Trends of Contaminants and Effects in Bald Eagles of the Great Lakes Basin

Bald eagle (Haliaeetus leucocephalus) numbers in North America have increased since the ban of DDT and other organochlorine compounds in the 1970s. The decrease in the environmental concentrations of p,p-DDE has lead to the lessening of egg-shell thinning and has been a major reason for the current resurgence of bald eagle populations in temperate North America, however, this recovery has not been uniform. Eagles nesting along the shorelines and islands of the Great Lakes have continued to experience impaired productivity. In order to examine some of the reasons for the current recovery of bald eagles in the Great Lakes Basin and the potential use of eagles as a bioindicator species of Great Lakes water quality, we analyzed trends in reproductive activity, concentrations of PCBs and p,p-DDE in unhatched eggs, and rates of developmental deformities. Numbers of occupied nests, fledged young, and yearly productivity rates have increased across the basin. No trends have been observed in changes in the concentrations of p,p-DDE nor Total PCBs in unhatched eggs. An increasing rate in the incidence of developmental deformities in nestlings has been observed in Michigan. The recovery of the bald eagle population along the Great Lakes is most likely due to immigration of relatively uncontaminated adults from Interior regions.     

Monitoring the Elimination of Persistent Toxic Substances from the Great Lakes; Chemical and Physiological Evidence from Adult Herring Gulls

To assess progress towards virtual elimination of PCBs, DDE, dieldrin and Mirex and their associated physiological effects, we compared their concentrations in pooled livers of adult herring gulls (Larus argentatus) repeatedly sampled at 8 Great Lakes colonies and a reference colony on the Atlantic coast between 1974 and 1993. We measured the relative thyroid mass and concentrations of highly carboxylated porphyrins and retinyl palmitate in the liver of each individual. PCBs, dieldrin and mirex declined in 7 of 8 colonies while DDE decreased in six. The greatest decreases occurred pre-1985. PCBs and DDE did not decrease in gulls from Middle Island in western L. Erie. Middle Island and Saginaw Bay had the highest concentrations of PCBs of 11 Great Lakes colonies in the 1990s. Thyroids of gulls from Great Lakes colonies were slightly enlarged but the degree of enlargement has decreased over time. In 1991, gulls from Great Lakes colonies had slight to moderately elevated concentrations of highly carboxylated porphyrins. In the early 1990s, hepatic stores of retinyl palmitate were very seriously depleted in gulls from the Detroit River, western basin of Lake Erie, and Lake Ontario, reflecting decreased availability and altered storage. We conclude that PCBs and/or other persistent toxic substances in the food of herring gulls have not been virtually eliminated.     

Spatial and Temporal Trends in Organochlorine Contamination and Bill Deformities in Double-Crested Cormorants (Phalacrocorax Auritus) from the Canadian Great Lakes

The levels of organochlorine contaminants (OCs) in the eggs of double-crested cormorants (Phalacrocorax auritus) from the Canadian Great Lakes, Lake Nipigon and Lake-of-the-Woods were monitored between 1970 and 1995. PCBs and p,p-DDE were present at the highest concentrations. Significant declines in OC concentrations on the Great Lakes were observed over this period for Lake Ontario, Lake Superior, Georgian Bay and North Channel but not Lake Erie where levels remained relatively stable. In the early 1970s, the greatest OC levels were generally observed in cormorant eggs from nesting sites in Georgian Bay and North Channel of Lake Huron. Between 1984 and 1995 mirex and PCB levels were consistently highest in samples from Lakes Ontario and Erie, respectively. Similar levels of PCDDs and PCDFs were observed from all regions of the Canadian Great Lakes in 1989. In general, OC levels in cormorant eggs between 1984-95 were ranked as follows: Lake Erie>Lake Ontario Lake Superior>Lake Huron. In 1995, eggshell thickness in Canadian Great Lakes cormorants, ranged from 0.423 to 0.440 mm and was on average only 2.3% thinner than pre-DDT era values. Between 1988 and 1996, 31 cormorant chicks with bill defects were observed at 16 different colonies (21% of all colonies surveyed) in Lakes Ontario and Superior, Georgian Bay and North Channel, and the main body of Lake Huron. No bill deformities were observed at reference sites in northwestern Ontario (Lake Nipigon and Lake-of-the-Woods). For the period 1988-96, the prevalence of bill defects in cormorant chicks (0.0 to 2.8/10,000 chicks) did not differ significantly (P > 0.05) among most regions in the Canadian Great Lakes. Georgian Bay was the only region to show a significant decrease in the prevalence of bill defects between the periods 1979-87 and 1988-95.     

Reproductive and Physiological Effects of Environmental Contaminants in Fish-Eating Birds of the Great Lakes: A Review of Historical Trends

During the 1950s and 1960s, reproductive failures and population declines were observed in fish-eating birds such as gulls, terns, cormorants, herons, and eagles in the Great Lakes. DDE-induced eggshell thinning contributed to these declines, but other factors such as embryo toxicity also were implicated. With reduced releases of many pollutants, reproduction recovered in some species. However, biomonitoring during the 1980s and 1990s indicates continuing effects at highly contaminated sites. Improved analytical techniques and bioassays have allowed the assessment of the total dioxin-like toxicity of complex mixtures of organochlorines (TCDD-equivalents). Developmental defects such as embryo mortality, deformities, and edema have been associated with dioxin-like PCBs in several avian species. Improved biochemical techniques have allowed the measurement of biomarkers that detect physiological alterations associated with contaminants. Specific biomarkers studied in Great Lakes birds include cytochrome P-450 monooxygenases, highly carboxylated porphyrins, thyroxine, vitamin A, and immune function. Reproductive and physiological alterations are associated with population-level effects in Caspian terns and bald eagles that feed on highly contaminated fish. Biomonitoring using biomarkers and population-level measures in fish-eating birds will continue to be important for assessing the effects of contaminants on the Great Lakes ecosystem.     

Trends in Concentrations and Effects of Persistent Toxic Contaminants in the Great Lakes: Their Significance for Inferring Cause-Effect Relationships and Validating Management Actions

This paper summarizes a workshop on temporal trends in levels and effects of persistent toxic contaminants in the North American Great Lakes. Information on trends in contaminant levels is reasonably good for sediments, fish, and birds, but is scanty or absent for other ecosystem components. Information on trends in effects has been reported for birds, but is scanty or absent for other groups of organisms. In principle, information on differential trends in effects of contaminants could be used to validate or improve hypotheses about cause-effect relationships and to verify the effectiveness of management actions. However, little or no useful information on differential trends appears to be available. Use of trend data for these purposes will require collection of more detailed information and greater attention to conceptual formulation of hypotheses.     

Metals in Herring and Great Black-Backed Gulls from the New York Bight: the Role of Salt Gland in Excretion

We examined the tissue distribution ofmetals in the herring (Larus argentatus) andgreat black-backed (Larus marinus) gullsobtained near the John F. Kennedy Airport, on LongIsland, New York, to determine whether there werespecies differences and whether levels in the saltgland were sufficiently high to suggest that thisorgan may be serving an excretory function. For mostorgans, herring gulls had significantly higher levelsof lead (except for liver), but significantly lowerlevels of mercury (except in the salt gland) thangreat black-backed gulls. For all metals exceptarsenic, there were significant differences inconcentrations among tissues for both species. Greatblack-backed gulls had much higher concentrations ofcadmium in kidney than in any other organ and this wasmuch higher than the level in herring gulls; herringgulls had much higher levels than black-backs of leadin salt glands. For both species, concentrations inkidney, liver and salt gland were generally higherthan in heart muscle or pectoral muscle. For herringgulls, the concentrations of all metals in the saltglands were not significantly different from the organwith the highest values (liver or kidney). For greatblack-backed gulls this was true only for lead,selenium, chromium, and mercury. We examined theratio of metals in all organs to the liverconcentration. Very low ratios (<0.25) were foundfor lead in heart and muscle of both species, andselenium in heart and muscle of herring gulls. Highratios (>2) included lead (2.75:1) and cadmium(14.3:1) in kidney of black-backs. In greatblack-backs the kidney:salt gland ratio was >1.5:1except for mercury (1.31:1) and chromium (0.83:1),while in herring gulls all ratios were between 0.7 and1.2, except for mercury (0.46:1), reflecting therelatively higher concentrations of metals in the saltgland of this species. We suggest that most heavymetals seem to be concentrating in the salt glands ofgulls, within an order of magnitude of the kidneyconcentration, and that salt glands may be serving asignificant excretory function for these cations.     

Twenty years of temporal change in perfluoroalkyl sulfonate and carboxylate contaminants in herring gull eggs from the Laurentian Great Lakes

In this study, temporal trends and patterns of major C(4) to C(15) chain length PFCAs and PFSAs and some sulfonamide, fluorotelomer acid and alcohol precursors were determined in herring gull (Larus argentatus) egg pools. Samples were analyzed from fifteen collection years including 1990 and all years from 1997 to 2010, and from seven colonies located throughout the Great Lakes, ranging from remote to highly urbanized areas. Other than at the Toronto Harbour colony, the slopes of ∑PFSA concentrations (C(6), C(8), and C(10)) versus time were negative indicating general declines between 1990 and 2010. PFOS was the dominant PFSA regardless of colony or year, ranging from 80 to 99% of ∑PFSA. For ∑PFCA (C(8)-C(15)), slopes of concentrations versus time were generally positive with 4 of 7 colonies showing statistically significant (p < 0.05) increases in levels through time. Individual PFCAs showed similar increasing trends except for PFOA. Regardless of colony, the PFCA pattern was dominated by the C(10) to C(13) PFCAs. Consistent with the PFOS declines, concentrations of the PFOS precursor, PFOSA, declined at most colonies between 1990 and 2006 and post-2006 concentrations were below detection limits. Declining concentrations of the C(8) PFCs, PFOS, PFOA and PFOSA, were consistent with the phase out in 2002 by the 3M Company in North America of all of C(8) PFC-related chemistry products. Increasing production volumes of fluorotelomer based compounds, and degradation of these compounds to PFCAs may explain increasing trends of PFCAs in gull eggs. Dietary changes as measured by carbon and nitrogen stable isotopes, showed minimal relationships to PFC levels in gull eggs, which indicates the complexity of aquatic and terrestrial food of gulls and sources of PFCs.     

Indices of Benthic Community Tolerance in Contaminated Great Lakes Sediments: Relations with Sediment Contaminant Concentrations, Sediment Toxicity, and the Sediment Quality Triad

We evaluated the toxic-units model developed by Wildhaber and Schmitt (1996) as a predictor of indices of mean tolerance to pollution (i.e., Lenat, 1993; Hilsenhoff, 1987) and other benthic community indices from Great Lakes sediments containing complex mixtures of environmental contaminants (e.g., polychlorinated biphenyls – PCBs, polycyclic aromatic hydrocarbons – PAHs, pesticides, chlorinated dioxins, and metals). Sediment toxic units were defined as the ratio of the estimated pore-water concentration of a contaminant to its chronic toxicity as estimated by U.S. Environmental Protection Agency Ambient Water Quality Criteria (AWQC) or other applicable standard. The total hazard of a sediment to aquatic life was assessed by summing toxic units for all contaminants quantified. Among the benthic community metrics evaluated, total toxic units were most closely correlated with Lenat's (1993) and Hilsenhoff's (1987) indices of community tolerance (T _L and T _H , respectively); toxic units accounted for 42% T _L and 53% T _H of variability in community tolerance as measured by Ponar grabs. In contrast, taxonomic richness and Shannon-Wiener diversity were not correlated (P > 0.05) with toxic units. Substitution of order- or family-level identifications for lowest possible (mostly genus- or species-) level identifications in the calculation of T _L and T _H indices weakened the relationships with toxic units. Tolerance values based on order- and family-level identifications of benthos for artificial substrate samples were more strongly correlated with toxic units than tolerance values for benthos from Ponar grabs. The ability of the toxic-units model to predict the other two components (i.e., laboratory-measured sediment toxicity and benthic community composition) of the Sediment Quality Triad (SQT) may obviate the need for the SQT in some situations.     

Survey and evaluation of contaminants in earthworms and in soils derived from dredged material at confined disposal facilities in the Great Lakes Region

Soils derived from dredged material were collected, together with earthworms from nine confined disposal facilities located in the Great Lakes Region. These samples were analyzed for 18 elements, 11 organochlorine pesticides, PCBs, and 24 polycyclic aromatic hydrocarbons. The concentrations detected in earthworms were evaluated in terms of their potential hazard to wildlife, which for the sake of the evaluation were assumed to prey entirely either on earthworms or on other soil invertebrates having similar concentrations. The soil concentrations (dry wt.) of the contaminants of greatest concern were <1.9 to 32 ppm Cd, <0.053 to 0.94 ppm Hg, 4.6 to 550 ppm Pb, and <0.1 to 1.0 ppm PCBs. The concentrations in earthworms (dry wt., ingested soil included) were as high as 91 ppm Cd, 1.6 ppm Hg, 200 ppm Pb, and 1.8 ppm PCBs. Based on laboratory toxicity studies of relatively sensitive species, and on concentration factors calculated from the earthworm and soil data, we estimated that lethal or serious sublethal effects on wildlife might be expected at concentrations of 10 ppm Cd, 3 ppm Hg, 670 ppm Pb, and 1.7 ppm PCBs in alkaline surface soils derived from dredged material. Concentrations of polycyclic aromatic hydrocarbons in earthworms were well below those in soil.     

Environmental and Biological Monitoring of Organochlorine Residues after the Plague Epidemic in Surat, India - A Preliminary Study

In late August 1994, an outbreak of human pneumonic/bubonic plague was reported in Surat, India. During the epidemic, large amounts of pesticides, such as benzene-hexachloride (BHC) and other organochlorinated compounds were used to control the vector that might have transmitted the plague. In order to evaluate the extent of contamination, both environmental samples (9 water samples and 4 soil samples) and biological samples (5 blood and urine samples) were collected and analyzed for organochlorine residues. Samples were analyzed after hexane extraction by gas chromatography equipped with electron capture detector (GC-ECD), using a PTE-5 capillary column. The results showed that the levels of 1,1-(2,2-dichloroethenylidene)-bis[4-chlorobenzene] (DDE), a major metabolite of DDT, were low in environmental samples (water, soil), while BHC levels were relatively high in one of the water sample as well as two soil samples. The BHC and DDE levels in the biological samples were not higher than those reported earlier from India, except for serum DDE. Further studies are needed to evaluate the effect of long-term exposure as the present study was based on limited samples.     

Contaminants in water, sediment and fish biomonitor species from natural and artificial estuarine habitats along the urbanized Gold Coast, Queensland

Metal and pesticide contaminants were measured in water, sediment and fish species in various Gold Coast waterways, Queensland. With the exception of Cu, metal concentrations in water, measured using the diffuse gradients in a thin film (DGT) technique, complied with relevant Australian guidelines. Cu concentrations in these waterways have been related to recreational vessel activities previously. All sediment metal concentrations measured were below the national guidelines, although Cu, Zn and Pb were found to vary significantly between habitat types. Evidence of spikes in sediment pesticide concentrations (some banned over 50 years ago) was observed in some artificial residential waterways. Heavy metals and pesticides were measured in the tissue (muscle, gills and liver) of three economically important species of fish, with different feeding strategies (partly herbivore Arrhamphus sclerolepis, carnivore Acanthopagrus australis, detritivore Mugil cephalus). We tested the hypothesis that fish accumulate different amounts of contaminants from wetland habitats affected by different intensities of anthropogenic activities (i.e., marinas, artificial residential canals, artificial residential lakes, estuaries and natural, vegetated waterways). Significantly higher concentrations of Cu were found in the gills of each fish species from marinas compared to fish caught in other waterways. Furthermore, fish caught in canals had the second highest Cu and natural waterways the lowest. These results support the stated hypothesis for Cu and furthermore indicate that these fish species are suitable as biomonitors in estuarine waterways. Metal and pesticide concentrations in the edible muscle tissue of all fish complied with the Australian Food Standard Code recommended limits for human consumption, apart from As which is likely to be due to bioconcentration of lower toxicity organo-As species. These results indicate a low health risk for humans consuming fish, in terms of contaminant levels. The accumulated body of evidence on contaminants within Gold Coast waterways generally suggests that there are no major threats of metal or pesticide contamination, except for marina facilities which are a major source of Cu which also accumulates in fish. Water quality threats are also highlighted in residential canals, presumably as a consequence of their hydrological design.     

Monitoring and Assessment of Persistent Organochlorine Residues in Sediments from the Daliaohe River Watershed, Northeast of China

Surface sediment samples from 12 sites of the three selected rivers in Daliaohe River watershed (Hunhe River, Taizihe River and Daliaohe River) were analyzed with the objective of establishing sources and hazard of the organochlorinae pesticides (OCPs) and polychlorinated biphenyl (PCBs) in surface sediments. The total concentrations of OCPs varied from 3.06 to 23.24 ng g⁻¹. ∑HCH (α-HCH, β-HCH, δ-HCH, γ-HCH), ∑DDT (p, p′-DDE, p, p′-DDD, o, p′-DDT, p, p′-DDT) and ∑Cyclodiene (Heptachlor, Aldrin, Heptachlor epoxide, Dieldrin, Endrin) ranged from 1.86 to 21.48, 0.5 to 2.81 and 0.56 to 1.53 ng g⁻¹, respectively. Results of OCPs also illustrate that the most dominant pollutants among the OCPs was ∑HCH, and γ-HCH was the most dominant isomer in HCH, which was evidence of recent input of lindane. It possibly came from the runoff of polluted soils and long-scale transportation. Total PCB concentrations ranged between 1.88 and 16.88 ng g⁻¹. The peak concentrations of PCBs were found in sediments from station T5 and D3, which are in the vicinity of industrial areas and ferry, respectively. These data show a moderate level of OCPs and PCBs contaminations compared to that in other countries.     

Progress Toward Delisting a Great Lakes Area of Concern: The Role of Integrated Research and Monitoring in the Hamilton Harbour Remedial Action Plan

The goal of restoring environmental health and qualities to Hamilton Harbour Great Lakes Area of Concern, an embayment at the western end of Lake Ontario, is considered to be achievable by the year 2015. Restoring Hamilton Harbour is a dynamic process that relies heavily on research and monitoring to direct remediation efforts. Three principle means of coordinating this research and monitoring include: research and monitoring workshops; a monitoring catalogue outlining both government and nongovernment initiatives; and an annual report written by a local community group. These tools increase the effectiveness of remedial actions by: (i) improving stakeholders' ability to track trends; (ii) allowing program decision-makers to utilize adaptive management techniques to continuously modify programs based on new results; (iii) integrating interdisciplinary fields, and (iv) increasing accountability. This paper describes in detail these tools used for coordinating research and monitoring in implementing the Remedial Action Plan of the Hamilton Harbour Great Lakes Area of Concern, along with lessons learned to assist other implementers who are considering similar programs.     

Concentrations of Arsenic, Cadmium, Copper, Lead, Selenium, and Zinc in Fish from the Mississippi River Basin, 1995

Fish were collected in late 1995 from 34 National Contaminant Biomonitoring Program (NCBP) stations and 12 National Water Quality Assessment Program (NAWQA) stations in the Mississippi River basin (MRB), and in late 1996 from a reference site in West Virginia. The NCBP sites represented key points (dams, tributaries, etc.) in the largest rivers of the MRB. The NAWQA sites were typically on smaller rivers and were selected to represent dominant land uses in their watersheds. The West Virginia site, which is in an Eastern U.S. watershed adjacent to the MRB, was selected to document elemental concentrations in fish used for other aspects of a larger study and to provide additional contemporaneous data on background elemental concentrations. At each site four samples, each comprising (nominally) 10 adult common carp (Cyprinus carpio, 'carp') or black bass (Micropterus spp., 'bass') of the same sex, were collected. The whole fish were composited by station, species, and gender for analysis of arsenic (As), lead (Pb), and selenium (Se) by atomic absorption spectroscopy and for cadmium (Cd), copper (Cu), and zinc (Zn) by inductively-coupled plasma emission spectroscopy. Concentrations of most of the elements examined were lower in both carp and bass from the reference site, a small impoundment located in a rural area, than from the NCBP and NAWQA sites on rivers and larger impoundments. In contrast, there were few overall differences between NCBP sites NAWQA sites. The 1995 results generally confirmed the continued weathering and re-distribution of these elemental contaminants in the MRB; concentrations declined or were unchanged from 1984-1986 to 1995 at most NCBP sites, thus continuing two-decade trends. Exceptions were Se at Station 77 (Arkansas R. at John Martin Reservoir, CO), where concentrations have been elevated historically and increased slightly (to 3.8-4.7 microg g-(1) in bass and carp); and Pb, Cd, and Zn at Station 67 (Allegheny R. at Natrona, PA), where levels of these metals were high in the past and increased from 1986 to 1995.     

Reduced Metals Concentrations of Water, Sediment and Hyalella Azteca from Lakes in the Vicinity of the Sudbury Metal Smelters, Ontario, Canada

Hyalella azteca (Crustacea: Amphipoda), water and sediments from 12 circum-neutral lakes between Sudbury and North Bay in Ontario, Canada were sampled in August 1998 and analyzed for 10 metals including Cu, Zn, Cd, Ni, Pb, Co, Mo, V, Ba and Ti. Statistical analyses showed that concentrations of the metals in H. azteca, water and sediment differed significantly (ANOVA, P<0.05) among lakes (except for Zn and Pb in H. azteca and Mo in water). There was a trend of declining metal concentration, especially for Cu, Ni and Co (in water, Hyalella and sediment), with distance from the smelters indicating the reduced impact of atmospheric pollution. Metal concentrations of lakes (water) in the Sudbury area were found to be lower compared to data from the 1970s and 1980s indicating an improvement in water quality. Metal concentrations in field-collected amphipods compared favorably with those measured in the laboratory in animals exposed to deep-water sediments, provided metal concentrations were not extremely low (e.g., Pb) and that water chemistry differences (e.g., pH) were taken into account for some metals (especially Cd). In general bioaccumulation of metals in H. azteca was predicted better from surface water than from sediment total metal.     

Organochlorine pesticides and polychlorinated biphenyl residues in reared and wild Dicentrarchus labrax from the Mediterranean Sea (Sicily, Italy)

The aim of this research was to compare the levels of organochlorine pesticides and PCBs in samples of Dicentrarchus labrax living in the Straits of Messina with samples cultivated in cages in the Mediterranean Sea. Muscles and liver tissues sampled over the months, within the same year, were analyzed. The quantitative determination of the organochlorine compounds was performed by GC-ECD and confirmed with GC–MS. The results showed that the concentrations of DDTs in muscles and livers as such of reared sea bass were in the range 0.2–1.3 μg/kg and 9.6 –48.4 μg/kg, respectively. In wild fish the concentrations of DDTs were very much lower: 0.1 μg/kg in muscles, 5.1–9.0 μg/kg in livers. Total PCBs levels were higher in cultivated sea bass than in wild fish; the concentration ranges were 5.3–59.7 μg/kg and 74.4–267.4 μg/kg in muscle and liver of reared samples, respectively, and 1.1–1.5 μg/kg and 63.2–109.4 μg/kg in muscle and liver of wild samples, respectively.     

Organochlorine pesticides in the surface water and sediments from the Peacock River Drainage Basin in Xinjiang, China: a study of an arid zone in Central Asia

Fourteen surface water and nine surface sediment samples were collected from the Peacock River and analyzed for organochlorine pesticides (OCPs) by gas chromatograph?Celectron capture detector (GC-ECD). All the analyzed organochlorine pesticides, except o,p ^??-DDT, were detected in sediments from the Peacock River; but in the water samples, only ??-HCH, HCB, p,p ^??-DDD, and p,p ^??-DDT were detected at some sites. The ranges for total OCPs in the water and sediments were from N.D. to 195 ng l^???1 and from 1.36 to 24.60 ng g^???1, respectively. The only existing HCH isomer in the water, ??-HCH, suggested that the contamination by HCHs could be attributed to erosion of the weathered agricultural soils containing HCHs compounds. Composition analyses showed that no technical HCH, technical DDT, technical chlordanes, endosulfans, and HCB had been recently used in this region. However, there was new input of ??-HCH (lindane) into the Peacock River. The most probable source was water flowing from Bosten Lake and/or agricultural tailing water that was returned directly into the Peacock River. DDT compounds in the sediments may be derived mainly from DDT-treated aged and weathered agricultural soils, the degradation condition was aerobic and the main product was DDE. HCB in the sediment might be due to the input from Bosten Lake and the lake may act as an atmospheric deposition zone. There was no significant correlation between the concentrations of OCPs (including ??HCH, ??DDT, chlordanes, endosulfans, HCB and total OCPs) and the content of fine particles (<63 ??m). The concentrations of OCPs were affected by salinity.     

Change in drinking water quality from source to point-of-use and storage: a case study from Guwahati, India

To ascertain the quality of drinking water being supplied and maintained at Guwahati, the study was conducted on the status of water supply in city through surveillance of drinking water quality for consecutive 7 days at various treatment stages, distribution network and consumer ends. The performance of five water treatment plants (WTPs), viz. Panbazar WTP, Satpukhuri WTP, Kamakhya WTP, PHED WTP and Hegrabari WTP were assessed for summer, piost-post-monsoon and winter seasons. No significant change in raw water quality was observed on day-to-day basis. Residual chlorine was found in the range of nil to 0.2 mg/L in the treated water. During post-monsoon, winter, and summer seasons the thermotolerent TC and FC counts ranged between Nil to 168 CFU/100 ml and Nil to 84 CFU/100 ml; Nil to 3356 CFU/100 ml and Nil to 152 CFU/100 ml; and Nil to 960 CFU/100 ml and Nil to 108 CFU/100 ml respectively. There was variation in bacterial counts among the different service reservoirs and consumer ends, which may be attributed to the general management practices for maintenance of service reservoirs and the possibility of enroute contamination. Evaluation of the raw water quality indicate that the water is suitable for drinking after conventional treatment followed by disinfection. The finished water quality meets the level of standards described as per Bureau of Indian Standard specifications (BIS:10500 1991) for potability in terms of its physico-chemical characteristics.     

Analysis of diazinon monitoring data from the Sacramento and Feather River watersheds: 1991-2001

The objectives of this study were to: (1) analyzehistorical diazinon water column monitoring data frominconsistent monitoring programs in mainstem and tributary sitesin the Sacramento and Feather River watersheds from 1991 to 2001to assess possible spatial and temporal trends and (2) determinethe probability of measured diazinon concentrations by site orsimilar pooled sites exceeding various proposed effectsbenchmarks such as Water Quality Criteria and 10th centilesderived from species sensitivity distributions proposed as targetconcentrations for Total Maximum Daily Loads (TMDLs). An analysisof diazinon monitoring data from both fixed and rain eventsampling from the Sacramento/Feather River watersheds from 1991to 2001 showed that 90th centiles for 27 different mainstemand tributary sites ranged from 12 to 14,897 ng L^-1. The 90th centiles were generally higher at tributary sites (as compared to mainstem sites) during rain event sampling prior to 1995. A comparison of rain event samples for similar sites sampled in 1994 and 2000 showed that 90th centiles were lower in seven of eight sites in 2000. A comparison of pooled mainstemsites between 1994 and 2000 for rain event data showed a lower90th centile value for 2000; 90th centiles were alsolower in 2000 at all pooled tributary sites and all sites whendata from a highly influential site was removed. For varioussite designations (all sites, pooled mainstem sites etc.) theprobability of exceeding the acute and chronic diazinon targetsdeveloped by California Department of Fish and Game decreasedfrom 1994 to 2000. These data clearly show progress in the 6 yrperiod in reducing environmental concentrations of diazinon.Probability of exceeding the 10th centile targets based onspecies sensitivity distributions for arthropods (the mostsensitive taxa to diazinon exposure) was similar and fairly lowbetween years; the highest percent probability of exceedance forany site designation was 20%.Results from a two-way ANOVA using individual measurementsfrom all sites sampled showed a significant decrease during rainevents between 1994 and 2000, although the decrease was notequivalent for all sites. Sources of uncertainty identified inthe analysis of rain event data from 1994 and 2000 wereinconsistent frequency of sampling during rain events for eachyear, unknown definition of rain events between the two years andnon-defined measurement point within the hydrograph of rainevents sampled in each year. Analysis of diazinon trends fromfixed sampling was limited due to lack of yearly data by site;therefore, only parametric analysis could be conducted. Based onparametric analysis of diazinon monitoring data from fixedsampling sites, the percent detected concentrations were greaterthan 20% for 12 tributary sites and 5 mainstem sites fromsamples collected during January-March. On the average over allsites and months, diazinon concentrations have decreased at fixedsampling sites in the Sacramento/Feather River watershed from1991 to 2001.     

Pesticides in rainwater in Flanders, Belgium: results from the monitoring program 1997-2001

In 1997 the Flemish Environmental Agency (FEA) started a monitoring program "Pesticides in Rain in Flanders, Belgium". The original purpose of the monitoring program was to examine the possible occurrence of dichlorvos in rainwater and subsequent deposition. However, it was thought necessary from the beginning to monitor a wide range of pesticides. During the first year some 62 pesticides and metabolites and 9 polychlorinated biphenyls, were monitored at 4 locations. Nowadays the monitoring program has grown up to more than 100 pesticides and metabolites and 11 polychlorinated biphenyls examined at 8 different locations. Rainwater is collected continuously and samples are examined for pesticides and PCB's on a weekly basis. In agreement with other European studies pesticides are found in rainwater samples during times of application. Pesticides which are most frequently detected are [small alpha]-, [small beta]-endosulfan and endosulfan sulfate, [gamma]-HCH (lindane), dichlorvos, atrazine, diuron, DNOC, glyphosate and AMPA and isoproturon. Furthermore it was seen that most pesticides showed a deposition pattern related to local spraying operations.