Long-term effects of an early-life exposure of fathead minnows to sediments containing bitumen. Part I: Survival, deformities, and growth.

The aim of this study was to investigate the long-term effects of a short exposure to natural sediments within the Athabasca oil sand formation to critical stages of embryo-larval development in fathead minnows (Pimephales promelas). Three different sediments were used: Ref sediment from the upper Steepbank River tested at 3 g/L (containing 12.2 ng/g ∑PAHs), and two bitumen-rich sediments tested at 1 and 3 g/L; one from the Ells River (Ells downstream, 6480 ng/g ∑PAHs) and one from the Steepbank River (Stp downstream, 4660 ng/g ∑PAHs). Eggs and larvae were exposed to sediments for 21 days, then transferred to clean water for a 5-month grow-out and recovery period. Larval fish had significantly decreased survival after exposure to 3 g/L sediment from Stp downstream, and decreased growth (length and weight at 16 days post hatch) in Ells and Stp downstream sediments at both 1 and 3 g/L. Decreased tail length was a sensitive endpoint in larval fish exposed to Ells and Stp downstream sediments for 21 days compared to Ref sediment. After the grow-out in clean water, all growth effects from the bitumen-containing sediments recovered, but adult fish from Stp downstream 3 g/L sediment had significant increases in jaw deformities. The study shows the potential for fish to recover from the decreased growth effects caused by sediments containing oil sands-related compounds, but that some effects of the early-life sediment exposure occur later on in adult fish.

Meltwater from snow contaminated by oil sands emissions is toxic to larval fish, but not spring river water.

To assess the toxicity of winter-time atmospheric deposition in the oil sands mining area of Northern Alberta, embryo-larval fathead minnow (Pimephales promelas) were exposed to snowmelt samples. Snow was collected in 2011-2014 near (<7km) oil sands open pit mining operations in the Athabasca River watershed and at sites far from (>25km) oil sands mining. Snow was shipped frozen back to the laboratory, melted, and amended with essential ions prior to testing. Fertilized fathead minnow eggs were exposed (<24h post-fertilization to 7-16days post-hatch) to a range of 25%-100% snowmelt. Snow samples far from (25-277km away) surface mining operations and upgrading facilities did not affect larval fathead minnow survival at 100%. Snow samples from sites near surface mining and refining activities (<7km) showed reduced larval minnow survival. There was some variability in the potencies of snow year-to-year from 2011 to 2014, and there were increases in deformities in minnows exposed to snow from 1 site on the Steepbank River. Although exposure to snowmelt from sites near oil sands surface mining operations caused effects in larval fish, spring melt water from these same sites in late March-May of 2010, 2013 and 2014 showed no effects on larval survival when tested at 100%. Snow was analyzed for metals, total naphthenic acid concentrations, parent PAHs and alkylated PAHs. Naphthenic acid concentrations in snow were below those known to affect fish larvae. Concentrations of metals in ion-amended snow were below published water quality guideline concentrations. Compared to other sites, the snowmelt samples collected close to mining and upgrading activities had higher concentrations of PAHs and alkylated PAHs associated with airborne deposition of fugitive dusts from mining and coke piles, and in aerosols and particles from stack emissions. CAPSULE: Snow collected close to oil sands surface mining sites is toxic to larval fathead minnows in the lab; however spring melt water samples from the same sites do not reduce larval fish survival.

Parasite community similarity in Athabasca River trout-perch (Percopsis omiscomaycus) varies with local-scale land use and sediment hydrocarbons, but not distance or linear gradients.

Parasite communities have been shown to be structured by processes at scales ranging from continental to microhabitat, but few studies have simultaneously considered spatial and environmental variables, measured at different scales, to assess their relative influences on parasite abundance, species richness, and community similarity. Parasite abundance, diversity, and community similarity in Athabasca River trout-perch (Percopsis omiscomaycus) were examined in relation to water quality, substrate profile, metal and organic compound levels in water and sediment, and landscape use patterns at different scales, as well as distance among sites and upstream-downstream position along the river. Although species richness did not differ among sites, there were significant differences in abundance of individual taxa and community structure. We observed a shift from communities dominated by larval trematodes Diplostomum spp. to domination by gill monogeneans Urocleidus baldwini, followed by a reversion further downstream. Variations in the abundance of these taxa and of overall community similarity were strongly correlated with sediment hydrocarbons (alkanes and polycyclic aromatic hydrocarbons (PAHs)) as well as landscape use within 5 km of study sites. No correlations were noted with any other predictors, indicating that parasite populations and communities in this system were likely primarily influenced by habitat level and landscape-scale filters, rather than larger-scale processes such as distance decay or river continuum effects.

Decamethylcyclopentasiloxane (D5) spiked sediment: bioaccumulation and toxicity to the benthic invertebrate Hyalella azteca.

Chronic toxicity and bioaccumulation of decamethylcyclopentasiloxane (D5) to Hyalella azteca was examined in a series of spiked sediment exposures. Juvenile H. azteca were exposed for 28d (chronic) to a concentration series of D5 in two natural sediments of differing organic carbon content (O.C.) and particle size composition. The chronic, LC50s were 191 and 857µgD5g(-1) dry weight for Lakes Erie (0.5% O.C.) and Restoule (11% O.C.) respectively. Inhibition of growth only occurred with the L. Restoule spiked sediment with a resultant EC25 of 821µgg(-1)dw. Lethality was a more sensitive endpoint than growth inhibition. Biota sediment accumulation factors (BSAFs, 28d) were <1 indicating that D5 did not bioconcentrate based on lipid normalized tissue concentrations and organic carbon normalized sediment concentrations. Organic carbon (OC) in the sediment appeared to be protective, however normalization to OC did not normalize the toxicity. Normalization of D5 concentrations in the sediments to sand content did normalize the toxicity and LC50 values of 3180 and 3570µg D5g(-1) sand dw were determined to be statistically the same.

Interactive effects of metals in mixtures on bioaccumulation in the amphipod Hyalella azteca.

Mixtures were produced of "equi-toxic" concentrations of 10 elements at the 4-week LC25 for Hyalella azteca. Bioaccumulation was determined in 1-week exposures. The first mixtures tested included seven elements; As, Cd, Co, Cr, Ni, Pb and Tl. Copper, Mn and Zn were not included in the initial tests due to potential confounding effects, such as regulation of Cu and Zn by H. azteca and the high concentrations of Mn required to be "equi-toxic", which might cause adsorption of metals to Mn hydroxides if these were formed. The second set of tests included the seven element mixture in combination with, Cu, Mn and Zn individually, the binary pairs, Cu-Mn, Cu-Zn and Mn-Zn; and the tertiary group Cu, Mn and Zn. Interaction factors (IF) were computed which quantified each element's impact on the bioaccumulation of the other nine. Cobalt, Cd and Ni bioaccumulation was significantly inhibited with increasing number of metals in the mixture. Arsenic bioaccumulation was enhanced with increasing number of metals in the mixture exposure. Lead bioaccumulation was enhanced by some mixture combinations. Bioaccumulation of Cr, Cu, Mn, Tl and Zn were not significantly affected by exposure to other metals.

Chronic toxicity of arsenic, cobalt, chromium and manganese to Hyalella azteca in relation to exposure and bioaccumulation.

Chronic toxicity of As, Co, Cr and Mn to Hyalella azteca can be described using a saturation-based mortality model relative to total-body or water metal concentration. LBC25s (total-body metal concentrations resulting in 25% mortality in 4 weeks) were 125, 103, 152 and 57,900 nmol g-1 dry weight for As, Co, Cr and Mn respectively. LC50s (metal concentrations in water resulting in 25% mortality in 4 weeks) were 5600, 183, 731, and 197,000 nmol L-1, respectively. A hormesis growth response to As exposure was observed. Growth was a more variable endpoint than mortality for all four toxicants; however, confidence limits based on growth and mortality all overlapped, except Cr which had no effect on growth. Mn toxicity was greater in glass test containers compared to plastic. Bioaccumulation of As, Co, Cr, and Mn was strongly correlated with, and is useful for predicting, chronic mortality.

Reduced metals concentrations of water, sediment and hyalella azteca from lakes in the vicinity of the sudbury metal smelters, Ontario, Canada.

Hyalella azteca (Crustacea: Amphipoda), water and sediments from 12 circum-neutral lakes between Sudbury and North Bay in Ontario, Canada were sampled in August 1998 and analyzed for 10 metals including Cu, Zn, Cd, Ni, Pb, Co, Mo, V, Ba and Ti. Statistical analyses showed that concentrations of the metals in H. azteca, water and sediment differed significantly (ANOVA, P<0.05) among lakes (except for Zn and Pb in H. azteca and Mo in water). There was a trend of declining metal concentration, especially for Cu, Ni and Co (in water, Hyalella and sediment), with distance from the smelters indicating the reduced impact of atmospheric pollution. Metal concentrations of lakes (water) in the Sudbury area were found to be lower compared to data from the 1970s and 1980s indicating an improvement in water quality. Metal concentrations in field-collected amphipods compared favorably with those measured in the laboratory in animals exposed to deep-water sediments, provided metal concentrations were not extremely low (e.g., Pb) and that water chemistry differences (e.g., pH) were taken into account for some metals (especially Cd). In general bioaccumulation of metals in H. azteca was predicted better from surface water than from sediment total metal.

Saturation models of arsenic, cobalt, chromium and manganese bioaccumulation by Hyalella azteca.

Bioaccumulation of As, Co, Cr and Mn by the benthic amphipod Hyalella azteca in Burlington City tap (Lake Ontario) water was measured in 4-week tests. Bioaccumulation increased with exposure concentration and demonstrated an excellent fit to a saturation model (r(2): 0.819, 0.838, 0.895 and 0.964 for As, Co, Cr and Mn, respectively). The proportion of total body Mn eliminated during a 24-h depuration period decreased as Mn body concentration increased, apparently due to a saturation of the elimination rate. The high maximum body concentration of 116,000 nmol g(-1) appears to result from the saturation of the Mn excretion which is slightly greater than the maximum Mn uptake rate. Elimination rates for As, Co and Cr were not dependent on body concentration. The four elements were not physiologically regulated in Hyalella. Their body concentrations should be good indicators of bioavailability and useful for environmental assessment.

Re-evaluation of metal bioaccumulation and chronic toxicity in Hyalella azteca using saturation curves and the biotic ligand model.

Bioaccumulation by Hyalella of all metals studied so far in our laboratory was re-evaluated to determine if the data could be explained satisfactorily using saturation models. Saturation kinetics are predicted by the biotic ligand model (BLM), now widely used in modelling acute toxicity, and are a pre-requisite if the BLM is to be applied to chronic toxicity. Saturation models provided a good fit to all the data. Since these are mechanistically based, they provide additional insights into metal accumulation mechanisms not immediately apparent when using allometric models. For example, maximum Cd accumulation is dependent on the hardness of the water to which Hyalella are acclimated. The BLM may need to be modified when applied to chronic toxicity. Use of saturation models for bioaccumulation, however, also necessitates the need for using saturation models for dose-response relationships in order to produce unambiguous estimates of LC50 values based on water and body concentrations. This affects predictions of toxicity at very low metal concentrations and results in lower predicted toxicity of mixtures when many metals are present at low concentrations.

New developments in the treatment of hypoplastic left heart syndrome.

Hypoplastic left heart syndrome (HLHS) was once a uniformly fatal disease, accounting the majority of neonatal deaths due to congenital heart defects. Twenty-five years of advances in the surgical and medical management of this disease have resulted in dramatic improvements in survival for these children. The goal for patients with HLHS should be survival of near 100% with a good quality of life. The advances described in this manuscript detail some of the new techniques used in the surgical and medical management. For infants undergoing staged reconstruction, the Norwood procedure is performed in the newborn period, followed by a hemi-Fontan operation at 6 months of age, and a modified Fontan operation at 1 to 2 years of age. A significant recent modification of the Norwood procedure is the placement of a right ventricle to pulmonary artery (RV-PA) conduit instead of a systemic artery to pulmonary shunt (modified Blalock-Taussig or BT shunt) as the source of pulmonary blood flow. Our recent experience with this modification demonstrated an incremental increase in survival, improved postoperative stability, and decreased inter-stage mortality. At catheterization, significant differences in hemodynamic parameters were present that were consistent with improved coronary blood flow, decreased volume load to the single right ventricle, and improved pulmonary artery growth in those patients with the RV-PA conduit. The 3rd stage in the surgical treatment of HLHS is the modified Fontan operation or cavo-pulmonary anastamosis. A new approach for Fontan completion is the placement of a stent covered with a thin layer of Goretex from the inferior vena cava to the hemi-Fontan baffle. This can be performed in the catheterization laboratory, with a decrease in post-procedure pleural effusions, lower mortality, and a shorter length of stay. The future of treatment for HLHS may eventually involve a single open-heart procedure with initial and final interventions being performed in the catheterization laboratory. Some cardiac centers perform transplantation for management of HLHS. Survival following transplantation has improved as advances in the pre- and post-operative management continue, along with new options for immunosuppression. Treatment for HLHS continues to evolve, as ongoing work has resulted in improved short and long-term survival. The future for children with this disease is encouraging as evidenced by the remarkable achievements made to date and the current worldwide interest and study of HLHS.

Metal bioavailability and toxicity through a sediment core.

Sediment cores from Richard Lake near Sudbury, Ontario, were sectioned and analyzed for total metal content, plus metal bioavailability and toxicity to Hyalella azteca (after equilibration with oxygenated overlying water). Strong and similar sediment profiles were observed for Cd, Co, Cu and Ni in the sediment. However, these differed from metal bioavailability profiles (bioaccumulation by Hyalella and metals in overlying water). Bioavailability profiles for Cu also differed from those for Cd, Co or Ni. The deepest sediment layers, deposited prior to industrial development, were non-toxic. Sediment toxicity was attributed to Ni dissolution into overlying water. Moreover, differential bioavailability of Ni in surface and deeper sediment layers was observed. This can affect the interpretation of toxicity data for sediments collected by different methods (e.g. core vs. grab samples). Based on Pb-210 dating and trends in Ni in the core, chronic toxicity of surface sediments from Richard Lake might approach non-toxic levels in about 15 years.

Reducing conduct problems among children of battered women.

This study was an experimental evaluation of an intervention designed to reduce conduct problems among children of battered women. Participants were 36 families (mothers and children) in which the mother had sought shelter because of relationship violence and had at least 1 child (4-9 years old) with clinical levels of conduct problems. The intervention consisted of 2 primary components: (a) providing instrumental and emotional support and (b) teaching child management skills to mothers. Families were randomly assigned to either the intervention condition or the existing services comparison condition and were assessed on 5 occasions over 16 months after shelter departure. Compared with families receiving existing services, children in the intervention condition improved at a faster rate, the proportion of children displaying clinical levels of conduct problems was greatly diminished, and mothers displayed greater improvements in child management skills.

Allopurinol neurocardiac protection trial in infants undergoing heart surgery using deep hypothermic circulatory arrest.

OBJECTIVE: This pharmacologic protection trial was conducted to test the hypothesis that allopurinol, a scavenger and inhibitor of oxygen free radical production, could reduce death, seizures, coma, and cardiac events in infants who underwent heart surgery using deep hypothermic circulatory arrest (DHCA). DESIGN: This was a single center, randomized, placebo-controlled, blinded trial of allopurinol in infant heart surgery using DHCA. Enrolled infants were stratified as having hypoplastic left heart syndrome (HLHS) and all other forms of congenital heart disease (non-HLHS). Drug was administered before, during, and after surgery. Adverse events and the clinical efficacy endpoints death, seizures, coma, and cardiac events were monitored until infants were discharged from the intensive care unit or 6 weeks, whichever came first. RESULTS: Between July 1992 and September 1997, 350 infants were enrolled and 348 subsequently randomized. A total of 318 infants (131 HLHS and 187 non-HLHS) underwent heart surgery using DHCA. There was a nonsignificant treatment effect for the primary efficacy endpoint analysis (death, seizures, and coma), which was consistent over the 2 strata. The addition of cardiac events to the primary endpoint resulted in a lack of consistency of treatment effect over strata, with the allopurinol treatment group experiencing fewer events (38% vs 60%) in the entire HLHS stratum, compared with the non-HLHS stratum (30% vs 27%). In HLHS surgical survivors, 40 of 47 (85%) allopurinol-treated infants did not experience any endpoint event, compared with 27 of 49 (55%) controls. There were fewer seizures-only and cardiac-only events in the allopurinol versus placebo groups. Allopurinol did not reduce efficacy endpoint events in non-HLHS infants. Treated and control infants did not differ in adverse events. CONCLUSIONS: Allopurinol provided significant neurocardiac protection in higher-risk HLHS infants who underwent cardiac surgery using DHCA. No benefits were demonstrated in lower risk, non-HLHS infants, and no significant adverse events were associated with allopurinol treatment.congenital heart defects, hypoplastic left heart syndrome, induced hypothermia, ischemia-reperfusion injury, neuroprotective agents, allopurinol, xanthine oxidase, free radicals, seizures, coma.

Reduction in levels of triiodothyronine following the first stage of the Norwood reconstruction for hypoplastic left heart syndrome.

OBJECTIVE: Thyroid hormone has important effects on cardiovascular performance. This study was performed to evaluate the changes in levels of triiodothyronine following the first stage of reconstruction for hypoplastic left heart syndrome. METHODS: We enrolled 14 newborns with hypoplastic left heart syndrome scheduled for first stage reconstruction. Blood samples were obtained pre-, intra-, and post-operatively. Levels of free and total triiodothyronine were determined by radioimmunoassay. Statistical comparison was performed using Wilcoxon's signed rank test. RESULTS: The levels of free triiodothyronine decreased from a baseline of 355+/-31 pg/dl to 205+/-21 pg/dl upon the institution of bypass, and declined to a level of 135+/-9 pg/dl at 24 hours postoperatively. Similarly, levels of total triiodothyronine decreased from 101+/-15 ng/dl to 65+/-4 ng/dl upon the institution of bypass, and continued to decline during the first 24 hours postoperatively. Levels of free and total triiodothyronine had returned to baseline by the fifth postoperative day. CONCLUSIONS: The data demonstrate significant decreases in levels of free and total triiodothyronine during the early postoperative period. These changes in levels of thyroid hormone may have adverse effects on cardiac function during this phase of recovery.

Is there a role for extracorporeal life support after stage I Norwood?

OBJECTIVES: Controversy still surrounds the use of extracorporeal life support (ECLS) in patients with single ventricle physiology. An analysis of the experience with a group of neonates who underwent stage I Norwood palliation and received ECLS is reported. METHODS: A retrospective review of hospital records, operative notes and perfusion data was performed in a group of 12 consecutive patients undergoing ECLS in the perioperative period after stage I. An analysis to identify risk factors for poor outcome was performed. RESULTS: The mean age and weight were 3.9 days (1-14) and 2.6 kg (1.4-3.8), respectively. There were 3/12 patients under 2.5 kg and four patients were under 35 weeks of gestation. The most common diagnosis (7/12) was hypoplastic left heart syndrome with aortic atresia. Associated extracardiac anomalies were present in four patients. Three patients had an additional cardiac defect and two of these required an additional surgical procedure besides the stage I Norwood. The mean circulatory arrest was 56 min (46-63). ECLS was initiated preoperatively in one, intraoperatively in nine, and postoperatively in two patients. The indication for support was: arrhythmia (one), low output (six), cardiac arrest (three), unbalanced circulation (one), and hypoxemia (two). The mean duration of support was 68 h (24-192). Eight patients were weaned off support, and six were discharged home in good condition. Morbidity included sepsis in five, renal failure in five, neurologic sequelae in three, and bleeding in two. Prematurity, renal dysfunction and the initiation of ECLS outside the operating room were significantly associated with poor outcome. Residual hemodynamic effect, low birth weight and neurologic event showed a tendency towards poor outcome, but did not reach statistical significance. CONCLUSIONS: Although the use of ECLS in patients with single ventricle physiology still carries a significant risk, prompt initiation of support can improve the outcome in a group of patients with impaired cardiopulmonary function after stage I palliation.

Quantification of bioavailable nickel in sediments and toxic thresholds to Hyalella azteca.

Bioaccumulation and chronic toxicity of nickel (Ni) to Hyalella azteca in Ni-spiked sediments was strongly affected by the source of sediment used. The total range in LC50s on a sediment concentration basis ranged over 20 fold. Differences in Ni toxicity generally matched differences in Ni bioaccumulation, and toxicity expressed on a body concentration basis varied less than three fold. Body concentrations, therefore, provide a much more reliable prediction of Ni toxicity in sediments than do concentrations in the sediment. Ni in overlying water was also a reliable predictor of Ni toxicity, but only in tests conducted in Imhoff settling cones with large (67:1) water to sediment ratios. Overlying water LC50s for tests in beakers varied 18 fold. Sediment and body concentrations of Ni tolerated by Hyalella were slightly higher in cones than in beakers. Reproduction was not affected significantly by Ni at concentrations below the LC50 and 10-week EC50s for survival and biomass production (including survival, growth and reproduction) were only marginally lower than 4-week EC50s (survival and growth only).

Laparoscopic colon resections: a five-year retrospective review.

In recent years, laparoscopic surgery has become a matter of growing interest. It has been shown that laparoscopic colectomy is well tolerated and safe for benign disease. However, there is some uncertainty about using this method for malignant disease when curative resection is the aim. These uncertainties mainly consist of spread of cancer to port site, long-term survival, and adequacy of resection. The majority of laparoscopic colectomies are technically assisted procedures in which anastomosis is performed outside the abdomen. However, some surgeons are now performing this surgery totally laparoscopically with the anastomosis performed inside the abdomen. Laparoscopic colectomy is currently practiced with great frequency by general surgeons. Its performance requires a steep learning curve and a large number of cases to obtain proficiency. The indications for laparoscopic colectomy are different from one institution to another. In some institutions all patients with colorectal disease are candidates for laparoscopic colectomy and in others it may be limited to benign disease only. The purpose of this review is to analyze all laparoscopic colectomies performed at our medical center since 1992. We conducted a retrospective chart review of both hospital and clinic charts of patients who underwent colectomies at our hospital. A total of 338 patient charts were reviewed. In a comparison of both laparoscopic (n = 285) and converted (n = 53) methods, the age and operative time were about the same. Age average and operating room time average were similar for both groups. With laparoscopy, there was a 3-day drop in length of hospital stay as well as a 1-day-earlier regaining of bowel function. Hospital cost dropped 5000 dollars average for the laparoscopic colectomy. The conversion rate at our center was 15 per cent. Complication rates were lower in the laparoscopic group. Recurrence of cancer at the port site (0.7%) was no higher than in the converted group (incisional recurrence, 1.8%). We conclude that laparoscopic colectomy does show an improvement in return of bowel function, hospital cost, and shorter hospital stay. Long-term follow-up will be necessary to determine the effectiveness of laparoscopic colon resection for colorectal cancer.

Patterns of adjustment among children of battered women.

Children exposed to interparental violence have been characterized by an array of psychological problems, but findings regarding the precise nature of these problems have been inconsistent. This study used cluster analysis to determine whether distinct patterns of adjustment could be identified in 228 8- to 14-year-old children residing in battered women's shelters. Five such patterns emerged: multiproblem-externalizing, multiproblem-internalizing, externalizing, mild distress, and no problems reported. This solution was cross-validated in independent halves of the sample and was similar for boys and girls. Differences among the clusters on relevant family and demographic variables were examined, and it was found that the clusters could be distinguished on the basis of the frequency of children's exposure to interparental violence, parent-child aggression, and children's appraisals of interparental conflict.