Human health effects of dust exposure in animal confinement buildings

Work in swine and poultry units is associated with exposure to significant levels of organic dust and endotoxins with the highest concentrations found in poultry houses, whereas values found in dairy and in cattle farming are much lower. Corresponding to this is an excess of work-related respiratory symptoms in swine farmers. A dose-response relationship exists between symptoms and number of working hours. Longitudinal studies have demonstrated an accelerated decline of lung function in swine farmers large enough to cause clinically significant disease in some farmers. Because of the large number of people needed in swine farming and the long working hours, swine farming has emerged as the major respiratory problem in farming. Experimental studies indicate that exposure has to be lowered substantially to avoid acute effects and longitudinal studies demonstrate that loss of lung function occurs in non-smoking swine farmers without respiratory symptoms and that accelerated decline in lung function occurs below endotoxin concentrations in dust (100 ng/m3) proposed as a safe threshold.     

Temporal variation of indoor air quality in an enclosed swine confinement building

Human health hazards can exist in swine confinement buildings due to poor indoor air quality (IAQ). During this study, airborne dust and ammonia concentrations were monitored within a working farrowing facility as indicators of IAQ. The purposes of this study were to assess the temporal variability of the airborne dust and ammonia levels over both a daily and seasonal basis, and to determine the accuracy of real-time sensors relative to actively sampled data. An ammonia sensor, aerosol photometer, indoor relative humidity sensor, and datalogger containing an indoor temperature sensor were mounted on a board 180 cm above the floor in the center of a room in the facility. Sensor readings were taken once every 4 minutes during animal occupancy (3-week intervals). Measurements of total and respirable dust concentrations by standard method, aerosol size distribution, and ammonia concentrations were taken once per week, in addition to temperature and relative humidity measurements using a thermometer and sling psychrometer, respectively. Samples were taken between September 1999 and August 2000. Diurnal variations in airborne dust revealed an inverse relationship with changes in indoor temperature and, by association, changes in airflow rate. Ammonia levels changed despite relatively stable internal temperatures. This change may be related to both changes in flow rates and in volatility rates. As expected, contaminant concentrations increased during the cold weather months, but these differences were not significantly different from other seasons. However, total dust concentrations were very low (geometric mean = 0.8 mg/m3) throughout the year. Likewise, ammonia concentrations averaged only 3.6 ppm in the well-maintained study site.     

Quantitative colorimetric method for sulfamethazine in swine feeds

Sulfamethazine (SM) in swine feeds is quantitated colorimetrically by using a relatively simple procedure. The drug is isolated from an extract of feed by trapping it on a small bed of anion-exchange resin buffered at pH 7.9 following the removal of possible interfering compounds by pre-columns. SM is then eluted, diazotized, and coupled using the Bratton-Marshall reagents. The intensity of color developed is determined spectrophotometrically at 540 nm and the concentration of SM is calculated using a molar absorptivity of 52 500. Feeds containing from 1 to 130 ppm can be analyzed with very good accuracy and precision. The method has satisfactory specificity, is inexpensive, and can be applied to a relatively large number of samples per day. A simple and safe method for preparing N1-methyl SM at the low microgram level is described together with a thin layer chromatographic system for tentatively verifying the presence of SM in the feed both as the underivatized drug and as N1-methyl SM.     

猪场VOCs特征及减排技术研究进展

挥发性有机化合物（volatile organic compounds, VOCs）是大气污染物的重要组成成分，对环境和人体健康有潜在危害。生猪养殖业是畜牧业的支柱产业，但其发展受到猪场排放的VOCs等引起的空气污染严重制约。该研究从特征和减排技术两个方面对猪场的VOCs进行综述，重点介绍了猪场VOCs的来源、种类及其特征、致臭性VOCs的特征和检测方法等，从源头减排、过程控制与末端处理 3 个环节对猪场VOCs减排技术进行分析和探讨，并对该研究领域的发展趋势与研究重点进行展望，以期为开展畜牧业VOCs污染减排技术研究和推动畜牧业可持续发展提供参考。     

Evaluation of cement kiln flue dust as a potassium and sulfate fertilizer

Abstract

The main objective of this study was to determine the efficacy of cement kiln flue dust as a substitute for potassium sulfate fertilizer. Chemical and X‐ray diffraction analyses revealed that the flue dust contained about 20.7% K of which 9.1% was present as aphthitalite (K₃Na(SO₄)₂) , 4.4% as sylvite (KCl) and the remaining 7.2% as arcanite (K₂SO₄) . Accordingly, about 80% of the potassium in the dust was present as sulfates, though it contained 30% total sulfate and 15% Ca.

The effects of flue dust were compared to some or all of the following fertilizers: KCl, K₂SO₄ and a synthetic fertilizer, on 11 soils ranging in texture from sand to clay in three greenhouse experiments. The synthetic fertilizer was made from K₂SO₄ and CaSO₄.2H₂O which were applied at the same rate of K and Ca as contained in the flue dust. The experimental results show that flue dust is as effective a K source as any of the fertilizers tested as it increased potato, barley and alfalfa yields and tissue and soil K concentrations to the same level. Furthermore, the flue dust increased the tissue sulfur concentration and the quantities of available sulfate in soils to the same level as potassium sulfate. Finally, the Ca contained in flue dust increased the concentration of this element in potato tops and soils when grown on eight coarse textured soils. The flue dust had, however, no effect on soil pH on any of the soils tested.     

The respiratory inflammatory response to the swine confinement building environment: the adaptation to respiratory exposures in the chronically exposed worker

Swine confinement facility workers often develop respiratory problems secondary to their work, including the asthma-like syndrome, exacerbation of underlying asthma, chronic bronchitis, and mucous membrane irritation syndrome. Organic dust toxic syndrome is seen in these workers as well. Swine confinement barns are characterized by the presence of multiple factors that can cause respiratory tract and systemic inflammation symptoms, including dust, endotoxin, and ammonia. Investigators have found evidence of inflammation characterized by increased numbers of neutrophils, macrophages, and to a lesser degree, lymphocytes in both na?ve subjects and swine confinement building workers. Interestingly, this inflammation is most pronounced in subjects with no prior exposure to this environment. This finding suggests that adaptation or tolerance to endotoxin or other substances in this environment is induced by repeated exposures. Interventions have been devised to reduce the risk of symptomatic respiratory disease from working in a swine confinement facility. The efficacy of several of these interventions was tested using objective measures of respiratory tract inflammation. Recent finding suggests that such studies should be done in swine confinement workers if they appear promising using testing of na?ve subjects exposed to this environment.     

Vegetable oil stability at elevated temperatures in the presence of ferric stearate and ferrous octanoate

The thermoxidative stability of partially hydrogenated soybean oil (PHSBO) was examined after addition of ferric stearate and ferrous octanoate, and then heating the samples at 120, 160, 180, and 200 degrees C. In a second experiment, the effect of iron concentration (ferric stearate) on PHSBO stability was examined at 180 degrees C, and at concentrations of approximately 0.5 and 1.2 mg of added iron/kg PHSBO. Oil samples were heated continuously for 72 h and sampled every 12 h. The acid value, p-anisidine value, color, dielectric constant and the triacylglycerol polymer content of oil samples were compared to oil samples containing no added iron. Generally, the value of each oxidative index increased with (1) an increase in temperature, (2) an increase in heating time, and/or (3) an increase in iron. The results demonstrate that low concentrations of iron will substantially increase the rate of oxidation for vegetable oil samples heated to temperatures of 120 degrees C to 200 degrees C.     

Ecology of nematophagous fungi: Comparison of the soil sprinkling method with the Baermann funnel technique in the isolation of endoparasites

A comparative investigation has shown the Baermann funnel technique to be significantly more effective in isolating endoparasitic nematophagous fungi than the soil sprinkling method. However, the Baermann funnel technique was not able to isolate all the endoparasites present in a soil sample, and in 34.4% of the infected sites examined, extra data on species distribution was obtained using the soil sprinkling method. The results indicate that the Baermann funnel technique is influenced by the indigenous nematode population density.     

不同通风方式下猪舍病毒颗粒分布的数值研究

为了研究不同通风方式对猪舍内病毒颗粒分布的影响,本文利用离散轨道模型模拟病毒颗粒的轨迹,并与模拟气流运动的标准k-ε湍流模型相耦合的方法,对猪舍的横向、纵向2种通风方式的气流运动以及病毒颗质量粒浓度分布与排除进行数值研究。结果表明,在相同的送风量、压力条件和颗粒特性下,横向通风案例方案对比纵向通风有更好的控制病毒颗粒扩散的能力,然而纵向通风方式有更好的排污效率,能够使更多的颗粒逃逸、颗粒悬浮更少,但有更多颗粒沉积,会引起二次污染。2种方式在不同的角度有各自的优点,从防止病毒扩散,控制病毒的交叉感染角度来讲,横向通风方式能够对病毒颗粒有很好的控制作用,形成更均匀的气流,而纵向通风方式会使病毒颗粒在舍内进行大范围的扩散,容易产生交叉感染,因此横向通风方式更有优越性。     

Airborne antibiotic concentrations in a swine feeding operation

During the past 50 years, it has become common practice in the U.S. to add antibiotics to livestock feed to reduce disease and promote growth. Use of antibiotics in this manner has become the source of increasing controversy because overuse of antibiotics is suspected of leading to resistance in bacteria that cause human diseases. The purpose of this study was to measure airborne antibiotic concentrations in a swine production facility that routinely included antibiotics in feed. Samples were collected in a hog facility that included rooms devoted to farrowing, nursery, and growing operations. Analytical methods were developed to measure concentrations of the antibiotics tylosin and lincomycin in air samples. Tylosin was mixed in the feed in some of the rooms in the facility. While lincomycin was not added during this study, it had been used in this facility in the past and therefore was included in the analytical testing. Inhalable (n = 34), respirable (n = 37), and high-volume (n = 16) dust samples were collected on PVC filters over a two-month period. Tylosin concentrations were above the limit of quantification (LOQ) in 93% of the samples, while lincomycin concentrations were above the LOQ in only 9% of the samples (LOQ = 0.04 ng/sample). The average tylosin concentrations were 3, 18, and 49 ng/m3 in the respirable, inhalable, and high-volume samples, respectively. No occupational or environmental worker exposure criteria currently exist for antibiotics in air. The results of this study may be used to estimate potential swine production worker exposures and to further study the association between these exposures and health effects.     

Metal content and physicochemical parameters used as quality criteria in virgin argan oil: influence of the extraction method

Metal content was determined in 26 samples of virgin argan oil from Morocco. An ETA-AAS with previous sample dilution with MIBK technique was used. In oil obtained by traditional method, Fe ranged from 0.8 to 4.0 mg/kg, Cu from 160.4 to 695.7 microg/kg, Cr from 10.3 to 55.3 microg/kg, Mn from 18.1 to 70.8 microg/kg, and Pb from 28.5 to 450.0 microg/kg. In oil obtained by a half-industrialized method, Fe ranged from 0.8 to 1.7 mg/kg, Cu from 158.4 to 385.0 microg/kg, Cr from 10.0 to 48.1 microg/kg, Mn from 15.0 to 68.5 microg/kg, and Pb from 32.0 to 100.0 microg/kg. Acidity value, peroxide index, K270 and K232, humidity and sludge volatile, and insoluble sludges in petroleum ether were also determined. A high variability in these quality parameters and a decrease of the quality in the oils obtained by the traditional method were observed.     

Phosphate interference in the Devarda's alloy reduction method for nitrate

Abstract

Phosphate interfered markedly with a Devarda's alloy distillation method for the determination of nitrate. Only 9% of added nitrate was recovered by this method when 200 mg P was present. This interference can be overcome by the addition of calcium ions, to precipitate the phosphate, and an extended distillation time.     

Application of the acetylene reduction method in nitrogen fixation studies

The fixation of atmospheric nitrogen by organisms has usually' been measur'ed by the increase in t6tal nitrogen using the Kjeldahl method and, recently, by enriching with ¹⁵N isotope using a mass spectrometer after a suitable period of incubation. However, the Kjeldahl method is in accurate, laborious and not sensitive. The isotope UN method is 30 to 100 times more sensitive than the Kjeldahl method, but it is expensive and requires that the experiment is conducted only on a small scale, creating conditions quite different from the natural environment. The method also requires a mass spectrometer. More recently, DILWORTH (1) and SCHOLLHORN and BURRIS (2) observed that acetylene is reduced to ethylene by extracts from Clostridium pasteurianum. Ethylene production in the acetylene-reducing function of nitrogen-fixing microorganisms was determined by gas chromatographic techniques. The acetylene reduction method has been used in the detection of nitrogenase in biological systems (3,4,5,6). The method is reported to be simple, economical and a thousand times more sensitive than the liN method (6). This paper is a preliminary report on the use of the acetylene reduction method in studies on nitrogen fixation of various kinds of materials in the rice fields.     

长沙市蔬菜地土壤有效养分的空间变异性分析

在长沙市宁乡超大蔬菜基地,以面积为239.5 hm2的蔬菜地为试验区,随机采集了329个土壤耕层(0~20 cm)样品,应用地统计学分析了土壤铵态氮、硝态氮、有效磷的空间变异特征,并应用克里格插值方法绘制了土壤三种有效养分的空间分布图。为了使数据更好地符合正态分布,我们对它们进行了logit转化。通过趋势分析,我们发现铵态氮不存在明显的空间趋势,硝态氮和有效磷存在二阶空间趋势。地统计分析结果表明,数据经logit转化和必要的趋势去除后,铵态氮和硝态氮表现为中等空间自相关性,有效磷表现出较强的空间自相关性。铵态氮的半方差函数图符合Matérn模型,硝态氮和有效磷的半方差函数图符合Stein的Matérn模型。它们的变程分别为144 m、592 m、168 m。研究区铵态氮空间分布破碎化程度较高,硝态氮和有效磷的空间分布具有明显的阶梯状趋势。     

规模养猪场沼气工程清洁发展机制的温室气体减排效益

为了探讨碳交易市场对养殖场沼气工程赢利性的影响,该文选取位于太湖流域江苏省的3个不同规模的养猪企业为研究对象,通过清洁发展机制CDM(clean development mechanism)方法首先计算其沼气工程减少温室气体排放的效果,然后运用成本收益方法测算不同情境下项目的盈利能力。研究结果表明:规模化养猪场沼气工程的减排效果明显,3家养猪企业减排量分别为5 236.95,4 016.95和1 333.93 t,减排比率超过55%。但是在现有条件下,3家企业的沼气工程都处于亏损状态。在政府补贴、可再生能源发电收入和停交排污费的情况下,只有规模最大的A企业的沼气工程可以盈利。如果能够进入碳交易市场,且价格达到50元/t以上,3家企业的沼气工程都能实现盈利。推进沼气工程发电上网,碳减排进入碳交易市场,将明显改善沼气工程盈利能力,实现可持续发展,从而充分发挥节能减排的功能。     

Willow stands as an alternative method for the reduction of leachate at contaminated sites — numerical investigations

The commonly used multiple‐liner‐system of modern top sealings of contaminated sites is expensive and in many cases (minor hazardousness of pollutants), not necessary. As an alternative, we investigated the performance of willow stands as the only measure to reduce percolating soil water and therewith pollutant transport to underlying ground water resources. It is well accepted that willows have a high water demand and may considerably reduce percolation. On the basis of experimentally determined soil physical properties of a landfill site, we performed water balance calculations with the physically based HYDRUS‐code and a simple bucket approach. The 20 yr annual leachate rate for bare soil was calculated to vary from 336 (HYDRUS) to 451 mm yr^—1 (bucket‐model). Willows were able to reduce the annual leachate to 146 (HYDRUS) and 186 mm yr^—1 (bucket‐model), indicating their great performance compared to a grass‐ or beechwood cover. However, legal regulations (TASi) in Germany cannot be met with the proposed method. In minor hazardous cases, official authorities may accept willow stands as an alternative system for protection.     

Spectrophotometric determination of pyrantel tartrate in swine feeds by method of standard additions: collaborative study

The spectrophotometric method for pyrantel tartrate in swine feeds was collaboratively studied. Twenty-seven laboratories assayed feeds containing 0.0103, 0.0965, and 0.7902% pyrantel tartrate. Repeatability (sigmao) and reproducibility (sigmax) standard deviations were: sigmao = 0.00068%, sigmax = 0.00105% (10% of grand mean) for 0.0103% pyrantel tartrate level; sigmao - 0.0065%, sigmax = 0.0090% (10% of grand mean) for 0.0965% pyrantel tartrate level; and sigmao = 0.0415%, sigmax = 0.0743% (10% of grand mean) for 0.7902% pyrantel tartrate level. The mean theoretical recovery values for feeds containing 0.0103, 0.0965, and 0.7902% were 100, 97, and 96%, respectively. The method was adopted as official first action for feeds or concentrates containing 0.0106-0.8811% pyrantel tartrate.     

Use of shoot reduction treatments as a means of simulating hail injury to proso millet

Abstract

Proso millet, Panicum miliaceum (L.), is a warm‐season annual grass well adapted for grain production in the western Great Plains of the United States, where risk of hail injury is greater than any other region of the United States. Because adjustment procedures and loss equations are not available, proso millet producers in this region have had limited access to crop hail insurance as a risk management tool. Our research was conducted to assess impact of shoot reduction treatments imposed at different crop growth stages on grain yield loss of proso millet grown under several environments. Our goal was to provide information for development of crop insurance adjustment procedures. We also wanted to determine the impact of shoot reduction on various grain yield components. Treatments consisted of a control and three levels of shoot reduction (33,66, and 100% of full stand) applied at four growth stages (emergence, 4‐leaf, boot, and heading stages). The experiments were conducted at two locations (Akron, CO and Carrington, ND) during 1996 and 1997 to assess treatment impact on relative grain yield (RGY), expressed as percent of control. A significant shoot reduction χ growth stage interaction was observed for RGY, indicating yield loss from increasing shoot reduction varied with growth stage. A linear reduction in RGY to increasing levels of shoot reduction was observed for the 4‐leaf, boot and heading growth stages, while RGY displayed a segmented linear response to increasing shoot reduction at emergence. Variation in grain yield, induced by shoot reduction treatments, was more consistently correlated with variation in seed number than seed weight.