Fish Pond Sediments Research Articles

Polychlorinated dibenzo-p-dioxins and dibenzofuran contents in fish and sediment near a pentachlorophenol contaminated site

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in sediment and fish of aqua farms close to a contaminated site of a pentachlorophenol production plant (CPDC-ASS) were investigated. The total PCDD/F I-TEQ level in sediment and fish ranged from 0.725 to 87.9 ng I-TEQ kg-1d.w.-1 and 0.044 to 3.10 pg I-TEQ g-1w.w.-1, respectively, meaning that the CPDC-ASS was a long-term exposure PCDD/F contaminated area. The four dominant congeners in sediment and fish were OCDD, OCDF, 1,2,3,4,6,7,8-HpCDF and 1,2,3,4,6,7,8-HpCDD. The correlated coefficient of total I-TEQ PCDD/F contents between fish and sediment was 0.82 (R2), indicating a positive correlation between exposure to PCDD/Fs in sediment and biota. In addition, the biota-to-sediment accumulation factors (BSAFs) values of low chlorinated PCDD/F congeners such as those of 2,3,7,8-TeCDD for Milkfish and Tilapia were 0.00739 and 0.00593, respectively, which were much higher than those of highly chlorinated congeners. For example, the BSAFs of OCDD for Milkfish and Tilapia were 0.000207 and 0.000277, respectively. A negative relationship of log Kow and log BSAF for PCDD/F congeners was found, and the highest value was observed at approximately Kow= 7.0–7.5. The results of this study provide valuable information for establishing the PCDD/F regulated standard for the sediment of fish ponds.

Characterization of PAHs in surface sediments of aquaculture farms around the Pearl River Delta

The distribution and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of freshwater fishponds and mariculture rafts around the Pearl River Delta (PRD) were investigated. Twenty-one sample sites were chosen, consisting of fifteen freshwater fishponds and six mariculture rafts. The total PAH (∑PAH) concentrations measured in all the sediment samples ranged from 52.7 to 717 ng g −1, with mean of 184 ng g −1. The marine sediment samples contained higher levels of ∑PAH, high molecular weight (HMW) PAHs and carcinogenic PAHs than freshwater sediments ( p<0.05). Principal component analysis/multiple linear regression analysis (PCA/MLRA) indicated that the source of PAHs in freshwater sediment was mainly derived from mixed combustion of coal, wood, and vehicle emission (66.2%). Vehicle emissions and coal combustion were the main sources (52.5 and 47.5% of ∑PAH, respectively) of PAHs contaminated in the marine sediments. The present study indicated that surface sediments of freshwater fishponds and mariculture rafts around the PRD were grossly contaminated by PAHs derived from combustion sources.

The effects of residual tetracycline on soil enzymatic activities and plant growth

A pot trial was carried out to investigate the adverse effects of tetracycline (TC) on soil microbial communities, microbial activities, and the growth of ryegrass (Lolium perenne L). The results showed that the presence of TC significantly disturbed the structure of microbial communities and inhibited soil microbial activities in terms of urease, acid phosphatase and dehydrogenase (p < 0.05). Plant biomass was adversely influenced by TC, especially the roots with a reduction of 40% when compared with the control. Furthermore, TC decreased the assimilation of phosphorus by the plant although the concentration of phosphorus was increased by 20% due to decreased plant biomass. TC seemed to increase the concentration of dissolved organic carbon (by 20%) in soil. The findings implied that the agricultural use of animal manure or fishpond sediment containing considerable amounts of antibiotics may give rise to ecological risks.

Use of fishpond sediment for sustainable aquaculture—agriculture farming

Use of fishpond sediment for sustainable aquaculture—agriculture farming

Seasonal Changes in Bacterial Flora of Fish Pond Sediments in Saudi Arabia

The goal of this study was to monitor the bacterial flora in pond sediments. Culturable bacteria were enumerated and identified from samples taken from pond sediments in Saudi Arabia at sampling times representative of the four seasons. Bacterial numbers (cfu/g) seemed to be highest in summer. Total viable counts (TVC) of bacteria in the pond sediments varied between 5.2±2.7 × 107 to 1.4±2.3 × 108cfu/g in early summer, 6.6±2.4 × 108 to 8.9±2.0 × 109 cfu/g, significantly higher (P < 0.005) in summer, 4.2±2.8 × 107 to 6.3±1.7 × 108cfu/g, significantly lower (P < 0.005) in autumn, and 7.9±1.9 × 105 to 8.6±2.1 × 106 cfu/g in winter. A total of 20 bacterial species were identified from the sediment. The bacteria were predominantly Gramnegative rods (77%). Aeromonas hydrophila was 27%, significantly higher (P < 0.005) in the population. Seasonal temperature variation could account for some of the bacterial population variation. Aeromonas hydrophila, Shewanella putrefaciens, Corynebacterium urealyticum, Escherichia coli, Pseudomonas sp., Vibrio choleraeand Cellulomonas sp. were the common species in all the bacterial populations of different seasons where the first four bacterial species made up most culturable assemblage (prevalence of > 10%). Flavobacterium sp., Micrococcus sp., Streptococcus sp., Burkholderia glumae and Pasteurella sp. were present in some seasons of the year. Pseudomonas fluorescens and Salmonella sp. were present only in winter, where Pasteurella pneumotropica was found only in summer.

Heterogeneity of sediments and settling particles in aerated ponds

A study was conducted in seabass (Dicentrarchus labrax) and oyster (Crassostrea gigas) ponds to assess the levels of heterogeneity of sediments and settling particles. The intensity of sampling to estimate with high accuracy some characteristics will depend on the magnitude of the variation within the population under consideration. Several variables, such as total phosphate (Tot-P), total iron (Tot-Fe), total ammonium nitrogen (TAN), organic carbon (Org-C), total nitrogen (Tot-N) and P fractions were analysed during the rearing period. The box-and-whisker plots were used as graphical/statistical tools to visualize the descriptive statistical characteristics of the data. In the fish pond, the sediments have high concentrations of Tot-P, Tot-Fe and TAN in comparison with the settling particles. The high C/N ratios in the sediments indicate that the organic matter was more highly degraded in comparison with that of settling particles. The iron- and calcium-bound P (CaCO3≈P) represented 23% and 47% of Tot-P respectively in the fish-pond sediments, whereas the Tot-P was essentially under organic form in the settling particles. In the oyster pond, the trapping rate of solids reached 417 g m−2 day−1 under the trestles. The material consisting mostly of oyster rejection products was less degraded. The similarity in the C/N ratios indicated that the organic matter collected under the oyster trestles was not different from that collected out of trestles. We used multivariate analysis to determine the number of samples needed to be taken to represent the C, N and P average amounts. The principal component analysis (PCA) indicates that the CaCO3≈P and Tot-Fe are the key factors to describe the spatial heterogeneity of the fish-pond sediments. However, the analysis gives no indication of the heterogeneity of settling particles. A partition of the studied stations into different classes was performed by the hierarchical ascending classification (HAC). To assess the variability of the sediments and settling particles during the rearing period, one station could be selected from each group for the next sampling. We used a dilution analysis method to evaluate the magnitude of sedimentation and resuspension in the fish pond. The calculated proportion of resuspension relative to the total flux ranged from 71% to 80% in the fish pond. The ranges of Org-C and Tot-N in the resuspension rate were 19–41 and 2.6–6.7 g m−2 day−1 respectively.

Agricultural Uses of Fishpond Sediment and Sustainability of Asian Integrated Farming Systems

Agricultural Uses of Fishpond Sediment and Sustainability of Asian Integrated Farming Systems

Interference of magnesium on zinc adsorption by pond sediment and on zinc accumulation in a freshwater teleost, Labeo rohita (Hamilton)

Two experiments were conducted to evaluate the interference of magnesium on zinc adsorption in freshwater fish pond sediment and zinc accumulation in the freshwater teleost Labeo rohita (Hamilton). The study demonstrated that increasing the concentration of magnesium as magnesium sulfate from 100 to 400mgkg–1 decreased the adsorption of zinc in sediment. The maximum adsorption was found at a concentration of 100mgkg–1 of Mg2+ and the minimum with 400mgkg–1 of Mg2+. This study also demonstrated that the exposure of fish to 0.25mgL–1 of zinc as zinc sulfate with different concentrations of magnesium (100, 200, 300, and 400mgL–1) for 14d resulted in the minimum accumulation of zinc in L. rohita (2.97mgkg–1 dry weight) at 200mgL–1 of Mg2+, while the maximum accumulation (8.47mgkg–1 dry weight) occurred with no magnesium treatment.

The restoration of fish ponds in agricultural landscapes

Fish ponds in central and eastern Europe are artificial lakes of less than 1 ha to several 100 ha in size. Some of them were created around 900 years ago. These fish ponds form an important part of the hydrological system in the landscape; they also serve as water purification systems and sediment traps, provide habitat for many plant and animal species, as well as being used for recreation purposes—but above all, they are dedicated to fish production. The original oligo- or mesotrophic character of these fish ponds has been altered to one of eutrophic or even hypertrophic conditions due to the nature of the intensive management for high fish production, as well as agriculture practices within the catchment area. It can also be due to other uses of fish ponds, such as wastewater recipients. A thick layer of black anaerobic sediment invariably develops and serves as an uncontrolled internal source of nutrients. In order to stop the development of water blooms and restore the lake to reasonable healthy conditions, both the external and internal loading has to be reduced. An example of such a fish pond restoration within the Czech Republic is described. The phosphorus budget of the Vajgar fish pond (40 ha, S Bohemia) was evaluated and the dry matter, organic matter, nutrients, heavy metals and other metals content were estimated in the vertical profile of the fish pond's sediment. A precision suction dredger was designed, constructed, and used for the selective removal of 330 000 m 3 black sediment from the Vajgar fish pond. The sediment was pumped to settling ponds at a distance of 2.5 km. Later, the suction dredger was used for sediment removal from other fish ponds. In one case, 40 000 m 3 of eutrophic sediment was directly applied on an agriculture field. In another case, sediment containing oil products was decontaminated by using a biocatalyst and bacterial culture. Sediment removal from Vajgar fish pond resulted in a temporary negative phosphorus budget (lower concentrations in the outflow than the inflow). The temporary absence of cyanobacteria ( Microcystis sp.) blooms was the result of the removal of the black sediment layer. The improvement of water quality after sediment removal was, however, temporary. A more holistic approach, aimed at the reduction of matter losses from the fish pond's catchment area, is therefore being adopted. The principles of such an holistic approach are described.

Dioxin reservoirs in southern Viet Nam—A legacy of Agent Orange

In the isolated Aluoi Valley of central Viet Nam, very high levels of 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD) were measured in soil, fish fat, duck fat, pooled human blood and breast milk samples collected from A So village between 1996 and 1999. The village was situated on a former military base occupied by US Special Forces between 1963 and 1966. TCDD was a contaminant of the herbicide “Agent Orange”, aerially sprayed in the valley between 1965 and 1970, and stored at the A So base. Measured levels were lower near the sites of two other former US bases in the valley which had been occupied for shorter periods of time. In areas where Agent Orange had been applied by low-flying aircraft, levels of TCDD in soil, food and human samples were elevated, but lower than those near the three former US bases. We confirm the apparent food chain transfer of TCDD from contaminated soil to cultured fish pond sediments to fish and duck tissues, then to humans as measured in whole blood and breast milk. We theorize that the Aluoi Valley is a microcosm of southern Viet Nam, where numerous reservoirs of TCDD exist in the soil of former military installations south of the former demilitarized zone. Large quantities of Agent Orange were stored at many sites, used in ground and aerial applications, and spilled. TCDD, through various forms of soil disturbance, can be mobilized from these reservoirs after decades below the surface, and subsequently, introduced into the human food chain.

Water content, organic carbon and dry bulk density in flooded sediments

Several basic properties of pond bottom soil are shown to be related, a relation that enable to evaluate pond bottom soil characteristics through the determination of one parameter (e.g. soil moisture). In addition, these relationships give some insight into the properties of flooded sediments. Unlike terrestrial soils, made of gas, liquid and solid phases, flooded sediments are made practically of only two phases, liquid and solid. Since all voids are filled with water, it is possible to evaluate soil porosity and bulk density, directly from the moisture content of the soil, a property easily determined. The correlation between bulk density and organic matter was tested in six different systems ( n=868), including rivers and fish pond sediments in Israel, fish pond sediments in Alabama, USA, and Abbassa, Egypt, lake sediments in New Zealand, alpine lake sediments in Colorado, USA, and sea floor sediments from the Northwest African continental slope. Sediment bulk density was inversely related to the organic carbon concentration. The regression for all the data points was: Bulk density ( g/cm 3)=1.776−0.363 Log e OC (R 2=0.70) where OC is the organic carbon concentration (mg/g). The relationship between sediment moisture, bulk density and organic carbon described here can be used as a simple means to estimate the organic content and bulk density of flooded mineral soils by a simple determination of a sediment water content.

Relation between phosphate and organic matter in fish-pond sediments of the Deroua fish farm (Béni-Mellal, Morocco): implications for pond management

An experimental approach of the phosphate exchange across the water–sediment interface in fish ponds of the Deroua farm (Beni-Mellal, Morocco) is needed to understand the phosphate dynamics in these ponds in relation to their water quality. During this study, we conducted experiments to determine the P-fractions of the different pond sediments and to estimate the release from these sediments of phosphate available for algal uptake. We also determined the amount of phosphate needed to saturate the sediments of two different fish ponds under anoxic and oxic conditions. Phosphate release from sediments comes mainly from Fe(OOH)≈P and is more important in ponds lined with sheets. The accumulation of organic matter in sediments favours the installation of anoxic conditions and enhances the phosphate release from CaCO3≈P, labile in these pond sediments. Under experimental conditions, org-P plays a minor role in the P-release. Oxic conditions, to the contrary, have an inhibitory effect on the P-release from sediments. About 80–98% of the P-adsorbed onto different pond sediments was recovered in the inorg-P-fractions. Aeration induces the oxidation of FeS to Fe(OOH) which can adsorb phosphate from solution. Besides, the presence of bacteria in pond sediments was essential to promote phosphate release under anoxic conditions by controlling the oxidation state of iron and the mineralization of the organic matter. Sheet-lined ponds, when insufficiently dried, accumulate a large quantity of organic matter in their sediments. After a decrease in pH, P is released from CaCO3≈P and enhances the phytoplankton productivity responsible for renewed accumulation of organic matter. Org-C concentrations in sediments over 20 mg g−1 d.w. favour the formation of toxic factors (Fe2+, Mn2+, NO2− and H2S) harmful for carp growth. An extended period of drying efficiently enhances the mineralization of organic matter.

Mercury accumulation in freshwater fish with emphasis on the dietary influence

The first part of the study investigated mercury (Hg) concentrations in freshwater fish collected from the Pearl River Delta and Hong Kong. Mercury concentrations observed in freshwater fish and fish pond sediments collected from the Pearl River Delta were 17.5–267 ng/g (dry wt) and 96 ng/g (dry wt)–1.67 μg/g (dry wt), respectively. As to samples collected from Hong Kong, Hg concentrations were 15.8–84.4 ng/g (dry wt) in fish flesh and 57–435 ng/g (dry wt) in sediments. Accumulation of Hg in fish was related to the spatial difference of Hg in sediment. Significant linear relationships were obtained for the concentrations of Hg in grass carp ( r 2=0.51, n=12), big head ( r 2=0.97, n=12) and tilapia ( r 2=0.55, n=24). The second part of the study investigated the dietary influence on the uptake of Hg by different fish species cultured in the wastewater treatment system at Au Tau Fisheries Station in Hong Kong. The effect of feeding habits of the six fish species in Hg accumulation was apparent. The highest levels of Hg were observed in black bass with the value of 56.7 ng/g (dry wt), moderately in big head (33.8 ng/g dry wt), grass carp (26.3 ng/g dry wt) and silver carp (20.8 ng/g dry wt), and the least in common carp (18.9 ng/g dry wt) and tilapia (13.7 ng/g dry wt).

Sequential extractions of inorganic and org-Phosphate from fish pond sediments (Deroua station, Beni Mellal, Morocco) by different fractionation methods

The carp ponds of Deroua station (Beni Mellal, Centre of Morocco) receive a large quantity of fertilizers, particularly urea and triple super phosphate during the entire period of culture. Only a small part of that is necessary to promote an adequate development of phytoplankton, the base of the food chain. A large part of the phosphate added to the ponds is stocked in pond soils and can be released under specific conditions. Although some phosphate is necessary for the development of aquatic populations, too large of an input causes problems. Therefore, knowledge of the external load and the mobility of the internal pool is essential for the purpose of management against eutrophication. In order to assess the inorganic and organic fractions of phosphate present in sediments, different methods of P fractionation were compared. The methods do not give the same results. In the Deroua sediments, calcium-bound phosphate represents the major part of total phosphate between 86% and 91% according to the different methods. The org-Phosphate represents a small part and varies considerably depending on the different methods between 0.87 and 5%. EDTA extractions (Golterman, 1996) have an advantage over other methods such as the Sedex, the Hieltjes &; Lijklema and the Bonzongo procedures.

On the use of micro-electrodes in fish pond sediments

The surface layer of fish pond sediments is characterized by very high microbial activity. Oxygen uptake by the microbes at the sediment surface leaves little oxygen to penetrate the sediment. In marine and freshwater lake sediments, oxygen only penetrated a few millimeters. In this study, oxygen penetration into the sediment layer in fish ponds and simulated fish ponds was measured with an oxygen micro-electrode. Oxygen profiles determined with micro-electrodes showed that oxygen does not penetrate deeper than 1 mm under quiescent conditions in intensive and semi-intensive fish pond sediments. Sediment oxygen consumption (SOD) at approximately 25°C, calculated from measured oxygen profiles, ranged from 45 to 50 mg O 2/m 2 per h. Change in water temperature and the addition of formaldehyde showed that most of the oxygen consumption in the sediment surface layer is related to biological activity. Redox potential profiles of fish pond sediments measured with a micro-platinum electrode, showed reducing conditions conducive to sulfide formation at 2–4 mm below the sediment surface. Nitrate addition to the overlying water poised redox potential above 300 mV to a sediment depth of about 15 mm. Nitrate thus buffered the sediment–water interface against reducing conditions in the sediment and the possible diffusion of toxic reduced end products to the water.

Reclamation of wastewater for polyculture of freshwater fish: fish culture in ponds

A series of eight pilot-scale ponds (Au Tau pond system) were constructed at Au Tau Fisheries Office, Hong Kong Agriculture and Fisheries Department. Water from a polluted river (Kam Tin River) was pre-treated in the first four ponds by providing sedimentation (S1, S2) and aeration (A1, A2). The effluent from A2 was introduced into the latter four ponds (C1–C4) for polyculture of six species of freshwater fish (silver carp, big head, common carp, grass carp, tilapia and black bass) and supplementary fish feed (peanut cake) was provided. All fish (except grass carp) grew to marketable size within one year with a total yearly net yield of 5 t ha −1 yr −1. In addition to the supplied fish feed, fish also fed on the natural food developed in the ponds and fish growth (except common carp and tilapia) was found to be significantly ( p<0.05) correlated with the concentrations of organic matter and nutrients in water. Biological oxygen demand, inorganic N and PO 4 3− were responsible for 60–80% variations of fish growth according to multiple regression analysis, which suggested that organic matter and nutrients in ponds affected fish growth through the food web developed in ponds. The N conversion to fish flesh from total N input was not more than 3.5% which was below the range reported in other studies (5–25%). The total carbon contents in the sediments of fish ponds did not change significantly ( p>0.05), but the significant increase of N ( p<0.05) seemed to be derived from the input of fish feed and algal precipitation.

Sample Selection in Radiocarbon Dating

SUMMARY Archaeologists working on the island of O’ahu, Hawai’i, use radiocarbon dating of samples of organic matter found trapped in fish-pond sediments to help them to learn about the chronology of the construction and use of the aquicultural systems created by the Polynesians. At one particular site, Loko Kuwili, 25 organic samples were obtained and funds were available to date an initial nine. However, on calibration to the calendar scale, the radiocarbon determinations provided date estimates that had very large variances. As a result, major issues of chronology remained unresolved and the archaeologists were faced with the prospect of another expensive programme of radiocarbon dating. This paper presents results of research that tackles the problems associated with selecting samples from those which are still available. Building on considerable recent research that utilizes Markov chain Monte Carlo methods to aid archaeologists in their radiocarbon calibration and interpretation, we adopt the standard Bayesian framework of risk functions, which allows us to assess the optimal samples to be sent for dating. Although rather computer intensive, our algorithms are simple to implement within the Bayesian radiocarbon framework that is already in place and produce results that are capable of direct interpretation by the archaeologists. By dating just three more samples from Loko Kuwili the expected variance on the date of greatest interest could be substantially reduced.

Analysis of Nitrogen, Phosphorus, Organic Matter and Pigments in the Sediments of Fishponds and Their Environmental Significance

通过对鱼塘沉积物中营养盐、有机质及色素在放养前后的测试．对比分析了在人类活动（养殖）的影响下，由于鱼塘水体快速富营养化而引起底质上述指标的变化过程，其中快速沉积环境极有利于沉积色素的保存，具有较好的环境营养状况指示意义，同时有机质、色素和营养盐之间存在着密切的相关关系，这为利用色素方法研究短时间序列环境演变，尤其是在近代人类活动影响下的环境变化提供了一定的依据。;Factors and processes such as intense human activities and rapid eutrophication. controlling the concentrations of organic substances, nutrients and organic pigments in sediments were analyzed before and after fish culturing in four fishponds. Results show that rapid sedimentation rate is more favorable for reservation of pigments that can be a significant indicator for trophic state of water bodies. In the meantime, there are close relations among organic substances, nutrients and organic pigments in sediments. These can be useful in sedimentary environmental explanatioa by way of organic pigments index.

Determination of phosphorus saturation level in relation to clay content in formulated pond muds

An experiment was conducted to determine the amount of P needed to saturate simulated fish pond sediments, formulated to contain six levels of clay (0, 30, 41, 64, 73 and 81% by weight). A series of cylindrical cement tanks were filled to 20 cm depth with the six sediment types and triple superphosphate (TSP) solution was added to reach P saturation in sediment. Results showed that all sediment types reached constant inorganic-P concentration in the upper 5 cm after 12 weeks of TSP application, and P adsorption capacity of sediment increased with increasing clay content. Sediment P adsorption was slower and not significant ( P > 0·05) below 5 cm depth except in the sediment type containing 0% clay. Regression analysis showed that the rate and adsorption capacity of P in sediment are primarily governed by clay content and its dominant minerals. While organic-P and loosely bound-P are commonly deposited in sediment, most inorganic-P is adsorbed by cations to form cation-P complexes. The linear relationship between cation-P saturation level and the percentage of clay in sediment is highly significant ( r 2 = 0·84, P < 0·001) and, therefore, maximum adsorption capacity of cation-P in pond sediment can be approximated by Y = 0·019 X (where Y represents the 100% saturation level in mg P g −1 soil, and X is the percentage of clay in the sediment). In practice, the level of P saturation in sediment can be approximated by the initial cation-P and clay contents in the top 5 cm of pond mud using the equation: P saturation (%) = initial cation-P (mg g −1 soil) × 100/P adsorption capacity (mg g −1 soil).

Spatial and seasonal distribution of heterotrophic bacteria in pond water and sediments under different management practices

AbstractPopulation densities and generation time of heterotrophic bacteria were estimated in water and sediments of fish ponds used for polyculture, monoculture and traditional systems of fish farming over a period of two and a half years. Spatial differences in microbial densities in the ponds were related to the organic loadings of the farm site and farm management. A number of environmental factors such as nitrogen, dissolved organic carbon, bicarbonate and phosphate of water were found to be responsible for the seasonal changes of heterotrophic bacteria in these ponds.