环境•农林最新文献

Emamectin benzoate based insecticide and glyphosate based herbicides are widely used in developing countries for agricultural purposes. The problem lies in the total lack of knowledge of data on their uses as well as the absence of scientific data on the potential effects on local biodiversity. This study evaluates the acute and chronic effects of two commercial formulations EMACOT^® and SUNPHOSATE-G^® on juveniles of a prawn species (Macrobrachium macrobrachion) native of large watersheds in Benin. Juveniles with an average weight of 1.49 ± 0.2 g were subjected to six and seven lethal doses of EMACOT^® and SUNPHOSAT-G^® respectively. Thus, swimming behavior, loss of mobility and mortality were monitored every hour for 72 h. Then, sub-lethal effects on molting effectiveness, weight and size gain as well as survival were evaluated on juveniles individually exposed to nominal concentrations of 0.06 and 0.11 mg.L^-1 of EMACOT, and 13.99 and 27.98 mg.L^-1 of SUNPHOSATHE-G. The results showed that the LC₅₀-72 h of the herbicide formulation on juveniles is 279.76 mg.L^-1 which corresponds to 211.78 mg.L^-1 of glyphosate. That of the insecticide is 1.14 mg.L^-1 corresponding to 0.06 mg.L^-1of emamectin benzoate. As for the chronic effects, both concentrations of emamectin benzoate prevented the prawn from molting (1 molt at the start of the experiment against 3 molts for the control subjects in 28 days). As a result, weight gain in these two treatments was very low (0.06 and 0.19 g, respectively) compared to 0.66 g in the controls. For glyphosate, findings with 13.99 mg.L^-1 are similar to those of both doses of emamecin benzoate. On the other hand, no significant effect was observed on the effectiveness of molts within 27.98 mg.L^-1 treatment (3 molts in 28 days). The weight gain was 0.11 g and 0.46 g respectively for both glyphosate sub-lethal doses. The results of this study indicate a significant sensitivity of the prawn juveniles to emamectin benzoate (EMACOT) and a relatively low sensitivity to glyphosate (SUNPHOSATE-G). But the risk is significant when these two pesticides are used in the flood plains of large rivers. In developing countries such as Benin, measures must be taken to review current pesticide use practices in large watersheds.

Acroceridae are active parasitoids of mygalomorph spiders. However, little is known of their interaction numbers and biology in the Neotropics. In this study, we present 15 new records of acrocerid–mygalomorph interactions, adding new biological information about spider fly development. Mygalomorph spiders were captured in the field and maintained in captivity, and the development time of acrocerids was followed from the 4th instar to adulthood. Only seven acrocerid flies were able to complete their development. The acrocerids obtained were Arrhynchus stuardoi, Arrhynchus maculatus, and Archipialea sp. The total recorded development time (from the point where the larva leaves its host to the eclosion of the adult fly) of the spider flies was between 20 and 29 days. The collaboration of citizen scientists could be a useful alternative in the future to fill gaps in the biological and ecological information about these parasitoid flies.

Desalination is the most promising technology to resolve present water scarcity issues and improvement is required to increase its productivity and various other drawbacks including lower water flux, membrane fouling, and high-energy requirements. Currently available desalination membranes exhibits a water flux of 18–34 L/m².h. Modification of the existing membranes can enhance its performance and thereby makes it efficient for desalination. In this investigation, introduction of Polyvinyl pyrrolidone was aimed to enhance the permeability of the Polysulfone membrane, given that the membrane’s water flux is predominantly influenced by its porosity. Further modification of the membrane was done by adding functionalized multi-walled carbon nanotubes onto the polyamide layer over the polysulfone membrane to improve the salt removal efficiency. The fabricated membranes were characterized by its swelling, porosity, water uptake, surface roughness, contact angle, morphology and surface chemistry. The performance of the fabricated membrane for desalination was evaluated using a cross flow filtration experimental setup. The characterization studies confirmed the modification of hydrophobic polysulphone membrane to hydrophilic by the addition of functionalised multi-walled carbon nanotubes (MWCNTs). The findings demonstrated that the membrane with 0.01% w/v of MWCNTs exhibited enhanced water flux at 42 L/m².h with a salt rejection of 92%. The performance of the used membrane was retained by conducting regeneration study using acid cleaning. This study will be helpful for water managers to come out with a better method to fabricate membranes for desalination.

The global postdoctoral community faces many challenges including low pay, irregular benefits, little job security amid cost-of-living hikes, challenges to mental health, and power imbalances. Conclusions from the 2020 and 2023 global postdoctoral surveys by Nature highlighting these struggles are highly skewed towards respondents from the Global North, underrepresenting the Global South. Here, we address the postdoctoral struggles of scholars in the Global South who are more vulnerable due to low-income economy and patriarchal society that discriminates against women. We argue that neglecting postdoctoral researchers in basic science fields, women and scholars from local and regional universities will affect global academic and research outputs. We recommend sustainable, long-term solutions such as “Postdoc Representative Body” ensuring just and wider postdoctoral benefits at country level to secure postdoctoral benefits in the Global South.

In the present study, radon concentrations were measured in soil samples collected from different sites in Kadhimiya district center in Baghdad, Iraq. A CR-39 passive nuclear track detectors was used to assess the radon concentrations through the sealed can technique. This study include an assessment of various radiation hazard parameters in 25 soil samples, including the annual effective dose, excess lifetime cancer risk, radium activity, uranium concentration, as well as surface and mass exhalation rates. The mean values were found to be 282.29 ± 3.83 Bq m⁻³ for radon concentration, 7.12 ± 0.096 mSv y⁻¹ for annual effective dose, 24.93 for excess lifetime cancer risk, 0.39 ± 0.002 Bq kg⁻¹ for radium activity, 135.75 ± 1.84 mBq m⁻²h⁻¹ for surface exhalation rate, 3.14 ± 0.04 mBq kg⁻¹h⁻¹ for mass exhalation rate, and 5.91 ± 0.079 PPb for uranium concentration. Consequently, the mean radon concentration exceeded the suggested limits, typically ranging between 200 and 600 Bq m⁻³, and the annual effective dose exceeded the recommended threshold of 1 mSv y⁻¹. However, the radium content was below the recommended limit of 30 Bq kg⁻¹. A significant direct correlation was observed between the radium concentration and both the surface and mass exhalation rates. It is recommended to expand this study to measure radon and thoron gas concentrations within buildings of the study area to enhance the understanding of indoor exposure risks. Additionally, it would be beneficial to estimate the concentrations of other radionuclides, such as ²³²Th and ⁴⁰K, as well as the major cations and anions in the soil to elucidate their potential impact on radon levels. Further actions to control radon exposure in the community to prevent lung cancer is important.