Daily stream samples reveal highly complex pesticide occurrence and potential toxicity to aquatic life.

Transient, acutely toxic concentrations of pesticides in streams can go undetected by fixed-interval sampling programs. Here we compare temporal patterns in occurrence of current-use pesticides in daily composite samples to those in weekly composite and weekly discrete samples of surface water from 14 small stream sites. Samples were collected over 10-14 weeks at 7 stream sites in each of the Midwestern and Southeastern United States. Samples were analyzed for over 200 pesticides and degradates by direct aqueous injection liquid chromatography with tandem mass spectrometry. Nearly 2 and 3 times as many unique pesticides were detected in daily samples as in weekly composite and weekly discrete samples, respectively. Based on exceedances of acute-invertebrate benchmarks (AIB) and(or) a Pesticide Toxicity Index (PTI) >1, potential acute-invertebrate toxicity was predicted at 11 of 14 sites from the results for daily composite samples, but was predicted for only 3 sites from weekly composites and for no sites from weekly discrete samples. Insecticides were responsible for most of the potential invertebrate toxicity, occurred transiently, and frequently were missed by the weekly discrete and composite samples. The number of days with benthic-invertebrate PTI ≥0.1 in daily composite samples was inversely related to Ephemeroptera, Plecoptera, and Trichoptera (EPT) richness at the sites. The results of the study indicate that short-term, potentially toxic peaks in pesticides frequently are missed by weekly discrete sampling, and that such peaks may contribute to degradation of invertebrate community condition in small streams. Weekly composite samples underestimated maximum concentrations and potential acute-invertebrate toxicity, but to a lesser degree than weekly discrete samples, and provided a reasonable approximation of the 90th percentile total concentrations of herbicides, insecticides, and fungicides, suggesting that weekly composite sampling may be a compromise between assessment needs and cost.

Occupational safety training and education for needlestick injuries among nursing students in China: intervention study.

OBJECTIVES: To confirm the effect of occupational safety training and education programs (OSTEP) on needlestick injuries (NSIs) among nursing students in China. METHODS: Compare the rates and the nature of NSIs before and after OSTEP among the nursing students in China. Firstly, questionnaires were delivered to 248 randomly selected nursing students from seven training hospitals to obtain basic information concerning relevant occupational NSIs. Then regular intervention measures through OSTEP on 246 nursing students had been introduced for four years. And the resultant information concerning relevant occupational NSIs was obtained afterwards. Finally, the data analysis was performed using SPSS software, version 11.5. RESULTS: The rate of NSIs among these nursing students was relatively high before the OSTEP in China (average, 4.65 events/nurse). However, it decreased rapidly to 0.16 events/nurse average after the OSTEP. Occupational safety awareness and behavior in handling NSIs was improved in China. There was a significant difference in the results of Chi-square value (P<0.005). CONCLUSIONS: NSIs are common in nursing students in China. The OSTEP can reduce NSIs and change practical behavior markedly among nursing students in China. We should perform OSTEP on nurse students before and during the clinical practice. We must also provide effective preventive measures to reduce this kind of problem in future.

Evaluation of the permeability of agricultural films to various fumigants.

A variety of agricultural films are commercially available for managing emissions and enhancing pest control during soil fumigation. These films are manufactured using different materials and processes which can ultimately result in different permeability to fumigants. A systematic laboratory study of the permeability of the agricultural films to nine fumigants was conducted to evaluate the performance of commonly used film products, including polyethylene, metalized, and high-barrier films. The permeability, as expressed by mass transfer coefficient (cm/h), of 27 different films from 13 manufacturers ranged from below 1 × 10(-4) cm/h to above 10 cm/h at 25 °C under ambient relative humidity test conditions. The wide range in permeability of commercially available films demonstrates the need to use films which are appropriate for the fumigation application. The effects of environmental factors, such as temperature and humidity, on the film permeability were also investigated. It was found that high relative humidity could drastically increase the permeability of the high-barrier films. The permeability of some high-barrier films was increased by 2-3 orders of magnitude when the films were tested at high relative humidity. Increasing the temperature from 25 to 40 °C increased the permeability for some high-barrier films up to 10 times more than the permeability at 25 °C, although the effect was minimal for several of these films. Analysis of the distribution of the permeability of the films under ambient humidity conditions to nine fumigants indicated that the 27 films largely followed the material type, although the permeability varied considerably among the films of similar material.

Gestational atrazine exposure: effects on male reproductive development and metabolite distribution in the dam, fetus, and neonate.

Few studies have investigated the long-term effects of atrazine (ATR) following in utero exposure. We evaluated the effects of gestational exposure of Sprague Dawley dams to ATR (0, 1, 5, 20, or 100mg/kg-d) on the reproductive development of male offspring. We also quantified the distribution of ATR and its chlorinated metabolites in maternal, fetal, and neonatal fluid and tissue samples following gestational and/or lactational exposure. Dose-dependent levels of chlorotriazines, primarily diamino-s-chlorotriazine, were present in most samples analyzed, including fetal tissue. In utero exposure to 1-20mg/kg-d ATR did not alter testosterone production, the timing of puberty, play behavior, or other androgen-dependent endpoints of male offspring. Significant maternal toxicity and postnatal mortality were observed at 100mg/kg-d. We conclude that, although levels of chlorotriazines within the fetus were considerable, gestational exposures of 1-20mg/kg-d do not lead to alterations in the measures of male development examined in this study.

Development and validation of a multiresidue method for the determination of neonicotinoid and macrocyclic lactone pesticide residues in milk, fruits, and vegetables by ultra-performance liquid chromatography/MS/MS.

A multiresidue method was developed and validated for the determination of 13 neonicotinoid pesticides and metabolites, and nine macrocyclic lactone pesticides and veterinary drugs using SPE and ultra-performance liquid chromatography/MS/MS. The method was validated in milk, orange, spinach, apple, plum, watermelon, green bean, zucchini, broccoli, strawberry, grape, and tomato by analyzing replicates of residue-free control samples fortified with a mixture of 22 target analytes at three concentration levels. The recoveries of the analytes from the fortified matrixes were mostly within 70-120%, except for some of the neonicotinoid metabolites. The LOD values varied by analyte and matrix and ranged between 0.001-2 ng/g. The developed method was successful in combining two widely different classes of compounds into a single analysis.

Needlestick injuries among nursing students in China.

OBJECTIVES: To describe and characterize the rates and the nature of needlestick injuries among nursing students in China. METHODS: A questionnaire was delivered to 248 randomly selected nursing students from seven training hospitals to obtain information relevant occupational needlestick injuries. RESULTS: A total of 1144 incidents of needlestick injuries were reported among the 246 nurses during the time period of internship. The overall rate of needlestick injuries among these nurses was 100%, according to this survey. Insufficient awareness of occupational safety and limited work experience with handling needlestick injuries in these nurse students were significantly reported. In addition, when stratified by departments, the highest rate of needlestick injuries was seen in the surgery department. The occurrence of needlestick injuries is significantly related to clinical practice behaviors. CONCLUSIONS: Needlestick injuries are commonly reported in nursing students in China. Enhanced awareness of occupational safety in nursing students is expected to reduce the risk of needlestick injuries.

Source characterization using compound composition and stable carbon isotope ratio of PAHs in sediments from lakes, harbor, and shipping waterway.

Molecular compositions and compound specific stable carbon isotope ratios of polycyclic aromatic hydrocarbons (PAH) isolated from sediments were used to characterize possible sources of contamination at an urban lake, a harbor, a shipping waterway, and a relatively undisturbed remote lake in the northwest United States. Total PAH concentrations in urban lake sediments ranged from 66.0 to 16,500 microg g(-1) dry wt. with an average of 2600 microg g(-1), which is approximately 50, 100, and 400 times higher on average than PAH in harbor (48 microg g(-1) on average), shipping waterway (26 microg g(-1)), and remote lake (7 microg g(-1)) sediments, respectively. The PAH distribution patterns, methyl phenanthrene/phenanthrene ratios, and a pyrogenic index at the sites suggest a pyrogenic origin for PAHs. Source characterization using principal component analysis and various molecular indices including C2-dibenzothiophenes/C2-phenanthrenes, C3-dibenzothiophenes/C3-phenanthrenes, and C2-chrysenes/C2-phenanthrenes ratios, was able to differentiate PAH deposited in sediments from the four sites. The uniqueness of the source of the sediment PAHs from urban lake was also illustrated by compound specific stable carbon isotope analysis. It was concluded that urban lake sediments are accumulating PAH from sources that are unique from contamination detected at nearby sites in the same watershed.

Comparison of acute neurobehavioral and cholinesterase inhibitory effects of N-methylcarbamates in rat.

While the cholinesterase-inhibiting N-methyl carbamate pesticides have been widely used, there are few studies evaluating direct functional and biochemical consequences of exposure. In the present study of the acute toxicity of seven N-methyl carbamate pesticides, we evaluated the dose-response profiles of cholinesterase (ChE) inhibition in brain and erythrocytes (RBCs) as well as motor activity (both horizontally and vertically directed) and clinical signs of overt toxicity. The chemicals tested were carbaryl, carbofuran, formetanate, methiocarb, methomyl, oxamyl, and propoxur. All were administered orally, and rats were tested in 20-min activity sessions beginning 15 min after dosing; tissues were collected immediately after activity sessions. In general, motor activity was a sensitive measure of ChE inhibition for all these carbamate pesticides, and vertical activity showed the greatest magnitude of effect at the highest doses compared to either horizontal activity or ChE inhibition. Brain and RBC ChE activities were generally affected similarly. Pearson correlation coefficients of within-subject data showed good correlation between the behavioral and biochemical end points, with brain ChE inhibition and horizontal activity showing the highest correlation values. Determination of benchmark dose levels for 10% change in each end point also revealed that these two measures produced the lowest estimates. Thus, motor activity decreases are highly predictive of ChE inhibition for N-methyl carbamates, and vice versa.

Molecular and stable carbon isotopic characterization of PAH contaminants at McMurdo Station, Antarctica.

The molecular and stable carbon isotopic compositions of contaminant polycyclic aromatic hydrocarbons (PAHs) at McMurdo Station, Antarctica were analyzed in samples collected from land and sub-tidal area. PAHs in the study areas were characterized by high amounts of naphthalene and alkylated naphthalenes from petroleum products introduced by human activities in the area. Principal component analysis (PCA) of PAH composition data identified multiple sources of PAH contamination in the study area. Compositional assignments of origins were confirmed using compound specific stable carbon isotopic analysis.

Sorption of organic pollutants by marine sediments: implication for the role of particulate organic matter.

The objective of this study was to quantify sorption properties for kerogen/black carbon (BC)-bearing sediments. Single-solute sorption isotherms were measured for five pristine marine sediments using phenanthrene, naphthalene, 1,3,5-trichlorobenzene, and 1,4-dichlorobenzene as the sorbates. The results showed that the sorption isotherms were nonlinear and that the organic carbon normalized single point K(OC) values were comparable to those reported in the literature for the purified kerogen and BC, but are much higher than the data reported for HA and kerogen/BC-containing terrestrial soils and sediments. It is likely that kerogen and BC associated with these pristine marine sediments may not be encapsulated with humic acids or Fe and Mn oxides and hydroxides as often do in terrestrial soils and sediments. As a result, they may be fully accessible to sorbing molecules, exhibiting higher sorption capacities. The study suggests that competition from background HOCs and reduced accessibility when kerogen and BC are associated with terrestrial sediments may dramatically increase variability of sorption reactivities of geosorbents. Such variability may lead to large uncertainties in the prediction of sorption from the contents of kerogen and/or BC along with TOC.

Polycyclic aromatic hydrocarbon purification procedures for compound specific isotope analysis.

Purification and isotope analysis methods were developed to accurately measure the stable carbon isotope ratio of individual PAHs in environmental samples. Sample extracts were separated into several fractions by column chromatography and were purified by high-performance liquid chromatographic and thin-layer chromatographic techniques. The mean recovery of the purification method for all compounds was approximately 80%. The purity of isolates was verified by GC/MS in the full scan mode. The accuracy and precision of the method were verified using authentic standards of known isotopic compositions. The standard deviation for multiple analyses ranged between 0.1 and 0.4%o for standard material and between 0.1 and 0.7%o for environmental extracts after purification. The purification and isotope analysis methods were used to discern the sources of PAHs in environmental samples using variations in stable carbon isotopic compositions of individual compounds. Itwas confirmed thatthe purification method effectively purifies environmental samples while retaining original isotopic signatures so that PAH content and stable isotopic compositions can be used to infer contaminant sources in complex environmental settings.

Degradation of picric acid and 2,6-DNT in marine sediments and waters: the role of microbial activity and ultra-violet exposure.

Bio- and photo-transformation of two munitions and explosives of concern, 2,6-dinitrotoluene (2,6-DNT) and 2,4,6-trinitrophenol (picric acid) were assessed in spiked marine sediments and water. A sandy and a fine-grained sediment, with 0.25% and 1.1% total organic carbon, respectively, were used for biotransformation assessments at 10 and 20 degrees C. Sterilized sediments were used as controls for biotic vs. abiotic transformation. Transformation products were analyzed by HPLC, GC/MS and LC/MS. Biotransformation in sediments started soon after the initial contact of the chemicals with the sediments and proceeded for several months, with rates in the following sequence: fine-grain at 20 degrees C > fine-grain at 10 degrees C > sand at 20 degrees C > sand at 10 degrees C. The biotransformation paths seemed to be similar for all conditions. The major biotransformation product of 2,6-DNT was 2-amino-6-nitrotoluene (2-A-6-NT). 2-Nitrotoluene (2-NT) and other minor components, including N,N-dimethyl-3-nitroaniline, benzene nitrile, methylamino-2-nitrosophenol and diaminophenol, were also identified. After more prolonged incubation these chemicals were replaced by high molecular weight polymers. Several breakdown products of picric acid were identified by GC/MS, including 2,4-dinitrophenol, amino dinitrophenols, 3,4-diamino phenol, amino nitrophenol and nitro diaminophenol. Photo-transformation of 2,6-DNT and picric acid in seawater was assessed under simulated solar radiation (SSR). No significant photolysis of picric acid in seawater was observed for up to 47 days, but photo-transformation of 2,6-DNT began soon after the initial exposure to SSR, with 89% being photo-transformed in 24 h and none remaining after 72 h. High molecular weight chemicals were generated, with mass spectra ranging from molecular weight 200-500 compared to 182 for DNT, and the color of the stock solution changed from clear to orange. Complexity of the mass spectra and mass differences among fragments suggest that multiple polymers were produced and were co-eluting during the LC/MS analyses.