An updated status of currently used pesticides in India: Human dietary exposure from an Indian food basket.

Currently used pesticides (CUPs) were introduced to have lower persistence and bioaccumulation, and lesser bioavailability towards non-target species. Nevertheless, CUPs still represent a concern for both human health and the environment. India is an important agricultural country experiencing a conversion from the use of obsolete organochlorine pesticides to a newer generation of phytosanitary products. As for other developing countries, very little is known about the transfer of CUPs to the human diet in India, where systematic monitoring is not in place. In this study, we analyzed ninety four CUPs and detected thirty CUPs in several food products belonging to five types: cereals and pulses, vegetables, fruits, animal-based foods, and water. Samples were taken from markets in Delhi (aggregating food produced all over India) and in the periurban area of Dehradun (northern India) (representing food produced locally and through more traditional practices). Overall, chlorpyrifos and chlorpropham were the most detected CUPs with a detection frequency of 33% and 25%, respectively. Except for vegetables and fruits, the levels of CUPs in all other food types were significantly higher in samples from Delhi (p < 0.05). Exposure dosage of CUPs through different food matrices was calculated, and chlorpropham detected in potatoes had the maximum exposure dosage to humans (2.46 × 10-6 mg/kg/day). Risk analysis based on the hazard quotient technique indicated that chlorpyrifos in rice (2.76 × 10-2) can be a concern.

Determination of chlorpropham (CIPC) residues, in the concrete flooring of potato stores, using quantitative (HPLC UV/VIS) and qualitative (GCMS) methods.

Isopropyl-N-(3-chlorophenyl) carbamate (CIPC, common name Chlorpropham) is commonly used for post-harvest sprout inhibition in stored potatoes. It is applied as a thermal fog which results in loss to the fabric of the store and the atmosphere. Recently, there have been concerns in the United Kingdom because of cross contamination of other crop commodities that were stored in buildings with a history of CIPC usage. This cross contamination may have occurred because of retained residues in the fabric of the stores. The retention of CIPC in concrete is poorly understood; therefore the requirement for a robust analytical method for the detection and quantification of CIPC in concrete is a critical first step in tackling this problem. A method using High-Performance Liquid Chromatography with ultraviolet detection (HPLC UV/VIS) was validated. CIPC recoveries at three concentration levels (0.4, 4.0 and 40.0 µg g-1) were in the range of 90.7-97.0% with relative standard deviations between 2.14 and 3.01%. The limits of detection and quantification were 0.03 and 0.1 µg g-1, respectively. This study confirmed that CIPC was persistent in concrete to a depth of 4 cm, with >90% within the top 1 cm of the flooring.

Direct detection of chlorpropham on potato skin using desorption electrospray ionization.

Most pesticides, herbicides and other plant treatment agents are applied to the crop surface. Direct mass spectrometric methods, such as desorption electrospray ionization (DESI), offer new ways to analyze plant samples directly and rapidly. A strategy for the development and optimization of a DESI method for the direct determination of chemicals on complex surfaces is described. Chlorpropham (CP) was applied to potato surfaces as an example for a crop protection agent and analyzed using a self-made DESI source. Aspects such as instrument selectivity, sensitivity and reproducibility were investigated. The MS(4) fragmentation pattern of CP was analyzed to achieve the necessary detection selectivity, and is discussed in detail. Similar fragmentation was found in the ESI and DESI mass spectra, indicating that the mechanisms of ESI and DESI are closely related. A DESI method for semi-quantification of CP on potatoes was developed. Detection limits of 6.5 µg/kg were found using MS/MS. The reproducibility, in the range of 12% (signal variation), appears to be sufficient for semi-quantitative measurements.

Tools to study the degradation and loss of the N-phenyl carbamate chlorpropham--a comprehensive review.

Chlorpropham (CIPC) was introduced in 1951 and is a primary N-phenyl carbamate belonging to a group of pesticides known as carbamates which are estimated to account for 11% of the total insecticide sales worldwide. They were considered less toxic than organochlorines due to their easier breakdown but, subsequent concerns regarding the environmental impact and their breakdown products have shown them to be environmental toxins and toxic and/or carcinogenic for humans. CIPC is used in growing crops to control weeds and also as a sprout suppressant on crops during long-term storage and while its degradation has been studied and rates quoted these vary greatly. Here published rates of degradation by hydrolysis, biolysis, photolysis and thermal processes are reviewed as well as data on partitioning in air, water and soil. In addition the details of the experimental procedures are reviewed and compared showing how the half-lives and partitioning coefficients have been calculated leading to an understanding of how such vastly different values are achieved. The legislation regarding the use of CIPC and its maximum residue level is also discussed particularly in reference to recent European Commission (EC) legislation. In view of the fact that analytical data on the breakdown of CIPC play an important role in decision-making by regulatory agencies, the authors feel that it is time for an up-to-date review of the data available, including very recent developments in methodology.

Planktonic versus biofilm catabolic communities: importance of the biofilm for species selection and pesticide degradation.

Chloropropham-degrading cultures were obtained from sludge and soil samples by using two different enrichment techniques: (i) planktonic enrichments in shaken liquid medium and (ii) biofilm enrichments on two types of solid matrixes (plastic chips and gravel). Denaturing gradient gel electrophoresis fingerprinting showed that planktonic and biofilm cultures had a different community composition depending on the presence and type of added solid matrix during enrichment. This was reflected in the unique chloropropham-degrading species that could be isolated from the different cultures. Planktonic and biofilm cultures also differed in chloropropham-degrading activity. With biofilm cultures, slower chloropropham removal was observed, but with less build-up of the toxic intermediate 3-chloroaniline. Disruption of the biofilm architecture resulted in degradation characteristics shifting toward those of the free suspensions, indicating the importance of a well-established biofilm structure for good performance. These results show that biofilm-mediated enrichment techniques can be used to select for pollutant-degrading microorganisms that like to proliferate in a biofilm and that cannot be isolated using conventional shaken-liquid procedures. Furthermore, the influence of the biofilm architecture on the pesticide degradation characteristics suggests that for bioaugmentation the use of biofilm catabolic communities might be a proficient alternative to using planktonic freely suspended cultures.

[Survey of pesticide residues in imported frozen vegetables and fruits (1989.4~2008.3)].

A survey of pesticide residues in 595 imported frozen products on the Tokyo market from April 1989 to March 2008 was carried out. Forty three kinds of pesticides, including organophosphorus, organochlorine, carbamate, pyrethroid and others, were detected between levels of trace (below 0.01 ppm) and 4.6 ppm from 162 samples. Chlorpyrifos, cypermethrin and omethoate were frequently detected in green vegetables (komatsuna leaf and spinach), cypermethrin and methamidophos were detected in pods and seeds (green soybean and string pea), chlorpropham (CIPC) was detected in potato, and captan and carbaryl were detected in berries (blueberry, raspberry and strawberry). The hydrophilic pesticide methamidophos was detected in flesh of lychee. Residue levels of these pesticides were calculated as between less than 0.5% and 30% of their ADI values according to the daily intake of frozen products. Therefore, these frozen products should be safe when they were eaten in customary amounts.

Level and fate of chlorpropham in potatoes during storage and processing.

Chlorpropham (isopropyl 3-chlorocarbanilate) is a pesticide used to control sprouting of potatoes during long-term storage. The objective of the present study was to establish the total chlorpropham residue balance (residues in unwashed and washed whole tubers, peeled tubers, peels, boiled and pureed tubers, and washing and cooking waters) for two potato varieties after uniform application as a function of storage time under different typical storage conditions (in a basement, storehouse, and refrigerator) in Lithuania. Chlorpropham concentration on washed and unwashed tubers decreased from approximately 15 mg kg(- 1) after storage for 28 d to approximately 9 mg kg(- 1) after storage for 85 d. Peel concentrations decreased from approximately 50 mg kg(- 1) at 5 d after treatment to approximately 20 mg kg(- 1) at 85 d after treatment. The average concentration in the two varieties of peeled tubers in the three storage facilities was 1 mg kg(- 1). Chlorpropham concentrations in the wash water decreased from 3.5 to 1.0 mg L(- 1) when the storage time increased from 28 to 85 d. The cooking water concentration similarly decreased, from > 0.2 mg L(- 1) at 28 d after treatment to > 0.1 mg L(- 1) at 85 d after treatment. The results of this study show that chlorpropham concentrations in tubers under these typical conditions were below the recently revised levels that are acceptable for residues in whole potatoes (30 mg kg(- 1)) and peels (40 mg kg(- 1)). Also, despite fluctuating conditions during storage, chlorpropham treated tubers did not sprout, as compared to untreated tubers, which sprouted.

Assessment of uncertainty in a probabilistic model of consumer exposure to pesticide residues in food.

The assessment of consumer exposure to pesticides is an important part of pesticide regulation. Probabilistic modelling allows analysis of uncertainty and variability in risk assessments. The output of any assessment will be influenced by the characteristics and uncertainty of the inputs, model structure and assumptions. While the use of probabilistic models is well established in the United States, in Europe problems of low acceptance, sparse data and lack of guidelines are slowing the development. The analyses in the current paper focused on the dietary pathway and the exposure of UK toddlers. Three single food, single pesticide case studies were used to parameterize a simple probabilistic model built in Crystal Ball. Data on dietary consumption patterns were extracted from National Diet and Nutrition Surveys, and levels of pesticide active ingredients in foods were collected from Pesticide Residues Committee monitoring. The effect of uncertainty on the exposure estimate was analysed using scenarios, reflecting different assumptions related to sources of uncertainty. The most influential uncertainty issue was the distribution type used to represent input variables. Other sources that most affected model output were non-detects, unit-to-unit variability and processing. Specifying correlation between variables was found to have little effect on exposure estimates. The findings have important implications for how probabilistic modelling should be conducted, communicated and used by policy and decision makers as part of consumer risk assessment of pesticides.

The heterogeneity of sprout inhibitor application with chlorpropham.

The CIPC or chlorpropham is used on potatoes as "sprouting inhibitor". These lasts years, some set of belgian potatoes treated by CIPC exceeded the Maximum Residue Limit (MRL), fixed at 5 mg/kg. The heterogeneity of sprout inhibitor application would be one of the causes of over-dosage. In order to estimate the distribution of CIPC between potatoes, according to the formulation used (DP, EC and HN), a research project financed by "le fond budgétaire des matières premieres" has been set up. In order to evaluate the distribution of CIPC into the pile of potatoes, the efficiency of the different formulations as well as the residues caused by their application on tubers, some tests have been placed in the storage hall. These tests consist in taking off some samples at different places into the pile of potatoes during storage and destocking. The content of CIPC is analysed by capillary gas chromatography with detection by mass spectrometry detection (GC-MS) or nitrogen specific detection (GC-NPD). To estimate the efficiency, the sprouting are observed every month and samples of potatoes are taken off on the top of the pile to control the evolution of CIPC content. Considering the results of the tests, the inhibitor treatment with the formulation DP+HN seems to be the more efficient. As for the residues, the formulation DP leads to a higher content of CIPC than HN, that has a very low concentration. After treatment, the quantity really applied on tubers depends on the formulation used. In fact, 50% of CIPC applied by DP formulation are found on tubers but hardly 10%, after gas application.

Residue levels of chlorpropham in individual tubers and composite samples of postharvest-treated potatoes.

Chlorpropham, a herbicide and sprout suppressant, is used on stored potatoes to prolong the storage period without deterioration of produce quality. Data for residue concentrations on an individual tuber basis are required by WHO for the estimation of the variability factor. In this study, the levels of chlorpropham in individual tubers and in composite samples were determined. The distribution of chlorpropham between the peel and the tuber flesh was examined, and the fate during the cooking process (washing, boiling, frying) was studied. The concentrations in individual tubers ranged from 1.8 to 7.6 mg/kg 10 days postapplication (mean 3.8 mg/kg, RSD 39%), from 0.7 to 4.0 mg/kg 28 days postapplication (mean 2.9 mg/kg, RSD 28%), and from 0.8 to 3.8 mg/kg 65 days postapplication (mean 2.2 mg/kg, RSD 48%). The calculated residues in composite samples 10 days postapplication ranged from 4.3 to 6.1 mg/kg (mean 4.9 mg/kg, RSD 20%). Those in samples taken 28 days postapplication ranged from 3.1 to 4.2 mg/kg (mean 3.8 mg/kg, RSD 15%). The concentrations determined in composite samples of whole tubers 65 days postapplication ranged between 2.6 and 3.2 (mean 2.9 mg/kg, RSD 11%). Peeling removed 91-98% of the total residue; washing reduced residues by 33-47%. Detectable residues were found in boiled potatoes and the boiling water, and in french fries and the frying oil. Monitoring data on commercial prefried frozen french fries are reported.

Some applications of solid phase micro extraction (SPME) in the analysis of pesticide residues in food.

The Solid Phase Micro-Extraction (SPME) technique was applied to analyze chlorpropham in potatoes and amitraz in honey. The homogenized sample, suspended in water and stirred, was extracted with a 100 microns thick polidimetylsiloxane fiber and desorbed into the injection port of a gas chromatograph/mass-spectrometer (quadrupole) operating in single ion monitoring. Sensitivities down to 0.01 mg/Kg and linear responses in the range of 0.01-0.1 mg/Kg were obtained. The results of SPME pesticide residue analysis in potatoes corresponded to those obtained with a traditional multiresidue method.

The carry-through of residues of thiabendazole, tecnazene and chlorpropham from potatoes following manufacture into potato crisps and jacket potato crisps.

Potatoes, commercially treated with thiabendazole, tecnazene and chlorpropham, were processed into potato crisps and jacket potato crisps at a crisp factory using standard manufacturing conditions. A multi-residue method based on gas chromatography with mass spectrometric detection was developed and used to determine pesticide residue levels in the potatoes and potato crisps. Results showed that the residues of all three pesticides were significantly reduced to less than 2% and less than 10% of the maximum theoretical residue carry-through level for potato crisps and jacket potato crisps respectively.

A simple and quick gas chromatographic method for the determination of propham and chlorpropham in potatoes.

This study describes a gas chromatographic method for the quantitative determination of residual propham and chlorpropham in potatoes. Both herbicides are extracted from the foodstuff with methylene chloride. After centrifugation and concentration, propham and chlorpropham are quantitatively determined by gas chromatography thermionic detection using a fused silica capillary column CP Sil 5CB. 2-Chloraniline is used as internal standard. Recoveries of 100 +/- 15% and 99 +/- 10% have been obtained for propham and chlorpropham in blank samples spiked at the level of 0.5, 1.0 and 5.0 mg/kg. The absolute detection limit for both compounds is 1 ng corresponding to 0.1 mg/kg. Of the 161 samples of fresh potatoes analysed using this method, 136 contained residues of these herbicides and 18 of them (11%) exceeded the maximum tolerated value of 5 mg/kg.

Comparison of an HPTLC and an HPLC procedure for the determination of chlorpropham, propham and thiabendazole residues in potatoes.

HPTLC was used to check for residues of chlorpropham, propham (sprout inhibitors) and thiabendazole (fungicide) applied to potatoes. The method used gave good precision and analytical sensitivity. The sample preparation method developed by the authors was simple and gave good recovery and selectivity as far as other components of the matrix were concerned. Comparison with liquid chromatography confirmed the validity of the results.