Browsing by Author "Breivik, Knut"

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    Mercury in Air and Soil on an Urban-Rural Transect in East Africa
    (Royal Society of Chemistry, 2022) Nipen, Maja; Jørgensen, Susanne J.; Bohlin-Nizzetto, P.; Borg˚a, Katrine; Breivik, Knut; Mmochi, Aviti J.; Mwakalapa, Eliezer B.; Quant, M. I.; Schlabach, Martin; Vogt, Rolf D.; Wania, Frank
    There are large knowledge gaps concerning concentrations, sources, emissions, and spatial trends of mercury (Hg) in the atmosphere in developing regions of the Southern Hemisphere, particularly in urban areas. Filling these gaps is a prerequisite for assessing the effectiveness of international regulation and for enabling a better understanding of the global transport of Hg in the environment. Here we use a passive sampling technique to study the spatial distribution of gaseous elemental Hg (Hg(0), GEM) and assess emission sources in and around Dar es Salaam, Tanzania's largest city. Included in the study were the city's main municipal waste dumpsite and an e-waste processing facility as potential sources of GEM. To complement the GEM data and for a better overview of the Hg contamination status of Dar es Salaam, soil samples were collected from the same locations where passive air samplers were deployed and analysed for total Hg. Overall, GEM concentrations ranged between <0.86 and 5.34 ng m 3 , indicating significant local sources within the urban area. The municipal waste dumpsite and e-waste site had GEM concentrations elevated above the background, at 2.41 and 1.77 ng m 3 , respectively. Hg concentrations in soil in the region (range 0.0067 to 0.098 mg kg 1 ) were low compared to those of other urban areas and were not correlated with atmospheric GEM concentrations. This study demonstrates that GEM is a significant environmental issue in the urban region of Dar es Salaam. Further studies from urban areas in the Global South are needed to better identify sources of GEM.
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    Spatial Trends of Chlorinated Paraffins and Dechloranes in Air and Soil in A Tropical Urban, Suburban, and Rural Environment
    (ELSEVIER, 2021) Nipen, Maja; Vogt, Rolf D.; Bohlin-Nizzetto, Pernilla; Borgå, Katrine; Mwakalapa, Eliezer B.; Borgen, Anders R.; Jørgensen, Susanne J.; Ntapanta, Samwel Moses; Mmochi, Aviti J.; Schlabach, Martin; Breivik, Knut
    There are large knowledge gaps concerning environmental levels and fate of many organic pollutants, particu- larly for chemicals of emerging concern in tropical regions of the Global South. In this study, we investigated the levels of chlorinated paraffins (CPs) and dechloranes in air and soil in rural, suburban, and urban regions in and around Dar es Salaam, Tanzania. Samples were also collected near the city’s main municipal waste dumpsite and an electronic waste (e-waste) handling facility. In passive air samples, short chain CPs (SCCPs) dominated, with an average estimated concentration of 22 ng/m3, while medium chain CPs (MCCPs) had an average estimated concentration of 9 ng/m3. The average estimated air concentration of ∑dechloranes (Dechlorane Plus (DP) + Dechlorane 602 + Dechlorane 603) was three to four orders of magnitudes lower, 2 pg/m3. In soil samples, MCCPs dominated with an average concentration of 640 ng/g dw, followed by SCCPs with an average con- centration of 330 ng/g dw, and ∑dechloranes with an average concentration of 0.9 ng/g dw. In both air and soil, DP was the dominating dechlorane compound. Urban pulses were observed for CPs and dechloranes in air and soil. CPs were in addition found in elevated levels at the municipal waste dumpsite and the e-waste handling facility, while DPs were found in elevated levels at the e-waste handling facility. This suggests that waste handling sites represent important emission sources for these pollutants. Investigations into seasonal trends and environmental fate of CPs and dechloranes showed that monsoonal rain patterns play a major role in governing air concentrations and mobility, particularly for the less volatile MCCPs and dechloranes. This study is the first to report levels of CPs in air from sub-Saharan Africa, and DP, Dechlorane 602, and Dechlorane 603 in soil from sub-Saharan Africa.