Water overexploitation in the Lerma-Chapala Watershed, located in central Mexico, is linked to the development of a strong federal hydrocracy with the mission to capture as much water as possible in order to satisfy s...Water overexploitation in the Lerma-Chapala Watershed, located in central Mexico, is linked to the development of a strong federal hydrocracy with the mission to capture as much water as possible in order to satisfy social and political demands through the construction of dams and irrigation systems. The reduction in freshwater quantity and the deterioration of water quality are the outcome of industrial inflows, agriculture and urban untreated wastewater. This study has been leaded to determine hydrological, water quality, seed bioassays and the lake fisheries＇ decreases throughout its historical tendencies （1980-2004） in relation to changes in water levels. Hydrological data and water samples for chemical analysis, inorganic nutrients and seed bioassay, were taken from 10 sites alongside the river and two sites from Lake Chapala in years 2005 and 2009, the WQINsF （National Sanitation Foundation Water Quality Index） was estimated. The dissolved oxygen along the river was from anoxic （0.4） to 7 mg/L and the lake had 6.75 mg/L to 7.36 mg/L; the river had highest nutrients variations, Ntot and Ptot 1 mg/L to 〉 10 mg/L. The lake had few physicochemical variations and the lowest nutrient concentrations; WQINsF （water quality index） in the river-lake system showed very bad-bad quality and contamination in river, bad quality-light contamination in lake. Seed bioassays showed inhibition of root elongation and declining fisheries when low water levels were presented. Chapala Lake had better physicochemical and limnological conditions because of the wind action and water column mixing; in contrast the river, high hidrological variations caused by water administration in middle basin.展开更多
The increase in prevalence of environmental pollution, especially soil contamination with toxic metals has led to their uptake in the human food chains through plant parts. Accumulation and magnification of heavy meta...The increase in prevalence of environmental pollution, especially soil contamination with toxic metals has led to their uptake in the human food chains through plant parts. Accumulation and magnification of heavy metals in human tissues through comsuption of herbal medicine can cause hazardous impacts on health. Therefore, chemical profiling of four heavy metals (Cu, Cr, Mn and Zn) was undertaken in samples of Azorella spinosa from coast and mountain of Maule Region in Chile. The Cu, Cr, Mn and Zn concentrations were determined in plants of the species Azorella spinosa and their soils of origin. For each plant, the metal contents in the stalk, leaves and soil were determined by flame atomic absorption spectroscopy. The methodology was validated using certified reference material: BIMEP-432 for the plant samples and MESS-1 for the soil samples. The concentration ranges found in the plant tissue were: Cu: 1.2 - 62.5;Cr: 0.2 - 3.2;Mn: 188.6 - 1345.1 and Zn: 7.5 - 55.9 mg·kg-1 (dry weight). For the soil samples, the ranges were: Cu: 6.4 - 81.5;Cr: 4.6 - 50.4;Mn: 335.6 - 1936.1 and Zn: 15.6 - 65.9 mg·kg-1 (dry weight). The results were evaluated statistically (two-way ANOVA) to correlate the Cu, Cr, Mn and Zn concentrations in Azorella spinosa plant tissues with those in the soil samples from the corresponding sampling areas.展开更多
This paper presents a case study that demonstrates how models can be used to support water management decisions before sufficient data to verify the model are available. In developing areas, and for new reservoirs, ex...This paper presents a case study that demonstrates how models can be used to support water management decisions before sufficient data to verify the model are available. In developing areas, and for new reservoirs, extensive data for model calibration and validation are often not available. As a case study we developed a CE-QUAL-W2 model of Aguamilpa Reservoir using minimal data and used the model to create a data acquisition plan to support early planning decisions. We based the model on a two-year period and compared the model results to data recently collected with our acquisition plan. We present how we developed and used the model to design the data acquisition plan which identifies and collects data to update and calibrate the model to support future decisions. We show that a minimally calibrated model based on scarce data can support management decisions and be the first step in a spiral engineering approach to system management. Spiral engineering uses models and data to both support early decisions and to iteratively improve this information to support subsequent decisions and models. This case study can be used as a guide for developing water quality models with minimal data and uses the models to support early decision requirements.展开更多
文摘Water overexploitation in the Lerma-Chapala Watershed, located in central Mexico, is linked to the development of a strong federal hydrocracy with the mission to capture as much water as possible in order to satisfy social and political demands through the construction of dams and irrigation systems. The reduction in freshwater quantity and the deterioration of water quality are the outcome of industrial inflows, agriculture and urban untreated wastewater. This study has been leaded to determine hydrological, water quality, seed bioassays and the lake fisheries＇ decreases throughout its historical tendencies （1980-2004） in relation to changes in water levels. Hydrological data and water samples for chemical analysis, inorganic nutrients and seed bioassay, were taken from 10 sites alongside the river and two sites from Lake Chapala in years 2005 and 2009, the WQINsF （National Sanitation Foundation Water Quality Index） was estimated. The dissolved oxygen along the river was from anoxic （0.4） to 7 mg/L and the lake had 6.75 mg/L to 7.36 mg/L; the river had highest nutrients variations, Ntot and Ptot 1 mg/L to 〉 10 mg/L. The lake had few physicochemical variations and the lowest nutrient concentrations; WQINsF （water quality index） in the river-lake system showed very bad-bad quality and contamination in river, bad quality-light contamination in lake. Seed bioassays showed inhibition of root elongation and declining fisheries when low water levels were presented. Chapala Lake had better physicochemical and limnological conditions because of the wind action and water column mixing; in contrast the river, high hidrological variations caused by water administration in middle basin.
文摘The increase in prevalence of environmental pollution, especially soil contamination with toxic metals has led to their uptake in the human food chains through plant parts. Accumulation and magnification of heavy metals in human tissues through comsuption of herbal medicine can cause hazardous impacts on health. Therefore, chemical profiling of four heavy metals (Cu, Cr, Mn and Zn) was undertaken in samples of Azorella spinosa from coast and mountain of Maule Region in Chile. The Cu, Cr, Mn and Zn concentrations were determined in plants of the species Azorella spinosa and their soils of origin. For each plant, the metal contents in the stalk, leaves and soil were determined by flame atomic absorption spectroscopy. The methodology was validated using certified reference material: BIMEP-432 for the plant samples and MESS-1 for the soil samples. The concentration ranges found in the plant tissue were: Cu: 1.2 - 62.5;Cr: 0.2 - 3.2;Mn: 188.6 - 1345.1 and Zn: 7.5 - 55.9 mg·kg-1 (dry weight). For the soil samples, the ranges were: Cu: 6.4 - 81.5;Cr: 4.6 - 50.4;Mn: 335.6 - 1936.1 and Zn: 15.6 - 65.9 mg·kg-1 (dry weight). The results were evaluated statistically (two-way ANOVA) to correlate the Cu, Cr, Mn and Zn concentrations in Azorella spinosa plant tissues with those in the soil samples from the corresponding sampling areas.
文摘This paper presents a case study that demonstrates how models can be used to support water management decisions before sufficient data to verify the model are available. In developing areas, and for new reservoirs, extensive data for model calibration and validation are often not available. As a case study we developed a CE-QUAL-W2 model of Aguamilpa Reservoir using minimal data and used the model to create a data acquisition plan to support early planning decisions. We based the model on a two-year period and compared the model results to data recently collected with our acquisition plan. We present how we developed and used the model to design the data acquisition plan which identifies and collects data to update and calibrate the model to support future decisions. We show that a minimally calibrated model based on scarce data can support management decisions and be the first step in a spiral engineering approach to system management. Spiral engineering uses models and data to both support early decisions and to iteratively improve this information to support subsequent decisions and models. This case study can be used as a guide for developing water quality models with minimal data and uses the models to support early decision requirements.
