Comparison of manufactured and black carbon nanoparticle concentrations in aquatic sediments

In this paper, we show that concentrations of manufactured carbon-based nanoparticles (MCNPs) in aquatic sediments will be negligible compared to levels of black carbon nanoparticles (BCNPs). This is concluded from model calculations accounting for MCNP sedimentation fluxes, removal rates due to aggregation or degradation, and MCNP burial in deeper sediment layers. The resultant steady state MCNP levels are compared with BCNP levels calculated from soot levels in sediments and weight fractions of nanosized fractions of these soot particles. MCNP/BCNP ratios range from 10⁻⁷ to 10⁻⁴ (w:w). This suggests that the often acclaimed effect of MCNPs on organic pollutant binding and bioavailability will likely be below the level of detection if natural BCNPs are present, even if binding to MCNP is one to two orders of magnitude stronger than to BCNPs. Furthermore, exposure and toxic effects of MCNPs in sediments and soils will be negligible compared to that of BCNPs.     

Absence behavior as traffic crash predictor in bus drivers

Problem

Various indicators of health have been shown to be associated with traffic crash involvement. As general health is also related to absence from work, the latter variable may be more strongly related to crashes, especially for professional drivers.

Method

Bus driver absence from work was analyzed in association with their crash records. Two British samples and one Swedish sample were used.

Results

One of the British samples yielded fair correlations between crash record and absence, while for the other the effect was restricted to the first three months of driving. The Swedish data had effects in the expected direction but these were not significant.

Discussion

The use of an indirect, overall measurement of health, may be a viable method for predicting the traffic crash involvement for professional drivers, although replications are needed in larger samples and other populations.

Impact on industry

The use of absence records for the identification of at risk drivers would seem to be a simple and useful method for companies with major fleets, and it also shows the importance of promoting employee health and well being at work as a potential method of reducing the cost, not only of absenteeism, but also of crashes in company vehicles.     

Biomonitoring of pyrethroid exposure among rural and urban populations in northern Poland

The aim of this study was to determine for the first time in Poland, levels of exposure to synthetic pyrethroids in preschool and school age children and their parents living in urban and rural areas. For this purpose concentrations of pyrethroid metabolites: 3-phenoxybenzoic acid (3-PBA), 2,2-dibromovinyl-2,2-dimethylcyclopropanecarboxylic acid (Br₂CA), cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (cis-Cl₂CA) and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (trans-Cl₂CA) were determined in 374 urine samples using a validated GC–MS method.     

Polychlorinated biphenyls in vacuum dust and blood of residents in 20 Wisconsin households

Human exposure to PCBs is nearly universal in North America. While most exposure can be linked to consumption of contaminated fish, detection of PCBs in non-fish eating populations suggests that other routes of exposure including inhalation of PCB-laden particles or volatile congeners, ingestion of contaminated soil or dust, or dermal absorption following direct contact are also important. In an effort to assess the role of the residential environment as a source of exposure, vacuum dust was collected from the homes of 26 Wisconsin residents whose serum PCB levels had been measured approximately 2 years earlier. More than 60 congeners were detected in dust with all of the samples containing congeners 101, 110, 138 and 153. Total PCB levels ranged from 8.8 to 1186 ng g⁻¹ with levels being highest in vacuum dust from homes built between 1959 and 1970. Total PCB levels ranged from 0.05 to 8.34 μg L⁻¹ in serum collected from the adults living in these households, with congeners 138, 153 and 180 predominating. Hexa- and hepta-chlorinated biphenyls comprised 73% of the total residues detected in serum. However, most of the residues found in dust were lower chlorinated congeners with tetra- and penta-chlorinated biphenyls being dominant. Following log transformation, a positive association was found between serum and house dust PCB levels. This association was stronger among infrequent consumers of Great Lake fish, but of borderline statistical significance. This exploratory study suggests that house dust may be a significant source of exposure to PCBs and supports the need for further investigations.     

Measuring combined exposure to environmental pressures in urban areas: an air quality and noise pollution assessment approach

This study presents a methodological scheme developed to provide a combined air and noise pollution exposure assessment based on measurements from personal portable monitors. Provided that air and noise pollution are considered in a co-exposure approach, they represent a significant environmental hazard to public health. The methodology is demonstrated for the city of Thessaloniki, Greece. The results of an extensive field campaign are presented and the variations in personal exposure between modes of transport, routes, streets and transport microenvironments are evaluated. Air pollution and noise measurements were performed simultaneously along several commuting routes, during the morning and evening rush hours. Combined exposure to environmental pollutants is highlighted based on the Combined Exposure Factor (CEF) and Combined Dose and Exposure Factor (CDEF). The CDEF takes into account the potential relative uptake of each pollutant by considering the physical activities of each citizen. Rather than viewing environmental pollutants separately for planning and environmental sustainability considerations, the possibility of an easy-to-comprehend co-exposure approach based on these two indices is demonstrated. Furthermore, they provide for the first time a combined exposure assessment to these environmental pollutants for Thessaloniki and in this sense they could be of importance for local public authorities and decision makers. A considerable environmental burden for the citizens of Thessaloniki, especially for VOCs and noise pollution levels is observed. The material herein points out the importance of measuring public health stressors and the necessity of considering urban environmental pollution in a holistic way.     

An evaluation of lead concentrations in imported hot sauces

In the last decade, the U.S. Food and Drug Administration (FDA) has issued several warnings and recalls for food products that exceed FDA standards for lead. Products containing chili peppers and salt were often suspected as sources of lead contamination, and included items such as candy that are routinely investigated. However, products such as hot sauces that contain similar ingredients have not been the focus of evaluations. This study quantified lead concentrations in imported hot sauces, evaluated product compliance to existing United States standards, and calculated potential dietary lead exposure for children using the Integrated Exposure Uptake Biokinetic Model. Finally, recommendations for reducing the risk of lead exposure from hot sauces are provided. Twenty-five (25) bottles of imported hot sauces manufactured in Mexico and South America were purchased in Clark County, Nevada. All hot sauces were analyzed for lead concentrations, pH, and leaded packaging. Hot sauces were analyzed by inductively coupled plasma mass spectrometry and packaging was analyzed using x-ray fluorescence technology. Four brands of hot sauces (16%) exceeded 0.1 ppm lead, the current FDA action level for lead in candy. Hot sauces with lead concentrations >0.1 ppm lead contained salt and were manufactured in Mexico. Subsequent analysis of additional lots of hot sauces exceeding 0.1 ppm lead revealed inconsistent lead concentrations between and within manufacturer lots. The lead concentrations of the plastic hot sauce lids ranged from below the limit of detection to 2,028 ppm lead. There was no association between lead concentrations in hot sauces and pepper type. These results indicate the need for more rigorous screening protocols for products imported from Mexico, the establishment of an applicable standard for hot sauce, and resources to allow for the enforcement of existing food safety policies. The data reported herein represent the first known investigation of lead concentrations in hot sauces.     

Minimizing drift and exposure from knapsack sprayers

Abstract

An improved drift shield for attaching to the lance of conventional knapsack sprayer to reduce wind induced drift and operator exposure was designed and tested. The drift shield consists of a conical wire frame covered with polythene and has an annular opening at the point of attachment to the lance which allows air to be drawn into the shield while spraying. Tests conducted with winds in the range of 1.25–5.75 m/s show that wind can increase the width of spray swath from an unshielded lance, up to 4.3 times the normal swath in no‐wind condition. Use of a conventional shield contained the swath width within 3.5 times and the improved shield restricted the swath width to 3.1 times the normal swath. Spray deposit from an unshielded lance, within the normal swath decreased to as low as 45%, due to wind effects. However, use of the conventional, and the improved shields enhanced the spray deposit to 54.2% and 68%, respectively. The improved drift shield improved the spray pattern displacement (SPD) significantly (P<0.05) compared with the conventional shield and the unshielded lance when the wind speed exceeded 1.25 m/s. The improved shield decreased the off target drift by as much as 63% compared with the unshielded spray. It also decreased the quantity of pesticide deposit on the operator's body by 41–84% and thereby reduced exposure and improved safety.     

A human health risk assessment of rare earth elements in soil and vegetables from a mining area in Fujian Province,Southeast China

Contaminated food through dietary intake has become the main potential risk impacts on human health. This study investigated concentrations of rare earth elements (REEs) in soil, vegetables, human hair and blood, and assessed human health risk through vegetables consumption in the vicinity of a large-scale mining area located in Hetian Town of Changting County, Fujian Province, Southeast China. The results of the study included the following mean concentrations for total and bio-available REEs of 242.92 ± 68.98 (135.85–327.56) μg g⁻¹ and 118.59 ± 38.49 (57.89–158.96) μg g⁻¹ dry weight (dw) in agricultural soil, respectively, and total REEs of 3.58 ± 5.28 (0.07–64.42) μg g⁻¹ dw in vegetable samples. Concentrations of total REEs in blood and hair collected from the local residents ranged from 424.76 to 1274.80 μg L⁻¹ with an average of 689.74 ± 254.25 μg L⁻¹ and from 0.06 to 1.59 μg g⁻¹ with an average of 0.48 ± 0.59 μg g⁻¹ of the study, respectively. In addition, a significant correlation was observed between REEs in blood and corresponding soil samples (R² = 0.6556, p < 0.05), however there was no correlation between REEs in hair and corresponding soils (p > 0.05). Mean concentrations of REEs of 2.85 (0.59–10.24) μg L⁻¹ in well water from the local households was 53-fold than that in the drinking water of Fuzhou city (0.054 μg L⁻¹). The health risk assessment indicated that vegetable consumption would not result in exceeding the safe values of estimate daily intake (EDI) REEs (100−110 μg kg⁻¹ d⁻¹) for adults and children, but attention should be paid to monitoring human beings health in such rare earth mining areas due to long-term exposure to high dose REEs from food consumptions.     

Air quality and deposition of trace elements in Didouche Mourad, Algeria

Total suspended particulate matter and deposition fluxes of particles were investigated in the town of Didouche Mourad which is located 13 km north of Constantine. Samples of air particulate matter were collected at one site located in the heart of the town and situated 3 km north of a cement plant. Samples were collected from 2 November 2002 to 28 April 2003 every 3 days using a high volume air sampler. Sampling intervals were 24 h in all cases. During the same period, samples of dust fallout were collected at the same site. Samples were collected at 30-day intervals. Lead, chromium, manganese, nickel, copper, cobalt and cadmium deposition fluxes were measured and both the soluble and insoluble fractions were determined. Furthermore, the information gathered by this study was correlated with the corresponding hourly weather data provided by a weather station installed at the study station. The possible sources for dust and trace metals were analyzed by comparing average contributions of wind aspects to the concentrations and depositions of mass and chemical species with the average frequencies of wind direction. The mean concentration was 300 μg/m³. The average dust deposition rate through the period of study was 221 mg/(m².day). Results indicate that anthropogenic sources contribute greatly to trace elements. An exposure assessment to the heavy metals taking into account the inhalation route and soil dust ingestion was carried out and allowed direct comparison of trace metal intakes via these routes.     

生活垃圾焚烧发电厂周边环境二噁英污染水平及人群暴露评估

选取某典型生活垃圾焚烧发电厂为研究对象,监测其周边环境空气、土壤、地下水、农作物等环境介质中二噁英的浓度水平,初步评估周边人群二噁英暴露水平。研究结果表明,该厂周边环境空气、土壤、地下水中二噁英测定值分别为0. 236 pg TEQ/m3～0. 331 pg TEQ/m3、1. 94 ng TEQ/kg～2. 71 ng TEQ/kg、0. 17 pg TEQ/L～0. 26 pg TEQ/L,企业排放的二噁英对周边环境影响较小;成人和儿童在暴露介质中摄入二噁英总量分别为0. 959 pg TEQ/(kg·d)和1. 59 pg TEQ/(kg·d),均低于4 pg TEQ/(kg·d)的标准,经大米和面粉摄入二噁英的量超过总暴露量的90%,提示食物是人群二噁英暴露的主要介质。