Minimizing contamination hazards to waterbirds using agricultural drainage evaporation ponds

In much of the San Joaquin Valley, California, USA, inadequate drainage of applied irrigation water and accumulating salts in the soil have necessitated the installation of subsurface tile drainage systems to preserve crop productivity. At present, these subsurface drainage waters are disposed of by means of evaporation ponds or discharges into the San Joaquin River. Unfortunately, most of these agricultural drainage waters contain high concentrations of salts and naturally occurring trace elements, such as selenium, and recent evidence indicates that substantial numbers of waterbirds are exposed to contamination by selenium in the evaporation ponds. In order to avoid, minimize, or mitigate the adverse impacts on wildlife using the ponds, alternative pond management methods must be identified and evaluated for implementation. A number of methods have the potential to be cost-effective in significantly reducing the contamination hazard to birds using agricultural evaporation ponds. Twenty general methods were evaluated in this study, and four methods are recommended for implementation: remove levee vegetation, remove windbreaks, deepen the ponds, and haze birds. A number of other methods are recommended for further consideration because they appear to have good prospects for reducing the contamination hazard: steepen interior levee slopes, apply herbicides and insecticides, place netting on pond shorelines, and provide freshwater habitat adjacent to evaporation ponds. It may be necessary to use a combination of methods to effectively control selenium contamination of aquatic birds because it is unlikely that a single affordable pond management method will be able to entirely eliminate the contamination hazard.     

环境中五氯酚监测研究进展

本文概述了五氯酚(PCP)的环境污染、人群暴露水平及目前有关监测方法研究进展。环境污染主要来源于本品的生产及工农业中的应用。在我国主要广泛用于杀灭血吸虫的中间宿主——钉螺。人体通过污染的空气、水体及食品可摄入PCP造成生物蓄积,危害健康。监测方法有化学法、紫外分光光度法、色谱法、极谱法、电化学检测法等,其中,色谱法简单、灵敏,易于普及使用。     

Lime as the source of PCDD/F contamination in citrus pulp pellets from Brazil and status of the monitoring program

After an exhaustive investigation, in 1997 the source of the milk contamination in Germany was traced to citrus pulp pellets originating from Brazil. It has been shown that lime was the source of the PCDD/F contamination of these products. After this conclusion, a continuous monitoring program has been performed over a two year period and the results are presented in this paper. Standard isotope dilution techniques were used for all samples, which were analyzed by selected ion monitoring high resolution GC–MS.     

Detection of indoor PCB contamination by thermal desorption of dust. A rapid screening method?

Although PCB in caulking materials has been forbidden for many years in most of Europe, including Denmark, there has been continued interest to measure PCB levels in the air of contaminated buildings and blood of the occupants (Mengon and Schlatter 1993, Fromme et al. 1996, Ewers et al. 1998, Currado and Harrad 1998, Gabrio et al. 2000). The relatively low priority for investigations of this contamination is probably due to the small quantities inhaled compared to exposure via food, and the rapid metabolism of the most volatile congeners demonstrated by low concentrations of all congeners in the blood of exposed persons (Ewers et al. 1998, Gabrio et al. 2000). There is, however, evidence that PCB containing caulking materials have been used even during the '90s (Fromme et al. 1996). In Denmark, it is estimated that 75 t PCB is still in buildings (Organization of Sealant Branch's Manufacturers and Distributors 2000). During an investigation of dust from buildings with excessive microbial growth (including 35 rooms from 9 buildings), the analysis of semivolatile compounds by thermal desorption-GC/MS of samples from a single building surprisingly revealed large amounts of PCBs containing 3, 4 and 5 chlorine atoms, 10-20 times the amounts found in samples from other buildings. Extraction of the dust by SFE followed by GC/ECD analysis for 12 PCB congeners showed that there was approximately 20 times the total PCB concentrations in dust from the polluted building compared to the levels in the other buildings. Subsequent headspace analysis of caulking material from the polluted building revealed this to be the source. Shelf dust functions as a passive sampling medium and, thus, can be used as a screening method to detect PCB and other semivolatile pollution indoors.     

Dietary habits associated with the presence of organochlorine pesticides in human milk

Abstract

This study aims to establish the relationship between the consumption of certain foods and the presence of organochlorine pesticides in human milk. A total of 167 samples of breastmilk were collected. Sample analysis was carried out by gas chromatography with electron capture detector. Pesticide concentrations (op’DDT, pp’DDT, pp’DDE, Σ-DDT, HCB, β-HCH) were grouped by consumption level of fish, dairy products, meat, eggs, and seafood and then were compared to each other. The odds ratio (OR) was calculated between the concentration of pesticides (higher and/or lower than median) and the exposure variable (high consumption). The results indicated low median concentrations of HCB, β???HCH, op’DDT and pp’DDT, whose fluctuations and trends between different frequencies of food consumption were not significant. pp’DDE and Σ???DDT values according to the increase in consumption of fish were significantly increased. Women with high fish consumption have a higher risk of high concentrations of pp’DDE and Σ-DDT (OR: high consumption: 5.6 (1.3–23.6). A protective effect was observed in the consumption of dairy products (β-HCH and op’DDT), meat (HCB), and seafood (pp’DDT). These results suggest that it is possible that the consumption of fish, dairy products, meat, and seafood influences the presence of organochlorine pesticides in the studied population.     

Phytoremediation of petroleum hydrocarbons in tropical coastal soils I. selection of promising woody plants

GOAL, SCOPE AND BACKGROUND: This glasshouse study is aimed at evaluating tropical plants for phytoremediation of petroleum hydrocarbon-contaminated saline sandy subsurface soils. Tropical plants were selected for their ability to tolerate high salinity and remove No. 2 diesel fuel in coastal topsoil prior to further investigation of the phytoremediation feasibility in deep contaminated soils. The residual petroleum-hydrocarbon contaminant at the John Rogers Tank Farm site, a former petroleum storage facility, at Hickam Air Force Base, Honolulu, Hawaii, is located in a coastal area. It lies below a layer of silt in the subsurface, in loamy sand characterized by moderate salinity and high pH. Little is known regarding the ability of tropical plants to remediate petroleum hydrocarbon-contaminated subsurface soil in Hawaiian and other Pacific Island ecosystems although suitable plants have been identified and utilized for bioremediation in surface soil or marine sediments. METHODS: The experiments were conducted in long narrow pots under glasshouse conditions in two phases. A preliminary experiment was done with nine tropical plants: kiawe (Prosopis pallida), milo (Thespesia populnea), common ironwood (Casuarina equisetifolia), kou (Cordia subcordata), tropical coral tree (Erythrina variegata), false sandalwood (Myoporum sandwicense), beach naupaka (Scaevola sericea), oleander (Nerium oleander), and buffelgrass (Cenchrus ciliaris). These plants were screened for resistance to high salinity treatment (2% NaCl) and two diesel fuel levels (5 and 10 g No. 2 diesel fuel/kg soil) in separate treatments. Plants that showed good tolerance of both factors were further evaluated in a second phase for their efficacy in the phytoremediation of diesel-fuel petroleum hydrocarbons under moderate salinity treatment (1% NaCl). RESULTS: Tropical coral tree and buffelgrass were susceptible to either 2% NaCl or diesel fuel at 10 g/kg soil, but tolerant of diesel fuel at 5 g/kg soil. Kiawe, milo, kou, common ironwood, N. oleander, beach naupaka and false sandalwood were tolerant of high salinity (2% NaCl) or high diesel fuel level (10 g/kg soil). These seven plants were also tolerant of the combined adverse effects of a moderate salinity (1% NaCl) and 10 g diesel fuel/kg soil. Three trees, kiawe, milo and kou significantly accelerated the degradation of petroleum hydrocarbons in the soil spiked with 10 g diesel fuel/kg soil under a moderate salinity treatment (1% NaCl). CONCLUSION: Thus the tropical woody plants, kiawe, milo and kou showed potential for use in phytoremediation of petroleum hydrocarbons in coastal tropical soils. RECOMMENDATIONS AND OUTLOOK: Two fast growing trees, milo and kou, appeared promising for further phytoremediation evaluation in experiments that simulate the soil profile at the field site.     

土壤中铅的植物可利用性化学调控研究

针对重庆市蔬菜重金属污染现状，选取Pb为研究对象，通过盆栽试验，探讨石灰、腐殖酸、硫化钠对污染土壤中Pb活性的影响及Pb在植物体内的积累效应。研究结果表明，石灰、腐殖酸、硫化钠均能降低Pb的植物可利用性。不同石灰用量均能明显抑制Pb向植物迁移；在石灰的各种加入量中，10．0g／kg的加入量对Pb的抑制效果最明显，莴笋中Pb质量分数下降了35．7％；在腐殖酸的各种加入量中，2．67g/kg的加入量对Pb的抑制效果最明显，植物中Pb质量分数下降了23．0％；在硫化钠的各种加入量中，0．47g/kg的加入量对Pb的抑制效果最明显，植物体内Pb质量分数降低了23．8％。各种添加剂均能使植物根部Pb的分配系数下降，而茎、叶Pb的分配系数上升。     

Urban geochemistry: A study of element distributions in the soils of tallinn (Estonia)

First results are presented from the Urban geochemistry of Tallinn, a project supported by the Scientific and Environmental Affairs Division of NATO. The distribution of chemical elements in 532 samples of the topsoils from the territory of the biggest industrial centre of Estonia (pop. 500,000) is interpreted. Statistical analysis and mapping of major and trace elements at the territory of the Tallinn region and of the city were performed and background values and local anomalies of chemical elements on the territory were determined. The investigation focussed on the determination of zones with anomalously high concentrations of elements and the relationships of soil contamination with different pollution sources. The increase of the element concentrations has natural as well as anthropogenic origins. A detailed comparative analysis of the element distributions and the results of a factor analysis showed that the distribution of the major chemical elements depended mainly on the composition of the underlying sedimentary rocks.The territory of Tallinn is characterised by relatively high and widespread concentrations of Ba, Cr, Ga, Ni, Ti and Zn. Especially intensive local concentrations were determined for As, Cr, Mn, Ni, Pb, S, V and Zn, which are typical for the local pollution of the soils by industrial sources. The levels of As, Cr, Mn and V are more than three times. Pb and Zn are more than five times higher in the geochemical anomalies than for background levels. For the Tallinn region two major associations of elements connected with industrial pollutions of the soil are typical: the first association includes Ba, Cr, Mn, Ni and partly Fe and the second one includes As, Pb and Zn. For the city of Tallinn an increase of Ag, Ba, Be, La, Pb, Sn and Zn concentration in the soil was detected. Ba, Cr, Mn and Ni occur in high concentrations in the soils around Maardu. Different types of contamination sources can be identified in Tallinn and its suburbs.     

The Presence of Calcium Oxalate Dihydrate (Weddellite) in Street Sediments from Niterói, Brazil and Its Health Implications

Established research in first world urban environments has shown street sediments to be effective sinks for heavy metals and emphasises the health risks to children by its inhalation or ingestion. In third world countries with fewer pollution controls, contamination may be augmented by additional pollutants such as sewage discharge into urban streets and/or periodic inundation with sewage-laden run-off. This pollutant not only contains heavy metals and organic matter, but calcium oxalates that may derive directly from the sewage itself. To study this premise street sediments were collected from sites of varying industrialisation and sewage contamination within the city of Niteroi, Brazil. Calcium oxalate dihydrate (weddellite) was identified by X-ray diffraction, fourier transform infra red and scanning electron microscopy techniques and oxalate concentrations in <63m and colloidal (clay and organic matter) fractions, were determined by ion chromatography. Oxalate in colloidal fractions averaged 43601mgkg^–1 in sewage contaminated industrialised urban zones, 4519mgkg^–1 in suburban areas and 17477mgkg^–1 in suburbs with favelas (shantytowns-of Niterói). Oxalate concentrations coincide with high levels of metal ions (Fe, Mn, Zn, Pb, Ni, Cr) that stabilise calcium oxalate dihydrate and prevent its dehydration to the monohydrate (whewellite). Lower levels of oxalate were found in lichen-covered roof sediment, plaster and mortar samples. Oxalate concentration coincides with sewage contamination and street sediments appear to act as a sink for calcium oxalate dihydrate derived from sewage. Previous studies have shown that low levels of exposure can damage kidneys and the nervous system, while prolonged exposure can cause severe corneal, retinal and skin damage, cyanosis and possibly gangrene. Contact with blood serum may result in hypocalcemia, muscular stimulation, convulsions and finally collapse. The conditions described are common throughout urban areas of the developing world and may suggest a particular environmental hazard in these regions.