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The paper presents the systematic investigations on the activity concentrations of 210Po and 210Pb in the riverine environs of Bharathapuzha, Periyar and Kallada, the three major rivers of coastal Kerala. The radionuclides 210Po and 210Pb in sediment and water samples were separated using radiochemical methods and activity was counted using scintil...
Citations
... Kemp et al., 2017, Chen andTorres (2018) and Bera et al., (2018) similarly reported that 210Po is usually adsorbed on clay and differential movement of fine particles could alter its profiles during the decomposition of the organic phases. Furthermore, both Tudor and Mtwapa creeks receive large amounts of untreated wastewater from industrial and domestic sources as reported by Okuku et al., (2011), which could be contributing significantly to the sediment organic matter as reported elsewhere by Saçan et al., (2010) and Venunathan and Narayana (2016). ...
Water, sediment and biota samples were collected from selected locations along the Kenyan Coast. The nutrient levels in surface water were relatively elevated as a result of sewage and riverine inputs. As, Cd, Pb, Hg and Ag levels in sediment from Kilindini Harbor pose minimal threat to marine life whereas Cu, Zn and Ni in the sediment pose a moderate threat to marine life while Cr levels in the sediment may have a severe impact on marine life. The concentrations of trace metals, PCBs, and DDT in the surface sediment were lower than the ERL thus posing a low threat to marine organisms. DDD+DDE/DDT ratios were above 0.5 suggesting historical input of DDT from rivers Tana, Sabaki and Ramisi. Trace metal concentrations in biota from Mtwapa, Makupa and Tudor creeks were below the WHO permissible levels of heavy metals in fish. The study concludes that sound management of marine environment is crucial for promoting fisheries as one of the sectors of the Blue Economy.
... The correlation between 210 Po and 210 Pb activities was significantly good as it is shown in Fig. 4. This means that as has been observed in the case of some natural environments such as surface waters, also in the case of honey the presence of the one radionuclide can be a good indicator of the other something which could be attributed to their similar chemical properties (Venunathan, & Narayana, 2016). As regards honey and foodstuffs, that would be valuable information since the radionuclides are tested as food contaminants. ...
Greek honey was examined for 238U, 234U, 210Pb, 210Po, 40K, and 137Cs levels. 238U was calculated from 0.013 ± 0.007 Bq kg−1 to 0.10 ± 0.02 Bq kg−1 while 234U ranged from 0.017 ± 0.009 Bq kg−1 to 0.11 ± 0.03 Bq kg−1. 210Pb measured from 0.04 ± 0.02 Bq kg−1 to 1.70 ± 0.26 Bq kg−1 whereas 210Po activity determined between 0.02 ± 0.01 Bq kg−1 and 2.31 ± 0.34 Bq kg−1. 40 K found at the range of 7.9 ± 1.6 Bq kg−1 to 102.2 ± 19.7 Bq kg−1 and 137Cs 0.3 ± 0.1 Bq kg−1 up to 0.8 ± 0.1 Bq kg−1. Uranium isotopes and 210Po were determined via alpha spectrometry. 210Pb was also indirectly determined by alpha spectrometry. 40 K and 137Cs were measured through γ-ray spectrometry. An annual dose calculation was performed for different age groups.
... ng/g dw) compared to Sabaki (2.34 ng/g dw) and Ramisi (0.23 ng/g dw). This suggests that even though DDT was banned in Kenya in 1986, there could still be illegal use of DDT in Kenya [56]. ...
Marine contamination arising from land-based sources is on the rise along the Kenyan Coast. We carried out a decadal pollution survey between 2008 and 2018 to determine the levels of various pollutants (nutrients, trace metals, persistent organic pollutants, and 210 Po) in water, sediment, and biota collected from selected locations in Kenya. Nutrient levels in water ranged between <0.10 and 1560.00, <0.10 and 1320.00, and <0.10 and 3280.00 μg/L for PO 4 3−-P, (NO 2 − + NO 3 −)-N, and NH 4 +-N, respectively, while Chl-a values ranged between 0.02 and 119.37 mg/L. Total PAH, PCBs, and OCPs in sediment from the studied locations ranged from BDL-37800, 0.012-7.99 and BDL-6.10 ng/g. High level of PAH in Kilindini port was primarily from petroleum sources. DDD + DDE/DDT ratio was above 0.5 suggesting historical input. Sediment trace metal concentration from selected locations in Kenyan estuaries had various ranges, that is, Al (0.06-9804284.00 μg/g), Zn (3.82-367.20 μg/g), Cu (7.5-169.60), Cd (DL −2.40 μg/g), Mn (BDL-169.60 μg/g), Cr (2.55-239.10 μg/g), and Pb (BDL-135.60) μg/g dw. Surface sediment 210 Po activities ranged between 20.29 and 43.44 Bq kg −1 dw. Chl-a and PO 4 3−-P data revealed enhance primary productivity in Mombasa peri-urban creeks and estuarine areas. Although the reported concentrations of trace metals and POPs are low in most locations from Kenya, there is a potential risk of bioaccumulation of these contaminants in marine biota; thus, there is a need for continuous monitoring to protect both ecosystem and human health.
... 210 Pb is found in surface soil as supported fraction (formed within the soil surface due to radioactive decay of 238 U via 222 Rn) and unsupported fraction (formed due to radioactive decay of 222 Rn exhaled from soil into atmosphere and deposited back to surface soil) and further decays into 210 Po (via 210 Bi). Higher activity of 210 Pb as compared to 210 Po in the surface soil indicates some contribution from unsupported fraction [57,58]. As discussed, due to the U mineralization, soils in the study area are anticipated to have significantly higher degree of 222 Rn exhalation resulting in higher 210 Pb inventory in surface soil by means of dry and wet deposition of unsupported fraction thereafter. ...
Present study evaluates distribution of 210Pb and 210Po in soil around uranium mineralized region of East Singhbhum district, Jharkhand, India. The overall median activity concentration of 210Pb and 210Po in soil was observed to be 95 ± 35 Bq kg−1 and 79 ± 35 Bq kg−1, respectively. Based on KS test, both the radionuclides follow normal distribution in the study area. The extent of disequilibrium in soil is evaluated using 210Po/210Pb activity ratio. Also, comparison between cultivated and virgin (uncultivated) lands based on activity concentration of 210Pb and 210Po and 210Po/210Pb activity ratio has been carried out. Higher median activity concentration of both the radionuclides were observed in cultivated soil compared to uncultivated soil. Comparison of 210Po/210Pb ratio indicates higher degree of radioactive disequilibrium in cultivated soils (210Po/210Pb = 0.70) compared to uncultivated soils (210Po/210Pb = 0.99). Further, correlation study indicated significant difference between cultivated and uncultivated soils with respect to 210Po and 210Pb. The observed difference between cultivated and uncultivated soil could be due to physical and chemical alterations of cultivated land during farming practices.
... Since then, almost all oceanographic or limnologic studies that address recent depositional processes have employed 210 Pb as one of the powerful geochronometers (Andrews et al., 2009;Baskaran and Swarzenski, 2007;Gale, 2009;Persson and Holm, 2011;Rink and Thompson, 2016). For example, it has been widely used to study the dynamics of sedimentary processes (Appleby, 2001;Arias-Ortiz et al., 2018;Delbono et al., 2016;Edelman-Furstenberg et al., 2020;Liu et al., 2020;Mahmood et al., 2011;Ruiz-Fernández et al., 2016;Sanchez-Cabeza and Ruiz-Fernández, 2012;Sun et al., 2020;Venunathan and Narayana, 2016), historical trends of hypoxia (Li et al., 2011) and eutrophication (Zimmerman and Canuel, 2002), and the history of marine pollution in coastal regions Díaz-Asencio et al., 2011;Heim and Schwarzbauer, 2013;Heim et al., 2004;Kim et al., 2007;Mitra et al., 1999;Neves et al., 2018;Schwing et al., 2017;Sun et al., 2020;Taieb Errahmani et al., 2020;Venkatesan et al., 1999;Yunuén et al., 2011). 210 Pb has also been successfully used to estimate sediment accumulation rates in ultradeep hadal trenches Luo et al., 2019;Wenzhöfer et al., 2016) (Fig. 2). ...
... There are many other dating methods for marine sediments, such as excess 231 Pa (Hillaire-Marcel et al., 2017;Lao et al., 1992), 210 Po (Pandit et al., 2014;Persson and Holm, 2011;Venunathan and Narayana, 2016), and amino acid racemization dating (Bada et al., 1970;Demarchi et al., 2011;Hearty et al., 2004;Kaufman et al., 2008;West et al., 2019) etc. As these have yet to be widely applied in paleoceanography, this paper will not discuss them in detail (Fig. 2). ...
Microplastic (<5mm) accumulation in water environments is an emerging concern issue, it can be absorbed throughout the food chain. Filter organisms are the most susceptible, so they have the potential to be an environmental sentinel. Thus, tests were carried out with three mussels species in order to investigate the filtration and prevalence of microplastic in them. The investigated bivalves have shown different forms of microplastics in soft tissues, feces and pseudofeces. However, the identification of polymer blends is still tricky. This outcome has indicated the potential of these bivalves to be used as bioindicators associated with this contaminant in environments.
... N=27, p=0.023). Our findings showed 210 similar trend with Venunathan et al., (2016) where Pb increase was in proportion to organic matter in sediments. ...
... N=27, p=0.023). Our findings showed 210 similar trend with Venunathan et al., (2016) where Pb increase was in proportion to organic matter in sediments. ...
Aim: To investigate the effect of dissolved oxygen deficiency on the level of 210Pb in mussel's tissues, Perna viridis which has been reported to be highly tolerant to hypoxia. Methodology: Mussels (Perna viridis), seawater and sediment samples were collected from nine stations along the Johor Straits during North-east monsoon (November 2017), inter-monsoon (March 2018), and South-west monsoon (August 2018). The 210Pb contents were extracted and estimated by Gross Alpha-beta Counter. Results: The lowest dissolved oxygen was recorded at Station 4 which decreased from 2.14 mg l-1 to 2.10 mg l-1 and subsequently to 1.63 mg l-1 during first to third samplings. In sediment, 210Pb activities increased with the increase in organic matter. Meanwhile, in mussels, the 210Pb activities showed almost similar trend with sediment where 210Pb activities were much higher adjacent to the causeway structure, especially at the East part of Johor Strait. The level of 210Pb in mussel's tissue and sediment also increased with decreasing level of dissolved oxygen. Interpretation: A causeway structure disrupted the water quality of Johor Straits and caused almost hypoxic conditions nearby. The coverage of oxygen depletion expanded during inter-monsoon. An inverse relationship between 210Pb activities and dissolved oxygen prove that deficiency of dissolved oxygen potentially influenced the bioaccumulation of 210Pb in mussels to correspond to the build-up of concentration factor in their tissues which exceeded the recommended value.
... Since then, almost all oceanographic or limnologic studies that address recent depositional processes have employed 210 Pb as one of the powerful geochronometers (Andrews et al., 2009;Baskaran and Swarzenski, 2007;Gale, 2009;Persson and Holm, 2011;Rink and Thompson, 2016). For example, it has been widely used to study the dynamics of sedimentary processes (Appleby, 2001;Arias-Ortiz et al., 2018;Delbono et al., 2016;Edelman-Furstenberg et al., 2020;Liu et al., 2020;Mahmood et al., 2011;Ruiz-Fernández et al., 2016;Sanchez-Cabeza and Ruiz-Fernández, 2012;Sun et al., 2020;Venunathan and Narayana, 2016), historical trends of hypoxia (Li et al., 2011) and eutrophication (Zimmerman and Canuel, 2002), and the history of marine pollution in coastal regions Díaz-Asencio et al., 2011;Heim and Schwarzbauer, 2013;Heim et al., 2004;Kim et al., 2007;Mitra et al., 1999;Neves et al., 2018;Schwing et al., 2017;Sun et al., 2020;Taieb Errahmani et al., 2020;Venkatesan et al., 1999;Yunuén et al., 2011). 210 Pb has also been successfully used to estimate sediment accumulation rates in ultradeep hadal trenches Luo et al., 2019;Wenzhöfer et al., 2016) (Fig. 2). ...
... There are many other dating methods for marine sediments, such as excess 231 Pa (Hillaire-Marcel et al., 2017;Lao et al., 1992), 210 Po (Pandit et al., 2014;Persson and Holm, 2011;Venunathan and Narayana, 2016), and amino acid racemization dating (Bada et al., 1970;Demarchi et al., 2011;Hearty et al., 2004;Kaufman et al., 2008;West et al., 2019) etc. As these have yet to be widely applied in paleoceanography, this paper will not discuss them in detail (Fig. 2). ...
Dating methodologies for Quaternary marine sediments play increasingly important roles in the reconstruction
of paleoenvironments and paleoclimate in (paleo)oceanography. Previous reviews or studies have focused
mainly on one or two methodologies, and their applications in one specific environment. With the continuing
technological and methodological advances in different methods over the past few decades, an up-to-date comparison
of the pros and cons of each dating methodology is needed to clearly understand their applications inmarine
geoscience research. In this review,we first briefly summarized the common methods of absolute dating and
relative dating. These are (1) radioisotope dating with different half-lives using natural nuclides of 234Th, 210Pb,
230Th, and 226Ra, cosmogenic nuclides of 7Be, 14C, 10Be, 32Si, 26Al, 36Cl and 21Ne, and the artificial radionuclides
of 137Cs, 239, 240Pu, 241Am and 129I that have been induced by atmospheric nuclear tests, accidents in nuclear
plants, and discharges of radioactive wastes; (2) radiation exposure dating of luminescence and electron paramagnetic
resonance (ESR) dating; and (3) stratigraphic dating of δ18O and paleomagnetic sequence. Applications
and limitations fromthemarine terraces, estuaries, to hadal trenches have been summarized to each technique in
the study of Quaternary marine geoscience extending from the Anthropocene through the Pleistocene. Finally,
we introduced some emerging event dating methods, namely the arrivals of microplastics, mercury isotopes,
and organic pollutant deposition that all appeared after the industrial resolution in our now changing oceaninfluenced by acidification, global warming, and anthropogenic activities. We ended by discussing future perspectives
for reliable and high-resolution chronology by interdisciplinarymethods including computer programming
to better understand the natural geological evolution and predict the future changes in earth science.
... Andrew et al. (2017), Chen and Torres (2018) and Gopal et al. (2018) similarly reported that 210 Po (among other radionuclides) is usually primarily adsorbed on clay and differential movement of fine particles could alter its profiles during the decomposition of the organic phases. Furthermore, both Tudor and Mtwapa creeks receive large amounts of untreated wastewater from industrial, agricultural and domestic sources as reported by Okuku et al. (2011), which could be contributing significantly to the sediment organic matter as reported in studies by Saçan et al. (2010) and Venunathan and Narayan (2016). ...
... In addition, high levels of silt and organic matter (Table 1) were found in Mtwapa creek sediment, which may have also contributed to the observed high levels of 210 Po activity. This is in agreement with the work by Fernandes et al. (2011) and Venunathan and Narayan (2016) who reported that sediment rich in organic matter and silt content tend to have higher 210 Po activities. ...
... Previous studies have used natural radionuclides for determining the accumulation rates and chronologies of sediment deposition in coastal areas. Due to its half-life of about 22.3 years, 210 Pb has proved to be an important nuclide for studying coastal sedimentary processes (Appleby, 2001;Mahmood et al., 2011;Sanchez-Cabeza and Ruiz-Fern� andez, 2012;Venunathan and Narayana, 2016;Delbono et al., 2016). Since 210 Pb has a short residence time in the atmosphere, it is quickly sequestered in sediments and, over just a few months, it becomes permanently fixed onto sediment particles (Tee et al., 2003). ...
