Biogeochemistry of nonylphenol ethoxylates in urban estuarine sediments

We have examined the concentrations and distributions of nonylphenol ethoxylate (NPEO) surfactants and their primary neutral metabolites in two dated sediment cores collected in 1988 and 1996 from a depositional area proximal to a wastewater treatment plant within Jamaica Bay, NY. Total NPEO concentrations ranged from >50 microg/g near the surface (4-6 cm, deposited ca. 1990) to below detection limits (<0.1 microg/g) at 50 cm depth (deposited ca. 1940). The general decrease in NPEO concentrations with increasing depth in sediment reflected increased commercial use of these compounds over the last 50 yr. NPEO ethoxymer distributions in recent sediments were dominated by NP(0-3)EO, consistent with the increased relative input of these particular ethoxymers to the estuary following the upgrade of local biological sewage treatment processes to full activated sludge in the late 1970s. NPEO ethoxymer profiles in deeper sediments were characterized by relatively higher proportions of unmetabolized, highly ethoxylated NPEOs. Depth profiles of NP1EO and NP in the upper portion of the sediment core showed evidence for in situ diagenetic conversion of NP1EO to NP. However, comparison of NPEO concentrations in selected strata from the core collected in 1996 with those in matched strata from a core collected from the same location in 1988 provided no evidence for in situ degradation of total NPEOs during the elapsed 8 yr between collection dates.     

Distribution and behavior of nonylphenol, octylphenol, and nonylphenol monoethoxylate in Tokyo metropolitan area: their association with aquatic particles and sedimentary distributions

Distributions of alkylphenols (APs) [i.e., nonylphenol (NP), octylphenol (OP)], and nonylphenol monoethoxylate (NP1EO) in wastewater effluents, river water, and riverine and bay sediments in the Tokyo metropolitan area were demonstrated. During sewage treatments, NP and OP were efficiently removed from the sewage effluents through activated sludge treatments. Greater removal for NP (93% on average) than OP (84% on average) was consistent with their partitioning behavior to particles in primary and secondary effluents. NP concentrations in the river water samples ranged from 0.051 to 1.08 microg/L with higher concentrations in summer and spring than in colder seasons. In the river water samples, approximately 20% of NP was found in the particulate phase. Organic carbon-normalized apparent partition coefficients (K'OC) for NP (10(5.22 +/- 0.38)) and OP (10(4.65 +/- 0.42)) were 1 order of magnitude higher than those expected from their octanol-water partition coefficients (K(OW)), indicating strong affinity of APs to aquatic particles. Among NP isomers, no significant differences in their K'OC values were suggested. This is consistent with surprisingly uniform isomer peak profiles among the technical standard and all the environmental samples analyzed. NP and OP were widely distributed in the river sediments in Tokyo, and relatively high concentrations (0.5-13.0 microg/g dry) of NP were observed in a long reach (approximately 10 km) in the Sumidagawa River. In situ production of APs in the river sediment was suggested. Seaward decreasing trend in APs concentration was observed from the estuary to the Tokyo Bay. APs were well preserved in a sediment core collected from the bay. The profile shows subsurface maximum of AP concentrations in the layer deposited around the mid-1970s. The recent decrease in AP concentrations can be attributed to the legal regulation of industrial wastewater in the early 1970s.     

Sequestration of nonylphenol in sediment from Bohai Bay, North China

The ubiquity of nonylphenol (NP) in aquatic environments has been well documented, and the long-term fate of NP in sediments is a concern from the viewpoint of risk assessment due to its endocrine-disrupting effects. This paper reports on the assessment of long-term fate of NP in marine sediments by determining extractable and nonextractable fractions of NP in surface sediments and a sediment core from Bohai Bay, North China. The extractable fraction was operationally defined as the fraction of NP that was extracted with a solvent mixture of methanol/methylene chloride, and the nonextractable fraction was the portion of NP that can be released from the sediments by alkaline hydrolyzing after the initial solvent extraction. The total concentrations (extractable and nonextractable) of NP were 3.4-34.3 ng/g dw in the surface sediments and 2.2-17.7 ng/g dw in the sediment core. Depending on the sedimentation time, the percentage of nonextractable NP relative to the total NP in the core ranged from 38 to 99%. Based on the relationship between the percentage of nonextractable NP in sediments and sedimentation time, the sequestration rate of NP in the sediment core from Bohai Bay was estimated to be 0.94% x a(-1). These results have important implications in understanding the geochemical fate of NP in sediments.     

Aerobic biodegradation studies of nonylphenol ethoxylates in river water using liquid chromatography-electrospray tandem mass spectrometry

The aerobic biodegradation of nonylphenol ethoxylates (A9PEO) was kinetically investigated in a laboratory-scale bioreactor filled with riverwater, spiked at a concentration of 10 mg L(-1) nonionic surfactants. Analyses of the samples applying liquid chromatography-electrospray mass spectrometry (LC-ES-MS) after solid-phase enrichment revealed a relatively fast primary degradation of A9PEO with >99% degradation observed after 4 days. Contrary to the generally proposed degradation pathway of EO chain shortening, it could be shown that the initiating step of the degradation is omega-carboxylation of the individual ethoxylate chains: metabolites with long carboxylated EO chains are identified (A9PEC). Further degradation proceeds gradually into short-chain carboxylated EO with the most abundant species being AgPE2C. The oxidation of the nonyl chain proceeds concomitantly with this degradation, leading to metabolites having both a carboxylated ethoxylate and an alkyl chain of varying lengths (CAPEC). The identity of the CAPEC metabolites was confirmed by the fragmentation pattern obtained with LC-ES-MS/MS. Both A9PEC and CAPEC metabolites are still present in the bioreactor after 31 days. In the aerobic degradation pathway, A9PEO2 is formed only to a minor extent and is even further degraded in several days. The endocrine disruptor nonylphenol was not found as a metabolite in this study.     

Identification and quantitation of nonylphenol ethoxylates and nonylphenol in fish tissues from Michigan

Nonylphenol (NP) and its lower ethoxylates, nonylphenol monoethoxylate (NPE1) and nonylphenol diethoxylate (NPE2), can be present in aquatic environments at total concentrations of more than 10 microg/L. They are metabolites of nonylphenol polyethoxylates (NPE) and have been found to be weakly estrogenic. To evaluate bioaccumulation potential and identify potential risks posed by these chemicals, concentrations of NP, NPE1, NPE2, and nonylphenol triethoxylate (NPE3) were determined in the tissues of fish inhabiting various waters in Michigan. This method involves extraction of samples using exhaustive steam distillation with concurrent liquid extraction. Concentrations of NP among all sites and species ranged from <3.3 to 29.1 ng/g, ww and varied little among sites. NPE1 was detectable in some samples but at concentrations less than the method detection limit (16.8 ng/g). Concentrations of NPE2 and NPE3 in all samples were less than their respective MDLs of 18.2 and 20.6 ng/g.     

Occurrence and removal of estrogenic short-chain ethoxy nonylphenolic compounds and their halogenated derivatives during drinking water production

The elimination of nonylphenol (NP), nonylphenol mono- and diethoxylates (NP1EO and NP2EO), nonylphenol carboxylates (NP1EC and NP2EC) and their brominated and chlorinated derivatives during drinking water treatment process in Sant Joan Despf waterworks in Barcelona was investigated utilizing a recently developed, highly sensitive LC-MS-MS method. The concentration of these potentially estrogenic compounds in raw water entering waterworks (taken from the Llobregat River, NE Spain) ranged from 8.3 to 22 microg/L, with NP2EC being the most abundant compound. Prechlorination reduced the concentration of short-chain ethoxy NPECs and NPEOs by about 25-35% and of NP by almost 90%. However, this reduction of concentrations was partially due to their transformation to halogenated derivatives. After prechlorination, halogenated nonylphenolic compounds represented approximately 13% of the total metabolite pool, of which 97% were in the form of brominated acidic metabolites. The efficiency of further treatment steps to eliminate nonylphenolic compounds (calculated for the sum of all short-chain ethoxy metabolites including halogenated derivatives) was as follows: settling and flocculation followed by rapid sand filtration (7%), ozonation (87%), GAC filtration (73%), and final disinfection with chlorine (43%), resulting in overall elimination ranging from 96 to 99% (mean 98% for four sampling dates). A few of the nonylphenolic compounds (NP, NP1EC, and NP2EC) were also identified in drinking water; however, the residues detected were generally below 100 ng/L, with one exception for NP2EC in November 2001 when a concentration of 215 ng/L was detected.     

Alkylphenol and alkylphenol-ethoxylates in carp,water, and sediment from the Cuyahoga River,Ohio

The occurrence of alkylphenol and alkylphenol ethoxylates (APEs) was determined over a 74-mile length of the Cuyahoga River, Ohio. Measurable levels of both the octyl and nonyl forms of these abundantly used nonionic surfactants were observed with the nonylphenol (NP) plus nonylphenol ethoxylates (NPEs) typically accounting for greater than 90% of the total APEs in each sample. For all media (water, fish, and sediment) the total NPE (NP + NPE) concentrations were higher in the more urbanized downstream section of the river. Maximum water and fish values were observed immediately downstream (2.1 miles) from the discharge of the Akron WWTP located 35.31 miles from the river mouth and the sediment maxima occurred at the most downstream site near Cleveland. The ranges in concentration fortotal NPEs and their ethoxylate (EO) makeup were as follows: 32-920 ug/kg wet wt (NP 0 to 2 EO) for carp; 0.13-1.0 ug/L (NP 0 to 3 EO) for water; and 250-1020 ug/kg dry wt (NP 0 to 5 EO) for sediment. When the higher ethoxymers (NP 6 to 17 EO) were added to these sediment totals, the average total estimated NPE concentrations were 1.3-1.8 times higher.     

Retrospective monitoring of alkylphenols and alkylphenol monoethoxylates in aquatic biota from 1985 to 2001: results from the German Environmental Specimen Bank

Breams (Abramis brama) and zebra mussels (Dreissena polymorpha) from freshwater, and common mussels (Mytilus edulis) from marine ecosystems, archived in the German Environmental Specimen Bankwere analyzed for the presence of 4-nonylphenol (NP), 4-tert-octylphenol (OP), nonylphenol monoethoxylate (NP1EO), and octylphenol monoethoxylate (OP1EO). The samples were collected in the German rivers Elbe, Rhine, and Saar, and in Lake Belau between 1992 and 2001, as well as in the North Sea and Baltic Sea between 1985 and 2001. The main purpose of the study was to investigate the effectiveness of imposed reduction measures regarding the use of alkylphenol ethoxylates. NP1EO and OP were detected in all breams. NP was predominantly above the limit of quantification (LOQ, 2 ng/g; all data on a wet weight basis), and OP1EO was mostly below the LOQ (0.2 ng/g). Maximal concentrations of 112 ng/g NP, 259 ng/g NP1EO, 5.5 ng/g OP, and 2.6 ng/g OP1EO were found in Saar breams from 1994. NP was detected in all zebra mussels from the river Elbe (up to 41 ng/g), whereas in rather few samples OP and NP1EO were found at low levels. OP1EO was not detected in any sample. Concentrations in mussels and breams from the reference site Lake Belau were below the LOQ for all compounds. In marine biota NP was found until 1997 with maximum concentrations up to 9.7 ng/g, whereas NP1EO was detected at levels between 1.7 and 12.9 ng/g in very few samples collected at the end of the 1980s. A tendency of the concentrations to decrease was obvious for all sampling sites; it was most pronounced for NP1EO and NP after 1996/1997. The effectiveness of the reduction measures is most evident at the Saar sampling site Güdingen and the North Sea sampling site Eckwarderh?rne.     

Spatial and habitat-based variations in total and methyl mercury concentrations in surficial sediments in the San Francisco Bay-Delta

Recent studies indicate significant amounts of mercury (Hg) are annually transported into the San Francisco Bay-Delta (Bay-Delta) as a result of historic gold and Hg mining activities. We examined temporal and spatial variation in concentrations of total Hg (Hg(T)) and monomethylmercury (MMHg) in surficial sediments of various ecosystem types in the Bay-Delta. We sampled surficial sediments across the Bay-Delta system and found Hg(T) sediment concentrations in the central Delta were generally 100-200 ng g(-1) and increased westward through Suisun Bay to 250-350 ng g(-1). MMHg concentrations in the central Delta were between 1 and 3 ng g(-1), while those in sediments in the perimeter waterways and adjacent bays were less than 1 ng g(-1). Six sites were monitored monthly for over a year to identify seasonal changes in Hg sediment concentrations. Hgtau sediment concentrations ranged from 48 to 382 ng g(-1) and varied as a function of location not season. However, MMHg concentrations varied seasonally, increasing from 1 ng g(-1) during winter months to 6 ng g(-1) during spring and summer. Transects conducted at three marshes in the central Delta revealed MMHg sediment concentrations of 4-8 ng g(-1) at the interior and 2 ng g(-1) at the exterior of the marshes. Habitat type was a major factor controlling MMHg concentration and the MMHg to Hg(T) ratio in sediments of the Bay-Delta. MMHg was significantly correlated to Hgt (r2 = 0.49) in marsh sediments.     

Chlorinated paraffins in sediments from the Pearl River Delta, South China: spatial and temporal distributions and implication for processes

Short-chain and medium-chain chlorinated paraffins (SCCPs and MCCPs) were measured in sediments from ponds, rivers and tributaries, and an estuary, as well as a sediment core in the Pearl River Delta (PRD), South China, to comprehensively investigate the spatial and temporal distributions of CPs. The concentrations of SCCPs and MCCPs in sediment were varied from 320 to 6600 ng/g and from 880 to 38,000 ng/g, respectively. Elevated CP concentrations were found in pond sediments (means of 2800 and 21,000 ng/g for SCCPs and MCCPs) in the e-waste recycling area and in river sediments (means of 1200 and 3900 ng/g for SCCPs and MCCPs) in the highly industrialized areas. The significant positive correlations between SCCP concentration and MCCPs/SCCPs in the highly industrialized areas reflected the emission of local industry activities, while the significant negative correlations in the low industrial activity areas could be linked to long-range transportation of CPs. An increased abundance of short chain and low chlorinated congeners was observed in the low industrial activity areas compared to the industrialized areas. The preferred transportation of short chain and low chlorinated congener CPs and the dechlorination of higher chlorinated congeners CPs were the most likely reasons. The vertical profile of CPs in the sediment core indicated a rapid increase in the usage of CPs and a shift to more MCCPs in recent years. The decreased chlorine content of CPs with increasing sediment depth indicated the possibility of dechlorination of higher chlorinated congeners (Cl(9) and Cl(10)) after deposition in sediments with greater dechlorination potential for short chain CPs than long chain CPs.     

黄河(兰州段)壬基酚聚氧乙烯醚及其降解产物污染的初步研究

本文以黄河(兰州段)为研究对象,对其流域的4个排污点的水样和6个断面各个介质(包括水体、悬浮颗粒物和沉积物)中壬基酚聚氧乙烯醚(NPnEO)及其降解产物壬基酚的污染进行调查。结果表明,4个排污点水样中分别含有浓度不等的NP;6个断面采样点中,大分子的NPnEO(n>2)在各个介质中均未检出,水样中NP在0.24~2.1μg/L之间,NP1EO在0.060~0.35μg/L之间,NP2EO在0.039~0.26μg/L之间。     

Sorption of phenanthrene to environmental black carbon in sediment with and without organic matter and native sorbates

Strong sorption to soot- and charcoal-like material (collectively termed black carbon or BC) in soils and sediments is possibly the reason for recent observations of elevated geosorbent-water distribution ratios, slow desorption, limited uptake, and restricted bioremediation. We evaluated the role of environmental BC in the sorption of phenanthrene (PHE) to a polluted lake sediment from a Rhine River sedimentation area. Sorption isotherms were determined over a wide concentration range (0.0005-6 microg/ L) for the original sediment (with organic matter or OM, native sorbates, and BC), sediment from which we had stripped > 90% of the native sorbates (only OM and BC), and sediment combusted at 375 degrees C (only BC). The sorption isotherms of the original and stripped sediments were almost linear (Freundlich coefficient or n(F) > 0.9), whereas the isotherm of the BC remaining after the sediment combustion was highly nonlinear (n(F) = 0.54). At low concentrations (ng/L range), PHE sorption to BC in the combusted sediment was found to exceed the total PHE sorption in the original and stripped sediments. This implies that it may not be possible to use a BC-water sorption coefficient measured in combusted sediment to estimate total sorption to the original sediment. This "intrinsic" BC-water sorption coefficient after combustion was calculated to be 9 times larger than the "environmental" one in the untreated sediment. Competition between the added PHE and the native PAHs and/or OM may explain this difference. It appears that, at low aqueous PHE concentrations (ng/L and below), BC is the most important geosorbent constituent with respect to sorption. At higher concentrations (microg/L), BC sorption sites become saturated and BC sorption is overwhelmed by sorption to the other OM constituents. Because sorption is a central process affecting contaminant behavior and ecotoxicity, understanding this process can strongly contribute to risk assessment and fate modeling.     

Polybrominated diphenyl ethers in the sediments of the Great Lakes. 3. Lakes Ontario and Erie

Sediment cores were taken in 2002 in Lakes Ontario and Erie at four locations. A total of 48 sediment samples were characterized, dated using 210Pb, and analyzed for 10 congeners of polybrominated diphenyl ethers (PBDEs) including BDE209 as well as 39 congeners of polychlorinated biphenyls (PCBs). The surficial concentrations of nine tri- through hepta-BDE congeners (sigma9PBDE) are 4.85 and 6.33 ng g(-1), at sampling sites ON40 and ON30 in Lake Ontario, and 1.83 and 1.95 ng g(-1) at ER37 and ER09 in Lake Erie, respectively, based on dry sediment weight. The surficial BDE209 concentrations are 242 and 211 ng g(-1) at ON40 and ON30 and 50 and 55 ng g(-1) at ER37 and ER09. The sigma(9-) PBDEs fluxes to the sediment around 2002 are 147 and 195 pg cm(-2) year(-1) at ON40 and ON30 and 136 and 314 pg cm(-2) year(-1) at ER37 and ER09, respectively. The fluxes of BDE209 are 6.5 and 7.3 ng cm(-2) year(-1) at ON30 and ON40 and 3.7 and 8.9 ng cm(-2) year(-1) at ER37 and ER09, respectively. Dramatic increases in PBDE concentrations and fluxes upward toward the sediment surface and the present time are evident at both locations in Lake Ontario, while PCBs concentrations peak in the middle of sediment cores around the dated time of 1970s and 1960s. For both locations of Lake Erie, the increasing trends of both PBDEs and PCBs from the bottom to the surficial segments were distorted by sediment mixing. BDE209 is the most abundant congener among PBDEs in the sediments, constituting about 96 and 91% of the total PBDEs on mass basis in Lakes Ontario and Erie, respectively.     

Polybrominated diphenyl ethers in the sediments of the Great Lakes. 2. Lakes Michigan and Huron

Sediment cores were taken in 2002 in Lakes Michigan and Huron at six locations. A total of 75 samples were characterized, dated using 210Pb, and analyzed for 10 congeners of polybromodiphenyl ether (PBDE) including BDE209, as well as 39 congeners of polychlorinated biphenyls (PCBs). The concentrations of nine tri- through hepta-BDE congeners (Sigma9PBDE) in the surficial sediments range from 1.7 to 4 ng g(-1) for Lake Michigan and from 1.0 to 1.9 ng g(-1) for Lake Huron, on the basis of the dry sediment weight. The Sigma9PBDEs fluxes to the sediment around the year 2002 are from 36 to 109 pg cm(-2) yr(-1) in Lake Michigan and from 30 to 73 pg cm(-2) yr(-1) in Lake Huron, with spatial variations in both lakes. The flux of BDE209 ranges from 0.64 to 2.04 ng cm(-2) yr(-1) and from 0.67 to 1.41 ng cm(-2) yr(-1) in Lake Michigan and Lake Huron, respectively. Dramatic increases in PBDE concentrations and fluxes upward toward the sediment surface and the present time are evident at all locations. The inventory of PBDEs in both lakes appears to be dependent upon latitude and the proximity to populated areas, implying that north-bound air plumes from urban areas are the major sources of PBDEs found in the lake sediments at locations away from the shores. Heavier congeners are more abundant in the sediments than in air and fish samples in the region. BDE209 is about 96% and 91% of the total PBDEs on a mass basis in Lake Michigan and Lake Huron, respectively; both are higher than the 89% found in Lake Superior, although a t test shows that the value for Lake Huron is not statistically different from that for Lake Superior at the 95% confidence level.     

Distribution and mass inventories of polycyclic aromatic hydrocarbons and organochlorine pesticides in sediments of the Pearl River Estuary and the northern South China Sea

Surface sediment (0-5 cm) samples were collected from the Pearl River Estuary (PRE) and the adjacent northern South China Sea (SCS) in July 2002 and analyzed for 25 polycyclic aromatic hydrocarbons (PAHs) and 8 organochlorine pesticides (OCPs) including dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), and heptachlor. The total PAHs and OCPs concentrations were 138-1100 and 0.18-3.57 ng/g dry weight, respectively. Compositional pattern analysis suggested that PAHs in the PRE were derived from both pyrogenic and petrogenic sources, whereas most PAHs in the northern SCS were pyrogenically originated. The concentrations of both PAHs and OCPs were higher in the PRE than in the northern SCS, and a decreasing trend with the distance from the estuary to the open sea was observed. In addition, perylene was a predominant component in all samples and clustered with PAH compounds with high log Kow values (from phenanthrene). These findings indicated that river outflows were the major source of contamination in the offshore sediments. A preliminary assessment suggested that atmospheric deposition contributed only a minor portion of PAHs or OCPs in the sediments of the northern SCS. The sediment (0-5 cm) mass inventories were 126 and 423 metric tons for PAHs and were 0.4 and 1.4 metric tons for OCPs in the PRE and the northern SCS, respectively. Clearly, contaminated sediments of the northern SCS may be a potential source of PAHs and OCPs to the global oceans.     

Mercury mobilization in estuarine sediment porewaters: a diffusive gel time-series study

To assess the lability of porewater and sediment solid-phase mercury (Hg), mercapto-substituted siloxane gels were deployed within the sediments of the Penobscot estuary in Maine. Gel deployments occurred in time series and at discrete sediment depths. A sediment distribution coefficient (K(D)) was estimated by modeling the resultant gel Hg uptake. For deployments > 1 day, depth-averaged gel Hg uptake was significantly greater at depth (Zone B 6-20 cm) than in the vicinity of the sediment-water interface (Zone A 0-5 cm), with uptake ultimately reaching 16.7 +/- 4.9 ng Hg g(-1) gel versus 35.5 +/- 3.8 ng Hg g(-1) gel for Zone A versus Zone B, respectively. For Zone A, a simple diffusive model adequately describes gel mass flux, suggesting that Hg repartitioning from the solid phase does not generate a net Hg source term within the time frame of gel deployment. For Zone B, model-determined values of K(D) (K(D) = 25-75) were considerably smaller than literature values typically based on total sediment Hg concentration. The magnitude of the modeled K(D) suggests that it is a small fraction of total sediment-sequestered Hg that is likely sensitive, via interaction with porewater ligands, to the presence of an external sink. These observations of low general Hg reactivity suggest that the net porewater Hg pool may be properly defined as a function of porewater ligand production. Such a definition highlights the importance of microbially mediated diagenesis in controlling Hg cycling within estuarine sediments.     

Occurrence of methyl tert-butyl ether (MTBE) in riverbank fiftered water and drnking water produced by riverbank filtration. 2

Bank filtration of river or lake water represents an efficient and natural purification process used for the drinking water production in many countries and at an amount of about 15-16% in Germany. From experiences over decades particularly at the river Rhine and Elbe, it is known that the occurrence of persistent pollutants in river water can represent a problem for the quality of drinking water produced by bank filtration. The common detection of the gasoline additive methyl tert-butyl ether (MTBE) in drinking water and the announced phase-out of the oxygenate in the U.S. show that MTBE can contaminate large water amounts due to its physicochemical properties. The MTBE situation in the U.S differs from Europe, and significantly lower concentrations in the German environment can be expected. Average MTBE concentrations of 200-250 ng/L in the Lower Main and Lower Rhine river in 2000/2001 were reported. At two sites at the Lower Rhine and Lower Main rivers MTBE concentrations in bank filtered water (n = 22), recovering well water, raw water, and drinking water produced by the water utility at the Lower Rhine site (n = 30) and tap water at Frankfurt/M City (n = 13) were analyzed from 1999 to 2001. Sample analysis is performed by a combination of headspace-solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC/MS) with a detection limit of 10 ng/L and a relative standard deviation of 11%. At the Lower Rhine site up to 80 m from the river an average MTBE concentration of 88 ng/L in riverbank filtered water, recovering well water, and raw water (n = 7) and of 43-110 ng/L in drinking water (n = 3) result. At the Lower Main site up to 400 m from the river MTBE concentrations from 52 to 250 ng/L (n = 7) were measured. Tap water samples at Frankfurt/M (mean of 35 ng/L, maximum of 71 ng/L) were in the same range as MTBE amounts in drinking water at the Lower Rhine site. Measured MTBE amounts eliminated by bank filtration at the Lower Rhine site are comparable to other contaminants. The results of this study show that concentrations measured in river water and drinking water are approximately 2-3 orders of magnitude lower than the U.S. drinking water standard of 20-40 microg/L, represent trace-level concentrations, and are not of major concern nowadays. However, the unfavorable combination of the occurrence of nonpoint MTBE emissions and the persistent behavior of the ether in water even at low concentrations should not be neglected in future discussion. The reported MTBE concentrations are relevant for precautionary aspects. MTBE concentrations in German river water show a tendency toward increasing concentrations since 1999, and in the future possible higher concentrations could represent a risk for the quality of drinking water that is being produced by water utility using bank filtered river water.     

Concentration and bioaccumulation of dechlorane compounds in coastal environment of northern China

Dechloranes, including Dechlorane Plus (DP), Mirex (Dechlorane), Dechlorane 602 (Dec 602), Dechlorane 603 (Dec 603), and Dechlorane 604 (Dec 604), were determined using GC-MSD for water, sediment and oyster samples collected at 15 sampling sites near the Bohai and Huanghai Sea shore area of northern China in 2008. DP and Mirex were detected in most water, sediment, and oyster samples, which indicated widespread distribution of these two compounds. The mean concentrations in water, sediment and oyster samples, respectively, were 1.8 ng/L, 2.9 ng/g dry weight (dw) and 4.1 ng/g wet weight (ww) for total DP, and 0.29 ng/L, 0.90 ng/g dw, and 2.0 ng/g ww for Mirex. Dec 602 and Dec 603 were not detected in water but in small portions of the sediment and oyster samples, showing a low level of contamination by these two chemicals in the region. Strong and significant correlations were found between total DP and Mirex concentrations in water, sediment and oyster samples, probably suggesting similar local sources of these two chemicals. Dec 604 was not found in any samples. The biota-sediment accumulation factor (BSAF) of DP, Mirex, and Dec 602 declined along with the increase of their logarithm of octanol-water partition coefficients (log Kow), possibly indicating that compounds with lower log Kow (like Mirex and Dec 602) accumulated more readily in biota. The mean fractional abundance of syn-DP (fsyn) was 0.34 in water samples, a value lower than that in Chinese commercial mixture (0.41), while the mean fsyn for surface sediment (0.44) and oyster (0.45) samples were higher than technical values. Enrichment of syn-DP in oyster was in agreement with previously reported findings in Great Lakes fish. Enrichment of syn-DP in marine surface sediments, however, is contrary to data reported for fresh water sediments. To our knowledge this is the first report of Dec 602, Dec 603, and Dec 604 in a marine environment and also the first report of Dechloranes in marine biota.     

Mercury speciation and microbial transformations in mine wastes, stream sediments, and surface waters at the Almadén Mining District, Spain

Speciation of Hg and conversion to methyl-Hg were evaluated in mine wastes, sediments, and water collected from the Almadén District, Spain, the world's largest Hg producing region. Our data for methyl-Hg, a neurotoxin hazardous to humans, are the first reported for sediment and water from the Almadén area. Concentrations of Hg and methyl-Hg in mine waste, sediment, and water from Almadén are among the highestfound at Hg mines worldwide. Mine wastes from Almadén contain highly elevated Hg concentrations, ranging from 160 to 34,000 microg/g, and methyl-Hg varies from <0.20 to 3100 ng/g. Isotopic tracer methods indicate that mine wastes at one site (Almadenejos) exhibit unusually high rates of Hg-methylation, which correspond with mine wastes containing the highest methyl-Hg concentrations. Streamwater collected near the Almadén mine is also contaminated, containing Hg as high as 13,000 ng/L and methyl-Hg as high as 30 ng/L; corresponding stream sediments contain Hg concentrations as high as 2300 microg/g and methyl-Hg concentrations as high as 82 ng/g. Several streamwaters contain Hg concentrations in excess of the 1000 ng/L World Health Organization (WHO) drinking water standard. Methyl-Hg formation and degradation was rapid in mines wastes and stream sediments demonstrating the dynamic nature of Hg cycling. These data indicate substantial downstream transport of Hg from the Almadén mine and significant conversion to methyl-Hg in the surface environment.