Impacts of Desalination Brine Discharge on Benthic Ecosystems

Seawater reverse osmosis (SWRO) desalination facilities produce freshwater and, at the same time, discharge hypersaline brine that often includes various chemical additives such as antiscalants and coagulants. This dense brine can sink to the sea bottom and creep over the seabed, reaching up to 5 km from the discharge point. Previous reviews have discussed the effects of SWRO desalination brine on various marine ecosystems, yet little attention has been paid to the impacts on benthic habitats. This review comprehensibly discusses the effects of SWRO brine discharge on marine benthic fauna and flora. We review previous studies that indicated a suite of impacts by SWRO brine on benthic organisms, including bacteria, seagrasses, polychaetes, and corals. The effects within the discharge mixing zones range from impaired activities and morphological deformations to changes in the community composition. Recent modeling work demonstrated that brine could spread over the seabed, beyond the mixing zone, for up to several tens of kilometers and impair nutrient fluxes from the sediment to the water column. We also provide a possible perspective on brine's impact on the biogeochemical process within the mixing zone subsurface. Desalination brine can infiltrate into the sandy bottom around the discharge area due to gravity currents. Accumulation of brine and associated chemical additives, such as polyphosphonate-based antiscalants and ferric-based coagulants in the porewater, may change the redox zones and, hence, impact biogeochemical processes in sediments. With the demand for drinking water escalating worldwide, the volumes of brine discharge are predicted to triple during the current century. Future efforts should focus on the development and operation of viable technologies to minimize the volumes of brine discharged into marine environments, along with a change to environmentally friendly additives. However, the application of these technologies should be partly subsidized by governmental stakeholders to safeguard coastal ecosystems around desalination facilities.

Tar pollution event (2021) at the Southeastern Levantine oligotrophic basin, short-term impacts and operational oceanography perspectives

The Levantine basin (LB) in the Southeastern Mediterranean Sea is a high-risk oil pollution hot spot owing to its dense maritime traffic and intense oil and gas exploration and exploitation activities. In February 2021 the Israeli LB shorelines were impacted by an exceptional tar pollution event (~550 tons; average distribution: ~3 kg tar m-1 front beach) of an unknown oil spill source. Here we report on the immediate numerical modelling assessment of the oil spill propagation and tar distribution; operational use of underwater gliders for tracking water column anomalies of dissolved polycyclic aromatic hydrocarbons (PAHs) and turbidity signals; the beached tar composition and amounts and the short-term response of the microbial population along the ~180 km shoreline. This pollution event emphasizes the need for improving the early warning systems for oil spills and implementing continuous operational monitoring at high-risk, ecologically sensitive and valuable resource areas like the Israeli LB waters.

A220 AN UNEXPECTED CAUSE OF ACUTE JAUNDICE IN A POST-TRANSPLANT PATIENT

Background

Complications post liver transplantation are common. These may include thromboses, primary graft nonfunction, biliary complications, chylothorax, infection, and rejection. Hepaticojejunostomy with Roux-en-Y limb is a common technique for pediatric liver transplantation. Complications of hepaticojejunostomy include small bowel obstruction due to incarceration of the Roux-en-Y limb within an internal hernia. Acquired diaphragmatic hernia has previously been reported in liver transplant patients. Here we present a unique case of acute biliary obstruction secondary to incarceration of a Roux limb within an acquired diaphragmatic hernia.

Aims

To describe a unique case of incarcerated Roux-en-Y limb in a diaphragmatic hernia leading to acute jaundice in a pediatric liver transplant patient.

Methods

Retrospective chart review and case review with the surgical and medical teams.

Results

A 14 month old girl with unresectable hepatoblastoma received a living donor, left lateral segment liver transplant using standard venous reconstruction, microvascular plastics arterial reconstruction, and the recipient common hepatic duct was anastomosed to the donor left hepatic duct. Serial ultrasounds showed persistent intrahepatic duct dilatation with cholestasis. Given the concern of biliary obstruction, 10 days post-transplant, she underwent repeat laparotomy and was found to have a dilated common bile duct with a proximal obstruction. A Roux-en-Y hepaticojejunostomy was performed to establish adequate biliary drainage.

Three months post-transplant she developed lung metastases that required wedge resection and chemotherapy. 7 months post-transplant, while admitted for routine chemotherapy she acutely developed jaundice, pruritus, and transaminitis. Liver ultrasound showed an apparent fluid collection at the cut surface of the liver and biliary dilatation. Extrinsic compression of the biliary tree was suspected, and so a percutaneous biliary drain was placed to drain the collection and decompress the biliary system.

Despite improvement in the transaminitis and cholestasis, several days later, she developed severe abdominal pain and associated grunting respirations. An MRI with MRCP to reassess the previous findings and rule out a new intraabdominal cause for her symptoms was completed and unexpectedly showed herniation of her Roux-en-Y limb into a diaphragmatic hernia. She had urgent diaphragmatic hernia repair with reduction of the incarcerated bowel loop, with resolution of her pain and jaundice.

Conclusions

Post liver transplant Roux-en-Y herniation is uncommon, but can occur with internal hernias and in diaphragmatic hernias. This uncommon complication should be considered for the post liver transplant patient with hepaticojejunostomy in the setting of acute jaundice, particularly if accompanied by acute onset abdominal pain and/or increased work of breathing.

Funding Agencies

None

Legacy groundwater pollution as a source of mercury enrichment in marine food web, Haifa Bay, Israel

Haifa Bay (HB), located along the northern Mediterranean shore of Israel was polluted with Hg from a chlor-alkali plant (ECI) and from the Qishon River industries, for decades. From the mid-1980s industrial Hg loads into HB decreased dramatically until their complete cessation in 2000. Consequently, concentrations in marine biota and sediments decreased almost to reference levels. However, during 2006-2014, an unexpected increase of total Hg (THg) concentrations was observed in three commercial fish species collected at northern HB (N.HB). To determine the cause of this increase, THg and methyl Hg (MeHg) were measured in seawater, coastal groundwater, suspended particulate matter, plankton, macroalgae, benthic fauna, and in marine and beach sediments. THg in groundwater and sediments from the vicinity of ECI were extremely high (up to 251 μg L^-1 and 2200 ng g^-1, respectively). MeHg concentrations in groundwater were low and constituted <0.1% of THg, except in the surf zone opposite the ECI, where MeHg constituted 0.2% of the THg. THg and MeHg concentrations were consistently higher in benthic biota and plankton from N.HB and northwards, compared to corresponding samples from southern HB (S.HB) and the reference site (RS). MeHg in bivalves and sponges from N.HB and SZ was higher than from S.HB and RS, despite having similar THg concentrations, which suggests a stronger source of MeHg in N.HB. Our findings suggest that the discharge into N.HB of Hg polluted groundwater under the ECI increased during the period 2006-2014. The Hg was assimilated by plankton or adsorbed onto inorganic particles, which were further ingested by benthic and pelagic consumers, as well as transported northward with the alongshore current. These findings demonstrate for the first time the potential of relic pollution in groundwater to increase heavy metal burdens in local marine food webs.

A134 RATES OF PARENTERAL NUTRITION-ASSOCIATED CHOLESTASIS/LIVER DISEASE AND GROWTH PRE- AND POST-SMOFLIPID INTRODUCTION IN NEONATES AND INFANTS WITH INTESTINAL FAILURE

Background

Parenteral nutrition (PN) is essential for survival in infants with intestinal failure (IF). PN-associated cholestasis (PNAC) and liver disease (PNALD) are life-threatening complications of long-term PN use. SMOFlipid (soybean oil, medium-chain triglycerides, olive oil, and fish oil) has recently been approved as an off-label alternative to the conventional soy-based lipid emulsion (Intralipid). It is thought to have anti-cholestatic properties due to its more diverse lipid composition. Due to its’ recent approval in Canada (2013) and the USA (2016), data remains sparse.

Aims

We aim to determine if infants with IF receiving SMOFlipid had significantly lower rates of PNAC and improved growth compared to those receiving Intralipid.

Methods

All patients (≤1 year old at start of PN therapy) who received PN of any duration at two tertiary pediatric hospitals in Edmonton (2010–2018) were identified from the shared pharmacy database. Those with IF who received one type of PN continuously for ≥6 weeks total were included. Individuals with an initial serum conjugated bilirubin &gt;50 µmol/L and/or who had PN interruptions &gt;5 days were excluded. Data on liver parameters, growth, and complications were collected. Non-parametric tests (Mann-Whitney U test for continuous variables and χ2 test for categorical variables) were used to compare PNAC/PNALD (serum conjugated bilirubin &gt;34umol/L during PN) and growth (weight/length/head circumference z-scores) between SMOFlipid and Intralipid.

Results

1777 patients were reviewed; 40 infants (55% male), median age 4 weeks (range 0–48 weeks) at the time of PN initiation, met the inclusion criteria. Reasons for exclusion (n=1737) were receiving PN &lt;6 weeks total (n=1485), duplicate patients (n=154), receiving multiple types of PN with each less than 6 weeks total (n=62), an initial serum conjugated bilirubin &gt;50umol/L (n=21), more than 5 consecutive days off of PN (n=12), and older than 1 year old at time of PN initiation (n=3). Twenty-one patients (53%) received SMOFlipid, 15 (38%) Intralipid, and 4 (10%) Omegaven for ≥6 weeks. The majority (92%) were in an intensive care unit (neonatal or pediatric). No patients were septic when starting PN. Individuals received PN over a median of 7.9 weeks (range 6–27 weeks).

Conclusions

As expected, neonatal onset intestinal failure is rare in Edmonton. In our tertiary pediatric institutions, 2010–2018, SMOFLipid was the predominant lipid choice for infants with intestinal failure, followed by Intralipid. Omegaven was used rarely. This dataset will now allow us to compare the rates of PNAC at six weeks post-PN initiation and differences in growth between infants with IF receiving SMOFlipid versus the traditional Intralipid in our Canadian setting. Analysis is currently underway.

Funding Agencies

Women and Children’s Health Research Institute (WCHRI) at the University of Alberta

Spatial distribution and sources of organic matter and pollutants in the SE Mediterranean (Levantine basin) deep water sediments

A study of deep sea sediment quality was conducted at 52 stations off the Mediterranean coast of Israel (50-1900m depth). Total Organic Carbon (TOC), Polycyclic Aromatic Hydrocarbons (∑PAHs), Poly Chlorinated Biphenyls (∑PCBs) ranged between 0.58 and 1.44%, 12-190 and <0.3-7.7μgkg^-1, respectively. The TOC distribution indicated the Nile delta as an important source of organic matter and the important effect of topography on deposition patterns in this region. PCBs and PAHs quantitative levels were associated with nearby gas well drilling (well below environmental criteria) and dredge-material dumping sites. A significant correlation between these pollutants and TOC was found in the southernmost stations suggesting a common source. PAHs isomer ratios in most of the stations indicated a petrogenic source, while the contribution of pyrogenic sources appears to be very small. These findings form a sound baseline for assessing the potential impact of future deep sea drilling activities that are expected to increase significantly in the Eastern Mediterranean basin.

Seizure-associated central apnea in a rat model: Evidence for resetting the respiratory rhythm and activation of the diving reflex

Respiratory derangements, including irregular, tachypnic breathing and central or obstructive apnea can be consequences of seizure activity in epilepsy patients and animal models. Periods of seizure-associated central apnea, defined as periods >1s with rapid onset and offset of no airflow during plethysmography, suggest that seizures spread to brainstem respiratory regions to disrupt breathing. We sought to characterize seizure-associated central apneic episodes as an indicator of seizure impact on the respiratory rhythm in rats anesthetized with urethane and given parenteral kainic acid to induce recurring seizures. We measured central apneic period onsets and offsets to determine if onset-offset relations were a consequence of 1) a reset of the respiratory rhythm, 2) a transient pausing of the respiratory rhythm, resuming from the pause point at the end of the apneic period, 3) a transient suppression of respiratory behavior with apnea offset predicted by a continuation of the breathing pattern preceding apnea, or 4) a random re-entry into the respiratory cycle. Animals were monitored with continuous ECG, EEG, and plethysmography. One hundred ninety central apnea episodes (1.04 to 36.18s, mean: 3.2±3.7s) were recorded during seizure activity from 7 rats with multiple apneic episodes. The majority of apneic period onsets occurred during expiration (125/161 apneic episodes, 78%). In either expiration or inspiration, apneic onsets tended to occur late in the cycle, i.e. between the time of the peak and end of expiration (82/125, 66%) or inspiration (34/36, 94%). Apneic period offsets were more uniformly distributed between early and late expiration (27%, 34%) and inspiration (16%, 23%). Differences between the respiratory phase at the onset of apnea and the corresponding offset phase varied widely, even within individual animals. Each central apneic episode was associated with a high frequency event in EEG or ECG records at onset. High frequency events that were not associated with flatline plethysmographs revealed a constant plethysmograph pattern within each animal, suggesting a clear reset of the respiratory rhythm. The respiratory rhythm became highly variable after about 1s, however, accounting for the unpredictability of the offset phase. The dissociation of respiratory rhythm reset from the cessation of airflow also suggested that central apneic periods involved activation of brainstem regions serving the diving reflex to eliminate the expression of respiratory movements. This conclusion was supported by the decreased heart rate as a function of apnea duration. We conclude that seizure-associated central apnea episodes are associated with 1) a reset of the respiratory rhythm, and 2) activation of brainstem regions serving the diving reflex to suppress respiratory behavior. The significance of these conclusions is that these details of seizure impact on brainstem circuitry represent metrics for assessing seizure spread and potentially subclassifying seizure patterns.

Laryngospasm, central and obstructive apnea during seizures: Defining pathophysiology for sudden death in a rat model

Seizure spread into the autonomic nervous system can result in life-threatening cardiovascular and respiratory dysfunction. Here we report on a less-studied consequence of such autonomic derangements-the possibility of laryngospasm and upper-airway occlusion. We used parenteral kainic acid to induce recurring seizures in urethane-anesthetized Sprague Dawley rats. EEG recordings and combinations of cardiopulmonary monitoring, including video laryngoscopy, were performed during multi-unit recordings of recurrent laryngeal nerve (RLN) activity or head-out plethysmography with or without endotracheal intubation. Controlled occlusions of a tracheal tube were used to study the kinetics of cardiac and respiratory changes after sudden obstruction. Seizure activity caused significant firing increases in the RLN that were associated with abnormal, high-frequency movements of the vocal folds. Partial airway obstruction from laryngospasm was evident in plethysmograms and was prevented by intubation. Complete glottic closure (confirmed by laryngoscopy) occurred in a subset of non-intubated animals in association with the largest increases in RLN activity, and cessation of airflow was followed in all obstructed animals within tens of seconds by ST-segment elevation, bradycardia, and death. Periods of central apnea occurred in both intubated and non-intubated rats during seizures for periods up to 33s and were associated with modestly increased RLN activity, minimal cardiac derangements, and an open airway on laryngoscopy. In controlled complete airway occlusions, respiratory effort to inspire progressively increased, then ceased, usually in less than 1min. Respiratory arrest was associated with left ventricular dilatation and eventual asystole, an elevation of systemic blood pressure, and complete glottic closure. Severe laryngospasm contributed to the seizure- and hypoxemia-induced conditions that resulted in sudden death in our rat model, and we suggest that this mechanism could contribute to sudden death in epilepsy.

A methanotroph-based biorefinery: Potential scenarios for generating multiple products from a single fermentation

Methane, a carbon source for methanotrophic bacteria, is the principal component of natural gas and is produced during anaerobic digestion of organic matter (biogas). Methanotrophs are a viable source of single cell protein (feed supplement) and can produce various products, since they accumulate osmolytes (e.g. ectoine, sucrose), phospholipids (potential biofuels) and biopolymers (polyhydroxybutyrate, glycogen), among others. Other cell components, such as surface layers, metal chelating proteins (methanobactin), enzymes (methane monooxygenase) or heterologous proteins hold promise as future products. Here, scenarios are presented where ectoine, polyhydroxybutyrate or protein G are synthesised as the primary product, in conjunction with a variety of ancillary products that could enhance process viability. Single or dual-stage processes and volumetric requirements for bioreactors are discussed, in terms of an annual biomass output of 1000 tonnesyear(-1). Product yields are discussed in relation to methane and oxygen consumption and organic waste generation.

MP11: COMORBID DEPRESSION OR ANXIETY IS ASSOCIATED WITH AORTIC VASCULAR INFLAMMATION AND CORONARY HEART DISEASE BEYOND TRADITIONAL CARDIOVASCULAR RISK FACTORS IN PSORIASIS

Purpose of Study

Psoriasis is a chronic inflammatory disorder associated with vascular inflammation (VI), measured by 18-fluorodeoxyglucose positron emission tomography/computed tomography (18-FDG PET/CT), and increased risk of MI. Patients with psoriasis are more likely to have comorbid depression and anxiety. Whether these comorbidities accelerate the development of CVD in psoriasis is unclear. We hypothesized that aortic VI and coronary plaque burden would be increased in patients with psoriasis who have depression and/or anxiety compared to those with psoriasis who do not.

Methods Used

Patients were prospectively enrolled. Those who reported a history of depression and/or anxiety (n=40) on survey and age- and gender-matched patients who reported no history of psychiatric illness (n=40) were selected. Target-to-Background ratio from 18FDG PET/CT was used to assess aortic VI, and coronary CT angiography scans were analyzed for coronary plaque composition.

Summary of Results

Both aortic VI and coronary plaque burden were higher in psoriasis patients with comorbid depression or anxiety compared to those without (table 1). After adjustment for Framingham Risk Score, body mass index, and statin use; VI (β=0.24, p=0.02), total plaque burden (β=0.13, p=0.04), and non-calcified burden (β=0.13, p=0.04) were associated with comorbid depression and/or anxiety.

Conclusions

Patients with psoriasis who have comorbid depression or anxiety have increased aortic VI and coronary plaque burden, suggesting that identification of psychiatric diagnoses in psoriasis may be warranted for future CV risk reduction in this high risk population.

Abstract MP11 Figure 1

21: DETERMINANTS OF VASCULAR INFLAMMATION BY 18-FLUORODEOXYGLUCOSE PET/MRI: FINDINGS FROM THE PSORIASIS, ATHEROSCLEROSIS AND CARDIOMETABOLIC DISEASE INITIATIVE

Purpose of Study

Psoriasis (PSO), a chronic inflammatory disease associated with increased CV risk, provides a clinical human model to study inflammatory atherogenesis. We aimed to assess the major determinants of vascular inflammation (VI) measured by 18FDG PET-MRI in a well-phenotyped PSO cohort.

Methods Used

124 consecutive patients with PSO underwent 18FDG PET-MRI scans. We used target-to-background ratio to quantify VI 120 minutes post FDG injection. Homeostatic model assessment of insulin resistance (HOMA-IR) was measured, along with cholesterol efflux capacity (CEC) and HDL particle concentration by NMR (Liposcience) fasting.

Summary of Results

Our cohort was middle aged (mean 49±13.3 years) with mild to moderate PSO, and low CV risk (median Framingham Risk Score (FRS) 2, IQR 2–6). PSO was associated with increased VI (β=0.27, p<0.005), compared to healthy controls. VI was associated with HOMA-IR (β=0.26, p<0.001), CEC (β=−0.12, p=0.04) and HDL particle concentration (β=−0.19, p=0.003) beyond traditional CV risk factors (age, gender, FRS and BMI). Among these, HOMA-IR provided maximum incremental value in predicting VI beyond traditional risk factors (χ2=39.36, p<0.001).

Conclusions

VI by FDG PET MRI is associated with traditional CV risk factors and cardiometabolic parameters. Insulin resistance and CEC were most strongly associated with VI by 18FDG PET-MRI beyond traditional CV risk factors and BMI in PSO suggesting that cardiometabolic disease increases CV risk in PSO.

Abstract 21 Figure 1

23: VASCULAR INFLAMMATION AND AORTIC WALL CHARACTERISTICS MODULATE FOLLOWING LIFESTYLE CHANGES IN PSORIASIS PATIENTS AT 1 YEAR FOLLOW UP

Purpose of Study

Psoriasis (PSO), a chronic inflammatory skin disease, is associated with increased CV risk and vascular inflammation (VI). However, the effect of therapeutic lifestyle changes (TLC) including exercise on VI over time is unknown. We hypothesized that TLC would lead to an improvement in VI at 1 year accompanied by improvements in aortic wall characteristics.

Methods Used

65 PSO patients, recruited consecutively, underwent FDG PET/CT, phase contrast MRI scans and clinical visits for evaluation of VI, wall characteristics and exercise frequency, at baseline and 1 year follow-up. VI was measured as Target-to-background ratio (TBR), and aortic distensibility (AD) and wall thickness were assessed by commercial software on phase contrast MRI scans. Clinical parameters were ascertained by both survey and provider.

Summary of Results

VI decreased at 1 year (6.5% decrease in TBR; p<0.0001), and was inversely associated with exercise frequency beyond adjustment for CV risk factors (β=−0.27; p=0.001). Furthermore, this decrease in VI was associated with improvement in AD (40% increase; p<0.001) and aortic wall thickness (8.5% decrease; p<0.001).

Conclusions

Our findings suggest that VI improves with TLC. This 6.5% decrease in VI could lead to ∼30% reduction in future adverse events, based on a recent large prospective study. This VI reduction is also associated with improved aortic wall characteristics suggesting that targeting VI as a surrogate marker holds promise to understand the effects of TLC on CV disease.

Abstract 23 Figure 1

18: IMPROVEMENT IN PSORIASIS SKIN DISEASE SEVERITY IS ASSOCIATED WITH REDUCTION OF CORONARY PLAQUE BURDEN

Purpose of Study

Psoriasis (PSO), a chronic inflammatory disease associated with increased cardiovascular (CV) risk, provides a clinical human model to study inflammatory atherogenesis. While PSO severity is associated with both in vivo vascular disease and future CV risk, the longitudinal impact of PSO severity on coronary disease progression is unknown. We hypothesized that an improvement in PSO severity may lead to a reduction in coronary plaque burden by coronary CT angiography (CCTA).

Methods Used

Consecutively recruited PSO patients (N=50) underwent CCTA (320 detector row, Toshiba) and cardiometabolic profiling at baseline and 1-year follow-up. Total (TB) and non-calcified (NCB) coronary plaque burden were quantified using QAngio (Medis, Netherlands). PSO severity was measured as the psoriasis area severity index (PASI). The longitudinal change in coronary plaque burden was analyzed with unadjusted and adjusted regression.

Summary of Results

The cohort had a low Framingham Risk Score and mild to moderate PSO. Patients whose PSO severity improved (ΔPASI −27%; p<0.001) (N=33) had significant improvement in TB (β=0.40, p=0.003) and NCB (β=0.49, p<0.001) (table 1), beyond adjustment for traditional CV risk factors, BMI, statin use, & systemic/biologic PSO therapy.

Conclusions

Improvement in PSO severity was associated with improvement in coronary plaque burden by CCTA. Our study suggests that a reduction in skin inflammation may reduce the progression of early, non-calcified coronary plaque. Larger studies are needed to confirm these findings.

Abstract 18 Figure 1

*P-value is calculated by comparing baseline and 1-year follow-up values for variables using paired t-test for continuous variables, and Pearson's chi-squared test for categorical variables. All values are expressed as Mean±SD, unless specified otherwise. PASI: Psoriasis Area Severity Index.