Leachate emissions of short- and long-chain per- and polyfluoralkyl substances (PFASs) from various Norwegian landfills.

Restrictions on the use of long-chain per- and polyfluoralkyl substances (PFASs) has led to substitutions with short-chain PFASs. This study investigated the presence of four short-chain PFASs and twenty-four long-chain PFASs in leachate and sediment from ten Norwegian landfills, including one site in Svalbard, to assess whether short-chain PFASs are more dominant in leachate. PFASs were detected in all sites. Short-chain PFASs were major contributors to the total PFAS leachate concentrations in six of ten landfills, though not in Svalbard. In sediment, long-chain PFASs such as perfluorooctanesulfonate (PFOS) and PFOS-precursors were dominant. Short-chain PFAS leachate concentrations ranged from 68 to 6800 ng L-1 (mean: 980 ± 1800; median: 360 ng L-1), whereas long-chain concentrations ranged from 140 to 2900 ng L-1 (mean: 530 ± 730; median: 290 ng L-1). Sediment concentrations, which contained mainly long-chain PFASs, ranged from 8.5 to 120 µg kg-1 (mean: 47 ± 36; median: 41 µg kg-1). National release from Norwegian landfills to the environment was estimated to be 17 ± 29 kg per year (median: 6.3 kg per year), which is in the same range as national emissions from the US, China and Germany after normalizing the data to a per capita emission factor (3.2 ± 5.5 mg per person per year). Results from this study are compared with previous and current studies in other countries, indicating a general trend that short-chain PFASs are dominating over long-chain PFASs in landfill leachate emissions.

Norwegian study on microbial source tracking for water quality control and pollution removal in constructed wetland treating catchment run-off.

This study describes the first Norwegian microbial source tracking (MST) approach for water quality control and pollution removal from catchment run-off in a nature-based treatment system (NBTS) with a constructed wetland. The applied MST tools combined microbial analyses and molecular tests to detect and define the source(s) and dominant origin(s) of faecal water contamination. Faecal indicator bacteria Escherichia coli and host-specific Bacteroidales 16 s rRNA gene markers have been employed. The study revealed that the newly developed contribution profiling of faecal origin derived from the Bacteroidales DNA could quantitatively distinguish between human and non-human pollution origins. Further, the outcomes of the MST test have been compared with the results of both physicochemical analyses and tests of pharmaceutical and personal care products (PPCPs). A strong positive correlation was discovered between the human marker and PPCPs. Gabapentin was the most frequently detected compound and it showed the uppermost positive correlation with the human marker. The study demonstrated that the NBTS performs satisfactorily with the removal of E. coli but not PPCPs. Interestingly, the presence of PPCPs in the water samples was not correlated with high concentrations of E. coli. Neither has the latter an apparent correlation with the human marker.

Treating landfill gas hydrogen sulphide with mineral wool waste (MWW) and rod mill waste (RMW).

Hydrogen sulphide (H2S) gas is a major odorant at municipal landfills. The gas can be generated from different waste fractions, for example demolition waste containing gypsum based plaster board. The removal of H2S from landfill gas was investigated by filtering it through mineral wool waste products. The flow of gas varied from 0.3 l/min to 3.0 l/min. The gas was typical for landfill gas with a mean H2S concentration of ca. 4500 ppm. The results show that the sulphide gas can effectively be removed by mineral wool waste products. The ratios of the estimated potential for sulphide precipitation were 19:1 for rod mill waste (RMW) and mineral wool waste (MWW). A filter consisting of a mixture of MWW and RMW, with a vertical perforated gas tube through the center of filter material and with a downward gas flow, removed 98% of the sulfide gas over a period of 80 days. A downward gas flow was more efficient in contacting the filter materials. Mineral wool waste products are effective in removing hydrogen sulphide from landfill gas given an adequate contact time and water content in the filter material. Based on the estimated sulphide removal potential of mineral wool and rod mill waste of 14 g/kg and 261 g/kg, and assuming an average sulphide gas concentration of 4500 ppm, the removal capacity in the filter materials has been estimated to last between 11 and 308 days. At the studied location the experimental gas flow was 100 times less than the actual gas flow. We believe that the system described here can be upscaled in order to treat this gas flow.

Tracing solid waste leachate in groundwater using δ13 C from dissolved inorganic carbon.

Tracers can be used to monitor emissions of leachate from landfills in order to detect hydrological pathways and to evaluate environmental pollution. We investigated the stable carbon isotope ratio (δ(13)C-Σ CO (2)) in dissolved inorganic carbon and tritium ((3)H) in water, in addition to the tracers of pollution commonly found in relatively high concentrations in leachate, such as chloride (Cl), organic matter (COD), nitrogen (total and NH(4)-N), iron (Fe), electrical conductivity (EC) and pH. The sampling was performed at seven landfills in the south-eastern part of Norway during a period of 5 years. The objective was to evaluate the potential for tracing leachate in the environment with emphasis on groundwater pollution. By measuring the δ(13)C-Σ CO (2) in leachates, groundwaters and surface waters, the influence of leachate can be identified. The value of δ(13)C-Σ CO (2) varied from-5.5 to 25.9 ‰ in leachate, from-25.4 to 14.7 ‰ in groundwater and from-19.7 to-13.1 ‰ in creeks. A comparison of the carbon isotope ratio with COD, EC and the concentrations of total and NH (4)-N, Cl and Fe showed that δ(13)C-Σ CO (2) is a good tracer for leachate due to higher sensitivity compared to other parameters. The mean concentrations of all the studied parameters were higher in the leachate samples; however, only the carbon isotope ratio showed significant differences between all the groups with strong and middle pollution and samples with low pollution, showing that it can be used as a convenient tracer for leachate in groundwater and surface water. The carbon isotope ratio showed strong correlation between nitrogen, EC and bicarbonate, but not with pH. Tritium was only sporadically found in measureable concentrations and is not considered as a suitable tracer at the sampled locations.

Pesticide runoff from greenhouse production.

A research has been undertaken studying pesticide residues in water from greenhouses and the use of soils and filter materials to reduce such losses. The pesticides detected in water samples collected downstream greenhouses include 9 fungicides, 5 herbicides and 4 insecticides. 10 compounds from flower and vegetable productions were frequently found to exceed environmental risk levels, and with a few exceptions the compounds were found in higher concentrations than those typically found in agricultural runoff. Some compounds were found in high concentrations (>1 microg/l) in undiluted runoff from greenhouses producing vegetables. Nutrient concentrations in the runoff were also sporadically very high, with phosphorous values varying between 0.85 and 7.4 mg P/l, and nitrogen values between 7.5 and 41.4 mg N/l. Undiluted runoff from the productions showed values of 60 mg P/l and 300 mg N/l. High values of pesticides correlated with high values of nutrients, especially P. Column experiments using a sandy agricultural soil and stock solutions of non-polar and slightly polar pesticides mixed with a complex binder and nutrients showed a significant reduction for nearly all of the compounds used, indicating that transport through soil will reduce the concentrations of the studied pesticides. The pesticide adsorption capacity of the filter materials pine bark, peat, Sphagnum moss, compost, oat straw, ferrous sand and clay soil were tested in batch and column experiments. Adsorption were studied contacting the filter materials with aqueous solutions containing greenhouse production pesticides. The batch experiments showed that pine bark and peat, both combining a high content of organic matter with a low ph, provided the highest adsorption for most of the tested pesticides. Sphagnum moss, compost and oat straw also showed high adsorption for most of the pesticides, while the mineral filters provided the lowest adsorption (30-55%). Further column experiments confirmed these results, displaying the best removal efficiency in the organic materials, varying from 200 microg/g in compost, to 500 microg/g in moss, straw and pine bark.

Sensitivity analysis of pesticides contaminating groundwater by applying probability and transport methods.

The use of pesticides is a potential threat to local groundwater. Once groundwater is contaminated, it is very difficult to clean. Thus, it is of importance to assess the risk of contaminating local groundwater at an early stage when pesticides are found in soils. This knowledge will also help in remediation strategies. Traditional methods of deterministic analysis cannot explicitly account for the sometimes large uncertainties that exist at this stage in the work, whereas probabilistic analyses are better suited for dealing with these problems. In this paper, we have combined contaminant transport with a 1st-order reliability approach. Pesticide concentrations in soil have been studied to estimate the probability of failure--that is, of pesticides exceeding established critical levels in groundwater. Results indict that failure probability increases rapidly within a certain range of pesticide concentrations in soil for different critical levels. In given aquifer conditions and contaminants, probabilities of contaminants exceeding particular critical levels can easily be obtained according to various water usage scenarios. The distribution of importance factors among variables indicates the contribution their relative weights make to the failure probability. Hence, authorities can easily form sensitivity factors to take action and reduce the risk of contaminating the groundwater.

Halogenated compounds, PCB and pesticides in landfill leachate, downstream lake sediments and fish.

Two environmental sampling campaigns have been conducted in order to study the diffusion of selected pollutants from municipal solid waste landfills. The first campaign included the freshwater fish species pike, perch and roach, sampled by electrofishing, the second campaign included sampling of leachate, groundwater, sediments and fish. The analyses included chlorinated and brominated chemicals and pesticides, in addition to Hg. The study also included a compilation of Norwegian leachate data. Brominated compounds occurred in leachate between 0.02-11.1 microg/L, PCB from 0.01-3.1 microg/L, pesticides from 0.5-110 microg/L, and Hg from 0.005-62 microg/L. In the first campaign the fish samples contained chlorinated aromatics in concentrations between 25-162 microg/kg lipid, PBDE from 44 to almost 21000 microg/kg, HCH from 18 to 30 microg/kg, DDT between 152 to almost 27000 microg/kg and PCB from 89 to 36501 microg/kg. The highest concentrations were found at location 5, especially in pike samples. In the second campaign, measured concentrations were lower. The sediment samples showed low values of Hg, and no traces of pesticides. The content of Hg in the fish samples was low. The content of PCB in the fish samples was significantly higher than previous measurements and varied between 570-930 microg/kg wet weight. The fish samples contained DDE in concentrations of 20-190 microg/kg WW, levelling with previous studies. The levels of brominated compounds were lower in campaign two than in the first one, varying between < 0.03 to 33 microg/kg dry matter in the sediments, from 0.03 to 239 microg/L in groundwater, from < 0.03 to 5.1 in leachate, and between < 0.03 to 31 microg/kg wet weight in fish samples.

Metal oxides remove hydrogen sulfide from landfill gas produced from waste mixed with plaster board under wet conditions.

Hydrogen sulfide (H2S) is a major odorant in landfills. We have studied H2S production from landfill residual waste with and without sulfur-containing plaster board, including the influence of the water content in the waste. The laboratory experiments were conducted in 30-L polyethylene containers with a controlled water level. We also studied how different materials removed H2S in reactive layers on top of the waste. The organic waste produced H2S in concentrations of up to 40 parts per million (ppm) over a period of 80 days. When plaster board was added, the H2S concentration increased to 800 ppm after a lag period of approximately 40 days with a high water level, and to approximately 100 ppm after 50 days with a low water level. The methane (CH4) concentration in the initial experiment was between 5 and 70% after 80 days. The CH4 concentration in the second experiment increased to nearly 70% in the container with a high water level, slowly declining to approximately 60% between days 20 and 60. The CH4 concentrations during the experiments resembled normal landfill concentrations. Metallic filter materials were very efficient in removing H2S, whereas organic filter materials showed poor H2S removal.

Occurrence of carbon monoxide during organic waste degradation.

The concentrations of carbon monoxide (CO) and other gases were measured in the emissions from solid waste degradation under aerobic and anaerobic conditions during laboratory and field investigations. The emissions were measured as room temperature headspace gas concentrations in reactors of 1, 30, and 150 L, as well as sucked gas concentrations from windrow composting piles and a biocell, under field conditions. The aerobic composting laboratory experiments consisted of treatments with and without lime. The CO concentrations measured during anaerobic conditions varied from 0 to 3000 ppm, the average being 23 ppm, increasing to 133 ppm when methane (CH4) concentrations were low. The mean/maximum CO concentrations during the aerobic degradation in the 2-L reactor were 101/194 ppm without lime, 486/2022 ppm with lime, and 275/980 ppm in the 150-L reactors. The presence of CO during the aerobic composting followed a rapid decline in O2 concentrations Significantly higher CO concentrations were obtained when the aerobic degradation was amended with lime, probably because of a more extreme depletion of oxygen. The mean/maximum CO concentrations under field conditions during aerobic composting were 95/1000 ppm. The CO concentrations from the anaerobic biocell varied from 20 to 160 ppm. The hydrogen sulfide concentrations reached almost 1200 ppm during the anaerobic degradation and 67 ppm during the composting experiments.

Indications of hormonally active substances in municipal solid waste leachate: mobilization and effect studies from Sweden and Norway.

Several species of fish from a freshwater lake downstream a landfill in central Sweden have been found to be exposed to specific endocrine active substances (EAS), possibly able to interact with important functions in the synthesis of steroids and thereby disrupting a normal development of the gonad. A preliminary study of 7 streams and lakes in Norway showed that female perch have a significant reduction in gonad somatic index (GSI) with fish length and weight at one location. This can be an indication of disturbance due to exposure of hormonally active agents over time. Only 2 locations showed significantly difference in GSI and liver somatic index (LSI). Possible explanations can be that the necessary combination between exposure and exposed is exclusive and does not apply in general, or that the effects are masked due to other exposures such as e.g., nutrient, organic or other chemicals, physical or biological loads. The number of sampled locations is, however, too limited to be conclusive. Liver samples are being analyzed for organic pollutants, but these analyses were not ready at the time of publication. A previous study of leachate and sediment samples indicated the presence of several organic pollutants and compounds known to be hormonally active. Investigations of extracts from sediment samples from one of the exposed lake in Sweden showed the presence of both naturally occurring and xenophobic organic compounds. In samples extracted with a base-neutral extraction the compounds 1,1 sulfonyl-bis(4-chlorobenzene) and bis-2-etylhexyl-phtalate were detected. The high lipid affinity of the phtalate correlates with the finding of the compound in the high organic content layer of 20-40 cm in the exposed sediment. Pesticide residues were not found in the samples.