November 2024
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Population and Development Review
Theories of contraception and fertility are currently dominated by economic and cultural arguments. A demographic perspective can usefully expand these theories through "addition," "explication," and "reconciliation." The addition is about drawing attention to salient demographic forces that have previously been undercon-sidered whether these forces operate at the macro, meso, or microlevels. Explication is about adding explanatory flesh to proximate economic or cultural influences, which can themselves result from more fundamental demographic changes. Finally, reconciliation is about moving beyond an "economy-OR-culture" binary to seek comple-mentarities and synergies. Decomposition methods inspired by a demographic perspective help such reconciliation. They offer handy empirical tools for assessing how economic, cultural, and demographic forces jointly shape changes in national rates of contraception, and how their contributions may change over time. Thus, demographic perspectives are not offered as a substitute but as an avenue to integrate cultural, economic , and demographic perspectives and to foster richer contextual analysis.
![Figure 2. Histogram of heavy metal concentrations in soils samples Chromium (Cr): Chromium concentrations in the soil samples analysed ranged from 2.8 mg/kg to 93.5 mg/kg, with an average of 42.1 mg/kg (Table 4). The highest concentration was obtained in sample F5 and the lowest in sample F11 (Figure 2). The average Cr concentration of this study (42.1 mg/kg) was higher than the upper continental crust (UCC) value set at 35 mg/kg according to Wedepohl (1995) [30]. The guide values set by the FAO/WHO, French legislation (NF U44 04410) and South Africa are respectively 100 mg/kg [60] ,150 mg/kg [22,61] and 46 mg/kg [62]. All samples had Cr concentration below these guide values. Analysis of the samples shows that only two samples had levels above the level of 70 mg/kg which is the normal value for uncontaminated soils [63]. Cr concentrations higher or lower than the average of this study have been reported by other researchers. In Malaysia, the highest average Cr concentration obtained by Diami et al. (2016) [64] in surface soils associated with iron ore mining was 11.07 mg/kg. In the same year, Olobatoke et al. (2016) [65] measured in the soils and in the tailings pond near a former gold mine in South Africa, an average concentration of 173.39 mg/kg. In China, Pan et al. (2023) [66] measured an average Cr concentration of 54.58 mg/kg in soils from a lead-zinc mining watershed. Nickel (Ni): The average value of the nickel concentration in the soils samples from Bouly was 11.4 mg/kg. It was lower than the continental crust average set at 16.8 mg/kg according to Wedepohl (1995) [30], as well as the standards established by FAO/WHO, South Africa and France (NF-U4404411). The Ni concentrations in the samples varied between 6.8 mg/kg (sample F8) and 16.1 mg/kg (sample F12). All these values were below the normal value for uncontaminated soils set at 50 mg/kg by Bowen in 1979 [63], which suggests that the soils in the sampling area were not contaminated with Ni. These concentrations were also lower than the result of Wang et al. (2021) [67], who obtained an average value of 48 mg/kg. In soils around the Kapan mining area in Armenia, Gevorgyan et al in (2017) [68] obtained an average concentration of 67.35 mg/kg. Copper (Cu): The average value of copper in the studies samples was 33.9 mg/kg. This value was higher than the UCC value (14.3 mg/kg according to [30]) and the South African standard (16 mg/kg according [62]). However, this average remains significantly lower than the regulatory value of 100 mg/kg defined by the French](https://www.researchgate.net/profile/Inoussa-Zongo/publication/375991509/figure/fig2/AS:11431281207485101@1701204961270/Histogram-of-heavy-metal-concentrations-in-soils-samples-Chromium-Cr-Chromium_Q320.jpg)
