scholarly journals Spatial distribution of PCDDs, PCDFs and dl-PCBs along the cascade of urban reservoirs

2012 ◽  
Vol 44 (4) ◽  
pp. 614-630 ◽  
Author(s):  
Magdalena Urbaniak ◽  
Marek Zieliński ◽  
Zbigniew Kaczkowski ◽  
Maciej Zalewski
Keyword(s):  
Total Concentration ◽  
Sediment Traps ◽  
Chemical Processes ◽  
World Health ◽  
Urban Water ◽  
River Ecosystem ◽  
River Continuum ◽  
Continuum Concept ◽  
Water Ecosystems ◽  
Health Organization

The river environment is a highly complex system with a variety of processes continuously changing along its continuum (River Continuum Concept). Therefore identification of the threats that result from different elements of the river ecosystem is an intricate task, mainly because of the transportation and biological, geological and chemical processes occurring in such a system. The overall objective of the presented study was to examine the concentration and pattern of polychlorinated dibenzo-para-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in the five urban, cascade reservoirs. The obtained data demonstrated an increasing total concentration of toxic PCDDs/PCDFs and dl-PCBs along the studied reservoirs starting from 266 ng/kg d.w. in the first pond up to 11,400 ng/kg d.w. in the last pond, wherein the highest World Health Organization – Toxic Equivalent (WHO-TEQ) concentration (18.9 ng TEQ/kg d.w.) was also recorded. The exception from this rule, with the lowest total and WHO-TEQ concentrations (182 ng/kg d.w. and 1.31 ng TEQ/kg d.w., respectively) was the middle newly constructed III reservoir, equipped with the sediment traps and sand separators at the stormwater outlets and ecotone zones around its catchment for enhancing the purification of inflowing stormwater. This situation may indicate the importance of such solutions for the reduction of PCDDs, PCDFs and dl-PCBs in the urban water ecosystems.

Questions and Comments on the River Continuum Concept

1985 ◽  
Vol 42 (5) ◽  
pp. 1038-1044 ◽  
Author(s):  
Bernhard Statzner ◽  
Bert Higler
Keyword(s):  
Environmental Variability ◽  
Theoretical Background ◽  
River Continuum Concept ◽  
Key Factors ◽  
River Continuum ◽  
Running Water ◽  
Current State ◽  
Biotic Diversity ◽  
Continuum Concept ◽  
Water Ecosystems

The River Continuum Concept (RCC) is a generalized conceptual framework for characterization of pristine running water ecosystems. Of the numerous tenets of the concept we particularly reevaluated the following: biological analogues of energy equilibrium and entropy in the physical system; maximization of energy consumption through continuous species replacement over a year; absence of succession in stream ecosystems, which can thus be viewed in a time-independent fashion; and maximization of biotic diversity in midreaches of streams as a result of the occurrence of highest environmental variability there together with spatial abundance shifts of insects, molluscs, and crustaceans. When emphasis is placed on rapid changes in the downstream hydraulics dependent on discharge and slope (both of which are expressed by stream order in the RCC and are key factors of the concept) and on results from tropical studies, some of these tenets are partly refuted or need extension. Some of them are in conflict with the current state of knowledge in other domains of stream ecology or are at least open to various interpretations. Therefore, we advocate modifications of the theoretical background of the RCC.

scholarly journals Assessing the Removal of Arsenite and Arsenate Mixtures from the Synthetic Bangladesh Groundwater (SBGW) Using Combined Fe(VI)/Fe(III) Treatments and Local Regression Analysis

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1134
Author(s):  
Javier Quino-Favero ◽  
Raúl Eyzaguirre Perez ◽  
Patricia Prieto Veramendi ◽  
Paloma Mogrovejo García ◽  
Lisveth Flores del Pino
Keyword(s):  
Natural Waters ◽  
Arsenic Removal ◽  
Total Concentration ◽  
World Health ◽  
Local Regression ◽  
Oxidation Reduction ◽  
Combined Use ◽  
Inorganic Pollutant ◽  
Ph Level ◽  
Health Organization

Arsenic is an inorganic pollutant that, depending on oxidation–reduction and pH level conditions, may be found in natural waters in two variants: As(III) and As(V). Any treatment to effectively remove arsenic from water will be conditioned by the presence of one or both variants. In this context, this study assesses using electrochemically produced Fe(VI) with Fe(III) to remove As(III), As(V), and their combinations from the Synthetic Bangladesh Groundwater (SBGW) containing anions that interfere with iron-based arsenic removal processes. The combined use of Fe(VI) and Fe(III) allowed us to remove the total arsenic below the 10 mg L−1 threshold established by the World Health Organization and Peruvian regulations for drinking water. An optimum combination of 1 mg L−1 of Fe(VI) and 30 mg L−1 of Fe(III) was identified and tested on the removal of four different proportions of As(III):As(V) for two total concentrations: 500 and 250 mg L−1. There were no significant differences in the final removal values under the different proportions of As(III):As(V) for each total concentration, with a final removal average of 99.0% and 96.9% for the 500 and 250 µg L−1 concentrations, respectively.

scholarly journals Determination of Selected Heavy Metals in Tobacco Tree Shrubs Growing around Dandora Dumpsite, Nairobi, Kenya

2019 ◽  
pp. 1-9
Author(s):  
P. M. Kahara ◽  
J. Murungi ◽  
J. K. Kiptoo ◽  
G. Nyaga
Keyword(s):  
Heavy Metals ◽  
Total Concentration ◽  
Pearson Correlation ◽  
World Health ◽  
Loading Path ◽  
Flame Atomic Absorption Spectroscopy ◽  
Flame Atomic Absorption ◽  
Top Soil ◽  
Health Organization

Environmental pollution by heavy metals is presently a serious threat to public health. Despite the toxic contaminants contained in municipal waste, most of the dumpsites remain unregulated and uncontrolled. The objective of this study was to determine the levels of Pb, Cr and Cd in the leaves of tobacco tree plants growing around the dumpsite so as to assess their impact on the environment. The pseudo-total concentration of the metals in the soil was done so as to calculate the transfer factors.pH and total organic carbon (TOC) of the soil was also determined. Soil and plant samples were collected thrice from thirty two sampling sites along the off-loading path from the centre of Dandora dumpsite up to a distance of 700 m away from the centre at depth of 0-30cm (top soil).  Metal analysis was done using flame atomic absorption spectroscopy (FAAS). Pb levels ranged from 7.58±0.34 to 16.57±0.79 µg/g in the washed leaves and 9.22±0.36 to 19.27±0.40 µg/g in the unwashed leaves. Cr levels ranged from 5.11±0.40 to 14.4±0.91 µg/g in the washed leaves and 5.01±0.45 to 15.50±0.40 µg/g in the unwashed leaves. While Cd levels ranged from 0.24±0.01 to 3.62 ±0.17 µg/g in the washed leaves and 0.37±0.02 to 3.68±0.25 µg/g in the unwashed leaves. All these levels were above World Health Organization recommended limits in plants of Pb (0.3 µg/g), Cr (3 µg/g) and Cd (0.2 µg/g). Pearson correlation of the levels in the plants with their concentrations in the soils gave significantly positive values. This suggest that high metal concentration in the soil leads to increased mobility and hence bioavailability. Results obtained therefore suggest that Dandora dumpsite is highly polluted and people should be discouraged from using waste from the dumpsite as manure.

scholarly journals Are the existing guidelines sufficient for the assessment of bathing water quality? The example of Polish lakes

2021 ◽  
Author(s):  
Eugeniusz Pronin
Keyword(s):  
Cyanobacterial Blooms ◽  
World Health ◽  
Additional Parameter ◽  
Small Water ◽  
Bathing Water Directive ◽  
Bathing Water ◽  
Bathing Waters ◽  
Water Ecosystems ◽  
Visual Confirmation ◽  
Health Organization

AbstractThe safety of beachgoers and swimmers is determined by the presence or absence of microbial contaminants and cyanobacterial toxins in the water. This study compared the assessment of bathing waters according to the Bathing Water Directive, which is based on the concentration of fecal contaminants, with some modifications, and a new method based on the concentration of chlorophyll-a, which corresponds to the World Health Organization (WHO) guidelines used for determining cyanobacterial density in the water posing threat to people health. The results obtained from the method based on chlorophyll-a concentration clearly showed that the number of bathing waters in Poland with sufficient and insufficient quality were higher in 2018 and 2019, compared to the method based on microbial contamination. The closing of bathing waters based only on the visual confirmation of cyanobacterial blooms might not be enough to prevent the threat to swimmers’ health. The multivariate analyses applied in this study seem to confirm that chlorophyll-a concentration with associated cyanobacterial density might serve as an additional parameter for assessing the quality of bathing waters, and in the case of small water reservoirs, might indirectly inform about the conditions and changes in water ecosystems.

Obstacles to Claiming Permanence and Injury-Relatedness for “Posttraumatic” Headache

2009 ◽  
Vol 14 (3) ◽  
pp. 3-6
Author(s):  
Robert J. Barth
Keyword(s):  
Complete Recovery ◽  
World Health ◽  
Related Factors ◽  
Posttraumatic Headache ◽  
Sixth Edition ◽  
Causative Relationship ◽  
Short Period ◽  
The One ◽  
Health Organization ◽  
Subjective Reports

Abstract “Posttraumatic” headaches claims are controversial because they are subjective reports often provided in the complex of litigation, and the underlying pathogenesis is not defined. This article reviews principles and scientific considerations in the AMAGuides to the Evaluation of Permanent Impairment (AMA Guides) that should be noted by evaluators who examine such cases. Some examples in the AMA Guides, Sixth Edition, may seem to imply that mild head trauma can cause permanent impairment due to headache. The author examines scientific findings that present obstacles to claiming that concussion or mild traumatic brain injury is a cause of permanent headache. The World Health Organization, for example, found a favorable prognosis for posttraumatic headache, and complete recovery over a short period of time was the norm. Other studies have highlighted the lack of a dose-response correlation between trauma and prolonged headache complaints, both in terms of the frequency and the severity of trauma. On the one hand, scientific studies have failed to support the hypothesis of a causative relationship between trauma and permanent or prolonged headaches; on the other hand, non–trauma-related factors are strongly associated with complaints of prolonged headache.

Sixth Edition: the New Standard

2008 ◽  
Vol 13 (1) ◽  
pp. 1-12
Author(s):  
Christopher R. Brigham ◽  
Robert D. Rondinelli ◽  
Elizabeth Genovese ◽  
Craig Uejo ◽  
Marjorie Eskay-Auerbach
Keyword(s):  
Review Process ◽  
Peer Review Process ◽  
World Health ◽  
International Classification Of Functioning ◽  
Revision Process ◽  
Sixth Edition ◽  
Impairment Ratings ◽  
Health Organization ◽  
Impairment Severity

Abstract The AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Sixth Edition, was published in December 2007 and is the result of efforts to enhance the relevance of impairment ratings, improve internal consistency, promote precision, and simplify the rating process. The revision process was designed to address shortcomings and issues in previous editions and featured an open, well-defined, and tiered peer review process. The principles underlying the AMA Guides have not changed, but the sixth edition uses a modified conceptual framework based on the International Classification of Functioning, Disability, and Health (ICF), a comprehensive model of disablement developed by the World Health Organization. The ICF classifies domains that describe body functions and structures, activities, and participation; because an individual's functioning and disability occur in a context, the ICF includes a list of environmental factors to consider. The ICF classification uses five impairment classes that, in the sixth edition, were developed into diagnosis-based grids for each organ system. The grids use commonly accepted consensus-based criteria to classify most diagnoses into five classes of impairment severity (normal to very severe). A figure presents the structure of a typical diagnosis-based grid, which includes ranges of impairment ratings and greater clarity about choosing a discreet numerical value that reflects the impairment.

The Historical Development of Burden of Treatment Compliance

2014 ◽  
Vol 19 (5) ◽  
pp. 13-15
Author(s):  
Stephen L. Demeter
Keyword(s):  
Internal Medicine ◽  
Treatment Compliance ◽  
World Health ◽  
International Classification Of Functioning ◽  
Sixth Edition ◽  
Burden Of Treatment ◽  
Specific Goal ◽  
Surrogate Measure ◽  
Health Organization

Abstract A long-standing criticism of the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides) has been the inequity between the internal medicine ratings and the orthopedic ratings; in the comparison, internal medicine ratings appear inflated. A specific goal of the AMA Guides, Sixth Edition, was to diminish, where possible, those disparities. This led to the use of the International Classification of Functioning, Disability, and Health from the World Health Organization in the AMA Guides, Sixth Edition, including the addition of the burden of treatment compliance (BOTC). The BOTC originally was intended to allow rating internal medicine conditions using the types and numbers of medications as a surrogate measure of the severity of a condition when other, more traditional methods, did not exist or were insufficient. Internal medicine relies on step-wise escalation of treatment, and BOTC usefully provides an estimate of impairment based on the need to be compliant with treatment. Simplistically, the need to take more medications may indicate a greater impairment burden. BOTC is introduced in the first chapter of the AMA Guides, Sixth Edition, which clarifies that “BOTC refers to the impairment that results from adhering to a complex regimen of medications, testing, and/or procedures to achieve an objective, measurable, clinical improvement that would not occur, or potentially could be reversed, in the absence of compliance.

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