基于耳石元素微化学的江苏吕泗近岸小黄鱼生境履历重建

利用电子显微探针元素分析技术,对江苏吕泗近岸海域小黄鱼矢耳石的Sr和Ca微化学特征进行了研究.结果表明: Sr含量在小黄鱼耳石的矢状面上呈非均匀分布,总体为核心部位高,其余部分明显降低.核心高Sr区域的Sr/Ca比值为(7.10±1.00),其余部分为(4.79±1.01),两者差异极显著.后者部分个体存在Sr含量更低的区域,Sr/Ca比值为(3.51±0.76).基于这些结果重建了吕泗近岸小黄鱼的生境履历： 它们在孵化及初期发育阶段生活在高盐度生境,随后的生长和发育过程则会洄游至盐度稍低的生境;部分个体的早期发育阶段还会选择利用更低盐度的生境.     

砷对土壤-蜈蚣草系统中磷生物有效性的影响

磷是植物必需的大量营养元素,而其同族元素砷却不是植物生长发育所必需的。通过等温吸附平衡实验发现土壤中存在的砷可以降低褐土对磷的吸附,褐土对砷的吸附率大于等于褐土对磷的吸附率。对砷超富集植物蜈蚣草而言,土壤中砷的添加量不超过800mg／kg时,蜈蚣草地上部和地下部磷含量显著提高,结果初步表明,砷可以提高土壤中磷的生物有效性。     

紫色土中砷、磷的吸附-解吸和竞争吸附

采用批培养法研究了As、P在三峡库区典型土壤紫色土中的吸附-解吸特点及竞争吸附对As、P迁移活化的影响.结果表明：3种紫色土中As、P的吸附-解吸特点相似,等温吸附均符合Langmuir和Freundlich方程,As在酸性、中性和石灰性紫色土中的最大吸附量分别为1428.6、1250.0和1111.1 mg·kg^-1;P在酸性、中性和石灰性紫色土中的最大吸附量分别为322.6、357.1和434.8 mg·kg^-1;As、P吸附动力学过程为先快后慢,均符合一级动力学方程与Elovich方程,快速吸附段符合一级动力学方程,为交换吸附;慢速吸附阶段满足Elovich方程,可能属于深层吸附或专性吸附.As、P竞争吸附试验表明,As、P共存时P的吸附速度和吸附量均增强,而As的吸附速度和吸附量均降低,表明As的存在能明显增强紫色土对P的吸附作用,P的存在则明显抑制紫色土对As的吸附.     

不同来源生物炭对砷在土壤中吸附与解吸的影响

采用OECD Guideline 106批平衡方法研究了由凋落松针、玉米秸秆、牛粪制备的3种生物炭对As(Ⅴ)在棕壤中的吸附和解吸特性的影响.结果表明：3种生物炭的添加量为0.5%时,对As(Ⅴ)在土壤中的吸附量大小顺序为牛粪炭处理＞松针炭处理＞玉米秸秆炭处理,这与生物炭的基本性质密切相关;等温吸附曲线能用Langmuir方程进行很好的拟合(R² =0.997);与对照相比,生物炭处理对砷的吸附容量(lgK_f 为1.99～2.10)和吸附强度(1/N 为0413～0.449)降低,生物炭对As(Ⅴ)的主要吸附机制为物理吸附;生物炭处理对As(Ⅴ)解吸率大小顺序为：玉米秸秆炭处理＞松针炭处理＞牛粪炭处理,解吸率在14.5%～18.7%.添加3种来源生物炭降低了棕壤对As(Ⅴ)的吸附,这可能会导致砷的有效性增强,更易被生物吸收,进而增强土壤中砷的毒性.     

外源二甲基砷对油菜生长及土壤中砷生物有效性的影响

通过盆栽试验研究了土壤中添加外源二甲基砷(DMA)对油菜(Brassica campestris)生长及土壤中砷生物有效性的影响.结果表明:随着外源DMA添加量的增加,油菜的出苗率和生物量均在一定程度上表现出了低浓度促进而高浓度抑制的现象.当外源DMA添加量达到90 mg·kg-1时,第2季盆栽油菜的出苗率和生物量与对照相比分别下降了9.5%和57.0%,表明DMA对油菜生长的影响具有长期性;随着外源DMA浓度的增加,土壤中有效态砷及油菜体内的砷含量均表现出增加的趋势,相关性分析表明,该三者间具有极显著相关关系;添加入土壤中的DMA主要发生去甲基化作用,产物主要为As(V)及少量的As(Ⅲ),且随着外源DMA添加量的增加,As(V)和As(Ⅲ)的浓度均表现出增加的趋势.     

氧化还原条件对湿地土壤磷吸附与解吸特性的影响

采用室内模拟试验研究了氧化还原条件对盘锦天然湿地土壤磷吸附与解吸特性的影响,并对磷的吸附与解吸过程进行拟合。结果表明,氧化或还原条件下Langmuir模型和Freundlich模型均能较好地拟合磷的等温吸附曲线,且Langmuir方程的拟合效果好于Freundlich方程。淹水还原条件下,湿地土壤对磷的最大吸附量和解吸率比淹水前分别降低了9.5%和16.3%;吸附解吸平衡浓度升高,平均增加158.8%。淹水后土壤活性铁含量明显升高,淹水前后活性铁变化与吸附解吸平衡浓度变化之间的相关性达到了显著水平,与土壤中磷的最大吸附量和解吸率变化的相关性不显著,表明活性铁含量的变化是淹水还原条件下影响土壤磷吸附解吸平衡浓度变化的主要因素。     

不同粒径生物炭对土壤磷吸附-解吸特性的影响

粒径是影响物质吸附性能的一个重要因素。本研究以不同粒径(0.25～1 mm、0.075～0.25 mm、<0.075 mm)油菜秸秆生物炭(SBC)和鸡粪生物炭(MBC)分别与两种土壤(高磷土、低磷土)混合进行室内培养30 d,通过土壤磷等温吸附试验与解吸试验,结合土壤磷吸附相关性质,评价不同粒径生物炭对土壤磷吸附-解吸特性的影响。结果表明：在水体系中,3个粒径的SBC与MBC对磷的吸附能力大小均表现为<0.075 mm(43125、20083 mg·kg^-1)>0.075～0.25 mm(37376、13199 mg·kg^-1)>0.25～1 mm(27749、12251 mg·kg^-1);在土壤体系中,同一种生物炭的3个粒径间土壤磷吸附量差异较小。与无生物炭处理相比,添加SBC提高了土壤对磷的最大吸附量(S_max),增幅为236.8%～755.7%,并降低了土壤磷解吸率;添加MBC的S_max增幅较SBC低,但提高了土壤磷解吸率(增幅为7.2%～295...     

外源腐殖酸对三种土壤磷吸附与解吸特性的影响

通过对3种土壤（红壤、棕壤和褐土）施入不同腐殖酸的室内培养试验,探讨了外源腐殖酸对不同土壤磷素吸附和解吸的影响。结果表明：与对照土壤相比,不同腐殖酸降低了3种供试土壤磷素的吸附量,其降低顺序为：褐土＞红壤＞棕壤;外源腐殖酸提高了红壤和棕壤磷素的解吸量和解吸率,提高的幅度与腐殖酸的种类有关;而腐殖酸对褐土磷素的解吸量则无明显促进作用。表明外源腐殖酸对3种土壤磷素吸附-解吸作用最强的为红壤,其次为棕壤,最弱的为褐土;同时表明腐殖酸可提高红壤和棕壤磷素的利用率。     

择伐干扰对小兴安岭阔叶红松林土壤磷吸附解吸的影响

以小兴安岭地区阔叶红松林经过轻度、中度和强度择伐干扰后形成的天然林以及未经干扰的原始林(对照)林地表层(0～10 cm)土壤为对象,对土壤磷素的最大吸附量、吸附强度、最大缓冲容量、最大解吸量、平均解吸率和易解吸磷量等指标进行测定,研究不同干扰强度导致土壤磷吸附解吸的规律性变化,分析择伐干扰对阔叶红松林土壤磷吸附解吸特征的影响.结果表明: 各林地土壤磷最大吸附量为1383.93～1833.34 mg·kg^-1,中度和强度干扰林地显著高于轻度干扰林地和原始林地;磷吸附强度为0.024～0.059 L·mg^-1,强度和轻度干扰显著增加了林地土壤磷吸附强度;最大缓冲容量为35.68～97.97 L·kg^-1,强度干扰林地土壤的最大缓冲容量最高.择伐干扰显著降低了林地土壤的供磷潜力.各样地土壤磷最大解吸量、平均解吸率和易解吸磷量分别为526.32～797.54 mg·kg^-1、14.7%～25.5%和1.79～5.41 mg·kg^-1,林地土壤磷素释放能力随干扰强度的增加显著降低.择伐干扰通过降低林地土壤磷的供应及释放能力改变了阔叶红松林土壤磷吸附与解吸特征.     

泉州市不同利用方式下土壤磷的吸附与解吸特性

分析了不同利用方式下泉州市土壤磷素吸附-解吸特征.结果表明:Langmuir等温方程式可以很好地表征土壤磷素的吸附特性;旱地和轮作地土壤对磷的吸附能力较强,而草地和林地土壤对磷的吸附能力较弱;磷的流失风险顺序为轮作地＞草地＞林地＞旱地;指导施磷量与吸附常数、最大缓冲量的大小顺序一致,为旱地＞轮作地＞林地＞草地;轮作地和草地的解吸率高于旱地和林地,土壤的缓冲能力顺序为旱地＞林地＞轮作地＞草地.主成分分析表明,平均解吸率、易解吸磷、磷吸附指数和磷零吸持平衡浓度4个指标最能反映土壤磷素流失潜力,可作为评价流失潜力的主要指标.     

蚯蚓活动对红壤磷素主要形态及有效磷含量的影响

通过盆钵生物试验和采用Hedley磷素分级方法研究了秉氏环毛蚓(Pheretima pingi)对红壤磷素主要形态和红壤有效磷含量的影晌.结果表明,在蚯蚓和有机物料(稻草、花生秸、油菜秸)的共同作用下,经过100d培养后土壤有效磷含量显著提高.统计分析结果表明,花生秸接种蚯蚓处理与不接种蚯蚓处理和油莱秸接种蚯蚓处理与不接种蚯蚓处理之间的土壤有效磷含量差异均达显著水平.采用Hedley磷素分级法测得的树脂磷由原土的痕量增加到10.5～17.8 mg·kg^-1,NaHCO₃溶解态磷由原土的14.5 mg·kg^-1增加到23.5～53.6 mg·kg^-1,微生物细胞磷由原土的1.0 mg·kg^-1增加到6.8～9.7 mg·kg^-1,土壤有机磷含量由原土的37.9 mg·kg^-1增加到50.7～59.3 mg·kg^-1,而土壤中活性最低的残留磷含量则有所降低.蚯蚓活动对红壤磷素具有较强的活化作用.     

Effects of arbuscular mycorrhiza and phosphorus application on arsenic toxicity in sunflower (Helianthus annuus L.) and on the transformation of arsenic in the rhizosphere

Effects of arbuscular mycorrhiza (AM) and phosphorus (P) application on arsenic (As) toxicity were studied in a rhizobox system with As-contaminated soil collected from Shimane Prefecture, Japan. The treatments consisted of a combination of two levels of AM (Glomus aggregatum) inoculation (−AM and +AM) and two levels of P application (−P and +P at 30 mg P kg⁻¹). Sunflower (Helianthus annuus L.) seedlings were cultured in rhizoboxes for 6 weeks. Rates of root AM infection in +AM treatments were about 40% regardless of P application. AM inoculation as well as P application reduced As toxicity symptoms, most clearly so in the +AM−P treatment. Plant growth was highest in the +AM + P treatment. Shoot As concentrations were slightly reduced by AM inoculation but enhanced by P application. Shoot P concentration in the +AM−P treatment was similar to that of +P treatments and was higher than in −AM−P. Analyses of rhizosphere soils at the end of the cultivation period indicated that P application increased water-soluble As (WS−As) in all compartments while AM inoculation increased WS−As in the central compartment only. Both the WS−arsenite [WS−As^(III)] and the dominant form, arsenate [WS−As^(V)], showed gradients toward the root surface. Dimethylarsine (DMAA) was detected in the +AM treatments only. To our knowledge, this is the first report of the occurrence of DMAA in the mycorrhizosphere. AM inoculation increased WS−P similarly as +P treatments did and promoted acid phosphatase activity in the soil. In conclusion, AM inoculation alleviated the effects of As toxicity by improving P nutrition without increasing As concentrations in the shoots. Moreover, AM appeared to be involved in the transformation of soil inorganic As into less toxic organic forms.     

Health risk assessment of arsenic in soils from three thermal power plants in Southwest China

Abstract

High levels of arsenic (As) contamination in soils from thermal power plants pose a great threat to human health. This study aimed to evaluate the As contamination levels and assess the possible health risk of As in soils from three typical thermal power plants in Southwest China. The concentration of As was detected by using novel collision/reaction cell technology (CCT) with inductively coupled plasma mass spectrometry (ICP-MS, collectively ICP-CCT-MS) after aseptic digestion of soil samples. The carcinogenic risk and hazard quotient were estimated for health risk to workers in the study area by using “Chinese Technical Guidelines for Risk Assessment of Contaminated Sites (HJ 25.3-2014)”. Results showed that the concentration of As was between 3.65 and 33.80?mg/kg, and the comprehensive carcinogenic risk level of As was 3–28 times over the maximum acceptable level (10^?6), indicating that workers in the study area are facing serious threat of As. Oral ingestion (76.65%) was the main exposure pathway to carcinogenic risk, followed by skin contact (13.15%) and inhalation of soil particles (10.20%). After calculating the safety threshold values under three different exposure pathways (oral ingestion, skin contact and inhalation of soil particles), the minimum safety threshold value (1.59?mg/kg) was selected as the reference safety threshold value of As in the study area. These results provide basic information of health risk assessment of As and environmental management in thermal power plant areas.     

Protective effect exerted by soil phosphorus on soybean subjected to arsenic and fluoride

Objetive: Arsenic (As) and fluoride (F) are found in groundwater and soils around the world, causing different problems to crops. Because these elements compete against phosphorus (P) in soils and plants, their relationship is complex. The aim of this work was to study the oxidative stress of soybean plants subjected to different concentrations of As and F, and the effect of P.

Methods: The following 10 treatments were carried out in each of two soils with different P content: three As levels (low 10?mg?As?kg^-1, medium 50?mg?As?kg^?1 and high 100?mg As kg^?1), three F levels (low 160?mg?F?kg^?1, medium 250?mg?F?kg^?1 and high 500?mg?F?kg^?1) and three As?+?F levels (same concentrations), and the control treatment (soil with the background As and F concentrations) Lipid peroxidation, chlorophyll, gluthatione contents and antioxidant enzymes activities were determination.

Results: Increased lipid peroxidation and alterations in glutathione content, catalase, superoxide dismutase and peroxidase activities as well as in chlorophyll content revealed that As causes higher oxidative stress in plants grown in soils with low P content.

Conclusion: Stress parameters in F treatments were less affected. Plants grown in soils enriched with P revealed a decrease in the toxic effects caused by As and F.     

Characteristics of molybdate-impregnated chitosan beads (MICB) in terms of arsenic removal from water and the application of a MICB-packed column to remove arsenic from wastewater

The removal of arsenic (As) species, such as As(III) and As(V), from water by molybdate-impregnated chitosan beads (MICB) in both batch and continuous operations was studied. The effects of pH, temperature, coexisting ions, and arsenic concentrations were studied in batch tests. Studies on the kinetic adsorption of MICB, the recovery of arsenic by the desorption solution, and the reuse of MICB were also carried out. The practicality and efficiency of an MCIB-packed column on arsenic removal were evaluated in a continuous system on industrial arsenic-containing wastewater discharged during the manufacture of GaAs supports. The results indicate that MICB favor the adsorption of both As(V) and As(III). The optimal pH value for As(III) and As(V) removal was 5. The adsorption of arsenic on the MICB is most likely an exothermic reaction. The effect of coexisting ions was varied and depended on their concentrations and species. The optimal desorption solution for arsenic recovery was 1M H2SO4, which resulted in a 95% efficiency for As(III) and 99% for As(V). In the continuous tests, the MICB-packed column exhibited excellent arsenic removal from wastewater without any pretreatment. These results provide strong evidence of the potential of MICB for removing As from industrial wastewaters.     

三峡水库香溪河库湾沉积物对磷的吸附特征研究

通过三峡水库香溪河库湾的3个采样点沉积物中磷的自然吸附实验和不同粒径下沉积物的胁迫吸附试验,研究了沉积物对磷的吸附特征。结果表明:上覆水中的磷浓度与沉积物中的总磷含量有很好的相关性,沉积物中的总磷含量对上覆水的水质有很大的影响;三点的临界平衡浓度为C1:0.188mg/L,C2:0.147mg/L,C3:0.188mg/L;各点增加的量即饱和吸附量不同(ΔQ1:268.16mg/kg,ΔQ2:57.96mg/kg,ΔQ3:267.27mg/kg),恰恰与三点的临界平衡浓度之间的关系一致;粒径对沉积物对磷的吸附量影响程度与沉积物理化参数也存在很大的关系;三个样点的吸附量,分别接近于1.5mg/g,0.8mg/g及1.4mg/g。结果还表明:最大吸附量大的地方,饱和吸附量不一定就大,二者之间不存在必然的关系;香溪河沉积物中的磷在现有条件下表现为“源”,不排除外在条件改变时转化为“汇”。如果最大吸附容量、饱和吸附容量及平衡浓度能够很好的与数学相结合,可为当地的环保部门管理香溪附近工厂提供科学依据。     

紫色土外源砷的形态分配与化学、生物有效性

采用盆栽试验与化学分析相结合的方法研究了外源As在酸性、中性、钙质紫色土中的形态分配及其化学、生物有效性特征.结果表明,土壤本底As68%～86%为残留态,外源As加入10d后50.2%～61.1%转化为残留态,至收获期(60d)仅增1%～2%.酸性紫色土中活性态As分配为:A(交换态)As>Al As>Fe As>Ca As;中性紫色土:A As>Al As>Ca As>Fe As;石灰性紫色土:A As>Ca As>Al As>Fe As.浸提剂HCl、NaHCO₃、NH₄Cl对土壤As的提取能力不同,与植物吸收As的相关性也有差异.NH₄Cl主要提取交换态As,对土壤As的原有形态影响最小,与植株吸收量呈极显著相关,可作为不同土壤有效As的通用浸提剂.多元回归表明,酸性紫色土决定植株吸As量的是Al As和Fe As,中性、石灰性紫色土为A As和Ca As.试验发现,Al As分级时存在F^-的干扰,1mol·L^-1H₃BO₃可有效掩蔽.     

Effect of algal growth on the availability of phosphorus,iron and manganese in rice soils

Summary Laboratory experiments were conducted to study the effect of algal growth on the change of (I) pH, (II) available phosphorus and (III) solubility of iron and manganese content in five waterlogged alluvial rice soils of West Bengal, India. The results showed that the algal growth initially caused an increase in the soil pH, which later declined to the original value in some of the soils. The available phosphorus content decreased upto 90 days of their growth and began to increase towards the later period of incubation. The drastic fall of water soluble plus exchaneable manganese content of the soils due to algal growth was accompanied by similar increase in reducible manganese content. No appreciable change in water soluble plus exchangeable ferrous iron content was encountered but theN-NH₄OAC(pH 3) extractable iron due to algal growth progressively decreased with the progress of the incubation period.     

配施磷细菌肥对复垦土壤细菌多样性及磷有效性的影响

为了解磷细菌肥对复垦土壤微生物群落结构变化特征和磷有效性的影响,本研究以连续配施磷细菌肥5年的定位试验为背景,利用16S rDNA基因序列测序方法对土壤细菌群落多样性进行分析,探讨土壤细菌群落与土壤Olsen-P、碱性磷酸酶的关系.试验共设对照、单施化肥、有机肥、有机肥化肥、化肥磷细菌肥、有机肥磷细菌肥和有机肥化肥磷细菌肥7个处理.结果表明: 复垦土壤中放线菌门和变形菌门菌群的相对丰度最大,分别为21.6％～32.2％和13.8％～28.9％.有机肥化肥磷细菌肥处理的OTU数和Chao1指数分别为809和26190,均属最高.磷细菌肥处理能提高土壤中放线菌门和变形菌门菌群的相对丰度,降低土壤中酸杆菌门、热袍菌门和硝化螺旋菌门菌群的相对丰度,对诺卡氏菌属、屈挠杆菌属有一定的促进作用.有机肥化肥磷细菌肥处理能够提高复垦土壤Olsen-P及碱性磷酸酶活性.复垦土壤变形菌门与Olsen-P、碱性磷酸酶的相关系数最高(0.900、0.955),在一定程度上可以作为土壤磷有效性的灵敏性指标.