Toxicokinetics of cadmium in Palaemon varians postlarvae under waterborne and/or dietary exposure

Abstract

The present study assessed cadmium uptake and depuration rates in the euryhaline estuarine shrimp Palaemon varians under different exposure routes. Postlarval shrimp were exposed for four days under different exposure routes; through contaminated water, contaminated diet and a two-way exposure scenario where both contaminated water + diet were used. After exposure, postlarval shrimp were transferred to a clean medium and fed a non-contaminated diet for 96 h. Bioaccumulation via the different exposure routes was modeled with a standard first-order one-compartment toxicokinetics model and one with an additional parameter reflecting an inert fraction or storage compartment. The simultaneous two-way exposure (through water and diet) resulted in accumulation being almost twice as high as the sum of the individual exposure routes, thus indicating that accumulation from multiple routes may be more than additive. Cadmium uptake from water was faster than uptake from food maintained for 48 h at that same cadmium concentration. Shrimp were unable to eliminate cadmium from their body, showing no depuration during 96 h after exposure via different routes, thus suggesting that a longer depuration period is needed. Model comparisons did not provide a significantly better fit when the model included the presence of an inert fraction. The present study highlights the importance of assessing accumulation using multiple exposure routes compared to individual ones, as the latter may underestimate bioaccumulation. This article is protected by copyright. All rights reserved

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IJERPH, Vol. 15, Pages 246: Spatio-Temporal Dynamic Analysis of Sustainable Development in China Based on the Footprint Family

IJERPH, Vol. 15, Pages 246: Spatio-Temporal Dynamic Analysis of Sustainable Development in China Based on the Footprint Family

International Journal of Environmental Research and Public Health doi: 10.3390/ijerph15020246

Authors: Jing Zhao Caihong Ma Xiangui Zhao Xiaoyu Wang

The existing index systems on sustainable evaluation are mostly based on a multi index comprehensive evaluation method. The main disadvantage of this approach is that the selection and assignment of evaluation indexes are greatly influenced by subjective factors, which can result in poor comparability of results. By contrast, the Footprint Family (including ecological footprint, carbon footprint, and water footprint) is not affected by subjective factors. The Footprint Family also covers the basic tenets of sustainable development. This paper proposes use of a sustainable development evaluation index system based on the principle of the Footprint Family, and including the ecological pressure index (EPI), the ecological occupancy index (EOI), the ecological economic coordination index (EECI), the GHG (Greenhouse Gas) emission index (CEI), the water resources stress index (WSI), and the sustainable development index (SDI). Furthermore, a standard for grading the evaluated results based on global benchmarks is formulated. The results of an empirical study in China were the following. The development situation deteriorated from 1990 to 2015. The results showed that the SDI decreased from a medium level (grade 5) to a lower-medium level (grade 4). The results of this empirical study also showed that the method of evaluation can avoid the influence of subjective factors and can be used in the evaluation of sustainable development for various temporal and spatial conditions.

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The impact of pesticides on the macroinvertebrate community in the water channels of the Río Negro and Neuquén Valley, North Patagonia (Argentina)

Abstract

Agriculture represents the second most important economic activity in the North Patagonian Region of Argentina and non-selective insecticides are still being used with significant implications to the quality of the environment. The range of concentrations (μg/L) determined for azinphosmethyl, chlorpyrifos, and carbaryl in drainage channels were from non-detected to 1.02, 1.45, and 11.21, respectively. Macroinvertebrate abundance and taxon richness in drainage channels were significantly lower in November compared to the other sampling months (October, February). The decrease in taxon richness observed in November was associated with chlorpyrifos and azinphosmethyl peak concentrations. The most remarkable changes were the decrease in sensitive taxa such as Baetidae and the increase in some tolerant taxa such as Chironomidae and Gastropoda.

For all three pesticides, the acute hazard quotient exceeded the risk criteria for invertebrates. The effects of the three pesticides on aquatic organisms, characterized by joint probability curves, showed that the LC₅₀ of 10% of the species were exceeded five and three times by the concentrations of azinphosmethyl and chlorpyrifos during the study period, respectively. However, the correlation between the pesticide concentrations and both taxon richness and abundance of macroinvertebrates at each site (irrigation and drainage channels) was indicative that only chlorpyrifos was negatively correlated with both parameters (Spearman r² − 0.61, p = 0.0051 and Spearman r² − 0.59, p = 0.0068 for taxon richness and abundance correlation, respectively). We conclude that macroinvertebrate assemblages in drainage channels were highly affected by chlorpyrifos levels.

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Effects of cadmium on photosynthesis of Schima superba young plant detected by chlorophyll fluorescence

Abstract

Contamination by heavy metals has become a serious environmental pollution issue today due to its potential threat to plant, wildlife, and human health. Photosynthesis, a process in which light energy is used to produce sugar and other organic compounds, is sensitive to heavy metals. In the present study, the response of photosynthetic process and carbon assimilation of Schima superba was investigated under cadmium (Cd) stress. Three Cd concentrations (0, 300, and 600 mg kg⁻¹) were used designated as control (CK), low Cd (L₁), and high Cd treatment (L₂) of plants. Results showed that photosystem II (PSII) acceptor and donor side electron transport were more easily blocked in treatment compared to control, and L₂ have more significant changes than L₁. A substantial decrease of 820 nm reflection curve absorption was observed both in L₁ and L₂ treatments. Special energy fluxes showed significant difference between the control group and the treated group, which indicated that low concentration Cd stress can cause decrease in quantum yield of PSII in plants studied. Non-stomatal factors resulted in a decrease in net photosynthetic rate and a decrease in photosystem activity. Our results suggested that Cd can damage structure and function of the photosynthesis of S. superba young plants.

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Analysis and utilization of temple waste flowers in Coimbatore District

Abstract

The present work deals with collection, handling, utilization, and management of the waste flowers that are coming out of the temples in Coimbatore District, Tamilnadu, India. An attempt has been made to provide a current situation and complete analysis of temple waste flowers (TWFs) with suggestions and recommendations. As a part of Clean India, Clean and Green Kovai (Green Coimbatore) mission, this paper gives an idea to reduce the volume of temple waste flowers by converting into activated carbon by direct pyrolysis process and chemical activation with sulfuric acid and phosphoric acid process, respectively. The products were analyzed and compared based on the results of physicochemical parameters including pH, conductivity, moisture content, ash content, volatile content, fixed carbon, bulk density, porosity, specific gravity, water soluble matter, acid soluble matter, iodine number, methylene blue number, yield, and Brunauer-Emmett-Teller (S_BET) surface area. The structure, surface morphology, and chemical compositions of carbon were determined by field emission scanning electron microscopy (FeSEM), and energy-dispersive X-ray spectroscopy (EDS), respectively. From the comparison of results, the activated carbon produced from temple waste flowers by direct pyrolysis process is fairly better due to low moisture content, low ash content, better yield, and higher surface area.

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IJERPH, Vol. 15, Pages 245: Empowering Retailers to Refuse to Sell Tobacco Products to Minors

IJERPH, Vol. 15, Pages 245: Empowering Retailers to Refuse to Sell Tobacco Products to Minors

International Journal of Environmental Research and Public Health doi: 10.3390/ijerph15020245

Authors: Min-Li Chen Li-Na Chou Ya-Cheng Zheng

Tobacco smoking and exposure to secondhand smoke are major environmental risk factors that negatively influence health. It is recommended that tobacco product manufacturers and retailers receive empowerment counseling programs to achieve adolescent health targets. The present study conducted an empowerment counseling session to counsel tobacco product retailers in refusing to sell tobacco products to minors. The three stages of this study were conducted from March 2015 to February 2017. The results revealed that 74% of retailers were selling tobacco products to minors at baseline, 40% at stage two and 15% at stage three. These represent significant reductions in selling tobacco products to minors (all stage differences p < 0.001). However, experimental design studies could be used to examine the empowerment counseling program for preventing tobacco sales to minors in the future. Moreover, health care providers should collaborate with tobacco product retailers to design unique empowerment counseling sessions for specific regions to improve retailers' capabilities for self-management in terms of tobacco hazard prevention.

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Influence of labile dissolved organic matter on nitrate reduction in a seepage face

Abstract

Seepage faces, the outer rim of subterranean estuaries, are an important reaction node for SGD-borne nitrate (NO₃⁻) on a global scale. Labile dissolved organic matter (DOM) has been suggested to be a key factor constraining the NO₃⁻ removal rate in aquifer systems. To determine whether and to what extent the availability of labile DOM affects benthic NO₃⁻ reduction in seepage faces, a series of flow-through reactor (FTR) experiments with sandy sediment collected from a seepage face was conducted under oxic conditions. Experimental results revealed that the addition of labile DOM (glucose) to porewater did not trigger a significant enhancement in NO₃⁻ reduction rate. In contrast, the aerobic respiration was boosted from ca. 50 to 90 μmol dm⁻³ sediment h⁻¹ by glucose amendments, accounting for approximately 70% consumption of the labile DOM pool. This rapid consumption may increase the NO₃⁻ reducing capability within the sediment, but only indirectly. Together with fluorescent DOM (FDOM) analyses, it can be inferred that NO₃⁻ reducers tend to choose sediment organic matter the prime electron donor under the experimental conditions. As a result, enrichment of DOM in seepage faces, depending on composition, might only stimulate aerobic respiration and nitrification, thus promoting the increase of ensuing NO₃⁻ fluxes to adjacent coastal waters.

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