Modelling of occupational respirable crystalline silica exposure for quantitative exposure assessment in community-based case-control studies

We describe an empirical model for exposure to respirable crystalline silica (RCS) to create a quantitative job-exposure matrix (JEM) for community-based studies. Personal measurements of exposure to RCS from Europe and Canada were obtained for exposure modelling. A mixed-effects model was elaborated, with region/country and job titles as random effect terms. The fixed effect terms included year of measurement, measurement strategy (representative or worst-case), sampling duration (minutes) and a priori exposure intensity rating for each job from an independently developed JEM (none, low, high). 23,640 personal RCS exposure measurements, covering a time period from 1976 to 2009, were available for modelling. The model indicated an overall downward time trend in RCS exposure levels of -6% per year. Exposure levels were higher in the UK and Canada, and lower in Northern Europe and Germany. Worst-case sampling was associated with higher reported exposure levels and an increase in sampling duration was associated with lower reported exposure levels. Highest predicted RCS exposure levels in the reference year (1998) were for chimney bricklayers (geometric mean 0.11 mg m(-3)), monument carvers and other stone cutters and carvers (0.10 mg m(-3)). The resulting model enables us to predict time-, job-, and region/country-specific exposure levels of RCS. These predictions will be used in the SYNERGY study, an ongoing pooled multinational community-based case-control study on lung cancer.     

Volunteer monitoring of E. coli in streams of the upper Midwestern United States: a comparison of methods

Fecal contamination of water is a public health concern for those using the water for drinking or recreation. The EPA recommends using Escherichia coli to evaluate recreational freshwaters for fecal contamination. With limited resources available, states have recently focused on training volunteers to expand data collection and resource assessment. Several bacteria testing methods are available for use by the public; however, few studies have comprehensively evaluated their use by volunteers. This study evaluated two E. coli monitoring methods used by volunteers: Coliscan Easygel® and 3M^TM Petrifilm^TM, incubated for 24 and 48 hours. The methods were assessed to determine how closely each matched results with EPA-approved laboratory analyses. Analysis of covariance results indicated that when used by volunteers to monitor surface water, 3M^TM Petrifilm^TM results were more similar to laboratory analyses than Coliscan Easygel®. Both test methods had similar overall accuracy of predicting if a sample exceeded or fell below the 235 cfu/100 mL EPA body contact standard for recreational surface waters. Two-thirds of volunteers preferred 3M^TM Petrifilm^TM.     

Dioxins, PCBs, metals, metalloids, pesticides and antimicrobial residues in wild and farmed Australian southern bluefin tuna (Thunnus maccoyii)

Data concerning the concentration of dioxins (PCDD/PCDFs), polychlorinated biphenyls (PCBs), metals, metalloids, pesticides and antimicrobials residues are reported for the edible portion of Australian wild and farmed southern bluefin tuna (Thunnus maccoyii). In 2004 wild caught (n=5) and farmed (n=26) southern bluefin tuna (SBT) were collected. The mean concentration of total mercury on a fresh weight (fw) basis was 0.34 mg/kg in wild SBT and 0.31 mg/kg in farmed SBT. Concentrations of dioxins (PCDD/PCDFs) and polychlorinated biphenyls (PCBs) found in wild SBT were extremely low. The mean concentration (fw) of the sum of PCDD/PCDFs and the dioxin-like PCBs was 0.27 pg TEQ/g in wild SBT and 0.61 pg TEQ/g in farmed SBT. Mean PCB total concentration (fw basis) was 0.47 ng/g in wild SBT and 6.60 ng/g in farmed SBT. No detectable residues of any pesticide or antimicrobial compounds were found. All residues detected were within regulatory limits set by the Japanese Competent Authority, the Ministry of Health, Labour and Welfare (MHLW) and the Australian Competent Authority, Food Standards Australia New Zealand (FSANZ). The need for harmonisation of international product integrity procedures for bluefin tunas in international trade is highlighted.     

Bacterial cell monitoring in wastewater treatment plants by flow cytometry.

The activated sludge process is performed by a variable and mixed community of microorganisms in an aerobic aquatic environment, in which bacteria constitute the majority and represent the main microorganisms responsible for the degradation process in a plant. In this work, we monitored bacterial charge in different wastewater treatment plants by flow cytometry, also evaluating chlorination effects on bacterial viability, both by flow cytometry and traditional plate counts. Maximum values of bacterial charge were registered in the aeration tank of all plants monitored. Cell viability did not show significant differences (p > 0.05) in samples collected in "before chlorination" and "wastewater effluent" treatment steps; this suggests that the chlorination was not able to decrease total viable bacterial charge. In this work, we discuss the need to improve microbiological analyses, both in terms of measuring other potential pathogens and of using new methodological approaches in the traditional evaluation of the microbiological quality of effluents.     

Arsenic speciation in marine fish and shellfish from American Samoa

We speciated arsenic compounds in marine fish and shellfish from two islands of the United States Territory of American Samoa in the South Pacific, and found that inorganic arsenic occurred as a minor fraction. The proportion of inorganic arsenic was generally far below the levels of prevailing assumptions typically used in human health risk assessments when only total arsenic is analysed. Fish and shellfish were collected from Tutuila and Ofu between May 2001 and March 2002 (n=383 individual specimens, with 117 composites); sites were selected based on habitat type and were representative of those frequented by local fishers. These islands have moderately developed reef fish fisheries among artisanal fishers, are far removed from any industrial or mining sources of arsenic, and presented an opportunity to study arsenic variations in marine biota from un-impacted environments. Target species were from various trophic levels and are among those frequently harvested for human consumption. We found evidence that arsenic concentrated in some marine species, but did not tend to follow classic trophic patterns for biomagnification or bioaccumulation. For the majority of samples, inorganic arsenic was less than 0.5% of total arsenic, with only a few samples in the range of 1-5%, the latter being mollusks which are recognized to have unusually high arsenic levels in general. This work supports the importance of speciation analysis for arsenic, because of the ubiquitous occurrence of arsenic in the environment, and its variable toxicity depending on chemical form.     

Heavy metals: their pathway from the ground,groundwater and springs to Lake Góreckie (Poland)

The migration pathways of heavy metals derived from an area previously in agricultural use was investigated in the Wielkopolski National Park (mid-western Poland). The heavy metals involved (Cd, Cu, Cr, Pb, Ni and Zn) were determined in groundwater, the springs that feed Lake Góreckie and the lake itself. In order to show how the heavy metals may be set free and what is their biological availability, soil and sediment samples were subjected to single-stage extraction, using 0.01 M CaCl₂, 0.02 M EDTA, 0.005 M DTPA, 0.1 M HCl, 1 M HCl and de-ionised water. Varying metal concentrations were recorded in the water samples during the study period (from November 2009 to July 2010), usually with higher values in winter and lower ones in summer. The seasonal changes may be ascribed to natural processes taking place in the ground- and surface waters of Lake Góreckie. On the other hand, the concentration levels (mostly of Cd, Pb and Cr) are indicative of anthropogenic activity. It should be mentioned in this context that the highest metal concentrations were found in the soil layer. The concentrations were also found to exceed both the Polish and the World Health Organization water-quality standards. It appears that the soils are highly contaminated, mostly with cadmium. The long-lasting effect of acid precipitation in the area makes it possible for immobile forms to become mobile, thus facilitating further migration into the environment.     

Clinical significance of persistent amniotic fluid leakage after genetic amniocentesis

Chronic amniotic fluid leakage is a rare complication of genetic amniocentesis. Pregnancy outcomes in two such patients are presented and six previous cases reviewed. Although chorioamnionitis has not been reported, potentially serious complications may occur including an increased risk for pre-term delivery and fetal skeletal deformity. While conservative management of post-amniocentesis amniotic fluid leakage is advocated, patients should be advised of these risks.     

Concentrations and Source Characteristics of Airborne Carbonyl Compounds Measured Outside Urban Residences

Abstract

This paper presents the analysis of ambient air concentrations of 10 carbonyl compounds (aldehydes and ketones) measured in the yards of 87 residences in the city of Elizabeth, NJ, throughout 1999–2001. Most of these residences were measured twice in different seasons; the sampling duration was 48 hr each time. The authors observed higher concentrations for most of the measured carbonyl compounds on warmer days, reflecting larger contributions of photochemical reactions on warmer days. The estimated contributions of photochemical production varied substantially across the measured carbonyl compounds and could be as high as 60%. Photochemical activity, however, resulted in a net loss for formaldehyde. The authors used stepwise multiple linear regression models to evaluate the impact of traffic sources and meteorological conditions on carbonyl concentrations using the data collected on colder days (with lower photochemical activities). They found that the concentrations of formal-dehyde, acetaldehyde, acrolein, propionaldehyde, crotonaldehyde, benzaldehyde, glyoxal, and methylglyoxal significantly decreased with increasing distance between a measured residence and one or more major roadways. They also found significant negative associations between concentrations for most of the measured carbonyl compounds and each of the following meteorological parameters: mixing height, wind speed, and precipitation.     

Introduction of Participatory Conservation in Croatia, Residents’ Perceptions: A Case Study from the Istrian Peninsula

Croatia, like many other transition countries has undergone radical changes in its nature protection models. This paper discusses a historical overview, present situation and future possibilities for nature conservation in Croatia. A conservative top-down approach to nature protection was applied in the past in Croatia and is now being replaced by a prevalent bottom-up approach. Social context is crucial to introducing participatory conservation, therefore special concern is given to the perception of the local population towards protected area management in Istria as a case study in Croatia. Survey data were used to assess the conservation knowledge of local populations and their perception towards Protected Areas (PAs), leadership activities and management authorities in Istria County. This paper examines the perceptions of 313 residents living in and around six natural PAs located in Istria. The results revealed a moderate general knowledge about PAs in Istria and environmental issues, and a low awareness of institutions managing PAs, eagerness to participate in the activities of PAs and general support for the conservation cause. Understanding the perception of local residents enables the creation of feasible, long-term strategies for the implementation of participatory conservation. The research identifies the need for greater human, technical and financial efforts to strengthen the management capabilities of local agencies responsible for PAs. The process of participatory conservation optimization in Croatia is underway and world experiences must be observed in order to create a congruent, site-specific model with the best possible results.