Chloramination of organophosphorus pesticides found in drinking water sources

The degradation of commonly detected organophosphorus (OP) pesticides, in drinking water sources, was investigated under simulated chloramination conditions. Due to monochloramine autodecomposition, it is difficult to observe the direct reaction of monochloramine with each OP pesticide. Therefore, a model was developed to examine the reaction of monochloramine (NH₂Cl) and dichloramine (NHCl₂) with chlorpyrifos (CP), diazinon (DZ), and malathion (MA). Monochloramine was found not to be very reactive with each OP pesticides, . While, dichloramine (NHCl₂) was found to be 2 orders of magnitude more reactive with each of the OP pesticides than monochloramine, , which is still three orders of magnitude less than the hypochlorous acid reaction rate coefficient with each OP pesticide. For each pesticide, the reactivity of the three chlorinated oxidants was then found to correlate with half-wave potentials (E_1/2) of each oxidant. With reaction rate coefficients for the three chlorinated oxidations as well as neutral and alkaline hydrolysis rate coefficients for the pesticides, the model was used to determine the dominant reaction pathways as a function of pH. At pH 6.5, OP pesticide transformation was mostly due to the reaction of hypochlorous acid and dichloramine. Above pH 8, alkaline hydrolysis or the direct reaction with monochloramine was the primary degradation pathway responsible for the transformation of OP pesticides. This demonstrates the ability of models to be used as tools to elucidate degradation pathways and parameterize critical reaction parameters when used with select yet comprehensive data sets.     

Isolation and characterization of bacterial strains capable of growing on malathion and fenitrothion and the use of date syrup as an additional substrate

Four bacterial strains capable of growing on two organophosphorus pesticides (malathion and fenitrothion) were isolated from activated sludge. Among these isolates, the species Stenotrophomonas maltophilia was found to be capable of using fenitrothion as the sole carbon and nitrogen source, and malathion as the sole carbon source. There appear to be no similar reported findings. A crude juice of dates was tested as an additional carbon source for malathion degradation. The biodegradability was significantly enhanced with the supplementation of date juice. The degradation efficiency of the pesticide tested at a concentration of 60 mg/L reached the maximum value of 89% in the presence of date juice at 30 g/L reducing sugar. Statistical screening of four operating parameters (initial biomass concentration, aeration rate, agitation and temperature) for biomass growth and for malathion degradation by acclimated indigenous activated sludge was carried out using a fractional factorial design.     

Human Exposure to Airborne Pesticides in Homes Treated with Wood Preservatives

Abstract In rooms where pesticides were applied, air was analysed for its biocide content. Inhabitants of investigated homes attributed their health complaints to pesticide exposure in their homes. Airborne pesticides originating from wood preservatives were sampled on polyurethane foams or Tenax TA and analysed after solvent desorption by HRGC with different types of detector. In investigated homes, concentrations of diazinon, phenthoate, phoxim, propoxur, dichlofluanid, endosulfan, permethrin and tributyltinoxide were found between ≤0.002 and 0.347 μg/m³. In one home, four years after pest control, chlorpyrifos amounted to 0.515 μg/m³. Permethrin emission from a wool carpet ranged between 0.013 and 0.060 μg/m³. Vacuum cleaning for ten minutes increased airborne permethrin up to 0.096 μg/m³. In house dust, diazinon, phenthoate and permethrin were determined in concentrations of 0.60 ≤g/g, 181.00 pg/g and 0.14 μg/g dust, respectively. Estimated inhaled pesticides ranged between ≤0.04 and 10.3 μg/day. Dust ingestion contributed to 0.03–36.2 μg/day. Pesticide intake through inhalation and dust ingestion was estimated to range between 4% and 120% of the ADI-value. Based on today's knowledge, toxic effects are not anticipated.     

Removal of organophosphate pesticides from wastewater by supercritical carbon dioxide extraction

Organophosphate pesticides including fenitrothion chlorpyrifos, diazinon, methamidophos, edifenphos, mevinphos, fenthion, and acephate present in agro-wastewater can be effectively removed by supercritical carbon dioxide (SC-CO2) extraction. Near quantitative removal of the pesticides from the aqueous solution can be achieved by SC-CO2 at 90 degrees C and 325 atm for 20 min of static extraction followed by 40 min of dynamic extraction. The extracted pesticides were collected in a small amount of Fenton's solution. The pesticides in Fenton's solution were degraded completely within an hour after the collection. A combination of SC-CO2 extraction and subsequent degradation by Fenton's reagent may provide an alternative water purification strategy for treating organophosphate pesticides in agro-wastewater.     

Effects of chlorine on organophosphorus pesticides adsorbed on activated carbon: desorption and oxon formation

We investigated effects of chlorination on four organophosphorus pesticides (diazinon, isoxathion, malathion, and tolclofos-methyl) adsorbed on powdered activated carbon (PAC). Following adsorption of each pesticide on 10mg/L of PAC in water, chlorine was added. After 30min of chlorination, the corresponding oxons were detected in the water, but the parent compounds were not detected. Molar ratios of the oxon concentration in solution after 30min of chlorine addition to the initial pesticide concentration before the adsorption process were 4.1% and 7.9% for diazinon, 3.9% and 5.8% for isoxathion, 1.2% and 1.7% for malathion, and 1.4% and 1.4% for tolchlofos-methyl, in the case of 2 and 5mg/L of chlorine addition. The results suggested that the oxons were desorbed from the PAC by chlorination. The concentrations of the desorbed oxons gradually decreased with time, apparently owing to their readsorption by the PAC. Results from additional experiments suggest the following sequence of events: (i) adsorbed pesticides are oxidized by chlorine on the surface of the PAC and transformed into corresponding oxons; (ii) the oxons are released from the PAC; (iii) the released oxons are gradually readsorbed by the PAC, decreasing their concentrations in the water phase.     

Comparative ecological risks of pesticides used in plantation production of papaya: application of the SYNOPS indicator

Pesticides are used intensively for crop protection in tropical fruit plantations. Assessments of the relative risks posed by pesticides are needed to assist in the development of management plans that minimize ecological impacts. In this study, the risk indicator SYNOPS_2 was used to compare risks to aquatic ecosystems by pesticides commonly used in papaya plantations. Plant interception and spray drift were measured during six applications of three pesticides (chlorothalonil, chloropyrifos, and malathion) using a turbo fan driven sprayer. Plant interception was estimated to be higher (42.6+/-12.7%; p=0.04) in late (8-14 months old) than in early (4 months old) trees (20.1+/-25.3%). Chlorothalonil concentrations of up to 11.0 microg L(-1) were found in water from an adjacent ditch after field application. Concentrations of this pesticide (7.4+/-4.1 microg L(-1)) in runoff water were also significantly (p<0.01) higher than those of malathion (2.4+/-1.9 microg L(-1)) and chlorpyrifos (0.8+/-0.5 microg L(-1)). Good correlation between measured and predicted values (r2=0.56-0.85, p<0.01) showed that SYNOPS_2 is able to describe trends in runoff pollution in papaya plantations. Linear equations were obtained in order to correct numerical disagreement between measured and calculated runoff concentrations. An independent test showed a reasonable agreement between measured chlorothalonil concentrations and the predicted values using the proposed equations. Fifteen pesticides used in papaya cultivation were ranked according to their calculated chronic biological risk index. Pesticides with the highest risk index for non-target organisms were: chlorothalonil for algae, lambda cyahalotrin for Daphnia and fish, and malathion for earthworms. Chlorothalonil was the pesticide with the highest exposure level in water and therefore represents a high risk for aquatic life. Results show that SYNOPS_2 can be used as a pesticide risk indicator on papaya and possibly other tropical fruit plantations.     

Dissipation of insecticides in a Mediterranean soil in the presence of wastewater and surfactant solutions. A kinetic model approach

The simultaneous disappearance of four organophosphorous insecticides in a Mediterranean calcareous soil was evaluated in the presence of surfactant solutions and municipal wastewater. A cationic, an anionic and a non-ionic surfactant were used at a low (0.75 mg L⁻¹) and at a high (twice the critical micelle concentration) concentration level. The cationic surfactant was also studied at a higher concentration. Dissipation in control soil was rapid for malathion (half-life 4 days), intermediate for dimethoate and methidathion (ca. 6 days) and slow for diazinon (29 days). Wastewater did either not modify (diazinon, dimethoate and methidathion) or slightly enhance (malathion) insecticide decay. The increase in concentration of the non-ionic surfactant Tween 80 resulted in enhanced dissipation rates for all the pesticides except diazinon. The addition of the anionic surfactant did not show a clear trend. At the highest cationic surfactant concentration a reduction of pesticide disappearance occurred linked with a reduced availability, since the insecticides were retained on the surfactant-modified soil (final residual concentration of 85% for diazinon and ≈55% for methidathion and dimethoate). Soil microbial activity, estimated by measuring dehydrogenase activity, was low in wastewater- and surfactant-treated soil at the high levels. Fitting of the experimental data to commonly used mathematical models was poor and alternatives were looked for.     

Concentration and loading of pesticide residues in Lake Biwa basin (Japan).

The concentrations and loading rates of pesticides used in paddy fields were investigated over a period of 5 years in the Seta River, which is the only natural outlet of Lake Biwa. The lake's water catchment area is 3,174 km2, 20% of which contains paddy fields. Water samples were also collected in six rivers flowing into the lake in order to compare the contamination level and concentration profile. The pesticides analyzed were four herbicides (molinate, simetryn, oxadiazon, and thiobencarb), one fungicide (isoprothiolane), and two insecticides (diazinon and fenitrothion). Molinate, simetryn, oxadiazon and isoprothiolane were found at the higher frequencies with maximum concentrations of 1.1, 0.4, 0.1 and 0.5 microg,/l in the effluent river, one or two order of magnitude higher than that of effluent in influent rivers. These peak concentrations were observed during the application period in influent rivers and two or three weeks after that in effluent river. The frequency of occurrence of thiobencarb, diazinon, and fenitrothion was relatively low and their maximum concentrations in the effluent remained below 0.1 microg/l. The decrease of molinate, simetryn and oxadiazon concentrations in the effluent river were approximated by two straight lines plotted on semilogarithmic scale. Increased loading was induced by intense rainfall, which took place during the application period. Simetryn and isoprothiolane persisted in relatively high concentrations through the year were also influenced on its loading by the heavy rainfall in the following months. The percentages of the total amount of pesticides released through Lake Biwa to the basin in downstream were estimated to be 1.3-2.9% for molinate, 5.4-10.0% for simetryn, 0.6-1.3% for oxadiazon, 0.2-0.9% for thiobencarb, 1.8-6.6% for isoprothiolane, 0.3-2.1% for diazinon. and 0% for fenitrothion.     

Occurrence of pesticides in rain and air in urban and agricultural areas of Mississippi, April-September 1995

In April 1995, the US Geological Survey began a study to determine the occurrence and temporal distribution of 49 pesticides and pesticide metabolites in air and rain samples from an urban and an agricultural sampling site in Mississippi. The study was a joint effort between the National Water-Quality Assessment and the Toxic Substances Programs and was part of a larger study examining the occurrence and temporal distribution of pesticides in air and rain in the Mississippi River basin. Concurrent high-volume air and wet-only deposition samples were collected weekly. The air samplers consisted of a glass-fiber filter to collect particles and tandem polyurethane foam plugs to collect gas-phase pesticides. Every rain and air sample collected from the urban and agricultural sites had detectable levels of multiple pesticides. The magnitude of the total concentration was 5-10 times higher at the agricultural site as compared to the urban site. The pesticide with the highest concentration in rain at both sites was methyl parathion. The pesticide with the highest concentration in the air samples from the agricultural site was also methyl parathion, but from the urban site the highest concentration was diazinon followed closely by chlorpyrifos. More than two decades since p,p'-DDT was banned from use in the United States, p,p'-DDE, a metabolite of p,p'-DDT, was detected in every air sample collected from the agricultural site and in more than half of the air samples from the urban site.     

Pesticides in the atmosphere of the Mississippi River Valley, part II--air

Weekly composite air samples were collected from early April through to mid-September 1995 at three paired urban and agricultural sites along the Mississippi River region of the Midwestern United States. The paired sampling sites were located in Mississippi, Iowa, and Minnesota. A background site, removed from dense urban and agricultural areas, was located on the shore of Lake Superior in Michigan. Each sample was analyzed for 49 compounds; of these, 21 of 26 herbicides, 13 of 19 insecticides, and 4 of 4 related transformation products were detected during the study, with most pesticides detected in more than one sample. The maximum number of pesticides detected in an air sample was 18. Herbicides were the predominant type of pesticide detected at every site. Detection frequencies of most herbicides were similar at the urban and agricultural sites in Iowa and Minnesota. In Mississippi, herbicides generally were detected more frequently at the agricultural site. The insecticides chlorpyrifos, diazinon, and carbaryl, which are used in agricultural and non-agricultural settings, were detected more frequently in urban sites than agricultural sites in Mississippi and Iowa. Methyl parathion was detected in 70% of the samples from the Mississippi agricultural site and at the highest concentration (62 ng/m3 air) of any insecticide measured in the study. At the background site, dacthal (100%), atrazine (35%), cyanazine (22%), and the (primarily atrazine) triazine transformation products CIAT (35%) and CEAT (17%) were detected most frequently, suggesting their potential for long-range atmospheric transport.     

Organochlorine and organophosphorus insecticides: Their use in eleven agricultural watersheds and their loss to stream waters in Southern Ontario,Canada, 1975–1977

As part of a comprehensive study of the effects of agricultural land use activities on the quality of water entering the Great Lakes, 949 stream water samples from 11 agricultural watersheds in southern Ontario were collected in 1975–1977 and analyzed for organochlorine and organophosphorus insecticide residues which were currently in use in those watersheds. Detectable residues of chlordane, heptachlor epoxide, and endosulfan were found in 1.6, 6.0, and 19.3% of samples, respectively. Over 50% of the total organochlorine insecticides were found to be transported in the January-to-April periods corresponding to spring thaws, low ground cover, and high suspended solids in the water. Unit area loadings ranged from 0 to 4.5 mg/ha/yr for chlordane plus heptachlor epoxide and 0 to 89.9 mg/ha/yr for endosulfan. Water quality objectives proposed by the International Joint Commission were exceeded in 4% of samples by heptachlor epoxide, and 14% of samples by endosulfan.Sixteen organophosphorus insecticides were known to be used in the watersheds but only chlorpyrifos, diazinon, ethion, and malathion were detected. Chlorpyrifos was present in only three samples, ethion in two, and malathion in four; 87 samples were found to contain diazinon but 64 of these were identified as originating from an indoor (non land-use) activity in one watershed. All field losses of organophosphorus insecticides occured in the May-August period correlating with the season of application. Proposed I.J.C. water quality objectives were exceeded in one sample where diazinon was used in land activities and in 77 samples as the result of diazinon being used in an indoor activity. No other organophosphorus insecticides were found which exceeded the proposed water quality objectives.     

Evaluation of water quality in an agricultural watershed as affected by almond pest management practices

In the last decade, the detection of organophosphate (OP) pesticides in the San Joaquin River watershed has raised concerns about water quality. This study examined the influences of almond pest management practices (PMPs) on water quality. The Soil and Water Assessment Tool (SWAT) model was employed to simulate pesticide concentration in water as affected by different PMPs. California Pesticide Use Reporting (PUR) data were used to investigate PMP use trends. Stepwise regression analysis was performed to test the correlation between specific PMP use and pesticide concentrations in surface water and sediment. Our results showed an increasing use of reduced risk pesticides and pyrethroids on almonds. SWAT simulation over the period of 1992-2005 showed decreases in OP concentrations in surface water. High OP and pyrethroid use in dormant sprays was associated with high pesticide concentrations in water and sediment. Almond pesticide use was proved to have significant impacts on the pesticide load in the San Joaquin River watershed. The PMP which combines the use of reduced risk pesticides with no dormant spray was recommended for almond orchard use. This paper presented a novel method of studying the environmental impacts of different agricultural PMPs. By combining pesticide use surveys with watershed modeling, we provided a quantitative foundation for the selection of PMPs to reduce pesticide pollution in surface water.     

Modeling effectiveness of agricultural BMPs to reduce sediment load and organophosphate pesticides in surface runoff

Quantifying effectiveness of agricultural BMPs at the watershed scale is a challenging issue, requiring robust algorithms to simulate not only the agricultural production system but also pollutant transport and fate. This research addresses the challenge to simulate performances of BMPs in reducing organophosphates (OPs) runoff at the watershed scale. The SWAT model is calibrated and validated following a sensitivity analysis combining Latin Hypercube sampling and One-factor-At-a-Time simulation. The calibrated model is then applied in the Orestimba Creek Watershed to simulate BMPs including buffer strips, sediment ponds, vegetated ditches, use reduction, and their combinations. BMP simulation suggested that sediment ponds trap 54-85% of sediment from field runoff, but less than 10% of dissolved diazinon and chlorpyrifos. Use reduction can reduce pesticide load in a close-to-linear fashion. Effectiveness of vegetated ditches and buffers depends on their physical dimension and vegetation cover. Combining individual BMPs provides enhanced mitigation effects. The combination of vegetated ditches, buffer strips and use reduction decreases diazinon and chlorpyrifos load by over 94%. This study has suggested that the SWAT model reasonably predicts BMP effectiveness at the watershed scale. Results will assist decision making in implementing BMPs to reduce pesticide loads in surface runoff.     

Pesticide exposure of non-occupationally exposed subjects compared to some occupational exposure: a French pilot study

Data about non-dietary exposure to different chemical classes of pesticides are scarce, especially in France. Our objective was to assess residential pesticide exposure of non-occupationally exposed adults, and to compare it with occupational exposure of subjects working indoors. Twenty unexposed persons, five gardeners, seven florists and nine veterinary workers living in Paris area were recruited. Nineteen residences, two greenhouses, three florist shops and three veterinary departments were then sampled. Thirty-eight insecticides, herbicides and fungicides were measured in indoor air with an air sampler for 24 h, and on hands by wiping them with isopropanol-wetted swabs. After extraction, samples were analysed by gas and high-performance liquid chromatography. Seventeen different pesticides were detected at least once in indoor air and twenty-one on the hands. An average of 4.2+/-1.7 different pesticides was detected per indoor air sample. The organochlorines lindane, alpha-endosulfan and alpha-HCH were the most frequently detected compounds, in 97%, 69% and 38% of the samples, respectively. The organophosphates dichlorvos and fenthion, the carbamate propoxur and the herbicides atrazine and alachlor were detected in more than 20% of the air samples. Indoor air concentrations were often low, but could reach 200-300 ng/m(3) in residences for atrazine and propoxur. Propoxur levels significantly differed between the air of veterinary places and other places (Kruskal-Wallis test, p<0.05) and dieldrin levels between residences and workplaces (p<0.05). There was a greater number of pesticides on hands than in air, with an average of 6.3+/-3.3 different pesticides detected per sample, the most frequently detected being malathion, lindane and trifluralin, in more than 60% of the subjects. Maximal levels (up to 1000-3000 ng/hands) were observed either in the general population or in workers, depending on the pesticide. However, no significant difference was observed between workers and general population handwipe pesticide levels. As expected, gardeners were exposed to pesticides sprayed in greenhouses. Florists and veterinary workers, whose pesticide exposure had not been described until now, were also indirectly exposed to pesticides used for former pest control operations. Overall, general population was exposed to more various pesticides and at levels sometimes higher than in occupational places. The most frequent pesticides in residences were not the same as in US studies but levels were similar. These preliminary results need to be confirmed in a greater number of residences from different parts of the country, in order to better assess pesticide exposure of the general population and its influencing factors.     

Heavy metal and pesticide content in commonly prescribed individual raw Chinese Herbal Medicines

Heavy metal and pesticide contamination has previously been reported in Chinese Herbal Medicines (CHMs), in some cases at potentially toxic levels. This study was conducted to determine general patterns and toxicological significance of heavy metal and pesticide contamination in a broad sample of raw CHMs. Three-hundred-thirty-four samples representing 126 species of CHMs were collected throughout China and examined for arsenic, cadmium, chromium, lead, and mercury. Of the total, 294 samples representing 112 species were also tested for 162 pesticides. At least 1 metal was detected in all 334 samples (100%) and 115 samples (34%) had detectable levels of all metals. Forty-two different pesticides were detected in 108 samples (36.7%), with 1 to 9 pesticides per sample. Contaminant levels were compared to toxicological reference values in the context of different exposure scenarios. According to a likely scenario of CHM consumption, only 3 samples (1%) with heavy metals and 14 samples (5%) with pesticides were found with concentrations that could contribute to elevated background levels of contaminant exposure. According to the most conservative scenario of CHM consumption, 231 samples (69%) with heavy metals and 81 samples (28%) with pesticides had contaminants that could contribute to elevated levels of exposure. Wild collected plants had higher contaminant levels than cultivated samples. Cadmium, chromium, lead, and chlorpyrifos contamination showed weak correlations with geographic location. Based on our assumptions of the likely mode of consumption of raw CHMs, the vast majority (95%) of the 334 samples in this study contained levels of heavy metals or pesticides that would be of negligible concern. However, given the number of samples with detectable contaminants and the range between the more likely and more conservative scenarios of contaminant exposure, more research and monitoring of heavy metals (especially cadmium and chromium) and pesticide residues (especially chlorpyrifos) in raw CHMs are advised.     

Pesticide concentrations in maternal and umbilical cord sera and their relation to birth outcomes in a population of pregnant women and newborns in New Jersey

We evaluated in utero exposures to pesticides by measuring maternal and cord serum biomarkers in a New Jersey cohort of pregnant women and the birth outcomes of their neonates. The study was based on 150 women that underwent an elective cesarean delivery at term in a hospital in central New Jersey. We evaluated the following pesticide compounds in both maternal and umbilical cord sera: chlorpyrifos, diazinon, carbofuran, chlorothalonil, dacthal, metolachlor, trifluralin and diethyl-m-toluamide (DEET). Of these compounds, chlorpyrifos, carbofuran, chlorothalonil, trifluralin, metolachlor and DEET were the pesticides most frequently detected in the serum samples. We found high (≥75th percentile) metolachlor concentrations in cord blood that were related to birth weight (3605 g in upper quartile vs 3399 g; p = 0.05). We also observed an increase in abdominal circumference with increasing cord dichloran concentrations (p = 0.031). These observations suggest that in utero exposures to certain pesticides may alter birth outcomes.     

Persistence of 12 insecticides in water

The relative importance of chemical and biological processes in the degradation of 12 insecticides in water was studied by comparing their persistence in four types of water: natural, distilled, sterilized natural and sterilized distilled. DDT, lindane and parathion dissappeared fairly quickly in the natural water, but were very persistent in the other types indicating the importance of microbial action in their degradation. There was little indication of chemical degradation of any of the organochlorine (OC) insecticides. The four compounds most stable in water were dieldrin, endrin (OCs) ethion and leptophos [organo-phosphorus (OP) insecticides]. Generally the other OP insecticides and both carbamates disappeared from all four types of water, demonstrating that chemical processes played a major role in their degradation, with biological processes having a secondary role for chlorpyrifos, diazinon and carbaryl. The observed order of persistence after 8 weeks in natural water was dieldrin > endrin > ethion > leptophos > lindane > chlorpyrifos > diazinon > mevinphos > carbofuran >p,p′-DDT > carbaryl > parathion. The random occurrence of the chemical types in this list demonstrates that generalization on persistence in the environment cannot be made on the basis of chemical structure.     

Behaviour of 12 insecticides in soil and aqueous suspensions of soil and sediment

The relative importance of chemical and biological processes in the degradation of 12 insecticides in water was studied by comparing their persistence in four types of water: natural, distilled, sterilized natural and sterilized distilled. DDT, lindane and parathion dissappeared fairly quickly in the natural water, but were very persistent in the other types indicating the importance of microbial action in their degradation. There was little indication of chemical degradation of any of the organochlorine (OC) insecticides. The four compounds most stable in water were dieldrin, endrin (OCs) ethion and leptophos [organo-phosphorus (OP) insecticides]. Generally the other OP insecticides and both carbamates disappeared from all four types of water, demonstrating that chemical processes played a major role in their degradation, with biological processes having a secondary role for chlorpyrifos, diazinon and carbaryl. The observed order of persistence after 8 weeks in natural water was dieldrin > endrin > ethion > leptophos > lindane > chlorpyrifos > diazinon > mevinphos > carbofuran >p,p′-DDT > carbaryl > parathion. The random occurrence of the chemical types in this list demonstrates that generalization on persistence in the environment cannot be made on the basis of chemical structure.     

Priority pesticides and their degradation products in river sediments from Portugal

A multiresidue gas chromatography-mass spectrometry method was developed to determine 28 priority pesticides of different chemical families (organochlorine, organophosphorus, triazines, anilides) together with some of their transformation products in river sediment. Ultrasonic, Soxhlet and pressurized liquid extraction (PLE) methods were compared in spiking experiments using acetone:hexane (1:1) followed by alumina solid phase extraction cartridges or in-cell alumina clean-up for PLE. All extraction techniques produced acceptable recoveries for the pesticides under study, although Soxhlet extraction produced the lowest recoveries for 2,4-DDE, trifluralin, lindane, and hexachlorobenzene (<50%) whereas ultrasonic extraction resulted in low recoveries for hexachlorobenzene and lindane (<50%). However, PLE using in-cell alumina clean-up produced an overestimation of more apolar compounds, given the amount of coextracted compounds. Limits of detection at the low microg L(-1)-ng L(-1) levels were obtained with Soxhlet and ultrasonic extraction, while PLE produced higher variability due to the lack of exhaustive clean-up. Given the simplicity of ultrasonic extraction, this method was further employed to determine target compounds in river sediments collected in Portugal. Lindane was detected in practically all samples, followed by trace levels of the pesticides simazine, diazinon, fenitrothion, and parathion-methyl.     

Cadmium and lead contents in rice and other cereal products in Japan in 1998-2000.

Cereals, especially rice, are a major source of cadmium (Cd) intake for general Japanese populations. In 1998-2000, rice (polished), bread (loaf), noodle and (wheat) flour samples (4113 samples in total) were collected in 63 cities all over Japan, and analyzed for Cd by inductively-coupled plasma mass spectrometry. Another pollutant element of lead (Pb) was determined in parallel. The grand geometric mean for Cd in polished raw (uncooked) rice was 50 ng/g, whereas it was 19 ng/g for flour. The value for Pb was 2-3 ng/g in rice and flour. Calculation for daily Cd intake via rice, taking advantage of the present findings on Cd contents in rice and wheat together with administrative area-specific daily consumptions of rice and wheat showed that Cd via rice is much more than Cd via wheat and that Cd via rice is highest in an area alongside the sea of Japan among the whole country, the observation being in agreement with the results from a previous food duplicate-based field survey.