啤酒废水灌溉对6种蔬菜硝酸盐亚硝酸盐含量的影响

通过啤酒废水灌溉对６种蔬菜硝酸盐等的影响研究认为：啤酒废水灌溉对６种蔬菜灰分含量无明显影响,明显提高莴苣,马铃薯和甘蓝中维生素Ｃ的含量,提高韭菜,莴苣和甘蓝硝酸盐的含量;降低大葱硝酸盐的含量,可提高韭菜和马铃薯中亚硝酸盐的含量,而对于大葱、莴苣,小白菜和甘蓝中亚硝酸盐含量无明显影响。     

芜湖市蔬菜硝酸盐污染状况及安全处理效果

对芜湖市蔬菜集散市场的菠菜、青菜、黄瓜、青椒、番茄、马铃薯、莴苣、白萝卜、卷心菜及腌制雪里蕻10种常见蔬菜的硝酸盐含量进行了测定,并分析了低温储存及洗洁精清洗对蔬菜硝酸盐含量的影响。结果表明,洗洁精去除蔬菜中硝酸盐效果较好,常规洗菜前先在"白猫"牌洗洁精水溶液中浸泡15min,可使硝酸盐平均含量降低近100mg·kg-1。随着放置时间的增加,硝酸盐逐渐分解,而冰箱内低温存放,可减缓蔬菜硝酸盐含量的下降。根据GB18406.1—2001《农产品安全质量无公害蔬菜安全要求》对10种蔬菜进行的评价发现,叶菜类蔬菜中菠菜、青菜硝酸盐含量严重超标,其他所测蔬菜均未超标。     

临沂地区蔬菜主要有害物质的调查

通过对全区蔬菜地布点取样调查，探明了蔬菜中有害物质（硝酸盐、亚硝酸盐、重金属、六六六、ＤＤＴ）以及６种重金属的残留量。结果表明，硝酸盐类是该区蔬菜中的主要有害物质，所检测的３种蔬菜中，硝酸盐和亚硝酸盐的超标率分别为７８．３％和３３．６％；重金属含量大多数未超标；ＤＤＴ全部未检出；六六六超标率平均为４．３％。     

临沂地区蔬菜主要有害物质的调查

通过对全区蔬菜地布点取样调查，探明了蔬菜中有害物质（硝酸盐、亚硝酸盐、重金属、六六六、ＤＤＴ）以及６种重金属的残留量。结果，硝酸盐类是该区蔬菜中的主要有害物质，所检测的３种蔬菜中，硝酸盐和亚硝酸盐的超标率分别为７８．３％和３３．６％；重金属含量大多数未超标；ＤＤＴ全部未检出；六六六超标率平均为４．３％。     

离子色谱法同时测定蔬菜中的亚硝酸盐与硝酸盐

硝酸盐、亚硝酸盐广泛存在于人类环境中,其对人类健康和生态环境的危害,日益受到人们的普遍关注.硝酸盐在细菌的作用下可还原成亚硝酸盐,使血液的载氧能力下降,从而导致高铁血红蛋白症;另一方面,亚硝酸盐可与次级胺（仲胺、叔胺、酰胺及氨基酸）结合,形成亚硝胺,从而诱发消化系统癌变.而人体摄入的硝酸盐81.2%来自蔬菜.因此,蔬菜中硝酸盐和亚硝酸盐含量的高低已成为衡量蔬菜安全与否的一项重要指标,我国已对无公害蔬菜中的亚硝酸盐和硝酸盐含量提出明确的限量标准.……     

珠江三角洲典型地区蔬菜硝酸盐与亚硝酸盐污染评价

研究了珠江三角洲典型地区中山市大型蔬菜生产基地中9种蔬菜30个样品中硝酸盐与亚硝酸盐的污染现状,初步摸清了蔬菜中硝酸盐及亚硝酸盐的污染状况。并以WHO/FAO规定的日允许摄入量换算得到的标准评价了其主要蔬菜品种的硝酸盐污染状况。结果表明:在被调查的蔬菜中,硝酸盐含量由高到低依次为菜心→白菜>芥菜→空心菜→生菜→瓜果类,菜心、芥菜和白菜为严重污染,生菜与空心菜为重污染,瓜果类蔬菜为轻污染;亚硝酸盐含量普遍较低,均未超标。因而有必要采取有效的污染防治措施控制该地区蔬菜中的硝酸盐污染状况。     

广东省典型地区蔬菜硝酸盐与亚硝酸盐污染状况评价

研究了广东省西翼的湛江市、珠江三角洲地区的东莞市、惠州市、中山市、珠海市和佛山市顺德区等典型地区大型蔬菜生产基地中4种蔬菜148个样品中硝酸盐与亚硝酸盐的污染现状。采用国家标准(GB18406.1—2001)进行评价,在所检测的蔬菜样品中,有36.5%样品的硝酸盐含量超标,亚硝酸盐含量相对较低;以WHO/FAO规定的日允许摄入量换算得到的标准评价蔬菜的硝酸盐污染状况,污染程度严重的蔬菜样品占62.2%,中、重度污染的占16.9%,轻度污染的占20.9%。蔬菜中硝酸盐含量由高到低依次为叶菜类>瓜类>豆类>茄果类。因而有必要采取有效的污染防治措施控制该地区蔬菜中硝酸盐污染状况。     

广东省蔬菜硝酸盐含量的调查与分析

为了解广东省蔬菜硝酸盐含量状况,分别对阳山、番禺、深圳等蔬菜生产基地和深圳市各流通领域中蔬菜的硝酸盐含量进行跟踪调查。结果表明,广东省蔬菜生产基地的蔬菜硝酸盐含量超标严重,特别是市民食用量较大的几种叶类蔬菜超标最为明显。定点监测结果表明,蔬菜的硝酸盐含量与蔬菜的新鲜程度呈明显的正相关,蔬菜越新鲜其硝酸盐含量越高;在2次定点监测中,蔬菜硝酸盐平均含量都呈现出如下的趋势:生产基地的>批发市场的>超市和农贸市场的。     

中国蔬菜硝酸盐和亚硝酸盐污染机制及控制对策

综述了近十几年来我国城市蔬菜中硝酸盐和亚硝酸盐污染的调查结果,表明随着氮肥使用量的增大,蔬菜中硝酸协污染为严重,而亚硝酸盐污染也不容忽视。探讨了蔬菜受硝酸盐和亚硝酸盐污染的影响因素及控制对策。     

有机无机肥配合施用对菜园土壤及蔬菜硝酸盐类动态的影响

通过田间小区试验和室内测定,研究了有机肥与化肥以不同比例配合施用对小白菜硝酸盐和亚硝酸盐含量以及土壤硝酸盐含量的影响。结果表明:有机肥与化肥配合施用可以明显降低小白菜硝酸盐含量,减少硝酸盐在土壤剖面中向下淋溶,尤以有机肥与化肥施用比例为1∶1(质量比)时小白菜产量较高,体内硝酸盐含量较低,土壤下层的硝酸盐含量也较低,达到蔬菜高产优质,生态环境清洁健康的目标。     

Applications of chitosan in food,pharmaceuticals, medicine,cosmetics, agriculture,textiles, pulp and paper,biotechnology, and environmental chemistry

Environmental Chemistry Letters - Chitosan is a biopolymer obtained from chitin, one of the most abundant and renewable materials on Earth. Chitin is a primary component of cell walls in fungi, the...     

Metal passivity as mechanism of metal carcinogenesis: Chromium,nickel, iron,copper, cobalt,platinum, molybdenum

For the transition metals chromium, nickel, iron, copper, cobalt, platinum, and molybdenum, mechanisms of stable bonding in biochemistry (emphasis on carcinogenic mechanisms), chemistry, industrial chemistry, as well as epidemiological, occupational, orthopedic (implant devices) effects related to carcinogenesis, were reviewed. Hypothetically, the propensity to stable bonding (inertness), which ensures the metals’ performance capacity for consumers and industrial application, relates to their carcinogenicity. For chromium, a relationship between industrial/chemical and biological reactivity was noted for the tendency of Cr(III) ions to cause hydrolysis previous to stable bonding, as occurs during anodic passivation, leather tanning, and as indicated in biochemical studies pertaining to a mechanism of DNA condensation, which was suggested as a carcinogenic mechanism. The involvement of metal hydrolysis in both anodic passivation and biochemistry was noted also for nickel, iron, and platinum; the DNA interaction of platinum (cis-platin) is known to depend on hydrolysis. For nickel, issues of potential (V) were found important in both passivation and carcinogenicity. Comparably, the passivity behavior of cobalt and copper was found atypical, and their carcinogenicity yet unclear. Molybdenum, contained in passivated metallic implants, may relate to implant-associated carcinogenesis. Occupational carcinogenic effects were indicated for chromium, nickel, iron, and cobalt as caused by both reactive and passivated metal species. Exposure to acids and chronic respiratory irritation/infection/inflammation in workers were important cofactors in metal carcinogenesis. For wood and leather workers exposed to dust, the assumed presence in dust of metal particles abraded from alloys (sawing or cutting blades) may be a carcinogenic exposure hazard.     

Lead,cadmium, copper,zinc, iron,and calcium in human hair as a function of gender,age, smoking,and hair dyeing

Hair samples were collected randomly from 110 subjects (55 male and 55 female) ranging in age from (<15–60) years. Each subject was asked to complete a personal questionnaire describing his/her sex, age, general health, smoking, use of hair dyes, occupational area, and living habits. Concentrations of Pb, Cd, Cu, Zn, Fe, and Ca in human hair samples were evaluated using atomic absorption spectrometry. Results indicated that concentrations of Pb, Cd, Cu, and Zn in the hair of smokers were higher than those in the hair of non-smokers, whereas, Fe and Ca concentrations in hair of smokers were lower than those in hair of non-smokers. Moreover, the concentrations of these elements are higher in dyed hair compared with undyed hair.     

Fragmentation of Phragmites Habitats, Minimum Viable Population Size, Habitat Suitability, and Local Extinction of Moths, Midges, Flies, Aphids, and Birds

Results from populations of insects and birds inhabiting Phragmites habitats were used to analyze effects of fragmentation. Flush-crash cycles of the stem-boring moth Archanara geminipuncta (Lepidoptera, Noctuidae) showed regionally concurrent, local extinctions despite an originally enormous population size (more than 180,000 adults), emphasizing the importance of metapopulation dynamics. Further, A. geminipuncta could be considered a keystone species, since shoot damage facilitated more than twenty species of herbivores, saprovores (of the caterpillars' feces), and their parasitoids. The gall midge Lasioptera arundinis could survive only in side shoots induced by shoot damage of A. geminipuncta .
Small Phragmites stands had thinner shoots (due to a water or nutrient deficiency) and shoots with more leaves (due to a better light supply) than large stands, thereby influencing species-specific demands for habitat suitability and nutritiousness of reed tissue. In other words significance of habitat fragmentation could not be assessed by area alone. For example, two chloropid flies depending on thin, yellowish shoots survived only in small habitats or in the unmown edges of large habitats.
Local persistence of Phragmites herbivores depended on much larger population sizes than could be expected from a population size sufficient to maintain genetic variation. At least 11,000 adults of the gall midge Giraudiella inclusa (or more than 84,000 galls) were necessary to avoid local extinction.
With regard to conservation management of reed habitats, nature reserves should consist of old and unmown reeds, have fewer disturbed (particularly, fewer mown) habitat edges, measure more than two hectares (priority should go to the largest remaining fragments), and be surrounded by nearby reed habitats providing reservoir populations and diverse shoot types.     

Research progress on distribution,sources, identification,toxicity, and biodegradation of microplastics in the ocean,freshwater, and soil environment

• Microplastics are widely found in both aquatic and terrestrial environments. • Cleaning products and discarded plastic waste are primary sources of microplastics. • Microplastics have apparent toxic effects on the growth of fish and soil plants. • Multiple strains of biodegradable microplastics have been isolated. Microplastics (MPs) are distributed in the oceans, freshwater, and soil environment and have become major pollutants. MPs are generally referred to as plastic particles less than 5 mm in diameter. They consist of primary microplastics synthesized in microscopic size manufactured production and secondary microplastics generated by physical and environmental degradation. Plastic particles are long-lived pollutants that are highly resistant to environmental degradation. In this review, the distribution and possible sources of MPs in aquatic and terrestrial environments are described. Moreover, the adverse effects of MPs on natural creatures due to ingestion have been discussed. We also have summarized identification methods based on MPs particle size and chemical bond. To control the pollution of MPs, the biodegradation of MPs under the action of different microbes has also been reviewed in this work. This review will contribute to a better understanding of MPs pollution in the environment, as well as their identification, toxicity, and biodegradation in the ocean, freshwater, and soil, and the assessment and control of microplastics exposure.     

Fractionation of trace metals (Mn,Zn, Cu,Pb) in Red Sea sediments,Gulf of Aden,Yemen

A sequential extraction technique was applied to estimate the chemical association of Mn, Zn, Cu and Pb in five chemical phases (exchangeable, carbonate, Fe–Mn oxides, organic matter and residual) in sediments of the Gulf of Aden, Yemen. The results indicated that a higher level of Mn was associated with the residual fraction (natural sources) than the non-residual fraction (anthropogenic sources). Zn fractionations revealed that it was associated more with Fe–Mn oxides and organic fractions than exchangeable and carbonate fractions. Most of the Cu was present in the residual form (60–72%) except for in the main port area (zone III), where it was associated with the organic phase (77% of the total Cu content, the organic matter content was 5%). Similarly, most Pb was bound in the residual fraction (56–71%) except the main port area where ～ 62% of the total Pb was bound in non-residual fractions. It was also found that the Pb concentration in the exchangeable fraction was very high compared with other metals. The risk assessment code for the metals showed a low risk for Zn and Cu, but low to medium risk for Mn. Fractionation of Pb showed medium risk at most of the regions except at the eastern area, which revealed a high risk for the aquatic environment.     

Fractionation of Mn, Fe, Zn and Cu in Sediments of Khor Kalabsha, Lake Nasser, Egypt

Khor Kalabsha is the second largest Khor in Lake Nasser, which is a freshwater side-branch of the main lake. Chemical analysis of the samples indicates that calcium carbonate and organic matter content in the surface sediments average 17.8 and 3.07%, respectively. Moreover, manganese, iron, zinc and copper concentrations are lower in Khor Kalabsha than in other lakes of Egypt. It has been found that both oxides and residual forms constitute the major part of the measured elements in the study area, while manganese and iron play an important role in building up clay minerals. It is noted that both zinc and copper fractions are controlled by biological and biochemical processes.