Revista Internacional de Contaminación Ambiental
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Primer registro de concentración de zinc y cobre en Sphyrna tiburo: bioindicador de la salud de la costa de Campeche, México
Get PDFZinc (Zn) and copper (Cu) concentrations were evaluated in 43 samples of liver and 77 of the muscle of the bonnethead shark (Sphyrna tiburo) as an indicator of the health status of Campeche coasts in the years 2015, 2016, and 2019. Inter-tissue comparisons consistently show a lower concentration in muscle (Zn = 19.8 ± 20.3 mg/kg; Cu = 0.67 ± 0.02 mg/kg) compared to liver (Zn = 31.0 ± 18.7 mg/kg; Cu = 3.56 ± 0.97 mg/kg). Zn concentration in the liver was influenced by sex since levels in the liver of females (34.8 ± 19.50 mg/kg) were significantly higher than in males (24.5 ± 15.95 mg/kg). A decrease in the concentration of both metals was observed over the years both in the liver (Zn 2015 = 32.5, 2016 = 31.8, 2019 = 14.7 and Cu 2015 = 3.36, 2016 = 3.89, 2019 = 3.18) and in muscle (Zn 2015 = 15.0, 2016 = 32.0, 2019 = 4.20 and Cu 2015 = 0.69, 2016 = 0.67, 2019 = 0.24). The concentration of Zn and Cu in muscle did not exceed the maximum permissible limits by international standards for human consumption (Zn = 40 mg/kg, Cu = 10 mg/kg). Therefore, S. tiburo, as a bioindicator regarding these two trace elements, currently does not represent a health risk to consumers.Se evaluó la concentración de zinc (Zn) y cobre (Cu) en 43 muestras de hígado y 77 de músculos del tiburón cabeza de pala (Sphyrna tiburo), como indicador del estado de salud de las costas de Campeche durante los años 2015, 2016 y 2019. Las comparaciones entre tejidos muestran consistentemente una menor concentración en el músculo (Zn = 19.8 ± 20.3 mg/kg; Cu = 0.67 ± 0.02 mg/kg) en comparación con el hígado (Zn = 31.0 ± 18.7 mg/kg; Cu = 3.56 ± 0.97 mg/kg). La concentración de Zn en el hígado fue influenciada por el sexo, ya que los niveles de Zn en el hígado de las hembras (34.8 ± 19.50 mg/kg) fue significativamente mayor que en el de los machos (24.5 ± 15.95 mg/kg). Se observó una disminución en la concentración de ambos metales a través de los años tanto en hígado (Zn 2015 = 32.5, 2016 = 31.8, 2019 = 14.7 y Cu 2015 = 3.36, 2016 = 3.89, 2019 = 3.18), como en músculo (Zn2015 = 15.0, 2016 =32.0, 2019 = 4.20 y Cu 2015 = 0.69, 2016 = 0.67, 2019 = 0.24). La concentración de Zn y Cu en músculo no sobrepasó los límites máximos permitidos por normas internacionales para consumo humano (Zn = 40 mg/kg, Cu = 10 mg/kg), por lo tanto, se puede concluir que S. tiburo como bioindicador de salud referente a estos dos oligoelementos, actualmente no representa un riesgo para la salud de los consumidores
Transfer of lead through different trophic levels: Microalgae (Nannochloropsis oculata), rotifer (Brachionus plicatilis), and prawn (Macrobrachium rosenbergii)
No full textAquatic ecosystems suffer alterations by the input of several pollutants as potentially toxic elements which interact with the planktonic community with likelihood of bioconcentration, bioaccumulation, and biomagnification through the trophic chains despite the fact of being in low concentrations. The goal of this study involves assessing the toxicity, bioaccumulation, and transfer of the lead under controlled laboratory conditions by estimating the bioconcentration factor (BCF) and bioaccumulation factor (BAF) in organisms usually used in aquaculture, as Nannochloropsis oculata microalgae, Brachionus plicatilis rotifer, and the Malaysian prawn Macrobrachium rosenbergii. We assessed toxicity, bioconcentration, and transfer of the lead from the microalgae to higher trophic levels, the rotifer, and the prawn larvae. We performed three bioassays: (1) lead-exposed microalgae, (2) rotifer fed with lead-exposed microalgae, and (3) prawn larvae fed with either lead-exposed microalgae or rotifers fed with these microalgae. The toxicity endpoints were obtained for microalgae. The concentration of the lead in all organisms was analyzed by atomic absorption spectrophotometry for estimating BCF and BAF values. The endpoints No Observed Effect Concentration (NOEC) and Effective Concentration 50 (EC50) are 1 and 5.42 mg/L, respectively, for N. oculata. The BCF in the microalgae decreases as lead concentration increases. A BAF of 2948 in rotifers, and a BAF of 42.1 in prawns were obtained. In conclusion, lead can concentrate in microalgae, transfer, and accumulate through consumption toward the consecutive trophic levels, but not among invertebrates due to their detoxification mechanisms.Aquatic ecosystems suffer alterations by the input of several pollutants as potentially toxic elements which interact with the planktonic community with likelihood of bioconcentration, bioaccumulation, and biomagnification through the trophic chains despite the fact of being in low concentrations. The goal of this study involves assessing the toxicity, bioaccumulation, and transfer of the lead under controlled laboratory conditions by estimating the bioconcentration factor (BCF) and bioaccumulation factor (BAF) in organisms usually used in aquaculture, as Nannochloropsis oculata microalgae, Brachionus plicatilis rotifer, and the Malaysian prawn Macrobrachium rosenbergii. We assessed toxicity, bioconcentration, and transfer of the lead from the microalgae to higher trophic levels, the rotifer, and the prawn larvae. We performed three bioassays: (1) lead-exposed microalgae, (2) rotifer fed with lead-exposed microalgae, and (3) prawn larvae fed with either lead-exposed microalgae or rotifers fed with these microalgae. The toxicity endpoints were obtained for microalgae. The concentration of the lead in all organisms was analyzed by atomic absorption spectrophotometry for estimating BCF and BAF values. The endpoints No Observed Effect Concentration (NOEC) and Effective Concentration 50 (EC50) are 1 and 5.42 mg/L, respectively, for N. oculata. The BCF in the microalgae decreases as lead concentration increases. A BAF of 2948 in rotifers, and a BAF of 42.1 in prawns were obtained. In conclusion, lead can concentrate in microalgae, transfer, and accumulate through consumption toward the consecutive trophic levels, but not among invertebrates due to their detoxification mechanisms
The metabolic diversity of soil microbial community in the petroleum exploitation area of Northern Shaanxi, China
Get PDFIn order to explore the changes of soil chemical properties and microbial metabolic diversity under different petroleum pollution levels, conventional soil detection technology and Biolog® technology were used to study the soil chemical properties and microbial community characteristics of the clean soil in the north Shaanxi oilfield under four different petroleum pollution gradients. The results showed that the soil after petroleum pollution had higher total organic carbon content, higher carbon nitrogen ratio and lower total nitrogen content. Petroleum had a significant effect on the metabolic capacity of soil microbial communities from carbon sources and their utilization patterns. There were significant differences in microbial community metabolism in petroleum-contaminated soils at different concentrations, with a decreasing trend with increasing contamination. At the same time, the microbial activity that could utilize carboxylic acid compounds and polymers was higher in the contaminated soil, while the microbial activity that utilized amino acids and carbohydrates was higher in the clean soil. With the increase of pollutant concentration, the metabolic pattern of soil microbial community to carbon sources changed from sugar-based to polymers-based. This indicates that oil pollution has changed the use of some preferred carbon sources by soil microorganisms, and long-term pollution will stabilize the carbon sources available to microorganisms and promote the development of microbial communities that prefer polymeric substances as carbon sources. This provides theoretical guidance and data support for the bioremediation and treatment of petroleum-contaminated soil in loess hilly areas.In order to explore the changes of soil chemical properties and microbial metabolic diversity under different petroleum pollution levels, conventional soil detection technology and Biolog® technology were used to study the soil chemical properties and microbial community characteristics of the clean soil in the north Shaanxi oilfield under four different petroleum pollution gradients. The results showed that the soil after petroleum pollution had higher total organic carbon content, higher carbon nitrogen ratio and lower total nitrogen content. Petroleum had a significant effect on the metabolic capacity of soil microbial communities from carbon sources and their utilization patterns. There were significant differences in microbial community metabolism in petroleum-contaminated soils at different concentrations, with a decreasing trend with increasing contamination. At the same time, the microbial activity that could utilize carboxylic acid compounds and polymers was higher in the contaminated soil, while the microbial activity that utilized amino acids and carbohydrates was higher in the clean soil. With the increase of pollutant concentration, the metabolic pattern of soil microbial community to carbon sources changed from sugar-based to polymers-based. This indicates that oil pollution has changed the use of some preferred carbon sources by soil microorganisms, and long-term pollution will stabilize the carbon sources available to microorganisms and promote the development of microbial communities that prefer polymeric substances as carbon sources. This provides theoretical guidance and data support for the bioremediation and treatment of petroleum-contaminated soil in loess hilly areas
Lining Technology of Saturated Sand Layer Underground Diversion Tunnel and the Measurement of Concrete Lining Thickness
Get PDFIn order to improve the construction technology quality of the diversion tunnel lining in saturated sand stratum, the lining technology of underground diversion tunnel in saturated sand stratum is studied in detail in this paper. Steel trolley is used to complete binding production, and HBT-20 concrete pump is used to transport concrete. Concrete construction starts from bottom plate and side arch. After the construction, the quality of the diversion tunnel lining is tested nondestructively by the impact elastic wave, and the thickness and defects of the lining are analyzed by the reflection characteristics and spectral relationship of the impact elastic wave. The strength of lining concrete is measured by the propagation characteristics of R wave and the relationship between wave velocity and strength. The results show that the maximum additional bending strain of tunnel wall is about 300 με. At measuring point B7, the thickness and strength of concrete lining can be accurately measured by nondestructive quality testing technology.In order to improve the construction technology quality of the diversion tunnel lining in saturated sand stratum, the lining technology of underground diversion tunnel in saturated sand stratum is studied in detail in this paper. Steel trolley is used to complete binding production, and HBT-20 concrete pump is used to transport concrete. Concrete construction starts from bottom plate and side arch. After the construction, the quality of the diversion tunnel lining is tested nondestructively by the impact elastic wave, and the thickness and defects of the lining are analyzed by the reflection characteristics and spectral relationship of the impact elastic wave. The strength of lining concrete is measured by the propagation characteristics of R wave and the relationship between wave velocity and strength. The results show that the maximum additional bending strain of tunnel wall is about 300 με. At measuring point B7, the thickness and strength of concrete lining can be accurately measured by nondestructive quality testing technology
Dietary intake and trophic transfer of cadmium and lead from three daily consumption vegetables in Quito, Ecuador
Get PDFThe presence of toxic metals in vegetables of daily consumption is a concern for human health. Little is known about the concentration of toxic metals in vegetables sold in markets in Quito, Ecuador, and the corresponding risk to the population. This study aimed to measure the concentration of cadmium (Cd), and lead (Pb) in tomatoes, carrots, and lettuce, to estimate the risk for human health, and to determine the trophic transfer factor using Drosophila melanogaster flies. Vegetable samples were obtained from four local markets in Quito to measure the concentration of Cd and Pb (expressed in mg/kg of dry weight) in the vegetables by microwave-assisted acid digestion and atomic absorption spectrophotometry. Drosophila melanogaster flies were fed with contaminated vegetables to determine de trophic transfer factor of metals in the trophic chain. Our results showed the highest accumulation of Pb and Cd occurred in lettuce. In all cases, the Pb and Cd concentrations exceeded the maximum levels established by the Food and Agriculture Organization. However, the daily intake of metals and the health risk index showed no risk from daily consumption. Pb’s trophic transfer factor was excessively high in the tomato-fed flies, showing transference and accumulation in the flies. Cadmium concentration in tomato-fed flies was also the highest among the three vegetables. The trophic chain transfer of toxic metals from vegetables to Drosophila has been observed through a high accumulation of these metals in flies, and this suggests a negative impact on both human health and ecosystems.The presence of toxic metals in vegetables of daily consumption is a concern for human health. Little is known about the concentration of toxic metals in vegetables sold in markets in Quito, Ecuador, and the corresponding risk to the population. This study aimed to measure the concentration of cadmium (Cd), and lead (Pb) in tomatoes, carrots, and lettuce, to estimate the risk for human health, and to determine the trophic transfer factor using Drosophila melanogaster flies. Vegetable samples were obtained from four local markets in Quito to measure the concentration of Cd and Pb (expressed in mg/kg of dry weight) in the vegetables by microwave-assisted acid digestion and atomic absorption spectrophotometry. Drosophila melanogaster flies were fed with contaminated vegetables to determine de trophic transfer factor of metals in the trophic chain. Our results showed the highest accumulation of Pb and Cd occurred in lettuce. In all cases, the Pb and Cd concentrations exceeded the maximum levels established by the Food and Agriculture Organization. However, the daily intake of metals and the health risk index showed no risk from daily consumption. Pb’s trophic transfer factor was excessively high in the tomato-fed flies, showing transference and accumulation in the flies. Cadmium concentration in tomato-fed flies was also the highest among the three vegetables. The trophic chain transfer of toxic metals from vegetables to Drosophila has been observed through a high accumulation of these metals in flies, and this suggests a negative impact on both human health and ecosystems
Mejoramiento de las propiedades físicas y químicas de los suelos ácidos con la aplicación de vinaza
No full textThe objective of this study was to investigate the acidic soil physical and chemical alteration associated to vinasse application under laboratory conditions. The experiment was distributed in a factorial scheme (5 × 3), in a completely randomized design, with four replicates. The beneficial effects of five vinasse doses (without vinasse [0, only water], 50, 100, 150, and 200 m3/ha) in enhancing the physical and chemical properties of three acidic soils: Oxisol (SO), Ultisol (SU), and Argisol (SA) were studied after 30 days of incubation. Soil samples were collected in the 0-20 cm depth layer to determine physical and chemical properties such as pH (CaCl2), total acidity (AT), exchangeable acidity (Al3+), base cations (K+, Ca2+, and Mg2+), sums of bases (SB), cations exchange capacity (CIC), base saturation index (V%), and saturation of potassium (K), calcium (Ca), magnesium (Mg), and aluminum (Al). Results indicated that vinasse application enhanced the physical and chemical properties of the studied soils, since pH, base cations, SB, CIC, V%, and saturation of K, Ca, and Mg were increased, while AT, Al3+, and Al saturation were decreased. The most important effects in the improvement of physical and chemical properties of acidic soils were observed with a dose of 200 m3/ha of vinasse. The findings of this study suggest that vinasse could be a low-cost effective strategy as an alternative source for balancing soil acidity and would be an appropriate option for minimizing environmental pollution.El objetivo de este estudio fue investigar las alteraciones físicas y químicas de los suelos ácidos asociadas a la aplicación de vinaza en condiciones de laboratorio. Los efectos beneficiosos de cinco dosis de vinaza (sin vinaza [0, solamente agua], 50, 100, 150 y 200 m3/ha), fueron estudiadas en el mejoramiento de las propiedades físicas y químicas de tres suelos ácidos: Oxisol (SO), Ultisol (SU) y Argisol (SA), después de 30 días de incubación. Las muestras de suelos fueron recolectadas en la capa de 0-20 cm de profundidad para la determinación de propiedades físicas y químicas como pH (CaCl2), acidez total (AT), acidez intercambiable (Al3+), cationes bases (K+, Ca2+ y Mg2+), suma de bases (SB), capacidad de intercambio catiónico (CIC), índice de saturación de las bases (V%), y saturación de potasio (K), calcio (Ca), magnesio (Mg) y aluminio (Al). Los resultados indicaron que la aplicación de vinaza mejoró las propiedades físicas y químicas de los suelos estudiados, porque se incrementaron tanto el pH como los cationes bases, la SB, la CIC, el V% y la saturación de K, Ca y Mg, y disminuyeron la AT, Al3+ y saturación de Al. Además, los efectos más importantes en el mejoramiento de las propiedades físicas y químicas de los suelos ácidos se observaron en la dosis de 200 m3/ha de vinaza. Los hallazgos de este estudio sugieren que la vinaza podría ser una estrategia efectiva de bajo costo como fuente alternativa para balancear la acidez del suelo y constituiría una opción apropiada para disminuir la contaminación ambiental
Analysis of packaging recycling patterns using mathematical modeling
Get PDFWith the rapid development of online shopping platforms, China’s express industry has embraced explosive growth, but, at the same time, numerous significant social problems also occur. Regarding the problems, how to deal with the large number of packaging from express delivery has become a growing concern for governments, e-commerce platforms, express enterprises, and ordinary consumers. Abandoned express packaging increases the cost of express enterprises and aggravates the environmental burden. Therefore, based on previous research, this paper tried to establish two recycling models and analyze their benefits through mathematical model deduction. By comparing the results, this paper aimed to set up a model to maximize express enterprises’ revenue from recycling packaging. According to the results, regardless of the governmental subsidies, the revenue from recycling packaging was bound up with the environmental awareness of residents and the recycling price. Through the comprehensive analysis, the author hopes that the results could provide express enterprises with the option of the best recycling model in different contexts and help governments formulate more appropriate recycling policies.With the rapid development of online shopping platforms, China’s express industry has embraced explosive growth, but, at the same time, numerous significant social problems also occur. Regarding the problems, how to deal with the large number of packaging from express delivery has become a growing concern for governments, e-commerce platforms, express enterprises, and ordinary consumers. Abandoned express packaging increases the cost of express enterprises and aggravates the environmental burden. Therefore, based on previous research, this paper tried to establish two recycling models and analyze their benefits through mathematical model deduction. By comparing the results, this paper aimed to set up a model to maximize express enterprises’ revenue from recycling packaging. According to the results, regardless of the governmental subsidies, the revenue from recycling packaging was bound up with the environmental awareness of residents and the recycling price. Through the comprehensive analysis, the author hopes that the results could provide express enterprises with the option of the best recycling model in different contexts and help governments formulate more appropriate recycling policies
The optimal allocation method of resources based on the construction of rural ecological civilization
Get PDFOwing to the low rate of utilization of traditional rural resources, it is impossible to allocate resources in areas with a complex agricultural structure. Therefore, this work designs a new method of resource allocation based on the construction of rural ecological civilization. In this work the optimal model of resource allocation under the construction of the rural ecological civilization is designed, the matrix of data of the evaluation index is established and the dimensionless processing is carried out. According to the gray correlation model, the degree of correlation of each evaluation index is calculated, and then the evaluation obstacle factors are calculated, to obtain the evaluation index of the optimal allocation of rural resources. On this basis, objectives of optimization of construction resources are achieved, the principles of optimization of resources are clarified, and finally the optimal allocation of resources based on the construction of rural ecological civilization is realized. The applicability of this method is verified by example analysis. The rate of utilization of rural resources under this method is high. When the regional structure is complex, it can also maintain a good resource allocation effect, demonstrating that research results are of practical importance.Owing to the low rate of utilization of traditional rural resources, it is impossible to allocate resources in areas with a complex agricultural structure. Therefore, this work designs a new method of resource allocation based on the construction of rural ecological civilization. In this work the optimal model of resource allocation under the construction of the rural ecological civilization is designed, the matrix of data of the evaluation index is established and the dimensionless processing is carried out. According to the gray correlation model, the degree of correlation of each evaluation index is calculated, and then the evaluation obstacle factors are calculated, to obtain the evaluation index of the optimal allocation of rural resources. On this basis, objectives of optimization of construction resources are achieved, the principles of optimization of resources are clarified, and finally the optimal allocation of resources based on the construction of rural ecological civilization is realized. The applicability of this method is verified by example analysis. The rate of utilization of rural resources under this method is high. When the regional structure is complex, it can also maintain a good resource allocation effect, demonstrating that research results are of practical importance
Paleoenvironmental record from lake San Lorenzo, Monetbello, Chiapas, Mexico
Get PDFLake San Lorenzo is one of the lakes at the NW karstic plain of the “Parque Nacional Lagunas de Montebello”, Chiapas, Mexico, that currently have eutrophic, turbid waters. To understand the recent history of this lake, multi-elemental contents determined by X-ray fluorescence analysis, organic matter and carbonate contents -determined by loss on ignition-, Corg/N ratios and diatom analyses from a 41 cm-long sedimentary sequence, were performed. The chronology of the sequence was established by one 14C date from the basal sediments, which allowed establishing that the studied record began in 1956. These new data are consistent with previously published analysis of a profile from the nearby Lake Balamtetik, that could not be dated by 14C, therefore this work provides a better chronological resolution of events. The diatom community along the Lake San Lorenzo sequence was dominated by high nutrient tolerant species, which allows inferring that the lake was already turbid and eutrophic since 1956. Erosion indicators (titanium and magnetic susceptibility) allowed identifying two episodes of basin-wide erosion associated with long distance sediment transport to the lake (very likely through the ”Río Grande de Comitán”) the first episode from 1970 to 1985 and the second one from 1990 to 2000.Lake San Lorenzo is one of the lakes at the NW karstic plain of the “Parque Nacional Lagunas de Montebello”, Chiapas, Mexico, that currently have eutrophic, turbid waters. To understand the recent history of this lake, multi-elemental contents determinedby X-ray fluorescence analysis, organic matter and carbonate contents -determined by loss on ignition-, Corg/N ratios and diatom analyses from a 41 cm-long sedimentary sequence, were performed. The chronology of the sequence was established by one 14C date from the basal sediments, which allowed establishing that the studied record began in 1956. These new data are consistent with previously published analysis of a profile from the nearby Lake Balamtetik, that could not be dated by 14C, therefore this work provides a better chronological resolution of events. The diatom community along the Lake San Lorenzo sequence was dominated by high nutrient tolerant species, which allows inferring that the lake was already turbid and eutrophic since 1956. Erosion indicators (titanium and magnetic susceptibility) allowed identifying two episodes of basin-wide erosion associated with long distance sediment transport to the lake (very likely through the ”Río Grande de Comitán”) the first episode from 1970 to 1985 and the second one from 1990 to 2000