Effect of teeth amalgam on mercury levels in the colostrums human milk in Lenjan

Human milk is usually the only source of food for infants during the first 4 to 5 months of their life. Maternal environmental mercury exposure is directly related to fish consumption or amalgam filling. In this research, 38 human milk samples were collected from mothers of Lenjan area who were not occupationally exposed with mercury. Mercury concentration in human milk was determined by AMA254 Mercury Analyzer. A level of mercury was examined in relation to somatometric, demographic and dental amalgam parameters. Obtained results showed that only dental amalgam significantly increased the mercury level in human milk (p < 0.001). The mean mercury concentrations in milk of mothers without teeth fillings (n = 13), with one to three teeth fillings (n = 10), and four to eight teeth fillings (n = 15) were 2.87, 5.47, and 13.33 μg/l, respectively. The result of this study also showed a positive correlation of mercury milk levels with the number of teeth fillings of the mother (p < 0.05, r = 0.755). The estimated weekly intake of mercury of a breastfed infant in this study was, in some cases, higher than provisional tolerance weekly intake recommended by FAO/WHO, which pose a threat to their health.     

Residue levels of hexachlorocyclohexane and dichlorodiphenyltrichloroethane in human milk collected from Beijing

Forty-eight human breast milk samples were collected from mothers in Beijing. The hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT) (including α-HCH, β-HCH, γ-HCH, δ-HCH, p,p′-DDE, p,p′-DDD, o,p′-DDT, and p,p′-DDT) contents of the samples were determined by gas chromatography/electron capture detection and gas chromatography/mass spectrometry. α-HCH, β-HCH, γ-HCH, p,p′-DDE, p,p′-DDD, and p,p′-DDT were detected at rates of 20, 100, 10, 100, 10, and 22 %, respectively. The average residue levels in the samples were 174.6 ng/g fat for β-HCH, 333.8 ng/g fat for p,p′-DDE, 6.57 ng/g fat for α-HCH, 7.67 ng/g fat for γ-HCH, 4.18 ng/g fat for p,p′-DDD, and 11.4 ng/g fat for p,p′-DDT. The results showed that the infants’ daily intake levels of HCH and DDT were 0.95 and 1.76 μg/kg body weight/day, respectively. Our result suggested that the total residue level of these organochlorine pesticides in breast milk from Beijing decreased and was lower than that from other coastal and heavy industrial cities in China. On the other hand, the levels of HCH and DDT were higher than those from some developed countries, but lower than those from other developing countries such as India.     

Enantiomer ratios,patterns and levels of toxaphene congeners in human milk from Germany

High resolution gas chromatography (HRGC) coupled to quadrupole negative ion chemical ionization (NICI) mass spectrometry (MS) was used to investigate congener patterns, levels and enantiomer distribution of selected toxaphene congeners (#26, #41, #44, #50, #63, B7-1453) in human milk from Germany. #50 and #26 were the most abundant congeners. Furthermore, the identification of B7-1453, B8-1412, #41, #42, #44 and #63 was possible. Levels for the sum of #26, #41, #44 and #50 ranged from 7 to 24 microg kg(-1) milk fat and contributed between 2 and 9% to the total burden of investigated organochlorines such as selected compounds of the chlordane group, HCH, DDT and polychlorinated biphenyls (PCB). Capillaries coated with heptakis-(2,3,6-O-tert-butyldimethylsilyl)-beta-cyclodextrin (TBDMS-CD) or octakis-(2,3,6-tri-O-ethyl)-gamma-cyclodextrin (TEG-CD) were used for the enantioselective separations. Enantiomer ratios (ER) and enantiomer fractions (EF) of the abundant toxaphene congeners #26 and #50 as well as of B7-1453, #41 and #63 were determined. Greatest deviations from a racemic composition in individual human milk samples were found for #41 (1.54-2.37), #50 (1.37-1.72) and #63 (0.53-0.71) whereas ERs for #26 were close to 1. Compared to wildlife biota such as fish and raptors ER changes were more pronounced in human milk but comparable to human adipose tissue.     

Effects of treated sewage sludge levels on temporal variations of some soil properties of a Typic Xerofluvent soil in Menemen Plain, Western Anatolia, Turkey

The aim of this study is to determine effects of treated sewage sludge (TSS) levels as an organic matter (OM) resource on temporal variations of some soil properties of a Typic Xerofluvent soil. The experiment was conducted in Menemen Plain, in the Western Anatolia Region of Turkey (latitudes 38 degrees 34'48.22'-38 degrees 34'49.24' N; longitudes 27 degrees 1'23.05-27 degrees 1'24.14' E) in the years of 2003 and 2004. Moist TSS was added to the soil at the rates of 0, 30, 60 and 90 t ha(-1) on May 1, 2003. Peanut (Arachis hypogaea) was planted as first crop. On the other hand, mixture of green barley (Hordeum vulgare) and common vetch (Vicia sativa L.) was planted as second crop. During the experiment, soil samples were taken in five different periods (1st, June 18, 2003; 2nd, November 13, 2003; 3rd, April 30, 2004; 4th, October 10, 2004 and 5th, May 12, 2004). The results showed that increasing TSS application to Typic Xerofluvent soil was significantly increased total salt, OM, total porosity, micro porosity, macro porosity, field capacity, wilting point, available water content, structure stability index and aggregation percentage values of soil when compared with control. Meanwhile, particle density, dry bulk density and nonaggregated silt + clay values of soil decreased. On the other hand, soil reaction (pH), lime content and total silt + clay values of soil did not significantly change. In the course of time, depending on decomposing of TSS organic materials in soil, effect of TSS levels on soil properties decreased particularly in the last periods. For this reason, it can be recommended that 90 t ha(-1) moist TSS can be added once in 2 years for improving soil properties of Typic Xerofluvent soil, which are characterized by low OM content.     

Mercury contamination in human hair and some marine species from Sfax coasts of Tunisia: levels and risk assessment

The aim of this study was to measure the mercury (Hg) contents of three marine fish and common seafood species (Diplodus annularis, Sarpa salpa and Sepia officinalis) at two sampling sites in the gulf of Gabes, i.e. Sidi Mansour (polluted site) and Kerkennah (control site). These species are frequently consumed by the population living at the Sfax coasts of Tunisia, particularly by the families of fisherman. Additionally, the hair mercury levels of 55 volunteers (28 women, 27 men) were analysed and the daily total mercury intake through the fish and seafood diet was estimated. The key findings were: (1) the mercury contents of the examined fish and seafood species frequently exceeded the regulatory guideline value of 0.5 mg/kg, (2) no site-specific differences in hair mercury contents were found, (3) fish and seafood consumption is probably the major contributor of mercury exposure in this population, (4) the daily mercury intake through frequent consumption of D. annularis exceeds the US EPA reference dose. Further studies are necessary to evaluate the health risks associated with such high mercury exposure levels in order to allow optimal counseling and therapy of the concerned population and to avoid future impairment of human health, particularly children's health.     

Assessment of visual landscape quality using IKONOS imagery

The assessment of visual landscape quality is of importance to the management of urban woodlands. Satellite remote sensing may be used for this purpose as a substitute for traditional survey techniques that are both labour-intensive and time-consuming. This study examines the association between the quality of the perceived visual landscape in urban woodlands and texture measures extracted from IKONOS satellite data, which features 4-m spatial resolution and four spectral bands. The study was conducted in the woodlands of Istanbul (the most important element of urban mosaic) lying along both shores of the Bosporus Strait. The visual quality assessment applied in this study is based on the perceptual approach and was performed via a survey of expressed preferences. For this purpose, representative photographs of real scenery were used to elicit observers’ preferences. A slide show comprising 33 images was presented to a group of 153 volunteers (all undergraduate students), and they were asked to rate the visual quality of each on a 10-point scale (1 for very low visual quality, 10 for very high). Average visual quality scores were calculated for landscape. Texture measures were acquired using the two methods: pixel-based and object-based. Pixel-based texture measures were extracted from the first principle component (PC1) image. Object-based texture measures were extracted by using the original four bands. The association between image texture measures and perceived visual landscape quality was tested via Pearson’s correlation coefficient. The analysis found a strong linear association between image texture measures and visual quality. The highest correlation coefficient was calculated between standard deviation of gray levels (SDGL) (one of the pixel-based texture measures) and visual quality (r?=?0.82, P?<?0.05). The results showed that perceived visual quality of urban woodland landscapes can be estimated by using texture measures extracted from satellite data in combination with appropriate modelling techniques.     

Determination of waterscape beauties through visual quality assessment method

Besides being an indispensable life element, water is also in the first rows among the most important landscape elements that have the visual reserve value in both natural and cultural environments. In this study, the aim was to present suggestions about the use of waterscapes in landscape design and planning attempts by determining the water types bearing high visual reserve values among different types of waterscapes bearing high visual reserve values. The visual quality assessment method was used in this study. One hundred and twenty eight university students ranked the six waterscapes in a visual quality survey. The results showed that urban waterscape scenery [visual quality point (VQP) = 6.0391], was the most preferred category, whereas, river scenery (VQP = 3.5547) was the least preferred. The second preferred waterscape was waterfall (in rural landscape) scenery (VQP = 5.8594) and the third was standing water scenery (SWS; VQP = 5.3672). The relationships between landscape parameters and visual quality of landscape indicated that vividness and fascinaty parameters had a significant relation with preference. Some suggestions were made regarding the use of wa terscapes visual value in planning and designing of the landscape.     

Investigations on boron levels in drinking water sources in China

To evaluate boron contamination of public drinking water in China, both dissolved and total boron contents in 98 public drinking water sources from 49 cities, 42 brands of bottled water samples from supermarkets in several cities, and 58 water samples from boron industrial area were measured by inductively coupled plasma-mass spectrometry (ICP-MS). Our experimental results showed that boron existed in public drinking water sources mainly in dissolved status with total concentrations ranging from 0.003 to 0.337 mg/L (mean = 0.046 mg/L). The mean boron concentrations in mineral and pure bottled water were 0.052 and 0.028 mg/L, respectively. The results obtained in this work showed that there was no health risk on view of boron in public drinking water sources and bottled water. In boron industrial area, boron concentrations in surface water and ground water were 1.28 mg/L (range = 0.007–3.8 mg/L) and 18.3 mg/L (range = 0.015–140 mg/L), respectively, which indicated that boron industry caused boron pollution in local water system.     

Radium equivalent activity in the light of UNSCEAR report

Radium equivalent activity (Ra ( eq )) has been in practice for the last 40 years for the assessment of radiological hazard of radioactivity in environmental materials. The in-practice model for the calculation of the Ra ( eq ) has been critically reviewed in the light of the UNSCEAR 2000 report. Annual effective dose (E) values of (232)Th and (40)K were found to be not equal to that of (226)Ra derived from the activity concentrations of these radionuclides used in the expression for the Ra ( eq ). Therefore, a modified model has been proposed for the determination of the Ra ( eq ) for outdoor external exposure to gamma rays. The relation between the E and Ra ( eq ) has been explored. It is recommended that while describing the radiological hazard of the materials containing radioactivity, there should be no need to calculate the Ra ( eq ) if the E has already been determined or vice versa.     

Effect of light on DIMBOA synthesis in maize leaves as revealed by modified cost-effective extraction method

2,4-Dihydroxy-7-methoxy-1,4-benzoxazine-3-one (DIMBOA) known for its antibiotic properties against many pests and diseases in maize plant was extracted from different varieties. In one of the extraction methods of DIMBOA from maize leaves, Amberlite XAD7, an adsorbent, was used for extracting this and it gave a pure fraction containing DIMBOA. The adsorbent Amberlite XAD, being an expensive material, was uneconomical for processing a large number of samples. Therefore, one of the reported solvent extraction method was modified to make the extraction procedure cost effective without losing the target compounds. Using the modified method, DIMBOA was extracted for different varieties under dark and light condition. Results showed that high concentrations of DIMBOA were extracted from plants grown in dark condition as compared to plants grown in light indicating that light played significant role in inhibition of DIMBOA.     

A comprehensive review of visual air quality at the Grand Canyon

The Grand Canyon, located in Northern Arizona, is one of the seven natural wonders of the world, and has been set aside as a National Park to preserve its unique character. Several million visitors from all over the world travel to the Grand Canyon each year to witness its awesome beauty, As a natural preserve, the area protects numerous values such as genetic diversity, solitude, non-mechanized recreation, etc, but the majority of visitors travel to the Grand Canyon for one reason: to view the scenery.There have been reports in the general press (and even in the United States Congressional Hearings) that visual conditions at the Grand Canyon have been seriously degraded by air pollution. Over the past nine years, a vast array of visibility-related research and monitoring has been conducted to determine the extent and probable cause of this visible degradation. Studies have included optical measurements, pollution characterization, source-receptor relationship analysis, and human perception of visual air quality. The resulting data document the visual air quality of the Grand Canyon and provide a basis to qualitatively and quantitatively evaluate significant events and trends.     

Effects of Forest Management Practices on Mid-Atlantic Streams

Agricultural and urban land use activities have affected stream ecosystems throughout the mid-Atlantic region. However, over 60% of the mid-Atlantic region is forested. A study was conducted to investigate the effects of management practices on forested stream ecosystems throughout the mid-Atlantic region. The study consisted of two phases: Phase 1 was a literature synthesis of information available on the effects of forest management practices on stream hydrology, erosion and sedimentation, riparian habitat alteration, chemical addition, and change in biotic diversity in the mid-Atlantic region. In Phase 2, data from mid-Atlantic streams were analyzed to assess the effects of forest land use on stream quality at the regional scale. Typically, it is the larger order streams in which monitoring and assessment occurs—3^rd order or higher streams. The impacts of forest management practices, particularly hydrologic modifications and riparian buffer zone alteration, occur predominantly in first and second order streams with cumulative impacts translating to higher order streams. Based on the literature review and mid-Atlantic Highland streams analysis, there are short-term (e.g., 2 to 5 years) effects of forest management practices on stream quality at local scales. However, signatures of cumulative effects from forest management practices are not apparent at regional scales in the Highlands. In general, forested land use is associated with good stream quality in the region compared with other land use practices.     

Impact of automobile emissions on the levels of platinum and lead in Accra,Ghana

Examination of car fleet records in Accra demonstrates an increasing proportion of catalytic converter-equipped cars in the relatively old car fleet (average age 13 years) due to their import from developed countries. However, only leaded petrol is sold in Ghana. Lead anti-knocking additives, which are known to affect catalyst activity and promote thermal sintering and mechanical abrasion, may increase Pt emissions. This possible synergism prompted the concomitant determination of Pb and Pt levels in road dust and roadside soils in Ghana. Both metals followed traffic density with higher concentrations in urban areas compared to remote sites. In urban areas, the range for Pb (365 +/- 93 microg g(-1) for dust and 291 +/- 76 microg g(-1) for soil) reflects precatalyst levels in Europe and the US, while the range for Pt (39 +/- 24 ng g(-1) for dust and 15 +/- 5.3 ng g(-1) for soil) is typical for the same countries. The elevated Pt concentrations were unexpected due to recent introduction of catalysts to Ghana compared to the prolonged use of catalysts in Europe and the US.     

Effects of additives on solidification of API separator sludge

API separator sludge was solidified with various combinations of binders and absorbent soil additives. The binders utilized were Type I Portland Cement, Type C Flyash, and a 1:1 combination of the two. The soil additives used were bentonite, diatomite, Fuller's earth, and two brands of chemically altered bentonites, or organoclays. The effectiveness of the solidification materials was based on their effect on the physical and leaching characteristics of the sludge.It was determined the Portland cement and combination binders provided the sludge with adequate physical and strength characteristics. It was also determined the affinity of each additive for water had an important influence on the physical characteristics of the solidified sludge. The results of the leaching procedure indicated the binders alone reduced the leachability of organic constituents from the sludge by 1/5 to 1/10. It appeared the use of the additives with the binders may have further reduced the leachability of constituents from sludge, with the incorporation of the organoclay additives further reducing leachability by up to 1/2. Also, it appeared the absorbing capacity of the additives was directly related to their ability to reduce the leachability of organic constituents from the sludge.     

Effects of seasonal perturbations on a model plankton community

The dynamic behaviour of a model plankton community is described by solutions of a generalized predator‐prey model. The qualitative changes due to variations of parameters are considered and the existence of multistability and catastrophic behaviour is noted. Local and global bifurcations of the system are displayed. A seasonal variation of a parameter is introduced and the resulting dynamics are considered, such as quasiperiodic solutions or chaotic attractors.     

农贸市场噪声对其周围环境的影响

对某农贸市场的场内噪声,场界噪声及其周围居民区环境噪声进行了监测,结果表明,农贸市场营业时,噪声监测值内,场界及居民区均超标;农贸市场不营业时,场界除３个测点略超标外,余达标,居民区略超标。就农贸市场噪声对其周围环境的影响,提出了控制对策。