Background, aim, and scope Lungs are permanently and simultaneously challenged by airborne microorganisms and airborne pollutants. Temporal increase of airborne particulate matter (APM), a potential carrier for extractable organic matter (EOM), degrades the situation of pulmonary patients. The Ah receptor (AhR) has been described as an important factor influencing the immunological challenge by viral infections. Molecular mechanisms underlying epidemiological observations are not well understood. Cytokine secretion (IL-6, IL-8, and TGF-β) from human bronchial epithelial cells (Beas2B) was determined as an indicator for immune responses upon co-stimulation with an artificial analog of viral dsRNA [polyinosinic/polycytidylic acid, (PIC)] and EOM of Standard Reference Material 1649a (SRM). Since polycyclic aromatic hydrocarbons are major components of APM usually acting via the AhR, particular focus was on AhR involvement. Materials and methods Cytokine secretion was demonstrated by enzyme-linked immunosorbent assay. To mimic the activation of organic matter during contact of particles with the human lung, Soxhlet extraction of SRM was performed. In some experiments, the AhR was blocked by α-naphthoflavone. Results Microbial stimulation (PIC) induced Beas2B cytokine release, whereas isolated exposure to EOM of APM did not. Co-stimulation with EOM and PIC increased IL-8 secretion, whereas neither IL-6 nor TGF-β was affected. Blocking of the AhR suppressed the release of IL-8. Discussion Organic compounds adsorbed on airborne particulate matter influence the cytokine secretion of lung epithelial cells induced by pathogen-associated molecular patterns. Recommendations and perspectives Further investigation of these observations is required to understand the molecular mechanisms underlying adverse health effects of APM reported in epidemiological studies.

Introduction From the metallurgic industry zone of Dambovita County, we harvested and analyzed seven herbaceous plants species (Lolium perenne, Festuca pratensis, Stipa capillata, Agrostis alba, Cynodon dactylon, Luzula campestris, and Agrostis tenuis) to establish the heavy metal accumulation levels in these species. Materials and method The heavy metal contents (for Cr, Mn, Zn, Sr, Cu, Ba, and Sn) were determined by analyzing the dry matter with an inductively coupled plasma-atomic emission spectrometer. This method has detection limits of 0.4-0.6 mg/kg for the analyzed metals. The heavy metal concentrations in plants harvested from the industrial area are in milligram per kilogram of dry matter and ranged from 10.03 to 191.98 mg/kg of dry matter for Cr, 165.89 to 1,103.92 mg/kg of dry matter for Mn, 62.09 to 921.67 mg/kg of dry matter for Zn, 29.21 to 50.12 mg/kg of dry matter for Sr, 0.99 to 113.83 mg/kg of dry matter for Cu, 58.66 to 133.51 mg/kg of dry matter for Ba, and 8.38 to 276.44 mg/kg of dry matter for Sn. The heavy metal accumulation levels in the studied species of plants were calculated by the rapport between the concentration level of the metal in plant samples and the level of the same metal in the soil, near the radicular system for each species of plants. Results The highest accumulation levels were found in A. alba for Cr (267.69%); in L. perenne for Mn (51.45%), Sr (114.35%), and Ba (60.81%); and in C. dactylon for Zn (136.62%), Cu (97.65%), and F. pratensis for Sn (704.00%).

Background, aim and scope Chlormequat (Cq) is a plant growth regulator used throughout the world. Despite indications of possible effects of Cq on mammalian health and fertility, little is known about its fate and transport in subsurface environments. The aim of this study was to determine the fate of Cq in three Danish subsurface environments, in particular with respect to retardation of Cq in the A and B horizons and the risk of leaching to the aquatic environment. The study combines laboratory fate studies of Cq sorption and dissipation with field scale monitoring of the concentration of Cq in the subsurface environment, including artificial drains. Materials and methods For the laboratory studies, soil was sampled from the A and B horizons at three Danish field research stations—two clayey till sites and one coarse sandy site. Adsorption and desorption were described by means of the distribution coefficient (K d) and the Freundlich adsorption coefficient (K F,ads). The dissipation rate was estimated using soil sampled from the A horizon at the three sites. Half life (DT₅₀) was calculated by approximation to first-order kinetics. A total of 282 water samples were collected at the sites under the field monitoring study— groundwater from shallow monitoring screens located 1.5-4.5 m b.g.s. at all three sites as well as drainage water from the two clayey sites and porewater from suction cups at the sandy site, in both cases from 1 m b.g.s. The samples were analysed using LC-MS/MS. The field monitoring study was supported by hydrological modelling, which provided an overall water balance and a description of soil water dynamics in the vadose zone. Results The DT₅₀ of Cq from the A horizon ranged from 21 to 61 days. The Cq concentration-dependant distribution coefficient (K d) ranged from 2 to 566 cm³/g (median 18 cm³/g), and was lowest in the sandy soil (both the A and B horizons). The K F,ads ranged from 3 to 23 (µg¹ ⁻ ¹/n (cm³)¹/n g⁻¹) with the exponent (1/n) ranging from 0.44 to 0.87, and was lowest in the soil from the sandy site. Desorption of Cq was very low for the soil types investigated (<10%w). Cq in concentrations exceeding the detection limit (0.01 µg/L) was only found in two of the 282 water samples, the highest concentration being 0.017 µg/L. Discussion That sorption was highest in the clayey till soils is attributable to the composition of the soil, the soil clay and iron content being the main determinant of Cq sorption in both the A and B horizons of the subsurface environment. Cq was not detected in concentrations exceeding the detection limit in either the groundwater or the porewater at the sandy site. The only two samples in which Cq was detected were drainage water samples from the two clayey till sites. The presence of Cq here was probably attributable to the hydrogeological setting as water flow at the two clayey till sites is dominated by macropore flow and less by the flow in the low permeability matrix. In contrast, water flow at the sandy site is dominated by matrix flow in the high permeability matrix, with negligible macropore flow. Given the characteristics of these field sites, Cq adsorption and desorption can be expected to be controlled by the clay composition and content and the iron content. Combining these observations with the findings of the sorption and dissipation studies indicates that the key determinant of Cq retardation and fate in the soil is sorption characteristics and bioavailability. Conclusions The leaching risk of Cq was negligible at the clayey till and sandy sites investigated. The adsorption and desorption experiments indicated that absorption of Cq was high at all three sites, in particular at the clayey till sites, and that desorption was generally very limited. The study indicates that leaching of Cq to the groundwater is hindered by sorption and dissipation. The detection of Cq in drainage water at the clayey till sites and the evidence for rapid transport through macropores indicate that heavy precipitation events may cause pulses of Cq. Recommendations and perspectives The present study is the first to indicate that the risk of Cq leaching to the groundwater and surface water is low. Prior to any generalisation of the present results, the fate of Cq needs to be studied in other soil types, application regimes and climatic conditions to determine the Cq retardation capacity of the soils. The study identifies bioavailability and heavy precipitation events as important factors when assessing the risk of Cq contamination of the aquatic environment. The possible effects of future climate change need to be considered when assessing whether or not Cq poses an environmental risk.

Introduction In the present work, we explored the kinetics of dichlorvos (2,2-dichlorvinyl dimethyl phosphate, DDVP) decay through UV-A light-induced TiO₂ photocatalysis at pH 4 and 9, and the formation of degradation intermediates and final products under specific experimental conditions. Experimental observations and theoretical considerations allowed us to suggest the degradation mechanism of DDVP by the UV/TiO₂ process in aqueous solution. Methods The irradiation experiments were carried out in a photoreactor using a 228-W medium-pressure Hg vapor lamp. The concentration of DDVP, phosphate ion and formaldehyde as reaction intermediate, are determined spectrophotometrically. Chloride ion concentration was measured potentiometrically. Results The photocatalytic degradation rate of dichlorvos (DDVP) under UV irradiation (360-380 nm) was optimized with respect to the flow rate of O₂ gas sparged into the solution and photocatalyst concentration for a constant dichlorvos concentration (1.66×10⁻⁴ M) at pH 4. Kinetic data were obtained at pH 4 and pH 9 for dichlorvos and the inorganic species released through its photo-induced degradation. The proposed mechanism which assumes the formation of some toxic intermediates resistant to mineralization is supported by theoretical calculations and the observed inorganic mass balances. Conclusions The calculated pseudo-first-order rate constants were dependent on the dissolved oxygen level at low O₂ flow rate, but somewhat independent on the initial pH. The decrease of pH during the irradiation suggests the formation of organic acids. The presence of organic intermediates was confirmed also by TOC measurements. A plausible reaction mechanism of DDVP degradation through the UV-A/TiO₂ process was proposed.

Background, aim and scope The paper presents concentrations of trace elements in blood of homebred animals (cows and sheep) from Southern Serbia (Bujanovac) and the contents of natural and anthropogenic radionuclides and some heavy metals in feed. The region of Southern Serbia was exposed to contamination by depleted uranium ammunition during NATO attacks in 1999 and therefore, is of great concern to environmental pollution and human and animal health. Materials and methods Conventional instrumental and epithermal neutron activation analyses are used to measure trace elements in cow and sheep blood samples collected randomly at six locations in the region of Bujanovac (village of Borovac) in the spring of 2005. Samples of feed (grass and crops: corn, wheat and oats), collected on the same locations (households), are analysed for the contents of radionuclides on an HPGe detector (Ortec, relative efficiency 23%) by standard gamma spectrometry. The content of Hg, Pb and Cd in feed is determined by standard atomic absorption spectrometry on the VarianSpectra220/ThermoSolar GFS97 spectrometer. Results Concentrations of 29 elements (Na, Al (P), Cl, K, Sc, Cr, Mn, Ni, Fe, Co, Zn, Se, As, Br, Sr, Rb, Sb, In, I, Ba, Cs, La, Nd, Eu, Sm, Tb, Hf, Ta and Th) are determined in blood of the examined animals. In feeds, natural ⁴⁰K is found in all of the samples, cosmogenic ⁷Be and fission product ¹³⁷Cs are detected only in the grass samples, while heavy metals Hg, Cd and Pb are found in the range of 0.01-0.02, 0.84-1.15 and 0.74-7.34 mg/kg, respectively. Calculated soil-to-blood transfer factors are in a wide range of 8·10⁻⁶ to 64, as a result of varying significance of the elements in animal metabolism and feeding habits. Discussion The results of trace elements' concentrations in animal blood are in good agreement with available data for K, Ni, Zn, Se and Rb. Higher Br concentrations in animal blood are most probably caused by large biomass burning events during blood sampling. Very low concentration of Fe in cows and sheep confirms the results of previous biochemical studies on animal anaemia in the region. High concentration of As correlates with geochemical peculiarities of the Balkans and is also likely influenced by the use of pesticides in the agricultural production. For some of the elements (La, Nd, Eu, Sm, Tb, Sb, Hf, Ta, Th, In, Ba, Sr, Sc and Cs), there are few or no literature data. Therefore, some of the presented data are significant not only for the country and the region, but on a wider scale. Activities of natural radionuclides in feeds are within the average values reported for the region, while the activities of ²¹⁰Pb and ²³⁵/²³⁸U are below the limit of detection. This is in accordance with previous investigations showing no widespread contamination by depleted uranium in the area. Contents of Hg and Pb in feeds are below the nationally permissible levels, unlike the content of Cd which exceeds it, probably caused by the use of phosphate fertilisers and fossil fuel combustion in the area. Conclusions In general, the concentrations of trace elements in blood of homebred cows and sheep are in good agreement with reference materials, available literature data and the results of previous studies in the area. The exceptions are Fe, As and Br. The contents of natural and anthropogenic radionuclides in feeds are within the expected levels, and there are no signs of contamination by depleted uranium or other fission products. Apart from Cd, there are no signs of pollution by heavy metals in feeds. The highly sensitive method of instrumental neutron activation analysis provides data on the concentration of some elements in animal blood not previously reported for the region and elsewhere. Recommendations and perspectives The presented study is a part of the long term ongoing project on the health risk assessment on animals and humans in the region. The collected data is intended to provide a base for the animal and human risk assessment as well as an estimate of the general pollution status of the environment in the region. Since some of the investigated elements are classified as important trace elements for livestock, the results could also be used to balance and improve the animal diet and thus, improve the growth and reproduction rate.

Background, aim, and scope Current Australian legislation permits the beneficial application of grease trap waste (GTW) to agricultural soil, viewing it as a beneficial source of organic matter and soil conditioner containing no/low amounts of metals or pathogenic organisms. However, little is known about the influence of GTW on soil bacterial community. A field experiment was established at Menangle in south western Sydney in Australia to quantitatively assess the impacts of different types (GTW CO and GTW CL) and amounts of GTW application on the soil bacterial community and diversity. Furthermore, a municipal solid waste (MSW) compost was simultaneously examined to compare against the other organic wastes. Knowledge about the shifts in microbial community structure and diversity following the applications of organic wastes could help to evaluate the ecological consequences on the soil and thus to develop sound regulatory guidelines for the beneficial reuse of organic wastes in agricultural lands. Materials and methods Soil samples were collected from recycled organics plots treated with different types and quantity of organic wastes. The field experimental treatments included control (CK, without application of any organic wastes), low amount of GTW CO (COL), GTW CL (CLL), and MSW (ML), and high amounts of GTW CO (COH), GTW CL (CLH), and MSW compost (MH). Microbial DNA was extracted from soil samples and the 16S rRNA genes were polymerase chain reaction (PCR)-amplified. The PCR products were analyzed by denaturing gradient gel electrophoresis (DGGE), cloning, and sequencing. The bacterial community structures and diversity were assessed using the DGGE profiles and clone libraries constructed from the excised DGGE bands. Results DGGE-based analyses showed that application of the GTW CO, regardless of the amount applied, had significant negative effects on soil bacterial genotypic diversity and community structure compared with the control, while the applications of other organic wastes including the GTW CL and MSW had no clear effects. The effects of the rate of organic waste application on soil bacterial community characteristics varied with the types of organic wastes applied. Sequence-based analyses of 126 clones indicated that Proteobacteria (53.2%) was the dominant taxa at the experimental site, followed by Actinobacteria (9.5%), Bacteroidetes (7.9%), Firmicutes (7.9%), Gemmatimonadetes (5.6%), Chloroflexi (2.4%), Acidobacteria (1.6%) and the unclassified group (11.9%). In the COH treatment, Acidobacteria, Bacteroidetes, and Gemmatimonadetes were not detected; the percentages of Firmicutes, Proteobacteria, and Actinobacteria in the COH treatment were significantly different from those in CK. There is a significant positive correlation (r = 0.71, p = 0.002) between the C/N ratio of organic wastes and the bacterial genotypic communities. Discussion Both the type and the amount of GTW applied affected soil bacterial genotypic diversity and community structure. The different effects of various types of organic wastes on soil bacterial characteristics may be predicted by the differences in specific properties of organic wastes such as C/N ratio, as evidenced by the strong and significant positive relationship between the bacterial community distance and the environmental distance of C/N ratio. This also indicates that the C/N ratio of GTW applied can be a major driver for the shift in the soil bacterial community. Conclusions Our results revealed that the effects of organic wastes on soil bacterial communities varied with the types of organic wastes, and depending on the rate of application. Application of the GTW CO led to significant shifts in soil bacterial community diversity and structure. The effects of different types of organic wastes on the soil bacterial characteristics can be predicted by the differences of specific properties of organic wastes, such as the C/N ratio. Sequence-based analyses of 126 clones indicated that Proteobacteria was the dominant taxa at the experimental site. Recommendations and perspectives Our results have important implications for developing sound regulatory guidelines for the beneficial reuse of organic wastes, indicating that GTW CO and similar organic waste treatments may not be suitable for application in agricultural soils due to its significant negative effect on soil bacterial community.

Background, aim, and scope Passive air sampling survey of the Central and Eastern Europe was initiated in 2006. This paper presents data on toxic organic compounds such as polychlorinated biphenyls (PCB 28, 52, 101, 118, 153, 138, and 180), hexachlorobenzene (HCB), pentachlorobenzene (PeCB), hexachlorocyclohexane compounds (α-HCH, β-HCH,γ-HCH, δ-HCH), and dichloro-diphenyl-trichloroethane (DDT) compounds (p,p′DDE, p,p′DDD, p,p′DDT, o,p′DDE, o,p′DDD, and o,p′DDT) determined in ambient air and soil samples collected at Estonian monitoring stations. Materials and methods Ambient air and soil samples were collected in five sites in northern Estonia. Passive air samplers were deployed four times over 4-week periods covering the period April-August 2006. Samples were analyzed using gas chromatography-electron capture detector (HP 5890) supplied with a Quadrex fused silica column 5% Ph for organochlorine pesticides (OCPs). Local ground-boundary wind field was modeled for each monitoring station and sampling period on the basis of observed wind data from the nearest meteorological station with a high quality of time series and compared with upper air (at 850- and 500-hPa level) data from Tallinn-Harku aerological station. Results Median levels of PCB at Estonian stations varied between 3 and 9 ng/filter, although the maximum in Kohtla-Järve reached as high as 28 ng/filter. Sampling rates about 3.5 m³/day were determined by empirical measurements, making approximately 100 m³ for a 28-day sampling cycle. In general, OCP levels in soil were at the limit of detection, except Tallinn site and Muuga Port affected mainly by local sources. However, the atmospheric PCB concentrations are in agreement with the soil analyses where highest PCB levels were found in the soil sample for Tallinn (12.0 ng/g dry weight). For HCB, the atmospheric distribution was quite uniform, with the background levels sometimes higher than the urban ones. HCB and PeCB concentrations were very low in May and June when meridional airflow from the southern sector dominated, and concentrations were slightly higher in July and August, most probably due to revolatilization of adsorbed HCB (with PeCB impurities) from former industrial applications during the summer month and possibly enhanced by forest fires in Russia. Also, the highest summary HCH and DDT levels (63.5 and 2.5 ng/filter, respectively) in Estonian monitoring stations were determined at the end of July and beginning of August when the ground-boundary wind direction was from NE with relatively high speed (4-7 m/s). The highest DDT levels in ambient air (3.5 ng/filter) were determined in the spring samples. For DDT and HCH, long-range atmospheric transport clearly dominates persistent OCP, atmospheric input to Estonia as well as for the Scandinavian countries. The DDE/DDT ratio was >1, indicating no fresh input. Discussion The passive air sampling demonstrates uniform distribution of OCPs. In the regional context, there is no indication of increased levels of concentrations of OCPs in the industrial Northeast Estonia where the oil shale processing causes certain pollution impacts. Though the passive sampling does not apply for monitoring of short-term fluxes, the method is capable of reflecting background levels in long-term prospective for potential effect on human health due to long-term exposition of OCPs. Conclusions PCB and its congeners, HCB, PeCB, HCH, and DDT were very low in Estonia. None of the persistent organochlorine pesticides have ever been produced in Estonia, and as of today, all old OCP stocks in the country have been destroyed. Highest concentrations could be expected in March and April when southwestern airflow is still strong and dominant, but air humidity is lower and deposition takes place far from the place of origin of OCPs. In summer, the share of locally formed organic compounds increases and deposition depends strongly on weather conditions. In some cases in Tallinn and Muuga where local anthropogenic impact occurs, HCB and PeCB stem from revolatilization of industrial application. Recommendations and perspectives The passive air sampling could be employed more widely to explore long-term human exposure to OCP deposition and assess potential health risks. The survey based on passive air sampling could be extended from Central and Eastern Europe to other European regions to get methodically adjusted cross-European data coverage. Based on the results of the survey, the Lahemaa reference station is a feasible option to represent background monitoring of persistent organic pollutants.

Background, aim, and scope Zinc is an essential micronutrient element but its concentrations found in contaminated soils frequently exceed those required by the plant and soil organisms, and thus create danger to animal and human health. Phytoremediation is a technique, often employed in remediation of contaminated soils, which aims to remove heavy metals or other contaminants from soils or waters using plants. Arabidopsis (A.) halleri ssp. gemmifera is a plant recently found to be grown vigorously in heavy metal contaminated areas of Japan and it contained remarkably high amount of heavy metals in its shoots. However, the magnitude of Zn accumulation and tolerance in A. halleri ssp. gemmifera need to be investigated for its use as a phytoremediation plant. Materials and methods A. halleri ssp. gemmifera was grown for 3 weeks into half-strength nutrient solution with Zn (as ZnSO₄) levels ranging from 0.2 to 2,000 µM. The harvested plants were separated into shoots and roots, dried in the oven, and ground. The plant tissue was digested with nitric-perchloric acid, and the Zn concentration in the digested solution was measured by atomic absorption spectrophotometer. Results and discussion The results showed no reduction in shoot and root dry weight when plants were grown at 0.2 to 2,000 µM Zn in the solution. The highest Zn concentration measured in the shoots was 26,400 mg kg⁻¹ at 1,000 µM Zn, while in the roots, it was 71,000 mg kg⁻¹ at 2,000 µM Zn treatment. Similar to the Zn concentration in plant parts, maximum Zn accumulation of 62 mg plant⁻¹ in the shoots and 22 mg plant⁻¹ in the roots was obtained at 1,000 and 2,000 µM Zn in the solution. The percentage of Zn translocation in shoot varied from 69% to 90% of the total Zn, indicating that the shoot was the major sink of Zn accumulation in this plant. Conclusions The results of this study indicate that the growth of A. halleri ssp. gemmifera was not affected by the Zn level of up to 2,000 µM in the nutrient solution. The concentration of Zn found in shoot indicated that A. halleri ssp. gemmifera has an extraordinary ability to tolerate and accumulate Zn and hence a good candidate for the phytoremediation of Zn-polluted soil. Recommendations and outlook Based on the results presented in this study and earlier hydroponics, and field study, A. halleri ssp. gemmifera seems to be a potential heavy metals hyperaccumulator, and could be recommended to use for phytoremediation of Cd- and Zn-contaminated soils.

Background, aim, and scope Mutagenic nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) have been known to arise in the environment through direct emissions from combustion sources and nitration of PAHs, primarily in the atmosphere. In the marine environment, PAHs are one of the classic anthropogenic organic pollutants, while nitrite (NO ₂ ⁻ ) is produced naturally via various biological processes like imbalance in nitrification/denitrification or eutrophication and subsequent oxygen depletion from an oversupply of nutrients. In this paper, we report the formation of PAH-DNA adducts in fish contaminated with PAHs and exposed to NO ₂ ⁻ in the ambient water. Electrospray ionization tandem mass spectrometric (ESI-MS/MS) analysis of the bile of the euryhaline fish Oreochromis mossambicus exposed simultaneously to field relevant sublethal concentrations of phenanthrene and NO ₂ ⁻ and collision-induced dissociation of selected ions revealed the presence of DNA-PAH adducts. The present study indicates that, although several high sensitivity techniques have been developed for the analysis of PAH derived DNA adducts, MS/MS has emerged as a powerful tool in the detection and structure elucidation of DNA adducts. Materials and methods Juvenile O. mossambicus from a local estuarine fish farm were used with increasing frequency for carcinogenicity testing and comparative cancer research. The fish were exposed to the alkylating agent phenanthrene in the presence of NO ₂ ⁻ . Composite untreated bile samples after dilution with methanol: water (1:1; v/v) were analyzed by ESI-MS. Results Several adducts could be evidenced in the bile by MS/MS. Deoxyadenosine/deoxyguanosine having a mass in the range of 450-650 amu is detected. In addition, a segment of modified dinucleotide with a mass that corresponds to a dimer consisting of a modified guanosine and a normal guanosine has also been identified in the bile. Discussion The formation of certain types of DNA adducts is a crucial step in the induction of cancer and a primary stage in mutagenesis. Phenanthrene injected by i.p. route led to the transformation of phenanthrene to N-formyl amino phenanthrene-N ⁶-deoxyadenosine adduct, whereas the fish co-exposed to phenanthrene and ambient nitrite metabolizes PAH to mono-, di- as well as trinitro derivatives, which then react with DNA leading to the formation of mainly modified guanosine and adenosine adducts. In the present investigation, dinitrophenanthrene diol epoxide (DNPDE) adduct with guanosine (m/z 587) seems to be the dominant adduct in the mixture, and its presence is shown first as a comparatively less stable adduct, which decomposes to give a more stable N² adduct (m/z 567). Conclusions MS/MS has proved to be useful in the rapid determination and discrimination of structurally different phenanthrene/derivatives DNA adducts in a complex mixture of fish bile co-exposed to phenanthrene and nitrite. However, the nature of metabolites formed is likely determined by the route of PAH administration, and there is a need to further define the early biochemical events of carcinogenesis in these species. Recommendations and perspectives DNA adduct analysis in fish bile offers a promising approach to study the risk of potentiation of anthropogenic chemicals into genotoxic compounds in the presence of nitrite in the marine environment. We believe this is the first report on the formation of DNA-phenanthrene adducts on co-exposure of the fish to PAH and nitrite.

Background, aim, and scope The Lower Mississippi River is a major transportation route for commercial goods and petroleum products produced and refined locally. Oil spills caused by vessel accidents and equipment failure at refineries are a serious threat to the drinking water supply of Southern Louisiana, as well as to the many natural, economic, and social resources supported by the river. Providing accurate trajectory modeling to contingency planners is critical to protecting the local environment. The majority of trajectory model results, assuming a uniform shoreline, show 60-70% of spilled oil can be retained. This study examines the impact of detailed shoreline mapping that captures spatial and temporal changes in shoreline type on oil spill trajectory modeling. Materials and methods Detailed shoreline maps based on recent remote sensing imagery were generated to identify spatial changes in shoreline. A hydrodynamic model of the 78 mile reach from Convent, Louisiana to West Pointe a la Hache was developed to obtain the stage levels and velocity fields of four river discharges. Based on river stage level, another layer was added to the shoreline maps, so that shoreline type was accurately represented at each river discharge, a feature not included in previous mapping. An oil spill trajectory model was then used to investigate the effect of implementing different re-floatation half-lives that correlate to the shoreline maps developed for this study at four river discharges. Results Detailed shoreline mapping showed the Lower Mississippi River has four major shoreline types each with different oil re-floatation half-lives: muddy clay, sand, low vegetation, and high vegetation. As flow rate changed, the shoreline spatial variability also changed, from 84% mud/sand and 16% vegetation at low flow rates to 4% mud and 96% vegetation at higher flow rates. At flow rates with large variability in shoreline type, the distribution of oil attached to the shore was significantly different from results of simulations that used a constant shoreline type and re-floatation half-life. Discussion At low flow rates, simulations with the detailed delineation of shoreline type predicted that ~30% of the oil would be beached/retained because the oil was able to travel further down the reach and interact with the shoreline in multiple locations. Simulations at the low flow rates with the existing shoreline mapping predicted approximately 65% of the oil would be retained as did all the simulations at the highest flow rates. At high flow rates, the oil interacted mostly with vegetation and results were very similar to those obtained with a single re-floatation half-life of 1 year. In addition to shoreline type, river geometry and the hydrodynamics were major factors influencing the distribution of oil along the river reach. Conclusions Shoreline re-floatation half-lives have a major impact on simulating the distribution of oil along the shore after a spill, especially in areas with a high variability of shoreline type as in the lower Mississippi River. Assigning the correct re-floatation half-life and retention capacity is only possible when shoreline types have been correctly identified. The maps developed for this study provided an important level of detail and incorporated the change in shoreline type with flow rate, resulting in more detailed trajectory modeling of the study reach. Recommendations and perspectives Shoreline maps should include as much detail about shoreline type as possible. When developing shoreline maps or environmental sensitivity assessments, the focus should include specific characteristics of the study area; using standardized maps or methods of assessment may leave out detail that could negatively impact modeling efforts. Finally, shoreline sensitivity to oiling is an important area of research that will benefit from an improved understanding of oil retention by vegetation.