Trihalomethane Formation Potential and Concentration Changes During Water Treatment at Mumbai (India)

The treated water at the outlet oftreatment plants and representative servicereservoirs of Mumbai city have been evaluatedfor trihalomethane formation potential in1995–1996. Chloroform, dichlorobromomethane,chlorodibromomethane and bromoform have beenmonitored during monsoon, winter and summer.The levels of chloroform are found above theregulated WHO guideline value of 200 g L^-1 in final water during postmonsoon atGhatkopar (226 g L^-1), Malbar (210.3 g L^-1) and Tulsi (231.26 g L^-1).     

Trends of organochlorine pesticides in drinking water supplies

The effectiveness of the treatment process for the removal of pesticides in the final water supplies in Delhi has been evaluated. Samples were collected during 2000–2005 from five water treatment plants (WTPs). Analysis was carried out to identify pesticides, which are more commonly encountered in treated drinking water. In most of the treatment plants, the concentrations of lindane, total endosulphan and total DDT were significantly less in the finished water. Monitoring of these less soluble pesticide in the finished water from WTPs was done quarterly to arrive at the quality trends and to plan for the mitigation action, in case the concentration of the parameter exceeded at any site or time.     

Relating dissolved organic matter fluorescence and functional properties

The fluorescence excitation–emission matrix properties of 25 dissolved organic matter samples from three rivers and one lake are analysed. All sites are sampled in duplicate, and the 25 samples include ten taken from the lake site, and nine from one of the rivers, to cover variations in dissolved organic matter composition due to season and river flow. Fluorescence properties are compared to the functional properties of the dissolved organic matter; the functional assays provide quantitative information on photochemical fading, buffering capacity, copper binding, benzo[a]pyrene binding, hydrophilicity and adsorption to alumina. Optical (absorbance and fluorescence) characterization of the dissolved organic matter samples demonstrates that (1) peak C (excitation 300–350 nm; emission 400–460 nm) fluorescence emission wavelength; (2) the ratio of peak T (excitation 220–235 nm; emission 330–370 nm) to peak C fluorescence intensity; and (3) the peak C fluorescence intensity: absorbance at 340 nm ratio have strong correlations with many of the functional assays. Strongest correlations are with benzo[a]pyrene binding, alumina adsorption, hydrophilicity and buffering capacity, and in many cases linear regression equations with a correlation coefficient >0.8 are obtained. These optical properties are independent of freshwater dissolved organic carbon concentration (for concentrations <10 mg L⁻¹) and therefore hold the potential for laboratory, field and on-line monitoring and prediction of organic matter functional properties.     

Identification of the cellular site of polychlorinated peptide biosynthesis in the marine sponge Dysidea (Lamellodysidea) herbacea and symbiotic cyanobacterium Oscillatoria spongeliae by CARD-FISH analysis

Populations of the sponge Dysidea (Lamellodysidea) herbacea, which host the cyanobacterium Oscillatoria spongeliae, vary in their production of polychlorinated peptides. Peptide natural products previously isolated from D. herbacea are often halogenated and include dysidin, dysidinin, and a series of chlorinated diketopiperazines. Strikingly, the distinctive leucine-derived trichloromethyl signature of these compounds is shared only with metabolites of the marine cyanobacterium Lyngbya majuscula, and includes such compounds as barbamide and nordysidinin. Genetic information available for the barbamide biosynthetic gene cluster was used to successfully polymerase chain reaction (PCR) amplify a barB1 homolog (dysB1) from D. herbacea samples collected in Papua New Guinea. Catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH) analysis showed that dysB1 oligonucleotide probes hybridized to sequences in the filamentous cyanobacterial symbiont O. spongeliae. Consistent with this finding, a D. herbacea/O. spongeliae collection devoid of the polychlorinated peptides did not contain the barB1 homologs.Communicated by P.W. Sammarco, Chauvin     

Hydrogen Peroxide and Ultraviolet Irradiations in Water Treatment

Trihalomethanes (THMs) the by-products of chlorination in water treatment are recognised as a threat to public health due to their carcinogenicity. The photodegradation of THMs using hydrogen peroxide has been found to give increased removal efficiency and the outcome of the study may find, its application in designing a unit process for water treatment. Batch experiments were carried out using UV lamp of 83 W and 40% w/w Hydrogen peroxide (H₂O₂) in test waters between 2.5–10 pH range of chloroform, bromodichloromethane, dibromochloromethane and bromoform at 50–200 μg L⁻¹ initial concentration. 92–100% removal of chloroform, bromodichloromethane, dibromochloromethane and bromoform were found with 0.1% of H₂O₂ and 90 min of UV exposure.     

Removal technology for pesticide contaminants in potable water

Abstract

Granular activated carbon adsorption is one of the reliable and effective means of removing organochlorine pesticides from water. Continuous stirred tank and fix bed reactor systems were used for the screening of indigenous granular activated carbons in the removal of organochlorine pesticides from water at low microgram levels in simulated samples. The carbon dose reguired to treat raw water at initial concentrations of 5–10 ug/1 of Y‐HCH, p,p'‐DDT and p,p'‐DDE to <2 ug/1 potable level was computed. Data leads to the development of a tap attachable water treatment unit for pesticides removal for applications on domestic scale.     

The effects of drop size and formulation upon the spread of pesticide droplets impacting on water‐sensitive papers

Abstract

The effects of drop size and formulation upon the spread of pesticide droplets impacting on water‐sensitive papers (WSPs) was investigated. Droplets of diameter 70–350 μm, of four permethrin formulations, were produced using a monosize droplet generator. The droplets were collected on WSPs and in Dow Corning fluid and their diameters measured using a binocular microscope. Spread factors, upon the WSPs, for each dropsize/formulation combination were then calculated. Spread factors varied with both formulation and droplet size and for droplets of 200 and 300 μm diameter spread was significantly correlated with the dynamic surface tension of the formulation. The results suggest that proper calibration of WSPs is necessary for effective droplet sizing.     

Phosphorus composition of manure from swine fed low-phytate grains: evidence for hydrolysis in the animal

Including low-phytic-acid grains in swine diets can reduce P concentrations in manure, but the influence on manure P composition is relatively unknown. To address this we analyzed manure from swine fed one of four barley (Hordeum vulgare L.) varieties. The barley types consisted of wild-type barley (CDC bold, normal barley diet) and three low-phytic-acid mutant barleys that contained similar amounts of total P but less phytic acid. The phytic acid concentrations in the mutant barleys were reduced by 32% (M422), 59% (M635), and 97% (M955) compared with that in the wild-type barley, respectively. Phosphorus concentrations were approximately one-third less in manures from animals fed low-phytic-acid barleys compared with those fed the wild-type variety. Phytic acid constituted up to 55% of the P in feed, but only trace concentrations were detected in NaOH-EDTA extracts of all manures by solution (31)P nuclear magnetic resonance (NMR) spectroscopy. Phosphate was the major P fraction in the manures (86-94% extracted P), with small concentrations of pyrophosphate and simple phosphate monoesters also present. The latter originated mainly from the hydrolysis of phospholipids during extraction and analysis. These results suggest that phytic acid is hydrolyzed in swine, possibly in the hind gut by intestinal microflora before being excreted in feces, even though the animals have little phytase activity in the gut and derive little nutritional benefit from phytate P. We conclude that feeding low-phytic-acid grains reduces total manure P concentrations and the manure P is no more soluble than P generated from normal barley diets.     

Association of color and feeding deterrence by tropical reef fishes

Summary. While many marine molluscs have been suggested to use aposematic coloration to avoid predation, few studies have tested the ability of marine predators to learn to associate colors with distasteful prey. In field experiments, we tested the ability of two populations of reef fishes to discriminate among red, yellow, and black artificial nudibranch models when one color was paired with a feeding deterrent. We offered fishes (1) the models without any feeding deterrents, (2) the models with a feeding deterrent coated onto one color, and (3) the models without deterrents again. If reef fishes learn to associate colors with noxious prey, we expected the color paired with the feeding deterrent to be eaten less frequently in the final assay than the initial assay. In both populations, fishes formed clear associations between color and feeding deterrence. However, when the experiment was repeated in one population, changing the color paired with the feeding deterrent, fishes did not form an association between color and feeding deterrence. In this case, prior learning may have affected subsequent trials. Our study indicates that common colors of nudibranchs are recognizable by fishes and can be associated with noxious prey. Received 24 September 1998; accepted 18 December 1998.