Water Quality Monitoring Studies Research Articles

A preliminary study of direct observation and selected water quality monitoring in Putrajaya Lake: the status between October-December 2022

The objective of this study was to provide the status of water quality based on a direct observation and selected water quality parameters (nitrite, ammonia, and pH) monitoring study between October-December 2022. Between October and November 2022, the levels of the above three surface water quality parameters were measured in 6 different sites throughout Putrajaya Lake. Observational pictures of the sites were also taken, and water samples were collected. In addition to the above observation and water quality monitoring study, the rainfall data was collected from 17th October 2022 to 11th December 2022, cited from the official website of Public Infobanjir (https://publicinfobanjir.water.gov.my/?lang=en) at stations Sg. Anak Gajah and Sg. Limau Manis, was also used to understand the possible correlation. However, further studies are needed. It was found that the water quality status was in good condition, making Putrajaya Lake a safe and suitable lake for aquatic life and recreational activities between October -December 2022. This could be due to the sustainable practices and rainwater harvesting system already implemented at Putrajaya Lake. Putrajaya Lake's water quality monitoring and sustainability practices were well implemented. However, regular maintenance to provide acute monitoring of water quality data at Putrajaya Lakes is necessary in the future.

Biological-based techniques for real-time water-quality studies: Assessment of non-invasive (swimming consistency and respiration) and toxicity (antioxidants) biomarkers of zebrafish

Swimming consistency and respiration of fish are recognized as the non-invasive stress biomarkers. Their alterations could directly indicate the presence of pollutants in the water ecosystem. Since these biomarkers are a routine process for fish, it is difficult to monitor their activity manually. For this reason, experts employ engineering technologies to create sensors that can monitor the regular activities of fish. Knowing the importance of these non-invasive stress biomarkers, we developed online biological behavior monitoring system-OBBMS and online biological respiratory response monitoring system-OBRRMS to monitor real-time swimming consistency and respiratory response of fish, respectively. We continuously monitored the swimming consistency and respiration (OCR, CER and RQ) of zebrafish (control and atrazine-treatments) for 7 days using our homemade real-time biological response monitoring systems. Furthermore, we analyzed oxidative stress indicators (SOD, CAT and POD) within the vital tissues (gills, brain and muscle) of zebrafish during stipulated sampling periods. The differences in the swimming consistency and respiratory rate of zebrafish between the control and atrazine treatments could be precisely differentiated on the real-time datasets of OBBMS and OBRRMS. The zebrafish exposed to atrazine toxin showed a concentration-dependent effect (hypoactivity). The OCR and CER were increased in the atrazine treated zebrafish. Both Treatment I and II received a negative response for RQ. Atrazine toxicity let to a rise in the levels of SOD, CAT and POD in the vital tissues of zebrafish. The continuous acquisition of fish signals is achieved which is one of the main merits of our OBBMS and OBRRMS. Additionally, no special data processing was done, the real-time data sets were directly used on statistical tools and the differences between the factors (groups, photoperiods, exposure periods and their interactions) were identified precisely. Hence, our OBBMS and OBRRMS could be a promising tool for biological response-based real-time water quality monitoring studies.

Assessing Water Quality Dynamics in Tidally Influenced Blackwater Rivers along a Rural–Urban Gradient

The aim of this research was to identify the impacts of land use and subsequent pulse-driven events on water quality across a gradient of urbanization spanning three blackwater rivers in northeast Florida that contribute to a common estuary ecosystem. Three blackwater rivers in St. Augustine, FL, were classified as rural, suburban, and urban, based on percentages of residential, industrial, and commercial parcel type. Turbidity, dissolved oxygen, fluorescent dissolved organic matter, chlorophyll a, salinity, and pH were measured at 15 min intervals from May to December 2020. Monthly phosphate, nitrate, ammonium, total coliforms, and E. coli concentrations were also examined. Principal component analyses identified the distance to the freshwater source, distance to the inlet, salinity, dissolved oxygen, and pH as major sources of variance between the sites. Significant physicochemical differences between sites are more likely due to a site’s proximity to an inlet or freshwater source, rather than the percent of urban parcels, and site distance to freshwater and saltwater influences should be considered due to its influence on water quality in estuarine systems. This study provides insight into potential water quality responses to urbanization, or lack thereof, and addresses challenges in selecting the optimal site locations for long-term in situ water quality monitoring studies of urbanization in blackwater rivers.

High-frequency fecal indicator bacteria (FIB) observations to assess water quality drivers at an enclosed beach.

Fecal indicator bacteria (FIB) are monitored at beaches to assess water quality and associated health risk from recreational exposure. However, monitoring is generally conducted infrequently (i.e. weekly or less often), potentially leading to inaccurate assessment of water quality at a beach at the time of use. While some work has shown that FIB in marine environments can vary over short (e.g. subhourly) time scales, that work has been mainly focused on 'open' beaches. 'Enclosed' beaches-those that are partially barriered from exchange with offshore water and thus have different residence times and mixing dynamics in the nearshore environment-have been less studied. Here we present results from a high-frequency (once per 30 minutes) FIB sampling event conducted within a Central California, USA, harbor over 48 hours. FIB concentrations at this enclosed site were more variable at high-frequencies than what has been reported at open beach sites. Correlation and regression analyses showed FIB concentrations were most strongly associated with chlorophyll a concentration, turbidity, wind speed, and tide level. Results indicate the importance of measuring FIB concentrations and explanatory environmental parameters at appropriate temporal resolutions when conducting water quality monitoring or source tracking studies. Overall, this work highlights how high-frequency sampling can effectively provide information about water quality dynamics at beaches of interest.

Public Effective Dose Assessment Using Gross Alpha and Beta Radioactivity Levels of Tap Drinking Water in the District of Abidjan, Cote d’Ivoire

In order to assess public effective dose due to gross alpha and beta in water, 43 tap water samples were collected from different areas in the District of Abidjan. Using the low background Gas-less Automatic Alpha/Beta counting system (Canberra iMaticTM) for analysis, the gross alpha and beta concentrations found varied from 0.001 ± 0.002 to 0.063 ± 0.050 Bq/l with an average of 0.013 ± 0.012 Bq/l and from 0.067 ± 0.080 to 0.320 ± 0.120 Bq/l with an average of 0.174 ± 0.076 Bq/l, respectively in samples. The public effective dose assessment showed values of dose to ingestion of alpha and beta emitter radionuclides lower than the recommended value of dose for drinking water 0.1 mSv/y, except in 30% of the samples. These results show the need for additional studies to be conducted in order to clarify the hazardousness of these water samples. However, this study still remains important because it has provided necessary data for future tap water quality monitoring studies in the District of Abidjan.

Museum records of California Trichoptera: potentially useful information to provide larval-adult associations for improving water quality surveys

Examination of museum records indicate that 358 species of Trichoptera belonging to 83 genera and 20 families have been collected in California. The families Limnephilidae and Rhyacophilidae exhibited the greatest richness. Museums holding species records from California are listed, which enables localities to be obtained digitally or through museum contacts. Far more digital records for Trichoptera are available from statewide, water-quality monitoring programs than from museums, but identifications are typically made at the generic level where metrics describing pollution tolerance are less valuable than when at the species level. Increased numbers of larval-adult associations may result when researchers can use these museum records to involve volunteer community scientists in making targeted collections to provide specimens for rearing, metamorphotypes, or molecular analysis. This approach could enhance both water quality monitoring and community ecology studies of Trichoptera and other aquatic insects.

Efectos de las actividades antrópicas sobre parámetros metabólicos en un bivalvo invasor y otro nativo en el tramo inferior del río Paraná

The relationship between anthropogenic pollution, geochemistry and natural dynamics of freshwater ecosystems determine the spatial and temporal patterns of water quality. Human activities and the introduction of exotic species are the main causes of the decrease in biological diversity. The introduction and spread of the invasive bivalve Corbicula fluminea endangers the presence of the native bivalve Diplodon delodontus. Through oxidative stress indicators, it is possible to quantify the response of organisms to changes in physical-chemical, natural and/or anthropogenic variables. Therefore, the objective was to interpret the effect of changes in physical-chemical variables, contaminants and/or xenobiotics on the metabolic responses of C. fluminea and D. delodontus on the Paraná de las Palmas river. Randomly, we established a sampling point to collect individuals (60 of invasive and 10 of native bivalve) for the assembly of 10 cages by species and placement site in September 2018. In June and September 2019, five cages of each species were extracted at random. In water, physical-chemical parameters and metals were measured, and in the organs of both species, protein concentration, glycogen, lipid damage, reduced glutathione content, enzymatic activity of catalase and glutathione-S-transferase. In general, the physical-chemical and metal parameters increased significantly from June to September. Metals exceeded freshwater quality guideline levels for the protection of aquatic life. In relation to the changes in these variables, the metabolic parameters differed between organs and species from June to September. The gills and digestive gland of C. fluminea showed higher metabolic responses and faster than D. delodontus. The study of invasive and native species through the measurement of multiple variables is a useful tool to characterize the environment, with application prospects in water quality monitoring and conservation studies.

Distributional Trends and Species Richness of Maryland, USA, Stoneflies (Insecta: Plecoptera), with an Emphasis on the Appalachian Region

Faunistic studies of regional biodiversity of aquatic insects are increasing in importance as declines are noted globally. Federal and state government conservation attempts for rare and threatened species are predicated upon the initial research of specialized taxonomists and trained field biologists. The reporting of aquatic insect occurrence data provides a baseline for conservation agencies to compare water quality monitoring studies. Updated field work, literature reviews, and database queries for stoneflies from the mid-Atlantic United States of America state of Maryland necessitated an assessment of species diversity for the state. Seven new state records and one new literature record are presented, bringing the total number of species to 122. Chao1 estimates of species richness are presented for diversity hotspots and the state as a whole, indicating that increased sampling is still necessary to fully understand diversity patterns. Accompanying are assessments of elevation trends and adult presence patterns within nine families. Collections are predominantly restricted to the Appalachian region. Herein, we direct future efforts to focus on understudied regions. An outline of distribution knowledge for species is presented to inform upcoming State Wildlife Action Plans.

Real-time determination of water status upon simultaneous zebrafish exposure to sublethal concentrations of CuSO4

Water pollution from commonly occurring contaminants (metals, xenobiotics, etc.) is a serious global problem. Copper is a commonly occurring water contaminant. A variety of physiological and biological methods have been developed to monitor water quality. The assessment of biological responses is an effective method for identifying the harmful effects of contaminants on ecosystems. Fish is a highly recommended animal model in water quality monitoring. Swimming consistency (firmness) and respiratory metabolism (oxygen consumption rate, carbon dioxide excretion rate and respiratory quotient) are essential for fish to maintain body homeostasis toward coping with environmental stress. We exposed zebrafish to different concentrations (Treatment I-0.1 mg/L and Treatment II-1.58 mg/L) of CuSO4. We have continuously quantified the strength of behavior (swimming consistency) and physiological (respiratory rates) biomarkers for ten days using an online monitoring system of swimming behavior and external respiration. Swimming consistency and respiratory rates of zebrafish (p<0.05) decreased in the CuSO4-treated groups compared to the control group. Avoidance behavior has led to an endpoint behavior at copperiedus. The time-delayed toxic effect has resulted in CuSO4 treatment groups. We checked for swimming consistency aberration on the artificial neural array, Self-organizing map (SOM). Circadian rhythms were influenced by prolonged exposure to CuSO4 toxicity. A concentration- and duration-dependent behavior anomaly was noted in this study. Swimming behavior and respiratory metabolism patterns are sensitive non-invasive stress biomarkers for water quality monitoring studies.

A preliminary evaluation of microbial water quality in the irrigation pond.

This study aimed to determine the microbial water quality of Imrahor Pond by enumerating the coliform bacteria levels in the area. Water samples were collected biweekly from the surface and bottom waters at seven points in the pond. Samples were analyzed for total coliforms, Escherichia coli, physicochemical parameters (water temperature, conductivity, pH, turbidity, dissolved oxygen, nitrate) and 1-day rainfall. The average values of TC and E.coli were 1487.4 and 36.3 MPN/100 ml, respectively. TC concentrations/physicochemical parameters were met at least 2nd class water quality class and E.coli results were met "guideline value" (E.coli < 250 MPN/100ml) of national regulation. Overall, among measured physicochemical parameters, rainfall had the strongest positive correlation (r = 0.377 for total coliforms and r = 0.466 for E.coli, p< 0.05) with both indicators, indicted that surface runoff due to rainfall is the main factor which effects microbial water quality in the study area. This study demonstrated the preliminary microbial water quality results (TC and E.coli) in the Imrahor Pond and can serve as a basis for developing more precise water quality monitoring and management studies in the future. PRACTITIONER POINTS: Prevalence of TC and E.coli in the surface and bottom waters of Imrahor Pond were investigated for the first time. Imrahor Pond was met guideline value of national regulations based on E.coli concentrations, in the study period. Surface runoff after rainfall was the main environmental factor which influenced the microbial water quality of the pond.

Initial findings from agricultural water quality monitoring at the edge-of-field in Arkansas

With farm-scale knowledge of how production practices affect water quality, land managers and agricultural producers can make more informed decisions on implementing soil and water conservation practices that sustain productivity and protect water resources. The Lower Mississippi River Basin is a major agricultural production region for rice (<i>Oryza sativa</i> L.), cotton (<i>Gossypium hirsutum</i> L.), and soybean (<i>Glycine max</i> [L.] Merr.); however, there is limited knowledge on how agronomic practices in those southern cropping systems affect water quality. Results from environmental models indicate commercial fertilizer from agricultural fields contributes substantially to the hypoxic zone in the northern Gulf of Mexico. To expand understanding of runoff water quality at the field scale, edge-of-field water quality monitoring studies were carried out in nine commercial rice, cotton, and soybean fields in northeastern Arkansas over multiple seasons. These year-round monitoring activities generated 23 site-years of data on sediment and nutrient concentrations and loads with various soils and crop rotation regimes. Discharge from runoff, nitrite-nitrogen (NO₂-N), nitrate-nitrogen (NO₃-N), total N, soluble phosphorus (P), total phosphorus (TP), and suspended sediment concentration on a per-event basis were measured. The results indicate that the nongrowing season loads and concentrations of several measured components were statistically higher than those measured during the growing season, lending support to the need for off-season practices such as winter cover crops and winter shallow water storage. Lower concentrations and loads of nutrients and sediment were observed in rice fields compared to cotton and soybean systems. These differences are likely due to soil type but are also related to the water management system of flooded rice fields compared to furrow irrigated row crops. These findings provide baseline runoff water quality data and will help inform regional budgets of nutrients and sediment loss. Such information can assist land managers and conservationists in directing resources more effectively. These data also will support modelers in their efforts to calibrate, verify, validate, and estimate uncertainty for simulations of nutrients and sediment loss.

Temporal and spatial variability of instream indicator bacteria (Escherichia coli) and implications for water quality monitoring.

Many water quality monitoring programs quantify Escherichia coli, an indicator of fecal contamination and potential sewage pollution. However, interpretation of E. coli data can be complex due to abiotic factors that influence its growth and mortality. The goal of this study was to quantify the variability of E. coli in a river and assess the impact of that variability on water quality monitoring study design and sewage pollution source identification. Over 1900 samples were collected and analyzed from 2007 to 2017 in the Norwalk River in Connecticut. Sixty-six percent of the samples collected during weekly to monthly monitoring had E. coli concentrations below 200 CFU/100 mL, indicating that elevated bacteria concentrations were captured infrequently. Patterns observed during daily sampling indicated that the randomization of sampling days within a week may support the identification of pollution sources driven by human behavioral patterns. Spatial autocorrelation in bacteria concentrations was not observed between sites, indicating that the sample locations were not spaced sufficiently close together to be redundant for monitoring. On finer spatial scales however, detection of a known pollution source was found to be challenging at even short distances downstream, with less than 25% of the original source concentration detected at 10 m downstream and less than 10% by 1000 m downstream, suggesting that a high density of study sites may be needed to detect potential sources. These findings can be used to better understand the natural variability of this important indicator organism in freshwater systems, and inform more efficient and effective monitoring.

DANUBE DELTA: MONITORING AND ECOLOGICAL STATUS. A LINK BETWEEN THE PAST AND THE FUTURE

The paper aims a review of the water quality monitoring and evaluation studies conducted at National R&amp;D Institute for Industrial Ecology over the last ten years, at the level of aquatic ecosystem complexes in the Danube Delta. The paper will include a broad compendium of data including: a data bank of abiotic variables which control the structure and composition of biotic communities; studies of ecological status assessment; methodology development for assessing the bioaccumulation of chemical pollutants (metals) in the biota; ecotoxicological study of surface water and sediment on aquatic organisms (algae, crustaceans, rotifers); studies on the benthic invertebrate species as biological vectors for pathogens; technical / scientific support for 5 national / international project proposals; 19 papers published in international / national journals; 22 papers presented at international / national scientific conferences.

Generalized Concentration Addition Model Predicts Glucocorticoid Activity Bioassay Responses to Environmentally Detected Receptor-Ligand Mixtures.

Many glucocorticoid receptor (GR) agonists have been detected in waste and surface waters domestically and around the world, but the way a mixture of these environmental compounds may elicit a total glucocorticoid activity response in water samples remains unknown. Therefore, we characterized 19 GR ligands using a CV1 cell line transcriptional activation assay applicable to water quality monitoring. Cells were treated with individual GR ligands, a fixed ratio mixture of full or partial agonists, or a nonequipotent mixture with full and partial agonists. Efficacy varied (48.09%-102.5%) and potency ranged over several orders of magnitude (1.278 × 10-10 to 3.93 × 10-8 M). Concentration addition (CA) and response addition (RA) mixtures models accurately predicted equipotent mixture responses of full agonists (r2 = 0.992 and 0.987, respectively). However, CA and RA models assume mixture compounds produce full agonist-like responses, and therefore they overestimated observed maximal efficacies for mixtures containing partial agonists. The generalized concentration addition (GCA) model mathematically permits < 100% maximal responses, and fell within the 95% confidence interval bands of mixture responses containing partial agonists. The GCA, but not CA and RA, model predictions of nonequipotent mixtures containing both full and partial agonists fell within the same statistical distribution as the observed values, reinforcing the practicality of the GCA model as the best overall model for predicting GR activation. Elucidating the mechanistic basis of GR activation by mixtures of previously detected environmental GR ligands will benefit the interpretation of environmental sample contents in future water quality monitoring studies.

Emerging Design and Characterization Guidelines for Polymer-Based Infrared Photodetectors.

Infrared photodetectors are essential to many applications, including surveillance, communications, process monitoring, and biological imaging. The short-wave infrared (SWIR) spectral region (λ = 1-3 μm) is particularly powerful for health monitoring and medical diagnostics because biological tissues show low absorbance and minimal SWIR autofluorescence, enabling greater penetration depth and improved resolution in comparison with visible light. However, current SWIR photodetection technologies are largely based on epitaxially grown inorganic semiconductors, which are costly, require complex processing, and impose cooling requirements incompatible with wearable electronics. Solution-processable semiconductors are being developed for infrared detectors to enable low-cost direct deposition and facilitate monolithic integration and resolution not achievable using current technologies. In particular, organic semiconductors offer numerous advantages, including large-area and conformal coverage, temperature insensitivity, and biocompatibility, for enabling ubiquitous SWIR optoelectronics. This Account introduces recent efforts to advance the spectral response of organic photodetectors into the SWIR. High-performance visible to near-infrared (NIR) organic photodetectors have been demonstrated by leveraging the wealth of knowledge from organic solar cell research in the past decade. On the other hand, organic semiconductors that absorb in the SWIR are just emerging, and only a few organic materials have been reported that exhibit photocurrent past 1 μm. In this Account, we survey novel SWIR molecules and polymers and discuss the main bottlenecks associated with charge recombination and trapping, which are more challenging to address in narrow-band-gap photodetectors in comparison with devices operating in the visible to NIR. As we call attention to discrepancies in the literature regarding performance metrics, we share our perspective on potential pitfalls that may lead to overestimated values, with particular attention to the detectivity (signal-to-noise ratio) and temporal characteristics, in order to ensure a fair comparison of device performance. As progress is made toward overcoming challenges associated with losses due to recombination and increasing noise at progressively narrower band gaps, the performance of organic SWIR photodetectors is steadily rising, with detectivity exceeding 1011 Jones, comparable to that of commercial germanium photodiodes. Organic SWIR photodetectors can be incorporated into wearable physiological monitors and SWIR spectroscopic imagers that enable compositional analysis. A wide range of potential applications include food and water quality monitoring, medical and biological studies, industrial process inspection, and environmental surveillance. There are exciting opportunities for low-cost organic SWIR technologies to be as widely deployable and affordable as today's ubiquitous cell phone cameras operating in the visible, which will serve as an empowering tool for users to discover information in the SWIR and inspire new use cases and applications.

Large-Scale Permanent Slide Imaging and Image Analysis for Diatom Morphometrics

Light microscopy analysis of diatom frustules is widely used in basic and applied research, notably taxonomy, morphometrics, water quality monitoring and paleo-environmental studies. Although there is a need for automation in these applications, various developments in image processing and analysis methodology supporting these tasks have not become widespread in diatom-based analyses. We have addressed this issue by combining our automated diatom image analysis software SHERPA with a commercial slide-scanning microscope. The resulting workflow enables mass-analyses of a broad range of morphometric features from individual frustules mounted on permanent slides. Extensive automation and internal quality control of the results helps to minimize user intervention, but care was taken to allow the user to stay in control of the most critical steps (exact segmentation of valve outlines and selection of objects of interest) using interactive functions for reviewing and revising results. In this contribution, we describe our workflow and give an overview of factors critical for success, ranging from preparation and mounting through slide scanning and autofocus finding to final morphometric data extraction. To demonstrate the usability of our methods we finally provide an example application by analysing Fragilariopsis kerguelensis valves originating from a sediment core, which substantially extends the size range reported in the literature.

Effect of Geogenic Factors on Water Quality and Its Relation to Human Health around Mount Ida, Turkey

Water–rock interactions strongly influence water quality. Waters originating from highly altered zones affect human health. Mount Ida region in western Anatolia is an example for such geogenic interactions and additional anthropogenic impacts. A water quality monitoring study was held and a total of 189 samples were collected from 63 monitoring stations to characterize the quality of water resources and its relation with human health. The results indicated that waters originating from altered volcanic rocks that are mainly used for drinking purposes have low pH, high conductivity and elevated trace element levels. In addition, a number of acidic mining lakes were formed in the open pits of abandoned mine sites in the study area and pyrite oxidation in altered volcanic rocks resulted in extremely acidic, high mineral content and toxic waters that demonstrate an eminent threat for the environmental health in the area. Overall, the water quality constituents in Mount Ida region had a spatially variable pattern and were locally found to exceed the national and international standards, mainly due to geogenic alteration zones and anthropogenic intervention.

Use of quantitative microbial risk assessment to improve interpretation of a recreational water epidemiological study

We conducted a supplemental water quality monitoring study and quantitative microbial risk assessment (QMRA) to complement the United States environmental protection agency's (U.S. EPA) National Epidemiological and Environmental Assessment of Recreational water study at Boquerón beach in Puerto Rico to estimate the gastrointestinal (GI) illness levels associated with recreational water exposures. The previously reported epidemiological study had sufficient statistical power to detect an average illness rate of approximately 17 swimming associated GI illnesses per 1000 recreation events or greater, and found no consistent relationships between water quality measured by fecal indicator organisms (FIO) and swimming-associated illnesses (U.S. EPA, 2010a). The QMRA incorporated monitoring data for pathogens and fecal indicators collected during the epidemiological study period and calculated average swimming-associated illness levels that were approximately two GI illnesses per 1000 recreation events. To our knowledge, this is the first time that a comprehensive water quality monitoring program and QMRA analysis has been conducted in parallel with a recreational water epidemiological study. The QMRA results were consistent with the low rate of reported illnesses during the 2009 epidemiological study (i.e. <17 GI illnesses per 1000 recreation events) and provide additional context for understanding the epidemiological results. The results illustrate that coupling QMRA with an epidemiological study at a single study site provides a unique ability to understand human health illnesses especially under conditions where water quality, as measured by traditional FIO is good and/or average illness rates are lower than can be quantified via epidemiological methods alone.

SHERPA: an image segmentation and outline feature extraction tool for diatoms and other objects.

BackgroundLight microscopic analysis of diatom frustules is widely used both in basic and applied research, notably taxonomy, morphometrics, water quality monitoring and paleo-environmental studies. In these applications, usually large numbers of frustules need to be identified and/or measured. Although there is a need for automation in these applications, and image processing and analysis methods supporting these tasks have previously been developed, they did not become widespread in diatom analysis. While methodological reports for a wide variety of methods for image segmentation, diatom identification and feature extraction are available, no single implementation combining a subset of these into a readily applicable workflow accessible to diatomists exists.ResultsThe newly developed tool SHERPA offers a versatile image processing workflow focused on the identification and measurement of object outlines, handling all steps from image segmentation over object identification to feature extraction, and providing interactive functions for reviewing and revising results. Special attention was given to ease of use, applicability to a broad range of data and problems, and supporting high throughput analyses with minimal manual intervention.ConclusionsTested with several diatom datasets from different sources and of various compositions, SHERPA proved its ability to successfully analyze large amounts of diatom micrographs depicting a broad range of species. SHERPA is unique in combining the following features: application of multiple segmentation methods and selection of the one giving the best result for each individual object; identification of shapes of interest based on outline matching against a template library; quality scoring and ranking of resulting outlines supporting quick quality checking; extraction of a wide range of outline shape descriptors widely used in diatom studies and elsewhere; minimizing the need for, but enabling manual quality control and corrections. Although primarily developed for analyzing images of diatom valves originating from automated microscopy, SHERPA can also be useful for other object detection, segmentation and outline-based identification problems.

Fluoride in ground water: a comment on “fluorine contamination in ground water: a major challenge” published in Environmental Monitoring and Assessment, (2011) 173, 955–968

The objective of this paper is to highlight the erroneous map used in depicting the sampling locations, reported high fluoride values, and other minor mistakes published by Dar et al. (2011) for the benefit of the scientific community. It is estimated that about 80% of the diseases in the world are attributed to poor quality of drinking water, and fluoride contamination in drinking water is responsible for 65 % of endemic fluorosis in the world (WHO 1984). Fluorosis is a non curable disease so far, and its severity depends on the fluoride concentration and the intake. In India, more than 90 % of the villages use groundwater for drinking and 50 % of these sources are contaminated with fluoride. In fact, a prevalence of dental fluorosis is responsible to affect more than 40 million people in India (Karthikeyan et al. 2005). Therefore, fluoride concentration in groundwater needs to be monitored to assess its suitability for consumption. Occurrence of high fluoride content in groundwater can be associated with diverse geological environments; ranging from sedimentary rocks (Battaleb-Looie et al. 2012) to crystalline rocks (Jacks et al. 2005; D’Alessandro et al. 2008) and to volcanic aquifers (Gaciri and Davies 1993; Ashley and Burley 1995; Tekle-Haimanot et al. 2006; Vivona et al. 2007; Rango et al. 2009). Considering the value attached to the fluoride contamination in ground water, any monitoring investigation must be carried out with high scientific standards at each stage such as sampling, analysis, interpretation and data presentation. A paper entitled “Fluorine contamination in ground water: a major challenge” published in Environmental Monitoring and Assessment by Dar et al. (2011) reported the groundwater fluoride concentration for Kancheepuram district of Tamil Nadu, India. In this paper, some of the locations have been implicated to contain relatively high fluoride content. A close scrutiny of the paper revealed error with regard to the sampling location itself. Considering the importance of the investigated site and their fluoride content for the public and government, it is essential to clarify the mistakes. In this paper, we have discussed the drawbacks such as (a) the use of erroneous sampling locationmap resulting inwrong implications on the outcome of the study, (b) non-conformance of hydrochemical data with respect to ionic balance, a prerequisite in water quality analyses and (c) reported high fluoride values for a specific site which has subsequently been studied by us. Spatial presentation of data in water quality monitoring studies has considerable scientific and management implication. Name of the sampling locations (village/town) may be familiar to a limited researcher belonging to the same area; however, for important geographical information to universal readers, providing the correct map of the sampling sites is a scientific need. Thus, any error in identifying sampling points in the map greatly distorts the study results and hence nullifies the very purpose of the study. Errors in the sampling location map used by Environ Monit Assess (2014) 186:2159–2163 DOI 10.1007/s10661-013-3525-4