A survey on the temporal and spatial distribution of perchlorate in the Potomac River

Samples of river water and treated drinking water were obtained from eight sites along the Potomac River between western Maryland and Washington DC. Samples were collected each month from October 2007 to September 2008 and analyzed for perchlorate by ion chromatography/mass spectrometry. Data on anions were also collected for seven of the twelve months. Data were analyzed to identify spatial and temporal patterns for the occurrence of perchlorate in the Potomac. Over the year of sampling, the largest monthly increase occurred from June to July, with levels then decreasing from July to September. Samples from the period between December and May had lower perchlorate concentrations, relative to the remainder of the study year. Spatially, higher levels of perchlorate were found at sites located in west-central Maryland, the eastern panhandle of West Virginia, and central northern Virginia, with levels decreasing slightly as the Potomac approaches Washington DC. Within the sampling boundaries, river (untreated) water perchlorate concentrations ranged from 0.03 μg L(-1) to 7.63 μg L(-1), averaged 0.67 ± 0.97 μg L(-1) over the year-long period and had a median value of 0.37 μg L(-1). There was no evidence that any of the existing drinking water treatment technologies at the sampling sites were effective in removing perchlorate. There were no correlations found between the presence of perchlorate and any of the anions or water quality parameters examined in the source water with the exception of a weak positive correlation with water temperature. Results from the summer (June-August) and fall (September-November) months sampled in this study were generally higher than from the winter and spring months (December-May). All but one of the locations had annual average perchlorate levels below 1 μg L(-1); however, 7 of the 8 sites sampled had river water perchlorate detections over 1 μg L(-1) and 5 of the 8 sites had treated water detections over this level.     

Characteristics of petroleum hydrocarbons in surficial sediments from the Songhuajiang River (China): spatial and temporal trends

This paper presents the spatial and temporal characteristics of petroleum hydrocarbons (PH) in surficial sediments from the Songhuajiang River using the method of petroleum chemical fingerprinting. Twenty-four surface sediment samples were collected at 17 sites along the river from upstream to downstream in flood season (August 2005) and icebound season (December 2005) and were analyzed for PH including n-alkanes (C(16)-C(33)), isoprenoid alkanes (pristane and phytane), and unresolved complex mixture (UCM). The concentration of PH varied from 22.64 to 91.45 μg g(?-1) dry sediment. n-alkanes with a carbon number from 16 to 33 were detected in all samples, and the UCM was the dominant composition for PH. The variability of the PH concentration was mostly influenced by external conditions, such as seasonal change and industrial area position, as well as internal sediment physicochemical properties, such as organic carbon and grain size. The concentration of hydrocarbons is higher in flood season than in icebound season and is higher upstream than downstream. The diagnostic ratios of specific hydrocarbons showed that the PH pollution comes from a combination of biogenic and petrogenic sources, and petrogenic input is dominant in icebound season relative to flood season. It also indicates that there is a clear terrigenous input of n-alkanes in flood season. Principal components analysis was used to study the composition and characteristics of PH in Songhuajiang River sediments and to assess the spatial and temporal distribution of their natural and anthropogenic sources.     

Organotins in a medium-size Mediterranean basin (the Herault River)

This study reports the first assessment of organotin pollution in the Hérault watershed, a medium size Mediterranean basin. Organotin compounds were analyzed in surface waters, wells supplying drinking water and sewage treatment plants (STPs). In surface and ground waters, a background contamination by total organotin compounds has been identified in the range of 0.51 +/- 0.02-71 +/- 2 ng(Sn) L(-1), which is of the same order of magnitude as those observed in other European areas. Organotins were systematically present in STP influents and sludge. Total or partial elimination of organotin compounds from treated wastewater was observed. STP effluents appeared nevertheless to be a non-negligible source of contamination not only of rivers but also of aquifers tapped for drinking water supply.Tributyltin concentration was higher than the maximum allowable concentration proposed by the European Commission in some surface waters and wells supplying drinking water. This could compromise the water resource and have serious and irreversible consequences for the aquatic eco-system. As it was the case for the ban of antifouling paints, a regulatory regime in decreasing point-source emissions of these harmful compounds used in household products might be applied.     

Very high concentrations of DDE and toxaphene residues in crocodiles from the Ord River, Western Australia: an investigation into possible endocrine disruption

Organochlorine pesticide concentrations, particularly those of the DDT family and of toxaphene, were measured by gas chromatography in samples of liver and body fat taken from Australian freshwater crocodiles Crocodylus johnstoni at three locations along the Ord River in Western Australia. The three sampling sites were the irrigation area, downstream of the irrigation area, and well upstream of the irrigation area; the last site serving as the control. DDT and toxaphene were applied in large and known quantities to cotton grown in the Ord Irrigation Area from 1964 to 1974. Thus the residues in the crocodile tissues are representative of the situation almost thirty years after the use of DDT and toxaphene ceased in the area. Very high concentrations of p,p'-DDE and toxaphene were found in the lipid-rich tissues that were examined. Livers and body fat from estuarine crocodiles Crocodylus porosus from the downstream site were also analysed. As p,p'-DDE and toxaphene are both known to be disruptive of endocrine systems, a range of blood parameters, including estradiol and testesterone concentrations, were also measured for all the animals studied. The ovaries and testes of the freshwater crocodiles were also examined histologically. There were no obvious effects on blood chemistry or gonad histology of the large burden of pesticides and their metabolites carried by exposed animals, although the limited number of samples and the variability of the breeding state of the animals examined may have masked possible effects. The isolation of the area, the accurately known applications of DDT and toxaphene, and the simplicity of the drainage system make the lower Ord River a unique natural laboratory for studying the long term breakdown and effects of pesticides applied in a tropical environment.     

Monitoring of pharmaceutically active compounds on the Guadalquivir River basin (Spain): occurrence and risk assessment

Guadalquivir River (South of Spain) is among the major freshwater sources of the European Atlantic basin. Until now scientific efforts have been focused on contamination by heavy metals and some priority pollutants in Guadalquivir River. However, the presence of "emerging contaminants", such as pharmaceutically active compounds, has not yet been studied. In this work the occurrence and risk assessment of sixteen pharmaceutically active compounds, belonging to different therapeutic groups, in Guadalquivir River during its course through Seville city are reported. Wastewater effluents from four wastewater treatment plants discharging into Guadalquivir River and river water samples were analyzed. All studied pharmaceutically active compounds, except sulfamethoxazole, trimethoprim, estrone and clofibric acid, were detected in effluent wastewaters at concentration levels up to 28.9 μg L(-1). Among the pharmaceutically active compounds found in effluent wastewater, seven were present in Guadalquivir River samples at concentration levels up to 0.75 μg L(-1), which indicated an important dilution from effluent discharge. Environmental risk assessment reveals that potential ecotoxicological risk cannot be expected on Guadalquivir River at measured concentration levels. Only, the lipid regulator gemfibrozil showed a medium risk for the environment. The risk for acute toxic effects in the environment with the current use of active pharmaceutical ingredients is unlikely. However, the results do not rule out the potential for chronic environmental effects.     

Determination of seventeen endocrine disruptor compounds and their spatial and seasonal distribution in Ria Formosa Lagoon (Portugal)

In spite of its outstanding ecological and touristic importance the Ria Formosa Lagoon shows signs of anthropogenic pollution. Nonetheless, until the present survey no studies had ever documented the measurement of natural and pharmaceutical estrogens (17β-estradiol, estrone, and 17α-ethynylestradiol), xenoestrogenic industrial pollutants (4-octylphenol, 4-nonylphenol, and their mono and diethoxylates and bisphenol A), phytoestrogens (formononetin, biochanin A, daidzein, genistein), and sitosterol in this area. The 17 compounds measured herein are known as endocrine disrupters (EDCs) and act over the endocrine system even in few amounts (ng L^?1–μg L^?1). Thus to conclude about the influx of EDCs in the lagoon, water samples were taken every 2 months, during 1 year (2010), in low tide at nine sites distributed along the coastline. Water samples (1 L) were preconcentrated in the Oasis HLB cartridges and cleaned in silica cartridges before their analysis by GC-MS. Data showed the ubiquitous presence of potentially hazardous amounts of estrogens (particularly of ethynylestradiol, up to 24.3 ng L^?1), nonylphenol (up to 547 ng L^?1), and sitosterol (up to 12,300 ng L^?1), mainly in summer, suggesting that the increase of the local number of inhabitants (tourists), the rise of the water temperature (up to 26 °C), and the blooming of local flora may interfere with the water quality parameters. This makes the lagoon a potential model to study. Taking into account the data, it was concluded that there are conditions for the occurrence of endocrine disruption in aquatic animals, even in areas included in the natural park of the Formosa. Besides, both the high amounts of un-ionized ammonia (up to 0.3 mg L^?1) and phosphates (up to 1.6 mg L^?1) my pose risks for local fauna and humans.     

Fish abundances in shoreline habitats and submerged aquatic vegetation in a tidal freshwater embayment of the Potomac River

Submerged aquatic vegetation (SAV) is considered an important habitat for juvenile and small forage fish species, but many long-term recruitment surveys do not effectively monitor fish communities in SAV. To better understand the impact of recent large increases of SAV on the fish community in tidal freshwater reaches of the Potomac River, we compared traditional seine sampling from shore with drop ring sampling of SAV beds (primarily Hydrilla) in a shallow water (depths, <1.5 m) embayment, Gunston Cove. To accomplish this, we developed species-specific catch efficiency values for the seine gear and calculated area-based density in both shoreline and SAV habitats in late summer of three different years (2007, 2008, and 2009). For the dominant species (Fundulus diaphanus, Lepomis macrochirus, Etheostoma olmstedi, Morone americana, Lepomis gibbosus, and Fundulus heteroclitus), density was nearly always higher in SAV, but overall, species richness was highest in shoreline habitats sampled with seines. Although historical monitoring of fish in Gunston Cove (and throughout Chesapeake Bay) is based upon seine sampling (and trawl sampling in deeper areas), the high densities of fish and larger areal extent of SAV indicated that complementary sampling of SAV habitats would produce more accurate trends in abundances of common species. Because drop ring samples cover much less area than seines and may miss rare species, a combination of methods that includes seine sampling is needed for biodiversity assessment. The resurgence of SAV in tidal freshwater signifies improving water quality, and methods we evaluated here support improved inferences about population trends and fish community structure as indicators of ecosystem condition.     

Toxicity of sediment pore water in Puget Sound (Washington, USA): a review of spatial status and temporal trends

Data from toxicity tests of the pore water extracted from Puget Sound sediments were compiled from surveys conducted from 1997 to 2009. Tests were performed on 664 samples collected throughout all of the eight monitoring regions in the Sound, an area encompassing 2,294.1 km². Tests were performed with the gametes of the Pacific purple sea urchin, Strongylocentrotus purpuratus, to measure percent fertilization success as an indicator of relative sediment quality. Data were evaluated to determine the incidence, degree of response, geographic patterns, spatial extent, and temporal changes in toxicity. This is the first survey of this kind and magnitude in Puget Sound. In the initial round of surveys of the eight regions, 40 of 381 samples were toxic for an incidence of 10.5 %. Stations classified as toxic represented an estimated total of 107.1 km², equivalent to 4.7 % of the total area. Percent sea urchin fertilization ranged from >100 % of the nontoxic, negative controls to 0 %. Toxicity was most prevalent and pervasive in the industrialized harbors and lowest in the deep basins. Conditions were intermediate in deep-water passages, urban bays, and rural bays. A second round of testing in four regions and three selected urban bays was completed 5–10 years following the first round. The incidence and spatial extent of toxicity decreased in two of the regions and two of the bays and increased in the other two regions and the third bay; however, only the latter change was statistically significant. Both the incidence and spatial extent of toxicity were lower in the Sound than in most other US estuaries and marine bays.     

The effects of hydraulic works and wetlands function in the Salado-River basin (Buenos Aires,Argentina)

Man-made activities exert great influences on fluvial ecosystems, with lowland rivers being substantially modified through agricultural land use and populations. The recent construction of drainage canals in the upper stretch of the Salado-River basin caused the mobilization of huge amounts of salts formerly stored in the groundwater. The main aim of this work was to analyze the effect of the discharges of those canals into the Salado-River water, under different hydrologic conditions, and the role of the wetlands and shallow lakes placed along the canals’ system. Physicochemical variables were measured and water samples were taken during times of high water, mean flows, drought, and extreme drought. The environmental variables and the plankton development were related to the hydrologic regime and reached minimum values during floods because of low temperatures and dilution. Local effects on the water’s ionic composition became pronounced during droughts because of groundwater input. Nutrient concentrations were mainly associated with point wastewater discharges. Conductivity, ion concentrations, total plankton biomass, and species richness increased in the Salado-River downstream site, after the canals’ discharges. The artificial-drainage system definitely promotes the incorporation of salts into the Salado-River basin. In this scenario, a careful hydraulic management is needed to take into account this issue of secondary salinization that threatens the economic exploitation of the region. The wetlands present in this study acted as service environments not only helping to reduce salt, nutrient, and suspended-solid concentrations downstream but also contributing a plethora of species and plankton biomass into the Salado-River main course.     

Use of biological indicators to assess water quality of the Ul River (Portugal)

Diatoms and macroinvertebrates have been extensively used as water quality indicators in Europe for the last two decades. In Portugal, the use of biological indicators to assess water quality in rivers has increased greatly. The aim of this work was to assess the water quality and ecological status of the Ul River in order to evaluate its ability for the establishment of a fluvial beach, using periphytic diatoms and macroinvertebrates as indicators. Four sites were selected along the Ul River. At each site, biological, physical, and chemical parameters were investigated. Epilithic diatoms and macroinvertebrates were sampled. The Specific Polluosensitivity Index and the Biological Diatom Index were applied to diatom data, while for macroinvertebrates, the Iberian Biological Monitoring Working Party (IBMWP) was used. According to the results obtained, it was possible to conclude that up to now, this river does not possess the ideal conditions for the establishment of a fluvial beach. We concluded that epilithic diatoms and macroinvertebrates provided consistent information on water quality assessment and can be used as biological indicators of the water quality in Ul River.     

Spatial and seasonal patterns in water quality in an embayment-mainstem reach of the tidal freshwater Potomac River, USA: a multiyear study

Spatial and temporal patterns in water quality were studied for seven years within an embayment-river mainstem area of the tidal freshwater Potomac River. The purpose of this paper is to determine the important components of spatial and temporal variation in water quality in this study area to facilitate an understanding of management impacts and allow the most effective use of future monitoring resources. The study area received treated sewage effluent and freshwater inflow from direct tributary inputs into the shallow embayment as well as upriver sources in the mainstem. Depth variations were determined to be detectable, but minimal due mainly to the influence of tidal mixing. Results of principal component analysis of two independent water quality datasets revealed clear spatial and seasonal patterns. Interannual variation was generally minimal despite substantial variations in tributary and mainstem discharge among years. Since both spatial and seasonal components were important, data were segmented by season to best determine the spatial pattern. A clear difference was found between a set of stations located within one embayment (Gunston Cove) and a second set in the nearby Potomac mainstem. Parameters most highly correlated with differences were those typically associated with higher densities of phytoplankton: chlorophyll a, photosynthetic rate, pH, dissolved oxygen, BOD, total phosphorus and Secchi depth. These differences and their consistency indicated two distinct water masses: one in the cove harboring higher algal density and activity and a second in the river with lower phytoplankton activity. A second embayment not receiving sewage effluent generally had an intermediate position. While this was the most consistent spatial pattern, there were two others of a secondary nature. Stations closer to the effluent inputs in the embayment sometimes grouped separately due to elevated ammonia and chloride. Stations closer to tributary inflows into the embayment sometimes grouped separately due to dilution with freshwater runoff. Segmenting the datasets by spatial region resulted in a clarification of seasonal patterns with similar factors relating to algal activity being the major correlates of the seasonal pattern. A basic seasonal pattern of lower scores in the spring increasing steadily to a peak in July and August followed by a steady decline through the fall was observed in the cove. In the river, the pattern of increases tended to be delayed slightly in the spring. Results indicate that the study area can be effectively monitored with fewer study sites provided that at least one is located in each of the spatial regions.     

Spatial and seasonal distribution of 17 endocrine disruptor compounds in an urban estuary (Mondego River,Portugal): evaluation of the estrogenic load of the area

The Mondego River estuary demonstrates signs of pollution, but the levels of endocrine disrupting compounds (EDCs), such as the natural (17β-estradiol and estrone) and pharmaceutical (17α-ethynylestradiol) estrogens, xenoestrogenic industrial pollutants (4-octylphenol, 4-nonylphenol, and their mono- and diethoxylates and bisphenol A), phytoestrogens (formononetin, biochanin A, daidzein, and genistein), and sitosterol were either poorly or never measured in this area. Thus, to conclude about the influx of EDCs in this estuary, water samples were taken every 2 months, during 1 year (2010) in low tide, at eight sites distributed along the estuary. Water samples (1 L) were preconcentrated in the Oasis HLB cartridges and cleaned in silica cartridges before their analysis by GC-MS. In summer, potentially hazardous amounts of estrogens (≈26 ng L^?1), alkylphenols (≈11.5 μg L^?1), alkylphenolethoxylates (≈13 μg L^?1), and phytoestrogens (≈5.6 μg L^?1) were measured. These data suggest that changes in the hydrodynamics of the estuary coupled with the increase of water temperatures interfere with the amount of EDCs in the water. Complementary physicochemical parameters also point to high levels of anthropogenic pollution in this area. Globally, the estrogenic load, expressed in ethynylestradiol equivalents, attained 71.8 ng L^?1 demonstrating that, all together, the measured EDCs pose important health risks for both biota and humans.     

Brominated flame retardants in the environment of Asia-Pacific: an overview of spatial and temporal trends

In this paper, we summarize spatial and temporal trends of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) in coastal and marine biota, and further assess human exposure to these brominated flame retardants (BFRs) in Asia-Pacific. The review is based mainly on the studies that were conducted in our laboratory and utilized samples archived in the environmental specimen bank (es-BANK) of Ehime University, Japan. The studies suggest that the target BFRs are ubiquitous in the environment of Asia-Pacific. Examination of spatial trends reveals that concentrations of these contaminants are relatively high in samples from Korea, South China and Japan. In general, the magnitude of environmental contamination by PBDEs in Asia-Pacific, as well as human exposure to these contaminants, seem to be comparable to or slightly higher than in Europe, but lower than in North America. Evaluation of temporal trends in concentrations of BFRs in marine mammals from the coastal waters of Japan and China showed drastic increase during the last 30 years. These changes in BFR levels in samples from Japan were in line with trends in production/use of the commercial formulations. Since the withdrawal of some PBDE products from the Japanese market in the 1990s, concentrations of HBCDs appear to exceed those of PBDEs, reflecting increasing usage of HBCDs over PBDEs. The increasing environmental contamination by BFRs in Chinese coastal waters indicates that contamination by BFRs has already become evident, even in developing countries. In view of the rising environmental levels and the high consumption volume of BFRs in Asia, further efforts should be made to monitor environmental contamination by these chemicals in order to identify sources and reduce emissions.     

River discharge as a major driving force on spatial and temporal variations in zooplankton biomass and community structure in the Godavari estuary India

Variability in horizontal zooplankton biomass distribution was investigated over 13 months in the Godavari estuary, along with physical (river discharge, temperature, salinity), chemical (nutrients, particulate organic matter), biological (phytoplankton biomass), and geological (suspended matter) properties to examine the influencing factors on their spatial and temporal variabilities. The entire estuary was filled with freshwater during peak discharge period and salinity near zero, increased to ~ 34 psu during dry period with relatively high nutrient levels during former than the latter period. Due to low flushing time (< 1 day) and high suspended load (> 500 mg L^?1) during peak discharge period, picoplankton (cyanophyceae) contributed significantly to the phytoplankton biomass (Chl-a) whereas microplankton and nanoplankton (bacillariophyceae, and chlorophyceae) during moderate and mostly microplankton during dry period. Zooplankton biomass was the lowest during peak discharge period and increased during moderate followed by dry period. The zooplankton abundance was controlled by dead organic matter during peak discharge period, while both phytoplankton biomass and dead organic matter during moderate discharge and mostly phytoplankton biomass during dry period. This study suggests that significant modification of physico-chemical properties by river discharge led to changes in phytoplankton composition and dead organic matter concentrations that alters biomass, abundance, and composition of zooplankton in the Godavari estuary.     

Comparing spatial and temporal changes in metal trends (Cr,Ni, Pb and Zn) on the Portuguese shelf since the 1970s

Comparison between an archive dataset, collected during the 1970s (1974–1977), and samples taken during the PALEO1 cruise (2002) enabled evaluation of large-scale and long-term spatiotemporal changes in Al, Cr, Ni, Pb and Zn contents in bulk surface sediments in four areas of the Portuguese shelf. The so-called gradient method (GM) with normalisation to Al, a proxy for terrigenous clay content, was applied. The studied areas are distributed from north to south along the western margin, with the northernmost located off shore the Ave and Douro rivers, a central one located off shore the Lis River and a southern one located off shore the Mira River. One-way ANOVA and Kruskal-Wallis tests were used to identify differences among study areas and periods of sample collection. A comparison of metal contents in 2002 samples with the Portuguese classification scheme regulation for deposition of dredged materials in coastal areas indicates good environmental quality in terms of Cr, Ni, Pb and Zn levels. Nevertheless, the GM results suggest an increase in metal loadings relative to Al from the 1970s to the 2002 samples (except for Pb). The Algarve area on the southern shelf is characterised by having high number of sites with metal level on class 2. These high values have traditionally been explained by a substantial supply of natural metals from the Guadiana, Tinto and Odiel rivers that drain areas Iberian Pyrite Belt formations. This supply has probably been magnified by present and past mining activities. For quality evaluation of marine sediments, especially when using total metal contents, this study shows the importance of considering all possible sources of metal loading. The natural grain size and composition variability have also a crucial influence on the metal content, and the combined evaluation allows a more holistic perspective.