Impact of long-term wastewater application on microbiological properties of vadose zone

Impact of wastewater irrigation on some biological properties was studied in an area where treated sewage water is being supplied to the farmers since 1979 in the western part of National Capital Territory of New Delhi under Keshopur Effluent Irrigation Scheme. Three fields were selected which had been receiving irrigation through wastewater for last 20, 10 and 5 years. Two additional fields were selected in which the source of irrigation water was tubewell. The soil bacterial and fungal population density was studied in soil layers of 0?C15, 15?C30, 30?C60 and 60?C120 cm depths. Groundwater samples were collected from the piezometers installed in the field irrigated with sewage water for last 20, 10 and 5 years. Results indicate that there was significant increase in bacterial and fungal count in sewage-irrigated soils as compared to their respective control. The population density of bacteria and fungi in waste water-irrigated soils increased with the duration of sewage water application and decreased with increasing depth. The bacterial and fungal count was also directly proportional to organic carbon, sand and silt content and negatively correlated to the clay content, electrical conductivity, pH and bulk density of the soil. Groundwater under sewage-irrigated fields had higher values of most probable number (MPN) index as compared to that of tubewell water-irrigated fields. All the shallow and deep groundwaters were found to be contaminated with faecal coliforms. The vadose zone had filtered the faecal coliform to the tune of 98?C99%, as the MPN index was reduced from ??18,000 per 100 ml of applied waste water to 310 per 100 ml of groundwater under 20 years sewage-irrigated field. The corresponding values of MPN were 250 and 130 per 100 ml of shallow groundwater under 10 and 05 years sewage-irrigated fields, respectively. Rapid detection of faecal contamination suggested that the Citrobacter freundii and Salmonella were dominant in shallow groundwater, while Escherichia coli was dominant in deep groundwater collected from sewage-irrigated field.     

Intensive water quality monitoring in a Taiwan bathing beach

A total of 357 water samples were collected from a public beach in northern Taiwan during beach season, and the densities of enterococci were analyzed by Enterolert methods. The mean enterococci level was 356 MPN/100 ml and ranged from <10 to 2,005 MPN/100 ml, which was classified as high contamination level according to the WHO water quality guideline (95 percentile >1,000 MPN/100 ml). Most of the deteriorated water quality conditions occurred during rainfall. By excluding data from the rain days, the overall beach water quality would be considered in the moderate contamination level (95 percentile 200-1,000 MPN/100 ml). Among the selected microbiological parameters tested, the densities of total coliforms and enterococci exhibited the highest correlation (r = 0.449, p = 0.009), followed by the concentrations of total coliforms and fecal coliforms (r = 0.403, p = 0.02). Nonetheless, no significant correlation was found between enterococci and fecal coliform levels (r = 0.197, p = 0.271).     

Non-radiological contaminants from uranium mining and milling at Ranger,Jabiru, Northern Territory,Australia

Protection from the hazards from radioactivity is of prime importance in the management of uranium mine and mill wastes. Such wastes also contain non-radiological contaminants (heavy metals, acids and neutralising agents) which give rise to potential long-term health and environmental hazards and short-term hazards to the aquatic ecosystem, e.g. as a result of release of waste water. This study seeks to identify non-radiological contaminants (elements) transferred to waste water at the Ranger uranium mine/mill complex at Jabiru, which are likely to hazardous to the aquatic environment. The two principal sources of contaminants are:

1. ore and waste rock mobilised from mining; and
2. process reagents used in the milling and mineral extraction process.

These substances may or may not already be present in the natural environment but may lead to deleterious effects on the aquatic environment if increased above threshold levels. Rhenium, derived from the ore body, was found to be significantly enriched in waste water from Ranger, indicating its suitability as an indicator element for water originating from the mining and milling process, but only uranium, likewise derived from the ore, and magnesium, manganese and sulfur (as sulfate) from the milling process were found to be significant environmental contaminants.     

Improving Salmonella determination in Sinaloa rivers with ultrafiltration and most probable number methods

Monitoring of waterborne pathogens is improved by using concentration methods prior to detection; however, direct microbial enumeration is desired to study microbial ecology and human health risks. The aim of this work was to determine Salmonella presence in river water with an ultrafiltration system coupled with the ISO 6579:1993 isolation standard method (UFS-ISO). Most probable number (MPN) method was used directly in water samples to estimate Salmonella populations. Additionally, the effect between Salmonella determination and water turbidity was evaluated. Ten liters or three tenfold dilutions (1, 0.1, and 0.01 mL) of water were processed for Salmonella detection and estimation by the UFS-ISO and MPN methods, respectively. A total of 84 water samples were tested, and Salmonella was confirmed in 64/84 (76%) and 38/84 (44%) when UFS-ISO and MPN were used, respectively. Salmonella populations were less than 5 × 10(3) MPN/L in 73/84 of samples evaluated (87%), and only three (3.5%) showed contamination with numbers greater than 4.5 × 10(4) MPN/L. Water turbidity did not affect Salmonella determination regardless of the performed method. These findings suggest that Salmonella abundance in Sinaloa rivers is not a health risk for human infections in spite of its persistence. Thus, choosing the appropriate strategy to study Salmonella in river water samples is necessary to clarify its behavior and transport in the environment.     

液液萃取-气质联用法测定饮用水源地水中SVOCs

采用乙酸乙酯-正己烷混合溶剂（体积比为2∶1）对饮用水源地水中阿特拉津、林丹、邻苯二甲酸二正丁酯（DBP）、邻苯二甲酸二（2-乙基己基）酯（DEHP）和滴滴涕（含4种）等8种半挥发性有机物进行1次水样萃取，用气质联用法同时测定。试验表明，方法在25．0μg/L～500μg/L范围内线性良好；检出限在0．006μg/L ～0．028μg/L 之间；空白水样3个质量浓度水平的加标回收率为87．6％～109％，平行测定6次的 RSD＜5．1％；测定集中式生活饮用水源地的实际水样，未检出目标化合物，加标回收率为98．6％～109％。     

毛细管柱气相色谱法测定工业废气和废水中N,N-二甲基甲酰胺

采用HP-INNOWAX毛细管柱、气相色谱氢火焰离子化检测器测定工业废气和废水中的N,N-二甲基甲酰胺,可能共存的丙酮、乙醇和乙酰丙酮均对测试无干扰.方法在0.939 mg/L～75.1 mg/L范围内线性良好,对工业废水、无组织排放工业废气和有组织排放工业废气中N,N-二甲基甲酰胺的检出限分别为0.47 mg/L、0.16 mg/m3和0.31 mg/m3,标准溶液平行测定的RSD为1.9％ ～2.2％,废水样品加标回收率为94％～ 97％.     

Seasonal and spatio-temporal distribution of faecal-indicator bacteria in Tyume River in the Eastern Cape Province, South Africa

We assessed the incidence of faecal-indicator bacteria in Tyume River over a 12-month period between August 2010 and July 2011. Total coliforms, faecal coliforms and enterococci were determined by the membrane filtration method. Total coliforms were detected in counts ranging from 2.1?×?10² to 3.4?×?10⁴?CFU/100 ml. Faecal coliform counts ranged from 1?×?10² to 1.6?×?10⁴?CFU/100 ml while enterococci counts were in the range of 3.3?×?10¹ to 5.1?×?10³?CFU/100 ml. Indicator bacteria counts increased from upstream to downstream sampling sites. Counts of indicator bacteria at all sites were significantly affected by seasonal changes. The bacteriological qualities of the river water were poor, exceeding the guideline of 200 CFU/100 ml and 33 CFU/100 ml for faecal coliforms and enterococci, respectively, for recreational water. Faecal coliform counts also exceeded the 1,000 CFU/100 ml guideline for water used in fresh produce irrigation. Microbial source tracking results showed that faecal pollution was predominantly of human origin during spring at all sampling sites. During other seasons, human faecal pollution was largely confined to midstream and downstream sampling sites. Generally, the presence of faecal-indicator bacteria in the river water samples suggests faecal pollution of this freshwater resource, raising the possibility of the presence of pathogenic microorganisms in the water and a threat to public health.     

Assessment of drinking water quality using ICP-MS and microbiological methods in the Bholakpur area,Hyderabad, India

A total of 16 people died and over 500 people were hospitalized due to diarrhoeal illness in the Bholakpur area of Hyderabad, India on 6th May 2009. A study was conducted with immediate effect to evaluate the quality of municipal tap water of the Bholakpur locality. The study consists of the determination of physico-chemical properties, trace metals, heavy metals, rare earth elements and microbiological quality of drinking water. The data showed the variation of the investigated parameters in samples as follows: pH 7.14 to 8.72, EC 455 to 769 μS/cm, TDS 303.51 to 515.23 ppm and DO 1.01 to 6.83 mg/L which are within WHO guidelines for drinking water quality. The water samples were analyzed for 27 elements (Li, Be, B, Na, Mg, Al, Si, K, Ca, V, Cr, Mn, Fe, Ni, Co, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Sb, Ba and Pb) using inductively coupled plasma-mass spectrometry (ICP-MS). The concentrations of Fe (0.12 to 1.13 mg/L), Pb (0.01 to 0.07 mg/L), Cu (0.01 to 0.19 mg/L), Ni (0.01 to 0.15 mg/L), Al (0.16 to 0.49 mg/L), and Na (38.36 to 68.69 mg/L) were obtained, which exceed the permissible limits of the World Health Organization (WHO) for drinking water quality guidelines. The remaining elements were within the permissible limits. The microbiological quality of water was tested using standard plate count, membrane filtration technique, thermotolerant coliform (TTC), and most probable number (MPN) methods. The total heterotrophic bacteria ranged from 1.0 × 10⁵ to 18 × 10⁷ cfu/ml. Total viable bacteria in all the water samples were found to be too numerable to count and total number of coliform bacteria in all water samples were found to be of order of 1,100 to >2,400 MPN index/100 ml. TTC tested positive for coliform bacteria at 44.2°C. All the water samples of the study area exceeded the permissible counts of WHO and that (zero and minimal counts) of the control site (National Geophysical Research Institute) water samples. Excessively high colony numbers indicate that the water is highly contaminated with microorganisms and is hazardous for drinking purposes. Bacteriological pollution of drinking water supplies caused diarrhoeal illness in Bholakpur, which is due to the infiltration of contaminated water (sewage) through cross connection, leakage points, and back siphoning.     

Ecosystem evaluation (1989–2012) of Ramsar wetland Deepor Beel using satellite-derived indices

The unprecedented urban growth especially in developing countries has laid immense pressure on wetlands, finally threatening their existence altogether. A long-term monitoring of wetland ecosystems is the basis of planning conservation measures for a sustainable development. Deepor Beel, a Ramsar wetland and major storm water basin of the River Brahmaputra in the northeastern region of India, needs particular attention due to its constant degradation over the past decades. A rule-based classification algorithm was developed using Landsat (2011)-derived indices, namely Normalised Difference Water Index (NDWI), Modified Normalised Difference Water Index (MNDWI), Normalised Difference Pond Index (NDPI), Normalised Difference Vegetation Index (NDVI) and field data as ancillary information. Field data, ALOS AVNIR and Google Earth images were used for accuracy assessment. A fuzzy accuracy assessment of the classified data sets showed an overall accuracy of 82 % for MAX criteria and 90 % for RIGHT criteria. The rules were used to classify major wetland cover types during low water season (January) in 1989, 2001 and 2012. The statistical analysis of the classified wetland showed heavy manifestation in aquatic vegetation and other features indicating severe eutrophication over the past 23 years. This degradation was closely related to major contributing anthropogenic factors, such as a railway line construction, growing croplands, waste disposal and illegal human settlements in the wetland catchment. In addition, the landscape development index (LDI) indicated a rapid increase in the impact of the surrounding land use on the wetland from 1989 to 2012. The techniques and results from this study may prove useful for top-down landscape analyses of this and other freshwater wetlands.     

Adsorption of Cotton Fabric Dyestuff Waste Water on Nigeria Agricultural Semi-Activated Carbon

The Kaduna river in Nigeria is in such great environmental stress that the self-purifying capacity of the river has been exceeded as a result of industrial discharges. The river water is blue-green and pollution build-up is evident on the river banks. Techniques were designed to rid the river of visible signs of pollution by incorporating the principles of adsorption and incineration.Semi-activated carbon from agricultural wastes were used to treat the waste water. Residual colors, amber, yellow and orange, were obtained and the solute removed ranged from 96-99.8% and the volatile residue removed by carbon treatment ranged from 3-3.8%. Incineration of 1 kg waste water yielded 40 g solid residue.Adsorption of dyestuff present in the waste water was linear and increased with concentrations of waste water per unit mass of guinea corn carbon. Replicate results yielded: y = 2.5 + 0.130x y = 2.306 + 0.017x where x =log10% concentration of dyestuff waste water (independent variable); y = log10 adsorption of dyestuff waste-weight gramme-1 carbon. Unit of weight = milligramme (dependent variable).For maize carbon, adsorption was linear but decreased with increasing concentrations. Replicate results were: y = 1.583 - 0.21x y = 0.52 - 0.32x x and y here are the same as above; with cane sugar carbon, adsorption was independent of concentrations. Student t-test showed no statistical difference between the replicates at the 99.5% level.     

Monitoring of Coliforms and chlorine residual in water distribution network of Rawalpindi, Pakistan

The present study was undertaken to examine the drinking water quality of Rawal Treatment Plant, Rawalpindi and its distribution network by collecting samples from eight different locations. The aim was to determine potential relationship between the presence of microorganisms and chlorine residual in the distribution network. Quantification of chlorine residual, turbidity, standard plate count (SPC), fecal and total coliforms by Most Probable Number (MPN) was performed. Three different forms of chlorine were measured at each sampling station such as free chlorine, residual chlorine, chloramines and total chlorine residual. A critical evaluation of data presented indicated that pH generally ranged from 7.02–7.30; turbidity varied from 0.34–2.79 NTU; conductivity fluctuated from 359–374 μS/cm; and TDS values were found to be ranging between 180–187 mg/l. Station # 7 was found to be most contaminated. The value of total chlorine was found to be 0.86 to1.7 mg/l at Station # 3 and 6, respectively. Highest standard plate count was 62 CFU/ml at Station # 7. Total coliforms were less than 1.1 MPN/100 ml at almost most of the stations except at Station # 3 where it was found to be greater than 23.0 MPN /100 ml. Overall aim of this study is to create awareness about contamination of drinking water in the water distribution networks and to make recommendations to provincial agencies such as EPA, CDA and WASA that regular monitoring should be carried out to ensure that the chlorine residual is available at consumer end.     

Determination of traces of copper and zinc in honeys by the solid phase extraction pre-concentration followed by the flame atomic absorption spectrometry detection

A simple and fast solid phase extraction procedure was developed to pre-concentrate traces of Cu and Zn prior to their determination in honey samples by flame atomic absorption spectrometry. The sample preparation included dissolution of honey samples and the passage (at 20 ml/min) of resulting 10 % m/v solutions (100 ml) through Dowex 50W?×?8-400 resin beds in order to quantitatively retain Cu and Zn and separate them from the glucose and fructose matrix. Enriched Cu and Zn traces were recovered with 5.0 ml of a 3.0 mol/l HCl solution and quantified by flame atomic absorption spectrometry. The procedure proposed was used to analyze sixty nine commercially available and freshly ripened honey samples coming from the Lower Silesia region (Poland). It enabled to measure Cu and Zn within the range of 0.01–1.42 and 0.03–15.38 μg/g, respectively, with precision better than 4 %. Accuracy, assessed on the basis of the recovery test and the comparison of results with those obtained using wet digestion and inductively coupled plasma optical emission spectrometry, was ranged from ?4 % to +6 %. Detection limits of Cu and Zn achieved with this method were 5 and 7 ng/g, respectively.     

Physicochemical and microbiological assessment of recreational and drinking waters

The present study was aimed to make an assessment of health risk due to pollution and human pathogenic bacteria associated with the recreational and drinking water sources in twin densely populated holy Indian cities Ayodhya and Faizabad. Though physicochemical studies revealed that the water available in the area is under recommended limits for human use, it is unsafe on account of poor microbiological quality of surface and ground water in the region. The most probable number (MPN) test results revealed the preponderance of ≥2,400 total coliforms (TC) (100 ml)^− 1 in river, pond, dug well and kund waters. Contrary to that, 94% tube wells, 32% hand pumps and 25% piped supply water were under safe limits having <3 TC (100 ml)^− 1. The shallow depth (~40 ft), water logging and presence of septic tanks in the near vicinity are the possible reasons of poor microbial quality of hand pump drinking water. The municipal supply water passes along sewage line where loose connections and/or cracks in pipe lead to mixing and contamination. The significant best quality of tube well water evident from the absence of TC could be attributed to the depth of well ≥150 ft and usually their location away from the habitation. A total of 263 bacteria from 186 water samples were isolated, and at least five genera of enteric bacteria from various water sources were identified morphologically and biochemically as Escherichia coli, Klebsiella sp., Enterobacter sp., Shigella sp. and Salmonella sp. The serotyping of 72 E. coli and 36 Salmonella sp. revealed 51 as E. coli O157 and 20 as Salmonella sp. The presence of enteric pathogens in water sources pose threat to human health and therefore call for immediate remedial measures.     

Occurrence,removal and health risk assessment of phthalate esters in the process streams of two different wastewater treatment plants in Lagos and Ogun States,Nigeria

Phthalate esters (PEs) are one of the environmentally active organic pollutants capable of causing endocrine disruption. The levels of PE congeners were determined in the influent and effluent from Covenant Oxidation Pond (COP) and Ikeja Wastewater Treatment Plant (IWWTP). Standard methods were adopted for determining the physical and chemical parameters of the water samples. The water samples for PE congener’s determination were collected, acidified and stored at 4 °C prior to liquid-liquid extraction and analysis by gas chromatograph. The possible health risk associated with the usage of effluent-polluted river water was also investigated. The pH and temperature ranges were within the Federal Ministry of Environment (FME) 2001 guideline limits while the dissolved oxygen, biochemical oxygen demand and chemical oxygen demand were above the limits. The IWWTP performed better at removing PEs at 54% compared to 43.3% on average at COP. The health risk of individual PE congener showed no non-cancer effects (HQ) as the values varied from 5.01E?05 (DAP) to 1.52E?02 (DEHP) for adults and 1.17E?04 (DAP) to 3.76E?03 (DBP) for children at COP, while at IWWTP, it ranged from 8.06E?05 (DIBP) to 1.09E?02 (DEHP) for adults and 5.68E?04 (MMP) to 2.54E?02 (DEHP) for children. Notwithstanding, the usage of effluent-polluted river water by local communities downstream may result in carcinogenic effects due to the cumulative effects of the PE congeners as the values obtained for adults and children for the ingestion and dermal routes for the two waste process streams ranged from 4.67E?06 (IWWTP) to 6.22E?05 (IWWTP) and 2.18E?05 (IWWTP) to 7.18E?05 (COP), respectively.     

电导和直流安培双检测器离子色谱法测定清洁水样中的碘化物

选用配备了2种不同检测器(电导检测器和直流安培检测器)的离子色谱仪对稀释后过0.22μm滤膜的水样进行分析。配备有直流安培检测器的离子色谱仪测定水中碘化物的方法在0.100~20.0μg/L范围内线性关系良好,相关系数(r)=0.9999,方法检出限为0.030μg/L,测定下限为0.120μg/L,样品加标回收率为95.0%~104%,相对标准偏差为1.06%~1.64%;配备有电导检测器的离子色谱仪测定水中碘化物的方法在20.0~2.00×105μg/L范围内线性关系良好,相关系数(r)=0.9995,方法检出限为2.00μg/L,测定下限为8.00μg/L,样品加标回收率为99.0%~110%,相对标准偏差为0.71%~3.12%。离子色谱-直流安培检测器法测定水中碘化物的方法准确度高、灵敏度高、精密度好,检出限相对较低,适用于测定ρ(碘化物)≤20.0μg/L的清洁水样;离子色谱-电导检测器法主要适用于测定ρ(碘化物)≥20.0μg/L的水样。     

Bacterial communities in urban aerosols collected with wetted-wall cyclonic samplers and seasonal fluctuations of live and culturable airborne bacteria

Airborne transmission of bacterial pathogens from point sources (e.g., ranches, dairy waste treatment facilities) to areas of food production (farms) has been suspected. Determining the incidence, transport and viability of extremely low levels of pathogens require collection of high volumes of air and characterization of live bacteria from aerosols. We monitored the numbers of culturable bacteria in urban aerosols on 21 separate days during a 9 month period using high volume cyclonic samplers at an elevation of 6 m above ground level. Culturable bacteria in aerosols fluctuated from 3 CFU to 6 million CFU/L of air per hour and correlated significantly with changes in seasonal temperatures, but not with humidity or wind speed. Concentrations of viable bacteria determined by fluorescence staining and flow cytometry correlated significantly with culturable bacteria. Members of the phylum Proteobacteria constituted 98% of the bacterial community, which was characterized using 16S rRNA gene sequencing using DNA from aerosols. Aquabacterium sp., previously characterized from aquatic environments, represented 63% of all clones and the second most common were Burkholderia sp; these are ubiquitous in nature and some are potential human pathogens. Whole genome amplification prior to sequencing resulted in a substantial decrease in species diversity compared to characterizing culturable bacteria sorted by flow cytometry based on scatter signals. Although 27 isolated colonies were characterized, we were able to culture 38% of bacteria characterized by sequencing. The whole genome amplification method amplified DNA preferentially from Phyllobacterium myrsinacearum, a minor member of the bacterial communities, whereas Variovorax paradoxus dominated the cultured organisms.     

Polycyclic aromatic hydrocarbon concentrations,mutagenicity, and Microtox® acute toxicity testing of Peruvian crude oil and oil-contaminated water and sediment

The oil industry is a major source of contamination in Peru, and wastewater and sediments containing oil include harmful substances that may have acute and chronic effects. This study determined polycyclic aromatic hydrocarbon (PAH) concentrations by GC/MS, mutagenicity using TA98 and TA100 bacterial strains with and without metabolic activation in the Muta-ChromoPlate? test, and Microtox® 5-min EC₅₀ values of Peruvian crude oil, and water and sediment pore water from the vicinity of San José de Saramuro on the Marañón River and Villa Trompeteros on the Corrientes River in Loreto, Peru. The highest total PAH concentration in both areas was found in water (Saramuro?=?210.15 μg/ml, Trompeteros?=?204.66 μg/ml). Total PAH concentrations in water from San José de Saramuro ranged from 9.90 to 210.15 μg/ml (mean?=?66.48 μg/ml), while sediment pore water concentrations ranged from 2.19 to 70.41 μg/ml (mean?=?24.33 μg/ml). All water samples tested from Saramuro and Trompeteros sites, and one out of four sediment pore water samples from Trompeteros, were found to be mutagenic (P?<?0.001). One sediment pore water sample in Saramuro was determined to have a measurable toxicity (Microtox EC₅₀?=?335.1 mg/l), and in Trompeteros, the EC₅₀ in water and sediment pore water ranged from 25.67 to 133.86 mg/l. Peruvian crude oil was mutagenic using the TA98 strain with metabolic activation, and the EC₅₀ was 17.18 mg/l. The two areas sampled had very high PAH concentrations that were most likely associated with oil activities, but did not lead to acute toxic effects. However, since most of the samples were mutagenic, it is thought that there is a greater potential for chronic effects.     

Biomonitoring ²¹°Po and ²¹°Pb in marine brachyuran crabs collected along the coast of Kudankulam, Gulf of Mannar (GOM), India

Activities of 21?Po and 21?Pb in whole-body and in various tissues of brachyuran crabs collected along the Kudankulam coast were studied. A non-uniform distribution of these radionuclides was observed between the various tissues. Of all the tissues, 21?Po and 21?Pb were found to accumulate more in the hepatopancreas and intestine. Among the crabs studied, Charybdis lucifera registered higher 21?Po and 21?Pb activity. Muscle tissue in all the species registered lower activity. The 21?Po/21?Pb activity ratio was found to be greater than unity. The biological concentration factor for organs varied between ~ 10? and 10? for 21?Po and ~102 and 10? for 21?Pb. A significant variation in the accumulation of 21?Po and 21?Pb was noted between species and between seasons (p < 0.05). The mean whole-body internal dose ranged from 1.42 to 6.86 μGy h?1 for 21?Po and from 3.0 × 10?3 to 8.0 × 10?3 μGy h?1 for 21?Pb. The external dose for 21?Po and 21?Pb was 2.41 × 10?? to 5.76 × 10?? μGy h?1 and 4.14 × 10?? to 8.26 × 10?? μGy h?1, respectively. The activity levels recorded are in agreement with values recorded in related organisms in other parts of the world. The total committed effective dose due to the intake of both radionuclides ranged from 80.3 to 871.7 μSv y?1. The median dose calculated due to 21?Po and 21?Pb in certain crabs in Kudankulam is less and would not pose any significant radiological impact on health or a cancer risk to the public, and the seafood is considered safe for human consumption.     

A field test for the assessment of faecal contamination of potable water

A simple, sensitive, rapid, inexpensive paper strip impregnated with Salmonellal E. coli medium (SEM) was formulated, and placed in a test tube. When potable water of 10 ml was added to the test tube it detected the faecal contamination of water samples within 16-48 h when incubated at room temperature from 20 to 35 degrees C. The positive results were indicated when the medium turned black (hydrogen sulfide production) for the presence of Salmonella sp. and/or the formation of a red ring (free indole from tryptophan) when a few drops of Kovac's reagent was added for the presence of coliform bacteria (E. coli). More than 600 water samples were tested with the new test (SEM) and results showed 99% agreement with that of the standard most probable number (MPN) coliform test and also proved highly successful in the field when it was employed to detect both Salmonella and E. coli. Different water testing laboratories involved in a water quality monitoring programme and governmental agencies evaluated the test media and reported that the test was user friendly, reliable and simple to perform in the field and will be especially useful for screening of both urban and rural water supplies for routine monitoring of bacteriological contamination.     

Partition of heavy metals in a tropical river system impacted by municipal waste

A research program was established to identify the governing factors for the partition coefficient (K _D ) of heavy metals between suspended particulate and dissolved phases in the Day River system a tropical, highly alluvial aquatic system, in Vietnam. The targeted river system, draining an urbanized–industrialized catchment where discharged wastewater is mostly untreated, could be separated into the least impacted, pristine area, and the most impacted, polluted area. Organic matter degradation was shown to govern the variation of parameters like total organic carbon, biochemical oxygen demand, chemical oxygen demand, nutrients, conductivity, or redox potential. Heavy metals in both dissolved and particulate phases were enriched in severely polluted area because of wastewater inflow that contains concentrated metals and intensification of metal influx from sediment. Results show log K _D in the order Mn?<?As?<?Zn?<?Hg?<?Ni?<?Cu?<?Cd?<?Co?<?Pb?<?Cr?<?Fe and As?<?Zn?<?Ni?<?Mn?<?Cr?<?Cu?<?Co?<?Fe in the polluted zone and the pristine zone, respectively. A decreasing tendency of partition coefficients of 11 heavy metals considered from the pristine to the impacted zones was observed. Three explanations for the difference are: (1) increase of solubility of most heavy metals in low redox potential, (2) competition for the binding sites with major and minor cations, and (3) complexation with dissolved organic matter concentrated in municipal waste impacted water. Apart from domestic waste impact, statistical analysis has contributed to identify the influence of climate condition and hydrological regime to the partition of heavy metals in the area.