Effects of a sulfonylurea herbicide on the soil bacterial community

Sulfonylurea herbicides are widely used on a wide range of crops to control weeds. Chevalier® OnePass herbicide is a sulfonylurea herbicide intensively used on cereal crops in Algeria. No information is yet available about the biodegradation of this herbicide or about its effect on the bacterial community of the soil. In this study, we collected an untreated soil sample, and another sample was collected 1 month after treatment with the herbicide. Using a high-resolution melting DNA technique, we have shown that treatment with Chevalier® OnePass herbicide only slightly changed the composition of the whole bacterial community. Two hundred fifty-nine macroscopically different clones were isolated from the untreated and treated soil under both aerobic and microaerobic conditions. The strains were identified by sequencing a conserved fragment of the 16S rRNA gene. The phylogenetic trees constructed using the sequencing results confirmed that the bacterial populations were similar in the two soil samples. Species belonging to the Lysinibacillus, Bacillus, Pseudomonas, and Paenibacillus genera were the most abundant species found. Surprisingly, we found that among ten strains isolated from the treated soil, only six were resistant to the herbicide. Furthermore, bacterial overlay experiments showed that only one resistant strain (related to Stenotrophomonas maltophilia) allowed all the sensitive strains tested to grow in the presence of the herbicide. The other resistant strains allowed only certain sensitive strains to grow. On the basis of these results, we propose that there must be several biodegradation pathways for this sulfonylurea herbicide.     

Recovery of benthic invertebrate communities from acidification in Killarney Park lakes

Using a reference-condition comparison, recovery of benthic invertebrate communities from acidification was assessed in three lakes in Killarney Wilderness Park approximately 40–60 km from the massive metal smelters in Sudbury, Canada. Test site analyses (TSAs) were used to compare the park lakes to 20 reference lakes near Dorset Ontario, 200 km to the east. An extension of a previous survey (1997–2001) of two sensitive mayfly species (Stenonema femoratum and Stenacron interpunctatum) was conducted in one of the lakes. TSA results indicate that the three Killarney lakes remain significantly different from reference condition due primarily to higher abundances of a few acid-tolerant families and the presence of some less abundant sensitive families. Colonization rates differ greatly between the two mayfly species presumably because of competition for available habitat. Overall, this study suggests that early colonizers will gain an advantage to out-compete subsequent arrivals, and these competitive interactions will delay the return of communities to reference condition.     

McKusik-Kaufman syndrome: prenatal diagnosis,genetics and follow up

McKusick-Kaufman syndrome (MKKS) is a rare autosomal recessive genetic disease with classical hexadactyly and hydrocolpos in females and sometimes cardiac abnormality. We report such a case diagnosed just before birth with a favourable outcome. From this case we describe and discuss all the prenatal sonographic signs which are not always present. On the genetic side, the gene has recently been localized together with the mutation responsible for MKKS. The phenotypic relationship between MKKS which has a good prognosis and Bardet-Biedl syndrome (BBS) with a worse prognosis requires great caution before diagnosing MKKS and a long follow-up is necessary to recognize obesity, growth retardation and pigmentary retinitis. Copyright © 2002 John Wiley & Sons, Ltd.     

Climate Change Impact on Riverine Nutrient Load and Land-Based Remedial Measures of the Baltic Sea Action Plan

To reduce eutrophication of the Baltic Sea, all nine surrounding countries have agreed upon reduction targets in the HELCOM Baltic Sea Action Plan (BSAP). Yet, monitoring sites and model concepts for decision support are few. To provide one more tool for analysis of water and nutrient fluxes in the Baltic Sea basin, the HYPE model has been applied to the region (called Balt-HYPE). It was used here for experimenting with land-based remedial measures and future climate projections to quantify the impacts of these on water and nutrient loads to the sea. The results suggest that there is a possibility to reach the BSAP nutrient reduction targets by 2100, and that climate change may both aggravate and help in some aspects. Uncertainties in the model results are large, mainly due to the spread of the climate model projections, but also due to the hydrological model.     

A simple empirical model to predict forest insecticide ground-level deposition from a compendium of field data

Deposit data from 205 aerial forest insecticide applications conducted in field trials by the Canadian Forest Service, Great Lakes Forestry Centre over a 15-year period are summarized. Deposit measurements were taken under "worst case" scenarios in the sense that direct applications were made over water bodies, and ground samplers were intentionally placed in open or cleared areas of forest. The median % deposit on shoreline collectors (32 separate applications) was 5.7%, on mid-stream collectors (44 separate applications) was 6.2%, and on forest floor collectors (129 separate applications) was 4.9%. Forest floor deposit was most closely associated with application rate and droplet size (r = 0.624, p < 0.001 and r = 0.662, p = 0.011, respectively) but these variables combined only explained 44% of the variation in deposit. Data from all three collector types were grouped by 10% deposit increments and combined to provide a data set from all deposition scenarios. A negative exponential model was fitted to the proportion of these combined sites regressed on % deposit in 10% increments and plotted as a deposit probability distribution curve (p < 0.001, r2 = 0.992). The probability distribution curve indicated that 5-10% deposit would be expected about 57-91% of the time, whereas 50% deposit or greater would be expected about 2% of the time or less. In a probabilistic risk assessment for aerially applied insecticides in a conifer-dominated forest environment, the probability distribution curve based on empirical data presented here can be used to refine the characterization of exposure scenarios from which effects estimates can be derived.     

Driver and front passenger injury in frontal crashes: Update on the effect of unbelted rear occupants

Purpose: This is a study of the influence of an unbelted rear occupant on the risk of severe injury to the front seat occupant ahead of them in frontal crashes. It provides an update to earlier studies.

Methods: 1997–2015 NASS-CDS data were used to investigate the risk for severe injury (Maximum Abbreviated Injury Score [MAIS] 4+F) to belted drivers and front passengers in frontal crashes by the presence of a belted or unbelted passenger seated directly behind them or without a rear passenger. Frontal crashes were identified with GAD1 = F without rollover (rollover ≤ 0). Front and rear outboard occupants were included without ejection (ejection = 0). Injury severity was defined by MAIS and fatality (F) by TREATMNT = 1 or INJSEV = 4. Weighted data were determined. The risk for MAIS 4+F was determined using the number of occupants with known injury status MAIS 0+F. Standard errors were determined.

Results: The risk for severe injury was 0.803 ± 0.263% for the driver with an unbelted left rear occupant and 0.100 ± 0.039% with a belted left rear occupant. The driver's risk was thus 8.01 times greater with an unbelted rear occupant than with a belted occupant (P <.001). With an unbelted right rear occupant behind the front passenger, the risk for severe injury was 0.277 ± 0.091% for the front passenger. The corresponding risk was 0.165 ± 0.075% when the right rear occupant was belted. The front passenger's risk was 1.68 times greater with an unbelted rear occupant behind them than a belted occupant (P <.001). The driver's risk for MAIS 4+F was highest when their seat was deformed forward. The risk was 9.94 times greater with an unbelted rear occupant than with a belted rear occupant when the driver's seat deformed forward. It was 13.4 ± 12.2% with an unbelted occupant behind them and 1.35 ± 0.95% with a belted occupant behind them.

Conclusions: Consistent with prior literature, seat belt use by a rear occupant significantly lowered the risk for severe injury to belted occupants seated in front of them. The reduction was greater for drivers than for front passengers. It was 87.5% for the driver and 40.6% for the front passenger. These results emphasize the need for belt reminders in all seating positions.     

Ecological risk assessment of pesticide residues in coastal lagoons of Nicaragua

A detailed investigation on the contamination with chlorinated hydrocarbons and organophosphorous pesticides of the coastal lagoon system of Chinandega district, Nicaragua, allowed the identification of contaminant sources and lagoon areas currently more contaminated. The discharge of rivers into the lagoons is the main transport pathway of pesticide residues; whereas atmospheric depositions are likely to be the main pathway for the introduction of PCBs into the lagoons. Analysis of water samples indicates widespread contamination with soluble organophosphorous compounds, such as dichlorvos, up to 410 ng L(-1), diazinon, up to 150 ng L(-1), and chlorpyrifos, up to 83 ng L(-1). Analyses of suspended matter for low solubility organochlorine (OC) compounds revealed very high concentrations of toxaphene, up to 17,450 ng g(-1) dry weight (dw), total DDTs up to 478 ng g(-1), Aroclor 1254, up to 119 ng g(-1) (dw), and lower concentrations for other compounds. Lagoon sediments contain high concentrations also of toxaphene, from 7.9 to 6,900 ng g(-1) (dw), and DDTs, from 1.5 to 321 ng g(-1) (dw), and lower concentrations of chlorpyrifos, hexachlorocyclohexanes, chlordane and other residues. Concentrations of OCs in soft tissues of clams are statistically correlated with the concentrations of the same compounds in bottom sediments, indicating that sediments are a source of contaminants to biota. In some areas of the lagoon system, concentration of residues in sediments are far above recommended threshold guideline values for protection of aquatic life, and may cause acute and chronic toxic effects on more sensitive aquatic species. Despite the ban on the use of toxaphene and DDT, residues of these compounds are still entering the lagoons due to erosion of, and leaching from, agriculture soils in the region. Measures for protection of the lagoon ecosystem are discussed.     

Bioremediation of Stranded Oil on an Arctic Shoreline

The application of slow-release and soluble fertilizers proved to be an effective and environmentally benign way of stimulating oil biodegradation on an Arctic shoreline. Fertilizer application to the surface of the beach delivered nutrients to the oiled sediment beneath the beach surface. There was no significant run-off of this fertilizer to either the nearshore water or to unfertilized plots, and there were no adverse toxicological effects of the fertilizer application. The fertilizer application was followed by an increase in oxygen consumption and carbon dioxide evolution from the beach, increased microbial biomass, and significantly greater biodegradation of oil on the plots that had received fertilizer. The rate of oil biodegradation was approximately doubled over the course of a year by fertilizer applications in the first two months after the spill.Simple test kits proved adequate to monitor the fertilizer-application process in the field in a time frame that would allow the application process to be fine-tuned during treatment on a real spill. Simple test kits and portable instrumentation were useful in demonstrating the initial success of the bioremediation strategy.     

Misspecification of within-area exposure distribution in ecological Poisson models

Ecological studies enable investigation of geographic variations in exposure to environmental variables, across groups, in relation to health outcomes measured on a geographic scale. Such studies are subject to ecological biases, including pure specification bias which arises when a nonlinear individual exposure-risk model is assumed to apply at the area level. Introduction of the within-area variance of exposure should induce a marked reduction in this source of ecological bias. Assuming several measurements per area of exposure and no confounding risk factors, we study the model including the within-area exposure variability when Gaussian within-area exposure distribution is assumed. The robustness is assessed when the within-area exposure distribution is misspecified. Two underlying exposure distributions are studied: the Gamma distribution and an unimodal mixture of two Gaussian distributions. In case of strong ecological association, this model can reduce the bias and improve the precision of the individual parameter estimates when the within-area exposure means and variances are correlated. These different models are applied to analyze the ecological association between radon concentration and childhood acute leukemia in France.