Occurrence and distribution of polycyclic aromatic hydrocarbons in surface microlayer and subsurface seawater of Lagos Lagoon,Nigeria

Polycyclic aromatic hydrocarbons (PAHs) in surface microlayer (SML) and subsurface water (SSW) of Lagos Lagoon were investigated using gas chromatography-electron capture detector (GC-ECD) technique to ascertain their occurrence and spatial distribution, origin, enrichment, and carcinogenicity. Total PAH (ΣPAH) concentrations ranged from 9.10 to 16.20 μg L^?1 in the SML and 8.90 to 13.30 μg L^?1 in the SSW. ΣPAH concentrations were relatively higher in the SML than the underlying SSW samples. The enrichment factors (EFs) of ΣPAHs ranged from 0.76 to 1.74 while the EFs of the individual PAHs varied from 0.50 to 2.09. In general, the EFs values calculated in this study were consistent or slightly less than the EFs reported for similar coastal seawater ecosystems. A correlation between the EFs of fluoranthene and pyrene indicated a positive significant value (R?=?0.9828, p?<?0.0001, n?=?6). Source analyses using the phenanthrene/anthracene and fluoranthene/pyrene ratios indicated the dominance of petrogenic-derived PAHs. Furthermore, enhanced concentrations of BaP (strong carcinogenicity) in SML and SSW samples, which resulted in higher EFs, could pose serious ecological and human health risks.     

Genotoxicity evaluation of water soil leachates by Ames test, comet assay, and preliminary Tradescantia micronucleus assay

Combining genotoxicity/mutagenicity tests and physico-chemical methodologies can be useful for determining the potential genotoxic contaminants in soil samples. The aim of our study was to evaluate the genotoxicity of soil by applying an integrated physico-chemical-biological approach. Soil samples were collected at six sampling points in a Slovenian industrial and agricultural region where contamination by heavy metals and sulphur dioxide (SO₂) are primarily caused by a nearby power plant. The in vitro alkaline version of the comet assay on water soil leachates was performed with Caco-2 and HepG2 cells. A parallel genotoxicity evaluation of the samples was performed by Ames test using Salmonella typhimurium and the Tradescantia micronucleus test. Pedological analyses, heavy metal content determination, and different physico-chemical analyses, were also performed utilizing standard methodology. Water leachates of soil samples were prepared according to standard methods. Since only a battery of biotests with prokaryotic and eukaryotic organisms or cells can accurately estimate the effects of (geno)toxicants in soil samples and water soil leachates, a combination of three bioassays, with cells or organisms belonging to different trophic levels, was used. Genotoxicity of all six water soil leachates was proven by the comet assay on both human cell lines, however no positive results were detected by bacterial assay, Ames test. The Tradescantia micronucleus assay showed increase in micronuclei formation for three samples. According to these results we can assume that the comet assay was the most sensitive assay, followed by the micronucleus test. The Ames test does not appear to be sensitive enough for water soil leachates genotoxicity evaluations where heavy metal contamination is anticipated.     

Different hydrodynamic processes regulated on water quality (nutrients,dissolved oxygen,and phytoplankton biomass) in three contrasting waters of Hong Kong

The subtropical Hong Kong (HK) waters are located at the eastern side of the Pearl River Estuary. Monthly changes of water quality, including nutrients, dissolved oxygen (DO), and phytoplankton biomass (Chl-a) were routinely investigated in 2003 by the Hong Kong Environmental Protection Department in three contrasting waters of HK with different prevailing hydrodynamic processes. The western, eastern, and southern waters were mainly dominated by nutrient-replete Pearl River discharge, the nutrient-poor coastal/shelf oceanic waters, and mixtures of estuarine and coastal seawater and sewage effluent of Hong Kong, respectively. Acting in response, the water quality in these three contrasting areas showed apparently spatial–temporal variation pattern. Nutrients usually decreased along western waters to eastern waters. In the dry season, the water column was strongly mixed by monsoon winds and tidal currents, which resulted in relatively low Chl-a (<5 μg l^?1) and high bottom DO (>4 mg l^?1), suggesting that mixing enhanced the buffering capacity of eutrophication in HK waters. However, in the wet season, surface Chl-a was generally >10 μg l^?1 in southern waters in summer due to halocline and thermohaline stratification, adequate nutrients, and light availability. Although summer hypoxia (DO <2 mg l^?1) was episodically observed near sewage effluent site and in southern waters induced by vertical stratification, the eutrophication impacts in HK waters were not as severe as expected owing to P limitation and short water residence time in the wet season.     

Seasonal and spatial variation of reservoir water quality in the southwest of Ethiopia

This research investigated the spatiotemporal variation of water quality in the Gilgel Gibe reservoir, Ethiopia, using physicochemical water quality parameters. Nonparametric tests and multivariate statistical techniques were used to evaluate data sets measured during dry and rainy seasons. Electrical conductivity (EC), pH, biochemical oxygen demand (BOD₅), total phosphorus (TP), total nitrogen (TN), nitrate (NO₃^?), total dissolved solids (TDSs), and total suspended solids (TSSs) were all significantly different among seasons (Mann-Whitney U test, p?<?0.01). In addition, principal component analysis distinguished dry season samples from wet season samples. The dry season was positively associated with EC, pH, TP, TN, NO₃^?, TDS, and TSS and negatively associated with BOD₅. The wet season was in contrast associated with high values of turbidity, soluble reactive phosphorus (SRP), water temperature, and dissolved oxygen (DO). Within the reservoir, spatial variation was observed for some of the water quality parameters, with significant difference at p?=?<?0.05. Overall, high nutrient concentrations suggest eutrophic conditions, likely due to high nutrient loading from the watershed. Levels of TSS, attributed to inputs from tributaries, have been excessive enough to inhibit light penetration and thus have a considerable impact on the aquatic food web. Our findings indicate that the reservoir is at high risk of eutrophication and siltation, and hence, urgent action should target the planning and implementation of integrated watershed management for this and similar reservoirs in the region.     

Study on phosphorus loadings in ten natural and agricultural watersheds in subtropical region of China

Water eutrophication in subtropical regions of southern China threatens watershed health and is of major concern. However, annual phosphorus (P) loading and its dominant causes are still unclear, especially at the watershed scale. In this study, we investigated dynamic P loadings and associated factors (e.g., land use, livestock production, and runoff depth) in ten watersheds that varied in area from 9 to 5,212 ha in a hilly area of Hunan Province, China. A flowmeter was installed at the outlet of each watershed, and total P (TP) and soluble P (SP) concentrations were monitored periodically from June 2010 to October 2012. The results showed that annual P loadings (APLs) in the ten watersheds ranged from 22.8 to 247.8 kg P/km² and that P loss primarily occurred from April to June of each year during the main rainfall season in the study area. In addition, the average eutrophication (>0.05 mg P/L) ratio for stream waters was 86.7 % during the study period, which was indicative of a potentially serious condition for the local water environments. Annual P loadings were linearly related to livestock density (LD; R?=?0.92, p?<?0.01), whereas the eutrophication ratio of stream water was significantly (p?<?0.05) correlated with LD (R?=?0.61), percentage cropland (R?=?0.71), and percentage forest cover (R?=??0.68). Thus, it is concluded that the control of livestock production has the greatest potential for reducing P loadings in watersheds in this subtropical area. This will be beneficial to the amelioration and protection of local environment.     

Planted floating bed performance in treatment of eutrophic river water

The objective of the study was to treat eutrophic river water using floating beds and to identify ideal plant species for design of floating beds. Four parallel pilot-scale units were established and vegetated with Canna indica (U1), Accords calamus (U2), Cyperus alternifolius (U3), and Vetiveria zizanioides (U4), respectively, to treat eutrophic river water. The floating bed was made of polyethylene foam, and plants were vegetated on it. Results suggest that the floating bed is a viable alternative for treating eutrophic river water, especially for inhibiting algae growth. When the influent chemical oxygen demand (COD) varied from 6.53 to 18.45 mg/L, total nitrogen (TN) from 6.82 to 12.25 mg/L, total phosphorus (TP) from 0.65 to 1.64 mg/L, and Chla from 6.22 to 66.46 g/m³, the removal of COD, TN, TP, and Chla was 15.3 %–38.4 %, 25.4 %–48.4 %, 16.1 %–42.1 %, and 29.9 %–88.1 %, respectively. Ranked by removal performance, U1 was best, followed by U2, U3, and U4. In the floating bed, more than 60 % TN and TP were removed by sedimentation; plant uptake was quantitatively of low importance with an average removal of 20.2 % of TN and 29.4 % of TP removed. The loss of TN (TP) was of the least importance. Compared with the other three, U1 exhibited better dissolved oxygen (DO) gradient distributions, higher DO levels, higher hydraulic efficiency, and a higher percentage of nutrient removal attributable to plant uptake; in addition, plant development and the volume of nutrient storage in the C. indica tissues outperformed the other three species. C. indica thus could be selected when designing floating beds for the Three Gorges Reservoir region of P. R. China.     

Genotoxic effects of water pollution on two fish species living in Karasu River,Erzurum, Turkey

Karasu River, which is the only river in the Erzurum plain, is the source of the Euphrates River (Eastern Anatolia of Turkey). The river is in a serious environmental situation as a result of pollution by agricultural and industrial sewage and domestic discharges. The present study aims to evaluate genotoxic effects of toxic metals in chub, Leuciscus cephalus, and transcaucasian barb, Capoeta capoeta, collected from contaminated site of the Karasu River, in comparison with fish from an unpolluted reference site. Heavy metal concentrations in surface water of the river were determined. The condition factor (CF) was taken as a general biomarker of the health of the fish, and genotoxicity assays such as micronucleus (MN) and other nuclear abnormalities (NA) were carried out on the fish species studied. MN and NA such as kidney-shaped nucleus, notched nucleus, binucleated, lobed nucleus, and blebbed nucleus were assessed in peripheral blood erythrocytes, gill epithelial cells, and liver cells of the fish. A significant decrease in CF values associated with a significant elevation in MN and NA frequencies was observed in fish collected from the polluted sites compared with those from the reference site. Results of the current study show the significance of integrating a set of biomarkers to identify the effects of anthropogenic pollution. High concentrations of heavy metals have a potential genotoxic effects, and the toxicity is possibly related to industrial, agricultural, and domestic activities.     

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

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

Little Egret (Egretta garzetta) as a bioindicator of trace element pollution in Tunisian aquatic ecosystems

The Little Egret, Egretta garzetta, has breeding colonies in the island of Chikly (in the lake of Tunis) and in Thyna saltpans (in the gulf of Gabès), two important Tunisian wetlands that are strongly affected by anthropogenic activity. Here, we used E. garzetta chick feathers for environmental monitoring of breeding grounds of this species. Since trophic ecology is fundamental when interpreting contamination levels, our approach combined both trace-element (Hg, Pb, Cd, and Se) and stable-isotope analysis of ??¹³C, ??¹⁵N, and ??³⁴S. Hg, Se, and ??¹⁵N levels were higher in specimens collected on Chikly than in Thyna. These observations highlight the degree of eutrophication of the lake of Tunis. Yellow-legged gulls (Larus michahellis) breeding in the same areas also feeds in the lake and attains similar concentrations of Hg and Se. In Thyna, egrets and gulls exploit distinct foraging habitats, as demonstrated by stable isotope analysis. The highest Hg and Se concentrations were found in Thyna. This result is consistent with greater exploitation of marine resources from the gulf of Gabès.     

Assessment of water quality based on Landsat 8 operational land imager associated with human activities in Korea

Water pollution such as green algae blooms and eutrophication in freshwater fatally influences both water quality and human society. Water quality issues in the 4 major rivers in Korea, including the Nakdong, have recently become a major concern. For this reason, it is essential to monitor water quality parameters (WQPs) that have a widespread characteristic to ensure maintenance of an effective water management system. The possibility of utilizing remote sensing technology for monitoring water quality on a regional scale has been recently investigated. The main objective of this study is to evaluate potential applications of the Landsat 8 Operational Land Imager (OLI) for estimating water quality in the Nakdong River, Korea. Correlations between Landsat 8 bands and in situ measurements are determined, and water quality models are established for estimating suspended solids (SS), total nitrogen (TN), chlorophyll-a (Chl-a), and total phosphorus (TP). The results demonstrate that WQPs correlated well with band reflectance values from Landsat 8. Band 5 was reasonably correlated with all WQPs, particularly with SS (R?=??0.74) and Chl-a (R?=??0.71). This study constructed multiple regression equations for WQPs based on correlation analysis through band combination and band ratio. The spatial distribution of WQPs in the Nakdong River on October 27, 2013 and May 16, 2014 indicate that the river was nearly eutrophic from human activities. Based on the results, the Landsat 8 OLI may be an appropriate data for estimating and monitoring water quality parameters on a regional scale. However, further validation is required to support the findings of this study.     

上海市水体富营养化及洗涤剂中磷的影响研究

针对上海市水体污染状况进行调查研究,结果表明,上海市主要水体苏州河和黄浦江有机污染日益严重,其中苏州河TP 0.6mg/L、TN 10.06mg/L,黄浦江TP 0.23mg/L、TN 4.03mg/L,超标较严重,存在发生富营养化的条件,根据国内外经验和上海的相关资料估算,洗涤剂中的磷占总磷负荷的6.82％。     

Atmospheric influences on water quality: a simulation of nutrient loading for the Pearl River Basin, USA

Knowledge of water quality conditions is essential in assessing the health of riverine ecosystems. The goal of this study is to determine the degree to which water quality variables are related to precipitation and air temperature conditions for a segment of the Pearl River Basin near Bogalusa, LA, USA. The AQUATOX ecological fate simulation model is used to estimate daily total nitrogen, total phosphorus, and dissolved oxygen concentrations over a 2-year period. Daily modeled output for each variable was calibrated against reliably measured data to assess the accuracy. Observed data were plotted against simulated data for controlled and perturbed models for validation, and stepwise multiple regression analysis was used to quantify the relationships between the water quality and meteorological variables. Results suggest that daily dissolved oxygen is significantly negatively correlated to concurrent daily mean air temperature with a total explained variance of 0.679 (p?<?0.01), and monthly dissolved oxygen is significantly negatively correlated to monthly mean air temperature with a total explained variance of 0.567 (p?<?0.01). Total mean monthly phosphorus concentration is significantly positively related to the previous month's precipitation with a total explained variance of 0.302 (p?<?0.01). These relationships suggest that atmospheric conditions have a strong influence on water quality in the Pearl Basin. Therefore, environmental planners should expect that future climatic changes are likely to alter water quality.     

饮用水消毒副产物基因毒性与致癌性研究进展

简述了饮用水消毒副产物（DBPs）的基因毒性与致癌性的研究进展。从Ames试验、SOS/umu试验、彗星试验、微核试验及一些新颖的致突变试验结果对DBPs基因的毒性，以及从毒理学实验、流行病学研究和致癌风险评估3个方面对DBPs的致癌性进行了分析和总结，以期为今后饮用水DBPs毒性效应及其致毒机理研究提供参考，进而促进饮用水质量管理与立法的发展。     

Organochlorine pesticide residues in sediments from coastal environment of Cantabria (northern Spain) and evaluation of the Atlantic Ocean

This paper documents levels of organochlorine pesticides (OCs) in coastal surface sediments from selected reference sites on the northern Atlantic Spanish coast. One hundred eight samples covering three estuaries in the Cantabrian Coast were sampled in 2006 and analyzed in the finer fraction (<63 ??m) for 19 OCs by gas chromatography with electron capture detector after confirmation by mass spectrometry. Detected organochlorine pesticides were endosulfan ??, endosulfan ??, endosulfan sulfate, hexachlorobenzene (HCB), aldrin, dieldrin, methoxychlor, 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (4,4??-DDE) and 1,1-dichloro-2,2-bis(4-chlorophenyl)ethane (4,4??-DDD). Total OCs concentrations ranged from 1.8 ng g^???1 dry weight (dw) to 3.9 ng g^???1 dw, showing a uniform distribution along the studied area, and being consistent with recorded levels in the literature for coastal sediments in other reference sites with low levels of pollution by OCs along the Atlantic Ocean. Endosulfan, 4,4??-DDD, HCB, aldrin, and dieldrin seemed to be ubiquitous as the legacy of past uses and deposition. OCs concentrations were significantly correlated to organic matter content and particle size distribution. No adverse biological effects derived from these pollutants are expected to take place as it can be concluded from the comparison with the existent marine sediment quality guidelines.     

Utilization of polymerase chain reaction and selective media cultivation to identify Legionella in Taiwan spring water samples

In this study, we investigated the distribution of Legionella in sources of spring water and wastewater throughout Taiwan. Legionella were detected with culture method and PCR method from water samples, combined with molecular methods that allow the taxonomic identification of Legionella species. Factors associated with the distribution of Legionella including the physical?Cchemical and microbiological water quality characteristics were also measured. Legionella were detected in 18 of the 68 samples. Additionally, 16 of the 68 samples analyzed by polymerase chain reaction (PCR) and eight of the 68 samples evaluated using the culture method were found to be positive for Legionella. The Legionella species identified included Legionella pneumophila, unnamed Legionella genotypes, uncultured Legionella spp., and Legionella lytica. Legionella species were found in water with temperatures ranging from 10.0 to 50.6??C and with pH values ranging from 5.59 to 9.32. Significant differences (Mann?CWhitney U test, P?<?0.05) were observed in the presence/absence of Legionella in samples with different pH values when Legionella were detected by the culture method. The results of this survey confirmed that Legionella is ubiquitous in the water of spring recreational areas in Taiwan. Long-term investigations of the occurrence of Legionella in hot spring recreational areas throughout Taiwan are needed.     

Studies on water quality of Sutlej River around Ludhiana with reference to physicochemical parameters

Water quality was determined in the different stretches of the river Sutlej (S₁, S₂, and S₃) for a period of 1 year (November 2006 to October 2007). S₁ was at Ropar Head Works, S₂ at U/S of Budha Nallah at Phillaour, and S₃ was D/S of Budha Nallah in district Ludhiana (Punjab). Relatively low values of TDS, turbidity, BOD, total alkalinity, total hardness, chlorides, nitrates, and phosphates were recorded at S₁ and S₂ as compared to S₃. Heavy metals like Pb, Zn, Cr, and Ni were detected at S₂ and S₃. On the basis of water quality standards given by Central Pollution Control Board, the water quality was at ??A?CB?? at S₁, ??B?CC?? at S₂, and ??D?CE?? at S₃. For the computation of water quality rating and water quality index, nine parameters were considered. The mean values of these parameters were compared with WHO, ICMR, and ISI standards. The water quality index at stations S₁, S₂, and S₃ was 32.84, 51.01, and 132.66, respectively. This clearly indicated that the river water at station S₂ and S₃ was found to be unsafe for human consumption.     

Multivariate Analysis of Interactions Between Phytoplankton Biomass and Environmental Variables in Taihu Lake, China

Phytoplankton variation in large shallow eutrophic lakes is characterized by high spatial and temporal heterogenity. Understanding the pattern of phytoplankton variation and the relationships between it and environmental variables can contribute to eutrophic lakes management. In this study Taihu Lake, one of the largest eutrophic fresh water lake in China, was taken as study area. The water body of Taihu Lake was divided into five regions viz. Wuli bay (WB), Meilian Bay (MB), West Taihu Lake (WTL), Main Body of Taihu Lake (MBTL) and East Taihu Lake (ETL). Concentrations of chlorophyll-a and the related environmental variables were determined in each region in the period 2000–2003. Factor analysis and multivariate analysis were applied to evaluate the interactions between phytoplankton variation and environmental variables. Results showed that the highest average concentrations of TN, TP and Chl-a were observed in WB, followed in a descending order by MB and WTL, and the lowest concentrations of TN, TP and Chl-a were observed in MBTL and ETL. Chl-a and TP concentrations in most regions (except ETL) declined during the study period. It suggested that to some extent the lake was recovering from eutrophication. However, persistent ascending of TN and NH₄–N in all five regions indicated the deteriorating of water quality in the study period. Results of multivariate showed that the relationships between phytoplankton biomass and environmental variables varied among regions. TP illustrated itself a controlling role on phytoplankton in WB, MB, WTL and MBTL according to the significant positive relations to phytoplankton biomass in these regions. Nitrogen could be identified as a limiting factor to phytoplankton biomass in ETL in view of the positive correlations between TN and phytoplankton and between NH₄–N and phytoplankton. Spatial variation of interactions between phytoplankton and environmental parameters suggested proper eutrophication control measures were needed to restore ecological system in each region of Taihu Lake.     

Genotoxicity of the sediments collected from Pearl River in China and their polycyclic aromatic hydrocarbons (PAHs) and heavy metals

The accelerated industrialization and urbanization in the last three decades around the Pearl River Delta within Guangdong Province in China have led to serious concerns about the impacts on the aquatic environment. In the present study, the genotoxicity of the sediments collected from the Pearl River was evaluated by micronucleus (MN) assay with Vicia faba root tip cells, and the 16 EPA priority polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs, including Cr, Cu, As, Se, Cd, Hg, and Pb) in the sediments were determined respectively by GC-MS, inductively coupled plasma mass spectrometry, and inductively coupled plasma atomic emission spectrometry. The results showed that there were significant increases of MN frequencies observed in the sediment-exposed groups, compared with the negative group (P?相似文献   

不同水动力条件对景观水体富营养化模拟过程中藻类演替的影响

采用微宇宙培养法,分析了不同水动力条件(不循环、水循环和泥循环)对微污染景观水体富营养化模拟过程中藻类演替的影响.结果表明,水循环和泥循环使得水体的TP值前期增加后期减少,前期藻类生长主要受TP影响,而后期浊度成了重要的影响因素;水循环引起的TP值减少及蓝藻聚集状态的破坏,导致了藻类的生长明显减缓,但优势种的演化过程却...     

Flame ionization gas chromatographic determination of phthalate esters in water, surface sediments and fish species in the Ogun river catchments, Ketu, Lagos, Nigeria

The detection and quantification of four phthalate esters??dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), and diethylhexyl phthalate (DEHP)??in water, sediment, and some fish species were carried out using flame ionization gas chromatography. The samples were collected from the Ogun river catchments, Ketu, Lagos. The DMP was not detected in the water and fish samples but was detected in sediments collected from four of the six sampling sites. The concentration of DEP, DBP, and DEHP in the fish species ranged from 320.0?C810.0, 380.0?C1,080.0, and 40.0?C150.0 ??g/kg in Tilapia sp.; 310.0?C860.0, 400.0?C1,170.0, and 40.0?C110.0 ??g/kg in Chrysichthys sp.; and 320.0?C810.0, 400.0?C3,970.0, and 30.0?C300.0 ??g/kg (DEHP) in Synodontis sp., respectively. The differences in fish phthalate levels are not statistically significant at p?<?0.05, an indication that phthalate esters accumulation is not fish species dependent. The DEP, DBP, and DEHP values recorded are considerably higher than the maximum allowed concentrations for drinking water prescribed by the US Environmental Protection Agency. The phthalate pollution index and biosediment accumulation factor values were also calculated.