Controlling persistent organic pollutants–what next?

Perspectives on future risk assessment and prevention for control of POP's

Insights into the emission reductions of multiple unintentional persistent organic pollutants from industrial activities

Effects of persistent organic pollutants on the thyroid function of the European sea bass ( Dicentrarchus labrax) from the Aegean sea, is it an endocrine disruption?

Background: Disruption of thyroid homeostasis has been indicated in human studies targeting effects of persistent organic pollutants (POPs). Influence on the maternal thyroid system by POPs is of special interest during pregnancy, as such effects could impair infant thyroid homeostasis. Objectives: We investigated the association between POPs and thyroid stimulating hormone (TSH) and thyroid hormones (THs) in mother and child pairs from the Northern Norway Mother-and-Child Contaminant Cohort Study (MISA). Methods: Nineteen POPs and ten thyroid parameters were analysed in serum from 391 pregnant women in their second trimester. In addition, TSH concentrations in heel prick samples from the infants were analysed by the Norwegian Newborn Screening program. Association studies with a multipollutant approach were performed using multivariate analyses; partial least squares (PLS) regression, hierarchical clustering and principle component analysis (PCA). Results: Several POPs were significantly associated to maternal TSH and THs: i) PFOS was positively associated with TSH; ii) PCBs, HCB and nonachlors were inversely associated to T3, T4 and FT4; and, iii) PFDA and PFUnDA were inversely associated to T3 and FT3. After mutual adjustments for the other contaminants, only PFDA and PFUnDA remained significantly associated to T3 and FT3, respectively. Infants born by mothers within the highest TSH quartile had 10% higher mean concentrations of TSH compared to children born by mothers in the lowest TSH quartile. Conclusion: The present results suggest that background exposures to POPs can alter maternal thyroid homeostasis. This research contributes to the understanding of multipollutant exposures using multivariate statistical approaches and highlights the complexity of investigating environmental concentrations and mixtures in regards to maternal and infant thyroid function.

Chapter 7 Persistent Organic Pollutants in Hong Kong

Hazard evaluation of forest combustibles based on the correlation between pyrolysis products and combustion parameters

Considering the explosive growth of the list of persistent organic pollutants (POPs), the scientific community is combatting increasing challenges to protect humans and wildlife from the potentially negative consequences of POPs. Herein, we characterize the main aspects and progress in the ecotoxicology of POPs in avian species since 2000. The majority of previous efforts has revealed the global occurrence of high levels of various POPs in birds. Laboratory research and epidemiological studies imply that POPs exert a broad-spectrum of side-effects on birds by interfering with their endocrine, immune and neural system, reproduction, and development, and growth. However, inconsistent results suggest that the potential effects of POP exposure on the physiological parameters in birds are multifactorial, involving a multitude of biological processes, species-specific differences, gender, age and types of compounds. Great progress has been achieved in identifying the species-specific sensitivity to dioxin-like compounds, which is attributed to different amino acid residues in the ligand-binding domain of the aryl hydrocarbon receptor. Besides the conventional concentration additivity, several studies have suggested that different classes of POPs possibly act synergistically or antagonistically based on their concentration. However, ecotoxicology information is still recorded in a scattered and inadequate manner, including lack of enough avian species, limited number of POPs investigated, and insufficient geographical representation, and thus our understanding of the effects of POPs on birds remains rudimentary, although mechanistic understanding of their mode of action is progressing. Particularly, research on what happens to wild bird populations and their ecosystems under POP stress is still unavailable. Thus, our aim is to predict and trace the effects POPs at different biological organization levels, especially from the molecular, cellular and individual levels to the population, community and ecosystem levels because of the limited and scattered information, as mentioned above.

Primary sources of selected POPs: regional and global scale emission inventories

In the last years, the spatial range (SR) or characteristic travel distance (CTD) of organic chemicals has found increasing scientific interest as an indicator of the long-range transport (LRT) potential and, in combination with persistence, as a kind of 'hazard' indicator on the exposure level. This development coincides with European debates about more effective and more preventive approaches to the chemicals assessment, and about an international, legally-binding instrument for the phase out of persistent organic pollutants (POPs). Persistence and LRT potential are important issues in these debates. Here, the development of the concept of assessing the spatial scale from early ideas in the 1970s and 1980s to recent studies in the field of multimedia fate and transport modeling is summarized. Different approaches to the modeling of environmental transport (advective and dispersive) and different methods for quantifying the SR or CTD are compared. Relationships between SR or CTD and different persistence measures are analyzed. Comparison of these relationships shows that conclusions for chemical assessment should be based on an evaluation of different persistence and spatial scale measures. The use of SR or CTD and persistence as hazard indicators in the chemicals assessment is illustrated.

Persistent organic pollutants (POPs) are long-lived toxic organic compounds and are of major concern for human and ecosystem health. Although the use of most POPs is banned in most countries, some organochlorine pesticides are still being used in several parts of the world. Although environmental levels of some POPs such as polychlorinated biphenyls (PCBs) have declined, newly emerging POPs such as polybrominated diphenyl ethers (PBDEs) have been increasing considerably. Exposure to POPs has been associated with a wide spectrum of effects including reproductive, developmental, immunologic, carcinogenic, and neurotoxic effects. It is of particular concern that neurotoxic effects of some POPs have been observed in humans at low environmental concentrations. This review focuses on PCBs as a representative chemical class of POPs and discusses the possible mode(s) of action for the neurotoxic effects with emphasis on comparing dose-response and structure-activity relationships (SAR) with other structurally related chemicals. There is sufficient epidemiological and experimental evidence showing that PCB exposure is associated with motor and cognitive deficits in humans and animal models. Although several potential mode(s) of actions were postulated for PCB-induced neurotoxic effects, changes in neurotransmitter systems, altered intracellular signalling processes, and thyroid hormone imbalance are predominant ones. These three potential mechanisms are discussed in detail in vitro and in vivo. In addition, SAR was conducted on other structurally similar chemicals to see if they have a common mode(s) of action. Relative potency factors for several of these POPs were calculated based on their effects on intracellular signalling processes. This is a comprehensive review comparing molecular effects at the cellular level to the neurotoxic effects seen in the whole animal for environmentally relevant POPs.

Exposure to persistent organic pollutants (POPs), such as organochlorines (OCs) and polybrominated diphenyl ethers (PBDEs), is associated with adverse health effects in wildlife. Many POPs have been banned and consequently their environmental concentrations have declined. To assess both temporal trends of POPs and their detrimental impacts, raptors are extensively used as biomonitors due to their high food web position and high contaminant levels. White-tailed eagles (WTEs; Haliaeetus albicilla) in the Baltic ecosystem represent a sentinel species of environmental pollution, as they have suffered population declines due to reproductive failure caused by severe exposure to dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCB) during the 1960s through 1980s. However, there is a lack of long-term studies that cover a wide range of environmental contaminants and their effects at the individual level. In this study, we used 135 pooled samples of shed body feathers collected in 1968–2012 from breeding WTE pairs in Sweden. Feathers constitute a temporal archive for substances incorporated into the feather during growth, including corticosterone, which is the primary avian glucocorticoid and a stress-associated hormone. Here, we analysed the WTE feather pools to investigate annual variations in feather corticosterone (fCORT), POPs (OCs and PBDEs), and stable carbon and nitrogen isotopes (SIs; dietary proxies). We examined whether the expected fluctuations in POPs affected fCORT (8–94 pg. mm−1) in the WTE pairs. Despite clear temporal declining trends in POP concentrations (p < 0.01), we found no significant associations between fCORT and POPs or SIs (p > 0.05 in all cases). Our results do not support fCORT as a relevant biomarker of contaminant-mediated effects in WTEs despite studying a highly contaminated population. However, although not detecting a relationship between fCORT, POP contamination and diet, fCORT represents a non-destructive and retrospective assessment of long-term stress physiology in wild raptors otherwise not readily available.

Persistent organic pollutants (POPs) can induce epigenetic changes in the paternal germline. Here, we report that folic acid (FA) supplementation mitigates sperm miRNA profiles transgenerationally following in utero paternal exposure to POPs in a rat model. Pregnant founder dams were exposed to an environmentally relevant POPs mixture (or corn oil) ± FA supplementation and subsequent F1–F4 male descendants were not exposed to POPs and were fed the FA control diet. Sperm miRNA profiles of intergenerational (F1, F2) and transgenerational (F3, F4) lineages were investigated using miRNA deep sequencing. Across the F1–F4 generations, sperm miRNA profiles were less perturbed with POPs+FA compared to sperm from descendants of dams treated with POPs alone. POPs exposure consistently led to alteration of three sperm miRNAs across two generations, and similarly one sperm miRNA due to POPs+FA; which was in common with one POPs intergenerationally altered sperm miRNA. The sperm miRNAs that were affected by POPs alone are known to target genes involved in mammary gland and embryonic organ development in F1, sex differentiation and reproductive system development in F2 and cognition and brain development in F3. When the POPs treatment was combined with FA supplementation, however, these same miRNA-targeted gene pathways were perturbed to a lesser extend and only in F1 sperm. These findings suggest that FA partially mitigates the effect of POPs on paternally derived miRNA in a intergenerational manner.

The purpose of this paper is to determine the volumes of formation of all pollutants and accumulation of persistent organic pollutants (POPs) during the combustion of organic fuel by stationary sources illustrated by the case of Odesa Industrial-And-Urban Agglomeration. Various studies revealed a significant contribution of organic fuel combustion to environmental pollution of urban agglomerations with persistent organic pollutants. In particular, stationary sources of organic fuel combustion emissions, such as power generation furnaces, have begun to be actively considered only in recent years, but remain insufficiently researched and require increased attention. To calculate the annual mass of pollutant emissions, the most comprehensive official methods of inventorying emissions were used. To calculate the accumulation of Persistent Organic Pollutants, the author’s patented calculation method was used. Statistical data on the annual volumes of organic fuel burning by stationary sources in the Odesa agglomeration for 2011–2021 were used to make the calculation (more recent data can’t be used due to limited information in wartime conditions). The research contribution of emissions of POPs in large cities of Ukraine was limited, the identification of POPs in the environment is very expensive. During the research, the mass of emissions of persistent organic pollutants (POPs) from the combustion of all types of organic fuels was determined, and their accumulation trends in the environment were assessed. It was found that the largest amount of these pollutants is released during the combustion of natural gas, which is due to the significantly higher usage volumes of this type of fuel compared to others. At the same time, the ranking results of the pollutants by hazard showed that dioxins rank fifth in terms of hazard level in the case of natural gas. Conversely, when coal is burned, these substances rank second in terms of hazard, but the volume of coal combustion in the Odesa agglomeration has been decreasing. The article also proved that reducing the volume of organic fuel usage in the future leads to a decrease in the accumulated concentrations of persistent organic pollutants in the environment.

Tibetan lake sediment records reveal historical emission and long-range atmospheric transport of chlorinated paraffins

Persistent organic pollutants (POPs) are semivolatile organic compounds of special concern because of their toxicity, persistence, long-range transport and bioaccumulation potential. They are present in the marine environment, notably in coastal areas affected by municipal sewage, agricultural and aquaculture effluents, industry and shipping traffic. The 7,555 km-length coastal region of India is the most vulnerable zone facing frequent geohazards, e.g. tsunami and flooding. It is contaminated from direct discharge of wastes from the densely populated coastal areas, runoff of fertilizers, dumping by vessels, oil spills, deforestation and ill-planned river basin developments. This chapter summarizes the knowlegde on residues of 5 classes of persistent organic pollutants (POPs) such as dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexane and its isomers (HCHs), polycyclic aromatic hydrocarbon and its congeners (PAHs), polychorinated biphenyl and its congeners (PCBs) and polybrominated diphenyl ether and its congeners (PBDEs) in the sediments and in selective biota: bivalve mollusks, fishes and marine mammals. Their potential ecotoxicological impacts on biota have also been assessed based on the sediment quality guidelines (SQG) specified by USEPA (The incidence and severity of sediment contamination in surface waters of the United States, vol 1, National sediment quality survey. EPA 823-R-97-006, Washington, DC, 1997a: Environmental protection agency, National Sediment Quality Survey, App D, Washington DC, 1997b) and by Canadian Council of Ministers of the Environment (CCME, Canadian quality guidelines for the protection of aquatic life-summary tables. Available from. http://www.ccme.ca/assets/pdf/sed summary_table.pdf, 2002).Contribution of DDT and its metabolites, DDT, DDD and DDE residues, varied in different Indian coastal regions predominated by pp′-DDT and pp′-DDD. The measured concentrations of HCHs were lower than DDTs in sediments. HCH and DDT residues in fish from coastal regions of India were lower than those in temperate countries indicating a lower accumulation in tropical fish, which might be ascribed to rapid volatilization of this insecticide in the tropical environment. Distribution of congener profiles of PCBs, PAHs and PBDEs reflects moderate to very low concentrations closely in conformity to other Asian coastal environment. Predominance of highly chlorinated PCB congeners was evident in comparison to lightly chlorinated PCBs, which are less persistent, have lower log ko w and are more volatile than the former. The prevalence of 4–6 aromatic ring PAHs and cross plots of specific isomer ratios such as phenanthrene/anthracene, fluoranthene/pyrene and methylphenanthrene/phenanthrene suggest the predominance of wood and coal combustion sources, where the atmospheric deposition and surface runoff are the the major transport pathways. In case of PBDEs the nature of lesser-brominated congeners may be due to the extensive use of penta-BDE technical mixture or as a result of environmental debromination of higher brominated BDEs. The east coast of India, on an average, is found to be much more contaminated than the western counterpart which might be attributed to residues with their behavior, fate and bioaccumulation in the different trophic levels should be planned. An alarming situation has already emerged due to the presence of pesticide residues in the human breast milk as well as in the blubber of the endangered gangetic dolphin (Platanista gangetica) inhabiting both riverine and estuarine regions of the Ganga River. Hence authors suggest that a regular monitoring, assessment and reporting machineries should be implemented in accordance with appropriate environmental policies, laws and regulations to guarantee health of environment and human.