Deposition in boreal forests in relation to type, size, number and placement of collectors

Open precipitation and throughfall was collected at a Norway spruce stand in Finland using funnel-type collectors and at a black spruce stand in Canada using trough-type collectors. The presence or absence of a rim on the funnel, funnel diameter (9, 14 and 20 cm) and length of sampling period (1, 2 and 4 weeks) on monthly values were evaluated at the Norway spruce stand, and the number of collectors required for defined levels of accuracy and precision of throughfall loads to be reached and the influence of the spatial arrangement of collectors on solute concentrations was studied at both stands. The presence of a rim had no significant effect on open precipitation and throughfall amounts, but did on throughfall DOC, Ca²⁺, Mg²⁺, K⁺, Na⁺ and Cl⁻ ion loads. Deposition loads increased with decreasing funnel diameter; for open precipitation, this was due to increased catch efficiency while for throughfall the increase was attributed to canopy interaction and leaching of litter trapped in the collectors. Calculated monthly H⁺ loads decreased and those for all other constituents increased with collection period length. Using 15 collectors at the Norway spruce stand would allow throughfall loads to be determined to within 20% of the true mean weekly value with a confidence level of 95% for most solute, but not for NH₄ ⁺–N, NO₃ ⁻–N, Mg²⁺ and SO₄ ²⁻-S. Using 15 trough collectors, the same confidence level at the more heterogeneous black spruce stand would only be achieved for H⁺, Cl⁻, DOC and SO₄ ²⁻-S loads. In both stands, using either random or systematic placements of throughfall collectors gave similar results.     

Characteristic Study of Dry Deposition, Concentration, Compositions for Particulates Mass and Ionic Species During Summer and Autumn Season at a Traffic Sampling Site

Aerosol samples for dry deposition and total suspend particulates (TSP) were collected from August to November of 2003 in central Taiwan. Ion chromatography was used to analyze the related water-soluble ionic species (Cl⁻, NO₃ ⁻, SO₄ ²⁻, Na⁺, NH₄ ⁺, K⁺, Mg²⁺ and Ca²⁺). The results obtained in this study indicated that the ambient air particulate mass concentrations in the daytime period (averaged 975.4 μg m⁻³) were higher than the nighttime period (averaged 542.1 μg m⁻³). And the daytime dry deposition fluxes (averaged 58.12 μg m⁻² sec⁻¹) were about 2.2 times as that of nighttime dry deposition fluxes (averaged 26.54 μg m⁻² sec⁻¹) of the downward dry deposition. The average values downward and upward of dry deposition fluxes for the weekend period were almost higher than the weekday period for either daytime or nighttime period. Furthermore, the average daytime dry deposition fluxes (averaged 26.37 μg m⁻² sec⁻¹) were also about 2.3 times as that of nighttime dry deposition fluxes (averaged 11.52 μg m⁻² sec⁻¹). Moreover, the results also indicate that SO₄ ²⁻ and Ca²⁺ have higher average composition for total suspended particulates in the daytime period while Ca²⁺, SO₄ ²⁻, and Na⁺ have the higher average composition for total suspends particulates in the nighttime period.     

Atmospheric deposition of major and trace elements in Amman, Jordan

Wet and dry deposition samples were collected in the capital of Jordan, Amman. Concentrations of Al, Ba, Bi, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Sb, V, Zn, Fe, Sr, Mg²⁺, Ca²⁺, Na⁺, K⁺, Cl⁻, NO₃ ⁻ and SO₄ ²⁻, along with pH were determined in collected samples. Mean trace metal concentrations were similar or less than those reported for other urban regions worldwide, while concentrations of Ca²⁺ and SO₄ ²⁻ were among the highest. High Ca²⁺ concentrations were attributed to the calcareous nature of the local soil and to the influence of the Saharan dust. However, high SO₄ ²⁻ concentrations were attributed to the influence of both anthropogenic and natural sources. Except for Cl⁻, NO₃ ⁻, SO₄ ²⁻ and Cu, monthly dry deposition fluxes of all measured species were higher than wet deposition fluxes. The annual wet deposition fluxes of trace metals were much lower than those reported for other urban areas worldwide.     

Sulphate, Nitrogen and Base Cation Budgets at 21 Forested Catchments in Canada, the United States and Europe

To assess the concern over declining base cation levels in forest soils caused by acid deposition, input-output budgets (1990s average) for sulphate (SO₄), inorganic nitrogen (NO₃-N; NH₄-N), calcium (Ca), magnesium (Mg) and potassium (K) were synthesised for 21 forested catchments from 17 regions in Canada, the United States and Europe. Trend analysis was conducted on monthly ion concentrations in deposition and runoff when more than 9 years of data were available (14 regions, 17 sites). Annual average SO₄ deposition during the 1990s ranged between 7.3 and 28.4 kg ha⁻¹ per year, and inorganic nitrogen (N) deposition was between 2.8 and 13.8 kg ha⁻¹ per year, of which 41–67% was nitrate (NO₃-N). Over the period of record, SO₄ concentration in deposition decreased in 13/14 (13 out of 14 total) regions and SO₄ in runoff decreased at 14/17 catchments. In contrast, NO₃-N concentrations in deposition decreased in only 1/14 regions, while NH₄-N concentration patterns varied; increasing at 3/14 regions and decreasing at 2/14 regions. Nitrate concentrations in runoff decreased at 4/17 catchments and increased at only 1 site, whereas runoff levels of NH₄-N increased at 5/17 catchments. Decreasing trends in deposition were also recorded for Ca, Mg, and K at many of the catchments and on an equivalent basis, accounted for up to 131% (median 22%) of the decrease in acid anion deposition. Base cation concentrations in streams generally declined over time, with significant decreases in Ca, Mg and K occurring at 8, 9 and 7 of 17 sites respectively, which accounted for up to 133% (median 48%) of the decrease in acid anion concentration. Sulphate export exceeded input at 18/21 catchments, likely due to dry deposition and/or internal sources. The majority of N in deposition (31–100%; median 94%) was retained in the catchments, although there was a tendency for greater NO₃-N leaching at sites receiving higher (<7 kg ha^-1 per year) bulk inorganic N deposition. Mass balance calculations show that export of Ca and Mg in runoff exceeds input at all 21 catchments, but K export only exceeds input at 16/21 sites. Estimates of base cation weathering were available for 18 sites. When included in the mass balance calculation, Ca, Mg and K exports exceeded inputs at 14, 10 and 2 sites respectively. Annual Ca and Mg losses represent appreciable proportions of the current exchangeable soil Ca and Mg pools, although losses at some of the sites likely occur from weathering reactions beneath the rooting zone and there is considerable uncertainty associated with mineral weathering estimates. Critical loads for sulphur (S) and N, using a critical base cation to aluminium ratio of 10 in soil solution, are currently exceeded at 7 of the 18 sites with base cation weathering estimates. Despite reductions in SO₄ and H⁺ deposition, mass balance estimates indicate that acid deposition continues to acidify soils in many regions with losses of Ca and Mg of primary concern. The U.S. Government's right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged. The Canadian Crown reserves the right to retain a non-exclusive, royalty free licence in and to any copyright.     

Hydrogeochemical characterization of contaminated groundwater in Patancheru industrial area,southern India

The groundwater is one of the most contaminated natural resources in Patancheru industrial area due to unplanned and haphazard industrial growth and urbanization without following basic pollution control norms. The rapid industrialization initiated in early 1970 has started showing up its after effects few years later in the form of physiochemical contamination of the both surface and groundwater bodies of the area. It has resulted in local people being deprived of safe drinking water, plant and aquatic life has severely affected, and situation is deteriorating over the years in the area in spite of some preventive and remedial measures being initiated. The focus of the present study is to understand the chemical characteristics of groundwater and geochemical processes the contaminant water is undergoing which are normally imprinted in its ionic assemblages. The water samples collected in pre- and post-monsoon seasons from forty two groundwater and four surface water sources were analyzed for major constituents such as Ca²⁺, Mg²⁺, Na⁺, K⁺, CO₃⁻, HCO₃⁻, Cl⁻, SO₄²⁻, NO₃⁻, and F⁻, and selected samples were tested for ten important trace metals like Fe, Pb, Bi, Mn, Cr, Co, Ni, Cu, Zn, and Cd. Na⁺ among cations and Cl⁻ among anions dominate the water in both the seasons where as Ca²⁺, HCO₃⁻, and Cl⁻ show significant reduction in their ionic strength in post-monsoon. The groundwater in general is of mixed type, but most of it belong to Na⁺–Cl⁻, Na⁺–HCO₃⁻, Ca²⁺–Mg²⁺–HCO₃⁻, and Ca²⁺–Mg²⁺–Cl⁻ facies. The Na⁺ and Ca²⁺ are in the transitional state with Na⁺ replacing Ca²⁺ and HCO₃⁻–Cl⁻ due to physiochemical changes in the aquifer system. The evaluation of hydrochemistry through various ionic indices, ratios, and plots suggest that silicate–carbonate weathering, ion exchange, dissolution, and evaporation processes are responsible for origin of the present chemical status of the groundwater which is also controlled by the contamination from extraneous sources that could have accelerated the dissolution processes. Gibbs plots authenticate that the evolution of water chemistry is influenced by interaction of percolating water with aquifer matrix apart from anthropogenic enrichment of elements which get over concentrated due to evaporation.     

Chemistry of fogs at Agra, India: Influence of soil particulates and atmospheric gases

Fog water samples were collected in the months of December and January during 1998–2000 at Agra, India. The samples were analyzed for pH, major anions (F⁻, Cl⁻, SO₄ ²⁻, NO₃ ⁻, HCOO⁻ and CH₃COO⁻), major cations (Ca²⁺, Mg²⁺, Na⁺ and K⁺) and NH₄ ⁺ using ion chromatography, ICP-AES and spectrophotometer methods, respectively. pH of fog water samples ranged between 7.0 and 7.6 with a volume weighted mean of 7.2, indicating its alkaline characteristic. NH₄ ⁺ contributed 40%, SO₄ ²⁻ and NO₃ ⁻ accounted for 28%, while Ca²⁺, Mg²⁺, Na⁺ and K⁺ accounted for 16% of the total ionic concentration. The ratios of Mg²⁺/Ca²⁺ and Na⁺/Ca²⁺ in fog water indicates that 50–75% of fog water samples correspond to the respective ratios in local soil. Significant correlation between Ca²⁺, Mg²⁺, Na⁺ and K⁺ suggests their soil origin. The order of neutralization, NH₄ ⁺ (1.4) > Ca²⁺ (0.28) > Mg²⁺ (0.12), indicates that NH₄ ⁺ is the major neutralizing species. Fog water and atmospheric alkalinity were also computed and were found to be 873 and 903 neqm⁻³, respectively. Both of these values are higher than values reported from temperate sites and thus indicate that at the present level of pollutants, there is no risk of acid fog problem. The study also shows that the alkaline nature of fog water is due to dissolution of ammonia gas and partly due to interaction of fog water with soil derived aerosols.     

The development of loads of cations, anions, Cd and Pb in precipitation and of atmospheric concentrations of N-components, in Switzerland from 1988 to 2003

This study presents the results of the analyses of Cd, Pb, cations and anions present in precipitation and dust at a pre-alpine and a suburban site in Switzerland in the period from 1988 to 2003. The aim of these measurements was to monitor the success of measures taken to diminish pollutant emissions. No change was found for Ca²⁺, K⁺, Na⁺ and Mg²⁺ loads – in line with expectations, as no reducing measures had been taken. Statistically significant and largely decreasing values (50–90%) were found for Cl⁻ and Cd (linked to the fitting of filters in incineration plants), Pb (unleaded petrol), (diminishing the use of mineral oil with high S content), and the proton (lower HCl and SO₂ emissions). A smaller decrease (up to 30%) or none was registered for oxidised nitrogen components (fitting cars with catalytic converters, but an increase in numbers of cars and trucks). No significant change was found for NH₃ as farming techniques had undergone no major changes. The long-term measurements show that the measures taken to reduce emissions were successful. A shorter monitoring period would have been misleading owing to data variability and temporary incidents e.g. amount of precipitation.     

Quantifying Carbon Budgets Of Conifer Mediterranean Forest Ecosystems, Turkey

Abstact Aboveground biomass, aboveground litterfall, and leaf litter decomposition of five indigenous tree stands (pure stands ofPinus brutia,Pinus nigra,Cedrus libani,Juniperus excelsa, and a mixed stand ofAbies cilicica,P. nigra, andC. libani) were measured in an eastern Mediterranean evergreen needleleaf forest of Turkey. Measurements were converted to regional scale estimates of carbon (C) stocks and fluxes of forest ecosystems, based on general non-site-specific allometric relationships. Mean C stock of the conifer forests was estimated as 97.8± 79 Mg C ha⁻¹consisting of 83.0 ± 67 Mg C ha⁻¹in the aboveground and 14.8 ± 12 Mg C ha⁻¹in the belowground biomass. The forest stands had mean soil organic carbon (SOC) and nitrogen (SON) stocks of 172.0 ± 25.7 Mg C ha⁻¹and 9.2 ± 1.2 Mg N ha⁻¹, respectively. Mean total monthly litterfall was 376.2± 191.3 kg C ha⁻¹, ranging from 641 ± 385 kg C ha⁻¹forPinus brutiato 286 ± 82 kg C ha⁻¹forCedrus libani. Decomposition rate constants (k) for pine needles were 0.0016 forCedrus libani, 0.0009 forPinus nigra, 0.0006 for the mixed stand, and 0.0005 day⁻¹forPinus brutiaand Juniperus excelsa. Estimation of components of the C budgets revealed that the forest ecosystems were net C sinks, with a mean sequestration rate of 2.0 ± 1.1 Mg C ha⁻¹ yr⁻¹ranging from 3.2 ± 2 Mg C ha⁻¹forPinus brutiato 1.6 ± 0.6 Mg C ha⁻¹forCedrus libani. Mean net ecosystem productivity (NEP) resulted in sequestration of 98.4 ± 54.1 Gg CO₂ yr⁻¹from the atmosphere when extrapolated for the entire study area of 134.2 km²(Gg = 10⁹ g). The quantitative C data from the study revealed the significance of the conifer Mediterranean forests as C sinks     

Atmosphic pollutants study of particles ionic species during high wind speed (>7 m s-1) near Taiwan strait in central Taiwan from 2004 to 2005

This study monitored atmospheric pollutants during high wind speed (> 7 m s⁻¹) at two sampling sites: Taichung Harbor (TH) and Wuci traffic (WT) during March 2004 to January 2005 in central Taiwan. The correlation coefficient (R ²) between TSP, PM_2.5, PM_2.5−10 particle concentration vs. wind speed at the TH and WT sampling site during high wind speed (< 7 m s⁻¹) were also displayed in this study. In addition, the correlation coefficients between TSP, PM_2.5 and PM_2.5−10 of ionic species vs. high wind speed were also observed. The results indicated that the correlation coefficient order was TSP > PM_2.5−10 > PM_2.5 for particle at both sampling sites near Taiwan strait. In addition, the concentration of Cl⁻, NO₃ ⁻, SO₄ ²⁻, NH₄ ⁺, Mg²⁺, Ca²⁺ and Na⁺ were also analyzed in this study.     

Persistence and Dissipation Kinetics of Spiromesifen in Chili and Cotton

In a field study carried out at three different locations, the dissipation of spiromesifen on cotton and chili was studied and its DT₅₀, and DT₉₉ were estimated at each location. Spiromesifen was sprayed on chili at 96 and 192 g a.i. ha⁻¹ and cotton at 120 and 240 g a.i. ha⁻¹. Samples of chili fruits were drawn at 0, 1, 3, 5, 7, 10, 15, 21, 30 days after treatment and that of cotton seed and lint at first picking and harvest. Soil samples were drawn 30 days after treatment from 0 to 15 and 15 to 30 cm layer. Quantification of residues was done on GC–MS in Selected Ion Monitoring (SIM) mode in mass range 271–274 m/z. The LOQ of this method was found 0.033 μg g⁻¹, LOD being 0.01 μg g⁻¹. The DT₅₀ of spiromesifen when applied at recommended doses in chili fruits was found to be 2.18–2.40 days. Ninety-nine percent degradation was found to occur within 14.5–16.3 days after application. Residues of spiromesifen were not detected in cotton seed and lint samples at the first picking. In soil, no residues of spiromesifen were detectable 15 days after treatment.     

Spatial variability of the shallow groundwater level and its chemistry characteristics in the low plain around the Bohai Sea,North China

To characterize the spatial distribution of groundwater level (GWL) and its chemistry characteristics in the low plain around the Bohai Sea, shallow groundwater depth of 130 wells were determined. Water soluble ions composition, total dissolved solid (TDS), electric conductivity (EC), total hardness (TH), total alkalinity (TA), and total salt content (TS) of 128 representative groundwater samples were also measured. Classical statistics, geostatistical method combined with GIS technique were then used to analyze the spatial variability and distribution of GWL and groundwater chemical properties. Results show that GWL, TDS, EC, TH, TA, and TS all presented a lognormal distribution and could be fitted by different semivariogram models (spherical, exponential, and Gaussian). Spatial structure of GWL, TDS, EC, TH, TA, and TS changed obviously. GWL decreased from west inland plain to the east coastal plain, however, TDS, EC, and TS increased from west to east, TH and TA were higher in the middle and coastal plain area. Groundwater chemical type in the coastal plain was SO₄²⁻·Cl⁻—Na⁺ while chemical types in the inland plain were SO₄²⁻·Cl⁻—Ca²⁺·Mg²⁺ and HCO₃⁻—Ca²⁺·Mg²⁺.     

Influence of Meteorological Parameters on Particulates and Atmospheric Pollutants at Taichung Harbor Sampling Site

Atmospheric aerosol particles and metallic concentrations, ionic species were monitored at the Experimental harbor of Taichung sampling site in this study. This work attempted to characterize metallic elements and ionic species associated with meteorological conditions variation on atmospheric particulate matter in TSP, PM_2.5, PM_2.5–10. The concentration distribution trend between TSP, PM_2.5, PM_2.5–10 particle concentration at the TH (Taichung harbor) sampling site were also displayed in this study. Besides, the meteorological conditions variation of metallic elements (Fe, Mg, Cr, Cu, Zn, Mn and Pb) and ions species (Cl⁻, NO₃ ⁻, SO₄ ²⁻, NH₄ ⁺, Mg²⁺, Ca²⁺ and Na⁺) concentrations attached with those particulate were also analyzed in this study. On non-parametric (Spearman) correlation analysis, the results indicated that the meteorological conditions have high correlation at largest particulate concentrations for TSP at TH sampling site in this study. In addition, the temperature and relative humidity of meteorological conditions that played a key role to affect particulate matter (PM) and have higher correlations then other meteorological conditions such as wind speed and atmospheric pressure. The parameter temperature and relative humidity also have high correlations with atmospheric pollutants compared with those of the other meteorological variables (wind speed, atmospheric pressure and prevalent wind direction). In addition, relative statistical equations between pollutants and meteorological variables were also characterized in this study.     

Chemical Characteristics of Rain Water at an Urban Site of South Western Turkey

In this study, chemical composition of the rain water in Mugla was investigated from February to April 2002. Rain water samples were obtained from Mugla, a small city in south western Turkey. The Yatagan Power Plant is located 30 km northwest of Mugla city. The values of pH and the concentrations of major ions (Ca²⁺, Na⁺, K⁺, SO₄ ²⁻, NO₃ ⁻, NH₄ ⁺) in the rainwater samples were analyzed. The pH varied from 4.5 to 7.7 with an average of 6.9 which was in alkaline range considering 5.6 as the neutral pH of cloud water with atmospheric CO₂ equilibrium. In the total 30 rain events, only two events were observed in acidic range (< 5.6) which occurred after continuous rains. The equivalent concentration of components followed the order: Ca²⁺ > SO₄ ²⁻ > NH₄ ⁺ > NO₃ ⁻ > Na⁺ > K⁺ > H⁺. The volume-weighted mean (VWM) of the measured ionic sum is 371.62 μeq/l. The ratio of between sum cations and sum anions (∑cations /∑ anions) is 1.52 μeq/l. The alkaline components (Ca²⁺, Na⁺, K⁺) contribute 52%, NH₄ ⁺ 8%, whereas, the contribution from the acidic components is relatively small (40%). The low concentrations of H⁺ found in rainwater samples from Mugla suggest that an important portion of H₂SO₄ and HNO₃ have been neutralized by alkaline particles in the atmosphere. The dust-rich local and surrounding limestone environment might have caused the high concentration of Ca²⁺ in Mugla area. The relatively high concentration of NH₄ ⁺ observed at Mugla is suspected to be due to surrounding agricultural. The results obtained in this study are compared with those other studies conducted at various places in the world.     

Estimated Variability of National Atmospheric Deposition Program/Mercury Deposition Network Measurements Using Collocated Samplers

The National Atmospheric Deposition Program/Mercury Deposition Network (MDN) provides long-term, quality-assured records of mercury in wet deposition in the USA and Canada. Interpretation of spatial and temporal trends in the MDN data requires quantification of the variability of the MDN measurements. Variability is quantified for MDN data from collocated samplers at MDN sites in two states, one in Illinois and one in Washington. Median absolute differences in the collocated sampler data for total mercury concentration are approximately 11% of the median mercury concentration for all valid 1999–2004 MDN data. Median absolute differences are between 3.0% and 14% of the median MDN value for collector catch (sample volume) and between 6.0% and 15% of the median MDN value for mercury wet deposition. The overall measurement errors are sufficiently low to resolve between NADP/MDN measurements by ±2 ng·l⁻¹ and ±2 μg·m⁻²·year⁻¹, which are the contour intervals used to display the data on NADP isopleths maps for concentration and deposition, respectively.     

Three-year monitoring results of nitrate and ammonium wet deposition in Thailand

Wet deposition is one of the important sources of nitrogen input into the ecosystem. It also contributes to rain acidity in some environments. In this study we reported the annual as well as seasonal trends of nitrogen wet deposition at three locations in Thailand: Bangkok, Chiang Mai and Nan. Comparison of nitrogen wet deposition between in rural and in the urban areas was also made. Daily rainfall was measured and monthly rainwater was collected for nitrogen analysis during 1999–2002. The average NO₃ ^– concentration in rainwater collected from the rural sites (60 km from urban area) was around 0.2–0.3 mg L^–1, while that from the urban areas of Chiang Mai and Nan cities it was 0.4–0.5 mg L^–1. NH₄ ⁺ concentration in rainwater showed the similar ranges to that of NO₃ ^– , except at Nan where concentration was not significantly different between the urban and rural sites. On the other hand, the average concentrations of NO₃ ^– were higher at Bangkok site than other sites, while concentration of NH₄ ⁺ was almost the same between Chiang Mai and Bangkok. Wet deposition of NO₃ ^– at the rural sites of Chiang Mai and Nan ranged from 2.1 to 3.2 kg N ha^–1 yr^–1, while at the urban sites this ranged from about 6 kg N ha^–1 yr^–1 in Chiang Mai and Nan Cities to 8.6 kg N ha^–1 yr^–1 in Bangkok. Wet deposition of NH₄ ⁺ at the rural sites of Chiang Mai and Nan was about 2.4 to 3.6 kg N ha^–1 yr^–1 and at the urban sites of Chiang Mai, Nan and Bangkok this was 7.7, 4.9 and 8.1 kg N ha^–1 yr^–1, respectively. Thus, it was concluded that wet deposition of both nitrogen species was significantly higher at the urban sites than at the rural sites.     

Water quality assessment: surface water sources used for drinking and irrigation in Zaria,Nigeria are a public health hazard

We assessed the quality and pollution status of source surface waters in Zaria, Nigeria by monitoring the nature, cause and extent of pollution in Samaru stream, Kubanni River and Kubanni dam over a period of 10 months, between March and December 2002. A total of 228 water samples was collected from 12 sites and analysed for a total of ten physicochemical and one bacteriological quality indicators, using standard methods. Aesthetic water quality impairment parameters were also observed. The mean values of most water quality parameters were significantly higher (P < 0.05) in both the stream and river than in the dam. There was no significant correlation between faecal coliform counts (FCC) and water temperature (in the range 15–33°C); pH (5.77–7.32); and turbidity (1.4–567 NTU). The high FCC ranged from 2.0 × 10¹ to 1.6 × 10⁶ MPN/100 ml and exceeded the WHO standards for drinking water and water used for fresh-produce irrigation, and correlated positively (P < 0.05) with conductivity (in the range 68–1,029 μS/cm); TDS (10.0–70.0 mg/l); TSS (10.0–70.0 mg/l); Cl (7.5–181 mg/l); PO₄⁻P (0.01–0.41 mg/l); NO₃⁻N (0.6–3.8 mg/l) and BOD₅ (0.1–14.9 mg/l). The main pollution sources were municipal wastewater, stormwater runoffs, the ABU sewage treatment plant, abattoir effluents and irrigation farms treated with chemical fertilisers. We conclude that these water bodies are potentially hazardous to public health and that proper sewage treatment and river quality monitoring are needed to warn against hazards to public health.     

Application of a Larval Medaka Assay to Evaluate the Fish Safety Level in Sagami River, Japan

Physico-chemical characteristics of some river and hand-dug well waters used for drinking and domestic purposes in the oil rich Niger Delta area of Nigeria were assessed using standard methods. The concentrations of the parameters in the river water samples ranged in the following order: pH (5.6–6.9), temperature (26.90–28.60°C), turbidity (23–63 NTU), electrical conductivity (52–184 μs/cm), DO (5.4–7.2 mg/l), BOD (21–57 mg/l), TDS (6.0–217 mg/l), PO₄ ³⁻ (0.19–1.72 mg/l), SO₄ ²⁻ (25–36.8 mg/l), NO₃ ⁻ (20.3–28 mg/l), Fe (6.07–15.71 mg/l), Zn (0.04–0.24 mg/l), Pb (0.01–0.17 mg/l), Ni (0.01–0.13 mg/l), Vn (0.01–0.20 mg/l) and Hg (0.001–0.002 mg/l). The concentrations of these parameters in the hand-dug well water ranged in the following order: pH (5.7–6.8) temperature (26–30°C), turbidity (134–171 NTU), electrical conductivity (160–340 μs/cm), DO (5.4–6.4 mg/l), BOD (13–34 mg/l), TDS (110–190 mg/l), PO₄ ³⁻ (0.84–1.84 mg/l), SO₄ ²⁻ (10.6–28.1 mg/l), NO₃ ⁻ (11.3–23 mg/l), Fe (13.17–16.31 mg/l), Ni (0.01–0.02 mg/l), Vn (0.01–0.04 mg/l) and Hg (0.001–0.004 mg/l). The concentrations of BOD, turbidity, NO₃ ⁻ and Fe in the water samples were above WHO and FMENV permissible limits for safe drinking water. The results suggest that the use of such waters for drinking and domestic purposes pose a serious threat to the health of the users and calls for the intervention of government agencies.     

Radiocaesium Activity Concentrations in Wheat Grains in the Republic of Croatia for 1965–2003 and Dose Assessment

Results of systematic, long-term measurements of ¹³⁷Cs activities in wheat for the period 1965–2003 are summarized. Radiocaesum fallout activities affect wheat activity concentrations, the coefficient of correlation being 0.91. In the observed period, the highest activity of ¹³⁷Cs deposited by fallout, 6321 Bq m⁻², was recorded in 1986, i.e., in the year of Chernobyl accident, causing peak ¹³⁷Cs activity concentration in wheat of 38.0 ± 13.0 Bq kg⁻¹. After the Chernobyl nuclear accident the ¹³⁴Cs:¹³⁷Cs activity ratio in wheat was ≈0.5, and did not differ from the value found in other environmental samples. The transfer coefficient from ¹³⁷Cs fallout deposition to wheat was calculated to be 8.6 × 10⁻³ Bq y kg⁻¹ per Bq m⁻², indicating the low transfer of radiocaesium from fallout to wheat. The upper limit for the collective effective dose for the Croatian population due to ¹³⁷Cs and ¹³⁴Cs ingestion by wheat and wheat products consumption for period 1965–2003 was estimated to be 665 person-Sv, the upper limit for the annual collective effective dose in 2003 being only about 0.061 person-Sv.     

Greenhouse gas mitigation in rice–wheat system with leaf color chart-based urea application

Conventional blanket application of nitrogen (N) fertilizer results in more loss of N from soil system and emission of nitrous oxide, a greenhouse gas (GHG). The leaf color chart (LCC) can be used for real-time N management and synchronizing N application with crop demand to reduce GHG emission. A 1-year study was carried out to evaluate the impact of conventional and LCC-based urea application on emission of nitrous oxide, methane, and carbon dioxide in a rice–wheat system of the Indo-Gangetic Plains of India. Treatments consisted of LCC scores of ≤4 and 5 for rice and wheat and were compared with conventional fixed-time N splitting schedule. The LCC-based urea application reduced nitrous oxide emission in rice and wheat. Application of 120 kg N per hectare at LCC ≤ 4 decreased nitrous oxide emission by 16% and methane by 11% over the conventional split application of urea in rice. However, application of N at LCC ≤ 5 increased nitrous oxide emission by 11% over the LCC ≤ 4 treatment in rice. Wheat reduction of nitrous oxide at LCC ≤ 4 was 18% as compared to the conventional method. Application of LCC-based N did not affect carbon dioxide emission from soil in rice and wheat. The global warming potential (GWP) were 12,395 and 13,692 kg CO₂ ha⁻¹ in LCC ≤ 4 and conventional urea application, respectively. Total carbon fixed in conventional urea application in rice–wheat system was 4.89 Mg C ha⁻¹ and it increased to 5.54 Mg C ha⁻¹ in LCC-based urea application (LCC ≤ 4). The study showed that LCC-based urea application can reduce GWP of a rice–wheat system by 10.5%.     

Cyanobacterial Flora from Polluted Marine Shores

Citation of cyanobacterial cultures from the shores of south west coast of Gujarat, India and their relationship with sea water quality, influenced by extensive pollutant runoff is reported in this study. Intensity of pollution was evaluated by physico-chemical analysis of water. Higher load of suspended solids (60–1000 mg l⁻¹) and nutrients (PO₄ ⁻P: 1.3–4 μmole l⁻¹ and NO₃ ⁻N: 12.5–17.8 μmole l⁻¹) were persistent throughout the analysis. Community structure is seen to be influenced by such persistent pollution. Twenty nine cyanobacterial species were isolated belonging to 9 genera of 4 families, with an elevated occurrence of Oscillatoria and Lyngbya species. No heterocystous cyanobacteria were isolated throughout the study.