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In the field of severe asthma, the concept of disease control has recently been integrated by the one of clinical remission. With this new concept, we move on to analyze the efficacy of therapy on multiple parameters simultaneously, starting with the mandatory discontinuation of the systemic glucocorticoids, to which is added the effect on exacerbations, respiratory function, and symptoms control. The Italian severe asthma registry SANI (Severe Asthma Network Italy) drafted criteria for the definition of disease remission, allowing patients to be classified into two groups, partial and complete remission. The greater dynamism of the definition, provided by SANI, allows us to hypothesize its practical use, concerning therapy management of severe asthma patients, starting from the level of remission, with the aim to facilitate the clinical decision on replacement, continuation or modulation of patients' therapy.

Thymic stromal lymphopoietin (TSLP), is a protein belonging to a class of epithelial cytokines commonly called alarmins, which also includes IL-25 and IL-33. Functionally, TSLP is a key player in the immune response to environmental insults, initiating a number of downstream inflammatory pathways. TSLP performs its role by binding to a high-affinity heteromeric complex composed of the thymic stromal lymphopoietin receptor (TSLPR) chain and IL-7Rα. In recent years, the important role of proinflammatory cytokines in the etiopathogenesis of various chronic diseases such as asthma, chronic rhinosinusitis with nasal polyposis (CRSwNP), chronic obstructive pulmonary diseases (COPDs), and chronic spontaneous urticaria has been studied. Although alarmins have been found to be mainly implicated in the mechanisms of type 2 inflammation, studies on monoclonal antibodies against TSLP demonstrate partial efficacy even in patients whose inflammation is not definable as T2 and the so-called low T2. Tezepelumab is a human anti-TSLP antibody that prevents TSLP-TSLPR interactions. Several clinical trials are evaluating the safety and efficacy of Tezepelumab in various inflammatory disorders. In this review, we will highlight major recent advances in understanding the functional role of TSLP, its involvement in Th2-related diseases, and its suitability as a target for biological therapies.

Background: Benralizumab has been shown to restore good control of severe eosinophilic asthma (SEA). Robust data on benralizumab effectiveness over periods longer than 2 years are scarce. Methods: This retrospective multicentric study was conducted on 108 Italian SEA patients treated with benralizumab for up to 36 months. Partial and complete clinical remission (CR) were assessed. Data were analyzed with descriptive statistics or using linear, logistic, and negative binomial mixed-effect regression models. Results: At 36 months, benralizumab reduced the exacerbation rate by 89% and increased the forced expiratory volume in 1 second (FEV 1 ) (+440 mL at 36 months, p < 0.0001). Benralizumab improved asthma control as well as sinonasal symptoms in patients with chronic rhinosinusitis with nasal polyposis (CRSwNP). Up to 93.33% of patients either reduced or discontinued OCS; benralizumab also decreased ICS use and other asthma medications. Overall, 84.31% of patients achieved partial or complete CR. Conclusions: Benralizumab improved asthma and sinonasal outcomes up to 36 months. These findings support the potential of benralizumab to induce CR, emphasizing its role as a disease-modifying anti-asthmatic drug for the management of SEA. Further research is warranted to expand these findings by minimizing data loss and assessing benralizumab's long-term safety.

Background: In its severe form, where possible, asthma is treated using biological drugs in order to reduce, as much as possible, the use of systemic steroids. Mepolizumab is effective for severe asthma based on key outcomes such as exacerbation and steroid dependence. Its efficacy in terms of the criteria for clinical remission in the short and long term has become of interest., Objective: We aimed to evaluate the effect of mepolizumab in the achievement of clinical remission after 3 years of administration., Methods: In this study, 71 patients who continued mepolizumab for 3 years were assessed for clinical remission according to six different published sets of remission criteria., Results: According to the criteria, 39-52% of patients experienced complete remission in the first year, increasing to 51-73% at 3 years. By classifying patients according to partial and complete remission criteria, proposed by the SANI, we observe 22% of patients in partial remission at one year, achieving complete remission after three years. The baseline factors associated with earlier remission were a higher FEV1, if we consider classifications requiring an FEV1 ≥ 80%, a low OCS dose, and low FeNO levels, in the patients requiring FEV1 stabilization., Conclusions: Clinical remission is possible for patients treated with mepolizumab. The observations at three years compared with the first year indicated that the factors negatively affecting remission delayed rather than prevented it. Earlier treatment could increase the chances of remission.

Background: The small-airway dysfunction (SAD), detected with impulse oscillometry (IOS) methods, has been recently better characterized in patients with asthma. However, little is known about SAD in asthmatic patients with normal spirometry (NS)., Objective: In this study, we aimed to investigate, in an unselected sample of 321 patients with physician-diagnosed asthma and NS, prevalence, clinical characterization, and impact on asthma control of IOS-defined SAD. As a secondary objective of the study, we focused on comparing the difference between IOS- and spirometry-defined SAD., Methods: Consecutive patients with a previous diagnosis of asthma but normal spirometry at the moment of the enrollment were stratified by the presence of IOS-defined SAD (difference in resistance at 5 Hz and at 20 Hz [R5-R20] greater than 0.07 kPa x s x L -1 ). We have also assessed the presence of SAD defined by spirometry, according to FEF 25-75 < 65% of the predicted. Clinical and laboratory features were collected, and univariable and multivariable analyses were used to analyze cross-sectional associations between clinical variables and outcomes (SAD)., Results: IOS-defined SAD was present in 54.1% of the cohort. In contrast, spirometry-defined SAD was present in only 10% of patients. Subjects with IOS-defined SAD showed less well-controlled asthma and a higher mean inhaled corticosteroid dosage use compared with subjects without SAD (both P < .001). Overweight (odds ratio [OR], 1.14; 95% CI, 1.05-1.23), exacerbation history (OR, 3.06; 95% CI, 1.34-6.97), asthma-related night awakenings (OR, 6.88; 95% CI, 2.13-22.23), exercise-induced asthma symptoms (OR, 33.5; 95% CI, 9.51-117.8), and controlled asthma (OR, 0.22; 95% CI, 0.06-0.84) were independently associated with SAD., Conclusions: Asthmatic patients with IOS-defined SAD showed less well-controlled asthma, more severe exacerbations and higher mean inhaled corticosteroid dosage. We confirmed exercise-induced asthma, asthma-related night awakenings, exacerbation history, and overweight as independently associated with SAD, while showing well-controlled asthma as inversely associated. SAD may be overlooked by standard spirometry., Competing Interests: Declaration of competing interest All authors have no conflicts of interest to disclose about this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Limited physical access to health facilities contributes to inadequate medical care in low-income countries. Therefore, to fill the supply gap, the Indonesian government built limited-resource hospitals in impoverished areas. This study examines whether the existence of those hospitals improves medical care usage. Difference-in-differences adapted for continuous treatment methodologies was applied with exploitation of timing implementations of mobile hospital establishments. In the process, national representatives' survey data, hospital characteristics, and travel distance from various sources were used. Public hospitals' existence was discovered to cause substantial travel distance reduction, with outpatient and inpatient healthcare services becoming more accessible on the main islands compared with outer islands. On the basis of these results, expanding health facilities and improving infrastructures in poor regions broadly are essential for improving healthcare access., (Copyright © 2022 International Society for Health Economics and Outcomes Research. Published by Elsevier Inc. All rights reserved.)

This study provides baseline information on the concentrations of antibiotics in influent and effluent from two wastewater treatment plants in regular operation in the State of Kuwait. Wastewater samples were collected from the influent and effluent streams of two WWTPs, over four sampling campaigns and analyzed for a broad range of antibiotics. The mean influent concentrations of sulfamethoxazole, ciprofloxacin, clarithromycin, and cefalexin were 852 ng/L, 672 ng/L, 592 ng/L), and 491 ng/L, respectively, at Umm Al Hayman WWTP. At the Kabd WWTP, the influent concentration of clarithromycin was highest with a mean of 949 ng/L, followed by ciprofloxacin (mean, 865 ng/L), cefalexin (mean, 598 ng/L), and sulfamethoxazole (mean, 520 ng/L). The dominant compounds in the effluent from Umm Al Hayman were sulfamethoxazole (mean, 212 ng/L), ciprofloxacin (mean, 153 ng/L), ofloxacin (mean, 120 ng/L), dimetridazole (mean, 96 ng/L), and metronidazole (mean, 93 ng/L). Whereas, at the Kabd WWTP, the dominant compounds were sulfamethoxazole (mean, 338 ng/L), dimetridazole (mean, 274 ng/L), cefalexin (mean, 213 ng/L), ciprofloxacin (mean, 192 ng/L), and clarithromycin (189 ng/L). The mean influent concentrations of all compounds were higher than those measured in the effluents. The concentrations of antibiotic compounds were not significantly different between the two WWTPs (p > 0.05). The removal efficiencies of the various antibiotics over the four sampling campaigns for the Kabd and Umm Hayman WWTPs ranged between 10.87 and 99.75% and also showed that they were variable and were compound dependent. The data clearly show that the concentrations of antibiotics measured in the influents of both WWTPs were highest in samples collected during the winter-summer (September samples) transition followed by the concentrations measured during the winter-summer (March samples) transition period. This is possibly linked to the increased prescription of these medications to treat infectious diseases and flu prevalent in Kuwait during these periods. This study provides the first reported concentrations of antibiotics in the dissolved aqueous influents and effluents of WWTPs in Kuwait. Additional studies are required to evaluate the environmental impact that antibiotic residues may cause since treated wastewater is used in irrigation, and often there are instances when untreated wastewater is discharged directly into the marine environment.

This study provides an insight into the polychlorinated biphenyls (PCBs) inventories in the sediments of the northwestern Arabian/Persian Gulf. PCBs can be used as chemical markers that correlate with historical events in the region, to estimate the sedimentation rates in the northern Gulf, and to determine the sources of pollutants in the study area. The concentrations of PCBs were generally patchy in sediments. At Station 1 the ΣPCB concentrations generally fluctuated between 0.100 and 0.400 ng g -1 dw throughout the depositional history measured in a sediment core. There were four peaks in the ΣPCB profile corresponding to 1969, 1979, 1983 and 1991. Station 2 showed a prominent peak at depth of 25 cm. The concentrations of the ΣPCBs and ΣICE congeners at this depth were 28 and 12 ng g -1 dw respectively. Concentrations then dropped dramatically thereafter by a factor of 4. The ΣPCB concentrations at Station 3 were very low compared to the concentrations measured at Stations 1 and 2. The PCB concentration in Core 4 which was taken from open waters was 2-3 orders of magnitude lower than those in the other coastal cores. However, a 1990-91 peak was omnipresent in these cores. There is no record of PCB production within the Gulf region, and PCB releases into the Kuwait marine environment are likely to originate from their use in products. These maxima in early-1990s can be correlated to inputs from war-related activities, including the reported destruction of PCB-containing transformers and military equipment during the occupation of Kuwait. None of the recent sediment core sections at the four stations had a ΣPCB concentration near the effects range-median (ERM) concentration of 180 ng g -1 , or permissible exposure limits (PEL) of 189 ng g -1 , or were above the effect range-low (ERL) values of 22.7 ng g -1 ., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

This study was carried out to provide baseline information on the concentrations of pharmaceuticals in Kuwait's coastal waters. Samples were collected over four sampling campaigns from various outfalls that occasionally discharged water into the marine environment and analyzed for a range of pharmaceuticals including analgesic/anti-inflammatories, antibiotics, anticoagulant, antidiabetic, antihelmintics, antihypertensives, antiplatelet agent, asthma medication, β-blocking agent, calcium channel blocker, diuretic, histamine H1 and H2 receptor antagonist, lipid regulators/cholesterol-lowering, prostatic hyperplasia, psychiatric drug, sedation and muscle relaxant, synthetic glucocorticoid, tranquilizer and x-ray contrast media. The levels varied between the detection limits of the method and a maximum of 28,183 ng/L for analgesics/anti-inflammatories. The highest pharmaceutical concentrations were in samples collected during the September campaign, possibly linked to the increased prescription of these medications to treat infectious diseases and flu prevalent in Kuwait during the winter months. The spatial variation is concentration is evident with KISR site being most polluted as hospital wastewater is discharged at the site. This study provides the first dataset on the concentrations of pharmaceuticals in the seawater in Kuwait and possibly the wider Arabian Gulf. Kuwait's coastal water pharmaceutical concentrations derived from this study exceed those reported from the Spanish coast, the Hong Kong harbour, the Bohai and the Yellow seas. More studies are needed to evaluate the environmental impact that these residues may have on non-target organisms., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The development of safe and effective COVID-19 vaccines as well as their delivery to people's arms are the best hope for ending the COVID-19 pandemic. However, the implementation of vaccination varies greatly across countries, with the developing countries lagging behind. This study investigates Indonesia's vaccination experiences, challenges, and acceleration over the course of implementation period. This study provides simulations to estimate the vaccination rate using time-series forecasting machine learning. We use Administrative data and Survey results in our analysis. Our findings suggest limited vaccine availability had caused low-coverage vaccination implementation in the early stage of vaccination implementation period. However, following the increased availability of vaccine, the vaccination rate accelerates up to 600% times. The government of Indonesia utilized strategic public places, public and private offices, and engaging private sectors in the phase two implementation to accelerate the vaccination implementation. Indonesia might reach 63.1 million individuals vaccinated at the end of March 2022, or 35% of the targeted population with up to April 2021 vaccination rate. To accelerate, government introduced a number of new strategies including door-to-door persuasion through neighborhood association (RT), educating individuals, and providing transportation from their home to the vaccination facility. We expect new strategies could further improve vaccination speed by around 1.4 million to 3.5 million individuals per day.

The use of 210 Pb dating for the reconstruction of contaminant profiles in undisturbed sediments is the most widely acceptable technique historically. Due to the uncertainties associated with the technique, dating of sediments have often been supported by ancillary evidence such as an alternative historical marker in the catchment that is preserved in the sedimentary records. The most widely used verification marker is 137 Cs, which is attributed to global fallout from past nuclear weapons testing, and the Chernobyl accident. In the southern hemisphere, and the mid-latitudes, the 137 Cs signal from Chernobyl fallout is often absent from the sedimentary records making it very difficult to verify the 210 Pb chronologies in these natural archives. This study reports the spatial and temporal variability of total phosphorus (TP) and its forms in sediments from Kuwait Bay and provides evidence of the possibility of using Phosphorous as a potential marker to support dates derived from 210 Pb dating. In the current study we report the spatial and temporal variations in the concentrations of Phosphorus from near-shore sediments from Kuwait. The mean (and range) of TP concentration in surficial sediments is 19.4 (12.2 to 24) μmol-P g -1 dry weight. The highest concentrations were measured in the deepest portions of the Bay which is characterized by fine grained sediments. The vertical profile of TP in the sediments was characterized by a gradual increase in concentration from lower layers to a subsurface maximum (at approximately 4-5 cm) followed by an exponential decrease to the sediment-water interface. The sedimentary TP profile correlated remarkably well with changes in the population of Kuwait over the last three decades, suggesting that wastewater inputs into the Bay from treatment plants are an important source of phosphorus in the coastal waters. The decrease in concentration in sediment deposited over the last five years of the core is explained by the commissioning of an improved wastewater treatment plant with higher phosphorus removal efficiency. These fluctuations preserved in the sedimentary records linked to identifiable historical events provides powerful evidence that this nutrient associated with wastewater inputs in coastal aquatic environments can be used as ancillary information to support 210 Pb dating., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background and Aim of the Work: Every year around 275 thousand people in Europe and 420 thousand in the United States are affected by sudden cardiac arrest. Early electrical defibrillation before the arrival of emergency services can improve survival. Training the population to use the AED is essential. The training method currently in use is the BLSD course, which limits training to a population cohort and may not be enough to meet the requirements of the proposed Law no. 1839/2019. This study aims to verify the effectiveness of an online course that illustrates the practical use of the AED to a population of laypeople., Methods: An observational study was conducted to compare a lay population undergoing the view of a video spot and a cohort of people who had participated in BLSD Category A courses. The performances of the two groups were measured immediately after the course and 6 months later., Results: Overall, the video lesson reported positive results. Six months later the skills were partially retained. The cohort that followed the video lesson showed significant deterioration in the ability to correctly position the pads and in safety., Conclusions: Although improved through significant reinforcements, the video spot represents a valid alternative training method for spreading defibrillation with public access and could facilitate the culture of defibrillation as required by the new Italian law proposal.

A total of 20 organophosphate triesters (OPEs), including seven alkyl-OPEs, three chlorinated (Cl)-OPEs, seven aryl-OPEs, and three oligomeric-OPEs were measured in 341 house dust samples collected from 12 countries during the period 2010-2014. OPEs were ubiquitous in indoor dust, and the total concentrations of OPEs (∑OPEs; sum of 20 OPEs) ranged from 49.4 to 249,000 ng/g dry weight (dw). Generally, Cl-OPEs were the predominant compounds (51% of total) in indoor dust samples, with a median concentration of 800 ng/g, followed by alkyl-OPEs (31%), aryl-OPEs (17%), and oligomeric-OPEs (1%), with median concentrations of 480, 270, and 21.9 ng/g, respectively. ∑OPE concentrations in indoor dust from more industrialized countries (South Korea: median, 31,300; Japan: 29,800; and the United States: 26,500 ng/g dw) were one or two orders of magnitude higher than those from less industrialized countries (Greece: 7140, Saudi Arabia: 5310, Kuwait: 4420, Romania: 4110, Vietnam: 1190, China: 1120, Colombia: 374, India: 276, and Pakistan: 138 ng/g dw). Statistically significant positive correlations (0.114 < r < 0.748, p < 0.05) were found among the concentrations of 16 OPEs in dust samples, indicating similar sources of these compounds. The median estimated daily intakes of ΣOPEs via dust ingestion for children and adults were in the ranges of 0.29-64.8 and 0.07-14.9 ng/kg bw/day, respectively., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The study reports fortnightly atmospheric concentrations of organochlorine pesticides concomitantly measured at an urban, "industrial" and a remote location over a twelve month period in Kuwait to examine seasonal variability and urban-rural concentration gradients. The average±SD (and range) of the ΣOC concentrations measured throughout the study period in decreasing order were urban, 505±305 (range, 33-1352) pgm -3 , remote, 204±124 (4.5-556) pgm -3 , and "industrial" 155±103 (8.8-533) pgm -3 . The concentrations of most OCs measured in this study, except for DDT and its metabolites, were higher at urban locations relative to their concentrations at remote location, in line with the literature on POPs regarding urban conurbations being sources of industrial chemicals. The most abundant pesticides measured throughout this study were dieldrin, pentachlorobenzene, hexachlorobenzene, ΣDDTs, ΣHCHs, and oxychlordane. Hexachlorobenzene concentrations were generally higher than those of pentachlorobenzene and are both strongly negatively correlated with temperature (p<0.05) at all sampling locations. Mean summertime concentrations were higher for hexachlorocyclohexanes, chlordanes, dieldrin, and DDT isomers, except for pp-DDT. This may suggest that concentrations of these compounds may be driven by temperature., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background and Aim of the Work: The treatment of cardiac arrest in an extra-hospital environment improves with the increase in the number of people able to establish an early Cardio-Pulmonary Reanimation (CPR). The main aim of the study was to assess the validity of the two-step method in case of prolonged CPR., Methods: A randomized comparison study was conducted in the University Nursing School of a Northern Italian town, during the 2015/16 academic year, among 60 students, to teach them CPR techniques, through two different teaching methods (4-step and the 2-step of CPR training). The effectiveness of the maneuvers performed on mannequins equipped with skill-meter was verified., Results: Our study did not highlight any significant difference between the two methods of CPR training. The comparison between the two methods regarding their efficacy in practical teaching of CPR, highlighted by this study, proved the validity of both the 4-minute continuous method (1st method) and the 30:2 method (2nd method)., Conclusions: The results of the study showed no differences between the 2-step and the 4-step methods, in the effectiveness of cardiac massage. The correct execution of chest compressions during a CPR is the key to increase the patient's chances of rescue. Research has shown that any interruption in the execution of chest compressions, leads to a progressive reduction of the effectiveness of cardiac massage, with negative consequences on the prognosis of the patient undergoing at CPR.

The spatial and temporal variations in the atmospheric concentrations of PCBs were concomitantly measured at several sites over a twelve-month period in Kuwait to examine seasonal variability and urban-rural concentration gradients using two sampling methods. The annual mean (and range) of ∑PCB concentrations measured using high volume samplers was 10.8 (1.2-32) pg m -3 at the remote site and 39.4 (1.1-128) pg m -3 at the urban site. The median concentrations of ΣPCBs at the urban location (30.3 pg m -3 ) was significantly higher (p < 0.001) than that measured at the remote location (8.6 pg m -3 ) consistent with the view that urban centers are an important net source of these compounds to the environment. Passive sampler derived concentrations across the country showed a uniform distribution except at a few locations in the vicinity of suspected sources where elevated concentrations were measured. As with active sampling data, the concentrations measured using passive samplers were higher in urban areas (range, 4-78 pg/m 3 ) compared to remote sites (range, 2.2-17 pg/m 3 ). The concentrations measured at some urban sites correlated extremely well with mean temperature during the deployment period whereas temperature correlations with measured concentrations were negative at remote and semi-rural sites suggesting that air-surface exchange maybe a key driving mechanism of the current levels of PCBs in Kuwait., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

A sampling campaign was carried out to assess the impact of the oil field activities on the concentrations of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in ambient air at Umm Al-Aish oil field in northern Kuwait. Sixteen samples were collected from March 2014 to January 2015. The concentrations of ΣPCDD/Fs were relatively high (33.6-586 fg I-TEQ/m 3 ; median: 94.7 fg I-TEQ/m 3 ; 31.2 to 516 fg WHO-TEQ 2005 /m 3 ; median: 83.7 fg WHO-TEQ 2005 /m 3 ) compared to those of dl-PCBs (3.9-36.8 WHO-TEQ 2005 /m 3 ; median 9.9 WHO-TEQ 2005 /m 3 ). A unique PCDD/F profile that was not previously reported was found. Further investigations should be conducted to establish whether the dioxin profile found in this study is specific for the desulfurization facility located in the study area or from oil flaring in the oil fields located upstream of the study area. The findings suggest that the oil field activities have a significant impact on the PCDD/F concentration in ambient air but a low or negligible influence on dl-PCBs' levels., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The historical record of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) deposition was reconstructed from the analysis of a dated sediment core collected from a remote area in the northwestern Arabian Gulf not influenced by any point sources of contamination. The sedimentary record showed that PCDD/F concentrations started to increase above pre-industrial background levels in the mid-1960s. This was followed by an exponential increase in concentrations attaining a maximum of 7.5pg/g (dry wt) in the early 1980s and stayed fairly constant thereafter. The homolog profiles in sediments remained fairly consistent throughout the core with PCDD contributing 75% of the ΣPCDD/F concentrations. The homolog profile was dominated by OCDD which contributed approximately 55% of the total dioxins throughout the core. The consistency in the homolog patterns throughout the core suggests that the source of dioxins have remained fairly unchanged throughout the sedimentary record represented by the core., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Surficial sediment samples were collected from 25 locations within Kuwait Bay and outside the Bay, in the Northwestern Arabian Gulf, to access recent polycyclic aromatic hydrocarbon pollution in Kuwait. Time trends in the depositional history of PAHs to this portion of the Arabian Gulf was reconstructed from the analysis of a dated sediment core. Intersite differences in concentration exist although these differences were not statistically significant (p=0.08). However, organic carbon normalized concentrations within Kuwait Bay were 4 times higher than the average concentrations outside the Bay and were shown to be statistically significant (p<0.001). The sedimentary record showed that ΣPAHs concentration fluctuated between 12 and 25ngg -1 before 1970. Concentrations then increased sharply to a maximum of 45ngg -1 around the late 1970s and early 1980s followed by an exponential decrease in concentration to pre-1970 "background" concentrations of between 12 and 25ngg -1 ., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Synthetic phenolic antioxidants (SPAs), including 2,6-di-tert-butyl-4-hydroxytoluene (BHT), are extensively used in food, cosmetic and plastic industries. Nevertheless, limited information is available on human exposures, other than the dietary sources, to SPAs. In this study, occurrence of 9 SPAs and their metabolites/degradation products was determined in 339 indoor dust collected from 12 countries. BHT was found in 99.5% of indoor dust samples from homes and microenvironments at concentrations that ranged from < LOQ to 118 μg/g and 0.10 to 3460 μg/g, respectively. This is the first study to measure BHT metabolites in house dust (0.01-35.1 μg/g) and their concentrations accounted for 9.2-58% of the sum concentrations (∑SPAs). 3,5-di-tert-butyl-4-hydroxybenzaldehyde (BHT-CHO), 2,6-di-tert-butyl-4-(hydroxymethyl)phenol (BHT-OH), 2,6-di-tert-butyl-1,4-benzoquinone (BHT-Q) were the major derivatives of BHT found in dust samples. The concentrations of gallic acid esters (gallates) in dust from homes and microenvironments ranged from < LOQ to 18.2 and < LOQ to 684 μg/g, respectively. The concentrations and profiles of SPAs varied among countries and microenvironments. Significantly elevated concentrations of SPAs were found in dust from an e-waste workshop (1530 μg/g). The estimated daily intake (EDI) of BHT via house dust ingestion ranged from 0.40 to 222 ng/kg/d (95th percentile).

Tetrabromobisphenol A (TBBPA) and eight bisphenol analogues (BPs) including bisphenol A (BPA) were determined in 388 indoor (including homes and microenvironments) dust samples collected from 12 countries (China, Colombia, Greece, India, Japan, Kuwait, Pakistan, Romania, Saudi Arabia, South Korea, U.S., and Vietnam). The concentrations of TBBPA and sum of eight bisphenols (ƩBPs) in dust samples ranged from <1 to 3600 and from 13 to 110,000 ng/g, respectively. The highest TBBPA concentrations in house dust were found in samples from Japan (median: 140 ng/g), followed by South Korea (84 ng/g) and China (23 ng/g). The highest ∑BPs concentrations were found in Greece (median: 3900 ng/g), Japan (2600 ng/g) and the U.S. (2200 ng/g). Significant variations in BPA concentrations were found in dust samples collected from various microenvironments in offices and homes. Concentrations of TBBPA in house dust were significantly correlated with BPA and ∑BPs. Among the nine target chemicals analyzed, BPA was the predominant compound in dust from all countries. The proportion of TBBPA in sum concentrations of nine phenolic compounds analyzed in this study was the highest in dust samples from China (27%) and the lowest in Greece (0.41%). The median estimated daily intake (EDI) of ∑BPs through dust ingestion was the highest in Greece (1.6-17 ng/kg bw/day), Japan (1.3-16) and the U.S. (0.89-9.6) for various age groups. Nevertheless, in comparison with the reported BPA exposure doses through diet, dust ingestion accounted for less than 10% of the total exposure doses in China and the U.S. For TBBPA, the EDI for infants and toddlers ranged from 0.01 to 3.4 ng/kg bw/day, and dust ingestion is an important pathway for exposure accounting for 3.8-35% (median) of exposure doses in China., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Siloxanes are used widely in a variety of consumer products, including cosmetics, personal care products, medical and electrical devices, cookware, and building materials. Nevertheless, little is known on the occurrence of siloxanes in indoor dust. In this survey, five cyclic (D3-D7) and 11 linear (L4-L14) siloxanes were determined in 310 indoor dust samples collected from 12 countries. Dust samples collected from Greece contained the highest concentrations of total cyclic siloxanes (TCSi), ranging from 118 to 25,100ng/g (median: 1380), and total linear siloxanes (TLSi), ranging from 129 to 4990ng/g (median: 772). The median total siloxane (TSi) concentrations in dust samples from 12 countries were in the following decreasing order: Greece (2970ng/g), Kuwait (2400), South Korea (1810), Japan (1500), the USA (1220), China (1070), Romania (538), Colombia (230), Vietnam (206), Saudi Arabia (132), India (116), and Pakistan (68.3). TLSi concentrations as high as 42,800ng/g (Kuwait) and TCSi concentrations as high as 25,000ng/g (Greece) were found in indoor dust samples. Among the 16 siloxanes determined, decamethylcyclopentasiloxane (D5) was found at the highest concentration in dust samples from all countries, except for Japan and South Korea, with a predominance of L11; Kuwait, with L10; and Pakistan and Romania, with L12. The composition profiles of 16 siloxanes in dust samples varied by country. TCSi accounted for a major proportion of TSi concentrations in dust collected from Colombia (90%), India (80%) and Saudi Arabia (70%), whereas TLSi predominated in samples collected from Japan (89%), Kuwait (85%), and South Korea (78%). Based on the measured median TSi concentrations in indoor dust, we estimated human exposure doses through indoor dust ingestion for various age groups. The exposure doses ranged from 0.27 to 11.9ng/kg-bw/d for toddlers and 0.06 to 2.48ng/kg-bw/d for adults., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Perchlorate is a widespread environmental contaminant and potent thyroid hormone disrupting compound. Despite this, very little is known with regard to the occurrence of this compound in indoor dust and the exposure of humans to perchlorate through dust ingestion. In this study, 366 indoor dust samples were collected from 12 countries, the USA, Colombia, Greece, Romania, Japan, Korea, Pakistan, Kuwait, Saudi Arabia, India, Vietnam, and China, during 2010-2014. Dust samples were extracted by 1% (v/v) methylamine in water. Analyte separation was achieved by an ion exchange (AS-21) column and analysis was performed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The overall concentrations of perchlorate in dust were in the range of 0.02-104μg/g (geometric mean: 0.41μg/g). The indoor dust samples from China contained the highest concentrations (geometric mean: 5.38μg/g). No remarkable differences in perchlorate concentrations in dust were found among various microenvironments (i.e., car, home, office, and laboratory). The estimated median daily intake (EDI) of perchlorate for toddlers through dust ingestion in the USA, Colombia, Greece, Romania, Japan, Korea, Pakistan, Kuwait, Saudi Arabia, India, Vietnam, and China was 1.89, 0.37, 1.71, 0.74, 4.90, 7.20, 0.60, 0.80, 1.55, 0.70, 2.15, and 21.3ng/kgbodyweight (bw)/day, respectively. Although high concentrations of perchlorate were measured in some dust samples, the contribution of dust to total perchlorate intake was <5% of the total perchlorate intake in humans. This is the first multinational survey on the occurrence of perchlorate in indoor dust., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Surficial sediment samples were obtained from 25 locations within Kuwait Bay and outside the Bay, in the Northwestern Arabian Gulf, to access recent pollution in Kuwait. The historical deposition of PBDEs to this portion of the Arabian Gulf was reconstructed by collecting a sediment core at the entrance of Kuwait Bay. The mean (and range) in concentrations of ∑11PBDEs in surficial sediments was 0.164±0.09 (0.06-0.44) pg/g dw. The concentrations measured in Kuwait Bay were generally higher than those measured in the open Gulf. When the concentrations were normalized to organic carbon, the average ∑11PBDEs concentrations measured in Kuwait Bay were seven times higher than average concentrations outside the Bay. The historical record, reconstructed from a sediment core collected at the entrance of Kuwait Bay, showed that Σ11PBDE concentrations were generally low in deeper sediment sections. The concentrations started to increase above background in the mid-1950s and increased sharply to a maximum Σ11PBDE concentration of ca 1,100 pg/g in the late 1980s. Concentrations decreased thereafter until another pulse in concentrations was observed around the early 2000 followed by a decrease in subsequent years. It is likely that the initial pulse in concentration recorded in sediments is related to inputs from the Gulf war of 1991. The penta congeners were observed throughout the length of the core although the concentrations were low. The congeners present in the Deca-PBDE technical mixture, particularly BDE 209 which is the main congener in the Deca-BDE mixture, occurred in sediment cores around the 1980s, and the concentrations increased rapidly thereafter being the most dominant congener since their first detection in sediments. The presence of nona-BDE congeners in proportions exceeding those in commercial mixtures may be suggestive of debromination of BDE 209 in sediments., (Copyright © 2014 Elsevier B.V. All rights reserved.)

A total of 318 local and imported meat, milk, eggs, fish, and animal feed samples collected in Kuwait were analyzed by cell-based reporter gene assay (Dioxin-Responsive Chemical Activated LUciferase gene eXpression DR-CALUX) for PCDD/Fs and dl-PCBs. The bioanalytical equivalents (BEQs) obtained by DR-CALUX bioassay were compared with the official maximum limits according to the European Commission (EC) regulations. Suspected and randomly chosen negative samples were analyzed by gas chromatography-high resolution mass spectrometry (GC-HRMS). The results showed that among suspected samples, one sample was confirmed to be non-compliant. The positive sample was of imported origin. The correlation coefficient of 0.98 between DR-CALUX and GC-HRMS was found. Moreover, the average daily intakes of PCDD/Fs and dl-PCBs for the Kuwaiti population were estimated. Results obtained in this study were discussed and compared with other published data., (© 2013 Published by Elsevier Inc.)

The study reports fortnightly atmospheric concentrations of PBDEs concomitantly measured at an urban and a remote location over a twelve-month period in Kuwait to examine seasonal variability and urban-rural concentration gradients. The annual mean (and range) of ∑PBDE concentrations was 32 (3-208) pgm(-3) at the remote site and 57 (0.3-445) pgm(-3) at the urban site. Although not statistically significant, the median (29 pg m(-3)) and mean (57 pg m(-3)) concentrations at the urban location were higher than those measured at the remote location (18 and 29 pg m(-3) respectively), consistent with the view that urban centers are an important net source of these compounds to the environment. Although Clausius-Clapeyron plots showed statistically significant correlations (p<0.05) with temperature for low molecular weight congeners (BDEs 28, 47, 100), correlations with the ΣPBDE concentrations were not significant at both urban and remote sites. The seasonal variations in ΣPBDE concentrations were not markedly different at the urban location, but the median summer ΣPBDE concentration at the remote location was significantly higher than winter median ΣPBDE concentrations. The absence in seasonality at the urban location may be due to ongoing primary emissions in urban areas., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Three Legionella pneumophila strains isolated from municipal hot tap water during a multicentric Italian survey and belonging to serogroups 1, 6, 9 and the reference strain Philadelphia-1 were studied to determine the intracellular replication capability and the cytopathogenicity in human monocyte cell line U937 and in an Acanthamoeba polyphaga strain. Our results show that both serogroups 1 and Philadelphia-1 were able to multiply into macrophages inducing cytopathogenicity, while serogroup 6 and ever more serogroup 9 were less efficient in leading to death of the infected macrophages. Both serogroups 1 and 6 displayed a quite good capability of intracellular replication in A. polyphaga, although serogroup 1 was less cytopathogenic than serogroup 6. Serogroup 9, like Philadelphia-1 strain, showed a reduced efficiency of infection and replication and a low cytopathogenicity towards the protozoan. Our study suggests that bacterial pathogenesis is linked to the difference in the virulence expression of L. pneumophila serogroups in both hosts, as demonstrated by the fact that only L. pneumophila serogroup 1 shows the contextual expression of the two virulence traits. Serogroup 6 proves to be a good candidate as pathogen since it shows a good capacity for intracellular replication in protozoan.

The vertical distribution of polychlorinated biphenyls (PCBs) was measured in a dated sediment core from the northwestern Arabian Gulf to reconstruct their depositional history. The downcore profile showed an increase in concentrations from depth to a subsurface maximum of approximately 1,500 pg g(-1) in approximately 1991, followed by an exponential decrease to the sediment-water interface. Current concentrations of ΣPCBs are similar to levels predating the episodic input of PCBs in sediments dated coincident with the 1991 Arabian Gulf war. The spike in ΣPCB concentrations during the war may be related to the destruction of PCB-laden transformers during the conflict. The 15-fold decrease in ΣPCB concentrations from the period of maximum flux to prewar levels suggests that the factors delivering PCBs to sediments at present are similar to those that that existed before the war-related inputs.

This study reports concentrations of PBDEs in surface soil samples collected along a 140 km transect across Kuwait to assess the role of urban centers as sources of persistent organic pollutants to the surrounding environment. The ΣPBDE concentrations varied by a factor of ~250 and ranged from 289 to 80,078 pgg (-1)d.w. The concentrations of PBDEs in Kuwait City were significantly higher (p<0.01) than those collected from sites outside the city supporting the hypothesis that urban centers are sources of PBDEs. The congener profiles were dominated by BDE-209, accounting for 93% of the PBDEs in the soil samples. The concentrations of all congeners (except BDE-209) were highly correlated with percent organic carbon (%OC) (p>0.05) when the data from Kuwait City was omitted from the analysis. These findings suggest that soil concentrations outside the urban centers were close to equilibrium with the atmosphere., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Polybrominated diphenyl ethers (PBDEs) were measured in three species of fish (yellowfin seabream [Acanthopagrus latus, a predatory fish]; Klunzinger's mullet [Liza klunzingeri, a pelagic fish]; and large-scaled tonguesole [Cynoglossus arel, a demersal fish]) collected from two sites in the northwestern part of the Arabian Gulf, a marginal sea of the tropical Indo-Pacific Ocean. Concentrations of ΣPBDEs ranged from 11 to 57 ng g(-1) lipid weight (lw) for mullet, 5.0-38 ng g(-1) lw for tonguesole, and 2.8-48 ng g(-1) lw for seabream in Kuwait Bay, whereas in the open gulf, concentrations ranged from 6.0 to 160 lw for mullet, 8.3-190 lw for tonguesole, and 7.1-62 for lw for seabream. The congener composition in all species from both sites was dominated by BDEs 47, 99, and 100, which together constituted approximately 90% of the congeners detected. Although no statistically significant intersite differences were found, ΣPBDEs concentrations in mullet were significantly higher than those in seabream (p = 0.01). However, no significant differences existed between mullet and tonguesole (p = 0.28) or between tonguesole and seabream (p = 0.06). ΣPBDE concentrations were negatively correlated with fish mass for all species; however, the correlations were statistically insignificant, suggesting a growth dilution effect.

Purpose: The aim of this multicenter prospective study was to provide data from a case series supporting the use of short dental implants with oxidized surfaces to treat partially edentulous patients., Materials and Methods: The implants used had an oxidized surface, a tapered design, and a short length (8.5 mm or shorter). All implants were placed in posterior edentulous areas that were affected by high bone resorption (available bone height < 10 mm). Implant success was established according to predetermined criteria., Results: Records were available for 107 implants used to treat 46 patients (69.2% were 7 mm long, and 30.8% were 8.5 mm long); 80.4% were placed in the posterior mandible, and 19.6% were placed in the posterior maxilla. With regard to restorations, 27.1% of implants were restored with single crowns, 16.8% with a single cantilever, and 56.1% with fixed prostheses. After a 1- to 3- year follow-up, 105 implants are still functioning; only 2 implants have been lost, for a survival rate of 98.1%. In all, 4 of the 107 implants placed failed to meet the success criteria, resulting in a success rate of 96.3%. The mean marginal bone loss was 0.6 ± 0.2 mm., Conclusions: The results of this study suggest that short oxidized implants should be regarded as a possible solution for the restoration of posterior teeth in highly resorbed areas.

Concentrations of polybrominated diphenyl ethers (PBDEs) were quantified in four-hour integrated air samples obtained serially over a five day period in May 2007 in Kuwait City during and after a severe dust storm. The ∑PBDE concentrations ranged from 51 to 1307 pg m(-3) for the first two days of sampling and 20 to 148 pg m(-3) for the rest of the sampling period. The first two days of sampling occurred during a severe dust storm episode when the total suspended particulates (TSP) in air exceeded 1000 μg/m(3) with concentrations peaking during the day and decreasing at night. During this dust episode, the peak nighttime PBDE concentration was 30 times higher than the minimum daytime concentration. Although ∑PBDE concentrations peaked at night during the first two sampling days, the fluctuations in the BDE 47:99 ratio tracked changes in ambient temperature remarkably well, following a clear diurnal pattern. The fraction of congeners in the gas phase varied inversely with solar flux and was lower on days with a high number of hours of sunshine, suggesting that photolytic degradation of gas-phase PBDEs was occurring.

Concentrations of polycyclic aromatic hydrocarbons (PAHs) were determined in 115 samples of olive oil (extra virgin olive oil, virgin olive oil, olive oil, pomace olive oil and blended olive oil), cooking oil (corn oil, sunflower oil, sesame oil, palm olein oil, soya oil, canola oil, mustard oil, peanut oil and mixed vegetable oil) and fat (butter and table margarine) collected from retail stores in Kuwait. Carcinogenic benzo[a]pyrene (BaP) was detected in 43% of the samples analyzed. Benz[a]anthracene and chrysene were detected in 37 and 45% of the samples, respectively, that did not contain BaP. Of the individual non-carcinogenic PAHs, naphthalene showed the highest mean concentration (14 microg kg(-1)), while for the carcinogenic PAHs, BaP (0.92 microg kg(-1)) and chrysene (0.87 microg kg(-1)) showed the highest mean values. Approximately 20% of the samples within the olive oil and cooking oil sub-categories exceeded the EU maximum tolerable limit for BaP, with the highest level of 6.77 and 11.1 microg kg(-1), respectively. For the fat sub-category, 9% of the samples exceeded the tolerance limit, with the highest level of 3.67 microg kg(-1). The Kuwaiti general population's dietary exposure to the genotoxic PAHs (PAH8: benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene, dibenz[a,h]anthracene and benzo[ghi]perylene) was estimated to be 196 ng day(-1) (3.3 ng kg(-1) bw day(-1), assuming an average adult body weight of 60 kg). Results indicated that PAH8 and BaP(eq) (total sum benzo[a]pyrene equivalents) are more reliable measures of the concentrations of other carcinogenic PAHs in oil and fat samples, while BaP and PAHs alone are not good indicators of the occurrence or degree of contamination by carcinogenic PAHs in these food products.

Polybrominated diphenyl ether (PBDE) concentrations were measured in sewage sludge samples collected from three wastewater treatment plants in Kuwait over a six month period. PBDEs were detected in all samples analyzed and there were significant differences between the three wastewater treatment plants. The mean (and range) of summation PBDEs concentrations measured are as follows: Jahra 52.5 ng g(-1) (5.7-169.5 ng g(-1)); Reqqa, 144 ng g(-1) (32-296 ng g(-1)); Umm Haylaman, 377 ng g(-1) (23-1599 ng g(-1)). The differences in concentrations of the sum of penta congeners were consistently different at the three treatment plants with values increasing in the order: Jahra

This study reports concentration of polycyclic aromatic hydrocarbons (PAHs) in indoor air and dust samples collected from 24 homes in Kuwait. Mean SigmaPAHs in indoor air ranged from 1.3 to 16 ng/m(3) with a geometric mean of 5.6 ng/m(3), whereas the dust concentrations varied over three orders of magnitude, from 3 to 2920 ng/g, with a geometric mean of 165 ng/g. The low-molecular-weight tricyclic and tetracyclic PAHs dominated the air profile constituting approximately 70-90 % of the measured compounds, with phenanthrene (51%), fluorene (13 %), fluoranthere (8 %), and pyrene (7 %) being the major contributors. The PAH profile in dust was dominated by the high-molecular-weight PAHs, with three compounds (benzo[a]pyrene, benzo[k]fluoranthene, and benzo[b]fluoranthene) contributing approximately 60% of the average SigmaPAHs measured in the samples. Indoor-to-outdoor (I/O) ratios for individual compounds were <1 for the majority of compounds, suggesting that there were no significant indoor sources for these compounds in these homes. Using the measured concentrations in air and dust, together with estimates of inhalation and inadvertent dust ingestion rates for children and adults, estimated human nondietary exposure on a BaP(equiv) basis were 547 pg/kg body weight/day and 205 pg/kg body weight/day for children and adults, respectively. Exposure from dust ingestion contributes about 42% of nondietary intake of SigmaPAHs in children, but only 11% for adults. The threefold difference in exposure estimates between children and adults in this study supports previous reports that children are at greater risk from pollutants that accumulate indoors.

This study reports concentrations of polybrominated diphenyl ethers (PBDEs) in dust samples collected from 17 homes in Kuwait. PBDEs were measured in all homes investigated with mean summation operatorPBDEs concentration ranging from 1 to 393 ng g(-1), with a geometric mean of 76 ng g(-1). The dominant congener in all samples was BDE 209 constituting ca. 85% of the summationPBDEs followed by BDE 99 (5%), BDE 47 (4.5%), and BDE 183 (2%). The congener mixture in dust is dominated by those in deca and penta formulations. Using the measured concentrations and estimates of dust ingestion rates for children and adults, estimated human non-dietary exposure based on mean PBDE levels were 14.8 and 1.5 ng day(-1) for children and adults, respectively. The 10-fold difference in exposure estimates between children and adults in this study supports previous reports that children are at greater risk from pollutants that accumulate indoors. The ubiquitous distribution of these chemicals as noted in this study highlights the fact that we are continuously exposed to low doses of chemicals in the indoor environment.

The present study presents, to our knowledge, the first ambient air data for a range of polybrominated diphenyl ethers (PBDEs) and polycyclic aromatic hydrocarbons (PAHs) in Kuwait. This was achieved by concurrently deploying polyurethane foam-disk passive samplers at 14 sites over a six-week period. Calculated mean sigma5PBDE concentrations (sum of brominated diphenyl ethers [BDEs] 47, 99, 100, 153, and 154) ranged from 2.5 to 32 pg/m3 of air, with BDE 47 contributing between 39 and 65% of the sigmaPBDEs detected. Differences in relative concentrations were observed between sites, with higher concentrations measured close to suspected sources. Calculated sigmaPAH concentrations ranged from 5 to 13 ng/m3 (mean, 8.3 ng/m3). The compound distribution was dominated by three- and four-ring compounds, which constituted approximately 90% of the sigmaPAHs, with phenanthrene contributing approximately 35%. However, the proportion of five- and six-ring PAHs increased around the "oil lakes," which were formed by the torching of oil wells during the 1991 Gulf War. The oil lakes are a reservoir of PAHs that will continue feeding the atmosphere as long as they remain untreated.

The concentrations of polychlorinated biphenyls (PCBs) were measured in surficial sediments receiving industrial and municipal effluents in Kuwait. The SigmaPCB concentrations varied by two orders of magnitude ranging from 0.4 to 84 microg kg(-1) dw. The homologue distribution in the study favored the more chlorinated congeners and generally followed the order: penta-PCBs > hexa-PCBs > tetra-PCBs approximately hepta-PCBs, with the dominant congeners being 138, 101, 110, 180, 153, 132, 149, and 118. The spatial distribution revealed significant intersite difference in concentration, with high levels encountered close to a harbor and several wastewater outlets suggesting that point source input is the primary delivery mechanism of PCBs to the sediment. This study suggests that atmospheric deposition of PCBs may not be a significant delivery mechanism to sediments in Kuwait possibly due to low annual precipitation and high annual temperatures that are experienced in the Arabian Gulf. The implication of this observation is that PCBs in air are likely to remain in the gas phase long enough to be subject to long-range atmospheric transport to other regions.

Polybrominated diphenyl ether (PBDE) concentrations were measured in surficial sediments from coastal sediments receiving industrial and municipal effluents in Kuwait. The summation PBDE concentrations varied by two orders of magnitude ranging from 80 to 3800 pg g(-1)dw. The congener distribution was dominated by BDE 183, with minor contributions from BDEs 154 and 153. The similarity between the congener profile to that of the technical octa formulation (Bromkal 79-8DE) suggests a source of this product in Kuwait. The observed gradient in concentration distribution, with high summation PBDE concentrations near the shore and an exponential decrease seaward, indicates that wastewater discharge from industrial activities in the study area is the primary source of these compounds in the sediments.

The role of native soil microorganisms in the formation and release of non-extractable (14)C-residues, previously treated with (14)C-Dicamba, was investigated to examine their significance to the longer-term environmental effects on non-extractable pesticide residues. A 90 d study compared the fate of Dicamba under sterile and non-sterile regimes. In addition, soils were aged for 30 d and repeatedly extracted with a 0.01 M CaCl(2) solution, to an extraction end point, to produce non-extractable residues. The extracted soil containing non-extractable residues was mixed with clean soil that had been freshly spiked with non-labeled Dicamba at 0.2 mg kg(-1) to increase the bulk volume of the soil and stimulate microbial activity. Sub-samples were then introduced into microcosms to compare the extent of microbially facilitated release and mineralisation with release rates in sterile microcosms. The results show that microorganisms play a significant role in the formation and release of non-extractable Dicamba residues. The release of (14)C-activity in sterile microcosms was linked to physical mixing of the extracted soil with field soil prior to the beginning of the incubations. The released (14)C-activity may be further mineralized, reincorporated into humus, or taken up by plants or other soil inhabiting biota.

Six major use pesticides (Atrazine, Dicamba, Isoproturon, Lindane, Paraquat and Trifluralin) with differing physico-chemical properties were evaluated for the significance of 'bound' or non extractable residue formation. Investigations were carried out in purpose-built microcosms where mineralization, volatilisation, 'soil water' extractable and organic solvent extractable residues could be quantified. Extractable residues were defined as those accessible by sequential extraction where the solvent used became increasingly non-polar. Dichloromethane was the 'harshest' solvent used at the end of the sequential extraction procedure. (14)C-labelled volatilised and (14)CO(2) fractions were trapped on exit from the microcosm. The pesticides were categorised into 3 classes based on their behaviour. (i) Type A (Atrazine, Lindane and Trifluralin) in which ring degradation was limited as was the formation of non-extractable residues; the remainder of the (14)C-activity was found in the extractable fraction. (ii) Type B (Dicamba and Isoproturon) in which approximately 25% of the (14)C-activity was mineralised and a large portion was found in the non-extractable fraction after 91 days. Finally, Type C (Paraquat) in which almost all of the (14)C-activity was quickly incorporated into the non-extractable fraction. The implications of the data are discussed, with respect to the variability and significance of regulatory aspects of non-extractable residues.