Carry-over of dietary organochlorine pesticides, PCDD/Fs, PCBs, and brominated flame retardants to Atlantic salmon (Salmo salar L.) fillets

Information on carry-over of contaminants from feed to animal food products is essential for appropriate human risk assessment of feed contaminants. The carry-over of potentially hazardous persistent organic pollutants (POPs) from feed to fillet was assessed in consumption sized Atlantic salmon (Salmo salar). Relative carry-over (defined as the fraction of a certain dietary POP retained in the fillet) was assessed in a controlled feeding trial, which provided fillet retention of dietary organochlorine pesticides (OCPs), dioxins (PCDD/Fs), polychlorinated biphenyls (PCBs), and brominated flame retardants (BFRs). Highest retention was found for OCPs, BFRs and PCBs (31-58%), and the lowest retentions were observed for PCDD/Fs congeners (10-34%). National monitoring data on commercial fish feed and farmed Atlantic salmon on the Norwegian market were used to provide commercially relevant feed-to-fillet transfer factors (calculated as fillet POP level divided by feed POP level), which ranged from 0.4 to 0.5, which is a factor 5-10 times higher than reported for terrestrial meat products. For the OCP with one of the highest relative carry-over, toxaphene, uptake and elimination kinetics were established. Model simulations that are based on the uptake and elimination kinetics gave predicted levels that were in agreement with the measured values. Application of the model to the current EU upper limit for toxaphene in feed (50 μg kg⁻¹) gave maximum fillet levels of 22 μg kg⁻¹, which exceeds the estimated permissible level (21 μg kg⁻¹) for toxaphene in fish food samples in Norway.     

食物安全:基于食品系统理论的探讨

在经济发展、消费升级、资源短缺和环境问题凸显的新的外部环境背景下,本文引入了国外新兴的食品系统理论,探讨并提出了可持续的食物安全保障的新观念.食物安全始终是中国经济发展、社会稳定和国家自立的基础.国内多数学者仍然用30年前食物匮乏时期的思路来研究现代的食物安全问题,其结果导致研究结论与现实情况不符.如何在节约资源、减少浪费的同时又能够满足人们不断升级的食物消费需求,是对未来食物安全保障的新要求.本文首先分析了我国食物安全研究的现状,指出了不足和问题,然后引入国外新兴的食品系统理论,在探讨其概念内涵的基础上,剖析了食品系统与食物安全的关系,影响食物安全的因素和研究视角,并进一步提炼出基于食品系统理论的新的食物安全保障观念,为我国研究食物安全提供借鉴.     

Capacity building for food justice in England: the contribution of charity-led community food initiatives

This paper discusses the extent to which charity-led initiatives can contribute to capacity building for food justice in England. The paper draws on evaluations of two projects run by the charity Garden Organic: the Master Gardener Programme, operating a network of volunteers who mentor households, schools and community groups to support local food growing, and the Sowing New Seeds programme, which engages “Seed Stewards” to work with communities to encourage the growing and cooking of “exotic” crops. Based on qualitative data about peoples’ motivations for participation and the benefits that are experienced, we interpret these projects as examples of capacity building for food justice. We suggest that whilst currently depoliticised, the “quiet” process of reskilling and awareness raising that occurs through shared gardening projects could have transformative potential for people’s relationship with food. Finally, we use our findings to raise critical questions and propose future research about food justice concepts and practices.     

Arsenic rich iron plaque on macrophyte roots - an ecotoxicological risk?

Arsenic is known to accumulate with iron plaque on macrophyte roots. Three to four years after the Aznalcóllar mine spill (Spain), residual arsenic contamination left in seasonal wetland habitats has been identified in this form by scanning electron microscopy. Total digestion has determined arsenic concentrations in thoroughly washed ‘root + plaque’ material in excess of 1000 mg kg⁻¹, and further analysis using X-ray absorption spectroscopy suggests arsenic exists as both arsenate and arsenite. Certain herbivorous species feed on rhizomes and bulbs of macrophytes in a wide range of global environments, and the ecotoxicological impact of consuming arsenic rich iron plaque associated with such food items remains to be quantified. Here, greylag geese which feed on Scirpus maritimus rhizome and bulb material in areas affected by the Aznalcóllar spill are shown to have elevated levels of arsenic in their feces, which may originate from arsenic rich iron plaque.     

Use of a food web model to evaluate the factors responsible for high PCB fish concentrations in Lake Ellasjøen, a high Arctic Lake

Background, aim, and scope

Lake Ellasjøen, located in the Norwegian high arctic, contains the highest concentrations of polychlorinated biphenyls (PCBs) ever recorded in fish and sediment from high arctic lakes, and concentrations are more than 10 times greater than in nearby Lake Øyangen. These elevated concentrations in Ellasjøen have been previously attributed, in part, to contaminant loadings from seabirds that use Ellasjøen, but not Øyangen, as a resting area. However, other factors, such as food web structure, organism growth rate, weight, lipid content, lake morphology, and nutrient inputs from the seabird guano, also differ between the two systems. The aim of this study is to evaluate the relative influence of these factors as explanatory variables for the higher PCB fish concentrations in Ellasjøen compared with Øyangen, using both a food web model and empirical data.

Methods

The model is based on previously developed models but parameterized for Lakes Ellasjøen and Øyangen using measured data wherever possible. The model was applied to five representative PCB congeners (PCB 105, 118, 138, 153, and 180) using measured sediment and water concentrations as input data and evaluated with previously collected food web data.

Results

Modeled concentrations are within a factor of two of measured concentrations in 60% and 40% of the cases in Lakes Ellasjøen and Øyangen, respectively, and within a factor of 10 in 100% of the cases in both lakes. In many cases, this is comparable to the variability associated with the data as well as the efficacy of the predictions of other food web model applications.

Discussion

We next used the model to quantify the relative importance of five major differences between Ellasjøen and Øyangen by replacing variables representing each of these factors in the Ellasjøen model with those from Øyangen, in separate simulations. The model predicts that the elevated PCB concentrations in Ellasjøen water and sediment account for 49%–58% of differences in modeled fish PCB concentrations between lakes. These elevated sediment and, to a lesser extent, water concentrations in Ellasjøen are due to PCB loadings from seabird guano. However, sediment–water fugacity ratios of PCBs are consistently greater in Ellasjøen compared with Øyangen, which suggests that internal lake processes also contribute to differences in sediment and water concentrations. We hypothesize that the nutrients associated with guano influence sediment–water fugacity ratios of PCBs by increasing the stock of pelagic algae. As both these algae and the guano settle, their organic carbon content is degraded faster than PCBs, which causes an extra magnification step in Ellasjøen before these detrital particles are consumed by benthic organisms, which are in turn consumed by fish. The model predicts that the remaining ～50% of the differences in PCB concentrations observed between the fish of these lakes are due to other subtle differences in their food web structures.

Conclusions

In conclusion, based on the results of a food web model, we found that the most dominant factors influencing the higher PCB fish concentrations in Lake Ellasjøen compared with Øyangen are the higher sediment and water concentrations in Ellasjøen, caused by seabird guano. Together, sediment and water are predicted to account for 49%–58% of differences in fish concentrations between lakes. Although seabird guano provides a source of nutrients to the lake, in addition to contaminants, empirical data and indirect model results suggest that nutrients are not leading to decreased bioaccumulation, in contrast to what has been observed in temperate, pelagic food webs.

Recommendations and perspectives

The results of this study emphasize the importance of considering even small differences in food web structure when comparing bioaccumulation in two lakes; although the food web structures of Ellasjøen and Øyangen differ only slightly, the model predicts that these differences account for most of the remaining ～50% of the differences in PCB fish concentrations between the two lakes. This study further demonstrates the utility of food web models as we were able to predict and tease apart the influence of various factors responsible for the elevated concentrations in the fish from Lake Ellasjøen, which would have been difficult using the field data alone.     

Biomagnification of anthropogenic and naturally-produced organobrominated compounds in a marine food web from Sydney Harbour, Australia

Polybrominated diphenyl ethers (PBDEs) and naturally-produced organobrominated compounds, such as methoxylated PBDEs (MeO-PBDEs), have been scarcely studied in the Southern Hemisphere. Yet, sources of the latter group of compounds were found in Southern regions, specifically in Australia. The environmental distribution and biomagnification potential of organobrominated compounds were therefore investigated in a representative aquatic food chain (invertebrates and fish) from the Sydney Harbour, Australia. Mean PBDE concentrations ranged from 6.4 ng/g lipid weight (lw) in squid to 115 ng/g lw in flounder. BDE 47 was the dominant congener, followed by BDE 100. Mean levels of MeO-PBDEs (sum of congeners 2’-MeO-BDE 68 and 6-MeO-BDE 47) were as high as 110 ng/g lw in tailor, with a slight dominance of 2’-MeO-BDE 68. Polybrominated hexahydroxanthene derivates (PBHDs), another class of naturally-produced compounds, were found at variable concentrations and ranged from 4.7 ng/g lw in fanbelly and 146 ng/g lw in tailor. The tribrominated PBHD isomer dominated in the samples, except for luderick and squid. The lower levels of PBDEs found in luderick from the harbour compared to those obtained from the upper Parramatta River indicated a terrestrial (anthropogenic) origin of PBDEs, while the higher levels of MeO-PBDEs and PBHDs in the samples from the harbour confirmed the marine (natural) origin of these compounds. The highest trophic magnification factor (TMF) was found for sum PBDEs (3.9), while TMFs for sum MeO-PBDEs and sum PBHDs were 2.9 and 3.4, respectively. This suggests that biomagnification occurs in the studied aquatic food chain for anthropogenic brominated compounds, but also for the naturally-produced organobromines.     

Food chain transfer of cadmium and lead to cattle in a lead–zinc smelter in Guizhou, China

Cadmium (Cd) and Lead (Pb) are environmental pollutants. Environmental samples and bovine tissues were collected from the areas around a lead–zinc smelter in Guizhou, China for Cd, Pb, zinc (Zn) and copper (Cu) analysis. Cd in soil (10 mg/kg) and feed (6.6 mg/kg) from the polluted areas was 10 times higher than the Chinese Standards, resulting in higher Cd in bovine kidney (38 mg/kg) and liver (2.5 mg/kg). Pb in feed (132 mg/kg) from the polluted area was much higher than unpolluted areas, causing higher Pb levels in bovine tissues. Environmental Zn was elevated, but bovine tissue Zn was normal. Cu in bovine liver decreased with increased Cd and Pb. Metals in drinking water and in bovine muscle were within the Standard range. Thus, in the areas of this lead–zinc smelter, the environment has been contaminated with Cd and Pb, which has been transferred to cattle through the food chain.     

Choosing a Food Future: Differentiating Among Alternative Food Options

This article examines the diversity of food networks that fit within the alternative food system of the United States. While farmers’ markets, community supported agriculture schemes, and corporate organic food markets all fit within the alternative food system, they differ greatly in the conventions and beliefs that they represent. The alternative food system has divided into two movements: corporate, weak alternative food networks; and local, strong alternative food networks. The weak corporate version focuses on protecting the environment; however, it neglects issues concerning labor standards, animal welfare, rural communities, small-scale farmers, and human health. Local, strong alternative food networks not only assure environmental protection, but they also address the issues that weak alternatives neglect. Using three case studies from the Washington, D.C. metro area, the author explains that strong alternative food networks are better suited to create social and political change because they challenge the foundations of the conventional food system: standardized and generic products, price-based competition, consolidated power, and global scale. To affect true social and political change in the United States, the author recommends supporting strong alternative food networks by creating the requisite cultural and political space for them to succeed.     

大型活动生物恐怖应急处置研究与系统开发

针对非传统安全威胁的现状及其应急处置中的主要问题,以典型的非传统安全事件-大型活动举办过程中生物恐怖事件为背景,通过比较分析,给出了生物恐怖的定义;从大型活动生物恐怖应急指挥与处置的角度,通过应急处置业务流程分析,提出了大型活动生物恐怖事件应急处置的系统框架;根据系统框架和处置功能分析,基于三维GIS和AJAX技术开发了大型活动生物恐怖应急处置原型系统,对复杂的应急处置体系进行了分层模块化和可视化,可为应急救援部门制定更为详细的救援方案和应急决策提供技术参考。     

水资源问题安全化及其本质

从安全问题、安全化入手,探讨水资源问题安全化,解释了安全、安全问题及安全化的内涵;指出水资源问题来源于人类活动与水资源之间不和谐的运动,及其运动的逐渐升级,将产生一些危害性较大的水资源问题,水资源安全问题是水资源问题严重化的终极形态,其安全化是水资源问题转变为水资源安全问题的过程。在水资源安全化过程中,水资源问题是起点,安全化是过程,水资源安全问题是结果和终点。研究结果表明,水资源问题安全化的本质是水资源的稀缺性,安全的基础是健康的水循环。