Assessing the human health impacts of exposure to disinfection by-products — A critical review of concepts and methods

Understanding the public health implications of chemical contamination of drinking water is important for societies and their decision-makers. The possible population health impacts associated with exposure to disinfection by-products (DBPs) are of particular interest due to their potential carcinogenicity and their widespread occurrence as a result of treatments employed to control waterborne infectious disease.We searched the literature for studies that have attempted quantitatively to assess population health impacts and health risks associated with exposure to DBPs in drinking water. We summarised and evaluated these assessments in terms of their objectives, methods, treatment of uncertainties, and interpretation and communication of results.In total we identified 40 studies matching our search criteria. The vast majority of studies presented estimates of generic cancer and non-cancer risks based on toxicological data and methods that were designed with regulatory, health-protective purposes in mind, and therefore presented imprecise and biased estimates of health impacts. Many studies insufficiently addressed the numerous challenges to DBP risk assessment, failing to evaluate the evidence for a causal relationship, not appropriately addressing the complex nature of DBP occurrence as a mixture of chemicals, not adequately characterising exposure in space and time, not defining specific health outcomes, not accounting for characteristics of target populations, and not balancing potential risks of DBPs against the health benefits related with drinking water disinfection. Uncertainties were often poorly explained or insufficiently accounted for, and important limitations of data and methods frequently not discussed. Grave conceptual and methodological limitations in study design, as well as erroneous use of available dose–response data, seriously impede the extent to which many of these assessments contribute to understanding the public health implications of exposure to DBPs. In some cases, assessment results may cause unwarranted alarm among the public and potentially lead to poor decisions being made in sourcing, treatment, and provision of drinking water. We recommend that the assessment of public health impacts of DBPs should be viewed as a means of answering real world policy questions relating to drinking water quality, including microbial contaminants; that they should be conducted using the most appropriate and up-to-date data and methods, and that associated uncertainties and limitations should be accounted for using quantitative methods where appropriate.     

Forests and global change: what can genetics contribute to the major forest management and policy challenges of the twenty-first century?

The conservation and sustainable use of forests in the twenty-first century pose huge challenges for forest management and policy. Society demands that forests provide a wide range of ecosystem services, from timber products, raw materials and renewable energy to sociocultural amenities and habitats for nature conservation. Innovative management and policy approaches need to be developed to meet these often-conflicting demands in a context of environmental change of uncertain magnitude and scale. Genetic diversity is a key component of resilience and adaptability. Overall, forest tree populations are genetically very diverse, conferring them an enormous potential for genetic adaptation via the processes of gene flow and natural selection. Here, we review the main challenges facing our forests in the coming century and focus on how recent progress in genetics can contribute to the development of appropriate practical actions that forest managers and policy makers can adopt to promote forest resilience to climate change. Emerging knowledge will inform and clarify current controversies relating to the choice of appropriate genetic resources for planting, the effect of silvicultural systems and stand tending on adaptive potential and the best ways to harness genetic diversity in breeding and conservation programs. Gaps in our knowledge remain, and we identify where additional information is needed (e.g., the adaptive value of peripheral populations or the genetic determinism of key adaptive traits) and the types of studies that are required to provide this key understanding.     

Association between prenatal exposure to perfluorinated compounds and symptoms of infections at age 1–4 years among 359 children in the Odense Child Cohort

IntroductionPerfluorinated alkylated substances (PFAS) are persistent industrial chemicals that have resulted in global environmental exposures. Previous epidemiological studies have reported possible effects on the immune system after developmental PFAS exposure, but the possible impact on childhood infectious disease is unclear.ObjectivesTo investigate the association between prenatal exposure to PFAS and symptoms of infections at age 1–4 years.MethodsThe Odense Child Cohort is an on-going prospective study on children's health, where serum concentrations of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), perfluorodecanoic acid (PFDA) and perfluorononanoic acid (PFNA) were measured in 649 pregnant women before gestational week 16. Of these women, 359 reported on symptoms of infection in their child every two weeks for a one-year period. The association between prenatal exposure to PFAS and the symptoms was estimated using a logistic regression model and a negative binomial regression model. For the latter, the outcome was reported as an incidence rate-ratio (IRR), and all models were adjusted for maternal age, educational level, parity and child age.ResultsOn average, the children experienced symptoms of infection 23% of the time during one year. PFOS exposure in the high tertile compared to the low tertile was associated with a statistically significant increased proportion of days with fever (IRR: 1.65 (95% CI: 1.24, 2.18), P-trend < 0.001) and an increased odds of experiencing days with fever above the median (OR: 2.35 (95% CI: 1.31, 4.11). The latter tendency was also apparent for PFOA (OR: 1.97 (95% CI: 1.07, 3.62). Further, higher concentrations of PFOS and PFOA tended to increase the number of episodes of co-occurrence of fever and coughing and fever and nasal discharge during the one-year study period.ConclusionWe found a positive association between prenatal exposure to PFOS and PFOA and the prevalence of fever, which may be a sensitive marker of infection. This finding is in agreement with an immunotoxic effect of prenatal exposure to PFAS. The wider implications for childhood infectious disease deserve attention.     

Are the residents of former Yugoslavia still exposed to elevated PCB levels due to the Balkan wars? Part 1: Air sampling in Croatia, Serbia, Bosnia and Herzegovina

Persistent organic pollutants (POPs) spilled into the environment as a result of damaged industrial and military targets, natural resources, and infrastructure during the Balkan wars still pose a problem several years later. The aim of this project was to investigate an extent to which the residents of former Yugoslavia are exposed to elevated levels of POPs as a consequence of the wars. The atmospheric as well as the soil levels of PCBs, OCPs and PAHs were determined in Croatia, Serbia, Bosnia and Herzegovina during five high volume air sampling campaigns in 2003 and 2004. A considerable contamination of several sites was detected (PCB concentrations in the atmosphere ranged between 67 pg m(-3) and 40 ng m(-3) for the sum of 7 indicator congeners) and the levels are reported in this article.     

Mainstreaming local health through herbal gardens in India: a tool to enhance women active agency and primary health care?

In the last few years, an increasing attention has been given to home herbal gardens, especially due to a revived interest in food security and sustainable development. The uses of home herbal gardens and their role in the livelihoods of rural poor uses have been analyzed in the literature. Despite this, few studies focus on the role of home gardens for primary health care and their relevance for the household and women’s health. In addition, any analysis has been carried out on the socioeconomic values of home herbal gardens in respect of the medicinal plants. This article wants to bridge this gap by analyzing the role of herbal gardens in the local livelihoods in rural India (Tamil Nadu state). The article also highlights their impact in terms of health for the local communities, with a special focus on poor rural women. Final conclusions on the relevance of home herbal gardens for primary health care and socioeconomic development of lower castes in India are drawn.     

Long-term exposure to traffic-related PM10 and decreased heart rate variability: Is the association restricted to subjects taking ACE inhibitors?

BackgroundAlterations in heart rate variability (HRV) are a potential link between exposure to traffic-related air pollution and cardiovascular mortality.ObjectivesWe investigated whether long-term exposure to traffic-related PM₁₀ (TPM₁₀) is associated with HRV in older subjects and/or in participants taking specific cardiovascular treatment or with self-reported heart disease.MethodsWe included 1607 subjects from the general population aged 50 to 72 years. These participants from the SAPALDIA cohort underwent ambulatory 24-hr electrocardiogram monitoring. Associations of average annual exposure to TPM₁₀ over 10 years with HRV parameters from time and frequency domains were estimated using multivariable mixed linear models. Effect estimates are expressed as percent changes in geometric means.ResultsHRV was only associated with TPM₁₀ in participants under ACE inhibitor therapy (N = 94). A 1 μg/m³ increment, approximately equivalent to an interquartile range, in 10 year average TPM₁₀ was associated with decrements of 14.5% (95% confidence interval (CI), − 25.9 to − 1.3) in high frequency (HF) power, of 4.5% (− 8.2 to − 0.5) in the standard deviation of all normal-to-normal RR intervals (SDNN), of 10.6% (− 18.5 to − 1.9) in total power (TP) and an increase of 9.2% (0.8 to 20.2) in the LF/HF power ratio.ConclusionsIn the absence of an overall effect our results suggest that alterations in HRV, a measure of autonomic control of the cardiac rhythm, may not be a central mechanism by which long-term exposure to TPM₁₀ increases cardiovascular mortality. Novel evidence on an effect in persons under ACE inhibitor treatment needs to be confirmed in future studies.     

Migration and reclamation in Northeast China in response to climatic disasters in North China over the past 300?years

Climatic disaster-induced migration and its effects on land exploitation of new settlements is a crucial topic that needs to be researched to better understand the impact of climate change and human adaptation. This paper focuses on the process and mechanism of migrant–reclamation in Northeast China in response to climatic disasters over the past 300 years. The research used comparative analysis of key interlinked factors in this response involving drought/flood events, population, cropland area, farmer revolts, administrations establishment, and land reclamation policies. It draws the following conclusions: (1) seven peaks of migrants–reclamation in Northeast China were evident, most likely when frequent climatic disasters happened in North China, such as the drought–flood in 1851–1859, drought in 1875–1877, and drought 1927–1929; (2) six instances of policy transformation adopted to cope with extreme climatic events, including distinctive examples like changing to a firm policy prohibiting migration in 1740 and a subsequent lifting of that prohibition in 1860; and (3) the fast expansion of the northern agricultural boundary since the middle of the nineteenth century in this area benefited from a climate change trend from a cold period into a warm period. Altogether, over the past 300 years, extreme climatic disasters in North China have deepened the contradiction between the limited land resources and the rapidly increasing population and have resulted in migration and reclamation in Northeast China. Climate, policy, and reclamation constructed an organic chain of response that dominated the land use/cover change process of Northeast China.     

Estimating population exposure to ambient polycyclic aromatic hydrocarbon in the United States – Part II: Source apportionment and cancer risk assessment

A revised Community Multiscale Air Quality (CMAQ) model was developed to simulate the emission, reactions, transport, deposition and gas-to-particle partitioning processes of 16 priority polycyclic aromatic hydrocarbons (PAHs), as described in Part I of the two-part series. The updated CMAQ model was applied in this study to quantify the contributions of different emission sources to the predicted PAH concentrations and excess cancer risk in the United States (US) in 2011. The cancer risk in the continental US due to inhalation exposure of outdoor naphthalene (NAPH) and seven larger carcinogenic PAHs (cPAHs) was predicted to be significant. The incremental lifetime cancer risk (ILCR) exceeds 1 × 10^− 5 in many urban and industrial areas. Exposure to PAHs was estimated to result in 5704 (608–10,800) excess lifetime cancer cases. Point sources not related with energy generation and the oil and gas processes account for approximately 31% of the excess cancer cases, followed by non-road engines with 18.6% contributions. Contributions of residential wood combustion (16.2%) are similar to that of transportation-related sources (mostly motor vehicles with small contributions from railway and marine vessels; 13.4%). The oil and gas industry emissions, although large contributors to high concentrations of cPAHs regionally, are only responsible of 4.3% of the excess cancer cases, which is similar to the contributions of non-US sources (6.8%) and non-point sources (7.2%). The power generation units pose the most minimal impact on excess cancer risk, with contributions of approximately 2.3%.     

Non-specific physical symptoms and electromagnetic field exposure in the general population: Can we get more specific? A systematic review

ObjectiveA systematic review of observational studies was performed to address the strength of evidence for an association between actual and perceived exposure to electromagnetic fields (EMF) and non-specific physical symptoms (NSPS) in the general population. To gain more insight into the magnitude of a possible association, meta-analyses were conducted.MethodsLiterature databases Medline, Embase, SciSearch, PsychInfo, Psyndex and Biosis and additional bibliographic sources such as reference sections of key publications were searched for the detection of studies published between January 2000 and April 2011.ResultsTwenty-two studies met our inclusion criteria. Qualitative assessment of the epidemiological evidence showed either no association between symptoms and higher EMF exposure or contradictory results. To strengthen our conclusions, random effects meta-analyses were performed, which produced the following results for the association with actual EMF; for symptom severity: Headache odds ratio (OR) = 1.65; 95% confidence interval (CI) = 0.88–3.08, concentration problems OR = 1.28; 95% CI = 0.56–2.94, fatigue-related problems OR = 1.15; 95% CI = 0.59–2.27, dizziness-related problems OR = 1.38; 95% CI = 0.92–2.07. For symptom frequency: headache OR = 1.01; 95% CI = 0.66–1.53, fatigue OR = 1.12; 95% CI = 0.60–2.07 and sleep problems OR = 1.18; 95% CI = 0.80–1.74. Associations between perceived exposure and NSPS were more consistently observed but a meta-analysis was not performed due to considerable heterogeneity between the studies.ConclusionsThis systematic review and meta-analysis finds no evidence for a direct association between frequency and severity of NSPS and higher levels of EMF exposure. An association with perceived exposure seems to exist, but evidence is still limited because of differences in conceptualization and assessment methods.     

Solar photovoltaic investments and economic growth in EU: Are we able to evaluate the nexus?

A core question in energy economics may be stated as follows: Is the cost–benefit analysis being correctly applied when we encourage investments in renewables, as an alternative to the traditional energy sources? The relationship between energy consumption and economic growth has been extensively treated within economics literature. Yet, literature on the nexus between specific energy sources and GDP is almost inexistent. In this article, we intend to explore the relationship between a certain type of renewable generation technology (solar PV) and GDP. The present and above all the planned energy mix might differ widely from one country to another. Thus, the analysis by source of energy generation becomes a helpful instrument for policy-making. Using a fixed effects panel data methodology and a sample of eighteen EU countries, we find that a 1 % increase in solar PV installed capacity and in electricity production from renewable sources has a positive impact on GDP of 0.0248 and 0.0061 %, respectively. We also conclude that a 1 % growth on greenhouse gas emissions positively affects GDP by 0.3106 %. Further evidence reveals that, in terms of country-specific analysis, Germany, France, Italy and the UK have the most significant estimations for fixed effects. In fact, Germany is a solar PV technology producer, France has a very active nuclear sector, with little pressure for both renewables development and CO₂ reductions, Italy had in this period a strong governmental support to this sector, and the UK has a strong connection between the solar PV and the industry sectors.     

Is the Clean Development Mechanism delivering benefits to the poorest communities in the developing world? A critical evaluation and proposals for reform

This paper explores whether the Clean Development Mechanism (CDM), a flexibility mechanism under the Kyoto Protocol, has contributed to poverty alleviation in countries that host CDM projects. We argue that the CDM should deliver pro-poor benefits to the communities in which projects are established, since poverty alleviation is integral to sustainable development, which is one of the main purposes of the CDM. After briefly discussing the background of the CDM, we discuss assessment difficulties to which research is prone when evaluating CDM projects for alleged sustainable development contributions. Section 4 brings together and analyses available empirical research on the pro-poor benefits the CDM purportedly delivers to host country communities, concluding that the CDM has failed to deliver poverty alleviation. Therefore, without attempting to be exhaustive, we suggest policy reforms that aim to redirect the CDM to those most in need of assistance.     

Clusters of community exposure to coastal flooding hazards based on storm and sea level rise scenarios—implications for adaptation networks in the San Francisco Bay region

Regional Environmental Change - Sea level is projected to rise over the coming decades, further increasing the extent of flooding hazards in coastal communities. Efforts to address potential...     

Everyday vulnerabilities and “social dispositions” in the Malian Sahel,an indication for evaluating future adaptability to water crises?

Since the 1970s, precipitation in the Sahel has decreased and become very irregular, leading to widespread drought, whilst the human need for water has rapidly increased. A new “dispositions”-based approach was adapted in order to analyse human interactions with environmental hazards and applied to the case of Hombori village in north-eastern Mali. This article explores how the population and political stakeholders perceive, live with and respond to the increasing scarcity of water. It also explores how their current vulnerability and ability to cope with variations in available water resources indicate future adaptability to climate shocks. On the one hand, this research shows how the population copes with variations in water resource availability: the population’s socio-spatial organisation explains the inhabitants’ exposure to this problem and some of the factors affecting vulnerability, the elderly and women being the hardest hit. The water issue is generally managed on a “day-to-day” basis and considered a big problem only in the dry season, thus lowering any incentive for self-protection. The main two variables that could explain this kind of risk management are the conflicting local governance and current social rules. On the other hand, the discussion of results, based on a conceptual model of social responses, explains why these current “social dispositions” to cope with and even address the water scarcity issue do not guarantee future adaptability to climate change.