Load In Water Research Articles

137Cs in irrigation water and its effect on paddy fields in Japan after the Fukushima nuclear accident

There is concern that radiocesium deposited in the environment after the accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP) in March 2011 will migrate to paddy fields through hydrological pathways and cause serious and long-lasting damage to the agricultural activities. This study was conducted in the Towa region of Nihonmatsu in the northern part of Fukushima Prefecture, Japan, (1) to quantify 137Cs in stream water used to irrigate paddy fields by separating the dissolved and particulate components in water samples and then fractionating the particulate components bonded in different ways using a sequential extraction procedure, and (2) to determine the amounts of radiocesium newly added to paddy fields in irrigation water relative to the amounts of radiocesium already present in the fields from the deposition of atmospheric fallout immediately after the FDNPP accident. Three catchments were studied, and the 137Cs activity concentrations in stream water samples were 79–198mBqL−1 under stable runoff conditions and 702–13,400BqL−1 under storm runoff conditions. The residual fraction (F4, considered to be non-bioavailable) was dominant, accounting for 59.5–82.6% of the total 137Cs activity under stable runoff conditions and 69.4–95.1% under storm runoff conditions. The 137Cs newly added to paddy fields in irrigation water only contributed 0.03–0.05% of the amount already present in the soil (201–348kBqm−2). This indicates that the 137Cs inflow load in irrigation water is negligible compared with that already in the soil. However, the contribution from the potentially bioavailable fractions (F1+F2+F3) was one order of magnitude larger, accounting for 0.20–0.59%. The increase in the dissolved and soluble radiocesium fraction (F1) was especially large (3.0% to infinity), suggesting that radiocesium migration in irrigation water is increasing the accumulation of radiocesium in rice.

Hard foulers induced crevice corrosion of HSLA steel in the coastal waters of the Gulf of Mannar (Bay of Bengal), India

In the present study an attempt has been made to investigate the relationship between the variations in the fouling assemblage and corrosion behaviour of HSLA steel at three coastal locations in the Gulf of Mannar, India, over a period of 24 months. Oyster fouling was dominant in the Tuticorin open sea, while barnacles were the major foulants in the Tuticorin harbour and Mandapam. The fouling load in the Tuticorin waters was higher when compared to the Mandapam waters. The corrosion rates decreased progressively with the immersion time at all three test locations. In the Tuticorin open sea, the corrosion rates were higher when compared to the other two locations throughout the study period. The surface of the coupons was characterized by crevices beneath the hard foulers in the Tuticorin harbour and Mandapam, whereas in the Tuticorin open sea, the coupons experienced crevices of a tunneling nature. The percentage of the loss of the tensile strength increased with time at all the test locations.

연안의 부유물 이동 측정 장치 개발과 현장 적용

Transport of bed load and suspended particle in coastal waters is main factor causing change in shoreline, and effective measurement method and appropriate equipment is required. To measure bed load and suspended particle transport an equipment was designed and manufactured, and it was applied in the field. The equipment consists of four main elements, body supporter, bed load and suspended particle sampler, sampler support and lock. Eight samplers were installed along the circumference of each supporter, and each sample is a 45-degree intervals. The field experiment was done once along Gyeongpo beach in August 2013. This note described the design and function of the equipment and results of field experiments.

Algal Biomass as Potential Biosorbent for Reduction of Organic Load in Gray Water and Subsequent Reuse: Effect on Seed Germination and Enzyme Activity

ABSTRACT Biosorptive treatment using algal biomass of Rhizoclonium riparium was proposed for higher-loading gray water for its effective utilization. A batch sorption study was conducted using composite wastewater having a wide range of initial chemical oxygen demand (COD) values (2400–44,800 mg/L). The study showed an optimum dose of 5 g/L of biosorbent resulted in 96% reduction of COD for wastewater with an initial COD of 10,500 mg/L. The equilibrium isotherm data at different temperatures were fitted to linear and nonlinear isotherms. Biosorption kinetics was studied by various kinetic models. Chemical composition and surface morphology of the biosorbent were characterized by infrared, x-ray diffraction, and scanning electron microscopy techniques before and after biosorption. Applicability of the biosorbent-treated wastewater in agricultural uses was explored by studying the effect of untreated and treated wastewater on the germination of two seeds, i.e., Vigna radiata and Lens esculenta, and subsequently the activity of peroxidase (POD) enzymes were studied to understand the toxicity in plants. The study revealed that compared with seeds treated with different dilutions of untreated wastewater, germination (%) was significantly higher for biosorbent-treated wastewater, with a reduced level of POD activity, indicating positive response of the seeds towards the biosorptive treatment.

Bacteriological status of ashtoum El-Gamil protected area

Survey study was carried out throughout four seasons from four locations representing the whole protected area Ashtoum El-Gamil, Port Said governorate, Manzala Lake concerning the bacterial load in water and fish of this park. The bacterial load in water samples increased by increasing water temperature, the range of total count of bacteria was 0.6×10 6 to 0.2×10 8 /100 ml of water sample in winter and summer respectively. The following bacterial genera were isolated from water samples: Aeromonas, Bacillus, Proteus, Pseudomonas, Streptococcus, S. epidermidis, S. aureus, Micrococcus, Vibrio and E. coli. The predominant microorganisms isolated from water were E. coli, Bacillus spp., Vibrio spp. and Pseudomonas spp. While the total bacterial counts (TBCs) from fish samples obtained on NA media were higher in summer season in all tested organs than other seasons (spring, winter and autumn); also, the high bacterial load was observed in both of gills and intestine comparing with the liver. TBCs were 0.8×10 7 , 0.52×10 7 and 0.13×10 7 cfu / g in gills, intestine and liver, respectively in location No. 3 (bahr kassab) during the summer. The highest TBCs obtained on McCA, MSA, and BHA media were 0.16×10 7 , 0.25×10 7 , and 0.3×10 7 cfu / g of gills in locations No. 1, 1 and 3 during summer, autumn and summer, respectively. The bacterial species isolated also from fish were namely V. cholerae, V. parahaemolyticus, Aeromonas spp., E. coli, Yersinia spp., Proteus, Pseudomonas spp., Micrococcus spp., S. epidermidis, S. aureus and Streptococcus spp. In the pathogenicity test, the most pathogenic bacteria for tilapia fish were Pseudomonas spp., V. cholerae and Aeromonas spp which causing greater than 70, 60% and 60% mortality within 96 hr respectively.

Assif El Mal River: source of human water consumption and a transfer vector of heavy metals

The mining and metallurgical mines that were abandoned with their residues constitute a source of metal pollution affecting the quality of water resources and soil. It is the case of an abandoned mining site Assif El Mal drained by the Assif El Mal River. In fact, these waters are a source of consumption without any treatment by the local population either directly or through their storage in reservoirs. A spatial variation of physicochemical parameters is determined to follow and monitor the behavior of some metals (Pb, Zn, Cu, and Al), from the abandoned mining district, in water and sediment samples along the river till the reservoirs. Also, an assessment of metal contamination level and toxicity of water is studied using the sequential extraction procedure (BCR). The results showed that the metallic load in water exceeds standards for human consumption, especially in the vicinity of the mine and the storage tanks. These levels range from 0.3–17, 0.02–0.05, 0.3–2.8, 0.03–0.1, 2.6–5.1 mg L1, respectively, for Al, Ni, Fe, Pb, and Zn. The potential toxicity of heavy metals in sediment is due to their mobile fraction exchangeable/acid soluble often high (averaging 41 Pb, 52 Zn, and 68% Fe).

Modeling runoff from an agricultural watershed of western catchment of Chilika lake through ArcSWAT

Chilika lake is the biggest lagoon in the Indian Eastern coast and is a source of livelihood for peoples of the coastal region surrounding it mainly through fisheries. However, the deposition of sediments in the lake carried through runoff water from its drainage basins may alter this wetland ecosystem in future. Implementation of appropriate soil water conservation measures may reduce the sediment load in runoff water and thus may protect this lagoon ecosystem. Keeping in view these concerns, runoff water from a selected watershed of western catchment of Chilika lagoon was modeled through ArcSWAT with a purpose to estimate future runoff potential from western catchment. Effective hydraulic conductivity of main channel, base flow alpha factor, curve number corresponding to antecedent moisture content II, and roughness coefficient of main channel were found most sensitive parameters in decreasing order. Nash–Sutcliffe coefficient of predicted monthly runoff was 0.72 and 0.88 during calibration and validation period, respectively whereas root mean squared error of predicted monthly runoff was 54.5 and 66.1 mm, respectively. Modeling results indicated that about 60% of rainfall is partitioned to runoff water, which carry significant amount of sediment load and contributes to Chilika lake.

The impact of periphyton attached on <i>Potamogeton crispus</i> on nitrogen and phosphorus loads in water

通过实验模拟了10组氮、磷负荷对菹草(Potamogeton crispus)生长期和衰亡期茎叶附着物的影响.结果显示:随着水体氮、磷浓度的升高,菹草附着物的叶绿素a(Chl.a)含量、附着有机物量、附着无机物量和附着物总量均增加,在氮、磷浓度最高的T10组(总氮12.0 mg/L,总磷1.0 mg/L),附着物的总量达到高峰,附着物的Chl.a含量为2.005~4.765mg/g(DW),附着有机物的量为29.027~94.886 mg/g(DW),附着无机物的量为176.881~397.750 mg/g(DW),附着物总量为205.909~492.636 mg/g(DW).在菹草的快速生长期、稳定期和衰亡期,附着物的Chl.a含量、附着有机物量、附着无机物量和附着物总量均存在显著差异,均表现为衰亡期 >稳定期 >快速生长期,且在各营养盐浓度下均存在这一趋势.菹草衰亡期附着物的Chl.a含量、附着有机物量、附着无机物量和附着物总量分别为稳定期的1.046~1.826、1.046~1.638、1.029~1.858和1.106~1.717倍,为快速生长期的2.324~4.059、2.323~3.640、2.101~3.792和2.280~3.584倍.结果表明水体氮、磷负荷的增加促进了菹草茎叶附着物的生长和积累,加速了沉水植物衰亡.;To explore the role of periphyton in nutrient cycle in eutrophic shallow lake,the effect of the periphyton attached on Potamogeton crispus on nitrogen and phosphorus loads was examined in a mesocosm experiment conducted in controlled greenhouse.A gradient of ten nutrient concentrations (nitrogen concentrations from 3 to 12 mg/L and phosphorus concentrations from 0.1 to 1.0 mg/L) was established with NH₄Cl,NaNO₃,KH₂PO₄.The results showed that: The content of periphyton chlorophyll-a (Chl.a),organic matter,inorganic matter and total periphyton increased significantly with nitrogen and phosphorus loads increase.The content of periphyton Chl.a,organic matter,inorganic matter and total periphyton reached peak at T10 (TN 12 mg/L, TP 1.0 mg/L) with Chl.a 2.005-4.765 mg/g(DW) periphyton,organic matter 29.027-94.886 mg/g(DW) Potamogeton crispus, inorganic matter 176.881-397.750 mg/g(DW) Potamogeton crispus,and total periphyton 205.909-492.636 mg/g(DW) Potamogeton crispus,respectively.Periphyton Chl.a,organic matter,inorganic matter and total periphyton generally increased with time.Differences in periphyton Chl.a,organic matter,inorganic matter and total periphyton were significant among growth periods, and showed rapid growth period > stable period > decline period.Moreover,this trend occurred at all nutrient concentrations.The periphyton Chl.a,organic matter,inorganic matter and total periphyton of decline period were 1.046-1.826,1.046-1.638,1.029-1.858 and 1.106-1.717 times those of stable period,and were 2.324-4.059,2.323-3.640,2.101-3.792 and 2.280-3.584 times those of rapid growth period.The results above indicated that the periphyton of Potamogeton crispus and its decline were enhanced by elevated nitrogen and phosphorus loads.

진해만 서부 용남·광도해역의 세균학적 수질에 미치는 육상 오염원의 영향

To evaluate the bacteriological water quality in Yongnam-Gwangdo, located in western Jinhae Bay, seawater samples were analyzed using sanitary indicator bacteria at 57 sampling stations. According to survey results from January 2007 to December 2009, the range of the geometric mean and the estimated 90th percentile for coliforms and fecal coliforms in the samples were <1.8-16.5 and 1.8-246.8 MPN/100 mL and <1.8-7.1 and 1.8-74.8 MPN/100 mL, respectively. The samples, including those taken from stations located in Wonmunman, Gwangdo, and Dangdong, showed high levels of microbial contamination caused by the climate and weather patterns in the marine environment. The bacteriological water quality in the area met Korean criteria for a designated shellfish growing area for export and National Shellfish Sanitation Program criteria for an approved shellfish growing area, except at station #49. A total of 24 direct pollution sources were discharged into the shellfish growing area. The radius of impact was calculated for each pollution source to assess the effect on the shellfish growing area. The calculated radius of impact for most of the pollution sources was below 300 m. However, the radius of impact for the combined pollution sources in Kyeonnaeryang was 93-1973 m. There were significant differences between the calculated closed sea area and actual monitoring results. The closed sea area values calculated from the fecal coliform load in drainage water tended to be higher than the actual monitoring results. Tidal currents and environmental factors such as salinity, water temperature, sunlight, and microbiological factors affect the survival of fecal indicator bacteria in seawater.

Rapid monitoring and assessment of pollutional load in dairy waste water

In the present scenario, an attempt was made to develop an ideal device (BOD biosensor) with computer-aided software capable of determining the varying BOD load of dairy waste waters and which facilitates instant monitoring. The shelf life of the developed biosensor was more than 400 days. The results of extensive testing of the developed BOD biosensor on dairy waste water over a period of time demonstrate that the BOD values obtained by the device are statistically correlated with conventional BOD values, irrespective of the varying load of waste water (which might occur as a result of different operations in industry). The developed BOD biosensor shows good reproducibility and repeatability over a period of time. Good correlation (r2 = 0.991) was observed between the values obtained from the developed sensor and conventionally estimated values. The repeatability of the measurements with the BOD biosensor dairy industrial waste water samples (inlet and outlet) was within a percentage deviation of ±10%.

Phosphorus Fertilizer Calibration for Sugarcane on Everglades Histosols

A calibrated soil test for phosphorus (P) fertilizer application to sugarcane (Saccharum spp.) grown on organic soils in southern Florida is an important best-management practice for minimizing P loads in water draining to the Everglades. The current calibration uses water as the soil extractant, which has the limitations of being very sensitive to pH and being most applicable to short-season crops. Phosphorus fertilizer rate studies at six locations (20 total crop years) were analyzed to develop an updated soil-test P calibration for sugarcane on organic soils. Phosphorus extracted with water, acetic acid, and Bray 2 did not consistently relate well to crop response. A new P soil-test calibration for sugarcane is proposed based on Mehlich 3 soil extraction, with a maximum rate of 36 kg P ha−1 with ≤ 10 g P m−3 in preplant soil samples and no P recommended with >30 g P m−3.

Remote monitoring of sediment load in ocean water

Using the Geostationary Ocean Color Imager (GOCI)—the world's first geostationary satellite sensor that can obtain observational data on ocean color every hour during the daytime—scientists are able to remotely monitor the amount of suspended sediment, organic activity, pollutants, and almost any parameter that affects the turbidity and hence the color of the surface of the ocean, in near–real time. Choi et al. compared GOCI images with measurements of suspended sediment load in the Mokpo coastal area along the west coast of Korea. They show that the GOCI color images can reliably monitor suspended sediment load in these coastal waters. They also found that the sediment movement in this region is driven primarily by daily tidal cycles.

Research on correlation between nitrogen compounds, iron and manganese concentrations in drinking water supply systems

A wide range of material sources potentially contribute to contaminant loads in potable water. The ability of water supply systems to act as emission control barriers to tap water micro pollutants, thereby providing environmental benefits in addition to potable water savings, have not been fully explored. This paper investigates the sources, presence and potential fate of a selection of nitrogen micro pollutants in water supply systems. All of the investigated compounds are listed under the requirements to the quality of water intended for human consumption. Significant water quality changes are identified. A wide range of potential treatment trains are available for water treatment and reuse but treatment efficiency data for nitrogen substances is very limited. Nitrogen substances removal through water treatment is following to be predominantly due to ammonium ions, nitrate and nitrite limited concentrations requirement, with only minor contributions to the water supply network. The majority of conventional water treatment plants periodically supply water with nitrogen compounds residual to the potable water distribution system. Hence, it is important to ensure that other nitrogen sources control options (e.g. pipelines materials, and groundwater sources controls) for potable water supply continue to be pursued, in order that nitrogen compounds emissions from these sources are effectively reduced and/or phased out as required under the demands of the requirements to the quality of water intended for human consumption. The aim of this research was to estimate the correlation between nitrogen compounds, iron and manganese concentrations in drinking water supply pipelines in Vilnius (Lithuania) and Warsaw (Poland). First published online:&nbsp;11 Oct 2012

Phosphorus and faecal bacteria in runoff from horse paddocks and their mitigation by the addition of P-sorbing materials

The growing popularity of horse keeping is accompanied by an increase of phosphorus (P) and faecal micro-organisms from outdoor paddocks. We used an indoor rainfall simulation to monitor concentrations of dissolved reactive P (DRP) and faecal coliforms in runoff and percolation water from different paddock footings. Drainage water was also monitored from two paddocks constructed of woodchips. Sand retained more DRP (p&lt;0.0001) and coliforms from percolation water than woodchips. Some of the footings were amended with P-sorbing materials, such as [Ca(OH)2], [Fe2(SO4)3], or Fe-gypsum, to retain DRP. High DRP concentrations (17–18 mg l-1) were observed in runoff from a woodchip footing amended earlier with Ca(OH)2 and in sand footing amended with CaCO3. However, application of Fe-gypsum to woodchips decreased the DRP load in percolation water by 83% compared to the footing without Fe-gypsum. Fe compounds were better than Ca compounds. The decrease in coliforms was usually small due to the modest pH changes in the water.

Coal fly ash interaction with environmental fluids: Geochemical and strontium isotope results from combined column and batch leaching experiments

The major element and Sr isotope systematics and geochemistry of coal fly ash and its interactions with environmental waters were investigated using laboratory flow-through column leaching experiments (sodium carbonate, acetic acid, nitric acid) and sequential batch leaching experiments (water, acetic acid, hydrochloric acid). Column leaching of Class F fly ash samples shows rapid release of most major elements early in the leaching procedure, suggesting an association of these elements with soluble and surface bound phases. Delayed release of certain elements (e.g., Al, Fe, Si) signals gradual dissolution of more resistant silicate or glass phases as leaching continues. Strontium isotope results from both column and batch leaching experiments show a marked increase in 87Sr/86Sr ratio with continued leaching, yielding a total range of values from 0.7107 to 0.7138. For comparison, the isotopic composition of fluid output from a fly ash impoundment in West Virginia falls in a narrow range around 0.7124. The experimental data suggest the presence of a more resistant, highly radiogenic silicate phase that survives the combustion process and is leached after the more soluble minerals are removed. Strontium isotopic homogenization of minerals in coal does not always occur during the combustion process, despite the high temperatures encountered in the boiler. Early-released Sr tends to be isotopically uniform; thus the Sr isotopic composition of fly ash could be distinguishable from other sources and is a useful tool for quantifying the possible contribution of fly ash leaching to the total dissolved load in natural surface and ground waters.

Phosphorus Fertilizer Recommendations for Sugarcane Production on Florida Organic Soils

Much of the sugarcane grown in South Florida is on organic soils in the Everglades Agricultural Area, which is a phosphorus-limited system. Phosphorus loads in drainage water in the Everglades Agricultural Area are an environmental concern, so it is important for sugarcane growers to use best management practices such as soil testing and to follow fertilizer recommendations. This document contains updated UF/IFAS phosphorus fertilizer recommendations for Florida organic soils. This 7-page fact sheet was written by J. Mabry McCray, Ronald W. Rice, and Alan L. Wright, and published by the UF Department of Agronomy, July 2012. SS-AGR-348/SC091: Phosphorus Fertilizer Recommendations for Sugarcane Production on Florida Organic Soils (ufl.edu)

Presence and fate of manganese substances in drinking water supply systems

A wide range of material sources may potentially contribute to contaminant loads in the potable water. The ability of water supply systems to act as emission control barriers for tap water micropollutants, thereby providing environmental benefits in addition to potable water savings, have not been fully explored. This paper investigates the sources, presence and potential fate of a selection of manganese micropollutants in laboratory scaled water supply systems. All of the investigated compounds are listed under the European Council Directive 98/83/EC on the quality of water intended for human consumption (1998) and World Health Organization Guidelines for Drinking-water Quality (2004). Significant water quality changes are identified. Hydro-chemical modelling indicates that the removal of manganese substances during water treatment is likely to be predominant due to the EC Directive manganese concentration requirement, with only minor contributions to the water supply network. Manganese compounds are resistant to biodegradation and the majority of conventional groundwater treatment plants periodically supply water with manganese residual to the potable water distribution system. Water treatment is unlikely to act as a comprehensive barrier for emission of manganese compounds. Hence, it is important to ensure that other manganese source control options (e. g. pipeline materials, manganese substance emission, and groundwater source control) for potable water supply continue to be pursued in order that emissions of manganese compounds from these sources are effectively reduced and / or phased out as required under the demands of the European Council Directive 98/83/EC on the quality of water intended for human consumption.

Effectiveness of Copper Sulfate and Potassium Permanganate on Channel Catfish Infected with Flavobacterium columnare

AbstractCopper sulfate (CuSO4) and potassium permanganate (KMnO4) were evaluated for their effectiveness to curtail mortality and decrease bacterial load in fish tissues and water in channel catfish Ictalurus punctatus infected with Flavobacterium columnare, the causative agent of columnaris. Fish (average size, 16.6 g and 13.7 cm) were obtained from a single culture tank undergoing an epizootic of columnaris and were stocked at a density of 30 fish per tank in each of 12 tanks. The study consisted of three treatments (n = 4 replicates per treatment): an untreated control group, a CuSO4‐treated group, and a KMnO4‐treated group. Treatment rates were 2.1 mg/L CuSO4 and 3.0 mg/L KMnO4 and were applied on three consecutive days at 24‐h intervals. Caudal fin, gill, and liver samples were taken from one fish of each replication 24 h after the last treatment for analysis by quantitative real time PCR. A significant improvement in survival was noted among fish treated with CuSO4 (72.7%) compared with the control fish (38.5%) and the KMnO4‐treated fish (52.2%). Survival of the KMnO4‐treated fish was not significantly different from the control. Quantitative PCR indicated a significant reduction of bacteria in the water after the first and second treatments of both therapeutants; no difference was detected in fish tissues. Histological analysis of gill samples 24 h after the last treatment indicated that CuSO4‐treated fish exhibited significantly less gill damage than untreated controls and there was no difference in KMnO4‐treated fish. Copper sulfate therapy significantly improved survival, reduced the number of bacteria in the water, and reduced gill pathologies associated with F. columnare infection in channel catfish.

Mercury bioaccumulation patterns in fish from the Iténez river basin, Bolivian Amazon

The bioaccumulation mechanism expresses an increment of mercury concentration along the lifetime of each individual. It is generally investigated along the age or size range of organisms from a same population. Water chemistry and trophic position are important factors that may influence the emergence of bioaccumulation patterns. In order to detect the influence of these parameters on fish mercury bioaccumulation patterns, we explored the relations between mercury concentration, size and isotopic trophic position of fish populations of six species (three non piscivorous and three piscivorous) in three rivers of the Iténez basin (Bolivia) with different sediment load in water and anthropogenic impact.Fishes of the Iténez basin showed fairly lower mercury contamination in relation to the regional context. They presented lower total mercury concentrations in unperturbed clear water river (average of 0.051μgg−1 for non piscivores; 0.088μgg−1 for piscivores), intermediate values (average of 0.05 and 0.104μgg−1) in unperturbed white water river, whereas the highest values (average of 0.062 and 0.194μgg−1) were found in the perturbed clear water river. Piscivore and invertivore species showed significant positive bioaccumulation patterns in the perturbed river and in the unperturbed white water river. No positive pattern was detected in the unperturbed clear water river. Positive patterns could not be attributed to differences in trophic condition and mean fish mercury concentration between populations. Bioaccumulation seems not to be the main factor to explain increased mercury concentrations in fish from the perturbed river.

Perfluoroalkyl compounds in municipal WWTPs in Tianjin, China—concentrations, distribution and mass flow

Perfluorinated compounds (PFCs) have drawn much attention due to their environmental persistence, ubiquitous existence, and bioaccumulation potential. Wastewater treatment plants (WWTPs) are fundamental utilities in cities, playing an important role in preventing water pollution by lowering pollution load in waste waters. However, some of the emerging organic pollutants, like PFCs cannot be efficiently removed by traditional biological technologies in WWTPs, and some even increase in effluents compared to influents due to the incomplete degradation of precursors. Hence, WWTPs are considered to be a main point source in cities for PFCs that enter the aquatic environment. However, the mass flow of PFCs from WWTPs has seldom been analyzed for a whole city. Hence, in the present study, 11 PFCs including series of perfluoroalkyl carboxylic acids (PFCAs, C4-C12) and two perfluoroalkyl sulfonates (PFASs, C6 and C8) were measured in WWTP influents and effluents and sludge samples from six municipal WWTPs in Tianjin, China. Generation and dissipation of the target PFCs during wastewater treatment process and their mass flow in effluents were discussed. All the target PFCs were detected in the six WWTPs, and the total PFC concentration in different WWTPs was highly influenced by the population density and commercial activities of the corresponding catchments. Perfluorooctanoic acid (PFOA) was the predominant PFC in water phase, with concentrations ranging from 20 to 170 ng/L in influents and from 30 to 145 ng/L in effluents. Concentrations of perfluoroalkyl sulfonates decreased substantially in the effluent compared to the influent, which could be attributed to the sorption onto sludge, whereas concentrations of PFOA and some other PFCAs increased in the effluent in some WWTPs due to their weaker sorption onto solids and the incomplete degradation of precursors. Perfluorooctane sulfonic acid (PFOS) was the predominant PFC in sludge samples followed by PFOA, and their concentrations ranged from 42 to 169 g/kg and from 12 to 68 g/kg, respectively. Sludge-wastewater distribution coefficients (log K(d)) ranged from 0.62 to 3.87 L/kg, increasing with carbon chain length of the homologues. The mass flow of some PFCs in the effluent was calculated, and the total mass flow from all the six municipal WWTPs in Tianjin was 26, 47, and 3.5 kg/year for perfluorohexanoic acid, PFOA, and PFOS, respectively.