Monitoring Of Organic Contaminants Research Articles

A modified QuEChERS method for the generic and rapid determination of pesticides and mycotoxins in raw coffee beans by liquid chromatography-quadrupole-time-of-flight mass spectrometry

In this work, a simple, high-throughput, and sensitive analytical method for simultaneously determining 270 pesticides and 13 mycotoxins from different chemical classes in raw coffee beans was developed. The modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) process mainly involved the effects of hydration volume, extraction solvent, extraction salt, and the type and amount of adsorbent used for sample extraction and purification. The samples were detected by liquid chromatography-quadrupole-time-of-flight mass spectrometry (LC-Q-TOF/MS) with a self-built database. The method effectively reduced matrix effects and the 283 compounds showed good linearity in their respective linear ranges (R2> 0.99). The screening detection limits (SDL) of the method were in the range of 0.1–20 μg/kg, and the limits of quantification (LOQ) were in the range of 0.2–20 μg/kg. The average recoveries of the 283 compounds at three spiked levels ranged from 72.1 % to 114.9 %, with intra-day and inter-day relative standard deviations less than 9.8 % and 17.1 %, respectively. The recoveries of all analytes ranged from 70.0 % to 120.0 % at three spiked levels (1×LOQ, 2×LOQ, and 10×LOQ), with relative standard deviations less than 20.0 %. The results were satisfactory according to the SANTE/11312/2021 guidelines. The method successfully analyzed 34 batches of actual samples, with concentrations ranging from 0.1 to 61.9 μg/kg for pesticides and 2.3–43.0 μg/kg for mycotoxins. This method provides a powerful tool for monitoring organic contaminants in raw coffee beans.

Levels and species-specific organochlorine accumulation in three shark species from the western Gulf of California with different life history traits

Organochlorine compounds (OCs), such as organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), remain ubiquitous in marine ecosystems despite their prohibition or restriction, posing a risk to marine wildlife and humans. Their accumulation in liver tissue and potential toxicity in three exploited shark species (the scalloped hammerhead, Sphyrna lewini; the Pacific sharpnose shark, Rhizoprionodon longurio; and the Pacific angel shark, Squatina californica) with different physiological and ecological features from the western Gulf of California (GC) were investigated. Forty of the 47 OCs analyzed were identified, evidencing a greater agricultural than industrial influence considering the high DDTs/PCBs ratios. The DDT group was the main contributor to ∑OCs in the three species, while hexa- and hepta-CBs dominated the PCB profiles. S. lewini (juveniles) and R. longurio (juveniles and adults) had similar and significantly (p < 0.05) higher ∑OCP concentrations than S. californica (juveniles and adults), which is attributed to their migration to other polluted regions of the gulf. The three species' ∑PCB levels (lipid weight) were comparable and considered low in comparison to those documented in prior studies conducted worldwide. No intraspecific differences were observed when comparing by sex, but OC concentrations were higher in larger individuals. S. lewini and R. longurio showed different OC bioaccumulation trends against size, while no relationship between size and ∑OC concentrations was observed in S. californica. All shark species' toxic equivalents (TEQs) were calculated from dioxin-like PCB concentrations and were far below the established TEQ fish thresholds. However, future research is needed regarding the possible PCB and OCP effects in elasmobranchs. This study provides the basis for monitoring organic contaminants in predatory sharks from the western GC. It also highlights the importance of further research on unintentionally produced organochlorine environmental levels and sources.

Passive sampling hydrophilic and hydrophobic bisphenol analogues using hydrophilic-lipophilic balance sorbent-embedded cellulose acetate membrane in surface waters

Bisphenol analogues (BPs) are ubiquitous emerging contaminants in water environments and have wide polarity ranges (1.65 < log Kow < 7.2). Integrated passive sampling strategy rarely contains hydrophilic and hydrophobic organics simultaneously, while the method has good application perspective in monitoring organic contaminants. This work evaluated passive sampling performance for fifteen BPs in a newly developed passive sampler, i.e., hydrophilic-lipophilic balance sorbent-embedded cellulose acetate membrane (HECAM). In the dynamic accumulation experiments, both hydrophilic and hydrophobic BPs (including moderately hydrophilic BPs) well followed first-order kinetic uptake in the HECAMs. The estimated uptake rate constants, elimination rate constants, and equilibrium partition coefficients for BPs ranged from 4.4 L g−1 d−1 to 14.7 L g−1 d−1, 0.22 d−1 to 0.72 d−1, and 3.99 to 4.64, respectively. The kinetic parameters for BPs in HECAM show limited correlations to log Kow values, which the rule differs from traditional passive sampler. In the study of elimination kinetics, three deuterium labeled compounds showed incomplete elimination in HECAM and did not follow first-order isotropic exchange kinetics. Dual sorption mechanisms including both adsorption and partition were found for chemicals in HECAM, which the partitioned part could release to water and the adsorbed part could not easily release to water from HECAM. As a result, performance reference compounds (PRCs) calibration may be inapplicable to HLB sorbent-based passive sampler. The field deployment of HECAM in coastal waters of Guangdong, China resulted in the detection of eleven BPs, which indicated that the waters have been polluted by various BPs. Finally, monitoring strategy of simultaneous passive sampling hydrophobic and hydrophilic organic contaminants in surface waters was recommended.

In-situ quantitative monitoring the organic contaminants uptake onto suspended microplastics in aquatic environments

Microplastics act as a source of organic contaminants in aquatic environments and thus affect their environmental fate and toxicity. Because of the weak and reversible interactions between microplastics and organic species, the organic coronas vary with their surrounding environments. Thus, in order to evaluate the possible environmental risks of microplastics, methods for evaluating the dynamic uptake of organic contaminants onto suspended microplastics in aquatic environments are greatly desired. In this work, a UV–vis spectroscopy-based approach was developed for in-situ monitoring organic contaminants uptake onto suspended microplastics after correcting the light scattering interference from microplastics suspensions and establishing the nonlinear relationship between concentration and light absorbance of organic species. The inverse adding-doubling method based on radiative transfer theory was adopted to correct the light scattering effect of suspensions. Then, the resulting mixed absorption spectra were decomposed to calculate the concentrations of the aqueous and adsorbed organic species simultaneously with a nonlinear calibration method. The uptake processes of bisphenol A and p-nitrophenol onto nylon 66 microparticles were monitored with this approach and confirmed by high-performance liquid chromatography analysis. The approach was validated by applying it to natural water samples, and the equilibrium adsorption capacity was found to be interfered mainly by the protein-like substances. This approach has high accuracy, good reproducibility, remarkable universality, and ease of handling, and also provides a potential tool for characterizing the corona formation process on suspended particles both in natural and artificial environments, such as eco-corona formation and engineering surface modification on nano/micro-particles.

Real-time and hazard-free water quality monitoring based on microwave planar resonator sensor

This manuscript presents the development of a microwave microfluidic sensor for monitoring organic contaminants in water. This method offers a contactless, non-intrusive, and real-time monitoring system. The sensor is comprised of a compact double-ring resonator integrated with a 3D-printed microfluidic channel, operating at 4.5∼4.6 GHz with a quality factor of 120. The channel configuration on the resonator ensures maximum interaction between the electromagnetic field and the liquid sample and provides high sensitivity and resolution. The developed sensor was used to monitor organics (glucose, acetate and glucose-acetate mix) and the chemical oxygen demand (COD) standard (potassium hydrogen phthalate) in concentrations ranging from 50 to 800 mg/L as COD. The feasibility, reproducibility, and accuracy of the sensing platform was further validated by analyzing the S21 characteristic of the sensor. A monotonic decrease in the resonant amplitude of S21 was observed as the concentration of organics increased, with the sensitivity of 0.603 dB/COD [g/L], 0.087 dB/COD [g/L], 0.099 dB/COD [g/L] and 0.077 dB/COD [g/L] for potassium hydrogen phthalate, sodium acetate, glucose, and a glucose- acetate mixture, respectively. The findings support the capability of the microwave microfluidic sensor to detect dielectric properties variation associated with a minimum concentration of 17 mg/L glucose in water in real time. The response of the sensor was compared with conventional COD measurements using potassium dichromate digestion to compare the efficiency of the developed sensor with the spectrophotometric method to measure COD.

Identification of contaminants of concern in the upper Tagus river basin (central Spain). Part 2: Spatio-temporal analysis and ecological risk assessment

This study provides a description of the water quality status in the tributaries of the upper Tagus River and a preliminary risk assessment for freshwater organisms. A wide range of physico-chemical parameters, nutrients, metals and organic contaminants (20 pesticides, and 32 point source chemicals, mainly pharmaceuticals) were monitored during spring, summer and autumn of 2016. Monitoring of organic contaminants was performed using conventional grab sampling and passive samples (POCIS). The variation of the different groups of parameters as regards to land use and sampling season was investigated. The prioritization of organic and inorganic contaminants was based on the toxic unit (TU) approach, using toxicity data for algae, invertebrates and fish. Finally, the compliance with the Environmental Quality Standards (EQS) set as part of the Water Framework Directive (WFD) was evaluated for the listed substances. This study shows that the land use characteristics had a large influence on the spatial distribution of the contaminants and other water quality parameters, while temporal trends were only significant for physico-chemical parameters, and marginally significant for insecticides. Acute toxicity is likely to occur for some metals (copper and zinc) in the most impacted sites (TU values close to or above 1). Low acute toxicity was determined for organic contaminants (individual compounds and mixtures) on the basis of grab samples. However, the assessment performed with POCIS samples identified diuron, chlorpyrifos and imidacloprid as potentially hazardous compounds. Several contaminant mixtures that may cause chronic toxicity and that should be considered in future regional chemical monitoring plans were identified. Our study also shows that some metals and pesticides exceeded the WFD regulatory thresholds and that only 30% of the sampled sites had a good chemical status. Further research is needed to identify chemical emission sources and to design proper abatement options in the Tagus river basin.

Validation of a modified QuEChERS method for the analysis of organochlorine pesticides in fatty biological tissues using two-dimensional gas chromatography

The monitoring of organic contaminants in the environment has gained tremendous traction in recent times, however, little attention has focused on the development of appropriate methods for the analysis of biological tissues from key sentinel species. In this study, a rapid, low-cost method is presented for the analysis of organochlorine pesticides (OCPs) in fatty biological tissues using a modified QuEChERS (Quick, Easy, Cheap, Efficient, Rugged and Safe) approach. The adapted extraction procedure is tested on biological samples of varying fat content, including fish muscle tissue and two previously untested matrices; coral and adipose tissue. Residue analyses were conducted by two-dimensional gas chromatography−time-of-flight mass spectrometry (GCxGC-TOF-MS). The method was fully validated through the evaluation of recoveries, limits of detection, linearity and precision. Mean recoveries (n = 3) for all 18 target compounds ranged between 69 and 102% across all matrices, with relative standard deviations (RSD) <10% in most cases. Limits of detection (LOD) ranged from 0.1 to 2.0 ng g−1. The method was successfully applied to the analysis of real samples collected from iSimangaliso Wetland Park World Heritage Site, South Africa.

Continuous low-level aquatic monitoring (CLAM) samplers for pesticide contaminant screening in urban runoff: Analytical approach and a field test case

Monitoring of surface waters for organic contaminants is costly. Grab water sampling often results in non-detects for organic contaminants due to missing a pulse event or analytical instrumentation limitations with a small sample size. Continuous Low-Level Aquatic Monitoring (CLAM) samplers (C.I.Agent® Solutions) continually extract and concentrate organic contaminants in surface water onto a solid phase extraction disk. Utilizing CLAM samplers, we developed a broad spectrum analytical screen for monitoring organic contaminants in urban runoff. An intermediate polarity solid phase, hydrophobic/lipophilic balance (HLB), was chosen as the sorbent for the CLAM to target a broad range of compounds. Eighteen urban-use pesticides and pesticide degradates were targeted for analysis by LC/MS/MS, with recoveries between 59 and 135% in laboratory studies. In field studies, CLAM samplers were deployed at discrete time points from February 2015 to March 2016. Half of the targeted chemicals were detected with reporting limits up to 90 times lower than routine 1-L grab samples with good precision between field replicates. In a final deployment, CLAM samplers were compared to 1-L water samples. In this side-by-side comparison, imidacloprid, fipronil, and three fipronil degradates were detected by the CLAM sampler but only imidacloprid and fipronil sulfone were detected in the water samples. However, concentrations of fipronil sulfone and imidacloprid were significantly lower with the CLAM and a transient spike of diuron was not detected. Although the CLAM sampler has limitations, it can be a powerful tool for development of more focused and informed monitoring efforts based on pre-identified targets in the field.

Aquatic Global Passive Sampling (AQUA-GAPS) Revisited: First Steps toward a Network of Networks for Monitoring Organic Contaminants in the Aquatic Environment.

Organic contaminants, in particular persistent organic pollutants (POPs), adversely affect water quality and aquatic food webs across the globe. As of now, there is no globally consistent information available on concentrations of dissolved POPs in water bodies. The advance of passive sampling techniques has made it possible to establish a global monitoring program for these compounds in the waters of the world, which we call the Aquatic Global Passive Sampling (AQUA-GAPS) network. A recent expert meeting discussed the background, motivations, and strategic approaches of AQUA-GAPS, and its implementation as a network of networks for monitoring organic contaminants (e.g., POPs and others contaminants of concern). Initially, AQUA-GAPS will demonstrate its operating principle via two proof-of-concept studies focused on the detection of legacy and emerging POPs in freshwater and coastal marine sites using both polyethylene and silicone passive samplers. AQUA-GAPS is set up as a decentralized network, which is open to other participants from around the world to participate in deployments and to initiate new studies. In particular, participants are sought to initiate deployments and studies investigating the presence of legacy and emerging POPs in Africa, Central, and South America.

Monitoring of organic contamination in the ambient air of microelectronic clean room by proton-transfer reaction/time-of-flight/mass spectrometry (PTR–ToF–MS)

The organic contamination has been recently considered as the most important problem for the photolithography world in the semiconductor industry, especially when the photolithographic methods moved from 130nm node to 32nm node. One of the most common organic compounds found in photolithography areas of the clean room is Trimethylsilanol (TMS), which can adsorb on the optical lenses forming a thin molecular layer, hence causing damages. Salt crystal formation is another potential threat for the optical devices. In the clean rooms, this salt is produced by a light-induced reaction between ammonia and an acid. In the context of semiconductor industry, the involved acid is usually the acetic acid produced by hydrolysis from propylene glycol methyl ether acetate (PGMEA), a commonly used organic compound in the photolithography.Here, we present an innovative analytical method using a state-of-the-art proton-transfer reaction–time-of-flight–mass spectrometer (PTR–ToF–MS) for on-line and continuous survey of volatile organic compounds (VOCs) with an emphasis on TMS and PGMEA. The effect of relative humidity on the detection and fragmentation of these organic compounds was assessed. The new analytical method is operated in a real life clean room environment and the results were compared with those obtained with off-line measurements using automated thermal desorber–gas chromatography–mass spectrometry (ATD–GC–MS) as reference method.The contamination sources were detected and identified, which is of paramount importance for the microelectronic fabrication plant. The trapping efficiency of the chemical filters used for AMCs filtration in the photolithography zone was determined.

Implementing a protocol for selection and prioritisation of organic contaminants in the drinking water value chain: Case study of Rand Water, South Africa

Approaches that prioritise chemicals according to their importance as environmental contaminants have been developed by government agencies and private industries. However, it has been noticed that few approaches, such as one published by the United States Environmental Protection Agency (USEPA), address the needs of the drinking water industry. There is also no generic approach to the selection, prioritisation and monitoring of organic contaminants in the drinking water value chain. To safeguard drinking water industry customers, it was necessary to develop a generic protocol to assist with the identification of a list of organic contaminants for monitoring in the drinking water value chain. Once the protocol was developed, it was validated in a prototype drinking water value chain. This paper describes the implementation of such a generic protocol. The exercise comprised of testing each step of the protocol, from selection of the &#8216;pool of organic contaminants&#8217; (Step I) to recommending the final priority list of organic contaminants (Step VII). Successful implementation of the protocol took place in the Rand Water (South Africa) drinking water value chain (from catchment to tap). Expert judgment was emphasized during the implementation as each step was validated and the opinion of key stakeholders used to shape the process. The tailor-made prioritisation criteria, reflecting the drinking water industry perspective, proved to be successful in selecting and prioritising organic contaminants for monitoring in the drinking water value chain. The organic contaminants were successfully prioritised in 3 classes: short-term priority for analysis, medium-term priority for analysis and long-term priority for analysis. This is a very important guide to assist water utilities in optimising their resources while not compromising the role of public health protection. Finally, a priority list of organic contaminants was identified for use by Rand Water and other water utilities.

Monitoring of organic contaminants in sediments from the Korean coast: Spatial distribution and temporal trends (2001–2007)

Spatial and temporal trends of organic contaminants in sediments along the Korean coast were estimated through a nationwide environmental monitoring program from 2001 to 2007. The concentrations of organic contaminants in sediments along the Korean coast were relatively low or moderate compared with foreign studies. The mean detection frequencies of organic contaminants during the seven years were highest for PAHs and PCDD/Fs, followed by PCBs, DDTs, TBT and HCHs in decreasing order. Based on published sediment quality guidelines, the ecological risks of persistent organic pollutants in sediments along the Korean coast were low, despite exceedances of the ERL at 2–6 sites for DDTs, and the TEL at 9–18 sites for PCDD/Fs. Nonparametric tests to assess temporal trends revealed significant decreasing trends for PCBs and PCDD/Fs at four and three sites, respectively (p<0.05). These results reflect the effects of regulations on the use of those contaminants.

On-line measurement of oxidative degradation kinetics for trace gasoline contaminants in aqueous solutions and natural water by membrane introduction tandem mass spectrometry

Membrane introduction mass spectrometry (MIMS) was used to directly monitor the loss of trace gasoline contaminants (benzene, toluene, 2-methylthiophene and methylcyclohexane) in nanomolar (ppb) aqueous solutions under a variety of UV-induced advanced oxidation processes (AOP). The decay kinetics of these contaminants were followed simultaneously in “real-time” via tandem mass spectrometric techniques by re-circulating the reaction mixture in a closed loop over a semi-permeable membrane interface. The photocatalyzed degradations were observed to follow pseudo–first-order kinetics with rate constants ranging from 0.006 to 0.2 min−1 depending on the reaction conditions. We report rate enhancements for several UV-based advanced oxidative processes using physisorbed titanium dioxide (TiO2/UV, TiO2/UV/O2, TiO2/UV/H2O2) and compare these to the direct photolysis of H2O2 under otherwise identical conditions. The relative degradation rates of 4 trace contaminants are reported for reactions carried out in the same solution. The degradation kinetics were also monitored directly in a natural surface water spiked with the same contaminant suite. The observed decay kinetics in the presence of TiO2 in air-saturated natural water were similar to those carried out in deionized water. However, when the photo-oxidation was enhanced by the addition of H2O2, the degradation was markedly slower in natural water relative to deionized water due to competition for photons by dissolved organic matter. This work further demonstrates the use of MIMS as a sensitive on-line measurement technique for “in-situ” reaction monitoring of organic contaminants at environmentally relevant concentrations in complex solutions and reactive media.

Applicability of spraints for monitoring organic contaminants in free‐ranging otters (Lutra lutra)

In the current study, the use of spraints for monitoring levels of polychlorinated biphenyls (PCBs) in individual otters was experimentally validated. On the basis of a detailed pattern analysis, it is concluded that in the current study, PCB concentrations in spraints that contain relatively high concentrations of nonmetabolizable PCB congeners (PCB 138 and 153 > 42.5% of total PCB concentrations) reflect the internal PCB concentrations of the otter that produced the spraint. In general, however, spraints should be selected that contain relative concentrations of PCB138 and PCB153 > 95th percentile of these congeners in samples from local food items of otters. On the basis of relationships between levels in spraints and internal levels and on earlier reported effect concentrations, a threshold level range of 1.0 to 2.3 microg/g (lipid normalized) in such spraints is proposed. The validated methods to monitor PCBs in otters may be combined with genetic marker techniques that can assess the identity of the otter that produced the spraints. In such a design, it is feasible to monitor PCB levels in individual free-ranging otters in a truly animal friendly way.

Performance of semipermeable membrane devices for sampling of organic contaminants in groundwater

Lipid-filled semipermeable membrane devices (SPMDs) are receiving increasing attention as passive, in situ samplers for the assessment of environmental pollutant exposure. Although SPMDs have been successfully used in a variety of field studies in surface waters, only a few studies have addressed their characteristics as groundwater samplers. In this study, the performance of the SPMDs for monitoring organic contaminants in groundwater was evaluated in a pilot field application in an area severely contaminated by chemical waste, especially by chlorinated hydrocarbons. The spatial distribution of hydrophobic groundwater contaminants was assessed using a combination of passive sampling with SPMDs and non-target semiquantitative GC-MS analysis. More than 100 contaminants were identified and semiquantitatively determined in SPMD samples. Along the 6 field sites under investigation, a large concentration gradient was observed, which confirms a very limited mobility of hydrophobic substances in dissolved form in the aquifer. The in situ extraction potential of the SPMD is limited by groundwater flow, when the exchange volume of well water during an exposure is lower than the SPMD clearance volume for the analytes. This study demonstrates that SPMDs present a useful tool for sampling and analyzing of groundwater polluted with complex mixtures of hydrophobic chemicals and provides guidance for further development of passive sampling technology for groundwater.

Charged Particle Activation Analysis of Carbon on Silicon Plates and Its Use for the Monitoring of Organic Contamination of the Air

Total carbon on the surface of silicon plates was determined by charged-particle activation with the 12C(d,n)13N reaction. A procedure was established for routine determination, including the methods for the transportation and bombardment of the sample without disturbing the surface carbon and for the separation of the 13N. Silicon plates, after undergoing different surface treatments, were exposed to the air in clean rooms and ordinary living areas, and the surface carbon was analyzed to evaluate the usefulness of this method and to get information required in the semiconductor industry. Surface carbon of (0.2−3) × 1015 atoms/cm2 was found on silicon plates left in usual nonsmoking rooms after any treatment; it was reduced to 5 × 1012 atoms/cm2 by heating to 900 °C for 30 min in purified air and was then kept under 1 × 1013 atoms/cm2 for a few days in high-grade clean rooms. Etching with NH4OH/H2O2 or a fluoride-containing reagent often gave higher and varying surface-carbon quantities. This method of analysis is sensitive to 1 × 1012 atoms/cm2 of total carbon and is hoped to offer meaningful information concerning clean rooms and to be utilized generally for monitoring carbonaceous air pollution.

Semi permeable membrane devices (SPMDS) for monitoring organic contaminants in the Otonabee River, Ontario

Semi-permeable membrane devices (SPMDs) were deployed for 4 weeks (May-June, 1994) at 8 sites in the Otonabee River, Ontario, Canada, and subsequently extracted for analysis of PCBs and polynuclear aromatic hydrocarbons (PAHs). The concentrations of PCBs were elevated in the SPMDs deployed in Little Lake at the upstream end of this system, which reflects continuing discharges and in-place PCB contamination in this urban area. However, at sites downstream from Little Lake, the concentrations of PCBs increased with distance downstream; indicating either another point-source of PCBs or spatial variations in the partitioning of these compounds into the dissolved phase. The spatial patterns for PAH contamination were similar to PCBs. At one site in Little Lake, SPMDs were collected at 2, 4 and 6 weeks after deployment and these temporal contaminant data are consistent with enhanced uptake ofPCBs and some hydrophobic PAHs as water temperature increased. These data indicate that SPMDs are useful in situ monitoring devices for determining spatial trends in the contamination of the aquatic environment, but several factors can modify rates of uptake into these devices.

Passive sampler for chlorinated pesticides in estuarine waters

Monitoring organic contaminants in the marine environment and identifying their bioconcentration pathways presents great difficulties, as the analytical techniques require preconcentration steps th...

Lipid-containing semipermeable membrane devices for monitoring organic contaminants in water

A semipermeable membrane device (SPMD) is described for passive in-situ monitoring of organic contaminants in water. The device consists of a thin film of neutral lipid (molecular mass generally ≥600 Da), such as triolein, enclosed in thin-walled layflat tubing made of low-density polyethylene or another nonporous polymer. Mathematical models are developed for the device and fitted to concentration data from 2,2',5,5'-tetrachlorobiphenyl and phenanthrene flow-through exposures and dissipation experiments. Model estimates of the average concentrations of test chemical in laboratory exposure water differed from the measured concentrations by <2-fold, indicating that it may be feasible to use the device to determine average concentrations of organic contaminants in natural waters

A fiber optic evanescent field absorption sensor for monitoring organic contaminants in water

A fiber optic chemical sensor for determination of organic compounds in aqueous solution has been developed. Based on the evanescent field principle, a quartz glass fiber with a polysiloxane cladding is used as in-situ measuring probe. A compact sensor built from a 6-m coiled fiber has been connected to a commercially available fast scanning dispersive NIR spectrometer. The siloxane cladding fulfils two functions: on the one hand, it acts as protecting layer of the fragile silica fiber core, and on the other hand, it is selective with respect to non-polar organic compounds due to its organophilic properties. Hence, interactions of the evanescent field at the core/cladding interface with organic species penetrating into the cladding can be measured without interferences from broad water OH absorption bands. Aqueous solutions of chlorinated hydrocarbon solvents (CHS) have been used to test the sensor response. NIR evanescent field absorbance spectra of methylene chloride, chloroform and trichloroethylene diffused into the fiber cladding are shown in the 900–2100 nm spectral range. Different amounts of CHCl3 dissolved in water have been determined in order to evaluate the quantitative sensor response. A linear absorbance/concentration relationship has been found for solutions between 80–6800 mg l−1. Kinetic experiments performed with CHCl3 solutions resulted in sensor response times of 5–10 min. The sensor seems to be promising for the remote monitoring of organic contaminants, e.g. CHS, in drainage waters of contaminated areas.