Anthropogenic activities associated with industrialization, agriculture and urbanization have led to the deterioration in water quality due to various contaminants. To assess the status of urban drinking water quality, samples were collected from the piped supplies as well as groundwater sources from different localities of residential, commercial and industrial areas of Lucknow City in a tropical zone of India during pre-monsoon for estimation of coliform and faecal coliform bacteria, organochlorine pesticides (OCPs) and heavy metals. Bacterial contamination was found to be more in the samples from commercial areas than residential and industrial areas. OCPs like α,γ-hexachlorocyclohexane and 1,1 p,p-DDE {dichloro-2, 2-bis(p-chlorophenyl) ethene)} were found to be present in most of the samples from study area. The total organochlorine pesticide levels were found to be within the European Union limit (0.5 μg/L) in most of the samples. Most of the heavy metals estimated in the samples were also found to be within the permissible limits as prescribed by World Health Organization for drinking water. Thus, these observations show that contamination of drinking water in urban areas may be mainly due to municipal, industrial and agricultural activities along with improper disposal of solid waste. This is an alarm to safety of public health and aquatic environment in tropics.

Bacterial density was observed in liver, spleen, kidneys, muscles, and gills of freshwater fish Channa punctatus under stress from heavy metals including cadmium (Cd), chromium (Cr) (hexavalent) and lead (Pb) individually. Maximum density of aerobic heterotrophic bacteria was observed as colony forming units per gram (cfu gm−1) of gills (TNTC), kidneys (2.8 × 104 cfu gm−1) and liver (1 × 104 c.f.u. gm−1) after Cd exposure followed by muscles (9.5 × 103 cfu gm−1) and spleen (8 × 103 cfu gm−1) after exposure to Pb and Cr, respectively. Random isolates, identified as Aeromonas sp., were examined for their antibiotic susceptibility and hemolytic activity. Multiple antibiotic resistance (MAR) to amoxycillin, chloramphenicol, nalidixic acid, and trimethoprim was exhibited by 50–90% of test aeromonads. Production of α-hemolysin was shown by 3% of isolates with β-hemolysin by 5% of isolates of Aeromonas sp. These data indicate that pollution due to toxic metals in aquatic ecosystem enhances density and pathogenic characteristics of bacteria in fish organs, which may pose a risk to fish fauna and public health.

Pollution indicator bacteria such as coliforms, fecal coliforms, and fecal streptococci were enumerated using a multiple-tube fermentation method in 100 treated drinking-water samples from 20 locations in residential, commercial, and industrial areas of a tropical city during summer. Thirty-four percent of the samples were bacteriologically nonpotable. Maximum coliform-contaminated (27%) samples were derived from industrial areas, while samples contaminated with fecal coliform (23%) and fecal streptococci (20%) originated from commercial areas. Coliforms identified as Escherichia coli, Klebsiella sp., Enterobacter sp., and Citrobacter sp. were present in 29%, 26%, 24%, and 15% of samples, respectively. Fecal coliforms were examined for antibiotic susceptibility with disc diffusion method. All test isolates exhibited multiple antibiotic resistance (MAR) for kanamycin, nalidixic acid, tetracycline, and trimethoprim. Escherichia coli isolates were examined for enterotoxigenicity using the suckling mice bioassay and 60% of the isolates displayed enterotoxigenicity. Data indicate that drinking water contaminated with antibiotic-resistant enterotoxigenic fecal bacteria may be responsible for presence of waterborne diarrheal diseases attributed to therapeutic agents used by urban populations in the tropics.

Faecal contamination is a major causative factor for incidence of water borne infectious diseases. Certain hydrogen sulfide (H 2 S) producing enteric bacteria such as Salmonella sp. and Citrobacter sp., assosiated with coliforms, have been considered for rapid detection of recent faecal contamination in water. The basic H 2 S test medium, modified by adding 0.25 gm/L of L-cystine HCl, was examined for its efficiency with 90 water samples collected from 40 pipe supplies, 20 open wells, 15 hand pumps and 15 different surface water bodies (river, streams and ponds). Sterilized modified culture medium in glass vials was inoculated with 100 mL of each sample and incubated at 20, 25, 30, 35 and 44 ∘ C for 18, 24, 42, 48, 66 and 72 h. Blackening of content in incubated vials was considered positive. For comparison, most probable number (MPN) of coliform and faecal coliform per 100 mL was also estimated in each sample by multiple tube fermentation (MTF) method. H 2 S positive result was exhibited by 78% of samples. Coliform (> 10) and faecal coliform/100 mL were also detected in 59% of samples. Maximum H 2 S positive results (100%) were found with well and surface water samples incubated at 30, 35 and 44 ∘ C for 18 h. Coliform (> 10) and faecal coliform/100 mL were also detected in most of these samples. Pipe supplies (60%) and hand pumps (73%) also exhibited considerable H 2 S production. Coliforms and faecal coliforms were also found in significant number of these samples. Thus, the modified H 2 S test may prove a useful alternative indicator of faecal contamination for water quality surveillance and screening of large number of water samples in short duration, particularly during any outbreak of water borne disease among rural population.

Bacterial populations in some organs, viz., liver, spleen, kidney, gill, and arborescent organ of the catfish Clarias batrachus were enumerated followed by determination of resistance for antibiotics and metals. The total viable counts in these organs, observed, were 2.24×104, 2.08×104, 1.44×104, 1.23×104, and 6.40×103 colony-forming units/mL, respectively. The random bacterial isolates from these fish organs showed resistance in decreasing order for colistin (98%), ampicillin (82%), gentamycin (34%), carbenicillin (28%), tetracyline (20%), streptomycin (12%), and ciprofloxacin (02%). Most of the isolates exhibited an increasing order of tolerance for the metals (μg/mL) copper (100), lead (200), manganese (400), cadmium (200), and chromium (50), with minimum inhibitory concentration (MIC) ranging from <50 to 1600 μg/mL. These observations indicate that the significant occurrence of bacterial population in organs of fish with high incidence of resistance for antibiotics and metals may pose risk to fish fauna and public health.

One thousand three-hundred and ninety-four drinking water sources comprising ground water, surface water and piped supplies were tested in order to compare the presence-absence (P-A) test with standard MPN method to detect coliforms as indicators of water quality. Out of 1394 samples, 1074 (77.04%) and 1030 (74.88%) were positive by the MPN and P-A test, respectively. The P-A test detected 96% of the positives detected by the MPN test. The P-A test may be effectively used as a rapid screening method to detect coliform contamination in less polluted sources such as ground water and piped supplies.

A total of 89 drinking water samples from 56 springs, 28 dug wells and 5 streams were analysed for bacterial contamination. About 49.4% of samples showed presence of coliform sp. Recovery of Escherichia coli was maximum followed by Citrobacter freundii > C. koseri > Klebsiella aerogenes > K. ozaenae > Enterobacter cloacae and > E. liquefacience. Out of total coliform isolates 36.4% exhibited resistance for varying number of antibiotics (12 nos.). Resistance for ampicillin (56.8%) was maximum followed by cephaloridine. (45.5%) and cephazolin (47.7%). Half of isolates exhibited multiple (> 2) antibiotic resistance. All isolates also exhibited tolerance for different minimum inhibitory concentrations (MICs) of heavy metals (10 nos). Higher MICs of zinc, copper and lead were observed for 93.7%, 88.6% and 50% of isolates, respectively.

A total of 1094 water samples from 326 springs, 207 streams, 183 dug wells, 151 piped supplies, 90 tube wells, 75 hand pumps, 60 rivers and 2 lakes were collected from eight northern and six north-eastern districts of India. Samples were analysed to assess their potability by estimating the level of heavy metals and bacterial (coliform and faecal coliform) contaminations. Iron was found in a maximum number (53%) of water samples from hand pumps, followed by lead in 43% of the tube wells, chromium in 16% of dug wells, cadmium in 13% of streams and manganese in 7% of hand pumps above their maximum admissible concentrations (MACs). Maximum metal pollution has been observed in a considerable number of water samples from Doda, followed by Almora, Mirzapur and Bankura. Hand pump water samples exhibited maximum metal pollution followed by dug well, spring, stream and river water samples. Contamination of coliform and/or faecal coliform bacteria ranged between 41% and 67% of water samples from open water sources but it was also less, i.e. 6-15% of water samples from tube wells and hand pumps. In general, 42-85% of water samples from districts surveyed, except from Jammu (18%) and Mirzapur (27%), were found to be bacteriologically unsatisfactory. Since toxic metals and pathogenic bacteria pose a risk to public health, monitoring of drinking water sources is required.

Aeromonas species were recovered from three rivers viz. Indus, Yamuna and Gomati over a period of 1-12 months. Around 94 ground water sources were also included in the study. Higher number of A.hydrophila (65.6%) were recovered from unpolluted waters of river Indus. In plains, significant number of A.caviae (30-40%) were recovered from polluted waters of rivers Yamuna and Gomati. In ground water sources polluted with sewage, A.caviae formed 37-68% of total aeromonads recovered. The findings indicate that A.caviae is a dominant species in waters contaminated by sewaqe and wastewater and thus potential indicator of sewage pollution.

A total of 490 isolates of aerobic heterotrophs from the river Indus at Leh and the Gomati at Lucknow were identified into 16 genera. There were 213, 105 and 172 isolates from the river Indus, upstream and downstream of the river Gomati, respectively. Bacteriological and physicochemical analyses showed the increased values with riverine pollution. Gram negative bacilli were dominant and ranged between 79-93%. Aeromonas spp. was the commenst among the genera isolated from the Indus (51%) and downstream (30%) of the river Gomati. Spore-forming Bacillus spp. was recovered in higher numbers from the river Indus (14%) and, upstream (13%) of the river Gomati, while Micrococcus spp. were found in increased numbers from downstream (13%) of the river Gomati. The incidence of resistance for four antibiotics was determined among these isolates. Total and multiple antibiotic resistances were found to be highest among the isolates from downstream. while they were lowest among the isolates from upstream of the river Gomati. Ampicillin resistance was observed in 80% of aeromonads from the river Indus. Sewage contamination was considered to be responsible for predominance of some genera and antibiotic resistant isolates from downstream of the river Gomati. The increased resistance among isolates from the river Indus may be attributed to less pollution with low nutrient level.

The bacteriological analysis of 50 drinking water samples from various sources in different parts of Lucknow city showed coliforms (>10/100ml) and faecal coliforms (>1/100ml) in 56% and 44% of samples, respectively. Escherichia coli were isolated from 13 samples. All the isolates were found to be enterotoxigenic. Out of the total E. coli strains only six exhibited antibiotic resistance. Multiple and single resistances were found in 4 and 2 resistant strains, respectively. These strains also showed transfer of their antibiotic resistances at significant frequencies. Presence of transferable antibiotic resistance, particularly in enterotoxigenic E.coli in drinking water due to the faecal contamination, is a major factor for incidences of various diarrhoeal diseases.

Seasonal variation in distribution of Vibrio cholerae non-O1 and other indicator organisms in Gomati River water along with pH, temperature and percent transmittance was determined for a period of one year. The increased incidence of V. cholerae non-O1 was observed in sewage-contaminated water during warmer months. A significant correlation was found among the heterotrophs, fecal coliforms and fecal streptococci. Of the test strains isolated during summer and monsoon (March-October), 12% showed hemolysin production, while 52% were found to cause fluid accumulation in suckling mice. The isolates also exhibited highest resistance for ampicillin.

The total and thermotolerant coliform counts in rural drinking water derived from ground water, piped supplies and surface water are reported for a number of areas in India. To evaluate these counts as indicators of recent faecal contamination the total coliforms and thermotolerant coliforms isolated have been identified. Thermotolerant Escherichia coli formed 11.7% of the total coliforms and 75.1% of the thermotolerant coliforms. Citrobacter sp. (20.4%) and Klebsiella sp. (50.9%) were the other common total coliforms isolated and, among the thermotolerant coliforms, Klebsiella sp. (16.4%) was the only other organism frequently encountered. The total coliform counts were significantly correlated with water temperature. The applicability in tropical areas of standards developed for temperate climates is discussed.

Water samples from 30 rivers in northern and north-eastern hilly states of India were analysed for bacteriological and physicochemical parameters along with metals and pesticide residues. It was found that 34% of samples had >50 coliforms/100 ml, while 24% of samples demonstrated >50 thermotolerant (faecal) coliforms/100 ml. Among the metals, iron was found to be above maximum permissible limits in the rivers of all the states, while manganese was found to be above the maximum permissible limit in the rivers of Tripura and some northern states. Zinc, lead, nickel, chromium, copper, cobalt and cadmium plus physicochemical parameters and residual pesticides, however, were within their maximum permissible limits.

A total of 231 thermotolerant coliforms was isolated from rural drinking water from four states of India. Of these, 220 isolates were resistant to ampicillin, chloramphemicol, streptomycin and tetracycline. Multiple (MAR), double and single antibiotic resistances were observed in 31.4, 48.6 and 13.7% of the isolates, respectively. Out of 177 antibiotic-resistant isolates examined for transmissibility, only 15.3% were able to transfer their resistances to Escherichia coli K-12 recipient. The resistances were transferred by 32.5% of MAR, 21.9% of double resistant and 7.6% of single resistant isolates. Ampicillin resistance was transferable in 14.69% strains while resistances for the rest of the antibiotics were transferable in less than 4% strains. MAR strains of E. coli and Klebsiella sp. showed highest levels of R-plasmid transfer.

The antibiotic sensitivity of 197 coliform sp. isolated from drinking water in five rural areas was studied. Twelve strains (6.1%) showed multiple antibiotic resistance, three (1.5%) of which were able to transfer the resistances to an Escherichia coli K-12 recipient. It seems unlikely that the occurrence of transmissible multiple antibiotic resistance among coliforms in drinking water in the areas studied poses a significant public health risk.

AbstractThe fatty‐acid composition of the body and visceral fats of Stromateus cinereus (an Indian ‘boundary’ fish) was studied by lithium salt‐acetone, lead salt‐alcohol fractionations and further by methyl ester distillation. The fats are of intermediate type and form a distinct class from fresh water and marine fish fats although the degree of unsaturation is of the same order in all three types of fats. As compared with British ‘boundary’ fish fats, these fats are more saturated.