The objective of this study was to assess the levels of soil contamination and child exposure in ... more The objective of this study was to assess the levels of soil contamination and child exposure in areas next to a primary smelter (arsenic-copper metallurgical) located in the community of Morales in San Luis Potosi, Mexico. In Morales, 90% of the soil samples studied in this work were above 400 mg/kg of lead, and above 100 mg/kg of arsenic, which are guidelines recommended by the United States Environmental Protection Agency (EPA). Bioaccessibility of these metals was studied in vitro in 10 soil samples; the median values of bioaccessibility obtained in these samples were 46.5% and 32.5% for arsenic and lead. Since the concentrations of arsenic and lead in soil were above normal values, and taking into account the bioaccessibility results, exposure to these metals was evaluated in children. Regarding lead, children aged 3-6 years had the highest mean blood lead levels; furthermore, 90% of them had concentrations above 10 mg/dl (CDC's action level). Total urinary arsenic was higher in children aged 8-9 yr; however, the percentage of children with concentrations above 50 mg/g creatinine (CDC's action level) or 100 mg/g creatinine (World Health Organization [WHO] action level) was similar among different age groups. Using the EPAs integrated exposure uptake biokinetic model for lead in children (IEUBK), we estimated that 87% of the total lead in blood is obtained from the soil/dust pathway. The exposure dose to arsenic, estimated for the children living in Morales using Monte Carlo analysis and the arsenic concentrations found in soil, was above the EPA's reference dose. With all these results, it is evident that studies are needed in order to identify adverse health effects in children living in Morales; nevertheless, it is more important to develop a risk reduction program as soon as possible. r
*. Arturo López Torres is a Professor of Law and Associate Dean for Library and Computing at Texa... more *. Arturo López Torres is a Professor of Law and Associate Dean for Library and Computing at Texas Tech University. He was the former Director of the Law Library and Computing at Gonzaga University. Mary Kay Lundwall is a Professor of Law at Florida Coastal School of Law.
Carbon sequestration in forest sinks is an important strategy to remove greenhouse gases and to m... more Carbon sequestration in forest sinks is an important strategy to remove greenhouse gases and to mitigate climate change; however its implementation has been limited under the Clean Development Mechanism of the Kyoto Protocol which has not created the incentives for widespread implementation. The objective of this paper is to analyze the sequestration costs of agroforestry afforestation and reforestation projects (ARPs) following a partial market equilibrium using average cost curves and economic break even analysis to identify the supply costs. The modelling done in this work contrasts the voluntary and clean development mechanism transaction costs. Data is based on the voluntary project, Scolel Té, being implemented in Mexico. Cost curves are developed for seven different sequestration options considering transaction and implementation costs; information from agricultural production in Chiapas Mexico is used to integrate opportunity costs of two agroforestry practices suggesting that sequestration costs may follow a "U" shape, with an initial reduction due to economies of scale and a subsequent increase caused by high opportunity costs. The widespread implementation of agroforestry options not requiring complete land conversion (e.g. living fences and coffee under shade) might be cost effective strategies not generating high opportunity costs. Results also suggest that payments in the early years of the project and lower transaction costs favour the development of ARPs in the voluntary market especially in marginal rural areas with high discount rates.
To improve understanding of the causes of morbidity and mortality among critically ill children i... more To improve understanding of the causes of morbidity and mortality among critically ill children in the countries studied. Survey of hospital records between 1992 and 1994. Six pediatric intensive care units (ICUs) (four ICUs in Mexico City and two ICUs in Ecuador). Consecutive patients (n = 1,061) admitted to the units studied. None. The mortality rate for low-risk patients (pediatric Risk of Mortality [PRISM] score of < or = 10, n = 701) was more than four times the rate predicted by the PRISM score (8.1% vs. 1.8%, p < .001), with an additional 11.3% of this group incurring major morbidity. The mortality rate for moderate-risk patients (PRISM scores of 11 to 20, n = 232) was more than twice predicted (28% vs. 12%, p < .001). For low-risk patients, death was significantly associated with tracheal intubation, central venous cannulation, pneumonia, age of < 2 months, use of more than two antibiotics, and nonsurgical diagnosis (after controlling for PRISM score). Central venous cannulation and tracheal intubation in the lower-risk groups were performed more commonly in units in Mexico than in one comparison unit in the United States (p < .001). For six pediatric ICUs in Mexico and Ecuador, mortality was significantly higher than predicted among lower-risk patients. Tracheal intubation, central catheters, pneumonia, sepsis, and nonsurgical status were associated with poor outcome for low-risk groups. We speculate that reducing the use of invasive central catheters and endotracheal intubation for lower-risk patients, coupled with improved infection control, could lower mortality rates in the population studied.
The objective of this study was to assess the levels of soil contamination and child exposure in ... more The objective of this study was to assess the levels of soil contamination and child exposure in areas next to a primary smelter (arsenic-copper metallurgical) located in the community of Morales in San Luis Potosi, Mexico. In Morales, 90% of the soil samples studied in this work were above 400 mg/kg of lead, and above 100 mg/kg of arsenic, which are guidelines recommended by the United States Environmental Protection Agency (EPA). Bioaccessibility of these metals was studied in vitro in 10 soil samples; the median values of bioaccessibility obtained in these samples were 46.5% and 32.5% for arsenic and lead. Since the concentrations of arsenic and lead in soil were above normal values, and taking into account the bioaccessibility results, exposure to these metals was evaluated in children. Regarding lead, children aged 3-6 years had the highest mean blood lead levels; furthermore, 90% of them had concentrations above 10 mg/dl (CDC's action level). Total urinary arsenic was higher in children aged 8-9 yr; however, the percentage of children with concentrations above 50 mg/g creatinine (CDC's action level) or 100 mg/g creatinine (World Health Organization [WHO] action level) was similar among different age groups. Using the EPAs integrated exposure uptake biokinetic model for lead in children (IEUBK), we estimated that 87% of the total lead in blood is obtained from the soil/dust pathway. The exposure dose to arsenic, estimated for the children living in Morales using Monte Carlo analysis and the arsenic concentrations found in soil, was above the EPA's reference dose. With all these results, it is evident that studies are needed in order to identify adverse health effects in children living in Morales; nevertheless, it is more important to develop a risk reduction program as soon as possible. r
*. Arturo López Torres is a Professor of Law and Associate Dean for Library and Computing at Texa... more *. Arturo López Torres is a Professor of Law and Associate Dean for Library and Computing at Texas Tech University. He was the former Director of the Law Library and Computing at Gonzaga University. Mary Kay Lundwall is a Professor of Law at Florida Coastal School of Law.
Carbon sequestration in forest sinks is an important strategy to remove greenhouse gases and to m... more Carbon sequestration in forest sinks is an important strategy to remove greenhouse gases and to mitigate climate change; however its implementation has been limited under the Clean Development Mechanism of the Kyoto Protocol which has not created the incentives for widespread implementation. The objective of this paper is to analyze the sequestration costs of agroforestry afforestation and reforestation projects (ARPs) following a partial market equilibrium using average cost curves and economic break even analysis to identify the supply costs. The modelling done in this work contrasts the voluntary and clean development mechanism transaction costs. Data is based on the voluntary project, Scolel Té, being implemented in Mexico. Cost curves are developed for seven different sequestration options considering transaction and implementation costs; information from agricultural production in Chiapas Mexico is used to integrate opportunity costs of two agroforestry practices suggesting that sequestration costs may follow a "U" shape, with an initial reduction due to economies of scale and a subsequent increase caused by high opportunity costs. The widespread implementation of agroforestry options not requiring complete land conversion (e.g. living fences and coffee under shade) might be cost effective strategies not generating high opportunity costs. Results also suggest that payments in the early years of the project and lower transaction costs favour the development of ARPs in the voluntary market especially in marginal rural areas with high discount rates.
To improve understanding of the causes of morbidity and mortality among critically ill children i... more To improve understanding of the causes of morbidity and mortality among critically ill children in the countries studied. Survey of hospital records between 1992 and 1994. Six pediatric intensive care units (ICUs) (four ICUs in Mexico City and two ICUs in Ecuador). Consecutive patients (n = 1,061) admitted to the units studied. None. The mortality rate for low-risk patients (pediatric Risk of Mortality [PRISM] score of < or = 10, n = 701) was more than four times the rate predicted by the PRISM score (8.1% vs. 1.8%, p < .001), with an additional 11.3% of this group incurring major morbidity. The mortality rate for moderate-risk patients (PRISM scores of 11 to 20, n = 232) was more than twice predicted (28% vs. 12%, p < .001). For low-risk patients, death was significantly associated with tracheal intubation, central venous cannulation, pneumonia, age of < 2 months, use of more than two antibiotics, and nonsurgical diagnosis (after controlling for PRISM score). Central venous cannulation and tracheal intubation in the lower-risk groups were performed more commonly in units in Mexico than in one comparison unit in the United States (p < .001). For six pediatric ICUs in Mexico and Ecuador, mortality was significantly higher than predicted among lower-risk patients. Tracheal intubation, central catheters, pneumonia, sepsis, and nonsurgical status were associated with poor outcome for low-risk groups. We speculate that reducing the use of invasive central catheters and endotracheal intubation for lower-risk patients, coupled with improved infection control, could lower mortality rates in the population studied.
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