Earthquake hazard assessment after Mexico (1985)

The 1985 Mexican earthquake ranks foremost amongst the major earthquake disasters of the twentieth century. One of the few positive aspects of the disaster is that it provided massive quantities of data that would otherwise have been unobtainable. Every opportunity should be taken to incorporate the findings from these data in earthquake hazard assessments. The purpose of this paper is to provide a succinct summary of some of the more important lessons from Mexico. It stems from detailed field investigations, and subsequent analyses, conducted by the author on the behalf of reinsurance companies.     

Tidally driven N, P, Fe and Mn exchanges in salt marsh sediments of Tagus estuary (SW Europe)

Short-sediment cores and flooding water were collected at 0, 5, 15, 25 and 50?min of tidal inundation in the two sites colonised by pure stands of Spartina maritima (low marsh) and Sarcocornia fruticosa (high marsh) from the Rosário salt marsh (Tagus estuary, SW Europe). Concentrations of NH (4) (+) , NO (3) (-) +?NO (2) (-) and HPO (4) (2-) , Fe and Mn were measured in tidal flooding water and pore water. Flooding water is enriched in nutrients, particularly ammonium due to local discharge of untreated urban effluents. Nevertheless, NH (4) (+) and NO (3) (-) +?NO (2) (-) concentrations in flooding waters at t?=?5?min (NH (4) (+) =?246?±?7?μM, NO (3) (-) +?NO (2) (-) =?138?±?1?μM for S. fruticosa and NH (4) (+) =?256?±?8?μM, NO (3) (-) +?NO (2) (-) =?138?±?1?μM for S. maritima) rose sharply at both vegetated sites. An increase was also registered for HPO (4) (2-) and total dissolved Fe although the subsequent decrease was smoother. Advective transport induced by the two daily pulses of inundation is several orders of magnitude higher than the diffusive fluxes during submerged periods. In addition, solutes are exported from the sediment with the inundation and imported in submerged periods. The exported amount of inorganic nitrogen during tidal inundation (export of 3,200?μmol?N?m(-2)?day(-1)to the water column), is not counterbalanced by the sink of -290?μmol?N?m(-2)?day(-1) occurred during the submerged period.     

The efficacy of protoporphyrin as a predictive biomarker for lead exposure in canvasback ducks: Effect of sample storage time

We used 363 blood samples collected from wild canvasback dueks (Aythya valisineria) at Catahoula Lake, Louisiana, U.S.A. to evaluate the effect of sample storage time on the efficacy of erythrocytic protoporphyrin as an indicator of lead exposure. The protoporphyrin concentration of each sample was determined by hematofluorometry within 5 min of blood collection and after refrigeration at 4 °C for 24 and 48 h. All samples were analyzed for lead by atomic absorption spectrophotometry. Based on a blood lead concentration of 0.2 ppm wet weight as positive evidence for lead exposure, the protoporphyrin technique resulted in overall error rates of 29%, 20%, and 19% and false negative error rates of 47%, 29% and 25% when hematofluorometric determinations were made on blood at 5 min, 24 h, and 48 h, respectively. False positive error rates were less than 10% for all three measurement times. The accuracy of the 24-h erythrocytic protoporphyrin classification of blood samples as positive or negative for lead exposure was significantly greater than the 5-min classification, but no improvement in accuracy was gained when samples were tested at 48 h. The false negative errors were probably due, at least in part, to the lag time between lead exposure and the increase of blood protoporphyrin concentrations. False negatives resulted in an underestimation of the true number of canvasbacks exposed to lead, indicating that hematofluorometry provides a conservative estimate of lead exposure.The U.S. Government's right to retain a non-exclusive, royalty-free licence in and to any copyright is acknowledgedDeceased     

Soil properties and crop productivity as influenced by flyash incorporation in soil

Field experiments were carried out during 1996–97at Gulawathi, Muthiani and Salarpur Villages, IARI Farm, NewDelhi and NCPP Campus, Dadri to evaluate changes in soilcharacteristics and growth of wheat (Triticum aestivum L.),mustard (Brassica juncea L.), lentil (Lence esculentaMoench.), rice (Oryza sativa L.) and maize (Zea mays L.) byvarying amounts of flyash addition (up to 50t ha^-1) in soils atsowing/transplanting time of crops. Flyash addition in areasadjoining NCPP Thermal Power Plant, Dadri, Ghaziabad, U.P.ranged from 5–12 t ha^-1 yr^-1 in 1995–96. Shoot and root growthand yield of test crops at different locations after flyashincorporation resulted in beneficial effects of flyashaddition in most cases. The silt dominant texture of flyashimproved loamy sand to sandy loam textures of the surfacesoils at the farmers' fields. The increased growth in yield ofcrops with flyash incorporation was possibly due tomodifications in soil moisture retention and transmissioncharacteristics, bulk density, physico-chemical characterssuch as pH and EC and organic carbon content. The response offlyash addition in the soil on soil health and cropproductivity needs to be evaluated on long-term sustainableaspects.     

Presence of Torque Teno Virus (TTV) in Tap Water in Public Schools from Southern Brazil

Torque teno virus (TTV) was surveyed in tap water collected in schools from three municipalities located in the south of Brazil. TTV genomes were found in 11.7 % (4/34) of the samples. TTV DNA was detected in 10.5 % (2/19) of the samples collected at the city of Caxias do Sul and in 25 % (2/8) of the samples from Pelotas. Those cities have a low rate of sewage treatment. All samples from Santa Cruz do Sul, which has nearly 92 % of its sewage treated, were negative. These results suggest that the amount of sewage treated may have an effect on the detection rates of TTV DNA in drinking water in a given urban area, showing a mild negative correlation (r = ?0.76), when comparing the percentage of sewage treatment to the detection of TTV genomes. The detection rate of TTV was also compared with Escherichia coli, showing a strong correlation (r = 0.97), indicating that TTV may be a suitable marker of fecal contamination.     

The cerebro-hepato-renal (Zellweger) syndrome: Prenatal detection based on impaired biosynthesis of plasmalogens

Prenatal diagnosis of the cerebro-hepato-renal (Zellweger) syndrome has been performed in 10 pregnancies at risk by measuring both the activity of acyl CoA: dihydroxyacetonephosphate acyltransferase (DHAP-AT) and the de novo plasmalogen biosynthesis, either in cultured amniotic fluid cells or in fibroblasts cultured from a chorionic villus biopsy. In 7 of the pregnancies both tests indicated no abnormality. All 7 continued to term and normal infants were delivered. However, in amniotic fluid cells from 2 fetuses affected by Zellweger syndrome unequivocal differences from control values were found. The activity of DHAP-AT was clearly deficient and the de novo plasmalogen biosynthesis was impaired. In one pregnancy at risk prenatal diagnosis was performed during the first trimester by measuring both the DHAP-AT activity and the de novo plasmalogen biosynthesis in fibroblasts cultured from a chorionic villi biopsy. From the deficient DHAP-AT activity and the impaired de novo plasmalogen biosynthesis it was concluded that the fetus was affected. This was confirmed biochemically after induced abortion. It can be concluded that measurement of the DHAP-AT activity and the de novo plasmalogen biosynthesis provides convenient methods for the early prenatal detection of Zellweger syndrome.     

Adsorption and movement of carbaryl in soils: A verification of cosolvent theory and comparison of batch equilibrium and soil thin layer chromatography results

Batch equilibrium and soil thin layer chromatography (TLC) techniques were used to investigate the influence of different volume fractions of organic cosolvents (acetone and methanol) on the adsorption and movement of carbaryl in four different types of Indian soils. L-shaped isotherms were obtained for both the cosolvent–water mixtures at all f _s values and were in close agreement with the Freundlich equation. Higher adsorption was observed on F.R.I. soil (FSL) followed by Alampur soil (ASL), Kalai soil (KL), and Bhoran soil (BSL) at all f _s values for both the cosolvent systems as was anticipated from the K and K _D values. The K and K _D values also confirmed that carbaryl adsorption was higher in methanol–water mixture than acetone–water mixture and decreased with increasing f _s values. The frontal R _f values obtained from soil TLC studies were inversely proportional to the K and K _D values for both the cosolvent systems. The higher K and K _D values and lower R _f values in methanol–water mixtures relative to acetone–water mixtures for all the soils indicated that acetone had a greater potential for ground water contamination compared to methanol. The adsorption data were used to evaluate the cosolvent theory for describing adsorption of carbaryl in acetone–water and methanol–water mixtures. The aqueous phase partition coefficients, K _DW (mol g^?1), normalized with respect to f _oc for carbaryl was evaluated by extrapolating f _s → 0.