Freshwater Algae Bellinger, Edward G; Sigee, David C
2010, 2010-04-22
eBook
Freshwater Algae: Identification and Use as Bioindicatorsprovides a comprehensive guide to temperate freshwater algae, with additional information on key species in relation to environmental ...characteristics and implications for aquatic management. The book uniquely combines practical material on techniques and water quality management with basic algal taxonomy and the role of algae as bioindicators. Freshwater Algae: Identification and Use as Bioindicatorsis divided into two parts. Part I describes techniques for the sampling, measuring and observation of algae and then looks at the role of algae as bioindicators and the implications for aquatic management. Part II provides the identification of major genera and 250 important species. Well illustrated with numerous original illustrations and photographs, this reference work is essential reading for all practitioners and researchers concerned with assessing and managing the aquatic environment.
The recent episode in Flint, Michigan, has brought the issue of lead in water into the public eye. But the dangers of lead exposure have been recognized for millennia, and we have the knowledge ...required to redress this social crime — if only we had the political will.
The dangers of lead exposure have been recognized for millennia. In the first century a.d., Dioscorides observed in his
De Materia Medica
that “lead makes the mind give way.” The first industrial hygiene act passed in the colonies, in 1723, prohibited the use of lead in the apparatus used to distill rum, because “the strong liquors and spirits that are distilld through leaden heads or pipes are judged on good grounds to be unwholsom and hurtful.” More recently, large amounts of lead were used to boost the octane rating of gasoline and improve the performance of paint. One would be . . .
Background: The impact of environmental chemicals on children's neurodevelopment is sometimes dismissed as unimportant because the magnitude of the impairments are considered to be clinically ...insignificant. Such a judgment reflects a failure to distinguish between individual and population risk. The population impact of a risk factor depends on both its effect size and its distribution (or incidence/prevalence). Objective: The objective was to develop a strategy for taking into account the distribution (or incidence/prevalence) of a risk factor, as well as its effect size, in order to estimate its population impact on neurodevelopment of children. Methods: The total numbers of Full-Scale IQ points lost among U. S. children 0-5 years of age were estimated for chemicals (methylmercury, organophosphate pesticides, lead) and a variety of medical conditions and events (e.g., preterm birth, traumatic brain injury, brain tumors, congenital heart disease). Discussion: Although the data required for the analysis were available for only three environmental chemicals (methylmercury, organophosphate pesticides, lead), the results suggest that their contributions to neurodevelopmental morbidity are substantial, exceeding those of many nonchemical risk factors. Conclusion: A method for comparing the relative contributions of different risk factors provides a rational basis for establishing priorities for reducing neurodevelopmental morbidity in children.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
Exposure to chemical mixtures is recognized as the real-life scenario in all populations, needing new statistical methods that can assess their complex effects.
We aimed to assess the joint effect of ...in utero exposure to arsenic, manganese, and lead on children's neurodevelopment.
We employed a novel statistical approach, Bayesian kernel machine regression (BKMR), to study the joint effect of coexposure to arsenic, manganese, and lead on neurodevelopment using an adapted Bayley Scale of Infant and Toddler Development™. Third Edition, in 825 mother-child pairs recruited into a prospective birth cohort from two clinics in the Pabna and Sirajdikhan districts of Bangladesh. Metals were measured in cord blood using inductively coupled plasma-mass spectrometry.
Analyses were stratified by clinic due to differences in exposure profiles. In the Pabna district, which displayed high manganese levels interquartile range (IQR): 4.8, 18 μg/dl, we found a statistically significant negative effect of the mixture of arsenic, lead, and manganese on cognitive score when cord blood metals concentrations were all above the 60th percentile (As≥0.7 μg/dl, Mn≥6.6 μg/dl, Pb≥4.2 μg/dl) compared to the median (As=0.5 μg/dl, Mn=5.8 μg/dl, Pb=3.1 μg/dl). Evidence of a nonlinear effect of manganese was found. A change in log manganese from the 25th to the 75th percentile when arsenic and manganese were at the median was associated with a decrease in cognitive score of −0.3 (−0.5, −0.1) standard deviations. Our study suggests that arsenic might be a potentiator of manganese toxicity.
Employing a novel statistical method for the study of the health effects of chemical mixtures, we found evidence of neurotoxicity of the mixture, as well as potential synergism between arsenic and manganese. https://doi.org/10.1289/EHP614.
Celotno besedilo
Dostopno za:
CEKLJ, DOBA, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
The apparent increase in recent decades in the incidence of autism spectrum disorder (ASO) has prompted speculation that concurrent changes in an environmental-chemical exposure might be ...contributory. Indeed, many chemicals have now been linked to ASD, including air pollution, pesticides, metals, and phthalates. In this issue of JAMA Pediatrics, a study by Liew and colleagues adds lithium to this list, suggesting an association between a woman's exposure to lithium in drinking water during pregnancy and ASD risk in her child. This is an excellent records-linkage, population-based, nested case-control study conducted in Denmark that included 8842 cases of ASD (InternatIonal Statistical Classification of Diseases and Related Health Problems, Tenth Revision code) and 43 864 control participants matched to cases by birth year (2000 to 2013) and sex. it used measurements previously made by some of the authors of lithium concentration in 151 public waterworks (mostly in 2013) that, in aggregate, provide water to 50% of the Danish population. A kriging model was used to estimate the lithium concentrations in the water supplies not sampled.
We remain far from achieving the goal of eliminating lead-associated neurodevelopmental morbidities in children. New evidence regarding the blood lead levels at which morbidities occur have led to ...calls for the Centers for Disease Control and Prevention to reduce the current screening guideline of 10 microg/dl. The review evaluates the basis for these calls.
Adverse outcomes, such as reduced intelligence quotient and academic deficits, occur at levels below 10 microg/dl. Some studies suggest that the rate of decline in performance is greater at levels below 10 microg/dl than above 10 microg/dl, although a plausible mechanism has not been identified. Increased exposure is also associated with neuropsychiatric disorders such as attention deficit hyperactivity disorder and antisocial behavior. Functional imaging studies are beginning to provide insight into the neural substrate of lead's neurodevelopmental effects. Current protocols for chelation therapy appear ineffective in preventing such effects, although environmental enrichment might do so.
No level of lead exposure appears to be 'safe' and even the current 'low' levels of exposure in children are associated with neurodevelopmental deficits. Primary prevention of exposure provides the best hope of mitigating the impact of this preventable disease.
This review surveys the recent literature on the neurodevelopmental impacts of chemical exposures during pregnancy. The review focuses primarily on chemicals of recent concern, including phthalates, ...bisphenol-A, polybrominated diphenyl ethers, and perfluorinated compounds, but also addresses chemicals with longer histories of investigation, including air pollutants, lead, methylmercury, manganese, arsenic, and organophosphate pesticides. For some chemicals of more recent concern, the available literature does not yet afford strong conclusions about neurodevelopment toxicity. In such cases, points of disagreement among studies are identified and suggestions provided for approaches to resolution of the inconsistencies, including greater standardization of methods for expressing exposure and assessing outcomes.
Studies of early-life neurotoxicant exposure have not been designed, analyzed, or interpreted in the context of a fully developmental perspective.
The goal of this paper is to describe the key ...principles of a developmental perspective and to use examples from the literature to illustrate the relevance of these principles to early-life neurotoxicant exposures.
Four principles are discussed: 1) the effects of early-life neurotoxicant exposure depend on a child's developmental context; 2) deficits caused by early-life exposure initiate developmental cascades that can lead to pathologies that differ from those observed initially; 3) early-life neurotoxicant exposure has intra-familial and intergenerational impacts; 4) the impacts of early-life neurotoxicant exposure influence a child's ability to respond to future insults. The first principle is supported by considerable evidence, but the other three have received much less attention.
Incorporating a developmental perspective in studies of early-life neurotoxicant exposures requires prospective collection of data on a larger array of covariates than usually considered, using analytical approaches that acknowledge the transactional processes between a child and the environment and the phenomenon of developmental cascades.
Consideration of early-life neurotoxicant exposure within a developmental perspective reveals that many issues remain to be explicated if we are to achieve a deep understanding of the societal health burden associated with early-life neurotoxicant exposures.
•Studies of neurotoxicant exposures have not employed a developmental perspective.•Studies must be designed and analyzed to assess contextual effects on toxicity.•Studies must recognize the phenomenon of developmental cascades.•Studies must acknowledge the transactional nature of early child development.•Health burden will be underestimated if a developmental perspective is not employed.
IMPORTANCE: Exposure of young animals to commonly used anesthetics causes neurotoxicity including impaired neurocognitive function and abnormal behavior. The potential neurocognitive and behavioral ...effects of anesthesia exposure in young children are thus important to understand. OBJECTIVE: To examine if a single anesthesia exposure in otherwise healthy young children was associated with impaired neurocognitive development and abnormal behavior in later childhood. DESIGN, SETTING, AND PARTICIPANTS: Sibling-matched cohort study conducted between May 2009 and April 2015 at 4 university-based US pediatric tertiary care hospitals. The study cohort included sibling pairs within 36 months in age and currently 8 to 15 years old. The exposed siblings were healthy at surgery/anesthesia. Neurocognitive and behavior outcomes were prospectively assessed with retrospectively documented anesthesia exposure data. EXPOSURES: A single exposure to general anesthesia during inguinal hernia surgery in the exposed sibling and no anesthesia exposure in the unexposed sibling, before age 36 months. MAIN OUTCOMES AND MEASURES: The primary outcome was global cognitive function (IQ). Secondary outcomes included domain-specific neurocognitive functions and behavior. A detailed neuropsychological battery assessed IQ and domain-specific neurocognitive functions. Parents completed validated, standardized reports of behavior. RESULTS: Among the 105 sibling pairs, the exposed siblings (mean age, 17.3 months at surgery/anesthesia; 9.5% female) and the unexposed siblings (44% female) had IQ testing at mean ages of 10.6 and 10.9 years, respectively. All exposed children received inhaled anesthetic agents, and anesthesia duration ranged from 20 to 240 minutes, with a median duration of 80 minutes. Mean IQ scores between exposed siblings (scores: full scale = 111; performance = 108; verbal = 111) and unexposed siblings (scores: full scale = 111; performance = 107; verbal = 111) were not statistically significantly different. Differences in mean IQ scores between sibling pairs were: full scale = −0.2 (95% CI, −2.6 to 2.9); performance = 0.5 (95% CI, −2.7 to 3.7); and verbal = −0.5 (95% CI, −3.2 to 2.2). No statistically significant differences in mean scores were found between sibling pairs in memory/learning, motor/processing speed, visuospatial function, attention, executive function, language, or behavior. CONCLUSIONS AND RELEVANCE: Among healthy children with a single anesthesia exposure before age 36 months, compared with healthy siblings with no anesthesia exposure, there were no statistically significant differences in IQ scores in later childhood. Further study of repeated exposure, prolonged exposure, and vulnerable subgroups is needed.
Childhood Lead Exposure and Adult Outcomes Bellinger, David C
JAMA : the journal of the American Medical Association,
03/2017, Letnik:
317, Številka:
12
Journal Article
Recenzirano
Bellinger comments on the findings of a study by Reuben and colleagues. The study results indicated that among 565 participants in the long-running Dunedin Multidisciplinary Health and Development ...Study in New Zealand, blood lead concentration at 11 years of age was significantly and inversely related to intelligence at 38 years of age. Each 5-µg/dL increase in blood lead concentration at age 11 years was associated with a 1.6-point lower IQ score. A blood lead concentration greater than 10 µg/dL (until 2012 the CDC's "action level") was associated with a reduction of 2.7 points in adult IQ and a reduction of 1.7 points relative to IQ at age 11 years. The latter finding is striking given that in the Dunedin cohort, blood lead concentration at age 11 years was already inversely associated with IQ measured concurrently.
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