Search Results - (Author, Cooperation:R. M. Harrison)

2013-12-07

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

1747-6593

Blackwell Publishing Journal Backfiles 1879-2005

Energy, Environment Protection, Nuclear Power Engineering

This paper presents data on the distribution of seven pesticides in an agricultural catchment which is located within the Agricultural Development and Advisory Service farm at Rosemaund, 11 km north-east of Hereford, UK. Data for aldicarb, atrazine, carbofuran, dimethoate, MCPA and isoproturon, are available for both the soil and surface waters (drain and stream water), with simazine data available only for the stream. Measurements were taken before and after pesticide application, which was made following normal agricultural practice. Soil residue data showed the degradation rates of the pesticides to be within the range of literature values. Pesticide levels in the stream and drains during runoff events following rainfall ranged from below detection limits (typically 0.02-0.1 μg/1), to 264 μg/1 (for carbofuran). Over 90% of the events had detectable maximum concentrations. The percentage of pesticide applied, which was removed during individual rainfall events, was calculated. The maximum value estimated was 1.1%, again for carbofuran. Most of the events gave values several orders of magnitude below this value.The data have been used to try to validate a range of models which could be used for screening new pesticides or for informing decisions on the use of existing pesticides. The results of the validations are summarized.

Electronic Resource

1747-6593

Blackwell Publishing Journal Backfiles 1879-2005

Energy, Environment Protection, Nuclear Power Engineering

Data are presented on four pesticides applied to agricultural land at the Agricultural Development Advisory Service, Rosemaund, in the west of England. The farm covers a well-defined and isolated water basin of cracking heavy clay loam soils drained by a single stream. Levels of the relatively particle-bound pesticides trifluralin, deltamethrin, chlorpyrifos and fenpropimorph were measured in drainage water and field soils following application. Observed concentrations in water were generally below 1 μg/l with occasional peak levels exceeding 10 μg/l during storm rainfall events. Unexpectedly high peak levels of deltamethrin of around 2 μg/l highlighted significant bypass flow mechanisms from the surface soils during the autumn. Additional bioassay experiments showed that levels of chlorpyrifos, lethal to Gammarus pulex, reached the stream during spring 1993. The Rosemaund farm has been the site of a continuing investigation into the movement of agricultural pesticides to surface waters since 1987, and this report represents the final work conducted in the autumn of 1992 and spring 1993.

Electronic Resource

1420-9071

Springer Online Journal Archives 1860-2000

Biology

Medicine

Summary Cadmium is present naturally in the air mainly as a result of volcanic emissions and release by vegetation. Anthropogenic sources, which overall give rise to emissions one order of magnitude greater than natural sources, are largely primary non-ferrous metals production and waste incineration. Measured concentrations of airborne cadmium are typically 〈 1 ng m−3 at remote sites, 0.1–10 ng m−3 at rural sites and 1–100 ng m−3 at urban and industrial sites, dependent upon the nature and proximity of local sources. Particle sizes are generally 〈2 μm, and often considerably smaller, consistent with an anthropogenic source and a long atmospheric life-time. Cadmium deposition to the land occurs with fluxes varying from 0.05 ng cm−2 month−1 in Greenland to circa 1000 ng cm−2 month−1 in the vicinity of major industrial sources. The possible significance of a motor vehicular source of airborne cadmium is also reviewed.

Electronic Resource

1573-0662

Heterogeneous reaction ; N2O5 ; annular reactor ; reaction probability

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Geosciences

Abstract A method for the estimation of the reaction probability of the heterogeneous N2O5+H2O → 2HNO3 reaction using the deposition profile in a laminar flow tube, in which the walls are coated with the condensed aqueous phase of interest, is presented. The production of gas phase nitric acid on the surface followed by its absorption complicates the deposition profiles and hence the calculation of the reaction probability. An estimation of the branching ratio for this process enables a more appropriate calculation to be carried out. Reaction probabilities of N2O5 on substances including some normally constituting atmospheric aerosols, NaCl, NH4HSO4, as well as Na2CO3 are estimated and found to depend on relative humidity and characteristics of the coating used. These fell within the range (0.04–2.0)×10−2.

Electronic Resource

1573-0662

hydroxyl radical ; troposphere ; modelling ; steady state

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Geosciences

Abstract Calculated and observed hydroxyl (OH) fields are presented. Calculated OH was obtained in three ways using (1) a photochemical box-model (2) a simple OH steady state approach and (3) a variant on (2) – the ‘multiple equation steady state’ approach which assumes steady state for OH, HO2 and RO2 and hence obtains three simultaneous, non linear, equations. All three methods used data collected in June 1995 during the Weybourne Atmospheric Observatory Summer Experiment (WAOSE'95). Julian Days 169, 178, 179 and 180 displayed especially good data capture and were consequently chosen for study. The two steady state methods are essentially driven purely by observations and derive OH from the ratio of the relevant source and sink terms. The box-model was constrained where possible to observations; remaining unmeasured volatile organic compounds (VOCs) were initialised to an arbitrary low value of 10 ppt. Agreement between theory and experiment was usually around 50% and often better than this value, especially on J169, though discrepancies of up to a factor of 3 were occasionally apparent. Despite the inherent scatter, neither the box-model nor the simple steady state method were found to consistently over-estimate OH (a common feature of many numerical approaches) although this did occur to a certain extent using the multiple equation steady state approach, probably due to breakdowns in the steady state approximation. More data spread was evident in the box-model approach compared with the other methods. An analysis of the major sources and sinks of OH is presented for the three methods of calculation. Calculated and observed peroxy radicals are also presented. Calculated peroxy radicals were generally lower than that observed at night yet higher, sometimes by up to a factor of 7, during the day. Possible explanations for this result are explored.

Electronic Resource

0003-276X

Life and Medical Sciences ; Cell & Developmental Biology

Wiley InterScience Backfile Collection 1832-2000

Medicine

Studies were undertaken to assess the fine structural effects of vasectomy upon the rhesus monkey testis, using 27 monkeys subjected to one of three surgical techniques: control sham operation (COS), unilateral silk vasoligation (USV), or unilateral clasp vaso-occlusion (UCV). The monkeys were sacrificed from 1 to 66 weeks after surgery; tissues were fixed in glutaral-dehyde in collidine buffer and processed for electron microscopy (EM) using routine techniques. No alterations were noted in the seminiferous epithelium of any COS animal; only focal lesions were found in vasectomized animals. These changes correlated with length of time post-vasectomy, a finding consistent with earlier light microscopic studies (Heidger et al., '78). Even at the longest post-operative periods studied, spermatogenesis appeared in most animals to be normal. One animal exhibited areas in which the seminiferous epithelium consisted of Sertoli cells and spermatogonia, only. The seminiferous epithelium of approximately one-third of other animals, both on the vasectomized and contra-lateral sides, exhibited such alterations as development of extensive infoldings and duplication within the basal lamina, and presence within the basal Sertoli cell cytoplasm of late spermatids and sperm tails. These alterations were observed in both UCV and USV animals. The presence of such late germ cells in the basal Sertoli cell cytoplasm was noted by light microscopy; however, lu-minal spermiophages encountered in one animal at the light microscopic level were not detected in our EM study, which underscores the limitations of EM as a survey technique. All UCV animals developed spermatic granulomas of the vas, whereas only 3 of 13 USV animals developed such granulomas. It does not appear that the alterations exhibited by the animals in this study would necessarily dispose toward impaired spermatogenesis following vasovasostomy.

Electronic Resource

0268-2605

Trimethyl-lead ; interlaboratory study ; analytical performance ; quality control ; simulated rainwater ; urban dust ; Chemistry ; Organic Chemistry

Wiley InterScience Backfile Collection 1832-2000

Chemistry and Pharmacology

An interlaboratory programme has been started within the Measurements and Testing Programme (formerly BCR) of the European Commission to evaluate the performance of analytical techniques used for the determination of trimethyl-lead in simulated rainwater and urban dust. A first interlaboratory study on solutions was successfully concluded in 1993 and a second exercise was organized, focusing on simulated rainwater and urban dust analysis. This paper reports the results of this second interlaboratory study, which is a preparatory step for a certification campaign of simulated rainwater (with representative contamination levels) and urban dust.

4 Ill.

Electronic Resource

0268-2605

trimethyllead ; interlaboratory study ; quality control ; simulated rainwater ; Chemistry ; Organic Chemistry

Wiley InterScience Backfile Collection 1832-2000

Chemistry and Pharmacology

Determinations of the trimethyllead moiety in environmental samples are carried out by a number of laboratories in Europe. To verify the quality of such determinations, the Measurements and Testing Programme (formerly BCR) of the European Commission organised an interlaboratory exercise which allowed discussion and comparison of the different techniques used so far in lead speciation analyses. In addition, this first step enabled a study of the feasibility of the preparation of candidate reference materials (CRMs) for the determination of the trimethyllead moiety in simulated rainwater to be carried out. The solutions used in this study were carefully prepared and their homogeneity and stability verified. This paper describes the organisation and the results of the intercomparison and discusses the further development of the project.

1 Ill.

Electronic Resource