Constraining global transport of perfluoroalkyl acids on sea spray aerosol using field measurements.

Perfluoroalkyl acids (PFAAs) are highly persistent anthropogenic pollutants that have been detected in the global oceans. Our previous laboratory studies demonstrated that PFAAs in seawater are remobilized to the air in sea spray aerosols (SSAs). Here, we conducted field experiments along a north-south transect of the Atlantic Ocean to study the enrichment of PFAAs in SSA. We show that in some cases PFAAs were enriched >100,000 times in the SSA relative to seawater concentrations. On the basis of the results of the field experiments, we estimate that the secondary emission of certain PFAAs from the global oceans via SSA emission is comparable to or greater than estimates for the other known global sources of PFAAs to the atmosphere from manufacturing emissions and precursor degradation.

Horizontal and Vertical Distribution of Perfluoroalkyl Acids (PFAAs) in the Water Column of the Atlantic Ocean.

Perfluoroalkyl acids (PFAAs) are widely distributed in the oceans which are their largest global reservoir, but knowledge is limited about their vertical distribution and fate. This study measured the concentrations of PFAAs (perfluoroalkyl carboxylic acids (PFCAs) with 6 to 11 carbons and perfluoroalkanesulfonic acids (PFSAs) with 6 and 8 carbons) in the surface and deep ocean. Seawater depth profiles from the surface to a 5000 m depth at 28 sampling stations were collected in the Atlantic Ocean from ∼50° N to ∼50° S. The results demonstrated PFAA input from the Mediterranean Sea and the English Channel. Elevated PFAA concentrations were observed at the eastern edge of the Northern Atlantic Subtropical Gyre, suggesting that persistent contaminants may accumulate in ocean gyres. The median ΣPFAA surface concentration in the Northern Hemisphere (n = 17) was 105 pg L-1, while for the Southern Hemisphere (n = 11) it was 28 pg L-1. Generally, PFAA concentrations decreased with increasing distance to the coast and increasing depth. The C6-C9 PFCAs and C6 and C8 PFSAs dominated in surface waters, while longer-chain PFAAs (C10-C11 PFCAs) peaked at intermediate depths (500-1500 m). This profile may be explained by stronger sedimentation of longer-chain PFAAs, as they sorb more strongly to particulate organic matter.

Outside the Safe Operating Space of a New Planetary Boundary for Per- and Polyfluoroalkyl Substances (PFAS).

It is hypothesized that environmental contamination by per- and polyfluoroalkyl substances (PFAS) defines a separate planetary boundary and that this boundary has been exceeded. This hypothesis is tested by comparing the levels of four selected perfluoroalkyl acids (PFAAs) (i.e., perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanesulfonic acid (PFHxS), and perfluorononanoic acid (PFNA)) in various global environmental media (i.e., rainwater, soils, and surface waters) with recently proposed guideline levels. On the basis of the four PFAAs considered, it is concluded that (1) levels of PFOA and PFOS in rainwater often greatly exceed US Environmental Protection Agency (EPA) Lifetime Drinking Water Health Advisory levels and the sum of the aforementioned four PFAAs (Σ4 PFAS) in rainwater is often above Danish drinking water limit values also based on Σ4 PFAS; (2) levels of PFOS in rainwater are often above Environmental Quality Standard for Inland European Union Surface Water; and (3) atmospheric deposition also leads to global soils being ubiquitously contaminated and to be often above proposed Dutch guideline values. It is, therefore, concluded that the global spread of these four PFAAs in the atmosphere has led to the planetary boundary for chemical pollution being exceeded. Levels of PFAAs in atmospheric deposition are especially poorly reversible because of the high persistence of PFAAs and their ability to continuously cycle in the hydrosphere, including on sea spray aerosols emitted from the oceans. Because of the poor reversibility of environmental exposure to PFAS and their associated effects, it is vitally important that PFAS uses and emissions are rapidly restricted.

Sea Spray Aerosol (SSA) as a Source of Perfluoroalkyl Acids (PFAAs) to the Atmosphere: Field Evidence from Long-Term Air Monitoring.

The effective enrichment of perfluoroalkyl acids (PFAAs) in sea spray aerosols (SSA) demonstrated in previous laboratory studies suggests that SSA is a potential source of PFAAs to the atmosphere. In order to investigate the influence of SSA on atmospheric PFAAs in the field, 48 h aerosol samples were collected regularly between 2018 and 2020 at two Norwegian coastal locations, Andøya and Birkenes. Significant correlations (p < 0.05) between the SSA tracer ion, Na+, and PFAA concentrations were observed in the samples from both locations, with Pearson's correlation coefficients (r) between 0.4-0.8. Such significant correlations indicate SSA to be an important source of atmospheric PFAAs to coastal areas. The correlations in the samples from Andøya were observed for more PFAA species and were generally stronger than in the samples from Birkenes, which is located further away from the coast and closer to urban areas than Andøya. Factors such as the origin of the SSA, the distance of the sampling site to open water, and the presence of other PFAA sources (e.g., volatile precursor compounds) can have influence on the contribution of SSA to PFAA in air at the sampling sites and therefore affect the observed correlations between PFAAs and Na+.

Influence of Water Concentrations of Perfluoroalkyl Acids (PFAAs) on Their Size-Resolved Enrichment in Nascent Sea Spray Aerosols.

Perfluoroalkyl acids (PFAAs) are persistent organic substances that have been widely detected in the global oceans. Previous laboratory experiments have demonstrated effective enrichment of PFAAs in nascent sea spray aerosols (SSA), suggesting that SSA are an important source of PFAAs to the atmosphere. In the present study, the effects of the water concentration of PFAAs on their size-resolved enrichment in SSA were examined using a sea spray simulation chamber. Aerosolization of the target compounds in almost all sizes of SSA revealed a strong linear relationship with their water concentrations (p < 0.05, r2 > 0.9). The enrichment factors (EF) of the target compounds showed no correlation with their concentrations in the chamber water, despite the concentrations varying by a factor of 500 (∼0.3 to ∼150 ng L-1). The particle surface-area-to-volume ratio appeared to be a key predictor of the enrichment of perfluoroalkyl carboxylic acids (PFCAs) with ≥7 perfluorinated carbons and perfluoroalkanesulfonic acids (PFSAs) with ≥6 perfluorinated carbons in supermicron particles (p < 0.05, r2 > 0.8), but not in submicron particles. The different enrichment behaviors of PFAAs in submicron and supermicron particles might be a result of the different production mechanisms of film droplets and jet droplets. The results suggest that the variability in seawater concentrations of PFAAs has little influence on EFs and that modeling studies designed to quantify the source of PFAAs via SSA emissions do not need to consider this factor.

Environment occurrence of perfluoroalkyl acids and associated human health risks near a major fluorochemical manufacturing park in southwest of China.

Despite China being the largest global manufacturer of perfluoroalkyl acids (PFAAs), few studies have been carried out on the environmental occurrence and associated human health risks of PFAAs emitted from manufacturing sites in China. Here, river water, tap water, soil and leaf samples were collected around a major fluorochemical manufacturing park (FMP) in the southwest of China in 2019. High ΣPFAA concentrations (sum of 12 PFAAs) of 3817 ng/L, 3254 ng/L, 322-476 ng/g dw and 23401-33749 ng/g dw were measured near the FMP in river water, tap water, soil and leaves, respectively, indicating that the FMP is a point source of PFAAs. PFOA was the predominant PFAA in all samples (58.5-98.6 %) indicating the production or use of PFOA at the FMP. PFOA concentrations in most tap water samples (> 300 ng/L in 31 of 38 samples) exceeded the U.S. EPA health advisory. Proportions of branched PFOA isomers in all samples were in 5.9-47.4 %, suggesting the production or use of PFOA manufactured by electrochemical fluorination at the FMP. It is recommended to focus more attention on branched PFOA isomers in the future because otherwise health risks may be underestimated due to their relatively high proportions in China.

Exploring open cheminformatics approaches for categorizing per- and polyfluoroalkyl substances (PFASs).

Per- and polyfluoroalkyl substances (PFASs) are a large and diverse class of chemicals of great interest due to their wide commercial applicability, as well as increasing public concern regarding their adverse impacts. A common terminology for PFASs was recommended in 2011, including broad categorization and detailed naming for many PFASs with rather simple molecular structures. Recent advancements in chemical analysis have enabled identification of a wide variety of PFASs that are not covered by this common terminology. The resulting inconsistency in categorizing and naming of PFASs is preventing efficient assimilation of reported information. This article explores how a combination of expert knowledge and cheminformatics approaches could help address this challenge in a systematic manner. First, the "splitPFAS" approach was developed to systematically subdivide PFASs (for eventual categorization) following a CnF2n+1-X-R pattern into their various parts, with a particular focus on 4 PFAS categories where X is CO, SO2, CH2 and CH2CH2. Then, the open, ontology-based "ClassyFire" approach was tested for potential applicability to categorizing and naming PFASs using five scenarios of original and simplified structures based on the "splitPFAS" output. This workflow was applied to a set of 770 PFASs from the latest OECD PFAS list. While splitPFAS categorized PFASs as intended, the ClassyFire results were mixed. These results reveal that open cheminformatics approaches have the potential to assist in categorizing PFASs in a consistent manner, while much development is needed for future systematic naming of PFASs. The "splitPFAS" tool and related code are publicly available, and include options to extend this proof-of-concept to encompass further PFASs in the future.

Fluorotelomer alcohols (FTOHs), brominated flame retardants (BFRs), organophosphorus flame retardants (OPFRs) and cyclic volatile methylsiloxanes (cVMSs) in indoor air from occupational and home environments.

Indoor air samples were collected from private homes and various occupational indoor environments using passive air sampler and analysed for fluorotelomer alcohols (FTOHs), brominated flame retardants (BFRs), organophosphorus flame retardants (OPFRs) and cyclic volatile methyl siloxanes (cVMSs). The aim was to investigate their occurrence in indoor air, factors that may affect their presence and human daily exposure dose (DED) via inhalation. In general, levels of cVMSs were 3-4 orders of magnitude greater than the other compound classes. OPFRs concentration was found significantly higher than BFRs in indoor air. The most abundant compounds in each chemical class were 8:2 FTOH, 2,4,6-TBP, TNBP and TCEP and decamethylcyclopentasiloxane (D5). Home samples contained higher level of FTOHs, BFRs and cVMSs than occupational environments, whereas concentration of OPFRs in office samples were higher. BFRs concentrations were significantly correlated with building age and with the number of electronic/electrical devices at the sampling sites. Moreover, significantly lower levels of FTOHs and cVMSs were observed in rooms with forced-ventilation system. Estimated DED via inhalation was significantly higher at home than in office and the total DED was on average 3-5 orders of magnitude lower than the reference value.

[In vitro studies on asexual embryos and regenerated plantlets obtained from leaf organ of Panax notoginseng].

OBJECTIVE: To study and improve the tissue culture technology of Panax notoginseng. METHOD: Using the callus of leaf blade and leafstalk of P. notogingseng as explants, MS + 2, 4-D 1.5 mg x L(-1) as basal medium, the formation of asexual embryos was induced by added LFS, BA, KT or ZT 0.5 mg x L(-1), and cultured in dark. It cultured then in 2000 lx of illumination for 10-12 h x d(-1) to induce the asexual embryos germinating and developing to be the regenerated-plantlet. RESULT AND CONCLUSION: Only the medium added with LFS could induce the formation of asexual embryos, and made it developed to be regenerated-plantlet. The inducing ratio of asexual embryos reached about 85%, and 30% of asexual embryos could grow and develop as robust regenerated-plantlets.

Simultaneous pancreas-kidney transplantation with modified enteric drainage of exocrine pancreatic secretion.

BACKGROUND: As a valid therapeutic option for patients with type 1 diabetes mellitus (IDDM) and secondary diabetic nephropathy, simultaneous pancreas-kidney transplantation (SPK) remains more undeveloped than other solid organ transplantations due to the restrictions of surgical techniques especially the modes of exocrine pancreatic secretion. The aim of this paper was to summarize our single-center experience in SPK with modified enteric drainage (ED). METHODS: From June 2000 to July 2003, 10 patients with IDDM associated with uremia received SPK. The pancreatic allograft exocrine secretion was drained into the proximal jejunum via a side-to-side duodenojejunostomy without Roux-en-Y anastomosis. Quadruple immunosuppressive regimen consisted of induction of tacrolimus (TAC)/cyclosporine (CsA), mycophenolate mofetil (MMF), steroids and antibodies, which included antilymphocyte globulin (ALG) or anti-CD25 monoclonal antibody. RESULTS: ED-SPK without Roux-en-Y anastomosis was successful in all 10 patients without serious complications such as pancreatitis, graft thrombosis and pancreatic fistula. The patients regained immediate kidney allograft function and euglycemia with insulin-independence. Four patients survived over one year. Episodes of acute rejection were observed in 4 patients, 3 of whom showed reversion after treatment of OKT3 or insulin. Early postoperative complications included peritoneal infection (2 patients), wound infection (2) and renal hematoma (1). CONCLUSION: ED-SPK without Roux-en-Y anastomosis is safe and preferable to the patients with IDDM associated with uremia.

Combined small bowel and reduced auxiliary liver transplantation: case report.

AIM: To present a case of combined small bowel and reduced auxiliary liver transplantation. METHODS: A 55-year-old patient with short bowel syndrome and TPN-related liver dysfunction received small bowel transplantation combined with a reduced auxiliary liver graft. A liver was added to restore the patient's liver function and to protect the intestinal allograft from rejection. His own liver was not removed. RESULTS: Without donor pretreatment and by conventional immunosuppresive therapy following transplantation, the patient experienced had only one episode of mild intestinal rejection, which was easily reversed by treatment with Methylprednisolone. No liver rejection occurred. Unfortunately, the patient died of heart and lung failure 30d after transplantation, despite successful graft replacement. Histopathologic examination of specimens after death demonstrated normal structure in both intestinal and liver grafts. CONCLUSION: The auxiliary liver graft might play a role in preventing intestinal allograft rejection. However, the observation period in this case is short. Further study is needed to determine the risks, effect on the protecting the small-bowel from rejection, and feasibility of general application of this procedure.

[Selection of surgical procedure of combined kidney-pancreatic transplantation].

OBJECTIVE: To evaluate simultaneous kidney-pancreatic transplantation (SKPT) with bladder drainage and enteric drainage for its efficacy and safety. METHOD: SKPT was performed in 10 patients from Jan. 2000 to Feb. 2002. All patients had long-standing insulin-dependent diabetes mellitus and subsequent renal failure. Bladder drainage (BD) of exocrine secretion was used in the first 2 cases and enteric drainage (ED) in last 8 patients. In BD, a two-layer hand sewn duodenocystostomy was performed. In ED, a two-layered side-to-side anastomosis was fashioned between the donor duodenal segment and the recipient jejunum. No Roux-en-Y limb was used. Quadruple immunosuppressive therapy with antithymocyte globulin, tacrolimus, mycophenolate mofetil and steroids was standard treatment in all patients. The patients were treated with quadruple therapy, which included antilymphocyte globulin (ALG) or anti-CD25 monoclonal antibody (Zenapax) induction therapy, prednisone, Cyclosporine A/tacrolimus, and mycophenolat-mofetil (MMF). RESULTS: SPK was successfully applied to all cases without complication referable to the technique. All patients have achieved excellent renal function and euglycemia, and no further insulin treatment was needed between 1 and 5 days posttransplant. One patient with ED died due to sepsis and upper gastrointestinal hemorrhage 5 weeks after operation. The death occurred with functioning grafts. Until now no rejection episode and thrombosis were observed and all the grafts from nine patients are functioning well. The first 2 patients with BD underwent slight metabolic complications and microscopic hematuria with entire follow-up time. Two episodes of reflux graft pancreatitis followed by macroscopic hematuria occurred in one patient with BD. CONCLUSION: Compared with SPK with BD, ED without Roux-en-Y anastomosis might be a more physiological and prior procedure for type I diabetes mellitus with uremia.

[Comparative study of three kinds of outflow tract reconstruction of hepatic veins in piggyback liver transplantation].

OBJECTIVE: To study the effects of 3 different operational patterns of piggyback liver transplantation (PBLT) used to reconstruct backflow of hepatic veins. METHODS: Sixty-three operations of PBLT were performed on 59 patients with terminal hepatic diseases after three operational patterns: EEAT [the suprahepatic inferior vena cava (sup-H-IVC) of donor is anstomosed with the plasticized hepatic vein of recipient end-to-end, also called standard PBLT, SPBLT] in 17 cases, ESAT (the sup-H-IVC of donor is anastomosed with the sup-H-IVC of recipient end-to-side) in 12 cases, and SSAT [the retrohepatic IVC (RHIVC) of donor is anastomosed with the RHIVC of recipient side-to-side] in 32 cases, the latter two patterns being called ameliorative PBLT (APBLT) jointly. The effects were analyzed. RESULTS: Complications, such as backflow obstruction of hepatic vein and delayed recovery of liver function, were observed in the EEAT and ESAT groups, but not in the SSAT group. CONCLUSION: The SSAT pattern of PBLT is easy to perform and advantageous to avoid the technical maladies of the other 2 patterns and postoperative complications, and provides assurance of recovery after operation.