Agricultural Source Pollution Research Articles

Variation and driving factors of nitrous oxide emissions from irrigated paddy field in the arid and semiarid region

Agricultural pollution source as Nitrous oxide (N2O) emission from irrigated paddy field as affected by overuse of chemical fertilizer application and flooding irrigation is the primary anthropogenic source of nitrogen (N) losses in the Ningxia irrigation district. The emissions variation and driving factors of N2O emission in the large irrigation districts needs much more investigation. A static chamber-gas chromatograph method was conducted to quantify N losses from a paddy field in Lingwu Farm during 2009–2010. Three nitrogen (N) treatments were conducted, including the conventional N application rate of 300 kg ha−1 (N300), the reducing N application rate of 240 kg ha−1 (N240) and control plot (N0). The N2O emissions due to combined effects of the fertilizer application and flood irrigation after winter dry follow was 2.86–3.27 kg ha−1 in N300. The flood irrigation at the beginning of the rice transplanting promotes N2O emissions due to nitrification–denitrification of a richer N source provided by the N fertilizer accumulation of soil NH4+ and NO3-. During the rice growth stage when the paddy field was submerged, N2O emission was very low while intermittent irrigation before tillering and the maturation stages, frequent alteration of dry and wet soil condition enhance N2O emission. The reducing N fertilizer application improved the recovery rate in rice and resulted in a less N2O emission from irrigated paddy field in the arid and semiarid region while keeping the rice yield.

Long-Term Monitoring of a Surface Flow Constructed Wetland Treating Agricultural Drainage Water in Northern Italy

Agricultural drainage water that has seeped into tile drainage systems can cause nitrogen and phosphorus pollution of the surface water bodies. Constructed wetlands (CWs) can help mitigate the effects of agricultural non-point sources of pollution and remove different pollutants from tile drainage water. In this study, hydrological and water quality data of a Northern Italian CW that has been treating agricultural drainage water since 2000 were considered to assess its ability to mitigate nitrogen and phosphorus pollution. The effects of such long-term operation on the nutrients and heavy metals that eventually accumulate in CW plants and sediments were also analysed. Since 2003, the CW has received different inflows with different nutrient loads due to several operation modes. However, on average, the outflow load has been 50% lower than the inflow one; thus, it can be said that the system has proved itself to be a viable option for tile drainage water treatment. It was found that the concentration of nitrogen and phosphorus in the plant tissues varied, whereas the nitrogen content of the soil increased more than 2.5 times. Heavy metals were found accumulated in the plant root systems and uniformly distributed throughout a 60 cm soil profile at levels suitable for private and public green areas, according to the Italian law

Simulation on Change Law of Runoff, Sediment and Non-point Source Nitrogen and Phosphorus Discharge under Different Land uses Based on SWAT Model: A Case Study of Er hai Lake Small Watershed

The Er yuan watershed of Er hai district is chosen as the research area, the law of runoff and sediment and non-point source nitrogen and phosphorus discharges under different land uses during 2001 to 2014 are simulated based on SWAT model. Results of simulation indicate that the order of total runoff yield of different land use type from high to low is grassland, paddy fields, dry land. Specifically, the order of surface runoff yield from high to low is paddy fields, dry land, grassland, the order of lateral runoff yield from high to low is paddy fields, dry land, grassland, the order of groundwater runoff yield from high to low is grassland, paddy fields, dry land. The orders of sediment and nitrogen and phosphorus yield per unit area of different land use type are the same, grassland> paddy fields> dry land. It can be seen, nitrogen and phosphorus discharges from paddy fields and dry land are the main sources of agricultural non-point pollution of the irrigated area. Therefore, reasonable field management measures which can decrease the discharge of nitrogen and phosphorus of paddy fields and dry land are the key to agricultural non-point source pollution prevention and control.

Climate Change Impacts on Nutrient Losses of Two Watersheds in the Great Lakes Region

Non-point sources (NPS) of agricultural chemical pollution are one major reason for the water quality degradation of the Great Lakes, which impacts millions of residents in the states and provinces that are bordering them. Future climate change will further impact water quality in both direct and indirect ways by influencing the hydrological cycle and processes of nutrient transportation and transformation, but studies are still rare. This study focuses on quantifying the impacts of climate change on nutrient (Nitrogen and Phosphorus) losses from the two small watersheds (Walworth watershed and Green Lake watershed) within the Great Lakes region. Analysis focused on changes through this century (comparing the nutrient loss prediction of three future periods from 2015 to 2099 with 30 years for each period against the historical nutrient estimation data from 1985 to 2008). The effects on total phosphorus and nitrate-nitrogen losses due to changes in precipitation quantity, intensity, and frequency, as well as air temperature, are evaluated for the two small watersheds, under three special report emission scenarios (SRES A2, A1B, B1). The newly developed Water Erosion Prediction Project-Water Quality (WEPP-WQ) model is utilized to simulate nutrient losses with downscaled and bias corrected future climate forcing from two General Circulation Models (GFDL, HadCM3). For each watershed, the observed runoff and nutrient loads are used to calibrate and validate the model before the application of the WEPP-WQ model to examine potential impacts from future climate change. Total phosphorus loss is projected to increase by 28% to 89% for the Green Lake watershed and 25% to 108% for the Walworth watershed mainly due to the combined effects of increase of precipitation quantity, extreme storm events in intensity and frequency, and air temperature. Nitrate-nitrogen losses are projected to increase by 1.1% to 38% for the Green Lake watershed and 8% to 95% for the Walworth watershed with the different major influencing factors in each future periods.

Statistical and Data Mining Techniques for Understanding Water Quality Profiles in a Mining-Affected River Basin

This article contains a multivariate analysis (MV), data mining (DM) techniques and water quality index (WQI) metrics which were applied to a water quality dataset from three water quality monitoring stations in the Petaquilla River Basin, Panama, to understand the environmental stress on the river and to assess the feasibility for drinking. Principal Components and Factor Analysis (PCA/FA), indicated that the factors which changed the quality of the water for the two seasons differed. During the low flow season, water quality showed to be influenced by turbidity (NTU) and total suspended solids (TSS). For the high flow season, main changes on water quality were characterized by an inverse relation of NTU and TSS with electrical conductivity (EC) and chlorides (Cl), followed by sources of agricultural pollution. To complement the MV analysis, DM techniques like cluster analysis (CA) and classification (CLA) was applied and to assess the quality of the water for drinking, a WQI.

Spatial–Temporal Analysis of the Relationships between Agricultural Production and Use of Agrochemicals in Eastern China and Related Environmental and Political Implications (Based on Decoupling Approach and LMDI Decomposition Analysis)

Agrochemical inputs such as chemical fertilizers and pesticides have been recognized as sources of agricultural non-point source pollution and are controlled in order to prevent further deterioration of water pollution. In consideration of the available and effective measures to improve agricultural output value in a long-term, the key to the adoption of reduction control on agrochemical inputs is to ensure the decoupling relationship of agrochemical inputs to agricultural economic growth and to find out the endogenous growth of agrochemical inputs. This paper analyzed the relationship of agrochemical input consumption and agricultural output value in Eastern China by the Topia decoupling model. Interestingly, the transformation of expansive negative decoupling—expansive coupling—weak decoupling—strong decoupling was exposed, which can be used as a theoretical support to the source reduction control on agricultural non-point source pollution. The source reduction can be influenced of three factors: area factor, agricultural productivity factor and efficiency factor, which were decomposed by applying a log-mean Divisia index (LMDI) method, and the efficiency factor can promote the slowing down of the increase of agrochemical input consumption, while the agricultural productivity factor was the main factor to increase agrochemical input consumption; the area factor was not obvious. In addition to that, the formulation and implementation of source reduction control policies was affected by the differences of the spatial framework in Eastern China, where the source reduction control in different regions would be used to move ahead (or to delay).

Assessing the environmental impact of pesticide use in banana cropping systems

In the French West Indies, high pest pressure on cropping systems has triggered high inputs of pesticides, especially in banana cropping systems. These pesticides then disperse in soil, ground and surface water, threatening ecosystem and human health. Reducing the environmental impact of banana cropping systems in this area requires i) predicting environmental states according to cropping systems evolution, ii) identifying key factors triggering pollution, and iii) proposing measures to reduce impact. Since farmers apply pesticides at the field scale while environmental impacts spring up at the watershed scale, multi-scale environmental impact assessments of pesticide use are required. Therefore, our work focuses on the characterization of i) pollutant input (type of molecule, quantity applied, frequency), ii) pollutant transfers, through hydrological modelling, and iii) environmental state through water quality measurements. Studies carried out at field scale, sub-watershed scale and watershed scale will be presented. They were located in Perou river catchment in Guadeloupe and Galion river catchment in Martinique. Results provide a wide overview of the main hydrological processes involved in pesticides transfers towards rivers in tropical volcanic catchments. However, those studies focused either on chlordecone, an old organochlorine, or cadusafos, a nematicide used 10 years ago in banana cropping systems. Recent measurements performed at the watershed scale showed herbicides applied in sugarcane fields and banana post-harvest fungicides to be among the main pollutants in these rivers. Consequently, long-term and multi-residue monitoring is required to understand the fate of the different molecules applied in fields taking account of cropping systems evolution over time. This will be further performed thanks to the set-up of the Observatory of agricultural-source pollution in the French West Indies (OPALE).

Distribution, bioavailability and probabilistic integrated ecological risk assessment of heavy metals in sediments from Honghu Lake, China

Abstract Heavy metals (Cr, Cu, Zn, Pb, Cd) concentrations and fractions in surface sediments from Honghu Lake were detected by an atomic absorption spectrophotometer and Simple Bioavailability Extraction Test (SBET) from 11 typical sites to explore their spatial distribution, bioavailability and sources. Results showed the mean Igeos and ecological risk degrees decreased in the order of Cd>Cu>Cr>Pb>Zn and Cd>Cu>Pb>Cr>Zn. The metals’ bioavailability estimated by SBET decreased in the general order of Cu>Pb>Cd>Zn>Cr. Under integrated consideration of metal enrichment, ecological risk and bioavailability, it obviously made the decision-makers confused to identify final priority pollutants and priority areas. Thus, a probabilistic integrated ecological risk assessment method (PIERA) was formulated based on the potential ecological risk index (PER), SBET and triangular fuzzy numbers for synthetically assessing metal enrichment, ecotoxicity and bioavailability. With the help of PIERA, Cd was finally regarded as the risk priority metal due to the integrated potential eco-risk of Cd made the average contribution of 86.4% to the integrated RIs. Moreover, the areas around S5 and S2 were regarded as the risk priority areas. The case application of PIERA revealed that this improved method is of a better resolving ability which scientifically supplies the integrated information of enrichment, bioavailability and systematic uncertainty for decision-makers compared with the other prevalent indexes (SQGs, Igeo, PER). The consequence of the Pearson correlation analysis, distribution analysis and field investigation indicated that Cd mainly originated from both non-point agricultural and industrial pollution sources.

Composition and Functional Specialists of the Gut Microbiota of Frogs Reflect Habitat Differences and Agricultural Activity.

The physiological impact of agricultural pollution, habitat disturbance, and food source variability on amphibian remains poorly understood. By comparing the composition and predicted functions of gut microbiota of two frog species from forest and farmland, we quantified the effects of the exogenous environment and endogenous filters on gut microbiota and the corresponding functions. However, compositional differences of the gut microbiota between the frog species were not detected, even when removing roughly 80–88% of the confounding effect produced by common and shared bacteria (i.e., generalists) and those taxa deemed too rare. The habitat effect accounted for 14.1% of the compositional difference of gut microbial specialists, but host and host × habitat effects were not significant. Similar trends of a significant habitat effect, at an even higher level (26.0%), for the physiological and metabolic functions of gut microbiota was predicted. A very obvious skewing of the relative abundance of functional groups toward farmland habitats reflects the highly diverse bacterial functions of farmland frogs, in particular related to pathogenic disease and pesticide degradation, which may be indication of poor adaptation or strong selective pressure against disease. These patterns reflect the impacts of agricultural activities on frogs and how such stresses may be applied in an unequal manner for different frog species.

Can integrative catchment management mitigate future water quality issues caused by climate change and socio-economic development?

Abstract. The design and evaluation of solutions for integrated surface water quality management requires an integrated modelling approach. Integrated models have to be comprehensive enough to cover the aspects relevant for management decisions, allowing for mapping of larger-scale processes such as climate change to the regional and local contexts. Besides this, models have to be sufficiently simple and fast to apply proper methods of uncertainty analysis, covering model structure deficits and error propagation through the chain of sub-models. Here, we present a new integrated catchment model satisfying both conditions. The conceptual iWaQa model was developed to support the integrated management of small streams. It can be used to predict traditional water quality parameters, such as nutrients and a wide set of organic micropollutants (plant and material protection products), by considering all major pollutant pathways in urban and agricultural environments. Due to its simplicity, the model allows for a full, propagative analysis of predictive uncertainty, including certain structural and input errors. The usefulness of the model is demonstrated by predicting future surface water quality in a small catchment with mixed land use in the Swiss Plateau. We consider climate change, population growth or decline, socio-economic development, and the implementation of management strategies to tackle urban and agricultural point and non-point sources of pollution. Our results indicate that input and model structure uncertainties are the most influential factors for certain water quality parameters. In these cases model uncertainty is already high for present conditions. Nevertheless, accounting for today's uncertainty makes management fairly robust to the foreseen range of potential changes in the next decades. The assessment of total predictive uncertainty allows for selecting management strategies that show small sensitivity to poorly known boundary conditions. The identification of important sources of uncertainty helps to guide future monitoring efforts and pinpoints key indicators, whose evolution should be closely followed to adapt management. The possible impact of climate change is clearly demonstrated by water quality substantially changing depending on single climate model chains. However, when all climate trajectories are combined, the human land use and management decisions have a larger influence on water quality against a time horizon of 2050 in the study.

A GIS-based LVF model for semiquantitative assessment of groundwater pollution risk: A case study in Shenyang, NE China

ABSTRACTGroundwater pollution risk assessment is a useful tool to prevent and control groundwater pollution, but its quantitative research is still relatively immature. In this study, a geographic information system based LVF model for a semiquantitative assessment of groundwater pollution risk is established, based on the groundwater pollution source load (L), groundwater vulnerability (V), and groundwater function value (F). Further, the pollution source load is characterized by seven specific pollution sources, the vulnerability is calculated by the modified DRASTIC method, and the groundwater function value is evaluated with the water quality and quantity. The model was used to assess the risk of shallow groundwater pollution in Shenyang city, Northeast China, with an area of 8,263 km2. The results show that highest risk areas account for 16.3% of the study area and are mainly distributed in the east of the study area. High risk areas are significantly affected by a shallow buried depth of groundwater and many types of harmful pollutants from industrial, agricultural, and domestic pollution sources. The evaluation results reflect the risk of groundwater pollution in the Shenyang area, which is relevant to the management and sustainable use of groundwater resources in the area.

Diffuse Pollution, Degraded Waters: emerging policy solutions

After decades of regulation and investment to reduce point source water pollution, OECD countries still face water quality challenges (e.g. eutrophication) from diffuse agricultural and urban sources of pollution, that is disperse pollution from surface runoff, soil filtration and atmospheric deposition. The relative lack of progress reflects the complexities of controlling multiple pollutants from multiple sources, their high spatial and temporal variability, associated transactions costs, and limited political acceptability of regulatory measures. This report outlines the water quality challenges facing OECD countries today, presents a range of policy instruments and innovative case studies of diffuse pollution control, and concludes with an integrated policy framework to tackle diffuse water pollution. An optimal approach will likely entail a mix of policy interventions reflecting the basic OECD principles of water quality management – pollution prevention, treatment at source, the polluter pays and beneficiary pays principles, equity, and policy coherence.This title belongs to OECD Report SeriesISBN: 9781780408781 (Print)ISBN: 9781780408798 (eBook)

Prediction and optimal allocation of agricultural non-point source pollution based on chaos theory

In order to promote the accuracy of agricultural pollution source prediction algorithm, an agricultural pollution source prediction algorithm based on chaotic differential evolution algorithm neural network is proposed in the article. Firstly, it initialises the population of differential evolution algorithm with chaos theory, to promote the diversity for initial population solution; then it improves the differential evolution algorithm by using mean entropy and perturbation variation method to promote its optimise performance. Secondly, it optimises the neural network parameter learning process by using the improved differential evolution algorithm to promote the accuracy of parameters optimisation. Lastly, it applies the proposed algorithm into the example of local agricultural pollution source prediction and the results showed that the proposed method could effectively increase the accuracy of agricultural pollution source prediction.

Use of Nitrogenous Fertilizers and its Impact on Water Quality with Special Reference to Agricultural Development

Water is an essential commodity of life on the earth. It plays a very important role in agricultural development. Agricultural activity impacts the water quality through the movement of chemical fertilizers and other poisonous materials from the agricultural fields to deep aquifers through surface runoff and deep percolation. The important source and cause of agricultural pollution are irrigational return flows and use of nitrogenous fertilizers in which nitrate is the basic component. High concentrations of Nitrate in natural water may cause methemoglobinemia, and have been cited as a risk factor in developing gastric and intestinal cancer. One of the most important negative effect of intensive use of nitrogenous fertilizer use is water eutrophication. Nitrates in the irrigational water serves as a nutrient to plants and crops. The agricultural water quality guide lines proposed by Ayers and Westcot (1994) mentions that the nitrate concentration ranges from 22.5 to 135 mg/l causes slight to moderate restriction and above 135 mg/l nitrate concentration causes severe restriction on crops for irrigational use. Due to the impact of fertilizers on human and environment, it is quite necessary to reduce the nitrate concentrations in natural waters to protected levels.

Change of Soil Nitrogen Leaching with Summer Maize Growing Periods Under Plastic Film Mulched Cultivation in Danjiangkou Reservoir Area, China

As an important form of agricultural non-point source pollution, soil nitrogen leaching deteriorates water quality. Compared with non-mulching cultivated land, field experiment explored the change characteristics of soil nitrogen leaching under plastic film mulching ridge-furrow in Wulongchi small watershed during summer maize growing period. The results showed that the amounts of mulching tillage soil TN and NO3--N leaching were significantly lower than those with non-mulched treatment, by 25.68% and 20.25%, respectively. With the advance of the summer maize growth period, leaching amount of mulched soil TN was highest at seedling stage, lowest at heading stage and higher in maturation period; leaching amount of mulched soil NO3--N was highest at seedling stage, lowest in maturation period; leaching amount of mulched soil NH4+-N was lower at seedling stage, increased to the peak at the jointing stage, decreased to the valley value at heading stage, and obviously increased in maturation period. Linear function relationship was found between mulched soil TN leaching and TN content, while exponential relationship was found between mulched soil NO3--N leaching and NO3--N content. In addition, there was linear function relationship of mulched soil TN and NO3--N leaching amount with soil moisture and rainfall. It was concluded that the plastic film mulched on summer maize could reduce the leaching loss of soil nitrogen, and it would have a significant effect on the reduction of reservoir area of agricultural non-point source pollution.

Organic contaminants in western pond turtles in remote habitat in California

Remote aquatic ecosystems are exposed to an assortment of semivolatile organic compounds (SOCs) originating from current and historic uses, of local and global origin. Here, a representative suite of 57 current- and historic-use pesticides, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons were surveyed in the plasma of the western pond turtle (Emys marmorata) and their potential prey items and habitat. California study sites included Sequoia National Park, Whiskeytown National Recreation Area, and Six Rivers National Forest. Each was downstream of undeveloped watersheds and varied in distance from agricultural and urban pollution sources. SOCs were detected frequently in all sites with more found in turtle plasma and aquatic macroinvertebrates in the two sites closest to agricultural and urban sources. Summed PCBs were highest in Whiskeytown National Recreation Area turtle plasma (mean; 1.56 ng/g ww) compared to plasma from Sequoia National Park (0.16 ng/g ww; p = 0.002) and Six Rivers National Forest (0.07 ng/g ww; p = 0.001). While no current-use pesticides were detected in turtle plasma at any site, both current- and historic-use pesticides were found prominently in sediment and macroinvertebrates at the Sequoia National Park site, which is immediately downwind of Central Valley agriculture. SOC classes associated with urban and industrial pollution were found more often and at higher concentrations at Whiskeytown National Recreation Area. These findings demonstrate a range of SOC exposure in a turtle species with current and proposed conservation status and shed additional light on the fate of environmental contaminants in remote watersheds.

Optimization of typical diffuse herbicide pollution control by soil amendment configurations under four levels of rainfall intensities

Herbicides are a main source of agricultural diffuse pollution due to their wide application in tillage practices. The aim of this study is to optimize the control efficiency of the herbicide atrazine with the aid of modified soil amendments. The soil amendments were composed of a combination of biochar and gravel. The biochar was created from corn straw with a catalytic pyrolysis of ammonium dihydrogen phosphate. The leaching experiments under four rainfall conditions were measured for the following designs: raw soil, soil amended with gravel, biochar individually and together with gravel. The control efficiency of each design was also identified. With the designed equipment, the atrazine content in the contaminant load layer, gravel substrate layer, biochar amendment layer and soil layer was measured under four types of rainfall intensities (1.25 mm/h, 2.50 mm/h, 5.00 mm/h and 10.00 mm/h). Furthermore, the vertical distribution of atrazine in the soil sections was also monitored. The results showed that the herbicide leaching load increased under the highest rainfall intensity in all designs. The soil with the combination of gravel and biochar provided the highest control efficiency of 87.85% on atrazine when the additional proportion of biochar was 3.0%. The performance assessment under the four kinds of rainfall intensity conditions provided the guideline for the soil amendment configuration. The combination of gravel and biochar is recommended as an efficient method for controlling diffuse herbicide pollution.

Policy tools for agricultural nonpoint source water pollution control in the U.S. and E.U.

Purpose – In the USA and Europe, agricultural nonpoint source (NPS) pollution continues to be among the chief impediments to achieving water quality standards. While the implementation of technology-based water pollution control tools has resulted in evident point source pollution abatement, NPSs continue to threaten surface water and groundwater. The purpose of this paper is to draw from environmental policy literature to identify regulatory tools and management approaches that specifically target agricultural NPS pollution and the factors that drive or impede their implementation and enforcement. This paper utilizes the policy tool framework to help characterize the widespread policy problem, distinguishing its unique set of hurdles from other environmental problems. Design/methodology/approach – Discussion of agricultural NPS pollution management approaches is based on a thorough review of relevant environmental policy and environmental economic literature as well as case studies from the USA and Europe. Analysis is based on the policy tool framework. Findings – This study finds that controlling numerous diffuse sources of agricultural pollution requires an integrated approach that utilizes river basin management and a mix of policy instruments. Additionally, findings suggest that transitioning from voluntary mechanisms to more effective instruments based on measurable water quality performance relies predominantly on three factors: first, more robust quality monitoring data and models; second, local participation; and third, political will. Originality/value – This research provides important information for regional and national policymakers in areas where there is increasing pollution and regulatory mandates. Identifying conditions of effective water quality policy is applicable and will be of direct use to agencies charged with pollution control.

Vegetative Filter Strips—A Best Management Practice for Controlling Nonpoint Source Pollution

Increasing numbers of pollutants have been observed in natural water systems. As awareness of agricultural sources of water pollution has grown, Best Management Practices (BMPs) have been specifically designed to address agricultural water pollutants and protect water quality. This 4-page fact sheet introduces one of the BMPs, Vegetative Filter Strips (VFSs), which efficiently control nonpoint pollution such as sediments, nutrients, and pesticides. The publication covers primary functions, key design factors, and maintenance of VFSs. Written by Lei Wu, Rafael Muñoz-Carpena, and Yuncong Li, and published by the UF Department of Soil and Water Science, October 2015. SL432/SS646: Vegetative Filter Strips—A Best Management Practice for Controlling Nonpoint Source Pollution (ufl.edu)

Environmental forensics in groundwater coupling passive sampling and high resolution mass spectrometry for screening

One of the difficulties encountered when monitoring groundwater quality is low and fluctuating concentration levels and complex mixtures of micropollutants, including emerging substances or transformation products. Combining passive sampling techniques with analysis by high resolution mass spectrometry (HRMS) should improve environmental metrology. Passive samplers accumulate compounds during exposure, which improves the detection of organic compounds and integrates pollution fluctuations. The Polar Organic Chemical Integrative Sampler (POCIS) were used in this study to sequester polar to semi-polar compounds. The methodology described here improves our knowledge of environmental pollution by highlighting and identifying pertinent compounds to be monitored in groundwater.The advantage of combining these two approaches is demonstrated on two different sites impacted by agricultural and/or urban pollution sources where groundwater was sampled for several months. Grab and passive sampling were done and analyzed by liquid chromatography coupled to a hybrid quadrupole time-of-flight mass spectrometer (LC–QTOF). Various data processing approaches were used (target, suspect and non-target screening). Target screening was based on research from compounds listed in a homemade database and suspect screening used a database compiled using literature data. The non-target screening was done using statistical tools such as principal components analysis (PCA) with direct connections between original chromatograms and ion intensity. Trend plots were used to highlight relevant compounds for their identification.The advantage of using POCIS to improve screening of polar organic compounds was demonstrated. Compounds undetected in water samples were detected with these tools. The subsequent data processing identified sentinel molecules, molecular clusters as compounds never revealed in these sampling sites, and molecular fingerprints. Samples were compared and multidimensional visualization of chemical patterns such as molecular fingerprints and recurrent or specific markers of each site were given.