In silico designing of a novel polyvalent multi-subunit peptide vaccine leveraging cross-immunity against human visceral and cutaneous leishmaniasis: an immunoinformatics-based approach.

CONTEXT: Leishmaniasis is a group of vector-borne infectious diseases caused by over 20 pathogenic Leishmania species that are endemic in many tropical and subtropical countries. The emergence of drug-resistant strains, the adverse side effects of anti-Leishmania drugs, and the absence of a preventative vaccination strategy threaten the sensitive population. Recently, many groups of researchers have exploited the field of reverse vaccinology to develop vaccines, focusing chiefly on inducing immunity against either visceral or cutaneous leishmaniasis. METHODS: This present work involves retrieving twelve experimentally validated leishmanial antigenic protein sequences from the UniProt database, followed by their antigenicity profiling employing ANTIGENpro and Vaxijen 2.0 servers. MHC-binding epitopes for the same were predicted using both NetCTL 1.2 and SYFPEITHI servers, while epitopes for B cell were computed using ABCpred and BepiPred 2.0 servers. The screened epitopes with significantly higher scores were utilized for designing the vaccine construct with appropriate linkers and natural adjuvant. The secondary and tertiary structures of the synthetic peptide were determined by conditional random fields, shallow neural networks, and profile-profile threading alignment with iterative structure assembly simulations, respectively. The 3-D vaccine model was validated through CASP10-tested refinement and the MolProbity web server. Molecular docking and multi-scale normal mode analysis simulation were performed to analyze the best vaccine-TLR complex. Finally, computational immune simulation findings revealed promising cellular and humoral immune responses, suggesting that the engineered chimeric peptide is a potential broad-spectrum vaccine against visceral and cutaneous leishmaniasis.

Increasing Number of Therapy Sessions of Repetitive Transcranial Magnetic Stimulation Improves Motor Development by Reducing Muscle Spasticity in Cerebral Palsy Children.

BACKGROUND: Repetitive TMS (rTMS), a non-invasive neuro-stimulation tool based on the principle of electromagnetic induction is recently being employed both for investigational and interventional purposes. The stimulating effect of rTMS on motor cortex areas of the brain leads to increased motor activity and decreased muscle tone in spastic cerebral palsy (CP) patients. OBJECTIVE: This modulatory effect of rTMS is used in this study to evaluate its effect on motor function and spasticity by increasing the number of therapy session and keeping frequency of 10Hz and pulse train of 2500 constant. METHODS: Total thirty spastic CP patients participated in this study after written informed consent from their parents/guardians. The participants were equally divided into three groups, namely, S-20, S-30 and S-40 depending on the number of therapy sessions. The mean age±SD of participants in different groups were 8.9±3.6, 9.5±2.9 and 8.4±3.5 in S-20, S-30 and S-40 respectively. Participants in S-20, S-30 and S-40 were provided 20, 30 and 40 sessions of rTMS therapy respectively followed by physical therapy of 30 minutes daily. Each rTMS session was of 25 minutes duration and was administered once daily for 5 days a week. Prior to start and after completion of the therapy, pre and post assessment of gross motor function measure (GMFM) for motor function and modified Ashworth scale (MAS) for muscle spasticity was performed on all the participants. OUTCOMES: The result of pre-versus-post GMFM score showed that 4.27%, 3.12% and 2.36% motor gain was obtained after 40, 30 and 20 sessions of therapy respectively. In addition, significant reduction in spasticity in both upper and limb muscles was also observed in all the three groups.

Neuromodulatory effect of repetitive transcranial magnetic stimulation pulses on functional motor performances of spastic cerebral palsy children.

BACKGROUND: Neuromodulation is emerging as a new therapeutic field towards treatment of neurological disorders through advances in medical devices. Repetitive Transcranial Magnetic Stimulation (rTMS) is one such neuromodulatory device that has received increasing interest as a tool for modulating cortical excitability that influence motor activity in both normal and diseased population. However, the therapeutic effect of rTMS varies depending on stimulation frequency, intensity, pulse trains, duration, etc. Our previous studies had already demonstrated that higher frequency of 10 Hz was effective in improving the motor activity of spastic CP patients. OBJECTIVE: This study was aimed to evaluate the effect of different rTMS pulses on gross motor performance of spastic CP patients. METHOD: Thirty spastic CP patients were divided equally into three groups P1500, P2000 and P2500 with mean age (in years) 7.7 ± SD4.4, 6.8 ± SD5.3 and 7.2 ± SD5.1 respectively. Gross Motor Function Measure (GMFM) was employed as an outcome measure to assess the motor performance. Constant rTMS frequency of 10 Hz was delivered to each participant but the number of stimulation pulse varied according to the groups; which were 1500, 2000 and 2500 pulses for P1500, P2000 and P2500 group respectively. rTMS therapy of 15 minutes duration was followed by physical therapy of 30 minutes daily for 20 days. RESULT: Statistical analysis of pre versus post GMFM scores of different groups revealed significant result (p < .001) and the improvement in functional motor activity was 2.33% in P1500, 3.58% in P2000 and 5.17% in P2500 group. INTERPRETATION: The result demonstrated modulatory effect of rTMS pulse by improving motor function of spastic CP patients.

Melatonin alleviates hyperthyroidism induced oxidative stress and neuronal cell death in hippocampus of aged female golden hamster, Mesocricetus auratus.

Oxidative stress is a well known phenomenon under hyperthyroid condition that induces various physiological and neural problems with a higher prevalence in females. We, therefore investigated the antioxidant potential of melatonin (Mel) on hyperthyroidism-induced oxidative stress and neuronal cell death in the hippocampus region of brain (cognition and memory centre) of aged female golden hamster, Mesocricetus auratus. Aged female hamsters were randomly divided into four experimental groups (n=7); group-I: control, group-II: Melatonin (5mgkg(-1)day(-1), i.p., for one week), group-III: Hyperthyroid (100µg kg(-1)day(-1), i.p., for two weeks) and group-IV- Hyper+Mel. Hormonal profiles (thyroid and melatonin), activity of antioxidant enzymes (SOD, CAT and GPX), lipid peroxidation level (TBARS) and the specific apoptotic markers (Bax/Bcl-2 ratio and Caspase-3) expression were evaluated. A significant increase in the profile of total thyroid hormone (tT3 and tT4) in hyperthyroidic group as compared to control while tT3 significantly decreased in melatonin treated hyperthyroidic group. However, Mel level significantly decreased in hyperthyroidic group but increased in melatonin treated hyperthyroidic group. Further, the number of immune-positive cells for thyroid hormone receptor-alpha (TR-α) decreased in the hippocampus of hyperthyroidic group and increased in melatonin treated hyperthyroidic group. Profiles of antioxidant enzymes showed a significant decrease in hyperthyroidic group with a simultaneous increase in lipid peroxidation (TBARS). Melatonin treatment to hyperthyroidic group lead to decreased TBARS level with a concomitant increase in antioxidant enzyme activity. Moreover, increased expression of Bax/Bcl-2 ratio and Caspase-3, in hyperthyroidic group had elevated neuronal cell death in hippocampal area and melatonin treatment reduced its expression in hyperthyroidic group. Our findings thus indicate that melatonin reduced the hyperthyroidism-induced oxidative stress and neuronal cell death in the hippocampus region of brain, suggesting a novel therapeutic approach of melatonin for management of cognition and memory function in females under hyperthyroid condition.

Effect of r-TMS over standard therapy in decreasing muscle tone of spastic cerebral palsy patients.

Spastic cerebral palsy (CP) is the one of most common neurological disorders occurring due to damage to the immature brain or any other brain lesion at the time of birth. To aid in making the life of the CP patient meaningful, several interventions such as medical, surgical and rehabilitation have been employed to date. Besides these, recently repetitive Transcranial magnetic stimulation (r-TMS) is a new found approach which is being employed for treating various neurological and psychological conditions. The aim of this study was to observe the effects of r-TMS on muscle spasticity in CP patients by stimulating the motor cortex area of the brain, which is responsible for muscle movements. In this study, 20 subjects diagnosed with CP were recruited and 10 each were placed in two groups, namely the research group (RG) (mean age, height and weight were 7.99 (SD = 4.66) years, 116.7 (SD = 23.57) cm and 21.40 (SD = 10.95) kg, respectively) and the control group (CG) (mean age, height and weight were 8.41 (SD = 4.32) years, 107.9 (SD = 26.33) cm, 21.40 (SD = 12.63) kg, respectively). r-TMS frequencies of 5 Hz and 10 Hz were administered for 15 min daily to patients in RG followed by standard therapy (ST) of 1 h duration daily for 20 days. Moreover, the patients in the control group (CG) were given only standard therapy (ST) of 1 h duration for 20 days. Modified Ashworth Scale (MAS) was used as an outcome measure to determine the level of muscle spasticity. A pre- assessment of MAS score was performed on both RG and CG to determine the level of spasticity prior to starting therapy; and similarly post-assessment after 20 days was done to observe the changes post-therapy. Statistical analysis of pre vs post MAS scores showed that few muscles showed reduction in muscle tightness after administering only ST in the CG. On the contrary, the RG that underwent r-TMS therapy combined with ST showed a significant decrease (p < 0.05) in muscle tightness for all the muscles selected for the therapy.

Effect of Naltrexone on photoperiodic regulation of testicular steroidogenesis in adult golden hamster, Mesocricetus auratus.

Photoperiodic regulation of testicular steroidogenesis through modulation of MT1R expression and local melatonin content is well established. However, additional mediators besides local melatonergic system in photoperiodic control of testicular steroidogenesis in golden hamster have not been studied in detail. Endogenous opioid peptides (EOP) are known to regulate reproduction via acting at multiple levels of the hypothalamus-pituitary-gonadal (HPG) axis. The presence of ß-endorphin, a naturally occurring opioid peptide, and its receptor (µ-opioid receptor, µOR) has been reported in rat testes; however the functional significance of photoperiodic regulation µOR in testicular steroidogenesis is not clear. In the present study, we assessed the effect of Naltrexone (Nal), a µOR antagonist, in photoperiodic regulation of testicular steroidogenesis. Immunohistochemical (IHC) localization and expression of µOR along with the expression of steroidogenic markers in testes was analyzed through western blot analyses. IHC suggest immunoreactivity for µOR in Leydig cells with strong immunoreactivity under SD (short-day) condition, whereas weak immunoreactivity was observed under LD (long-day). The expression of µOR was significantly decreased following Nal administration in both the photoperiodic conditions. The localization and differential photoperiodic regulation of µOR in Leydig cells suggests its involvement in testicular steroidogenesis. Further, Nal administration significantly increased the expression of steroidogenic markers (AR, StAR, P450SCC, LH-R, 3ß-HSD and 17-HSD) and plasma testosterone concentration under SD condition as compared to SD-control. We may therefore suggest that photoperiod differentially regulates the expression of µOR which thereby mediates the inhibitory effect of melatonin on testicular steroidogenesis.

Effect of 2-deoxy-D-glucose induced metabolic stress on testicular steroidogenesis and antioxidant status in golden hamster, Mesocricetus auratus: Role of photoperiod.

The driving force underlying the evolution of reproductive seasonality is the marked seasonal fluctuation in energy availability. It is well established that photoperiod regulates testicular steroidogenesis through modulation of circulatory and local melatonin levels and MT1R expression in golden hamster. However, photoperiodic variation in energy availability and its impact on testicular steroidogenesis and antioxidant status has never been investigated for any seasonal breeder. Therefore, the aim of the present study is to elucidate the role of photoperiod in modulation of metabolic stress induced variation in steroidogenesis and antioxidant status in testes. We experimentally reduced energy availability via administration of 2-deoxy-d-glucose (2-DG), a synthetic glucose analog, in critical- (CP), long- (LD) and short-day (SD) exposed golden hamsters, Mesocricetus auratus and examined testicular steroidogenesis and antioxidant status. Administration of 2-DG decreased testicular steroidogenesis and antioxidant enzyme activity in CP and LD experienced hamsters as compared to CP- and LD-control groups. Moreover, a decrease in the plasma- and local-melatonin level and MT1R expression in testes with a simultaneous increase in plasma corticosterone level was noted following 2-DG administration in CP and LD exposed hamsters. In contrast, no significant effect of 2-DG administration was observed on the parameters investigated under SD condition. Therefore, it can be suggested that the reduction in energy availability under CP and LD condition suppressed testicular steroidogenesis and increased oxidative damage in testis whereas SD induced melatonin might have buffered the 2-DG induced suppression of testicular steroidogenesis and maintained testicular antioxidant status.

Melatonin membrane receptor (MT1R) expression and nitro-oxidative stress in testis of golden hamster, Mesocricetus auratus: An age-dependent study.

Age-dependent decline in melatonin level induces nitro-oxidative stress that compromises physiological homeostasis including reproduction. However, less information exist regarding the age-dependent variation in local melatonin (lMel) concentration and MT1R expression in testis and its interaction with testicular steroidogenesis and nitro-oxidative stress in golden hamster, Mesocricetus auratus. Therefore, we evaluated lMel level along with MT1R expression and its possible interaction with steroidogenesis and nitro-oxidative stress in testes of young (6weeks), adult (15weeks) and old (2years) aged hamsters. Further, we injected the old hamsters with melatonin to address whether age-related decline in lMel and MT1R is responsible for the reduction in testicular steroidogenesis and antioxidant status. Increased expression of steroidogenic markers suggests increased testicular steroidogenesis in adult hamsters that declined in old hamsters. An age-dependent elevation in the level of NOX, TBARS, corticosterone and the expression of iNOS and GR with a concomitant decrease in enzyme activities for SOD, CAT, GSH-PX indicate increased nitro-oxidative stress in testes. Data suggest that reproductive senescence in male hamsters might be a consequence of declined lMel concentration with MT1R expression inducing nitro-oxidative stress resulting in diminished testicular steroidogenesis. However, administration of Mel in old-aged hamsters significantly increased steroidogenesis and antioxidant status without a significant variation in lMel concentration and MT1R expression in testes. Therefore, decreased lMel and MT1R might not be the causative factor underlying the age-associated decrease in antioxidant defence and steroidogenesis in testes. In conclusion, Mel induced amelioration of testicular oxidative insult and elevation of steroidogenic activity suggests a potential role of increased nitro-oxidative stress underlying the age-dependent decrease in steroidogenesis.

Melatonin prevents dexamethasone-induced testicular oxidative stress and germ cell apoptosis in golden hamster, Mesocricetus auratus.

This study investigated the protective effect of melatonin on dexamethasone (Dex), an extensively used anti-inflammatory and immunosuppressive synthetic glucocorticoid, induced testicular oxidative stress and germ cell apoptosis in golden hamster. Hamsters were randomly divided into four groups (n = 7): group I - control; group II - melatonin treated (10 mg kg(-1)  day(-1) ); group III - Dex treated (7 mg kg(-1)  day(-1) ) and group IV - combination of Dex and melatonin. All the injections were administered intraperitoneally for seven consecutive days. The histopathological changes, specific biochemical markers, including antioxidative enzymes, plasma melatonin level and the markers for germ cell apoptosis were evaluated. Dex administration decreased antioxidant enzyme activities (SOD, CAT, GSH-PX ), plasma melatonin level and melatonin receptor (MT1) expression with a concomitant increase in lipid peroxidation (TBARS) and altered testicular histopathology which might culminate into increased germ cell apoptosis as evident from increased Bax/Bcl-2 ratio and caspase-3 expression. However, melatonin pre-treatment enhanced enzyme activities for SOD, CAT, GSH-PX with a simultaneous decrease in Bax/Bcl-2 ratio and caspase-3 expression. Our findings clearly suggest that melatonin improved defence against Dex-induced testicular oxidative stress and prevented germ cell apoptosis, suggesting a novel combination therapeutic approach for management of male reproductive health.

Photoperiodic regulation of melatonin membrane receptor (MT1R) expression and steroidogenesis in testis of adult golden hamster, Mesocricetus auratus.

Photoperiodic modulation of melatonin membrane receptor (MT1R) expression in testis has never been reported for any seasonal breeder. Thus, the aim of the present study was to investigate the expression dynamics of MT1R in testis and its interaction with testicular steroidogenesis in a long-day breeder, Mesocricetus auratus. Hamsters were exposed to different photoperiodic conditions i.e. critical- (CP; 12.5L:11.5D); short-day- (SD; 8L:16D) and long-day- (LD; 16L:8D) for 10 weeks wherein testicular steroidogenesis, local melatonin synthesis and the expression of MT1R were analyzed. SD induced melatonin suppressed testicular steroidogenesis as evident from regressed testicular histoarchitecture, decreased expression of AR, StAR, LH-R, P450SCC and enzyme activities of 3ß- and 17ß-HSD. Differential photoperiodic regulation of MT1R expression in testis suggests its involvement in photoperiodic signal transduction for seasonal adjustment of reproduction. Increased S-NAT (Serotonin N-acetyl transferase) activity and local testicular melatonin under SD condition suggest an inhibitory effect of the local melatonergic system on testicular steroidogenesis. Completely opposite responses were recorded for all the parameters analyzed when hamsters were exposed to CP or LD conditions. In conclusion, we may suggest that photoperiod via regulating circulatory and local melatonin level as well as MT1R expression in testes fine tunes the steroidogenesis and thereby, the reproductive status of male golden hamster.

Intensive rehabilitation combined with HBO2 therapy in children with cerebral palsy: a controlled longitudinal study.

OBJECTIVE: The present study aimed to assess the effect of intensive rehabilitation combined with hyperbaric oxygen (HBO2) therapy on gross motor function in children with cerebral palsy (CP). METHODS: We carried out an open, observational, platform-independent study in 150 children with cerebral palsy with follow-up over eight months to compare the effects of standard intensive rehabilitation only (control group n = 20) to standard intensive rehabilitation combined with one of three different hyperbaric treatments. The three hyperbaric treatments used were: air (FiO2 = 21%) pressurized to 1.3 atmospheres absolute/atm abs (n = 40); 100% oxygen pressurized at 1.5 atm abs (n = 32); and 100% oxygen, pressurized at 1.75 atm abs (n = 58). Each subject assigned to a hyperbaric arm was treated one hour per day, six days per week during seven weeks (40 sessions). Gross motor function measure (GMFM) was evaluated before the treatments and at two, four, six and eight months after beginning the treatments. RESULTS: All four groups showed improvements over the course of the treatments in the follow-up evaluations (p < 0.001). However, GMFM improvement in the three hyperbaric groups was significantly superior to the GMFM improvement in the control group (p < 0.001). There was no significant difference between the three hyperbaric groups. CONCLUSION: The eight-month-long benefits we have observed with combined treatments vs. rehabilitation can only have been due to a beneficial effect of hyperbaric treatment.

Melatonin improves humoral and cell-mediated immune responses of male golden hamster following stress induced by dexamethasone.

Melatonin is known as an antistress and immunostimulator compound while glucocorticoids have immunosuppressive function. The mechanism of action of both the hormones on immune cells is still a question. We found that melatonin improved the effect of dexamethasone (synthetic glucocorticoid) induced immunosuppression of splenocytes and bone marrow GM-CFU along with increased production of serum IL-2, IgG and the receptor expression for melatonin and glucocorticoid in spleen that might be responsible for the proliferation of immune cells. Thus, seasonal variation in peripheral melatonin might be responsible for the improvement of immune status under different stress conditions experienced by the rodents for better survival.

Improvement of oxidative stress and immunity by melatonin: an age dependent study in golden hamster.

Reactive oxygen species (ROS) have been proposed to play an important role in balancing the pro- and antioxidant homeostasis during aging. Melatonin has been suggested as an effective free radical scavenger that might have a role during the process of aging. We observed, that melatonin administration (25 µg/100 g body weight for 30 days) significantly augments the activity of anti-oxidative enzymes like superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) in the plasma, spleen and bone marrow (BM) of young (6 weeks), adult (30 weeks) and old aged (2.5 years) male golden hamster, Mesocricetus auratus. A sharp decline in generation of ROS was observed in peripheral blood mononuclear cells (PBMC) and splenocytes upon melatonin administration in different age group of hamsters. Reduction in the level of thiobarbituric acid-reactive substances (TBARS) and total nitrite and nitrate concentration as metabolites and indicators of nitric oxide (NO) in plasma, spleen and BM were observed along with night time (22:00 h) melatonin concentration in different age group of hamsters after administration of melatonin and compared to the control group (treated with 0.9% saline). General immune parameters like proliferation of splenocytes, PBMC and colony forming ability of GM-CFU were observed following melatonin treatment in different age group, although it was low only in aged hamsters compared to the young and adult. Our data indicates that the age related increase of oxidative load and simultaneously augments the general immunity in aged hamsters.

Arsenic-enriched groundwaters of India, Bangladesh and Taiwan--comparison of hydrochemical characteristics and mobility constraints.

Arsenic (As) enrichment in groundwater has become a major global environmental disaster. Groundwater samples were collected from 64 sites located in the districts of 24-Parganas (S), and Nadia in West Bengal, India (Bhagirathi sub-basin), and 51 sites located in the districts of Comilla, Noakhali, Magura, Brahman baria, Laxmipur, Munshiganj, Faridpur and Jhenaida in Bangladesh (Padma-Meghna sub-basin). Groundwater samples were also collected from two As-affected areas (Chianan and Lanyang plains) of Taiwan (n = 26). The concentrations of major solutes in groundwater of the Padma-Meghna sub-basin are more variable than the Bhagirathi sub-basin, suggesting variations in the depositional and hydrological settings. Arsenic concentrations in groundwaters of the studied areas showed large variations, with mean As concentrations of 125 µg/L (range: 0.20 to 1,301 µg/L) in Bhagirathi sub-basin, 145 µg/L (range: 0.20 to 891 µg/L) in Padma-Meghna sub-basin, 209 µg/L (range: 1.3 to 575 µg/L) in Chianan plain, and 102 µg/L (range: 2.5 to 348 µg/L) in Lanyang plain groundwater. The concentrations of Fe, and Mn are also highly variable, and are mostly above the WHO-recommended guideline values and local (Indian and Bangladeshi) drinking water standard. Piper plot shows that groundwaters of both Bhagirathi and Padma-Meghna sub-basins are of Ca-HCO(3) type. The Chianan plain groundwaters are of Na-Cl type, suggesting seawater intrusion, whereas Lanyang plain groundwaters are mostly of Na-HCO(3) type. The study shows that reductive dissolution of Fe(III)-oxyhydroxides is the dominant geochemical process releasing As from sediment to groundwater in all studied areas.

Trophodynamics of mercury and other trace elements in a pelagic food chain from the Baltic Sea.

Mercury (Hg) and 13 other trace elements (Al, Ti, V, Cr, Fe, Mn, Co, Ni, Cu, Zn, As, Cd, and Pb) were measured in phytoplankton, zooplankton, mysis and herring in order to examine the trophodynamics in a well-studied pelagic food chain in the Baltic Sea. The fractionation of nitrogen isotopes (delta(15)N) was used to evaluate food web structure and to estimate the extent of trophic biomagnification of the various trace elements. Trophic magnification factors (TMFs) for each trace element were determined from the slope of the regression between trace element concentrations and delta(15)N. Calculated TMFs showed fundamental differences in the trophodynamics of the trace elements in the pelagic food chain studied. Concentrations of Al, Fe, Ni, Zn, Pb and Cd showed statistically significant decreases (TMF<1) with increasing trophic levels and thus these trace elements tropically dilute or biodilute in this Baltic food chain. Cu, As, Cr, Mn, V, Ti and Co showed no significant relationships with trophic levels. Hg was unique among the trace elements studied in demonstrating a statistically significant increase (TMF>1) in concentration with trophic level i.e. Hg biomagnifies in this Baltic food chain. The estimated TMF for Hg in this food chain was comparable to TMFs observed elsewhere for diverse food chains and locations.

Mercury in coal ash and its fate in the Indian subcontinent: A synoptic review.

In the Indian subcontinent power generation is mainly dependent upon the thermal power units and coal is burnt as a fuel for the production of heat and electricity. In India, bituminous and sub-bituminous coals are used which contain over 40% of ash. At present, 80-90 million tons of fly ashes are generated from 85 existing coal based thermal power plants. Coal contains trace metals of which mercury is most toxic for humans and aquatic fauna. The problem of mercury in the society is not new, but in recent years the Indian subcontinent has gained the reputation of being "a dumping ground for mercury". This study focuses on mercury in fly ash and its releases to the atmosphere and soils cross the country. The utilisation of coal ash in India is also addressed although it is still in its nascent stage. About 10% of produced fly ashes are used in India whereas in Western countries its use is typically over 70%. Regulations from India's Ministry of Environment and Forestry should increase coal fly ash utilisation, although this would require that cost-effective new technology is put to use. As to the release of Hg from ashes disposed of in the environment, the scarce literature suggests that this is negligible or zero, and less problematic than wet or dry deposition of Hg from flue gases.

Metal contamination at a wood preservation site: characterisation and experimental studies on remediation.

The aim of this investigation was to determine the occurrence of As, Cu, Cr and Zn in the soil at an abandoned wood preservation unit and to examine some possible extractants for the contaminants in the soil. The mean As content of the contaminated surface soils (0-10 cm) was 186 mg kg(-1), where as the mean concentrations of Cu, Cr and Zn in soils from the contaminated area were 26, 29 and 91 mg kg(-1), respectively. The elevated As content in the mineral soils is related to adsorption of inorganic As phases in the fine grained fractions, which are characterised by large surface area and high positive surface charge under the current acidic conditions. Cu and Cr were found to be rather mobile, which is reflected in their lower abundance in soils and significant accumulation in sediments in the drainage leaving the area. The fine fraction of the soil (<0.125 mm) has an average metal content increased by nearly 34% as compared to the <2-mm fraction conventionally used for the analysis and assessment of soil contamination. The <2-mm fraction constitutes approximately 65% of the total weight while the fine fraction (<0.125 mm) constitutes approximately 10%. These facts, taken together, are essential for the choice of remediation measures. Oxalate solutions have been tested as extractants for soil remediation. Dark acid oxalate extraction dissolves the amorphous Al- and Fe-oxides and hydroxides and mobilises the adsorbed inorganic As species. Oxalate also acts as a ligand for the cationic heavy metals, releasing them from exchangeable sites. With a three-step sequential leaching, up to 98-99% of the metals could be removed. At lower concentrations and higher pH, the leaching decreased to approximately 70%.

Atmospheric emissions, depositions, and transformations of arsenic in natural ecosystem in Finland.

For the last 2 decades, special attention has been paid to arsenic due to its high concentration in groundwater in many regions of the globe. There are not very many reports on arsenic concentration in the Finnish ecosystem, although the metal has been known to be highly toxic since ancient times. For the majority of people in Finland, the leading exposure route to arsenic is through food consumption. In this study, it has been observed that atmospheric emissions of arsenic from anthropogenic sources have decreased by 90%, which is due to better control technology and strict regulation. Aquatic discharge also was attenuated from 7.1 metric tons (t) in 1990 to 0.7 t in 1999. The concentration of arsenic aerosols in the atmosphere in Finland varies between 0.46 to 0.75 ng m(-3). Its use in pesticides and insecticides also has been phased out in Finland. There is no information available regarding arsenic species in the Finnish environment. Elevated concentrations of arsenic in groundwater has been reported for many countries. In Finland two hot spots are reported--one in the south of Finland and the second in Lapland. In these areas, arsenic concentration in well water is greater than 10 microg l(-1) (WHO recommended value: <10 microg l(-1)). It is believed that the release of arsenic into the Finnish groundwater is geogenic.