Thin-layer chromatography of 2-methyl-4-chlorophenoxyacetic acid and its soil metabolites

1980

Abstract The thin-layer chromatography of 2-methyl-4-chlorophenoxyacetic acid, 4-chloro- o -cresol and 3-methyl-5-chlorocatechol and their pentafluorobenzyl derivatives has been studied on silica gel as adsorbent with 19 solvent systems. The best separation of the individual components occurred with toluene-benzene-acetic acid (2:2:1). Chloroform-diethyl ether-toluene (1:1:1) was suitable for the group separation of the pentafluorobenzyl derivatives.

Chemical shift reagents in the study of polycyclic alcohols IX—1H NMR spectra of myrtenol and some other primary alcohols

1974

Structure proof of (—)-myrtenol, 3-cyclopentenyl-1-methanol and 5-norbornene-2-endo-methanol has been obtained from their proton magnetic resonance spectra in carbon tetrachloride containing different added amounts of tris(dipivaloylmethanato)europium. For each alcohol, a 1:1 complex structure with Eu(dpm)3 could be computed, in which the calculated pseudocontact shift effects on all skeleton protons of the ring system were consistent with the observed shift effect values. A considerable contact contribution of opposite sign to that of the pseudocontact part of the effect could be estimated for the methylene protons of the CH2OH group.

Screening of halogenated aromatic compounds in some raw material lots for an aluminium recycling plant

2004

Four samples of scrap raw materials for an aluminium recycling plant were screened for the occurrence of persistent halogenated aromatic compounds. The samples contained waste from handling of electric and electronic plastics, filter dust from electronic crusher, cyclone dust from electronic crusher and light fluff from car shredder. In our screening analyses, brominated flame retardants were observed in all samples. Polybrominated diphenyl ethers (PBDE) were identified in all samples in amounts of 245–67450 ng/g. The major PBDE congeners found were decabromo- and pentabromodiphenyl ethers. 1,1-bis(2,4,6-tribromophenoxy)ethane, hexabromobenzene, ethyl-pentabromobenzene, tetrabromobisphenol-…

Polychlorinated organic compounds in the Arctic cod liver: trends and profiles

2000

Polychlorinated organic compounds (POCs) have been measured in Arctic cod liver from Vestertana Fjord for a period of 1987-1998. Significant decrease was observed for DDD (p = 0.043), alpha-HCH (p = 0.001), and gamma-HCH (lindane; p = 0.001). Contents of DDE, 2,3,7,8-tetrachlorodibenzofuran, PCBs, chlordanes, chloronaphthalenes, hexachlorobenzene and polychlorodiphenyl ethers had no significant trend. Contents of three hexa- and two heptachlorodibenzofurans and octachlorodibenzofuran increased slightly from 1987 to 1994, but then at very high rate from 1994 to 1998. Trends of HCHs, profiles of PCBs and levels of chlordanes are in accordance with atmospheric long range transport. The hexa-, …

Organochlorines as Environmental Tainting Substances: Taste Panel Study and Chemical Analyses of Incubated Mussels

1992

Lake mussels (Anodonta piscinalis) incubated in freshwater stations upstream and downstream of a large pulp mill were studied for tainting by a panel of 18 persons. The tasted animal muscle and tissue water samples, and composites of other simultaneously incubated mussels were analyzed for organochlorine compounds. Bad taste scores were obtained for mussels from the nearest station downstream to the pulp mill and were significantly (p < 0.001 **) higher than those from other stations. A similar difference was observed for the measured chlorophenol, chloroanisole and chloroveratrole, chlorocymene and PCB contents. Chloroanisoles and chloroveratroles were indicated to form the main tai…

PCDDs, PCDFs, PCDTs, PCBs and some other organochlorine compounds in pine needles exposed to pulp and paper mill emissions and effects of waste combu…

1997

Concentrations of semivolatile chlorinated organic compounds α-HCH, lindane, HCB, DDT, DDE, DDD, chlordanes and PCBs, and low-volatility compounds PCDDs, PCDFs and PCDTs in pine needles in a recipient area of the emissions from a pulp and paper mill where also waste combustion was done were measured. Mostly, the concentrations were found to be near the background levels. Elevated concentrations of HCB, some PCB congeners and some HxCDF isomers in samples from two sampling points were observed. Some other possible point sources of these compounds are situated in the vicinity of the pulp and paper mill.. Also the community of Pietarsaari is one possible source of the slightly elevated concent…

Long-term Effects of Bioaccumulation in Ecosystems

2005

Extensive damage to organisms and declines in wildlife populations have been observed together with long-term bioaccumulation and biomagnification of persistent xenobiotic chemicals. Heavy metals, especially organic or biomethylated mercury, lead, cadmium and organic tin compounds have caused environmental damage through bioaccumulation on a local scale. Effects on wildife caused by bioaccumulation of persistent organochlorine compounds are more widespread. However, the causal relationship between a biomagnified compound and the long-term effects have been established in only a few cases. Metabolic transformations, and occurrence of several toxic contaminants together in many cases, complic…

Baskets, Ecorisk and Ecotoxa

1988

Abstract BASKETS, ECORISK and ECOTOXA are microcomputerizable systems for preliminary environmental risk evaluation for chemicals. They give numerical values which are useful for further risk assessment. Lists of the BASIC programs are available upon request.

119Sn-NMR Study on Bis(Tri-Butyltin)oxide Derivatives of Phenolic Compounds

1991

Abstract 119Sn-NMR spectroscopy has been utilized in the characterization of various phenolics as their bis(tri-butyltin)oxide, TBTO, derivatives. The present method has been applied both for determination of simple model compounds and for characterization of complex biopolymeric material originating from spent bleach liquor fractionated by an ultrafiltration technique. Based on the large range of 119Sn-NMR chemical shifts of TBTO derivatives of the phenolic compounds and the similar relaxation properties of 119Sn nuclei located in those derivatives, both qualitative and quantitative analytical conclusions can be drawn.

Comparison of extraction methods for polycyclic aromatic hydrocarbon determination in sediments

1990

Different sample preparation methods for the determination of polycyclic aromatic hydrocarbons (PAHs) in lake and river sediments were compared and evaluated. Freeze‐dried sediment materials were e...

Lipid-Filled semipermeable membrane devices and mussels as samplers of organochlorine compounds in lake water.

1995

Semipermeable membrane sampling devices (SPMDs) and caged lake mussels (Anodonta piscinalis) were simultaneously deployed at four lake watercourse sites in Central Finland four weeks in August 1992. This study was part of the regular annual monitoring of the organochlorine compounds (OCC) in pulp-mill recipient watercourses of Finland with bivalves. Chlorohydrocarbons (CHCs), chlorophenol compounds (PCPs), chloroanisoles (PCAs) and chloroveratroles (PCVs) were analyzed from lipid extract of mussels and from the synthetic triolein lipid of the SPMDs. Hexane-diethyl ether (9:1, v/v) dialysis using polyethylene membrane was applied in dean up of the SPMD lipids and, for comparison, to six sets…

Polychlorinated diphenyl ethers, dibenzo-p-dioxins and dibenzofurans in finnish human tissues compared to environmental samples

1995

Finnish human samples from the Helsinki area and Arctic cod samples from Vestertana Fjord (Norway) were analyzed for polychlorinated diphenyl ethers (PCDE) and 2,3,7,8-chloro substituted dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF). The PCDE, PCDD and PCDF contents in human and animal samples from Finland and elsewhere were briefly reviewed. PCDEs were non-detectable in human liver and testis, but some PCDE congeners were identified in human adipose tissue and fat of boiled Arctic cod liver composite. The contents of PCDEs in Finnish human samples were similar to those reported in the literature for human tissues from North America. The estimated concentrations of PCDEs 99, 147 + 153 (…

The M74 syndrome of baltic salmon (Salmo salar) and organochlorine concentrations in the muscle of female salmon

1997

Abstract Organochlorine concentrations in the muscle of female Baltic salmon (Salmo salar), ascending for spawning in the Simojoki River on the north-eastern coast of the Gulf of Bothnia from 1988 to 1992 are given in this paper in relation to reproduction success, monitored as viability of offspring. In spring 1992 and 1993 all the yolk-sac fry of 52 % and 75 % of the females, sampled in autumns 1991 and 1992 respectively, died due to the M74 syndrome, i.e., heavy mortality of yolk-sac fry (YSM). The TEOs of the most frequently detected polychlorinated dibenzofurans (PCDFs: 1,2,3,7,8-PeCDF, 2,3,4,7,8-PeCDF and 2,3,7,8-TeCDF) and those of coplanar PCBs (CB77, CB126 and CB169) were about twi…

Chlorinated phenolic compounds in coniferous needles. Effects of metal and paper industry and incineration

1997

Abstract Pine needles were analyzed for their contents of chlorinated phenolic compounds. Altogether about 30 samples from surroundings of a metal scrap plant, a pulp and paper mill, a hazardous waste incinerator and reference samples outside of the immediate influence of these were analyzed by GC/ECD and GC/MS. Most phenolic compounds in the needles were found to be bound to the plant material and were not extractable as such by organic solvents. The concentrations of some bound chlorinated phenolic compounds were on level of 1–300 ng/g in dried needle. For many compounds the concentrations were remarkably higher in the three years old needles compared to the concentrations in the one and …

13C NMR spectroscopy of four tertiary methyl norbornenols and norbornanols

1975

Carbon chemical shifts and direct 13C1H coupling constants of 2-endo-methyl-5-norbornen-2-exo-ol, 2-exo-methyl-5-norbornen-2-endo-ol, 2-endo-methylnorbornan-2-exo-ol and 2-exo-methylnorbornan-2-endo-ol have been measured from single samples using a dual probe pulse Fourier transform method.

Use of Mussels (Anodonta piscinalis) in the Monitoring of Organic Chlorine Compounds

1988

Chlorophenol Compounds in Snow

1988

Polychlorinated phenols, guaiacols and catechols have been studied in snow from North Pole, North, Central and South Finland. Only Central and South Finland samples contained known compounds above limit of determination 0.5 ng/1. Airborne chlorophenol pollution appeared to be very much higher in South than in Central Finland.

Bioaccumulation of dioxins, coplanar PCBs, PCDEs, HxCNs, R-PCNs, R-PCPHs and R-PCBBs in fish from a pulp-mill recipient watercourse

1993

Abstract Pike, perch and lake bream from the river Kymijoki were analyzed by gas chromatography/mass spectrometry (GC/MS) for toxic polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), hexachlorinated naphthalenes (HxCNs), non-ortho substituted polychlorinated biphenyls (coplanar PCBs) and alkylchloroaromatics of pulp mill origin. In most fish, the only congener of PCDD/PCDFs found was 2,3,7,8-TeCDF (

SIMILARITIES IN BIOACCUMULATION PATTERNS OF POLYCHLORINATED DIBENZO-p-DIOXINS AND FURANS AND POLYCHLORINATED DIPHENYL ETHERS IN LABORATORY-EXPOSED OL…

2003

Sediment and chironomid samples were collected from a river in the vicinity of and downstream from a closed chlorophenol production plant, and they were analyzed for polychlorinated dibenzo-p-dioxins and furans (PCDD/F) and polychlorinated diphenyl ethers (PCDE). Bioaccumulation of these compounds from the sediments by the oligochaeta, Lumbriculus variegatus, and semipermeable membrane devices (SPMDs) was studied in a 28-d bioaccumulation test. The sum concentrations of PCDD/Fs and PCDEs in sediments varied spatially, peaking at the site below the production plant, but the congener composition remained fairly constant throughout the river. The sum concentrations of chironomids, oligochaetes…

Chlorohydrocarbons, PCB congeners, polychlorodioxins, furans and dibenzothiophenes in pine needles in the vicinity of a metal reclamation plant

1995

Abstract Chlorohydrocarbons, PCB congeners, polychlorodioxins, furans and dibenzothiophenes in pine needles in the vicinity of a metal reclamation plant were analyzed by GC/ECD and GC/MS. Wax and the rest of the needles were analyzed separately. As a rule the concentrations of α-HCH (0.5–13.6 ng/g), γ-HCH (0.4–7.3 ng/g), HCB (0.2–3.4 ng/g), PCB congeners (0.2–67 ng/g), PCDDs and PCDFs were higher in the older needles. The ratio of the concentration in the wax to the concentration in the rest of the needles was higher in the younger needles. The concentrations of PCB congeners, TeCDDs and TeCDFs were higher in the needles collected in the area nearest to the plant. The samples, obviously, co…

Organic chlorine compounds in lake sediments. II Organically bound chlorine

1990

Abstract Organically bound chlorine together with inorganic chloride was measured from dated bottom sediment layers of 18 lakes in Central Finland and compared to organic matter contents. Pulp mills were found to be the source of significant increase of the accumulation of all of these materials in the 20th century.

Methods for the Identification of Tainting Terpenoids and other Compounds from Algae

1992

Off-flavour compounds produced by algae in freshwater ecosystems were studied for their structure using integrated sensory and spectroscopic methods: mass spectrometry (MS), nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR). Both solvent extraction and thermal desorption were used to isolate and to introduce the compounds into gas chromatography/mass spectrometry (GC/MS) and gas chromatography/Fourier transform infrared (GC/FTIR) systems. Ten ng of a terpenoid compound gave a readable IR spectrum. For 1H NMR studies the compounds were collected directly into NMR solvent by preparative gas chromatography. About 5 µg of a monoterpenoid compound was needed for a reliable 1…

Estimation of vapor pressures, solubilities and Henry's law constants of selected persistent organic pollutants as functions of temperature

1999

Abstract An internally consistent set of temperature dependent physical-chemical property data was derived for 73 persistent organic pollutants, including polychlorinated biphenyls, diphenylethers, dibenzo-p-dioxins, and dibenzofurans, organochlorinated pesticides and polycyclic aromatic hydrocarbons. Measured data reported in the literature were expanded by different estimation and regression methods. Temperature dependent vapor pressures were estimated from relative gas chromatographic retention times and by a modified Watson equation. Temperature dependent water solubilities were estimated by equations based on mobile order theory modified from Ruelle and Kesselring. The temperature depe…

Survey of organochlorines in Finnish watercourses by caged mussel method

2002

Monitoring organochlorine compounds with caged common lake mussels (Anodonta piscinalis) in the pulp and paper mill recipient watercourses of Finland annually from 1984 produced many statistically significant time trends. A decrease of chlorophenols and chloroguaiacols originating from chlorobleaching were observed in all recipients in parallel with the decreasing discharges from the mills. Metabolites of chlorophenols, chloroanisoles and chloroveratroles were constant. Significantly elevated PCB concentrations were measured in four watercourses. At two of these areas, the PCB concentrations were constant. In contrast, a statistically significant increase of PCB (and DDE) was found at one r…

Analyses of known and new types of polyhalogenated aromatic substances in oven ash from recycled aluminium production

2003

Abstract Persistent aromatic bromine, chlorine and mixed chlorine-bromine compounds were analysed from recycled aluminium smelter (ALS) ashes to explore the impact of brominated flame retardants (BFR) on their formation. Polybrominated diphenyl ethers (PBDE) were the most abundant original BFRs found. Induction furnace ash contained tetra- to octa-BDEs about 2000 ng g −1 in similar congener ratios as the original scrap, but contents of nona- and deca-BDEs were only 25 and 5 ng g −1 indicating their significant degradation in ALS process. In the most non-polar fraction, PCB levels and profiles were similar as earlier ALS ash samples in 1990s. The highest PCB level measured was that of deca-C…

A survey of recent results in passive sampling of water and air by semipermeable membrane devices

1995

Abstract A survey is presented of some recent results for passive sampling of water and air for trace organic contaminants using lipid-filled semipermeable membrane devices (SPMDs). Results of water sampling for trace organochlorine compounds using simultaneously exposed SPMDs and the most universally applied biomonitor (bivalves) are discussed. In general, the total amounts of accumulated analytes available for analysis in bivalves and SPMDs were comparable. However, SPMD controls typically had negligible levels of contamination, which was not always the case for transplanted bivalves, even after prolonged depuration prior to exposure. In surveys of the spatial trends of organochlorines at…

Fate of pulp mill effluent compounds in a finnish watercourse

2013

Chloroorganic chemicals emitted from the pulp and paper mill at nekoski in central Finland were monitored for several years. Concentration time series are used for evaluating the environmental fate and the applicability and validity of an exposure models. Fitted elimination rates of 3,4,5-Tri-, 4,5,6-Tri-, Tetrachloroguaiacol and 2,4,6-Trichlorophenol are approx. 0.22 d(-1), or rather the half-lives are approx. 3 days. The elimination is most likely by biodegradation and transport-controlled. For 2,3,6-trichloro-p-cymene, fate simulations indicate significant volatilization and sedimentation. Good agreement is achieved with a one-dimensional steady-state box model, except for concentrations…

Mercury and chlorinated hydrocarbons in the food chain of Lake Paijanne, Finland

1978

The sediments and various organisms in Lake Paijanne were examined for contaminants. The average mercury content of water plants was 9, of plankton 14, of sediment 114, of zoobenthic predators 83, of fish 332–1510 and of birds 240–13685 μg kg−1 (wet weight). The average PCB content of plants was 3, of plankton 21, of the zoobenthos 44, of fish 36-117 and of birds 219–13490 μg kg−1. The average ΔDDT content of plants was 0.5, of plankton 6, of the zoobenthos 14, of fish 7–42 and of birds 144-8262 μg kg−1. Regional differences in mercury content were most pronounced in sediment and fish. PCB concentration was highest near a town. ΔDDT was quite evenly distributed. Water plant species did not …

Chlorinated and methylated dibenzothiophenes in sediment samples from a river contaminated by organochlorine wastes

2001

Eleven sediment samples from the lower Kymijoki River were analyzed for the occurrence of polychlorinated and polymethylated dibenzothiophenes (PCDT and PMeDTs). The area was heavily polluted by wastes from a pulp chlorobleachery and by leakage from a factory producing wood preservative chlorophenol formulation Ky-5. Levels in the sediments were from <5 to 400, 200 and 50 pg g-1 dw for tetra, penta and hexa-CDT, respectively. The concentrations of mono, di, tri and tetra-MeDTs were in the range of 1–5, 5–85, 5–500 and 15–2300 ng g-1 dw, respectively. PCDT contents in surface sediment (0–3 cm layers) decreased by distance downstream from the bleachery and Ky-5 factory similar to those of the…

Recent Development in Analytical Methods for Identification of Off-Flavour Compounds

1983

The best resolution of individual off-flavour compounds is achieved by glass or quartz capillary gas chromatography. A special two-column system was used by which simultaneous instrumental detection and sniffing (odour desorption) of odorous compounds could be done. The measuring detectors were flame ionization (FID), electron capture (ECD), flame photometric (FPD) and a mass spectrometer (MS). Structural assignments of the odorous substances were done from MS data and verified by model compounds. Before the GC run the sample was collected at the head of the double column using a cold trap device. The sample for analysis was injected in liquid form or, more efficiently, thermally desorbed f…

2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents in extracts of Baltic white-tailed sea eagles

1997

Concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin-(TCDD) equivalents were measured in extracts of Baltic white-tailed sea eagle tissues. Extracts of salmon, ringed seal, and grey seal were analyzed as other predatory species of the same area. Concentrations in eagle and seal tissues were greater than those in salmon. Concentrations of TCDD equivalents (TCDD-EQs) determined by the H4IIE bioassay were compared with toxic equivalents (TEQs) derived from instrumental chemical analyses in fractions containing polychlorinated dibenzo-P-dioxins and polychlorinated dibenzofurans (PCDD/PCDF) or coplanar polychlorinated biphenyls (PCBs). Toxic equivalents were calculated by use of an additive mod…

Simulation of13C NMR chemical shifts for polychlorinated and polybrominated oxybenzenes with two-particle increment scheme

1994

A two-particle system of OY-Cl and OY-Br mixed increments for predicting13C NMR chemical shifts of polyhalogenated polyoxybenzenes has been developed. It has been found that only theortho- and para-interactions of the OY and Hal substituents contribute significantly to the13C chemical shifts and that theortho-effects of the OY located between Ha1 and H and those of the OY located between two Ha1 atoms are different. Additional effects are due to solvating solvents. The increment scheme is predictive over the whole class of compounds under consideration and may be realized on personal computers.

Biological effects of high molecular weight lignin derivatives

2010

Abstract A number of high molecular weight (HMW) lignin derivatives possessing varied chemical properties were screened for their biological effects in order to obtain more information on the possible structural features of HMW lignin-related effects. The studied compounds were both commercial and in-house extracted lignin derivatives. Bioassays used include reverse electron transport (RET), Vibrio fischeri, Daphnia magna , and juvenile rainbow trout ( Oncorhynchus mykiss) hepatocytes. The studied lignin derivatives inhibited the in vitro systems and luminescence of V. fischeri bacteria to some extent–daphnids were not affected. It seems that, at least in the RET assay, certain pH-dependent…

Gas chromatographic-mass spectrometric analysis of chlorinated phenoxyphenols in the technical chlorophenol formulation ky-5′

1984

Abstract The content of polychlorinated phenoxyphenol (PCPP) impurities in the technical chlorophenol formulation Ky-5 (wood preservative) was studied. The phenolic fraction was shown to contain predioxins and isopredioxins, the structures of the components being verified by gas chromatography mass spectrometry of non-derivatized, methylated and acetylated fractions. 2,6-Dichloro-4-(2,4,6-trichlorophenoxy)phenol and 2,6-dichloro-4-(2,3,4,6-tetrachlorophenoxy)phenol were identified by the comparison of their retention times and the mass spectra of their methyl and acetyl derivatives with those of authentic specimens. The amounts of the above components in Ky-5 were ca. 0.8 and 0.2%, respecti…

Chlorinated hydrocarbons and mercury in aquatic vascular plants of lake Päijänne, Finland

1978

Uptake of chlorohydrocarbons from soil by lipid-containing semipermeable membrane devices (SPMDs)

1998

Chlorohydrocarbons (CHCs) were surveyed in contaminated lake shore soil in Central Finland with polyethylene membranes containing synthetic triolein (SPMDs). High levels of hexachlorobenzene (HCBz) and PCBs were found in a significant number of the SPMDs exposed 28 days to 35 soil sampling locations along the 350 meter long shoreline. Distributions of HCBz and PCBs were different as demonstrated by two maximas of HCBz and four maximas of PCBs observed. Soil was also analyzed at selected locations for concentrations of CHCs, organic carbon (OC) and moisture. Steady state environmental fate modeling and simple equilibrium partition estimates based on analytical results both gave the same stea…

Chloroaromatic pollutants in mussels incubated in two finnish watercourses polluted by industry

1997

Abstract Concentrations of different chlorinated compounds were measured in mussels incubated in two polluted watercourses, a river (the River Kymijoki) and a lake (Lake Vanaja) for four weeks in summer 1995. The sum concentrations of polychlorinated phenols (PCP) and biphenyls (PCB) were both about 1 μg/g lipid weight (lw) in Lake Vanaja mussels, while in the River Kymijoki mussels PCPs were non-detectable and PCBs were measured 120 ng/g lIw. The concentrations of toxic polychlorinated dibenzo- p -dioxin (PCDD) and dibenzofuran (PCDF) congeners ranged between

Solvent effects of pyridine on the NMR spectra of carboxylic acids. I—study of the acrylic,trans-crotonic and 3-butenoic acids

1975

Proton magnetic resonance spectral parameters of acrylic, trans-crotonic and 3-butenoic acids, their methyl esters and the corresponding alcohols (COOH substituted by CH2OH) have been measured for 5% (w/v) solutions in carbon tetrachloride and in pyridine-d5 at 33·5 °C. The total solvent effect of pyridine on the shifts of the skeleton protons of the acid was found to consist of three different effects independently measured from the reference samples.

Pairwise effects of chlorine substituents on the13C NMR chemical shifts of dichlorobicyclo[2.2.1]heptanes (norbornanes)

1984

The 13C NMR spectra of nine dichlorinated bicyclo[2.2.1]heptanes (norbornanes) have been measured and assigned. The pairwise effects of chlorine substituents which cause deviations from the additivity of single-substituent effects were investigated and are discussed. The largest effect found is the high-field shift of carbons bearing vicinal cis substituents. In the case of geminal substitution deviations from additivity were found to be to low field and large in the γ, smaller in the β and negligible in the α chemical shifts. The observed deviations for 1,3-disubstituted cases vary from −3.2 to +1.1 ppm at different carbons, allowing no simple explanation. Replacement of α-hydrogen in a di…

Thin-layer chromatography of chlorinated cresols

1977

Abstract The thin-layer chromatography of four chlorinated cresols was studied on five layer materials using eleven solvent systems. Sharp spots were obtained except on Kieselguhr G layers. The best separation of the individual compounds occurred on silica gel-containing layers with dichloromethane as the solvent. Each solvent system was found to cause a different separation on different layers.

Tetra- and pentachlorodibenzothiophenes are formed in waste combustion

1991

Abstract Two different waste combustion samples have been analyzed for tetra- and pentachlorodibenzothiophenes. HRGC/HRMS with a resolution of 20 000 was used for identification. By resolution of 10 000 chlorinated dibenzo-p-dioxins and some unknown compounds gave GC/SIM peaks at the exact masses of the chlorinated dibenzothiophenes. These peaks were no more present by resolution 20 000. Several tetra- and pentachlorodibenzothiophenes were found in both samples. In the other one of the samples the concentrations were seemingly high although exact quantitative determination could not be done.

Environmentally Relevant Properties of All 209 Polychlorinated Biphenyl Congeners for Modeling Their Fate in Different Natural and Climatic Conditions

2009

The temperature dependence of physical properties and degradation lifetimes in the environment of all polychlorinated biphenyl (PCB) congeners (N = 209) were determined. For physical properties, the coefficients A and B in equations log(property) = A(property) − B(property)/T(K) were determined by thermodynamic and QSPR methods and compared with the results of independent methods in the literature. The coefficients Apl and Bpl for liquid state vapor pressure PL, As and Bs for solubility in water SW, Ah and Bh for volatility kH (or kH = PL/SW), and Aow and Bow for lipophilicity (KOW), stored in the database of the fate model program, allowed automatic temperature corrections for realistic fa…

Chlorinated acetic and propionic acids in pine needles from industrial areas

1998

Abstract Concentrations of chlorinated acetic and propionic acids in pine needles from the surroundings of a pulp and paper mill and a metal reclamation plant were measured. Different ways of extraction and chromatographic separation were tried. Ultrasonic extraction with water of the powdered needles was found to be efficient. The acids were analysed as their pentafluorobenzyl esters with GC-ECD. The ECD sensitivity of the pentafluorobenzyl derivatives was good. The detection limit was below 1 ng/g for the chlorinated acetic and propionic acids. The concentrations of dichloroacetic acid and 2,2-dichloropropionic acid in fresh needles were on the 0–4 ng/g level. Monochloroacetic acid, 2-chl…

Mercury in sediments of lake Päijänne, Finland

1978

Measurements of organochloro compounds at a metal reclamation plant

1993

Abstract Kuusakoski Ltd is a metal reclamation company operating world wide. Metals recovered are mainly aluminium, copper and different steels. NaCl and KCl are used in processes. Sampling and emission analysis of PCP's, PCB's, PCDD/PCDF's and PAH's were made from seven processes at plant. Emissions indicate, that large part of chlorinated aromatic compounds are formed due to PVC-plastic in cables and car components. On the basis of this study, we suggest, that chlorinated benzenes, -naphtalens and -diphenyl ethers should also be measured in the emissions.

NMR Study of Kraft Pulp Mill Waste and Natural Humic Substances

1988

High field proton NMR spectroscopy in DMSO-d6 solution is applied for structural analysis of main high molecular fractions of natural humus and waste lignin from kraft pulp mill. The spectra are similar in great part. Main differences appear in p-disubstituted benzene proton and -CH2 -CO-proton signals which are absent in spectrum of waste lignin obviously due to chlorination. A new observation of 51 Hz 1:1:1 triplet in both spectra is discussed.

Analytical Methods of Off-Flavours in the Aquatic Environment

1988

Three nuclei n.m.r. spectroscopy of dimethoate compounds. A large solvent effect on the31PSC1H vicinal coupling

1977

Proton, phosphorus and carbon magnetic resonance spectra of dimethoate, dimethoxon, des-N-methyldimethoate, ω-hydroxydimethoate, trimethyldithiophosphate and O,O-dimethyldithiophosphate in different solvents have been measured. Most of the n.m.r. parameters were characteristic of the structural environment of the corresponding nucleus and solvent-independent. However, in the amide structures dimethoate, dimethoxon, des-N-methyldimethoate and ω-hydroxydimethoate the 31PSC1H vicinal coupling showed an unusually large solvent effect of a 2.3 to 6.5 Hz decrease when CDCI3 was replaced by acetone-d6 or DMSO-d6.

Temperature dependent properties of environmentally important synthetic musks.

2002

Environmental fate determining physical properties including their temperature dependence for five nitro musks and for seven polycyclic musks were estimated. The properties evaluated were vapor pressure in a solid and liquid state (PS and PL), solubility in water (S), Henry's law coefficient (H = PL/S) and log octanol-water partition coefficient (log KOW). Gas chromatography for starting values of vapor pressure estimation and HPLC experiments at 5-20 degrees C for comparison of the theoretical versus experimental solubilities in water were performed. The values of temperature (T) dependence coefficients (Ai and Bi) in equations: log (Property)i = Ai - Bi/T were determined. Values of proper…

Evaluation of entropies of fusion of polychlorinated naphthalenes by model congeners: A DSC study

2006

Abstract Thirteen congeners of polychlorinated naphthalenes (PCN) were synthesized and studied by differential scanning calorimetry (DSC). Melting points (Tm) were obtained for all thirteen, and enthalpies of fusion (ΔHf) were obtained for nine congeners. Melting points of other PCNs, except for five, were found in literature. In addition, experimental ΔHf values determined by DSC were found only for 1- and 2-mono-chloronaphthalenes in the literature. The missing or uncertain values of the eight melting points and 64 enthalpies of fusion were estimated by multiple linear regressions using a set of thirteen molecular descriptors as candidates for independent variables. The stepwise model of …

Alkylated dibenzothiophenes in pine needles from pulp and paper mill environment

1998

Abstract Concentrations of alkylated dibenzothiophenes (C n DBTs) in pine needles in a recipient area of the emissions from a pulp and paper mill where also waste combustion was done were measured. The concentrations (ng/g dry weight) of C 1 DBTs were in the range of 2 DBTs in the range of 3 DBTs in the range of 3 DBTs] > [C 2 DBTs] > [C 1 DBTs]. The pulp mill could not be shown to be the source of C 1 C 3 DBTs in the pine needles. Other possible sources are situated in the vicinity of the pulp and paper mill. Long-range transport, either, cannot be excluded as a possible source.

Organic chlorine compounds in lake sediments. III. Chlorohydrocarbons, free and chemically bound chlorophenols

1990

Abstract Chlorohydrocarbons and free and chemically bound chlorophenols, catechols and guaiacols were measured from lake sediments in Central Finland. Chlorohydrocarbons occurred at low backround levels except chlorocymenes from pulp mills and PCBs near the city of Aanekoski, where a local leakage occurrs. Free chlorophenols (hexane extractables) were found in all 18 areas studied, but the bound ones (extracted with strong alkali) only in the pulp mill reciepient lakes where they dominated. Preliminary analyses of chemically bound chlorophenols in high molecular fractions of spent bleach liquors and pulp mill effluents indicated that majority of chlorocatechols and guaiacols are bound alrea…

NMR spectroscopy in environmental chemistry:1H and13C NMR parameters of tricyclic polychlorinated C10 hydrocarbons and their oxy derivatives based on…

1999

Two-dimensional homo- and heteronuclear NMR chemical shift correlation techniques were applied in the characterization of five tricyclic polychlorinated C10 hydrocarbons, chlordene (1), heptachlor (2), trans-nonachlor (3), α-chlordene (4) and γ-chlordene (5), which are spread globally in the environment owing to their use as insecticides. Approximate and partly contradictory 1H and 13C NMR chemical shifts reported in the literature were corrected in this work. The chemical shift assignments of 1–5 were based on DQF COSY, HMQC and HMBC experiments. In addition, an INADEQUATE experiment was needed to ascertain the 13C chemical shifts assignment of 2. The nJ(H,H)s of 1–5 were solved by compute…

Organochlorine Compounds in the Environment

1988

Recent pollution by organochlorine compounds (OCs) has been found to cause ecological damage, initially by causing declining populations. Poisoning of animals having high OC levels was often found to be similar to poisoning of man and animals in dioxin accidents. Dioxin toxicity has been shown to occur from structural binding of the toxin to a cytosolic receptor, and this action has been extended to many planar and coplanar aromatic OCs which are released into the environment from pesticide uses, dumping of chlorophenol wastes, chlorobleaching of pulp, chlorodisinfection of water, and combustion of OCs or chloride-containing materials. More efficient combustion has been developed to restric…

Isolation and identification of intermediates from biodegradation of low chlorinated biphenyls (Delor-103).

2004

Abstract Microorganism Pseudomonas species P2 metabolizes polychlorinated biphenyls (PCBs) and biphenyl, producing the whole spectrum of intermediates, among them coloured intermediates, which are suitable for the monitoring of PCBs degradation by optical sensors. Knowledge of chemical structures and conditions of development of colour metabolites is necessary for application of optical analytical methods. The main goal of this work was the isolation and identification of intermediates from the biodegradation of the mixture of low chlorinated biphenyls (Delor-103), which is based on the solid phase extraction (SPE) of the whole mixture using LiChrolut EN cartridges, then silylation of the e…

Ecotest device for estimation of environmental fate of chemicals in the laboratory

1995

Abstract A glass vessel device with water volume of 20 L was constructed for fast testing of the fate of a chemical in freshwater watercourse environment. The dynamic system consisted of natural water with throughflow, of 4.5 mL min−1 and bottom sediment from a clean oligohumic lake in Central Finland. Duckweed (Lemna sp.) as plant material, lake mussel (Anodonta piscinalis) and crucian carp (Carassius carassius) as test animals were included in the test device. Tetrachloroguaiacol (TeCG) was dissolved at start to water to make 2 μg L−1 concentration. The same concentration of TeCG was maintained in inflow water. After static and dynamic pre-tests, a dynamic four weeks test at 15°C was run …

Trends of organochlorine compounds in Finnish inland waters

2001

Caged common lake mussels (Anodonta piscinalis) have been used in the monitoring of organochlorine compounds in pulp and paper mill recipient watercourses of Finland annually from 1984 to 1998. Statistically significant decreasing trends of chlorophenols and chloroguaiacols originating from chlorobleaching were observed in all recipients in parallel with the decreasing discharges from the mills. Metabolites of chlorophenols, chloroanisoles and chloroveratroles had no or slightly increasing trends. Elevated PCB concentrations were measured in four watercourses. In two areas, PCBs were found to be significantly increasing, in two other cases they showed no trend. A mill producing recycled pap…

Chlorinated short chain aliphatic hydrocarbons in pine needles by purge and trap gas chromatography/mass spectrometry

1995

The concentrations of volatile chlorinated short chain aliphatic hydrocarbons in pine needles have been measured using purge and trap GC/MS. The concentrations of dichloromethane, chloroform, dichloroethene and tetrachloroethene in the needles were calculated. The concentrations of dichloromethane and tetrachloroethene were highest. As a rule the concentrations were higher in the older needles. The needle samples were collected from five sampling points in an area situated in the Southern Finland in the vicinity of a metal scrab plant. Reference needles were collected in the Central Finland. Needles originated from years 1991, 1992 and 1993.

Polychlorinated diphenyl ethers, dibenzo-p-dioxins, dibenzofurans and biphenyls in seals and sediment from the Gulf of Finland.

1997

Polychlorinated diphenyl ethers (PCDEs), 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) were analyzed in seals from the Gulf of Finland and in sediments from the Gulf of Finland and near Gotland. The sediments included one surface core from both sampling sites. The seal material consisted of 14 ringed seals and 6 grey seals that all were found dead and examined for pathology. The main aims were to scrutinize levels and patterns of PCDEs for the first time in seals from the Baltic Sea and to estimate whether chlorinated compounds mentioned have an influence on an exceptional high mortality that occurred among ring…

Prediction of the carbon-13 NMR chemical shifts of polysubstituted benzenes with homogeneous substituents

1991

A new incremental scheme for the calculation of the 13C NMR chemical shifts in polysubstituted benzenes with homogeneous substituents was derived and applied to spectral prediction for C6XnH6−n where XCH3, C2H5, i-C3H7, CF3, F, Cl, Br, COOH. Owing to the use of only two-particle increments the procedure is simple enough to be carried out on hand calculators, and gives complete agreement with experimental values within a few tenths of a ppm in all cases compared (76 compounds). The 13C NMR chemical shift was predicted for hexaethylbenzene with a good fit to the experiment value, and also for 20 unmeasured compounds. The present scheme can be used as an algorithm in structure-searching progra…

A statistical study of the additivities of substituent effects in the13C NMR chemical shifts of hydroxy- and chloro-substituted benzenes

1980

The 13C NMR spectra of six hydroxybenzenes, all chlorobenzenes, all chlorophenols and eight chlorocatechols are measured and assigned. The additivity of the substituent effects and the usefulness of some corrective parameters are studied with regression analysis. The order of the chemical shifts is most efficiently predicted by the simplest substituent effect model, containing only the direct effects of the substituents, although the 95% confidence limits of the calculated shifts are as high as 5.6 ppm. If the chemical shifts need to be predicted within the measuring errors (approximately 0.05–0.10 ppm, in the present data), the number of necessary corrections is very impractical. The corre…

Structural organic chemistry in ecotoxicology

1993

Abstract Role of the methods of structural chemistry in assessment of the ecotoxic effects of organic compounds is described as examples of fate modeling based on structural properties, screening analyses of the affected population, use of model substances and various structure-specific determination methods. Case examples from literature are given and, in addition, structure screening and verification for a contaminant in herring is described.

Potential Off-Flavour Compounds from Chloro-Bleaching of Pulp and Chlorodisinfection of Water

1983

Chlorobleaching of pulp is the most important source of organochlorine pollutants in the Finnish aquatic ecosystems. Similar types of pollutants are formed during chlorodisinfection of water. The model compound approach employed in our laboratory has revealed the structures and amounts of pollutants formed and has made the interpretation and assay of individual organochlorine compounds in the environment possible. Tainting of fish near chlorination plants is frequently observed. Especially chlorinated phenols and anisoles (microbial metabolites of the former) are chlorination products which are known to have a strong odour and taste at very low concentrations. Other chlorinated products, wh…

Structure and Sensory Analyses of Tainting Substances in Finnish Freshwater Environments

1988

GC/MS/SNIFF/TASTE methods have been used in Finland to identify the causes of three tainting problems in water and one in fish nets. Structure determination was often verified by comparison with authentic compounds. Algal growth was implicated to be the source of geosmin and MIB in river water in Northern Finland and was associated with the appearance of tainting problems in raw water and reservoir water in Åland county. Terpenoids (e.g. camphor), degradation products of natural lipids (e.g. aldehydes, ketones and unsaturated aliphatic compounds) and volatile organohalogen compounds were frequently found in contaminated water but showed minor tainting effects compared to geosmin and MIB. Di…

Organic chlorine compounds in lake sediments. V. Bottom of Baikal near a pulp mill

1990

Abstract Organically bound chlorine (OCl) together with inorganic chloride (Cl − ) was measured from bottom surface samples of the Lake Baikal near a pulp mill and compared to organic matter contents (OM). Although total contents of OCl, Cl − and OM were much lower than, the ratio of OCl to OM was of the same order of magnitude as in pulp mill recipients of Finland.

Polybrominated methoxy diphenyl ethers (MeO-PBDEs) in fish and guillemot of Baltic, Atlantic and Arctic environments

2003

Arctic cod liver samples from Vestertana Fjord at the Arctic coast of Norway, salmon and guillemot samples from the Baltic Sea and the Atlantic Ocean, and salmon and lamprey larva samples from Kymijoki River in southern Finland were analysed for the occurrence of tri-, tetra- and pentabromomethoxy diphenyl ethers and their concentration levels were estimated. These compounds have previously been identified by other research groups in salmon, seal and dolphin samples. The aim of this study was to find out a possible temporal trend in the concentrations of these compounds in the cod liver samples from years 1987-1998 and to investigate the possible spatial differences in the concentrations in…

Evaluation of biodegradation of nonylphenol ethoxylate and lignin by combining toxicity assessment and chemical characterization.

2009

Abstract The aerobic biodegradation of commercial nonylphenol ethoxylate (NPE) mixture and alkali lignin was studied using the OECD headspace test accompanied by the simultaneous measurement of ecotoxicity directly from the biodegradation liquors and by the follow-up of the chemical composition of the studied chemicals. NPE degradation was dependent on the inoculum source: approximately 40% of NPE was mineralized into CO2 during the 4-week experiment when inoculum from Helsinki City wastewater treatment plant (WWTP) was used, and only 12% was mineralized when inoculum from Jyvaskyla City WWTP was used. Chemical analyses revealed a shift in the ethoxylate chain length from longer to shorter …

Organic chlorine compounds in lake sediments. IV. Dioxins, furans and related chloroaromatic compounds

1990

Abstract Polychlorodibenzo-p-dioxins (PCDDs), polychlorodibenzofurans (PCDFs), polychloronaphthalenes (PCNs) and coplanar PCBs were measured in surface sediments from 18 lake areas in Central Finland. Toxic 2, 3, 7, 8-substituted PCDD and PCDF congeners occurred at low levels (

Estimation of the environmental hazard of organochlorines in pulp mill biosludge used as soil fertilizer

1993

Abstract Contents of total organic chlorine and polychlorinated phenols, guaiacols, catechols, benzenes, cymenes, cymenenes, naphthalenes, toxic dibenzodioxins, toxic dibenzofurans, toxic PCB congener 77, alkylated dibenzofurans, alkylated bibenzyls and alkylated phenanthrenes in spent biosludges from activated sludge treatment plants of chlorobleaching kraft pulp mills are reported. Some estimations of hazard caused by these organochlorines to humans and wildlife from the use of biosludge as soil fertilizer are constructed and discussed.

Characterization of high molecular mass material in ECF and TCF bleaching liquors by Py-GC/MS with and without TMAH methylation

2006

Abstract High molecular weight (HMW) fractions (MW > 1000) of effluents were obtained by ultrafiltration of elemental chlorine-free (ECF) bleaching (O-D-EOP-D-ED) and totally chlorine-free (TCF) bleaching (O-Z-Q-P-Z-Q-P-P) liquors of softwood (Pinus sylvestris) pulp. The fractions were studied by analytical pyrolysis coupled to gas chromatography/mass spectrometry (Py-GC/MS) with and without TMAH (tetramethyl ammonium hydroxide) derivatization. The pyrograms showed a number of pyrolysis products mainly derived from lignin and carbohydrates. The comparison of 4-hydroxyphenyl (H), guaiacyl (G) and syringyl (S) lignin units in both bleaching effluents showed that the G unit content was clearly…

Ethoxyresorufin-O-deethylase induction potency of polychlorinated diphenyl ethers in H4IIE rat hepatoma cells

1996

Polychlorinated diphenyl ethers (PCDEs) are structurally similar to polychlorinated biphenyls (PCBs), and some PCDE congeners have been reported to cause toxic responses similar to those caused by some of the non-ortho-substituted PCBs, which are mediated by the aryl hydrocarbon receptor (AhR). Twenty-nine PCDEs were tested for their potency as AhR agonists relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) by measuring their ability to induce the cytochrome P-450 1A1-associated enzyme activity, ethoxyresorufin-O-deethylase (EROD), in the H4IIE rat hepatoma cell bioassay. All PCDE congeners tested were found to be inactive as EROD inducers except for PCDE 156, which was a weak E…

New types of environmental POPs

1998

Recent knowledge on sources, biomagnification and ecotoxic potential of earlier less studied persistent organic pollutants (POP) is briefly reviewed. Chlorohydrocarbons discussed are techno‐chemicals polychloronaphthalenes (PCN), polychloroterphenyls (PCT), octachlorostyrene (OCS) and hexachlorobutadiene, pulp bleachery wastes chlorocymenes (CYMS), chlorocymenenes (CYMD), alkylpolychlorophenanthrenes (RPCPH), alkylprolychlorobibenzyls (RPCBB) and alkylpolychloronaphthalenes (RPCN), and fish contaminants polychlorofluorenes (PCFL) and fluorenones (PCFLO), alkyl polychlorofluorenes (RPCFL), polychlorodihydroanthracenes (PCDHA) and polychloroanthracenes (PCAN). Aromatic chloroethers discussed …

1H and13C n.m.r. spectra of dichloro(trans-2-chlorovinyl)arsine

1977

Proton and carbon magnetic resonance spectra of Lewisite or dichloro(trans-2-chlorovinyl)arsine have been measured and the results are compared with the n.m.r. spectral parameters of other trans-1,2-substituted ethylenes. The coupling constants can be rationalized by substituent electronegativity. The chemical shifts show an unusually large paramagnetic effect from the AsCl2 group.

The decomposition of 1-phenyl-3-chloro-nortricyclene and 1-phenylnortricyclene on reduction in 1,2-dimethoxyethane. The EPR spectra of the radical io…

1972

Radical anions of 1-phenyl-3-chloronortricyclene and 1-phenylnortricyclene were produced by reduction with potassium in 1,2-dimethoxyethane under a high vacuum. The initially formed radical anion of 1-phenyl-3-chloronortricyclene was very unstable, and decomposed finally to the anions of naphthalene and biphenyl. The only product of the reduction of 1-phenylnortricyclene was the biphenyl anion. The EPR spectra of the reaction mixtures were measured at temperatures from —80°C to room temperature.

Chlorophenanthrenes, alkylchlorophenanthrenes and alkylchloronaphthalenes in kraft pulp mill products and discharges

1994

Abstract Chlorinated phenanthrenes (PCPHs; P=1–5), alkylphenanthrenes (C4-PCPHs; P=1–3), dimethylnaphthalenes (C2-PCNs; P=1–4) and trimethylnaphthalenes (C3-PCNs; P=1–2) were analyzed by high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS) in pulp, effluent and biosludge of two kraft pulp mills (mills 1 and 2). These compounds were indicated to be formed in the manufacture of both bleached hardwood and softwood kraft pulp. Different compound groups dominated in mill 1 samples compared to mill 2 samples. Differences between birch and pine pulp from mill 1 were observed for all substance groups but in mill 2 pulp only for PCPHs. The highest concentrations of PCPHs …

PCDEs, PCBs, PCDDs AND PCDFs in black guillemots and white-tailed sea eagles from the Baltic Sea

1995

Abstract Concentrations and patterns of several chloro compounds including polychlorinated dibenzo p-dioxins (PCDD), dibenzofurans (PCDF), biphenyls (PCB) and diphenyl ethers (PCDE) were determined in black guillemots ( Cepphus grylle L.) and white-tailed sea-eagles ( Hallaeetus albicilla L.) from the Baltic Sea environment. Three breast muscles of eagles were analyzed and had different concentrations and patterns of the studied compounds, whereas the three guillemot eggs were found to have more similar levels and patterns. The concentrations of individual PCDE congeners varied from

Chloroterpenes and other organochlorines in Baltic, Finnish and Arctic wildlife

1991

Abstract Chloroterpene mixtures were analyzed as toxaphene (TOX) in Baltic, Finnish and Arctic fish, seal and bird samples together with DDT residues, hexachlorocyclohexanes (HCH), hexachlorobenzene (HCBz), chlordanes, hexachloronaphthalenes (HxCN), PCBs, PCDDs and PCDFs. TOX was found to be the most globally (evenly) distributed organochlorine compound in Scandinavia, thus far. TOX seemed to bioaccumulate significantly in fish but not in predatory birds in Finland.

Free and bound chlorophenols in kraft pulp bleaching effluents

1992

Abstract Free (F; hexane extractable) and chemically bound (B; alkali extractable) chlorophenols, catechols and guaiacols were measured from effluents of the C and E stages of chlorobleaching of kraft softwood pulp. Ratio B/F was in moste cases nearly one, but for tetrachloroguaiacol B/F was 20 in C and 2.70 in E stage. Organically bound chlorine (OCl) in chlorophenols was less than one percent of the total AOX (Adsorbable Organic Halogen) emitted.

POPs and organic polysufides in sediments of Lake Ladoga

2007

Abstract The study included one station close to a pollution source (depth 59 m) and another far from polluted areas (depth 40 m). Samples were analysed for organic chlorine, bromine and sulfur compounds. Samples taken with a corer were sliced to the layers of 0–1, 1–4, 4–7 cm etc. down to the depth of 34 cm. The dating was made with two independent methods, the 210Po method and with the soot particle counting method. The analyses were made with a multiresidue method. Gas chromatography was connected to low resolution mass spectrometry (LRMS) or to high resolution mass spectrometry (HRMS). A different extraction was applied to screen the possible occurrence of polysulfides. Typical chloroph…

Degradation half-life times of PCDDs, PCDFs and PCBs for environmental fate modeling.

2000

Literature search of the knowledge on the degradation of persistent organic pollutants (POPs) in environmental compartments air, water, soil and sediment was done in purpose to find properties of POPs of interest for modeling. One degradation process, hydrolysis (chemical degradation), was omitted as negligibly slow for POPs studied. The other two, photolysis and biodegradation processes, were considered separately in purpose to develop estimation procedures. The estimates can be given as pseudo first-order rate constants kP for photolysis and kB for biodegradation. For each compartment, an overall degradation rate is k(tot) = kP + kB and lifetime t(1/2) = ln 2/k(tot). The latter values, li…

Carbon-13 chemical shifts of bicyclic compounds

1970

13C NMR absorption spectra of 50 bicyclic hydrocarbons, alcohols and ketones have been measured, in addition to some terpenes. The 13C chemical shifts are approximately additive for similar compounds and can be used for the determination of molecular structure; they differ for endo- and exo-isomers, just as in proton spectra. These quite regular and predictable 13C shift differences are much larger and are caused by the 1,4-nonbonded interaction between atoms heavier than hydrogen, not by magnetic anisotropy effects.