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

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 Äänekoski, 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 already in the factory.     

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

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.     

Dioxins and furans formation in pilot incineration tests of sewage sludge spiked with organic chlorine

The factors affecting polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) formation were studied in sewage sludge incineration tests carried out on a demonstrative plant. The plant includes a circulating fluidised bed furnace (FBF) and a rotary kiln furnace (RKF), operating alternatively. During the tests sewage sludge was spiked with chlorinated hydrocarbons and the operating parameters of the afterburning chamber were varied. PCDD/F were sampled in each test before the bag filter, thus collecting the above contaminants before abatement systems. From the tests it appeared that PCDD/F were always produced in more abundance in the tests carried out by FBF than by RKF. The higher PCDD/F concentrations in the tests by FBF were reached when sewage sludge was spiked with a high dosage of a surrogate organic mixture of chlorinated hydrocarbons and when the afterburning chamber was used only as transit equipment with the burner off. The distribution of the different PCDD/F homologues was compared. P5CDFs were generally the prevalent fraction, with very few exceptions for the tests by RKF at high temperature of the afterburning chamber. As for FBF tests, it was found that the PCDD/F homologue profile depends on the afterburning chamber temperature.     

Thermal properties of dioxins, furans and related compounds

Vapor pressures are important parameters for modeling of environmental fate and incineration behaviour of chloro-dibenzodioxins and -dibenzofurans. Vapor pressures, enthalpies and entropies of sublimation were measured for four dibenzofurans and were compared to corresponding data on chlorodioxins. A vapor pressure correlation method, which uses the liquid phases as reference states was introduced. Boiling points, enthalpies and entropies of fusion could be calculated from the vapor pressure data by this method. The determined parameters were correlated with the degree of chlorine substitution and the correlations permit the estimation of boiling points, enthalpies of fusion and of sublimation pressures of n-chlorodioxins and -furans of known melting points. The predicted vapor pressures of 2,3,7,8-TCDD were found to be in good agreement with literature reportings.     

Dioxins and related compounds: Status and regulatory aspects

Several countries have put much effort in dioxin research programmes with the aim to assess the risks of dioxin exposure, to identify dioxin sources and to quantify their contribution to environmental emissions and human exposure. In this review, the accent has been put on: sources of dioxins and their contribution to the total dioxin emissions, sources of human exposure and their contribution to exposure and measures to reduce emission and exposure. The information from countries with existing dioxin regulations is reviewed and compared. Uncertainties which hamper comparability of data are indicated. Results of measures and expectations for the near future are presented.     

Dioxins and furans in emissions from medical waste incinerators

Dioxins and furans were detected in emissions from eight medical waste incinerators tested in California. Total uncontrolled emissions ranged from 363 to 11, 811 nanograms per dry standard cubic meter. The most effective of three wet scrubbers achieved an emissions control efficiency of 95 percent for total PCDD and PCDF. A baghouse was less than 30 percent efficient in removing PCDD and PCDF from the incinerator emissions.     

Preliminary report: Dioxins and furans in prescribed burns

The Ontario Ministry of Environment (MOE) recently participated in a joint Canadian/U.S. program to monitor the behavior and environmental impact of prescribed fires. Air, soil and ash samples were collected at the burn sites and analyzed for chlorinated dibenzo-p-dioxins (CDD) and dibenzofurans (CDF). Preliminary results indicated that larger air sample volumes were required.     

Dioxins,furans and polycyclic aromatic hydrocarbons emissions from a hospital and cemetery waste incinerator

An experimental campaign was carried out on a hospital and cemetery waste incineration plant in order to assess the emissions of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polycyclic aromatic hydrocarbons (PAHs). Raw gases were sampled in the afterburning chamber, using a specifically designed device, after the heat recovery section and at the stack. Samples of slags from the combustion chamber and fly ashes from the bag filter were also collected and analyzed. PCDD/Fs and PAHs concentrations in exhaust gas after the heat exchanger (200–350 °C) decreased in comparison with the values detected in the afterburning chamber. Pollutant mass balance regarding the heat exchanger did not confirm literature findings about the de novo synthesis of PCDD/Fs in the heat exchange process. In spite of a consistent reduction of PCDD/Fs in the flue gas treatment system (from 77% up to 98%), the limit of 0.1 ng ITEQ Nm⁻³ at the stack was not accomplished. PCDD/Fs emission factors for air spanned from 2.3 up to 44 μg ITEQ t⁻¹ of burned waste, whereas those through solid residues (mainly fly ashes) were in the range 41–3700 μg ITEQ t⁻¹. Tests run with cemetery wastes generally showed lower PCDD/F emission factors than those with hospital wastes. PAH total emission factors (91–414 μg kg⁻¹ of burned waste) were in the range of values reported for incineration of municipal and industrial wastes. In spite of the observed release from the scrubber, carcinogenic PAHs concentrations at the stack (0.018–0.5 μg Nm⁻³) were below the Italian limit of 10 μg Nm⁻³.     

Organic phosphorus species in surface sediments of a large,shallow, eutrophic lake,Lake Taihu,China

Organic phosphorus (P) fractions in surface sediments from a large shallow, eutrophic Lake Taihu, China, were extracted with 0.1 M NaOH after pre-treatment of the sediments with a solution composed of 0.1 M EDTA and 2% (w/v) Na₂S₂O₄. Composition of organic P in the extracts was then characterized by ³¹P nuclear magnetic resonance spectroscopy (³¹P NMR). Several P species, including phosphonates, orthophosphate, orthophosphate monoesters, phospholipids, DNA, pyrophosphate and polyphosphate, were detected in the NaOH extracts. The proportion of extracted organic P to total P in sediments was negatively correlated with total P in the water column, as were the proportions for orthophosphate monoesters and DNA. This implies that the majority of organic P in surface sediments is likely stabilized in some way, and does not directly contribute to the internal loading of P from sediments.     

Cesium-137 and mercury contamination in lake sediments.

The contribution of fluvial discharge and global fallout of 137Cs and mercury to sedimentation fluxes in Lake Shinji and Lake Nakaumi, Japan, was studied. The fluvial flux through soil erosion accounted for 11 to 27% of accumulated 137Cs in the sediments in the 1950's and 1960's, which were the periods of the most extensive atmospheric input, and for 90 to 100% in the 1990's. The vertical profiles of mercury concentrations in the lake sediments studied showed a maximum between 1959 and 1963, which was originated mostly from the extensive use of mercury-agrochemicals in paddyfields of the watershed in the past. These findings are representative examples of long-term contamination of lake sediments caused by the contaminated ground soil erosion.     

Formation and decomposition of chloroaromatic compounds in chlorine-containing benzene/oxygen flames

Premixed chlorine-containing, fuel-rich, low-pressure benzene/oxygen flames were analysed for the formation of (oxygenated) chloroaromatic compounds and their radicals by means of the condensation/radical-scavenging method (Hausmann, M., Homann, K.-H., 1995. Ber. Busenges. Phys. Chem. 99, 853-862). Several chlorinated organic compounds (methyl chloride, t-butyl chloride, chlorobenzene, chloroform) were used as additives within a maximum concentration of 10% of total fuel. Product identification and quantification were performed by GC/MS. The extent of formation of chloroaromatic compounds in these flames was largest in the cases of chlorobenzene and chloroform as additives. For chlorobenzene, 12 different chloroaromatics could be analysed in between C7H7Cl and C12H9Cl. Their formation is mainly due to conversion of initial chlorobenzene into substituted or oxidised derivatives, or growth products. Additional chlorination of aromatics is shown to be of minor importance in chlorobenzene-containing flames. Three isomeric (o/m/p) scavenging products could be identified for the chlorophenyl radical. In the chloroform case, 15 chloroaromatics could be analysed in between C6H5Cl and C14H9Cl. The weak C-Cl bond in chloroform is responsible for the high extent of chloroaromatics formation, either by Cl abstraction from the additive or by chlorination reactions via Cl radicals. Additionally, specific pathways to (di)chloroaromatics and chlorinated fulvene-type structures are outlined via CHCl2 and CCl2 radicals.     

Dioxins and furans in the Jordanian environment part 2: Levels of PCDD and PCDF in human milk samples from Jordan

Thirty individual human milk samples were gathered from five main towns in Jordan. They were mixed to six pooled samples and analyzed for PCDD and PCDF. All examined samples were contaminated with 1,2,3,4,6,7,8-HeptaCDD (3.2 – 96.0 n&/kg fat) and OctaCDD (29.0 – 147 ng/kg fat). The calculated TEQ (BGA)-values range between 026 and 60.32 ng TEQ/kg fat, which are all above the calculated tolerable concentration of 019 ng TEQ/kg milk fat.     

Polychlorinated dibenzo-p-dioxins/furans and polychlorinated biphenyls in sediments and aquatic organisms from the Taihu Lake, China

Sediments at 16 sites and muscles of four aquatic species collected in Taihu Lake were analyzed for polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) by HRGC/HRMS. The concentrations of total PCDD/Fs, PCBs and WHO-TEQ were 120.1-1315.1pg/gdw, 889.7-29747.8pg/gdw, and 0.83-17.72pgTEQ/gdw, respectively in sediments; and those in muscles were 5.49-35.84pg/gww, 1517.10-27647.98pg/gww, and 0.52-3.83pgTEQ/gww respectively. The concentrations of PCDD/Fs and PCBs in the sediments were decreasing gradually along the water flow. The pollution levels were compared with other studies and the possible sources were discussed.     

湖泊底泥磷释放及磷形态变化

为研究底泥中内源性磷释放对城市景观水体富营养化的影响,以西安市曲江南湖为对象,采用底泥磷形态标准测试方法(SMT)分析了磷的赋存形态,通过模拟实验探究了在不同环境条件(温度、pH和溶解氧)下磷形态变化的特征。结果表明:温度升高促进内源磷的释放,在夏季加剧水体富营养化程度;碱性条件有利于磷的释放,增大补给水源可减少底泥释磷量;厌氧环境下底泥释磷量是好氧时的3.96倍;Al-P 和Ca-P较稳定,在酸性条件下会加速其溶解;NH4+-P、 Fe-P 和OrgP受溶解氧、pH和温度影响较大,其吸附与释放能力有明显的差异。     

Tin compounds in sediments of Lake Maryut, Egypt

Concentrations of inorganic, methyl- and butyltin compounds were quantified by a hydride derivatization/atomic absorption technique for eleven short sediment cores sampled from Lake Maryut, Alexandria, Egypt. All samples contained inorganic Sn concentrations ranging from 1875 to 8190 ng g(-1) dw, the highest levels occurring in the eastern portion of the lake. Methyltin concentrations were also highest in the eastern lake, decreasing considerably in the western lake. Mono- and dimethyltins were found at all sites, the former species being the highest in concentration. Trimethyltin was much lower than either, and was absent from four out of 11 sites. An opposite trend was observed for the butyltin species, their concentration being highest in the west lake, decreasing eastward. Mono- and dibutyltin were almost equal in concentration. Although tributyltin was absent from one site in the lake, it was much higher in concentration than the two other species, particularly in the western lake. In general, methyl- and butyltin concentrations decreased with depth in the cores. Methyltin compounds appear to form within the lake mainly by methylation of inorganic Sn, and butyltin compounds are derived from anthropogenic sources. No significant correlations were found between organic C and concentrations of methyltin species. A significant negative correlation was found between total butyltin concentrations and organic C in surficial sediments.     

Sedimentation and seasonal variation of hexachlorocyclohexanes in sediments in a eutrophic lake,China

Hexachlorocyclohexane (HCH) concentrations in sediments and sediment trap fluxes of particulate organic carbon and HCHs were measured bi-weekly from March 31 to October 18, 2006 in an urban eutrophic lake in Tianjin, China, in order to investigate sedimentation and seasonal variation of HCHs in sediments. HCH concentrations (dry weight basis) ranged from 2.2 to 20.2 ng/g (mean 7.7 ng/g) in surface sediments and from 26.6 to 972.7 ng/g (mean 187.0 ng/g) in settling particles, respectively. A clear seasonal variation in HCH sedimentation and HCH concentrations in sediments was observed. The maximal HCH deposition occurred following a spring phytoplankton bloom. The average flux of HCHs to sediment was approximately 21-fold higher in April to mid-June as compared to late June to October. This was attributed to the high vertical fluxes at the end of the spring phytoplankton bloom. The maximum values of HCH concentrations in sediments were observed in mid-June to late July. Concentrations of HCHs in sediments from the eutrophic lake were well-correlated with organic carbon contents in sediments. The annual sediment trap flux of HCHs in the eutrophic lake, which was estimated using data obtained in the eutrophic lake, was 117 μ g/m² yr, about 72% of which was attributed to the sedimentation corresponding to spring bloom phytoplankton deposition in late May to mid-June. The high sediment trap flux of HCHs in the eutrophic lake was related to serious local contamination.     

Sedimentation and seasonal variation of hexachlorocyclohexanes in sediments in a eutrophic lake, China

Hexachlorocyclohexane (HCH) concentrations in sediments and sediment trap fluxes of particulate organic carbon and HCHs were measured bi-weekly from March 31 to October 18, 2006 in an urban eutrophic lake in Tianjin, China, in order to investigate sedimentation and seasonal variation of HCHs in sediments. HCH concentrations (dry weight basis) ranged from 2.2 to 20.2 ng/g (mean 7.7 ng/g) in surface sediments and from 26.6 to 972.7 ng/g (mean 187.0 ng/g) in settling particles, respectively. A clear seasonal variation in HCH sedimentation and HCH concentrations in sediments was observed. The maximal HCH deposition occurred following a spring phytoplankton bloom. The average flux of HCHs to sediment was approximately 21-fold higher in April to mid-June as compared to late June to October. This was attributed to the high vertical fluxes at the end of the spring phytoplankton bloom. The maximum values of HCH concentrations in sediments were observed in mid-June to late July. Concentrations of HCHs in sediments from the eutrophic lake were well-correlated with organic carbon contents in sediments. The annual sediment trap flux of HCHs in the eutrophic lake, which was estimated using data obtained in the eutrophic lake, was 117 microg/m2 yr, about 72% of which was attributed to the sedimentation corresponding to spring bloom phytoplankton deposition in late May to mid-June. The high sediment trap flux of HCHs in the eutrophic lake was related to serious local contamination.     

Organic compounds and trace metals of anthropogenic origin in sediments from Montego Bay,Jamaica: assessment of sources and distribution pathways

Surface sediments throughout Montego Bay, Jamaica were collected in 1995 and analyzed for their trace metal and trace organic contaminant content. A variety of trace metals, petroleum hydrocarbons, polycyclic aromatic hydrocarbons, coprostanol as well as chlorinated hydrocarbons such as pesticides and polychlorinated biphenyls were detected and provide evidence for several anthropogenic inputs to the bay. Two main sources of these chemicals are the Montego River and the North Gully, the latter being more significant. Particle-associated pollutants were found to be distributed along the Montego River plume, as well as being transported by the prevailing water currents to the South-Western sections of the bay, probably through re-suspension of enriched fine sediments from the North Gully outfall area.     

PCBs in sediments of the Great Lakes--distribution and trends, homolog and chlorine patterns, and in situ degradation

A region-wide data analysis on polychlorinated biphenyls (PCBs) in the sediment of the Great Lakes reveals a total accumulation of approximately 300 ± 50 tonnes, representing a >30% reduction from the 1980s. Evidence of in situ degradation of sediment PCB was found, with estimated t_1/2 of 11 and 17 years, at two open water locations in Lake Ontario. The relative abundance of heavy homologs as well as para-chlorines decreases with increasing depth, while the opposite is true for medium and light homologs and ortho-chlorines. In Lake Michigan, the vertical pattern features enrichment of heavier congeners and reduction of ortho-chlorines in deeper sediment layers, opposite to the trend in Lake Ontario. PCBs decrease log-linearly with increasing latitude and longitude. Air deposition of PCBs to lake sediment decreases at about 0.077 ng cm⁻² yr⁻¹ per degree latitude (N) for the geographic region extending from the Great Lakes to within the Arctic Circle.