Introduction: Single sample TWA samples collected over an 8-hour shift have the potential to mask elevated exposures, excursions or “peaks” that may have occurred thus permitting situations where workers are over-exposed or indeed over-dosed. The objectives of this study, undertaken in a small acrylic sheet manufacturing plant, are therefore to identify tasks that have the potential to exceed short-term occupational exposure levels and then simultaneously monitor employees undertaking these tasks for 8-hour TWA and Short-Term exposure concentrations. The results obtained from this sampling are then compared to their respective legal limits and then finally correlated to establish their statistical significance. Materials and Methods: The study setting comprises a syrup room wherein two employees are assigned per shift. Employees in this setting manufacture an acrylic “syrup” which is achieved by dosing raw materials into any one of 13 mixing vessels. Whilst mixing, these vessels also heat the ingredients until the required viscosity is reached. This “syrup” comprising mostly of liquid methyl methacrylate, is then decanted into a pressure vessel from where it is pipe-fed into a casting chamber and finally poured between two glass sheets. When cured, the final product is stored and sold as a clear or tinted acrylic sheet. All operations with this area are therefore associated with facilitating the syrup manufacture. Personal 8-hour TWA and Task- Based measurements of methyl methacrylate vapour were simultaneously obtained from the breathing zones of six employees over five separate shifts. These employees routinely work within the setting and also undertake tasks that have the potential to exceed the Short-Term Occupational Exposure Limit (ST-OEL) for methyl methacrylate vapour. Tasks were studied and those selected for quantitative monitoring were captured using a qualitative risk assessment tool. These selections were based on studying each task to establish the employee’s exposure probability and severity i.e. whether performing the task could indeed lead to excessive Short-Term exposures. Eight-hour TWA monitoring was undertaken using activated carbon 3M 3500 passive monitoring badges which were attached to each of the subject’s breathing zone and left over 80 % of the shift. The task-based measurements were obtained by using a Drager PAC III electro-chemical monitoring instrument, which was also placed in each each 4 subject’s breathing zone, and provided real-time exposure data whilst the employees were undertaking the various tasks. Results: All measurements (N = 116) were obtained over a series of 5 full-shift monitoring periods. When analysed, 8 of the 10 of the TWA samples returned results that were below the 8-hour TWA OEL. Of the 106 task-based measurements obtained for the nine identified tasks, when averaged, 89.1 % of results exceeded the ST-OEL. When the TWA and ST measurements were correlated, only one of the nine tasks were statistically significant in their correlation. This correlation coefficient was however highly statistically significant (r = 0.339, p = 0.032 and r = 0.337, p = 0.022 respectively). Both negative and positive correlations were obtained however these were statistically insignificant. Discussion: A significantly higher proportion of the sample results were above the STOEL than the 8-hour TWA OEL concentrations contributing to the argument that ST exposure monitoring may add additional insight to employees’ exposure profiles. A major limitation of the study is however the small sample size, which makes it difficult, due to inter-worker variability amongst other factors, to extrapolate the results and their corresponding interpretations to larger, more generalised occupational hygiene monitoring scenarios. Conclusion: The results obtained therefore support the assertion that the inclusion of short-term monitoring is important in characterising employee exposures in situations where these tasks are themselves potential sources of significant chemical exposures. Recommendations: As a basis for undertaking any form of monitoring and particularly in settings where short-term, task-based exposures may exist, the importance of undertaking a systematic approach to hazard identification and risk profiling via the use of a known risk assessment tool to compile a air sampling programme, has been demonstrated in the results of this research. Further research that specifically addresses the problem of characterising workplace exposures would be useful in larger study populations as well as occupational settings which expose employees to the various types of airborne contaminant e.g. fume, mists, particulates and gases.

A three-part project was devised to investigate the origins of and potential methods to reduce the risk of occupational exposure to cytotoxic drugs. The first phase involved researching the current decontamination methods applied in UK hospital pharmacies, which manipulate cytotoxic drugs. The second phase evaluated practical decontamination methods, and the third phase investigated one intervention aimed at reducing or preventing contamination occurring in an isolator. A questionnaire was sent out to ASU managers in NHS hospital pharmacies to gain information about the disinfection and decontamination procedures and products used. The practical decontamination methods investigated were mechanical removal and degradation by detergents (pH range from 1.7 - 13.2) and cleaning agents, and degradation by vaporised hydrogen peroxide. Analytical methods were developed and validated to recover and quantify the amount of cytotoxic marker drug remaining after the decontamination tests carried out in phase two, and to recover and quantify cytotoxic surface contamination from various surfaces in phase three of this work. This composed an attempt to evaluate the effectiveness of a closed-system e.g. PhaSeal® device for fluid-transfer, in reducing contamination produced from the compounding of cytotoxic drugs in an isolator. The detergents and cleaning agents were effective in removing or reducing cytotoxic surface contamination. Alkaline detergents caused degradation of doxorubicin (maximum 81% at pH 13.2 after 1 hour exposure); the other detergents tested did not xi x degrade the cytotoxic drugs investigated. Exposure to vaporised hydrogen peroxide (1.6g min-1 for 2 hours) caused the degradation of cyclophosphamide (98.9%), 5-Fluorouracil (29.3%), doxorubicin (71.0%) and epirubicin (65.9%) when exposed in pharmaceutical diluents. The closed-system (PhaSeal®) device was effective in reducing contamination produced in an isolator from the compounding of cytotoxic drugs. The risk posed by handling and manipulation of cytotoxic drugs and products to the operator and the environment may be reduced, if not eliminated by considering additional approaches to the methods already in place. Firstly, the application of effective decontamination methods; and secondly, by using an effective closed-system, for example the PhaSeal® drug transfer device in a controlled environment.

The overall goal of the present research project was to investigate the physiology of dietary iron absorption and its interactions with the uptake and metabolism of other divalent metals, especially cadmium, in freshwater fish, using rainbow trout (Oncorhynchus mykiss) as a model species. Using intestinal sac preparations, iron absorption was found to occur along the entire intestinal tract of fish, with anterior intestine being the major site of absorption compared to either mid or posterior intestine. Ferrous iron was more bioavailable than ferric iron, and the uptake of ferrous iron was significantly reduced at alkaline pH (p < 0.05). These findings suggested that a homolog of the mammalian apical ferrous iron transporter, divalent metal transporter-1 (DMT1, a Fe2+/H+ symporter), is involved in the absorption of iron in the fish intestine. Ferric iron appeared to be absorbed through the same pathway as ferrous iron following reduction by an apical ferric reductase. Several divalent metals, both essential (nickel, copper and zinc) and non-essential (cadmium and lead), inhibited intestinal ferrous iron absorption in fish. Importantly, elevated luminal iron reciprocally reduced the accumulation of cadmium in the fish intestine, indicating the significance of the iron transport pathway in dietary cadmium absorption. Two different DMT1 isoforms, Nramp-â and -ã, were found to be expressed along the entire gastrointestinal tract of fish. My study showed that in isolated rainbow trout enterocytes, ferrous iron uptake occurred through a saturable and proton-dependent process, providing further evidence of DMT1-mediated ferrous iron transport. Both cadmium and lead inhibited ferrous iron uptake in the enterocytes in a concentration-dependent manner. Kinetic characterization revealed that the apparent affinity for ferrous iron uptake is significantly decreased (increased Km) in the presence of either cadmium or lead (p < 0.05), whereas the maximum uptake rate (Jmax) remains unchanged. These results indicated that the interaction between ferrous iron and cadmium or lead is competitive in nature, and the uptake of these metals occurs through a common transport pathway (likely DMT1). The uptake characteristics of cadmium were further examined in isolated rainbow trout enterocytes, and my findings indicated that in addition to DMT1, cadmium uptake can be mediated by zinc transport pathway (ZIP8, a Zn2+/HCO3- symporter). My study also showed that cysteine-conjugated cadmium was readily bioavailable to fish enterocytes, possibly via a cysteine-specific transport pathway. The efflux of cadmium from the enterocytes was found to occur via an ATPase-driven pathway. On the other hand, chronic exposure to dietary cadmium at an environmentally-relevant concentration significantly increased cadmium burden in target organs as well as in the whole-body of fish (p < 0.05). Exposure to dietary cadmium increased the mRNA expression level of key stress-inducible proteins such as metallothioneins (MT-A and MT-B) and heat shock proteins-70 (HSP-70a and HSP-70b). Interestingly, each MT and HSP-70 mRNA isoform responded differently in various target organs of fish following dietary cadmium exposure. Fish exposed to dietary cadmium also exhibited an increase in the hepatic transferrin mRNA level as well as the plasma transferrin protein level, indicating the role of transferrin in cadmium handling in fish. Importantly, an iron-supplemented diet reduced cadmium burden in the gut and the whole-body, and ameliorated the expression of MT and HSP-70 genes in fish. These results suggested the protective effects of elevated dietary iron against chronic dietary cadmium toxicity in fish. Overall, findings from the present research project provided novel and important physiological and molecular insights into the uptake, interactions and homeostasis of dietary divalent metals in freshwater fish. This information greatly enhances our current understanding of the toxicological implications for dietary metal exposure in metal contaminated wild fish populations, and may ultimately help the regulators to develop better strategies for ecological risk assessment of metals.

The overall goal of the present research project was to investigate the physiology of dietary iron absorption and its interactions with the uptake and metabolism of other divalent metals, especially cadmium, in freshwater fish, using rainbow trout (Oncorhynchus mykiss) as a model species. Using intestinal sac preparations, iron absorption was found to occur along the entire intestinal tract of fish, with anterior intestine being the major site of absorption compared to either mid or posterior intestine. Ferrous iron was more bioavailable than ferric iron, and the uptake of ferrous iron was significantly reduced at alkaline pH (p < 0.05). These findings suggested that a homolog of the mammalian apical ferrous iron transporter, divalent metal transporter-1 (DMT1, a Fe2+/H+ symporter), is involved in the absorption of iron in the fish intestine. Ferric iron appeared to be absorbed through the same pathway as ferrous iron following reduction by an apical ferric reductase. Several divalent metals, both essential (nickel, copper and zinc) and non-essential (cadmium and lead), inhibited intestinal ferrous iron absorption in fish. Importantly, elevated luminal iron reciprocally reduced the accumulation of cadmium in the fish intestine, indicating the significance of the iron transport pathway in dietary cadmium absorption. Two different DMT1 isoforms, Nramp-â and -ã, were found to be expressed along the entire gastrointestinal tract of fish. My study showed that in isolated rainbow trout enterocytes, ferrous iron uptake occurred through a saturable and proton-dependent process, providing further evidence of DMT1-mediated ferrous iron transport. Both cadmium and lead inhibited ferrous iron uptake in the enterocytes in a concentration-dependent manner. Kinetic characterization revealed that the apparent affinity for ferrous iron uptake is significantly decreased (increased Km) in the presence of either cadmium or lead (p < 0.05), whereas the maximum uptake rate (Jmax) remains unchanged. These results indicated that the interaction between ferrous iron and cadmium or lead is competitive in nature, and the uptake of these metals occurs through a common transport pathway (likely DMT1). The uptake characteristics of cadmium were further examined in isolated rainbow trout enterocytes, and my findings indicated that in addition to DMT1, cadmium uptake can be mediated by zinc transport pathway (ZIP8, a Zn2+/HCO3- symporter). My study also showed that cysteine-conjugated cadmium was readily bioavailable to fish enterocytes, possibly via a cysteine-specific transport pathway. The efflux of cadmium from the enterocytes was found to occur via an ATPase-driven pathway. On the other hand, chronic exposure to dietary cadmium at an environmentally-relevant concentration significantly increased cadmium burden in target organs as well as in the whole-body of fish (p < 0.05). Exposure to dietary cadmium increased the mRNA expression level of key stress-inducible proteins such as metallothioneins (MT-A and MT-B) and heat shock proteins-70 (HSP-70a and HSP-70b). Interestingly, each MT and HSP-70 mRNA isoform responded differently in various target organs of fish following dietary cadmium exposure. Fish exposed to dietary cadmium also exhibited an increase in the hepatic transferrin mRNA level as well as the plasma transferrin protein level, indicating the role of transferrin in cadmium handling in fish. Importantly, an iron-supplemented diet reduced cadmium burden in the gut and the whole-body, and ameliorated the expression of MT and HSP-70 genes in fish. These results suggested the protective effects of elevated dietary iron against chronic dietary cadmium toxicity in fish. Overall, findings from the present research project provided novel and important physiological and molecular insights into the uptake, interactions and homeostasis of dietary divalent metals in freshwater fish. This information greatly enhances our current understanding of the toxicological implications for dietary metal exposure in metal contaminated wild fish populations, and may ultimately help the regulators to develop better strategies for ecological risk assessment of metals.

ABSTRACT With the trend toward global economic and financial integration, liberalization of financial market, increasing of new fashioned financial products and capital mobility, banks may consciously or inadvertently hold large open foreign exchange positions. It in turns may suffer loses due to adverse exchange rate movements. Thus, the bank may even seriously damage to their capital base. Therefore, study in foreign exposure problem has special and important meaning for banks operation and risk management. Although The Basle Committee has compromised the regulation of measuring foreign exchange position ¡V NAP and GAP to BAP, in view of the theory of studying such position measurement, it¡¦s necessary to develop a more generalized concept of weighted aggregate position (WAP) to make it closely to ¡§theoretically correct position¡¨. An empirical test of a typical local foreign exchange bank¡¦s foreign currency position appeared that both BAP and GAP provide a more significant effect for the foreign exchange exposure than NAP. Nevertheless, by considering the cost of hedge, proposing of BAP may be more practical than GAP.

Local exhaust (LE) ventilation is a ventilation technique where contaminated air is locally extracted close to the contaminant source usually with the purpose to reduce the exposure of workers to dust, fumes or vapour, which can be hazardous to their health. The performance of a LE installation depends however on many influential factors, and there is not yet an international standardized way to test LE constructions. The present study is the natural continuation of some previous studies at the University of Gävle that aimed at contributing to the establishment of such tests. The study entails full scale experimental measurements that include 3-D air velocity measurements and tracer gas tests in a controlled air turbulence environment generated through physical movements of a vertical, human-sized cylinder. These measurements were focused on human exposure, which was analysed by means of a seated human simulator for different configurations in which the exhaust flow rate, turbulence level, the exhaust hood arrangement and the measuring/injecting distance varied. The use of a sonic 3-D anemometer, that yielded both magnitude and direction of the air movement, proved very useful in analysing the generated air turbulence. As a measure of the LE performance, PNV value (Percentage of Negative Velocities) was used. This measure represents the percentage of time when the air flow at the measuring point in front of the exhaust hood is directed away from the nozzle, i.e. when the velocity component in the direction towards the exhaust hood opening is negative. Regarding the results obtained, in an otherwise undisturbed environment, measurement data showed that the natural convection from the human simulator sitting in front of the LE introduces some disturbances of the air flow in the suction region, proportional to the exhaust flow rate. However, when additional turbulence was generated through the controlled movements of the human-sized cylinder, thus creating a controlled turbulence setting, natural human convection leaded to a lower percentage of negative velocities (PNV) in comparison with the case in which human simulator was not present, especially for low exhaust air flow rates and when the exhaust hood was raised from the table. The tracer gas tests implied injection of a neutrally buoyant tracer gas through a perforated sphere placed in front of the exhaust hood. The amount of tracer gas that escaped from the suction flow was measured both in the room air and in the breathing zone. The first measurements yielded a sensitive method for measuring the capture efficiency (CE) of the exhaust hood. The CE is the percentage of injected tracer gas that is directly captured by the exhaust hood. This parameter showed that although the  convection flow generated by the human simulator leads to low PNV values, it seems that the tracer gas is not actually being captured, but trapped in that convection flow. As a consequence, PNV and CE get a strong correlation, which is even more intense when injection and capture point are closer together. Hence, PNV represents a good alternative to tracer gas measurements only if the relationship between the correlation of PNV and CE with respect to the distance from the injection to the capture point is known. Finally, measurements of tracer gas in the breathing zone showed random, short and high exposures when turbulence was generated and those exposures got worse by natural human convection.

Available information in Swaziland indicates that there are stocks of persistent organic pesticides that have been discontinued elsewhere because of their carcinogenic, mutagenic and teratogenic properties. Some of these pesticides, such as DDT and endosulfan, are still used in agriculture to protect crops and livestock from pests and diseases, and in vector control especially mosquitoes. There has been an increase in the use of these pesticides over the years. It is estimated that about 30–40% of the population may have already been exposed to these pesticides. The cultural and lifestyle determinants of pesticide exposure are highlighted.

In British Columbia harvested forests are manually replanted by seasonal workers. Fertilizers contained in perforated paper sachets are often planted with seedlings. There have been anecdotal reports of skin and respiratory illness associated with fertilizer exposure and due to potential metal content in fertilizer source material they may contain metals as contaminants. Workers may also be exposed to pesticide residues on seedlings. This study aimed to characterize fertilizer, metal and pesticide exposure among a sample of B.C. tree planters, and to examine worker respiratory and dermal health. Between May 2006 and April 2007 223 tree planters were interviewed about their respiratory and dermal health, and the exposures of 54 tree planters at five geographically-disperse worksites were monitored. Four worksites were using fertilizer and one was not. The health questionnaire was a modification of the American Thoracic Society standardized questionnaire with questions on dermal health taken from a previous UBC study. Workers were grouped in exposure categories and symptoms analysed using logistic regression. Metals were measured by ICP/MS on post shift hand wipes, full shift air sample filters, in whole blood, bulk soil, seedling root balls, and fertilizer samples. Pesticides were measured on post shift hand wipes and on bulk seedling samples. Using nursery pesticide application records, analyses focused on known pesticides applied to the seedlings at the study sites. Carbamate pesticides were analyzed by HPLC/MS and other pesticides by GC/MS. No evidence was found that tree planters who work with fertilizer are at an elevated risk of exposure to arsenic, lead, cadmium, chromium and nickel relative to other tree planters. Pesticide residues were found on seedlings taken from coastal work sites in April 2007. At coastal worksites the fungicides chlorothalonil and iprodione were found on the skin of workers at low levels (range 0.37 – 106.3 ng.cm² and 0.48 – 15.9 ng/cm² respectively). Work with fertilizer was linked with an increased risk of cough, phlegm, nasal symptoms, nose bleed, and skin irritation. Hygiene conditions at tree planting work sites are very poor. Although measured exposures were low, hygiene conditions should improve to reduce the risk of health symptoms among tree planters.

No description available.

No description available.