土壤农残降解剂的作用和应用前景

一、土壤农残状况土壤是被重复利用的农业资源,一切生命都是从土壤开始。

在农田栽参中应用土壤农残降解剂

农田栽参是一种较为先进的栽培方式,有效地解决了参业与林业的矛盾。开发农田栽培人参,不仅对保护生态平衡有着重要的意义,还可以免除刨树根进行整地等繁重的体力劳动,有着明显的节本增效的作用。开发农田栽培人参,首先遇到的是由于盐类聚集而造成的土壤有害化学物质残留量过高和土壤板结两项不利因素。

GC-MS/MS在土壤农残检测中的应用研究

土壤农残一直是困扰我国农业发展的一大问题。土壤残留大量的化学农药不仅会威胁人们生命健康,还可能造成粮食作物减产。当前,GC-MS/MS因其简单操作、方便快捷、数据准确性高等特点在各大检测公司都应用甚广。因此,本文将通过分析GC-MS/MS本身的优势以及我国的农业现状来探讨GC-MS/MS应用于土壤农残检测中的必要性,进一步分析如何将GC-MS/MS运用到土壤农残检测之中,旨在为相关人员提供一定的借鉴。

Organophosphorus Pesticide Extraction and Cleanup from Soils and Measurement Using GC-NPD

The objectives of this study were to optimize instrumental parameters and conditions for analysis of selected organop- hosphorus pesticides (OPPs) by gas chromatography (GC) with nitrogen-phosphorus detection (NPD) (GC-NPD); to select an appropriate solvent system; to conduct a comparison of sonication and shaking extractions; and to select an appropriate procedure for extracting organophosphorus pesticides from soils. Procedure I consisted of n-hexane or petroleum ether together with acetone used as solvents, while Procedure contained several solvents including acetone, methanol, dichloromethane, and n-hexane or petroleum ether. Experimental results indicated that a mixture of petroleum ether/acetone (2:1, v/v) could be used in place of n-hexane/acetone (2:1, v/v) as it was a less expensive solvent system. In addition, shaking under a water bath at 20 °C was more effective than sonication. Also, Procedure I was more effective, safer, and more timesaving than Procedure Procedure I was applied to three soil types of different organic matter content, with recoveries of the OPPs from the yellow-brown soils, which had a higher organic matter content, being lower than those from the yellow and red soils.

Effects of Different Sowing Dates on Weed Suppression and Pesticide Residue in Soil

[Objective] To effectively suppress weeds and degrade pesticide residues in soil, pollution-free agricultural production is a very important way. [Method] In regions where high residual pesticides had been applied for a long term, 2-3 consecutive years of shallow ploughing after the autumn harvest, early shallow ploughing and sowing later in the next spring, and late ploughing and sowing were conducted,and the effects of the three measures on weed suppression and reduction of pesticide residue in soil were analyzed by measuring the length and fresh weight of crop radicles. [Result] Trifluralin applied in the A. membranaceus field for a long term limited the growth of the alfalfa seedlings. That is, the radicle length of each plant was 2.1-2.9 cm shorter than that of the control, and the fresh weight of each plant reduced by 0.19-0.20 g. Metsulfuron methyl applied in the alfalfa field for a long term also limited the growth of the alfalfa seedlings, that is, the radicle length of each plant was 1.9-2.0 cm shorter than that of the control, and the fresh weight of each plant reduced by 0.13-0.15 g. Shallow ploughing was conducted within two days after the autumn harvest, and all weed seeds on the ground were plowed into the plough layer 0-10 cm instead of deep soil. Early shallow ploughing in the next spring could make most seeds of weeds in surface soil sprout early, and sowing was conducted after 10 d, so that about 40% of weeds sprouting early were killed off. However, after shallow ploughing and sowing were conducted 10 d later than the normal sowing period, and around 30% of weeds were killed off. In addition,the weeds left in soil should be removed manually at the seedling stage or in late period. These measures had no adverse impact on the growth and development of crop radicles and yield. [Conclusion] In regions where pesticides with long-term residue had been applied for a long term, 2-3 consecutive years of shallow ploughing after the autumn harvest, different farming and sowing measures and artificia weeding could suppress weeds in the crop fields effectively, did not pollute soil environment, and promoted the degradation of pesticides left in soil.

Residual Characteristics of Organochlorine Pesticides in Lou Soils with Different Fertilization Modes

Soll samples with three fertilization treatments （no fertilizer, corn straw and farm manure） collected from a Lou soil （Eum-orthic Anthrosol classfied using Chinese Soil Taxonomy） in northwestern China were analysed for residual levels and their characteristics of organochlorine pesticides （α-HCH, β-HCH,γ-HCH, δ-HCH, HCB, o, p＇-DDT, p, p＇-DDT, o, p＇- DDE, p,p＇-DDE, p,p＇-DDD, α-endosulfan, dieldrin and endrin）. Organochlorine pesticides （OCPs） were detected in all soil samples except δ-HCH and their total concentrations ranged from 159.31 ± 9.00 to 179.77 ± 2.58 ng g^-1 with an order of HCHs 〉 DDTs 〉 （dieldrin ＋ endrin） 〉 HCB 〉 α-endosulfan. Among all the compounds, γ-HCH had the highest concentration followed by p, p＇-DDE. The residual levels of HCH isomers and DDT as well as their metabolites in soil with different fertilization treatments were in the order of γ-HCH 〉β-HCH ≈ α-HCH 〉 δ-HCH and p,p’-DDE 〉 p, p’-DDT 〉 o,p＇-DDT 〉 p, p＇-DDD ≈ o, p＇-DDE, respectively. DDE/DDT ratios ranged from 1.59 ± 0.13 to 3.35± 0.16 and endrin/dieldrin ratios from 1.40 ±0.06 to 9.20± 4.05, both indicating no new occurrence of these pesticides in these soils, while α-HCH/γ-HCH ratios of 0.04 indicated a new input of lindane （almost pure γ-HCH） in the past several years. The farm manure treatments showed lower DDT residues than samples without fertilizer. Also addition of corn straw and farm manure increased soil organic matter content and decreased the soil pH which could retard the degradation of DDT in the soil.

Residual Levels and New Inputs of Chlorinated POPs in Agricultural Soils from Taihu Lake Region

Selected persistent organochlorine pesticides (OCPs), including 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and its principal metabolites 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) and 1,1-dichloro-2,2-bis(p-chlorophenyl)e- thane (DDD), hexachlorocyclohexane (HCH) and its isomers (α-,β-, γ-, and δ-HCH), hexachlorobenzene (HCB), endo- sulfan, dieldrin, and endrin were quantified to determine current levels of organochlorine pesticides, to assess the eco- toxicological potential, and to distin…

Residues of Organochlorine Pesticides(OCPs) in Agricultural Soils of Zhangzhou City,China

A soil survey was conducted in Zhangzhou City, an important agricultural region in south of the Fujian Province, China. 93 surface soil samples were collected in the paddy fields, vegetable lands, orchards and tea plantations from Zhangzhou City. An additional soil profile was sampled in a paddy field as previous research had indicated high concentrations of organochlorine pesticides （OCPs） in the paddy fields. Dichlorodiphenyltrichloroethanes （DDTs） ranged from 0.64 78.07 ng g-1 dry weight and hexachlorocyclohexanes （HCHs） ranged from 0.72-30.16 ng g-1 dry weight in the surface soil of the whole study region. Ratios of a-HCH/-γ-HCH 〈 4 and o,p′-DDT/p,p′-DDT 〉 1 in all soil samples suggested that lindane and dicofol were widely applied in this region in the past. Concentrations of HCHs and DDTs in soils from the four land use types followed the orders： paddy fields 〉 vegetable lands 〉 tea plantations 〉 orchards and tea plantations 〉 orchards 〉 paddy fields 〉 vegetable lands, respectively. Analyses of the data showed no correlation （r 〈 0.1） between elevation and OCPs contents in paddy fields, orchards and vegetable lands, indicated no significantly different features in distribution of HCHs and DDTs in the soils from low lying plains and mountains and the unsystematic usage of OCPs, and highlighted the fragmented nature of agricultural production in Zhangzhou, as well as the reemission of OCPs from the soils, where high OCPs concentrations were found, in Longhai of Zhangzhou. In addition, no obvious relationship between the OCPs and total organic carbon （TOC） （r 〈 0.3） was observed in the soil profile. The mean contribution of dicofol in total DDTs was 66% in the whole Zhangzhou region. The approximate burdens of HCHs and DDTs in the surface layer of 0-20 em were 0.44 and 1.55 t, respectively. The storage of both HCHs and DDTs in soil surface layer （0-20 cm） accounts for 40% burden of the soil layer of 0 50 cm （1.10 t HCHs and 3.87 t DDTs）, in which the highest concentrations of OCPs were observed in soil profile.

Assessment, Composition and Possible Source of Organochlorine Pesticides in Surface Soils from rmqi, China

Twenty-eight surface soil samples from 5 functional zones （park, traffic roadside, business/residential area, rural area, and industrial area） of Uruimqi, China were collected and analyzed for the concentrations of 14 organochlorine pesticides （OCPs）, such as 3 isomers of hexachlorocyclohexane （HCHs） （α-HCH, β-HCH, and γ-HCH）, 4 dichlorodiphenyltrichloroethanes （DDTs） （p,p′-DDT and its metabolites p, p′-DDD （1,1-dichloro-2,2-bis（p-chlorophenyl）ethane） and p,p′-DDE （1,1-dichloro-2,2-bis（4-chorophenyl）ethylene）, and o, p′-DDT）, and methoxychlor, aiming to survey the residue levels and compositions of these 14 OCPs, to identify possible sources of the OCPs, and to assess their potential risks to human health and the environment in surface soils of Ur/imqi. The concentrations ranged from non-detected to 30.86μg kg^-1 for HCHs （sum of α-, β-, and γ-HCH）, from non-detected to 40.03 μg kg^-1 for DDTs （sum of p, p′-DDT, p, p′-DDD, p, p′-DDE, and o, p′-DDT）, and from non-detected to 11.95 μg kg^-1 for methoxychlor. The total concentrations of the OCPs ranged from 16.40 to 84.86 μg kg^-1, with a mean of 41.89 ± 16.25 μg kg^-1. According to the measured concentrations and occurrence rates of the 14 OCPs, DDTs, HCHs, and methoxychlor were the most dominant compounds. Among the 5 functional zones, the total concentration of OCPs was in the order of rural area 〉 traffic roadside 〉 park 〉 business/residential area 〉 industrial area. The different compositions of DDTs and HCHs indicated that the residues of these compounds in most soil samples originated from historical application, besides slight recent introduction at some sampling sites. The results of Pearson correlation analysis showed that soil total organic carbon played an important role in the residue levels of HCHs, but such relationships were not found with DDTs or other OCPs. The soil quality of Uriimqi was classified as Class I based on the guidelines of the Chinese Environmental Quality Standard for Soil （GB15618-1995）, indicating that the residue levels of OCPs have little risks to the environment and human health in the study area.