[Artificial intelligence in orthopedics and trauma surgery]. / Künstliche Intelligenz in der Orthopädie und Unfallchirurgie.

Artificial intelligence (AI) is a very relevant topic for the medicine of the future. This article focuses on the field of AI in the context of orthopedics and trauma surgery. The main focus is on the potentials of AI in the analysis of symptoms, radiological images, clinical data sets, use in hospitals and operating theaters as well as for training and education. For the orthopedics and trauma surgery of the future AI is much more than pure fiction; however, there is still a long way to go before the potential of an optimized and individualized patient care can be utilized. Interdisciplinary and international approaches, including personnel, economic, legal and ethical aspects will play a decisive role in this respect.

[Staff Satisfaction within Duty Hour Models: Longitudinal Survey on Suitability and Legal Conformity at a Surgical Maximum Care Department]. / Mitarbeiterzufriedenheit im Arbeitszeitmodell: Längsschnittstudie zu Praxistauglichkeit und Gesetzeskonformität in einer chirurgischen Klinik der Maximalversorgung.

Background Between the conflicting requirements of clinic organisation, the European Working Time Directive, patient safety, an increasing lack of junior staff, and competitiveness, the development of ideal duty hour models is vital to ensure maximum quality of care within the legal requirements. To achieve this, it is useful to evaluate the actual effects of duty hour models on staff satisfaction. Materials and Methods After the traditional 24-hour duty shift was given up in a surgical maximum care centre in 2007, an 18-hour duty shift was implemented, followed by a 12-hour shift in 2008, to improve handovers and reduce loss of information. The effects on work organisation, quality of life and salary were analysed in an anonymous survey in 2008. The staff survey was repeated in 2014. Results With a response rate of 95% of questionnaires in 2008 and a 93% response rate in 2014, the 12-hour duty model received negative ratings due to its high duty frequency and subsequent social strain. Also the physical strain and chronic tiredness were rated as most severe in the 12-hour rota. The 18-hour duty shift was the model of choice amongst staff. The 24-hour duty model was rated as the best compromise between the requirements of work organisation and staff satisfaction, and therefore this duty model was adapted accordingly in 2015. Conclusion The essential basis of a surgical department is a duty hour model suited to the requirements of work organisation, the Working Time Directive and the needs of the surgical staff. A 12-hour duty model can be ideal for work organisation, but only if augmented with an adequate number of staff members, the implementation of this model is possible without the frequency of 12-hour shifts being too high associated with strain on surgical staff and a perceived deterioration of quality of life. A staff survey should be performed on a regular basis to assess the actual effects of duty hour models and enable further optimisation. The much criticised 24-hour duty model seems to be much better than its reputation, if augmented by additional staff members in the evening hours.

Have We Hatched the Addiction Egg: Reward Deficiency Syndrome Solution System™

This article co-authored by a number of scientists, ASAM physicians, clinicians, treatment center owners, geneticists, neurobiologists, psychologists, social workers, criminologists, nurses, nutritionist, and students, is dedicated to all the people who have lost loved ones in substance-abuse and "reward deficiency syndrome" related tragedies. Why are we failing at reducing the incidence of 'Bad Behaviors'? Are we aiming at the wrong treatment targets for behavioral disorders? We are proposing a paradigm shift and calling it "Reward Deficiency Solution System" providing evidence for its adoption.

Low and Normal IGF-1 Levels in Patients with Chronic Medical Disorders (CMD) is Independent of Anterior Pituitary Hormone Deficiencies: Implications for Treating IGF-1 Abnormal Deficiencies with CMD.

Over time, based on evidence-based medicine, a number of hormonal test levels including IGF-1 had been raised or lowered to meet new criteria standards. In particular, IGF-1 plasma levels have been shown in several studies to be an independent diagnostic tool in Adult Growth Hormone Deficiency (AGHD). Many endocrinology studies link low IGF-1 plasma levels with low levels of other anterior pituitary hormones (i.e., LH, FSH, and TSH). Low IGF-1 is considered by most to be between 84-100 µ/l and numerous studies recommend that raising IGF-1 to high normal range reverses Chronic Medical Diseases (CMD), improves bone mineral density (BMD), and fibromyalgia. Moreover, some studies suggest that low levels of IGF-1 by itself independent of anterior pituitary deficiencies is sufficient to determine AGHD in humans. In order to determine the relationship of low IGF-1 with that of LH, FSH, and TSH levels in subjects with CMD, we evaluated these levels (± SD) in 944 patients. Patients with IGF-1 below 84 µ/l, 100 µ/l, and 150 µ/l were accessed. 9.22% had less than 84 µ/l (SD ± 12.52); 19.9% had less than 100 µ/l (SD ± 9.54); and 51.6 had less than 150 µ/l (SD ± 26.0). Specifically, the percentages found for low LH, FSH, and TSH were only 4.2%, 4.8%, and 6.5%. We conclude that IGF-1 deficiencies occur independent of comorbid deficiencies of LH, FSH, and TSH. Finally, we propose that based on the present investigation, IGF-1 low levels between the range of 84-100 µ/l may be too low to be considered as an independent diagnostic marker to treat AGHD with CMD.

Results of surgical and somatostatin analog therapies and their combination in acromegaly: a retrospective analysis of the German Acromegaly Register.

BACKGROUND: Data on surgical and medical treatment outcomes in acromegaly mostly originate from specialized centers. We retrospectively analyzed the data on surgery, primary somatostatin analog (SSA) therapy, surgery preceded by SSA, and SSA preceded by surgery in 1485 patients from the German Acromegaly Register. METHODS: Two trained nurses visited all centers (N=42) for data acquisition. RESULTS: Primary surgery: out of 889 patients, 554 yielded analyzable data (microadenomas 22.9%, macroadenomas 77.1%). GH and IGF1 normalized in 54.3 and 67.2%. Partial or total pituitary insufficiency occurred in 28.6% initially and 41.2% post-surgery. Primary SSA (>or=3 months): out of 329 patients, 145 yielded analyzable data (microadenomas 26.7%, macroadenomas 73.3%). GH and IGF1 normalized in 36.3 and 30.5%, increasing to 40.8 and 41.5% with longer SSA (>or=360 days) in 54 patients. Pituitary function did not change. SSA (>or=3 months) prior to surgery: out of 234 patients, 93 yielded analyzable data. Post-surgery GH and IGF1 was normalized in 62.9 and 68.4%. GH improvement was slightly, but significantly better after SSA pretreatment. Surgery followed by SSA: out of 122 patients, 34 yielded analyzable data. GH and IGF1 normalized during SSA in 24.1 and 45.5%. Relative GH decrease was significantly larger compared with primary SSA. CONCLUSIONS: Pituitary surgery was more effective to lower GH and IGF1 concentrations than primary SSA. Primary SSA may be an option in selected patients. SSA prior to surgery only marginally improved surgical outcome. Debulking surgery may result in better final outcome in patients with a high GH concentration and a large tumor.

[A method for reassessment of cost-intensive cases in visceral surgery. Results of project by the German Society for Visceral Surgery]. / Methode zur Abbildung kostenintensiver Fälle in der Viszeralchirurgie. Ergebnisse des DRG-Projekts der Deutschen Gesellschaft für Viszeralchirurgie.

Since the introduction of diagnosis-related groups (DRGs) many surgical departments report inappropriate reimbursement for complex cases and a shift in costly cases. To evaluate this situation, the German Society for Visceral Surgery inaugurated the present cost calculation project. In three university hospitals for 50 cases each, we depicted possible cost separators and utilized the complete cost calculation data (so-called Paragraph 21 data set) to test these separators. We identified "admission from another hospital", "severe surgically relevant concomitant disease", and "reoperation during the same hospital admission". The last was considered the economically most significant and medically most valid factor and was submitted as a possible modification to the german DRG system. The proposed cost separator "reoperation during the same hospital admission" was introduced into the DRG system after validation and leads to better allocation of reimbursements to complex and costly cases.

[Epidemiology and perspectives in traumatology of the elderly]. / Epidemiologie und Perspektiven der Alterstraumatologie.

Corresponding to the demographic development, fractures of the humerus, wrist, or hip will occur noticeably more often during the next four decades. The number of patients with hip fractures will increase to 170% of present-day numbers, and in the age group >80 years to 250%. Trauma surgical departments should train their staff as well as adapt their workflows and ambient conditions to this demanding clientele to be prepared for these changes. For the elderly, a fracture may lead to need for permanent home care, which is why postoperative transfer to ambulatory care is especially important. The expected cost progression in traumatology of the elderly may be moderated by the conjunction of inpatient and ambulatory care, the utilization of synergies among the different service types, and by implementation of prophylaxis for osteoporosis and falls.

[Proximal femoral fractures in the elderly. Data from health insurance providers on more than 23 million insured persons--part 2]. / Proximale Femurfrakturen im Alter. Krankenkassendaten von über 23 Mio. Versicherten--Teil 2.

BACKGROUND: The section of geriatric trauma ("AG-Alterstraumatologie") of the"Deutsche Gesellschaft für Unfallchirurgie" (DGU) and the"Lohmann & Birkner Health Care Consulting GmbH" in co-operation with the health insurance funds (VdAK and AEV) supplied the relevant data of approximately 23 million insured persons from the years 2002 to 2004. All data from patients over the age of 60 staying in hospital because of proximal femur fractures and without further injuries as the main diagnosis were extracted from the available amount of data and then analysed. RESULTS: In comparison to the effective number of beds there was a significant increase in the treatment of proximal femur fractures in hospitals with 101-300 beds. There was no difference in the operative treatment of proximal femur fractures in comparison to the number of beds of the hospital. The average hospital expense for osteosynthesis was 6000 euro per each case and there was no difference in comparison to the different osteosynthetic procedures. The average hospital expense for hip replacement (7036-7201 euro) was about 1000 euro higher than osteosynthetic procedures. There was no difference in the average hospital expense in comparison to the age of the patients. CONCLUSION: There was a significant age-dependent increase of acute hospital mortality with a maximum of 8.6% in the group of the patients older than 85 years. As a result of the demographic change fracture rates in the elderly population will rise significantly.

[Proximal femoral fractures in the elderly. Analysis of data from health insurance providers on more than 23 million insured persons--part 1]. / Proximale Femurfrakturen im Alter. Auswertung von Krankenkassendaten von über 23 Mio. Versicherten--Teil 1.

BACKGROUND: The section of geriatric trauma ("AG-Alterstraumatologie") of the "Deutsche Gesellschaft für Unfallchirurgie" (DGU) and the "Lohmann & Birkner Health Care Consulting GmbH" in co-operation with the health insurance funds (VdAK and AEV) supplied the relevant data of approximately 23 million insured persons from the years 2002 to 2004. METHODS: All data from patients over the age of 60 staying in hospital because of proximal femur fractures and without further injuries as the main diagnosis were extracted from the available amount of data and then analysed. There were 68,929 (9.5%) cases diagnosed with proximal femur fractures of 724,606 patients treated in hospital. RESULTS: There was a significant age-dependent increase in incidents of proximal femur fractures with a maximum of 3,000 injuries around the age of 82 years. The surgical treatment of proximal femur fractures was carried out with a joint-preserving stabilising method (osteosynthesis-screws-"DHS"-nailing systems) in 49.5%, with endoprosthesis in 48.6 % as well as other methods in 1.9% of the cases. In comparison to hip replacement care, a shorter hospital stay could be proved with osteosynthetic methods.

Clinical significance of the RT-PCR positive sentinel node in melanoma.

BACKGROUND: The clinical relevance of RT-PCR positivity for melanoma markers in the sentinel node remains controversial. Our purpose was to determine whether patients with a histologically negative but RT-PCR positive node were at an increased risk for recurrence than their RT-PCR negative counterparts. METHODS: Thirty-nine adult patients underwent sentinel node biopsies for melanoma between 1998 and 2000. Each sentinel node was bivalved. Half was serially sectioned and examined by routine hematoxylin and eosin (H&E) and immunohistochemistry (IHC; S100, HMB-45, melanA, and tyrosinase). The other half was analyzed by a nested RT-PCR assay for tyrosinase. RESULTS: Patients were followed for recurrence with a mean follow-up of 71.1 months. The odds ratio of recurrence for RT-PCR positive versus RT-PCR negative patients was 1.39 (0.34, 5.62; p = 0.73). Within the histology negative subgroups, the risk of recurrence in the RT-PCR positive group (26.7%) was not significantly different from the risk of recurrence in the RT-PCR negative group (22.2%) (p = 0.33 chi-squared). RT-PCR of the sentinel node was not a predictor for recurrence on multivariate analysis (p = 0.65). CONCLUSION: Sentinel node RT-PCR positivity did not risk stratify histologically negative melanoma patients beyond routine pathologic examination in this series.

The German Acromegaly Registry: description of the database and initial results.

UNLABELLED: Patient registries are valuable tools to study long-term morbidity and mortality of rare diseases. Acromegaly is rare (incidence 3-4/mill/year, prevalence 40-70/mill; approx. 300 new patients/yr and up to 5700 patients in Germany). Diagnostic and therapeutic possibilities have considerably improved, but treatment results remain often unsatisfactory. The main cause is residual disease activity after surgery, most importantly due to invasive macroadenomas. The German Acromegaly Registry is an initiative of the Pituitary Study Group of the German Endocrine Society (DGE). Formally established in January 2003 by the Board of the DGE, long-term financial support is guaranteed by an unrestricted grant from Novartis Pharma GmbH to the DGE. The registry cooperates closely with the United Kingdom and the Austrian registries. The aim of the German Acromegaly Registry is to establish a database of sufficient epidemiological strength in order to (1) document co-morbidity and mortality, (2) provide data on diagnostic and therapeutic procedures/effectiveness, (3) enable comparison of procedures in different national centres, (4) provide information for patient support groups/interaction with health care providers, (5) enable comparison with other national registries within Europe. The registry has at present 82 participating centres, and 42 have included patients (20 university clinics, 8 non-university hospitals, 14 centres in private practice). The database aims to include all acromegalic patients in Germany who are cared for and treated at present. Up to December 2005 1543 patients have been entered in a retrospective manner. Data collection is by external monitoring by highly trained study nurses who visit the individual centres. Inclusion is planned to continue at a rate of 500 per year. Starting in 2005 centres are revisited every 3 years at a rate of 500 per year (prospective phase of the registry). Quality of the data has been validated by an independent monitoring team which demonstrated high data concordance. CONCLUSIONS: Initial results of the German Acromegaly Registry show that it was possible to include a large number of patients within 3 years into the registry. Data quality has been validated and shown to be satisfactory. Therefore, the registry will be a useful tool to study long-term morbidity and mortality in a large series of patients.

[Changes in the G-DRG System from 2003 to 2005 in Ophthalmology--Ophthalmologic G-DRG 2003 to 2005]. / Anderungen des G-DRG-Systems von 2003 bis 2005 in der Augenheilkunde -- Ophthalmologische G-DRGs von 2003 bis 2005.

BACKGROUND: The objective of the study was to illustrate the effect of the extensive changes of the German DRG System on reimbursement of clinical ophthalmology during the years 2003, 2004 and 2005. METHODS: All ophthalmologic patients treated as in-patients at the Department of Ophthalmology at the University Munich during the year 2003 served as a reference data basis. By means of appropriate software those cases were then re-grouped according to the G-DRG classification of the years 2003, 2004 and 2005. This resulted in different reimbursements caused only by system changes for an exemplary hospital of maximum medical care. In addition, the same calculations were performed for four virtual, typical clinics based on the calculation data of the "Institut für Entgeltsysteme (InEK)". For those four clinics it was assumed that 80 % of the cases came from one of the subspecialties retina, glaucoma, cataract or strabismus surgery. RESULTS: Changes in the G-DRG system caused the sample hospital of maximum care to loose 8.5 % case mix index (CMI) during the period of 2003 to 2005. For three of the four virtual, typical ophthalmological clinics the theoretic reimbursement conditions also deteriorated: retina surgery -- 10.6 %, glaucoma surgery - 15.8 % and cataract surgery -- 17.9 % CMI. Only strabismus surgery showed an increase of + 5.6 % in CMI during the period examined. CONCLUSION: Over the years 2003 to 2005 the CMI clearly deteriorated for many ophthalmological subspecialties given otherwise identical conditions. To calculate the changes specifically for an individual hospital, the individual base rates have to be considered.

Effect of activated recombinant human factor 7 (Niastase) on laboratory testing of inhibitors of factors VIII and IX.

Activated recombinant human factor VIIa (rFVIIa) has been used as a hemostatic agent in patients with hemophilia and acquired inhibitors. Other indications for rFVIIa may include liver disease, warfarin sodium (Coumadin) overdose, or trauma. Monitoring patients on this treatment with standard laboratory testing is problematic. Bleeding risk does not correlate well with the prothrombin time (PT) or the activated partial thromboplastin time (aPTT) during therapy with rFVIIa. In addition, there is no identifiable literature on the effect of rFVIIa on assays of inhibitors in this patient group. Monitoring inhibitors may be important during interventions aimed at acutely reducing inhibitor levels, such as during plasma exchange or protein adsorption. We performed factor assays and evaluated inhibitor levels in plasma from 3 patients with deficiencies in FVIII (2 patients) or FIX (1 patient) and inhibitors (titer range, 5.8-17.4 Bethesda units) before and after adding rFVIIa (range, 0.25-8 microg/mL) in vitro. Additionally, we performed assays of factors of both intrinsic and extrinsic systems to determine the impact of rFVIIa on these tests. We found that both factor levels and inhibitor titers from patients with hemophilia A or B could be measured accurately, even in the presence of suprapharmacologic doses of rFVIIa (8 microg/mL). We also obtained accurate measurements for other assays of the intrinsic coagulation system (FXI and FXII) based on the aPTT. Conversely, we found that assays of the extrinsic system based on the PT (FII, FV, and FX) produced results that were unreliable. FVII results were very high but reproducible. These results suggest that assays based on the PT are inaccurate and should be avoided during FVIIa treatment. Conversely, FVIII and FIX levels and inhibitor titers can be accurately monitored in hemophilia patients receiving rFVIIa according to results of aPTT-based coagulation tests.

Importance of black carbon to sorption of native PAHs, PCBs, and PCDDs in Boston and New York harbor sediments.

The solid-water distribution ratios (Kd values) of "native" PAHs, PCBs, and PCDDs in Boston and New York Harbor sediments were determined using small passive polyethylene samplers incubated for extended times in sediment-water suspensions. Observed solid-water distribution coefficients exceeded the corresponding f(oc)Koc products by 1-2 orders of magnitude. It was hypothesized that black carbon (fBC), measured in the Boston harbor sediment at about 0.6% and in the New York harbor sediment at about 0.3%, was responsible for the additional sorption. The overall partitioning was then attributed to absorption into the organic carbon and to adsorption onto the black carbon via Kd = f(oc)Koc + f(BC)K(BC)C(w)n-1 with Cw in microg/L. Predictions based on published Koc, K(BC), and n values for phenanthrene and pyrene showed good agreement with observed Kd,obs values. Thus, assuming this dual sorption model applied to the other native PAHs, PCBs, and PCDDs, black carbon-normalized adsorption coefficients, K(BC)S, were deduced forthese contaminants. Log K(BC) values correlated with sorbate hydrophobicity for PAHs in Boston harbor (log K(BC) approximately 0.83 log gamma w(sat) - 1.6; R2 = 0.99, N= 8). The inferred sorption to the sedimentary BC phase dominated the solid-water partitioning of these compound classes, and its inclusion in these sediments is necessary to make accurate estimates of the mobility and bioavailability of PAHs, PCBs, and PCDDs.

[Bavarian mammography screening: results of consistency tests in X-ray units over three months]. / Ergebnisse aus drei Monaten Konstanzprüfung an Röntgeneinrichtungen im Bayerischen Mammographie-Screening.

PURPOSE: To find out whether the quality requirements in daily, weekly or monthly tests of the "European protocol for the quality control of the physical and technical aspects of mammographic screening (EPQC)" can be maintained when screening the population of a large area. Furthermore, to check the specific tolerances of different test positions given by the EPQC for redundancy and statistical correlation. MATERIALS AND METHODS: Daily test images were obtained with an additional exposition of a sensitometric step wedge according DIN 6868 - 2. Weekly densitometry and visual inspection were performed at the University of Applied Sciences, Cologne. RESULTS: All units were able to maintain basic requirements on image quality as long as films of the same batch number were used. Some tolerance requirements of the EPQC are inconsistent and redundant. CONCLUSION: The occasionally considerable fluctuations of film processing require a daily check on the processing conditions. Daily test images of the units are only obligatory in the first 4 to 5 weeks of a new operation. All test results should be analyzed retrospectively in an independent test laboratory with emphasis on the statistical behavior of the unit. The tolerances prescribed by the EPQC are not always consistent and should be adapted to today's scientific standard when applied in mammography screening centers.

A randomized phase II study of two schedules of bryostatin-1 (NSC339555) in patients with advanced malignant melanoma: A National Cancer Institute of Canada Clinical Trials Group study.

PURPOSE: This study addressed the efficacy and toxicity of the novel compound Bryostatin-1 (NSC 339555), a novel agent with antineoplastic, hematopoietic and immunomodulatory activity in a variety of in vitro and in vivo systems. PATIENTS AND METHODS: This phase II study randomly assigned chemotherapy-naïve patients with untreated metastatic melanoma and measurable disease to two schedules of treatment: Arm A, 25 microg/m2 bryostatin-1 given as a 24 hour continuous infusion weekly or Arm B, 120 microg/m2 bryostatin-1 given as a 72 hour continuous infusion every 2 weeks. Although objective response was assessed using standard NCIC CTG criteria, antitumour activity was assessed using a multivariate endpoint incorporating both response (CR and PR) and early progression (PD at < or = 8 weeks). Seventeen patients were randomized to each arm. RESULTS: Arm A was better tolerated with 86.7% of 15 evaluable patients receiving > or = 90% of planned dose intensity versus 76.5% of 17 evaluable patients in Arm B. On Arm B, three patients experienced serious adverse events and three patients had to be removed from protocol therapy due to toxicity. The most common side effect was myalgia (33% grade 1-2 on Arm A versus 65% on Arm B with 5 patients experiencing grade 3 and one patient grade 4). Lethargy was more common on Arm A but more severe on Arm B. Other side effects such as nausea, diarrhea and headache were generally mild to moderate in nature and occurred with a similar frequency on both arms. Hematologic and biochemical toxicity were minimal. This trial was closed early because the protocol-stopping rule was met based on lack of required responses and on the number of early progressions on both arms. No partial or complete responses were seen; 3 patients randomized to Arm A had stable disease (duration 9-24 weeks) as did 4 patients (duration 10-38 weeks) randomized to Arm B. CONCLUSION: Arm A was better tolerated than Arm B. We conclude that bryostatin-1 has little efficacy in the treatment of metastatic melanoma with either of the schedules studied.

Atmospheric distribution of polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs), and non-ortho biphenyls (PCBs) along a North-South Atlantic transect.

Air samples were taken on board the RRS Bransfield (typically for 24-72 h), during an Atlantic cruise from the U.K. to Antarctica in October-December 1998, to investigate the global scale distribution of PCDD/Fs and coplanar PCBs. Highest concentrations of Cl2-8DD/Fs all occurred between 25 and 52 degrees N; lowest concentrations were measured around approximately 60 degrees S and further south. Cl3DFs showed highest overall concentrations (up to 9800 fg/m3), followed by Cl2DFs (up to 5300 fg/m3) and OCDD (up to 1300 fg/m3). Lowest concentrations, measured in the remote Southern hemisphere, were generally 2 orders of magnitude lower than their highest concentrations over the North Atlantic. Concentrations of PCB-77 were higher in the northern hemisphere, while PCB-126 and PCB-169 exhibited highest concentrations around the equator. Evidence was obtained for substantial emissions of PCDD/Fs off west Africa and while in the port of Montevideo, Uruguay. Shifts in PCDD/F profile distribution were observed on increasing distance from source regions, such that those from the most remote locations were dominated by Cl3DF (approximately 40% of the total) and OCDD (approximately 20%). Gas-particle partition data was obtained for all samples. Cl4-6DD/Fs showed the widest range, varying between 10 and 90% of the total in the gas phase, depending on location/ temperature. The study gave limited evidence for the influence of OH-radical initiated depletion reactions of gaseous PCDD/Fs. The global atmospheric burden is estimated to be on the order of 350 kg sigmaCl4-8DD/Fs and approximately 3 kg sigmaTEQ.

The significance of PCBs in the atmosphere of the southern hemisphere.

Air monitoring stations were set up at 2 sites in the southern hemisphere--Moody Brook, Falkland Island (51 degrees 25' S, 57 degrees 56' W) and Halley, Research Station, Antarctica (75 degrees 35' S, 26 degrees 30' W). PCBs were monitored at the stations throughout 1999. Highest concentrations were observed when temperatures were greater. In general, concentrations were greater at Moody Brook than at Halley, although the difference in concentrations between sites was less for more chlorinated congeners. Air concentrations at both sites were compared with samples collected nearby over-water. Over water air concentrations were found to be greater than over land air concentrations. Concentrations were also compared with literature data for air concentrations at a remote site in the Canadian Arctic. Atmospheric concentrations of tri-chlorinated biphenyls were found to be approximately double those reported for Ellesmere Island in the Canadian Arctic, whilst concentrations in samples from Antarctica were very similar to those found in the high Arctic. Most other PCBs were a factor of 2-4 greater in the Canadian Arctic.

Further developments in the use of semipermeable membrane devices (SPMDs) as passive air samplers for persistent organic pollutants: field application in a spatial survey of PCDD/Fs and PAHs.

Semipermeable membrane devices (SPMDs) were deployed at 19 sites in northwest England to test their efficacy as passive atmospheric samplers for polychlorinated dibenzo-p-dioxins and -furans (PCDD/Fs) and polycyclic aromatic hydrocarbons (PAHs). SPMDs were found to be efficient samplers for vapor phase species in the atmosphere, with good reproducibility between samplers. Species which are partially or completely particle associated under ambient U.K. conditions were also sampled by the SPMDs but with poorer reproducibility. It is suggested that SPMDs could be used to indicate "hotspots" of particulate associated species, however. Differences in absolute and relative concentrations of all PCDD/Fs and PAHs sequestered bythe SPMDs were observed between sites. High amounts were sequestered in SPMDs at sites where previous active monitoring has indicated relatively high atmospheric concentrations, confirming the potential of SPMDs as a tool for semiquantitative spatial monitoring of atmospheric species. SPMDs also respond to differences in the mixture of compounds present in the atmosphere, thereby aiding source apportionment studies.