| 1. |
- Behbehani, M., et al.
(författare)
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Ocean Acidification-Mediated Food Chain Transfer of Polonium between Primary Producers and Consumers
- 2023
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Ingår i: Toxics. - : MDPI AG. - 2305-6304. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Phytoplankton and zooplankton are key marine components that play an important role in metal distribution through a food web transfer. An increased phytoplankton concentration as a result of ocean acidification and warming are well-established, along with the fact that phytoplankton biomagnify Po-210 by 3-4 orders of magnitude compared to the seawater concentration. This experimental study is carried out to better understand the transfer of polonium between primary producers and consumers. The experimental produced data highlight the complex interaction between the polonium concentration in zooplankton food, i.e. phytoplankton, its excretion via defecated fecal pellets, and its bioaccumulation at ambient seawater pH and a lower pH of 7.7, typical of ocean acidification scenarios in the open ocean. The mass of copepods recovered was 11% less: 7.7 pH compared to 8.2. The effects of copepod species (n = 3), microalgae species (n = 3), pH (n = 2), and time (n = 4) on the polonium activity in the fecal pellets (expressed as % of the total activity introduced through feeding) was tested using an ANOVA 4. With the exception of time (model: F-20,F- 215 = 176.84, p < 0.001; time: F-3 = 1.76, p = 0.16), all tested parameters had an impact on the polonium activity (copepod species: F-2 = 169.15, p < 0.0001; algae species: F-2 = 10.21, p < 0.0001; pH: F-1 = 9.85, p = 0.002) with complex interactions (copepod x algae: F-2 = 19.48, p < 0.0001; copepod x pH: F-2 = 10.54, p < 0.0001; algae x pH: F-2 = 4.87, p = 0.009). The experimental data underpin the hypothesis that metal bioavailability and bioaccumulation will be enhanced in secondary consumers such as crustacean zooplankton due to ocean acidification.
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| 2. |
- Behbehani, M., et al.
(författare)
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Response of corals Acropora pharaonis and Porites lutea to changes in pH and temperature in the Gulf
- 2019
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Ingår i: Sustainability (Switzerland). - : MDPI AG. - 2071-1050. ; 11:11
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Tidskriftsartikel (refereegranskat)abstract
- Coral reefs are harboring a large part of the marine biodiversity and are important ecosystems for the equilibrium of the oceans. As a consequence of anthropogenic CO2 emission, a drop in pH and an increase in seawater temperature is observed in the Gulf coastal waters that potentially threaten coral assemblages. An experimental study was conducted on two species of corals to assess the effect of ocean warming and ocean acidification on the net calcification rate. Two pH conditions 8.2 and 7.5 and three temperatures, 22.5, 27.5 and 32.5 °C, were considered. Net calcification rates were measured using 45Ca radiotracer. Both temperature and pH had a significant effect on net calcification rates following a similar pattern for both species. The highest calcification rate was observed at low temperature and high pH. Increased temperature and decreased pH led to a decrease in net calcification rates. An interactive effect was observed as the effect of pH decreased with increasing temperature. However, the two species of coral were able to calcify in all the tested combination of temperature and pH suggesting that they are adapted to short term changes in temperature and pH. Ability to calcify even at a high temperature of 32.5 °C that is identical to the summertime Gulf seawater temperature under both the ambient and low pH condition with no mortalities, raises a question: are these corals adapted to high seawater temperatures and low pH? More in-depth assessments will be required to confirm if this is an adaptation to higher temperatures in Persian Gulf corals. © 2019 by the authors.
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| 3. |
- Uddin, S., et al.
(författare)
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A Preliminary Assessment of Size-Fractionated Microplastics in Indoor Aerosol—Kuwait’s Baseline
- 2022
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Ingår i: Toxics. - : MDPI AG. - 2305-6304. ; 10:2
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Tidskriftsartikel (refereegranskat)abstract
- The omnipresence of microplastic (MP) in various environmental samples, including aer-osols, has raised public health concerns; however, there is presently very limited information on MPs in indoor aerosol. This paper presents a unique dataset where smaller MPs have been sampled using a six-stage cascade impactor from indoor environments in Kuwait. The MP concentration in the indoor air varied between 3.2 and 27.1 particles m−3, and the relative MP concentration decreased linearly from the lowest to the highest size fraction. A significant effect of location was observed for the total number of MPs (F2,14 = 5.80, p = 0.02) and the inhalable fraction (F2,14 = 8.38, p = 0.005), while location had no effect on the respirable fraction (F2,14 = 0.54, p = 0.60). A significant effect of the type of air conditioning used was also observed for the total number of MPs (F2,19 = 5.58, p = 0.01) and the inhalable fraction (F2,19 = 6.45, p = 0.008), while location had no effect on the respirable fraction (F2,19 = 1.30, p = 0.30). For the total number of MPs and the inhalable fraction, the concentration was sig-nificantly higher for the split unit air-conditioning as compared to the central air-conditioning plants. The presence/absence of carpets had no significant effect on the MP concentrations (total: F1,19 = 4.08, p = 0.06; inhalable: F1,19 = 3.03, p = 0.10; respirable: F1,19 = 4.27, p = 0.05). The shape was dominantly fibers, with few fragments in lower size fractions. These datasets represent the first baseline information for Kuwait, and the smaller MPs in all the samples further underscore the need to develop standardized protocols of MP collection in the ≤2.5 µm fraction that can have more con-spicuous health implications. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.
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| 4. |
- Uddin, S., et al.
(författare)
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Assessment of loss of Po-210 from fish and shrimp by cooking and its effect on dose estimates to humans ingesting seafood
- 2019
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Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X. ; 205, s. 1-6
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Tidskriftsartikel (refereegranskat)abstract
- An experimental study was conducted to assess loss of Po-210 due to cooking fresh seafood, and provide a more realistic and reliable dose estimate that humans may receive from consuming cooked seafood. Fresh fish and shrimp samples from Northern Gulf waters were grilled and boiled to simulate the effect of different cooking methods. Sixteen different species of fish were compared and significant differences in Po-210 concentration in uncooked samples were observed between species (ANOVA I, F-15,F-79 = 362.81, p < 0.0001). The effect of the treatment (uncooked, grilled, boiled and stock) was compared for each species and it was found that cooking led to a significant decrease in Po-210 concentration ranging from 14 to 58% compared to the uncooked samples, with no difference between grilled or boiled treatments. The effect of the cooking and shrimp treatment on Po-210 concentration was tested using ANOVA II after logarithmic transformation. Cooking led to a significant 38% reduction of Po-210 concentration as compared to uncooked treatments with no difference between grilled and boiled samples (ANOVA I: F-3,F-99 = 14.72, p < 0.0001). The two treatments with deveined shrimp led to a 75% decrease in Po-210 concentration as compared to all other treatments. As a consequence, cooked deveined shrimp contained an 84% lower Po-210 concentration than whole uncooked shrimp. As Po-210 is known to be the major contributor to radiation dose in humans consuming seafood, based on the results obtained, it is evident there is a need to re-examine how committed effective doses (CEDs) are best calculated for seafood consuming populations considering that most populations consume fish and shellfish cooked.
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