nitisols and Ferralsols from Martinique. Using partial least square regression, chlordecone content conventionally determined through gas chromatography–mass spectrometry could be correctly predicted by NIRS (Q² = 0.75, R² = 0.82 for the total set), especially for samples with chlordecone content <12 mg kg⁻¹ or when the sample set was rather homogeneous (Q² = 0.91, R² = 0.82 for the Andosols). Conventional measures and NIRS predictions were poorly correlated for chlordecone content >12 mg kg⁻¹, nevertheless ca. 80% samples were correctly predicted when the set was divided into three or four classes of chlordecone content. Thus NIRS could be considered a time- and cost-effective method for characterising soil contamination by chlordecone.     

Evaluation of the ecotoxicological impact of the organochlorine chlordecone on soil microbial community structure,abundance, and function

The insecticide chlordecone applied for decades in banana plantations currently contaminates 20,000 ha of arable land in the French West Indies. Although the impact of various pesticides on soil microorganisms has been studied, chlordecone toxicity to the soil microbial community has never been assessed. We investigated in two different soils (sandy loam and silty loam) exposed to different concentrations of CLD (D0, control; D1 and D10, 1 and 10 times the agronomical dose) over different periods of time (3, 7, and 32 days): (i) the fate of chlordecone by measuring ¹⁴C-chlordecone mass balance and (ii) the impact of chlordecone on microbial community structure, abundance, and function, using standardized methods (-A-RISA, taxon-specific quantitative PCR (qPCR), and ¹⁴C-compounds mineralizing activity). Mineralization of ¹⁴C-chlordecone was inferior below 1 % of initial ¹⁴C-activity. Less than 2 % of ¹⁴C-activity was retrieved from the water-soluble fraction, while most of it remained in the organic-solvent-extractable fraction (75 % of initial ¹⁴C-activity). Only 23 % of the remaining ¹⁴C-activity was measured in nonextractable fraction. The fate of chlordecone significantly differed between the two soils. The soluble and nonextractable fractions were significantly higher in sandy loam soil than in silty loam soil. All the measured microbiological parameters allowed discriminating statistically the two soils and showed a variation over time. The genetic structure of the bacterial community remained insensitive to chlordecone exposure in silty loam soil. In response to chlordecone exposure, the abundance of Gram-negative bacterial groups (β-, γ-Proteobacteria, Planctomycetes, and Bacteroidetes) was significantly modified only in sandy loam soil. The mineralization of ¹⁴C-sodium acetate and ¹⁴C-2,4-d was insensitive to chlordecone exposure in silty loam soil. However, mineralization of ¹⁴C-sodium acetate was significantly reduced in soil microcosms of sandy loam soil exposed to chlordecone as compared to the control (D0). These data show that chlordecone exposure induced changes in microbial community taxonomic composition and function in one of the two soils, suggesting microbial toxicity of this organochlorine.     

Arsenic and chlordecone contamination and decontamination toxicokinetics in Sargassum sp.

Environmental Science and Pollution Research - Massive Sargassum sp. beachings have been occurring on Caribbean shores since 2011. The sargassum involved in such events are S. fluitans and S....     

Changes in soil microbial biomass and Zn extractability over time following zn addition to a paddy soil

A laboratory incubation study was conducted using a paddy soil spiked with two quantities of Zn as soluble Zn(NO3)2 and unamended controls. Three single extractants (1 M ammonium acetate (pH 7.0), 0.43 M acetic acid and 0.05 M EDTA) were used to assess the bioavailability of Zn. Biological community assessments were made microbial biomass (chloroform fumigation), soil basal respiration and dehydrogenase activity. During the 84-day period of the experiment, addition of Zn at both 500 and 1,000 mg kg(-1) had little detectable effect on soil pH. The concentration of NH4OAc-extractable Zn decreased rapidly within the initial six weeks. The concentration of HOAc-extractable Zn showed no decrease during 84 days incubation. EDTA-extractable Zn was greater than NH4OAc- and HOAc-extractable fractions, and showed a similar trend to NH4OAc-extractable after incubation. Microbial biomass, soil basal respiration and dehydrogenase activity all decreased over time during 84 days incubation. Addition of Zn resulted in a significant increase in specific respiration (qCO2). Microbial biomass and dehydrogenase activity did not appear to be influenced by added Zn, probably due to the strong buffering capacity of the soil. The Zn extracted by EDTA, HOAc and NH4OAc showed close relationships with each other (p < 0.001). Zinc extracted by 0.05 M EDTA and NH4OAc were highly correlated with soil basal respiration and specific respiration rate (p < 0.01). The results suggest that NH4OAc-extractable Zn combined with soil specific respiration could be used as parameters for risk assessment.     

污泥施用对根际和非根际石灰性土壤中细菌多样性的影响

为研究污泥施用对石灰性土壤细菌多样性的影响,在连续2年种植夏玉米大田系统中,施用不同量的腐熟污泥,采集根际和非根际土壤进行16S rDNA-V3-V4区高通量测序,分析污泥施用对石灰性土壤细菌丰富度、多样性指数、群落结构、功能基因在代谢途径的影响,同时对细菌群落和环境因素之间的相关性进行分析。结果表明：污泥用量分别在3.5～37.5 t·hm⁻²和3.5～7.5 t·hm⁻²有利于非根际和根际土壤OTU数量增加;但污泥在75 t·hm⁻²过量施用时,根际和非根际土壤细菌的Shannon多样性指数显著降低,Simpson指数显著增加,Ace,Chao丰富度指数显著降低。主成分和门水平物种丰度分析表明：污泥施用量不同会造成根际和非根际细菌群落结构差异,并且当污泥施用量为75 t·hm⁻²时,明显降低了非根际土壤放线菌门的丰度;污泥施用量在3.75～37.5 t·hm⁻²时,非根际土壤中拟杆菌门丰度会明显增加。与对照相比,当污泥用量为75 t·hm⁻²时,根际土壤拟杆菌门有明显的增加,增加丰度达1.45倍,但酸杆菌门和放线菌门丰度降低了49.74%和80.57%。冗余分析(RDA)表明,土壤TN、Cd、Cu、TP是影响土壤细菌群落最主要的因素,其中TN、Cd、Cu和细菌Shannon、Simpson多样性指数呈现显著相关性(P< 0.05)。由此可见,连续过量施入污泥会对根际和非根际石灰性土壤中细菌多样性造成不利影响,而且上述微生物多样性变化可作为污泥合理施用的判断依据。     

Fate of pharmaceutical compounds and steroid hormones in soil: study of transfer and degradation in soil columns

Numerous chemical products are dispersed into the environment, and the consequences can be sometimes harmful to humans and ecosystems. Pharmaceutical compounds and hormone steroids are among these substances that concern the scientific community. Currently, little data are available on the presence and fate of these compounds in the environment and, in particular, for solid matrices. Therefore, the aim of this work was to perform soil column experiments to evaluate the accumulation, transfer and degradation of these substances in soil. The analyses were based on efficient sample preparation followed by sensitive and selective liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). For this purpose, 23 compounds were chosen including both pharmaceutical compounds as well as steroid hormones. In addition, this experiment was performed on two soils with different properties (% clay, pH, etc.). To the best of our knowledge, no soil column experiments have been performed previously on a large number of pharmaceutical compounds and steroid hormones. Significant transfer was observed only for sulphonamides that can be justified by their polarity (log K _ow ?相似文献   

添加堆肥和赤泥对土壤生物有效性Cd和Zn的影响

采用土壤培养实验,研究添加堆肥和赤泥对土壤中Zn和Cd生物有效性的影响。结果表明,单独添加堆肥或赤泥以及赤泥和堆肥一起添加到土壤,均可以降低土壤中的交换态Cd和Zn含量以及生物有效态Zn和Cd含量。与对照相比,培养1~3个月后,单独添加堆肥、单独添加赤泥和同时添加赤泥与堆肥导致土壤交换态Cd含量分别降低14%~18%、33.3%~46.1%和44.2%~57.7%;土壤交换态Zn含量分别降低54.4%~59%、100%和100%;土壤生物有效态Cd含量分别降低11.8%~14.7%、25.1%~33.7%和32.6%~43.9%;土壤生物有效态Zn含量分别降低14.1%~15.8%、59.7%~72.2%和43.2%~58.4%。     

鸟粪石负载硅藻土对土壤铅和金霉素的同步修复作用

使用镁盐改性硅藻土回收沼液中氮磷制得鸟粪石负载硅藻土 (Struvite-loaded diatomite,SD) ,将其用于土壤中铅 (Pb) 和金霉素 (CTC) 复合污染的原位修复。采用吸附-解吸实验评估SD对Pb和CTC迁移特性的影响,同时,通过测定土壤pH和酸缓冲能力、土壤Pb和CTC的有效态和形态、土壤速效磷和微生物群落结构变化等考察SD对土壤Pb和CTC的钝化能力,借助SEM、XRD、FT-IR等表征手段揭示其修复机理。结果表明,SD能有效降低Pb和CTC在土壤中的迁移特性;SD投加质量分数为3%,稳定49 d后,土壤酸中和能力提升1倍以上,土壤有效态Pb和CTC含量分别降低26%和56%,酸溶态Pb占比降低10%,残渣态Pb占比升高18%, CTC的水溶态和松散结合态占比分别降低5%和13%,紧密结合态CTC升高11%,一定程度上降低了Pb和CTC在土壤中的生物有效性;SD的投加可提升土壤速效磷含量,提高土壤微生物的相对丰度和多样性,尤其增加酸杆菌门 (Acidobacteria) 、绿弯菌门 (Chloroflexi) 和芽单胞菌门 (Gemmatimonadetes) 的相对丰度,降低放线菌门 (Actinobacteria) 和厚壁菌门 (Firmicutes) 的相对丰度;SD对土壤Pb和CTC的钝化机制主要为吸附和沉淀的协同作用。该研究可为污水氮磷资源化利用和重金属抗生素复合污染土壤原位修复提供参考。     

投加硝酸钙对城市黑臭河道底泥氮迁移转化的影响

投加硝酸钙是目前河道黑臭底泥原位治理常用的方法,然而,投加硝酸钙会造成底泥硝态氮和氨氮的过量释放,而其影响机制尚未明确。因此有必要对投加硝酸钙后硝态氮在底泥中的迁移转化规律及其促进氨氮释放的机理进行研究。结果发现,硝酸盐在间隙水的迁移距离取决于硝态氮反硝化速率,而在黑臭底泥中硫化物氧化是影响反硝化速率的关键因素。当硝酸钙投加量为20 g/kg时,硝态氮的迁移距离小于6 cm,且在14 d后消耗光;可见,通过控制硝酸钙在底泥中的投加位置可避免硝态氮的二次释放。另一方面,投加硝酸钙会促进底泥氨态氮向间隙水释放,投加当天释放率可高达101%,且会在间隙水中发生累积迁移。其中,氨氮的增加量和底泥氨态氮解吸量呈一级线性关系(r=0.986)、和硝酸钙投加量关系符合cubic曲线;据此可推测,氨氮的急剧释放与钙离子对底泥铵态氮的化学浸提有关。     

磷回收产物对土壤中铜的原位修复作用

以鸟粪石形式回收废水中磷酸盐并将其应用于土壤中铜的钝化,通过测定土壤中pH、铜有效态含量和各形态铜含量等以考察磷回收产物（PRP材料）对土壤重金属铜的钝化修复能力,并用SEM/EDS和XRD等表征手段来揭示其修复机理。实验结果表明,PRP材料的主要成分为负载有鸟粪石的人造沸石;在15% PRP材料的投加比例下,土壤的pH增加了0.47个单位,土壤中铜有效态含量减少了50.4%,可交换态含量降低了49.4%,残渣态增加至2.1倍,一定程度上降低了铜在土壤中的生物活性;PRP材料对土壤中重金属Cu的钝化机制主要为吸附和沉淀的协同作用。     

赤泥对污染土壤Pb、Zn化学形态和生物可给性的影响

通过土壤培养实验,研究添加赤泥对污染土壤中Pb、Zn化学形态和生物可给性的影响。结果表明,不同赤泥用量处理均可显著降低土壤中HOAc提取态Pb、Zn含量。当赤泥用量为5%时,培养1、2和3个月后,HOAc提取态Pb含量分别比对照下降62.5%、65.3%和73.5%;HOAc提取态Zn含量分别比对照下降56.7%、65.8%和67.4%。培养3个月后,只有1%赤泥用量处理显著降低了土壤中生物可给性Pb含量,而不同用量赤泥处理均显著降低了土壤中生物可给性Zn含量。研究表明赤泥是一种钝化污染土壤中Pb、Zn的潜力添加剂。     

生物质炭添加量对BDE-47在土壤中吸附和解吸行为的影响

研究了添加生物质炭对2,2’,4,4’-四溴联苯醚(BDE-47)在土壤中吸附和解吸行为的影响。结果表明,在受试天然土壤中添加不同量的生物质炭,土壤对BDE-47吸附能力的变化程度也将不同,当生物质炭添加量为2.0%(质量分数,下同)以下时,随着生物质炭添加量的增加,土壤对BDE-47吸附能力的提高程度越明显,BDE-47的解吸滞后性则呈现先上升后下降的趋势。当生物质炭添加量为0.1%、0.5%时,土壤单点分配系数分别为原土壤的0.98~1.39、1.02~1.50倍;当生物质炭添加量为1.0%、2.0%时,土壤单点分配系数分别为原土壤的1.44~1.68、3.25~3.27倍;生物质炭添加量为1.0%时,BDE-47的解吸滞后性最显著。     

Compost amendment of Cu-Zn minespoil reduces toxic bioavailable heavy metal concentrations and promotes establishment and biomass production of Bromus carinatus (Hook and Arn.)

A series of lab and greenhouse studies were undertaken to understand how Cu and Zn toxicity influences Bromus carinatus (Hook and Arn.) growth, to what degree an organic amendment (yard waste compost) may reduce Cu and Zn bioavailability in Cu-Zn minespoil and promote plant growth in combination with fertilizer, and how the vertical distribution of compost in the minespoil influences rooting depth. Root Cu and Zn toxicity thresholds were determined to be 1 mgL(-1) and 10 mgL(-1) in solution, respectively. The compost amendment had exceptionally high Cu and Zn binding capacities (0.17 and 0.08 g metal g C(-1), for Cu and Zn, respectively) that were attributed to high compost humic and fulvic acid concentrations. Maximum plant biomass was achieved when minespoil was amended with compost and fertilizer in combination. Fertilizer alone had no effect on plant growth. Mixing compost into the minespoil was essential to promote adequate rooting depth.     

The addition of modified attapulgite reduces the emission of nitrous oxide and ammonia from aerobically composted chicken manure

The acceleration of the composting process and the improvement of compost quality have been explored by evaluating the efficacy of various additives, inoculating with specific microorganisms and the application of various biosurfactants. The magnesium-aluminum silicate attapulgite is a low-cost potential composting additive, but its effects on aerobic composting are unknown. This study investigated the effects of attapulgite application on compost production and quality during the aerobic composting of chicken manure. Addition of attapulgite significantly increased the temperature (p < 0.05) while it reduced compost total organic carbon (TOC) and seed germination indices (GIs) throughout the process. Its addition enhanced nitrate concentrations, promoted organic matter degradation, increased seed germination indices, and accelerated the composting process. Interestingly, attapulgite addition did not increase the population of ammonia-oxidizing bacteria. These results suggest that attapulgite is a good additive for the composting industry.

Implications: We investigated the addition of two forms of attapulgite during aerobic composting of chicken manure to determine their effects under strict composting environmental parameter control. Our results provides primary evidence that attapulgite may have potential for application in the composting industry.

All treatments showed no increase within the first 15 days. However, emissions increased for all treatments within 15–45 days, reaching approximately 6300, 2000, and 4000 mg/m² from the control, artifactitious attapulgite, and raw attapulgite treatments, respectively.     

Combined effects of nitrogen addition and organic matter manipulation on soil respiration in a Chinese pine forest

The response of soil respiration (Rs) to nitrogen (N) addition is one of the uncertainties in modelling ecosystem carbon (C). We reported on a long-term nitrogen (N) addition experiment using urea (CO(NH₂)₂) fertilizer in which Rs was continuously measured after N addition during the growing season in a Chinese pine forest. Four levels of N addition, i.e. no added N (N0: 0 g N m⁻² year⁻¹), low-N (N1: 5 g N m⁻² year⁻¹), medium-N (N2: 10 g N m⁻² year⁻¹), and high-N (N3: 15 g N m⁻² year⁻¹), and three organic matter treatments, i.e. both aboveground litter and belowground root removal (LRE), only aboveground litter removal (LE), and intact soil (CK), were examined. The Rs was measured continuously for 3 days following each N addition application and was measured approximately 3–5 times during the rest of each month from July to October 2012. N addition inhibited microbial heterotrophic respiration by suppressing soil microbial biomass, but stimulated root respiration and CO₂ release from litter decomposition by increasing either root biomass or microbial biomass. When litter and/or root were removed, the “priming” effect of N addition on the Rs disappeared more quickly than intact soil. This is likely to provide a point of view for why Rs varies so much in response to exogenous N and also has implications for future determination of sampling interval of Rs measurement.

     

Effect of sludge-amendment or nutrient addition on the biodegradation of the herbicide isoproturon in soil

Adding sludge to agricultural soil results in added organic matter, nutrients and metallic and/or organic pollutants. These components may modify the behaviour of pesticides in the soil. We monitored possible changes in the degradation of the herbicide isoproturon (production of CO2 and degradation products) in soil amended with sludge, heavy metals or nitrogen and phosphorus. The treated and control soils were incubated under controlled conditions for 60 days. The nitrogen and phosphorus had the greatest effect on isoproturon degradation, independent of the presence of pollutants. Mineralisation of the herbicide to CO2 was slow and seemed to be linked to a fast degradation and to the accumulation of a complex degradation product that was neither catabolized nor adsorbed, 4,4'-diisopropylazobenzene. This degradation pathway also produced smaller amounts of non-extractable residues. Sewage sludge had no significant effect on isoproturon degradation, despite a large increase of organic matter mineralisation (factor 2).     

Soil Cd availability to Indian mustard and environmental risk following EDTA addition to Cd-contaminated soil

A pot experiment was conducted to investigate the influence of EDTA on the extractability of Cd in the soil and uptake of Cd by Indian mustard (Brassica juncea). Twenty levels of soil Cd concentration ranging from 10 to 200 mg kg(-1) were produced by spiking aliquots of a clay loam paddy soil with Cd(NO3)2. One week before the plants were harvested EDTA was applied to pots in which the soil had been spiked with 20, 40, 60...200 mg Cd kg(-1). The EDTA was added at the rate calculated to complex with all of the Cd added at the 200 mg kg(-1) level. Control pots spiked with 10, 30, 50... 190 mg Cd kg(-1) received no EDTA. The plants were harvested after 42 days' growth. Soil water- and NH4NO3-extractable Cd fractions increased rapidly following EDTA application. Root Cd concentrations decreased after EDTA application, but shoot concentrations increased when the soil Cd levels were >130 mg kg(-1) and Cd toxicity symptoms were observed. The increases in soil solution Cd induced by EDTA did not increase plant total Cd uptake but appeared to stimulate the translocation of the metal from roots to shoots when the plants appeared to be under Cd toxicity stress. The results are discussed in relation to the possible mechanisms by which EDTA may change the solubility and bioavailability of Cd in the soil and the potential for plant uptake and environmental risk due to leaching losses to groundwater.     

Functional and community-level soil microbial responses to zinc addition may depend on test system biocomplexity

The effect of zinc on soil nitrification and composition of the microbial community in soil was investigated using a full factorial experiment with five zinc concentrations and four levels of biological complexity (microbes only, microbes and earthworms (Eisenia fetida), microbes and Italian ryegrass (Lolium multiflorum var. Macho), and microbes, ryegrass and earthworms). After 6 weeks of exposure, the activity of soil nitrifying bacteria was measured and the microbial community structure was characterized by phospholipid fatty acid (PLFA) analysis. Soil nitrification and several PLFA markers were significantly influenced by either zinc addition and/or the presence of earthworms or ryegrass, and one of the most pronounced changes was the increase of fungi and decrease of bacteria with increasing concentrations of zinc. Of particular interest, however, was the potential interaction between the presence of plants and/or earthworms and the effect of zinc, which the factorial study design allowed us to explore. Such an effect was observed in two cases: Earthworms reduced the positive effect of zinc on the fungal biomass (ANOVA, p=0.03), and the effect of earthworms on the soil nitrification activity depended on zinc concentration (ANOVA, p<0.05). The effect of earthworm presence was not very large, but it does show that multispecies tests might give information about metal toxicity or bioavailability that cannot be predicted from single-species tests.