Nachweis von Industriechemikalien (HPS,BPS und SPS) im Oberflächenwasser

Occurrence of Industrial Chemicals (HPS, BPS, and SPS) in Surface Water The paper gives the results of water examinations for different phenylsulfonamides. Random samples taken every month between May 1999 and August 2000 from surface water out of the river Rhine (kilometer 838), the river Ruhr (Mülheim Styrum) and the river Emscher (Oberhausen center) were tested for the corrosion inhibiting agent 6‐[methyl(phenylsulfonyl)amino]‐hexanoic acid (HPS) as well as its metabolites 4‐[methyl‐(phenylsulfonyl)amino]‐butanoic acid (BPS) and sarkosin‐N‐(phenylsulfonyl) (SPS). Furthermore, the sewage plant effluents of two municipal wastewater treatment plants from the rural area were also included in the monitoring program. The analytical method includes solid‐phase extraction (SPE), a derivatization step as well as gas chromatography mass spectrometry (GC‐MS). SPS is regularly found in all investigated surface waters, but only occasionally in the effluents of the two rural sewage plants. The median values for SPS amount to 0.09 μg/L in the river Rhine, 0.60 μg/L in the river Ruhr, and 0.70 μg/L in the river Emscher. BPS can only be found in the river Ruhr (median value: 0.08 μg/L) and in the river Emscher (median value: 0.41 μg/L). HPS was regularly found in a surface water for the first time. This substance can be detected in the Emscher through the whole measurement period. The median value for HPS amounts to 1.78 μg/L. Aditionally, the validation characteristics of an alternative analytical method including solid‐phase microextraction (SPME) is worked out. The fully automated process includes an on‐fiber methylation step and the GC‐MS. The repeatability standard deviation of the process amounts to RSD < 12%. Detection limits between 0.07 and 0.70 μg/L are achieved.     

Detection of Pharmaceuticals and Personal Care Products in Agricultural Soils Receiving Biosolids Application

Increasing research has suggested that biosolids generated from municipal wastewater treatment can be a major sink for many pharmaceuticals and personal care products (PPCPs) and their land application potentially introduces these contaminants into the terrestrial and aquatic environments. In this study, methods were developed for the analysis of 14 PPCPs in biosolids and soils using pressurized liquid extraction, solid phase extraction and liquid chromatography‐tandem mass spectrometry. Recoveries were over 50% for all analytes except diphenhydramine (?30%) in soils. Soil properties or type of biosolids showed minor effects on method recoveries. Estimated method limits of quantification (LOQ) range from 0.1–15 ng g^–1 for soil and 0.3–27 ng g^–1 for biosolids. A field study utilizing the methods revealed that other than carbamazepine‐10,11‐epoxide, all targeted compounds were detected in biosolids. Diphenhydramine, fluoxetine, triclosan and triclocarban were detected up to the μg g^–1 range with the highest concentration of 23 μg g^–1 for triclocarban. Seven of the PCCPs found in biosolids were also detected in agricultural soils amended with these biosolids and several (carbamazepine, diphenhydramine, and triclocarban) appeared to be persistent in soils. Triclocarban was also found most abundant in soils with the highest average concentration of 0.2 μg g^–1 while the rest of compounds were in the lower ng g^–1 range. Generally, the concentrations found on the fields were 2–3 degrees of magnitude lower than in the biosolids, which is likely to be due to dilution, degradation and leaching processes.     

Quantification of Diclofenac in Hospital Effluent and Identification of Metabolites and Degradation Products

In this study the occurrence of diclofenac and sub‐products in effluent emerging from the University Hospital at the Federal University of Santa Maria was investigated. One metabolite was identified and, in aqueous solution, three degradation products. The quantification was conducted by means of HPLC‐DAD, and the determination of metabolite and degradation products by LC–ESI–MS/MS–QTrap. For the HPLC‐DAD method, a 70:30 mixture of methanol/sodium phosphate was used in isocratic mode. For the LC–ESI–MS/MS–QTrap determinations, a mobile phase, where phase A was an ammonium acetate solution 5 × 10^?3 mol L^?1, and phase B was methanol (5 × 10^?3 mol L^?1)/ammonium acetate (9:1, v/v), on gradient mode. The LDs for the HPLC and LC–MS/MS methods, respectively, were 2.5 and 0.02 µg L^?1, the LQs, 8.3 and 0.05 µg L^?1, and the linear range from 10 up to 2000 µg L^?1 and 0.05 up to 10 µg L^?1. As expected, the LC–ESI–MS/MS–QTrap method was more sensitive and less laborious. The metabolite 4′‐hydroxy‐diclofenac was identified. Photolysis was used for the degradation studies and three products of diclofenac were identified (m/z of 214, 286 and 303) in aqueous solution. These results notwithstanding, no degradation products of diclofenac were found in the hospital effluent.     

Perfluorinated compounds in the surface waters of Puget Sound,Washington and Clayoquot and Barkley Sounds,British Columbia

Perfluorinated compounds (PFCs) are persistent organic contaminants detected in various environmental matrices including sediment, air, biota, and water. The objectives of this study was to evaluate the occurrence of these contaminants within the surface waters of the Pacific Northwest region and through relative concentrations and ratios, to assess their possible sources. Surface waters were extracted and analyzed by liquid chromatography tandem mass spectrometry (LCMSMS). Perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were the most commonly detected PFCs. Total PFC concentrations detected ranged from 1.5 to 41 ng L-1. Surprisingly, levels of PFCs in the more urbanized Puget Sound waters were comparable to those measured from the more rural region of Clayoquot and Barkley Sounds in British Columbia. The ratio of PFHpA/PFOA were also similar between the two regions, suggesting that the burden of PFCs throughout the region results from direct input from regional sources.     

Emerging organic contaminants in coastal waters: Anthropogenic impact,environmental release and ecological risk

This study provides a first estimate of the sources, distribution, and risk presented by emerging organic contaminants (EOCs) in coastal waters off southwestern Taiwan. Ten illicit drugs, seven nonsteroidal anti-inflammatory drugs (NSAIDs), five antibiotics, two blood lipid regulators, two antiepileptic drugs, two UV filters, caffeine, atenolol, and omeprazole were analyzed by solid-phase extraction and liquid chromatography coupled to tandem mass spectrometry (SPE–LC–MS/MS). Thirteen EOCs were detected in coastal waters, including four NSAIDs (acetaminophen, ibuprofen, ketoprofen, and codeine), three antibiotics (ampicillin, erythromycin, and cefalexin), three illicit drugs (ketamine, pseudoephedrine, and MDMA), caffeine, carbamazepine, and gemfibrozil. The median concentrations for the 13 EOCs ranged from 1.47 ng/L to 156 ng/L. Spatial variation in concentration of the 13 EOCs suggests discharge into coastal waters via ocean outfall pipes and rivers. Codeine and ampicillin have significant pollution risk quotients (RQ > 1), indicating potentially high risk to aquatic organisms in coastal waters.     

Determination of Selected Endocrine Disrupter Compounds at Trace Levels in Sewage Sludge Samples

Simultaneous determination of endocrine disrupter compounds (EDCs), namely diltiazem, progesterone, benzylbutylphthalate (BBP), estrone, and carbamazepine (Cbz) were performed by using high performance LC–electrospray tandem MS. The ultrasound‐aided sequential extraction of sludge samples was optimized to increase extraction efficiencies of the analytes; ranging between 93.0–98.3% recovery. The limit of detection values for diltiazem, progesterone, BBP, estrone, and Cbz were found as 0.78, 0.72, 0.24, 0.75, and 0.72 µg/kg, respectively. Sludge samples taken from Ankara Tatlar; Hurma, Lara and Kemer of Antalya, and Middle East Technical University‐vacuum rotating membrane wastewater treatment plant (WWTP) aeration tanks were analyzed for their EDCs contents under optimized conditions. Diltiazem was found in all the samples in the range between 116.4–180.8 ng/g while progesterone and estrone were not detected in any of the samples analyzed with the exception of Tatlar WWTP. The BBP concentration was between beyond detection and 9195.5 ng/g. In addition, Cbz was found in all the samples ranging from 25.6 to 118.8 ng/g.     

Untersuchungen zum Stickstoff-, Phosphor- und Kaliumeintrag in das Grundwasser nach Gülledüngung

About 53 million tons of liquid manure from the animal husbandry plants of the GDR are used for purposes of organic fertilization per year. Fertilization by liquid manure must be reasonably done, since there should be avoided fertilization and yield losses of agriculture and damages to the ground-water as a drinking-water resource. In dependence on the cultivation of crops, the kinds of graining of soils, the month of application and of the quantity used–referred to the application of nitrogen of liquid manure in kg/ha–the enrichment effect of nitrogen, potassium and phosphorus in infiltration water is determined with the aid of lysimeter investigations. Components of nitrogen which are not used by plants get into ground-water as undesired nitrate, partly through nitrification processes. Unused potassium, too, migrates into ground-water, whereas phosphorus is bound by soil. By proposals for new limit values of load with liquid manure, summarized in tabular form, the valid specifications of the GDR standards “TGL” are criticized.     

Occurrence of the Antimicrobials Sulfamethoxazole and Trimethoprim in Hospital Effluent and Study of Their Degradation Products after Electrocoagulation

In this study, an investigation was carried out into the occurrence of sulfamethoxazole (SMX) and trimethoprim (TMP) in the effluent of the university hospital (HUSM) of the UFSM. The degradation of these antimicrobials by the electrocoagulation (EC) process was also examined, in both the aqueous solution and hospital effluent, and a study was conducted in order to identify the subproducts formed. The experiments were optimized through factorial planning and, also, checked by response surface methodology. The best conditions for EC (achieving 58.0% of chemical oxygen demand (COD) reduction) were obtained by using 13 mA cm^?2, 500 mg L^?1 of NaCl, and 30 mm of interelectrode distance. The quantification of SMX (27.8 µg L^?1) and TMP (6.65 µg L^?1) in the hospital effluent, and the identification of the degradation products were carried out through liquid chromatography‐mass spectrometry quadrupole linear and ion trapping with electrospray ionization (LC‐ESI‐MS/MS_QTrap). Removals of 88.0% (degradation only) and 33.0% (adsorption only) were achieved for aqueous solutions of SMX and TMP, respectively, under optimized conditions. In hospital effluent samples, fortified with additions of SMX and TMP, corresponding removals of 16.0% (degradation) and 28.0% (adsorption) were achieved. This suggests that the EC process is efficient in degrading SMX in aqueous solution, although the same was not the case with TMP. The degradation products of SMX were identified (m/z 256.0 and 288.5); however, only the latter is mentioned in the literature. Toxicological aspects were not considered in this study.     

鄱阳湖流域南昌市城市湖泊水体抗生素污染特征及生态风险分析

采用固相萃取-超高效液相色谱-质谱法对南昌市5个城市湖泊——艾溪湖、瑶湖、青山湖、象湖和东西湖水体的抗生素进行监测,并分析其污染来源和生态风险.结果表明,南昌市5个城市湖泊水体中四环素类、磺胺类、喹诺酮类、林可霉素及大环内酯类5类抗生素的检出浓度范围分别为ND~6.3、ND~32.0、ND~97.2、ND~54.7和ND~98.4 ng/L;红霉素和林可霉素是5个城市湖泊水体中的主要抗生素类型;相比于其他湖泊,南昌市城市湖泊水体中主要检出抗生素浓度总体处于中等水平,其中恩诺沙星的检出浓度高于其他对比湖泊.南昌市城市湖泊中6种主要抗生素的风险商均小于0.1,表明均为最低生态风险;5个城市湖泊的主要生态风险因子分别是艾溪湖为红霉素,瑶湖为磺胺二甲嘧啶,青山湖为罗红霉素,象湖为红霉素,东西湖为磺胺嘧啶.本研究可为南昌市城市湖泊水环境管理,特别是新型污染物的环境管理提供基础依据.     

Extraction of highly polar organophosphorus pesticides from water

Some of the pesticides listed in the European 76/464/EC Directive and in the Directive 2000/60/EC are very polar and require special analytical methodology with respect to their extraction from water. The extraction of the organophosphorus pesticides methamidophos, omethoate, oxydemeton‐methyl, mevinphos and trichlorfon with lg P_OW below 1 was investigated using 21 different solid‐phase materials. Each material was tested on spiked natural water at 4 different pH values, adjusted prior to extraction. The following range of materials were tested: octadecyl silica, polymers, modified silica, ion exchange and carbon. Extraction of the above compounds from water is possible. A relationship between the octanol‐water partition coefficient and recovery rates was obtained not only for octadecyl solid phases but also for some polymeric materials. General conclusions about the use of solid‐phase materials and specific conclusions about the extraction of particular compounds were made. An optimized extraction procedure was deduced and confirmed.     

Presence of Antibiotics in Shallow Groundwater in the Northern and Southwestern Regions of China

Antibiotics are widely used, and there is a serious concern about its adverse impacts on the environment and human health. To our knowledge, prior to this work, there was no evidence of the potential presence of antibiotics in groundwater in China, despite populous speculations. This study reported the detection of 35 target antibiotics of 6 groups (chloramphenicois, lincosamides, marcrolides, quinolones, sulfonamides, and tetracyclines), in shallow groundwater samples collected in northern and southwestern China. Thirty‐four of thirty‐five target antibiotics were detected in the groundwater samples; 73 of 74 monitoring wells contained at least one antibiotic; and at least two antibiotics were detected in 72 of the 74 wells. Ofloxacin (1199.7 ng/L), lincomycin (860.7 ng/L), and norfloxacin (441.9 ng/L) as well as antibiotics with the highest detection frequency such as sulfapyridine (70%), norfloxacin (69%), and lincomycin (64%) were detected at elevated concentrations. The highest detection frequency and concentration of lincosamides were observed in those groundwater samples, but no clear distribution patterns were observed for the six antibiotic groups. Moreover, shallow groundwater in southwestern China seemed to contain most antibiotics, likely due to the high antibiotics discharge and frequent exchange of groundwater with surface matrices. The findings from this work suggest that groundwater in China has been widely contaminated by antibiotics, and presumably other pharmaceutical compounds that have not been investigated to date.     

Problems and Solutions in Pesticide Analysis Using Solid‐phase Extraction (SPE) and Gas Chromatography Ion‐trap Mass Spectrometry Detection (GC‐MS)

In the present study an analytical method was tested for the determination of selected pesticides and metabolites using solid‐phase extraction (SPE) and gas chromatography ion‐trap mass spectrometry (GC‐MS). The extraction efficiency of C18, Isolut ENV+, and Lichrolut EN for SPE was compared for trifluralin, fenitrothion, endosulfan, propargite, 2,4‐D, 3‐methyl‐4‐nitrophenol, 2‐(4‐tert‐butylphenoxy)cyclohexanol, endosulfan sulfate, and 2,4‐dichlorophenol. Isolut ENV+ and C18 showed good results as sorbents and acetone as an elution solvent for SPE for the selected pesticides. Recoveries varied between 36% and 176% with a relative standard deviation of 2...18%. Because of coextracts from the SPE materials, recovery values higher than 100% were obtained for fenitrothion, endosulfan sulfate, and 2,4‐D with C18 as well as for endosulfan sulfate and 3‐methyl‐4‐nitrophenol with Isolut ENV+. A standard addition method was used to verify the occurrence of coextracts in the sample after SPE.     

Bioassay‐directed fractionation for analyzing estrogens in surface waters of the German Baltic Sea

A reversed‐phase fractionation method with subsequent biological and chemical analysis has been developed to estimate the contributions of the most potent estrogens to observed estrogenic effect potentials. Surface water samples were taken in the German Baltic Sea (Inner Wismar Bay and Darss Peninsula, sampling campaign July 2003) and were separated into seven individual fractions. Three fractions showed significant estrogenic activities and clear dose‐dependant responses were obtained in the yeast estrogen screen (YES). In the 2nd fractions liquid chromatographic‐electrospray‐tandem mass spectrometric (LC‐ESI‐MS‐MS) analyses showed the presence of bisphenol A (Inner Wismar Bay: 4.8 ng L^–1 and 6 ng L^–1; Darss Peninsula: 0.91 ng L^–1 and 1.7 ng L^–1) and ethinylestradiol (Inner Wismar Bay: 2.0 ng L^–1 and 6.0 ng L^–1; Darss Peninsula: < MDL and 1.7 ng L^–1), whereas estrogenic activities in the YES were only around 10% of the positive control E2. Although not identified prior in the total extract the natural hormones estradiol (Inner Wismar Bay: 0.13 ng L^–1 and 0.19 ng L^–1; Darss Peninsula: 0.12 ng L^–1 and 0.16 ng L^–1) and estriol (Inner Wismar Bay: < MDL and 0.33 ng L^–1; Darss Peninsula: < MDL) could be detected in the 3rd fractions, where high estrogenic potentials could be observed. The 4th fractions showed high responses as well and estrone were herein quantified with concentrations of 0.16 ng L^–1 and 0.18 ng L^–1 (Darss Peninsula) up to 0.37 ng L^–1 (Inner Wismar Bay). Measured and calculated estradiol equivalents for individual fractions correlated very well (R² = 0.78), when disregarding results of the 2nd fraction, where high deviations occurred.     

Oceanographic distributions of cadmium,zinc, nickel,and copper in the North Pacific

Vertical profiles of Cd, Zn, Ni, and Cu have been determined at three stations in the North Pacific and in the surface waters on a transect from Hawaii to Monterey, California. The distributions found are oceanographically consistent and provide a needed confirmation and extension of several recent studies on the marine geochemistries of these metals. Cadmium concentrations average 1.4 pmol/kg in surface waters of the central North Pacific and show a strong correlation with the labile nutrients, phosphate and nitrate, increasing to values of 1.1 nmol/kg at depths corresponding to the phosphate maximum. Zinc is depleted in surface waters of the central gyre to an average value of 0.07 nmol/kg and increases to a deep maximum of 9 nmol/kg exhibiting a strong correlation with the nutrient silicate. Nickel concentrations average 2.1 nmol/kg in surface central gyre waters and increase to a deep maximum of 11 nmol/kg. Nickel is best correlated with a combination of phosphate and silicate. Copper averages less than 0.5 nmol/kg in surface waters of the central North Pacific and increases gradually to values of 5 nmol/kg in bottom waters. The Cu profiles show evidence of intermediate and deep water scavenging. The involvement of these metals in the internal biogeochemical cycles of the sea is responsible for their distributions which are predictable on the basis of oceanographic parameters.     

Distribution Study of U,V, Mo,and Zr in Different Sites of Lakes Van and Hazar,River and Seawater Samples by ICP‐MS

The aim of this study is to investigate the concentrations of U, Th, V, Mo, and Zr in natural waters taken from Turkey. Among these water species, Lake Van is the largest soda lake and the fourth largest closed basin on Earth. The water samples were collected from 51 locations between 2008 and 2009. The inductively coupled plasma‐MS was used for determinations. The obtained U and Zr concentrations are in the range of 37–110 µg L^?1 and 17–78 µg L^?1 in Lake Van and 0.53–0.81 µg L^?1 and 0.15–0.19 µg L^?1 in Lake Hazar, respectively. The concentration of uranium in other studied waters varies from the lowest 0.09 µg L^?1 in Tigris (Dicle) river to the highest 4.0 µg L^?1 in Mediterranean Sea water. Mean Mo and V concentrations in the studied water samples were found to be in ranges of 0.1–17 and 2.7–113 µg L^?1, respectively. The obtained highest U concentration in Lake Van correlates with the highest Mo and Zr levels compared to the Lake Hazar and river waters. These results imply that there is a young occurrence of uranium minerals around Lake Van. It is concluded that there is about 50.000 ton of uranium in Lake Van water.     

广州市海珠区地表水中致嗅物质及毒性分析

为研究广州市海珠区地表水中的致嗅物质及其毒性,在海珠区珠江前后航道与湖泊池塘采集了21个水样,采用液液萃取气质联用法对其中的土臭素、二甲基异茨醇等5种致嗅物质进行含量检测,并根据水样相关富营养化指标,探究这些致嗅物质的分布和来源.研究结果表明:海珠区地表水中含量最高的两种致嗅物质依次是土臭素(4.0~69.0 ng/L)和二甲基异茨醇(4.1~24.9 ng/L);异臭味问题最严重的地表水体是珠江水,其次为湖泊池塘,水厂取水口的异臭味问题不明显;珠江前航道中致嗅物质的含量高于后航道,其中含量最高的河段为鳌洲码头段至广州大桥段,含量高达40.2~69.0 ng/L;致嗅物质的含量和分布与水体的污染和富营养化程度密切相关,广州市海珠区地表水的净化和治理形势严峻.另外,在可检出的浓度范围内,土臭素和二甲基异茨醇对发光细菌抑制率较高.     

Environmental regulations of agriculture in the Baltic Sea catchment areas, with reference to the European Union and the North Sea

The environmental policies aimed at reducing nutrient emissions from the agricultural sectors in the Baltic states, Poland, Germany and Scandinavia are detailed. The emissions include leaching, run-off and erosion losses of nitrogen and phosphorus, volatile losses of ammonia, and farm waste discharges. Farm waste discharges and nitrate leaching from agricultural fields have received considerable attention during the last few decades, but more recently the remaining loss categories have also been recognized as substantial contributors of nutrients to the environment.

Environmental targets have been set in the Helsinki Commission (HELCOM) Ministerial Declaration of 15 February 1988, stating that a significant reduction (e.g. 50%) of the nutrient load to the Baltic Sea shall be reached before 1995. A similar target for the Oslo and Paris (OSPARCOM) Convention waters has been set by the North Sea ministers, while the EU Nitrate Directive expresses an environmental standard by setting an upper limit to nitrate concentrations in groundwater.

It is argued here that in most instances only marginal reductions in agricultural emissions will be achieved under the current policies before 1995 (or later). Exceptions are seen in transition economy countries where fertilizer consumption and livestock production have decreased significantly. As agriculture is a major source of nutrients to convention waters, the overall 50% reduction target will not be met. Furthermore, it is argued that there is scope for a considerable reduction of losses from agriculture and that the instruments to achieve the objectives are readily available. Measures should focus on the total input of nutrients to the agro-ecosystems and not so much attempt to regulate specific management practices. The more prominent instruments include the reduction or alteration of agricultural subsidies, market considerations and the use of environmental taxes (on fertilizers and nutrients in animal manure) combined with in-depth structural regulations. It is, however, necessary to generate further political willingness to ensure decisions and successful implementation of the various measures—a process which requires public attention.     

Chemical Characterization of Carbonated Natural Mineral Waters Produced in Turkey: Compliance with European Water Quality Standards

In this study, a total of 100 samples from 25 brands of carbonated natural mineral waters (CNMWs) produced in Turkey were analyzed for a total of 36 water quality constituents to determine their suitability for human consumption. Parameters examined include pH, electrical conductivity, ammonia, nitrate, nitrite, sulfate, sulfite, orthophosphate, chloride, fluoride, bicarbonate, and 25 major/trace elements analyzed by inductively coupled plasma‐mass spectrometry (ICP‐MS). The presence of these constituents in this type of water was investigated considering recent concerns about their quality and the lack of trace element information on the manufacturer labels. The analytical results obtained in this study were compared to the European Union (EU) norms, labeled values on bottles, as well as values from the literature. Results of this study have shown that Turkish CNMWs may contain high concentrations of sulfite, which is a known allergen, especially for chronic asthmatic population. CNMWs surveyed in this study have also appreciable amounts of fluoride (>1.5 mg L^?1) that may have detrimental effects on health of children. The EU standards for As, Ba, Mn, and Ni were exceeded in seven CNMWs classified as “high mineral”. Compared to similar type of bottled waters from Europe and North America, CNMWs from Turkey generally contained higher elemental concentrations.     

Dissolved Organic Carbon in Groundwater Overlain by Irrigated Sugarcane

Elevated dissolved organic carbon (DOC) has been detected in groundwater beneath irrigated sugarcane on the Burdekin coastal plain of tropical northeast Australia. The maximum value of 82 mg/L is to our knowledge the highest DOC reported for groundwater beneath irrigated cropping systems. More than half of the groundwater sampled in January 2004 (n = 46) exhibited DOC concentrations greater than 30 mg/L. DOC was progressively lower in October 2004 and January 2005, with a total decrease greater than 90% indicating varying load(s) to the aquifer. It was hypothesized that the elevated DOC found in this groundwater system is sourced at or near the soil surface and supplied to the aquifer via vertical recharge following above average rainfall. Possible sources of DOC include organic‐rich sugar mill by‐products applied as fertilizer and/or sugarcane sap released during harvest. CFC‐12 vertical flow rates supported the hypothesis that elevated DOC (>40 mg/L) in the groundwater results from recharge events in which annual precipitation exceeds 1500 mm/year (average = 960 mm/year). Occurrence of elevated DOC concentrations, absence of electron acceptors (O₂ and NO₃^–) and both Fe²⁺ and Mn²⁺ greater than 1 mg/L in shallow groundwater suggest that the DOC compounds are chemically labile. The consequence of high concentrations of labile DOC may be positive (e.g., denitrification) or negative (e.g., enhanced metal mobility and biofouling), and highlights the need to account for a wider range of water quality parameters when considering the impacts of land use on the ecology of receiving waters and/or suitability of groundwater for irrigated agriculture.