Polybrominated diphenyl ethers (PBDEs) in leachates from selected landfill sites in South Africa

The last few decades have seen dramatic growth in the scale of production and the use of polybrominated diphenyl ethers (PBDEs) as flame retardants. Consequently, PBDEs such as BDE -28, -47, -66, -71, -75, -77, -85, -99, -100, -119, -138, -153, -154, and -183 have been detected in various environmental matrices. Generally, in South Africa, once the products containing these chemicals have outlived their usefulness, they are discarded into landfill sites. Consequently, the levels of PBDEs in leachates from landfill sites may give an indication of the general exposure and use of these compounds. The present study was aimed at determining the occurrence and concentrations of most common PBDEs in leachates from selected landfill sites. The extraction capacities of the solvents were also tested. Spiked landfill leachate samples were used for the recovery tests. Separation and determination of the PBDE congeners were carried out with a gas chromatograph equipped with Ni63 electron capture detector. The mean percentage recoveries ranged from 63% to 108% (n=3) for landfill leachate samples with petroleum ether giving the highest percentage extraction. The mean concentrations of PBDEs obtained ranged from ND to 2670pgl(-1), ND to 6638pgl(-1), ND to 7230pgl(-1), 41 to 4009pgl(-1), 90 to 9793pgl(-1) for the Garankuwa, Hatherly, Kwaggarsrand, Soshanguve and Temba landfill sites, respectively. Also BDE -28, -47, -71 and BDE-77 were detected in the leachate samples from all the landfill sites; and all the congeners were detected in two of the oldest landfill sites. The peak concentrations were recorded for BDE-47 at three sites and BDE-71 and BDE-75 at two sites. The highest concentration, 9793+/-1.5pgl(-1), was obtained for the Temba landfill site with the highest BOD value. This may suggest some influence of organics on the level of PBDEs. Considering the leaching characteristics of brominated flame retardants, there is a high possibility that with time these compounds may infiltrate into the groundwater around the sites since most of the sites are not adequately lined.     

Trace metals, anions and polybromodiphenyl ethers in settled indoor dust and their association

Contaminants in settled indoor dust are potentially health hazardous to human. Thus, identification and quantification of toxic chemicals in settled indoor dust is of great concern. In this study, the levels of major anions ( $ \mathrm{C}{{\mathrm{l}}^{-}},\mathrm{N}{{\mathrm{O}}_2}^{-},\mathrm{B}{{\mathrm{r}}^{-}},\mathrm{N}{{\mathrm{O}}_3}^{-},\mathrm{P}{{\mathrm{O}}_4}^{3-}\,\mathrm{and}\,\mathrm{S}{{\mathrm{O}}_4}^{2- } $ ), trace metals (Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, As and Pb) and polybromodiphenyl ethers (PBDEs) in settled office and home dust were determined and correlations between the contaminants investigated. Depending on the available materials in both microenvironments, the most possible sources were identified. The results showed that the settled office dusts (n?=?6 pooled samples from 85 offices) were more contaminated than home dusts (n?=?8 homes). For anions, $ \mathrm{S}{{\mathrm{O}}_4}^{2- } $ and Cl^– accounted for 87 and 97 % of the total office and home dust contaminants, respectively. For trace metals, Fe, Cu, Zn and Mn, accounted for 98 % of the contaminants in both office and home dust samples. Fe exhibited the highest percentage of 76.7 and 87.3 % in office and home dust samples, respectively. For PBDEs, the mean concentrations detected in office and home dust ranged between 5.8–86.3 and 1.5–20.6 ng?g^?1, respectively. The log-transformed correlation between the total concentrations of trace metals and major anions detected in offices and homes was positive for offices and negative for homes with a statistically significant values (r?=?0.73, p?<?0.01; r?= ?0.22, p?<?0.01, respectively). The daily exposure rates determined for the most hazardous such as As, Cd, Pb and PBDEs congeners, relative to the individual concentrations reported in the literature in settled indoor dust, were found very lower. Therefore, maybe it is possible to expect less potential health risk. Investigation of formation of coordination compounds between trace metals and PBDEs congeners is possible; however, this requires further study.     

Downgrading,Downsizing, Degazettement,and Reclassification of Protected Areas in Brazil

Protected areas (PAs) are key elements for biodiversity conservation and ecosystem services. Brazil has the largest PA system in the world, covering approximately 220 million ha. This system expanded rapidly in the mid‐1990s to the mid‐2000s. Recent events in Brazil, however, have led to an increase in PA downgrading, downsizing, and degazettement (PADDD). Does this reflect a shift in the country's PA policy? We analyzed the occurrence, frequency, magnitude, type, spatial distribution, and causes of changes in PA boundaries and categories in Brazil. We identified 93 PADDD events from 1981 to 2012. Such events increased in frequency since 2008 and were ascribed primarily to generation and transmission of electricity in Amazonia. In Brazilian parks and reserves, 7.3 million ha were affected by PADDD events, and of these, 5.2 million ha were affected by downsizing or degazetting. Moreover, projects being considered by the Federal Congress may degazette 2.1 million ha of PA in Amazonia alone. Relaxing the protection status of existing PAs is proving to be politically easy in Brazil, and the recent increase in frequency and extension of PADDD reflects a change in governmental policy. By taking advantage of chronic deficiencies in financial and personnel resources and surveillance, disputes over land tenure, and the slowness of the Brazilian justice, government agencies have been implementing PADDD without consultation of civil society. If parks and reserves are to maintain their integrity, there will need to be investments in Brazilian PAs and a better understanding of the benefits PAs provide. Degradación, Reajuste, Eliminacióm de las Listas y Reclasificación de Áreas Protegidas en Brasil     

Children's Experience of Conflict Related Emergencies: Some Implications for Relief Policy and Practice

This paper challenges the limited models of childhood, conflict and relief which determine most humanitarian interventions targeting children in conflict related emergencies. In particular, it notes the tendency of relief programmes to focus on "spectacular" groups of children (orphans, child combatants and refugees) at the expense of larger child populations indirectly affected by conflict. This relief bias is attributed to an inappropriate 'apocalypse model' of conflict which sees relief interventions only as repair. The bias also lies in a mistakenly universalist model of childhood and a medical paradigm which pathologizes children's experience in conflict and characterizes children as passive victims rather than active survivors. The paper argues for greater recognition of the wider social experience of children in conflict, and for relief practice which takes account of childhood resilience and children's different roles and capacities in coping with conflict. Appropriate interventions must engage with the wide variety of indigenous coping mechanisms involving children and not simply replicate a standard package of relief interventions in every emergency, based on simplistic and universalist interpretations of children's experience of conflict.     

聚合物改性粉煤灰制备多孔复合材料及其性能研究

制备了高掺量粉煤灰为基质的聚乙烯醇/纤维素复合多孔材料。该复合材料制备过程简单易行,不需高温高压。通过XRF、XRD、FT-IR、SEM以及压汞法对该粉煤灰复合材料进行了表征和结构分析,探索了原料混合比例、干燥温度对样品结构和性能的影响。研究发现:聚乙烯醇可以有效提高该复合材料的无侧限抗压强度,纤维素可有效改善材料的孔隙结构;材料的孔隙主要来自水分蒸发过程中的气泡聚合,在外部不加压的条件下制备样品,需控制干燥温度对样品内部孔隙结构的影响。当粉煤灰含量为80%,聚乙烯醇含量为10%,纤维素含量为10%时,复合材料具有较好的孔隙率、孔隙结构、抗压强度和吸水性及保水性。有一定强度的以粉煤灰为基质的亲水性材料也适合作为吸附材料或滤料,未来可以进一步通过改善材料内部结构,以及活化功能性官能团以提高材料的综合性能,为粉煤灰的综合利用拓展途径。     

Recreational Portage Trails as Corridors Facilitating Non-Native Plant Invasions of the Boundary Waters Canoe Area Wilderness (U.S.A.)

Abstract:  Wilderness areas are protected and valued in part for recreation; recreational use, however, can negatively impact these areas. In particular, recreational use can facilitate transport of non-native propagules and create open sites for establishment of non-native species. We examined the role of recreational portage trails in the introduction and establishment of non-native plants into the Boundary Waters Canoe Area Wilderness of northern Minnesota (U.S.A.). On 20 portages, we sampled non-native plant richness and cover at four distances (0, 10, 25, and 50 m) from trails. Non-native richness and cover were not related to distance from wilderness entry point. Non-native richness and cover were, however, negatively related to distance from trails. All six non-native species we observed were either directly on or within 1 m of trails. These results suggest that recreational trails act as corridors facilitating invasions of non-native plants into wilderness areas. It remains unclear, however, whether these effects are caused by dispersal of propagules, creation of bare ground, or changes in the native plant community.     

The Lower Niger River dredging and indigenous wetland livelihoods in Nigeria: the Anam communities in Ugbolu, Delta State, as a case study

The article explored systemic tendencies for state-led development projects in Nigeria, such as the recently concluded Lower Niger River dredging, to compromise indigenous livelihoods. Development research methods were sensitized with James Ferguson’s antipolitics machine critique and used to elicit participants’ perspectives of the structuring role of the Niger River on their livelihoods, their evaluation of the participatory content of the project and potential project effects on their livelihoods. Participants claimed the Niger River system singularly structures their livelihoods by facilitating recession farming and fishing. In relation to the participatory content and (un)anticipated effects of the dredging project, key informants insisted that it was undemocratically conceived and executed; that the project will reduce the annual Niger River flood, opportunities for recession farming and fishing, impoverish them, induce involuntary migration, and inter-community conflict. Consequently, an inverse relationship was inferred between technicist development programmes or projects conceived and managed by agents of the Nigerian State and the alleged beneficiaries’ versions and experience of structural change. The author also found that the project was exploited by Nigerian development elites to redefine complex regional underdevelopment challenges as infrastructural deficit and relocate discursive blame for underdevelopment from the state and multinational corporations to riverside communities, their cultures and wet ecologies.     

A comparative study of modified and unmodified maize tassels for removal of selected trace metals in contaminated water

Powdered maize tassels were studied and found to exhibit metal sorption properties due to the availability of functional groups. The tassels have a high amount of soluble organic substances that can dissolve in aqueous media, contributing to secondary pollution during a water treatment process. A chelating agent was chemically attached on the maize tassels with a view to increase the sorption capacity, minimize leaching, and enhance the tassels’ stability. Thermogravimetric analysis confirmed that modification improved their thermal stability to withstand temperatures above 600°C as well as reduced the “secondary pollution”. The modified sorbent was employed for the sorption of lead, copper, and cadmium ions in both the model solutions and the real samples. The contact time and pH were optimized after which Langmuir and Freundlich isotherms were applied to the data. The sorption capacities for Cu²⁺, Cd²⁺, and Pb²⁺ improved from 3.4, 0.8, and 1.7?g?kg^?1, respectively, to 6.3, 2.6, and 2.6?g?kg^?1 in the same order. The sorbent was shown to remove up to 95% of the metals in less than 10 min. This study has a potential application for the remediation of polluted waters.     

Determination of urinary lead in school children in Manzini, Swaziland, Southern Africa

Two hundred and fifty-seven urine samples collected from school children living in the Manzini region, Swaziland, were analysed for lead (Pb), using a graphite furnace atomic absorption spectrometer. The mean urine lead concentration for the urban schools ranged from 0.038–0.040 gml^–1, while that for the rural schools ranged from 0.017–0.022 gml^–1. The observed range shown by the urban schools was above the normal (for healthy humans) urine lead concentration of 0.035 gml^–1. However, the mean urine lead concentration for the rural schools was found to be lower than this value. The mean urine lead concentration for the urban schools was significantly higher than that of the rural schools. The differences in the mean urine lead concentrations for boys and girls from both urban and rural schools were found not to be significant, despite the higher values shown by the girls. The difference in lead concentrations between urban and rural schools in Manzini was thought to be due to the traffic density within the urban area.     

Assessment of Lead Exposure in Thohoyandou, South Africa

Lead levels in different environmental media (soil, grass leaves, water, ceramics, pencil, paint, crayons and cosmetics) were determined to assess the major sources of lead exposure in Thohoyandou, South Africa. Soil and plant leaves were used as indicators of Pb pollution from vehicle exhaust emissions. After digestion with concentrated acids (HNO₃, HCl and HClO₄) Pb concentrations were determined in triplicate using a flame atomic absorption spectrometer. The mean Pb concentrations at the kerb of selected busy roads were 205.5 ± 90, 273.0 ± 90 and 312.8 ± 81 μg g⁻¹ and 154.7 ± 67, 182.9 ± 76 and 240.6 ± 66 μg g⁻¹ for soil and plant leaves (dry weight) respectively. These concentrations were substantially higher than the values found on soils 50 m away from the roads (97.4 ± 11 μg g⁻¹). Pb concentrations in plants collected further away from the road (50 m) were substantially lower (71.8 ± 9.0 μg g⁻¹). The observed levels on soil are lower than the UK critical value of 500 μg g⁻¹ for gardens and allotments; and 2000 μg g⁻¹ for parks and open space as well as the Canadian values for agricultural (375 μg g⁻¹), residential (500 μg g⁻¹ and industrial (1000 μg g⁻¹). From these data it was clear that Pb concentrations in soil samples were substantially higher than the levels obtained for plant leaves. The Pb levels in green crayons, blue crayons, pencils (from China & Germany), were 10650 ± 75.2, 8200 ± 52.4, 1160 ± 50.2, 79 ± 10.1 μg g⁻¹ for the inner contents; and 4870 ± 58.1, 5650 ± 55.5, 1950 ± 46.6, 60 ± 12.9 μg g⁻¹ for the outer surface paint respectively. The ceramics showed Pb levels of 630 ± 50.3 μg g⁻¹ (saucer) and 560 ± 32.2 μg g⁻¹ (cup), while the inner contents and outer surface paint showed 480 ± 32.4 and 318 ± 21.2 μg g⁻¹ of Pb respectively. Early morning tap water flush gave a Pb level of 20.6 ± 5.6 μg Pb l⁻¹. This value is higher than the WHO and FDA maximum permissible concentrations of 10 μg l⁻¹ and 15 μg l⁻¹ respectively.