Degradation rates of aged petroleum hydrocarbons are likely to be mass transfer dependent in the field

Evidence for on site biodegradation may be difficult to provide at heterogeneous sites without additional experiments in controlled laboratory conditions. In this study, microbial activities measured as CO₂ and CH₄ production were compared in situ, in intact soil cores and in bottle microcosms containing sieved soils. In addition, biodegradation rates were determined by measuring the decrease in petroleum hydrocarbon concentrations at 7°C in aerobic and anaerobic conditions. Elevated concentrations of CO₂ and CH₄ in the soil gas phase indicated that both the aerobic and anaerobic microbial activity potentials were high at the contaminated site. Aerobic and anaerobic microbial degradation rates in laboratory experiments of petroleum hydrocarbons were highest in soils from the most contaminated point and degradation in the aerobic and anaerobic microcosms was linear throughout the incubation, indicating mass-transfer-dependent degradation. Different results for microbial activity measurements were obtained in laboratory studies depending on pretreatment and size of the sample, even when the environmental conditions were mimicked. These differences may be related to differences in the gas exchange rates as well as in changes in the bioavailability of the contaminant in different analyses. When predicting by modeling the behavior of an aged contaminant it is relevant to adapt the models in use to correspond to conditions relevant at the contaminated sites. The variables used in the models should be based on data from the site and on experiments performed using the original aged contaminant without any additions.     

20世纪赫尔辛基海域富营养化的历史浮游生物群落的长期分析

本研究论文的目的是展示赫尔辛基海区近l00年环境调查的连续历史以及该海区营养水平的变化.该调查是基于对原始的浮游生物和气象资料的重新研究,原理是,尽管方法上发生了变化,浮游生物群落的富营养化是可以被检测的.20世纪初,赫尔辛基附近的海湾处于中度富营养到超营养的状态.在海湾的开发上,无论就退化还是恢复而言,都存在着巨大的差异.废水处理的效率,特别是入海排污口的使用在减少赫尔辛基海湾地区富营养化方面发挥了作用.     

Occupational injuries of immigrant and Finnish bus drivers

Problem

With baby boomers reaching retirement age, Western countries may need more immigrant workers to ensure productivity. Many studies have suggested a higher occupational injury frequency among immigrant workers, which could considerably reduce their contribution to society. The aim of this study was to examine whether immigrant workers have a higher injury frequency compared to Finnish workers when performing the exact same tasks under the same working conditions.

Method

A total of 176 Finnish and 130 immigrant bus drivers were asked about their occupational injuries during the past 12 months via a questionnaire. In addition, the data contained 134 injuries reported by the transport firm to an insurance company.

Results

There was no significant difference in reporting occupational injuries by self-reporting or by company-records. Because there were more accident-repeaters among Finnish drivers, their injury frequency (114) was higher than that of immigrant drivers (78).

Application/Impact

This study showed that immigrant workers did not have a higher injury frequency than other workers when they worked in the exact same conditions. Immigrant workers can work as safely as native-Finnish workers, when their working conditions and job contracts are at the same level as those of the original population. Immigrant workers can compensate for the shortage of workforce caused by an aging population.     

Educational status and organizational safety climate: Does educational attainment influence workers’ perceptions of workplace safety?

From a practical perspective, understanding the impact of education on perceptions of workplace safety would benefit management’s decisions regarding workers’ adaptability, general work effectiveness, accident frequency, implementation of safety management policies, and handling of education-related accident characteristics. The current study thus examined the relationship between educational attainment and (i) safety perception, (ii) job satisfaction, (iii) compliance with safety management policies, and (iv) accident frequency. Participants were Ghanaian industrial workers (N = 320) categorized into four educational groups based on their responses: basic education 50% (n = 159); secondary education, n = 98 (30%); vocational/professional education, 17% (n = 56); and university education, 3% (n = 7). Workplace safety perception was assessed with Hayes et al.’s 50-item Work Safety Scale (WSS): a scale that effectively captures the dimensions identified by safety experts to influence perceptions of workplace safety. Multivariate analysis (MANOVA) was used to test for differences of statistical significance. Posterior comparison with t-test consistently revealed significant differences between the two higher-educated cohorts and their lower-educated counterparts. The results indicated a positive association between education and safety perception. Higher-educated workers recorded the best perceptions on safety, indicated the highest level of job satisfaction, were the most compliant with safety procedures and recorded the lowest accident involvement rate.