33 research outputs found
Insufficient evidence for the existence of natural trifluoroacetic acid
Trifluoroacetic acid (TFA) is a persistent and mobile pollutant that is present ubiquitously in the environment. As a result of a few studies reporting its presence in pre-industrial samples and a purported unaccounted source, TFA is often claimed to exist naturally. Here, we examine the evidence for natural TFA by: (i) critically evaluating measurements of TFA in pre-industrial samples; (ii) examining the likelihood of TFA formation by hypothesized mechanisms; (iii) exploring other potential TFA sources to the deep ocean; and (iv) examining global budgets of TFA. We conclude that the presence of TFA in the deep ocean and lack of closed TFA budget is not sufficient evidence that TFA occurs naturally, especially without a reasonable mechanism of formation. We argue the paradigm of natural TFA should no longer be carried forward
Dissolved Organophosphate Esters and Polybrominated Diphenyl Ethers in Remote Marine Environments: Arctic Surface Water Distributions and Net Transport Through Fram Strait
Organophosphate esters (OPEs) have been found in remote environments at unexpectedly high concentrations, but very few measurements of OPE concentrations in seawater are available, and none are available in subsurface seawater. In this study, passive polyethylene samplers (PEs) deployed on deep-water moorings in the Fram Strait and in surface waters of Canadian Arctic lakes and coastal sites were analyzed for a suite of common OPEs. Total OPEs ( ∑11OPE) at deep-water sites were dominated by chlorinated OPEs, and ranged from 6.3 to 440 pg/L. Concentrations were similar in eastern and western Fram Strait. Chlorinated OPEs were also dominant in Canadian Arctic surface waters (mean concentration ranged from \u3c DL to 4400 pg/L), while nonhalogenated alkyl/aryl-substituted OPEs remained low (1.3–55 pg/L), possibly due to the greater long-range transport potential of chlorinated OPEs. Polybrominated diphenyl ethers (PBDEs) were found at much lower concentrations than OPEs
Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study
Summary
Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally.
Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies
have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of
the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income
countries globally, and identified factors associated with mortality.
Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to
hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis,
exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a
minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical
status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary
intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause,
in-hospital mortality for all conditions combined and each condition individually, stratified by country income status.
We did a complete case analysis.
Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital
diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal
malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome
countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male.
Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3).
Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income
countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups).
Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome
countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries;
p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients
combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11],
p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20
[1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention
(ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety
checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed
(ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of
parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65
[0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality.
Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome,
middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will
be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger
than 5 years by 2030
Isolating isomers of perfluorocarboxylates in polar bears (Ursus maritimus) from two geographical locations
Dietary Bioaccumulation of Perfluorophosphonates and Perfluorophosphinates in Juvenile Rainbow Trout: Evidence of Metabolism of Perfluorophosphinates
The perfluorophosphonates (PFPAs) and perfluorophosphinates
(PFPiAs)
are high production volume chemicals that have been observed in Canadian
surface waters and wastewater environments. To examine whether their
occurrence would result in contamination of organisms in aquatic ecosystems,
juvenile rainbow trout (<i>Oncorhynchus mykiss)</i> were
separately exposed to a mixture of C6, C8, and C10 monoalkylated PFPAs
and a mixture of C6/C6, C6/C8, and C8/C8 dialkylated PFPiAs in the
diet for 31 days, followed by 32 days of depuration. Tissue distribution
indicated preferential partitioning to blood and liver. Depuration
half-lives ranged from 3 to 43 days and increased with the number
of perfluorinated carbons present in the chemical. The assimilation
efficiencies (α, 7–34%) and biomagnification factors
(BMFs, 0.007–0.189) calculated here for PFPAs and PFPiAs were
lower than those previously observed for the perfluorocarboxylates
(PFCAs) and perfluorosulfonates (PFSAs) in the same test organism.
Bioaccumulation was observed to decreased in the order of PFSAs >
PFCAs > PFPAs of equal perfluorocarbon chain length and was dependent
on the charge of the polar headgroup. Bioaccumulation of the PFPiAs
was observed to be low due to their rapid elimination via metabolism
to the corresponding PFPAs. Here, we report the first observation
of an <i>in vivo</i> cleavage of the carbon–phosphorus
bond in fish, as well as, the first <i>in vivo</i> biotransformation
of a perfluoroalkyl acid (PFAA). As was previously observed for PFCAs
and PFSAs, none of the BMFs determined here for the PFPAs and PFPiAs
were greater than one, which suggests PFAAs do not biomagnify from
dietary exposure in juvenile rainbow trout
Sedimentary records of contaminant inputs in Frobisher Bay, Nunavut
Contaminants, such as polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), heavy metals, and per and polyfluoroalkyl substances (PFASs), primarily reach the Arctic through long-range atmospheric and oceanic transport. However, local sources within the Arctic also contribute to the levels observed in the environment, including legacy sources and new sources that arise from activities associated with increasing commercial and industrial development. The City of Iqaluit in Frobisher Bay, Nunavut (Canada), has seen rapid population growth and associated development during recent decades yet remains a site of interest for ocean protection, where Inuit continue to harvest country food. In the present study, seven dated marine sediment cores collected in Koojesse Inlet near Iqaluit, and from sites in inner and outer Frobisher Bay, respectively, were analyzed for total mercury (THg), major and trace elements, PAHs, PCBs, and PFASs. The sedimentary record in Koojesse Inlet shows a period of Aroclor 1260-like PCB input concurrent with military site presence in the 1950–60s, followed by decades of input of pyrogenic PAHs, averaging about ten times background levels. Near-surface sediments in Koojesse Inlet also show evidence of transient local-source inputs of THg and PFASs, and recycling or continued slow release of PCBs from legacy land-based sources. Differences in PFAS congener composition clearly distinguish the local sources from long-range transport. Outside Koojesse Inlet but still in inner Frobisher Bay, 9.2 km from Iqaluit, sediments showed evidence of both local source (PCB) and long-range transport. In outer Frobisher Bay, an up-core increase in THg and PFASs in sediments may be explained by ongoing inputs of these contaminants from long-range transport. The context for ocean protection and country food harvesting in this region of the Arctic clearly involves both local sources and long-range transport, with past human activities leaving a long legacy insofar as levels of persistent organic pollutants are concerned
Ecotoxicity assessment and bioconcentration of a highly brominated organophosphate ester flame retardant in two amphibian species
Restrictions on the production and use of some highly toxic and persistent flame retardants has resulted in the increased use of alternative phosphate flame retardants that are less-well characterized. The brominated organophosphate ester flame retardant, tris(tribromoneopentyl) phosphate (CAS 19186-97-1, molecular formula C15H24Br9O4P, molecular weight 1018.47 g/mol, acronym TTBrNP) is a compound with potential to bioaccumulate and disrupt endocrine functions. To determine the toxicity of TTBrNP, two Canadian native amphibian species, Lithobates sylvaticus and L. pipiens, were acutely (embryos and Gosner stage 25 (GS25) tadpoles) or sub-chronically (GS25-41 tadpoles) exposed to the following nominal concentrations of TTBrNP: 0 (water and solvent controls), 30.6, 61.3, 122.5 and 245.0 μg/L. Note, measured concentrations declined with time (i.e., 118%–30% of nominal). There was high survival for both species after acute and sub-chronic exposures, where 75%–100% survived the exposures, respectively. There were no differences in the occurrence of abnormalities or hatchling size between controls and TTBrNP treatments for either species exposed acutely as embryos or tadpoles. Furthermore, after 30 d of sub-chronic exposure of L. pipiens tadpoles to TTBrNP there were no effects on size, developmental stage, liver somatic index or sex ratio. Bioconcentration factors were low at 26 ± 3.1 L/kg ww in tadpoles from all treatments, suggesting biotransformation or limited bioavailability via aquatic exposures. Thus, using two species of anurans at different early larval stages, we found TTBrNP up to 245 μg/L to have no overt detrimental effects on survival or morphological responses that would suggest fitness-relevant consequences
Phosphorus-Containing Fluorinated Organics: Polyfluoroalkyl Phosphoric Acid Diesters (diPAPs), Perfluorophosphonates (PFPAs), and Perfluorophosphinates (PFPIAs) in Residential Indoor Dust
Indoor dust is thought to be a source of human exposure
to perfluorocarboxylates
(PFCAs) and perfluorosulfonates (PFSAs), but exposures to emerging
organofluorine compounds, including precursors to PFCAs and PFSAs
via indoor dust, remain unknown. We report an analytical method for
measuring several groups of emerging phosphorus-containing fluorinated
compounds, including polyfluoroalkyl phosphoric acid diesters (diPAP),
perfluorophosphonates (PFPA), and perfluorophosphinates (PFPIA), as
well as perfluoroethylcyclohexane sulfonate (PFECHS) in indoor dust.
This method was used to analyze diPAP, PFPA, and PFPIA levels in 102
residential dust samples collected in 2007–2008 from Vancouver,
Canada. The results indicated a predominant and ubiquitous presence
of diPAPs (frequency of detection 100%, mean and median ΣdiPAPs
7637 and 2215 ng/g). Previously measured median concentrations of
perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), and fluorotelomer
alcohols (FTOHs) in the same samples were 14–74 times lower
than ΣdiPAP levels, i.e. 71 ng/g PFOS, 30 ng/g PFOA, and 152
ng/g ΣFTOHs. PFPAs and PFPIAs were detected in 62% and 85% of
samples, respectively, at concentrations nearly 3 orders of magnitude
lower than diPAPs (median 2.3 ng/g ΣPFPAs and 2.3 ng/g ΣPFPIAs).
PFECHS was detected in only 8% of dust samples. To the best of our
knowledge, this is the first report of these compounds in indoor dust.
In this study, diPAP concentrations represented 98% ± 7% of the
total measured analytes in the dust samples. Detection of diPAPs at
such high concentrations in indoor dust may represent an important
and as-yet unrecognized indirect source of PFCA exposure in humans,
given the identified biotransformation pathways. Identifying the sources
of diPAPs to the indoor environment is a priority for future research
to improve air quality in households