Phosphorus In Surface Sediments Research Articles

Bioturbation of Tubificid worms affects the abundance and community composition of ammonia-oxidizing archaea and bacteria in surface lake sediments

To better understand the effects of Tubificid worm bioturbation on ammonia-oxidizing microorganisms in surface lake sediment, sediment-water microcosms with different densities of Tubificid worms were constructed. Clone libraries and real-time PCR were applied to analyze the community composition and abundance of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in surface sediments. The results suggest that bioturbation of Tubificid worms promote the release of nitrogen and phosphorus in surface sediment. The abundance of the bacterial amoA gene was higher than that of the archaeal amoA gene in all groups. Nitrosopumilus (93.7 % identity) was the main AOA in all groups, whereas no Nitrosotalea sequence was detected in the three treatment groups. All AOB in the surface sediments belonged to two populations of β-Proteobacteria subclasses, Nitrosomonas (92.7 % identity) and Nitrosospira (97.8 % identity), except those in the surface sediments of the low-density treatment group, which contained only Nitrosomonas. Moreover, the diversities of AOA and AOB were reduced in Tubificid worms containing microcosms. In conclusion, the bioturbation of Tubificid worms affects the abundance and community composition of ammonia-oxidizing microorganisms in surface sediments.

Nutrient Concentration Distribution in Sediment and Overlying Water at Bukit Merah Reservoir, Perak

Bukit Merah Reservoir (BMR) is the oldest reservoir in Malaysia constructed to supply irrigation water to the Kerian Irrigation Scheme. Depletion of storage capacity due to sedimentation process is the most concerning issue of the reservoir recently. Sediment analysis is also very important when monitoring the substances that appear in the reservoir water. Environmental toxins, like heavy metals and hydrophobic organic components, as well as nutrients such as nitrogen and phosphorus are readily bond to the particulate matter. Factors in the reservoir that affect the particulate matter will aid the distribution of contaminants in the sediments. The contaminants in the sediments could have higher concentrations compared to those found in the overlying water. This means that the sediment plays an important role in the cycling of nutrients and distribution of contaminants in the ecosystem. The objectives of this research are to determine the relationship of nutrient and heavy metal content for sediment and overlying water. Nutrient profile information is provided from sediment sample analysis. Based on the data from the horizontal distribution of surface sediment phosphorus in BMR, it was apparent that the highest concentration occurred in the reservoir inlet from Sungai Kurau catchment area. Phosphorus and nitrogen in BMR have a similar trend of decreasing concentration from upstream to downstream. The phosphorus and nitrogen concentrations of surface sediment were in fact significantly correlated with phosphorus and nitrogen concentrations of surface water because of the high value of determination of correlation (R2). As a conclusion, the deposition of sediments was found to bring along external nutrients. Variability of phosphorus and nitrogen concentrations in the sediment directly affects the quality of water which is very important for irrigation and domestic uses.

Distribution, source and chemical speciation of phosphorus in surface sediments of the central Pacific Ocean

The abundance of five forms of phosphorus (P) in surface sediments from the central Pacific Ocean (4.5–15ºN, 154–143ºW) was determined using a sequential extraction procedure (SEDEX) to examine the distribution and source of different P species. Total P (TP) concentrations ranged from 13.2 to 119µmol-P/g with an average of 48.6±27.4µmol-P/g. Within the TP pool, total inorganic P (TIP) concentrations varied from 11.1 to 121µmol-P/g, while total organic P (TOP) concentrations ranged from undetectable to 4.8µmol-P/g. Inorganic P was generally the predominant form in surface sediments, comprising on average up to 93% of sedimentary TP, leaving <16% as TOP. Among the five P species, the authigenic or CaCO3-bound P and detrital P were the two major P species (comprising on average 43.4±13.5% and 45.7±14.8% of TP, respectively), followed by the refractory organic P, representing 6.7±2.4% of TP. Fe-bound P accounted for 3.3±1.3% of TP, and exchangeable or adsorbed P made up less than 1% of TP. The spatial distribution of different sedimentary P species showed that higher concentrations of detrital P and Fe-bound P were both found at around 11°N, suggesting similar sources for these two P species. Much of the detrital P was derived from atmospheric sources in the study area, where heavy rainfall in the intertropical convergence zone between 3°N and 11°N has been widely reported. Compared with other marine environments, the central Pacific Ocean had relatively higher detrital P, but lower abundance of adsorbed-P and Fe-bound P. These unquine results suggested that most of the labile P could have been released into the water column during its settling from the surface to the seafloor, or that atmospheric inputs of refractory P were an important source for sedimentary P, accounting for an average of 63% of the TP, in the central Pacific Ocean. High proportions of authigenic P in deep-sea sediments, on the other hand, implied that oceanic sediments are an important sink for reactive P species. Relatively lower OC/Org-P and OC/Preact ratios suggested a higher sedimentary burial for Org-P and/or attested the importance of detrital P derived from atmospheric sources in the central Pacific Ocean.

Effects of aeration modes on transformation of phosphorus in surface sediment downstream of a municipal sewage treatment plant

This work was devoted to investigating the long-term cumulative effect of municipal sewage treatment plant (STP) effluents on the sediments, near the plant outlet, in Yunliang River in Nanjing, China. Laboratory experiments were performed to assess the effect of different aeration modes on the migration and distribution of phosphorus (P) in the sediments. The field investigation showed that the concentrations of organic matter, different P fractions, dehydrogenase activity and alkaline phosphatase activity in sediments near the STP outlet were higher than those in the upstream site. The results of laboratory studies documented that the retention of P in sediments mainly depended on the characteristics of sediments. Collectively, long-term intermittent aeration accelerated the conversion of parts of organic phosphorus to occluded Fe–P due to that Fe2+ were oxidized to Fe3+ gradually, inactivating the sediments P, which preventing P release completely even in the case of anoxic conditions. Compared with aerating to water, aerating to sediments was more effective on transferring total phosphorus and dissolved inorganic phosphorus (DIP) in overlying water to sediments. Additionally, microbial enzymes activity was directly related to the concentrations of DIP, indicating that enzymes activity could serve as sensitive indicators of nutrient dynamics in water ecosystems.

Impact of harbour, industry and sewage on the phosphorus geochemistry of a subtropical estuary in Brazil

The distribution of different forms of phosphorus in surface sediment from 17 sites were investigated by SEDEX method. The sites were divided into three sectors: Santos Channel (SC – influenced by harbour, fertilizers plants and phosphogypsum mountains), São Vicente Channel (SVC– domestic waste) and Santos Bay (SB – sewage outfall). The average percentage of each P fraction of the surface sediments in this region followed the sequence P–Fe (38%)>Porg (27%)>Pexch (13%)>Detrital – P (12%)>Auth – P (10%). Ptotal varied from 3.57 to 74.11μmolg−1 in both seasons. In SVC, Pexch ranged from 13% to 27% and Porg varied from 12% to 56%. These high percentages of Pexch/Ptotal (greater than 20%) may be related to low oxygen resulting from oxygen consumed by intensive organic matter decomposition as well as the salty water that leads to cation and anion flocculation. Also, the possibility of an influence related to the industrial source of Pexch is not ruled out. No significant seasonal differences were found among sites, except for sewage outfall, with changing in the grain size and hence, the P geochemistry. During the summer in the sewage outfall station, Porg represented 37% of Ptotal, which decreased to 13% in the winter. These results suggest that high percentages of organic phosphorus cannot be attributed only to autochthonous and allochthonous organic matter, but also to detergents and/or domestic waste. In contrast, spatial differences among sectors were observed, with the highest values of each fraction associated with sites near industrial and domestic waste activities.

Characteristics, distribution and ecological risk assessment of phosphorus in surface sediments from different ecosystems in Eastern China: A 31P-nuclear magnetic resonance study

Surface sediments in different ecosystems (lake, river, reservoir, estuary and wetland) in Eastern China were extracted with NaOH–EDTA, and the extracts were analyzed by 31P-NMR to reveal the phosphorus (P) species distribution. The P release risk was also assessed by sorption experiments. The river sediments accumulated significant amounts of P compared with other sediments. The organic phosphorus (Po) concentration in the estuarine sediment was lower than that in other sediments. Two P compounds classes (phon-P and mono-P) and five P compounds were detected in the sediments. Ortho-P (83.3–97.6%) was the dominant P compounds and mono-P (1.1–18.0%) were the dominant Po compounds classes, while smaller amounts of DNA-P (0–4.1%), pyro-P (0–4.0%) and lipid-P (0–0.8%) were found in the surface sediment. Poly-P and phon-P were detected only in site 11 (wetland), site 10 (wetland) and 11, respectively. The ERI values, as a measure of eutrophication risk, were different in the various sediments, being greater than 25% in sites 1 (river), 3 (estuary) and 4 (estuary), and with values of 26, 59 and 83%, respectively. The Xm and ERI values fitted a power function (RXm-ERI=0.89, p<0.01) and a positive correlation between Xm and OM in the sediment (RXm-OM=0.84, p<0.01) indicated that the chemical–physical conditions play a vital role in controlling P sorption and desorption.

Speciation, bioavailability and preservation of phosphorus in surface sediments of the Changjiang Estuary and adjacent East China Sea inner shelf

The speciation, potential bioavailability and preservation of phosphorus (P) in surface sediments of the Changjiang (Yangtze River) Estuary and adjacent East China Sea (ECS) inner shelf were investigated through the analyses of P fractions and sediment bulk properties. A sequential extraction method (SEDEX) was used to separate and quantify the following six sedimentary P reservoirs: exchangeable P (Ex–P), authigenic P (Au–P), detrital P (De–P), organic P (Or–P), refractory P (Re–P) and Fe-bound P (Fe–P). Total P (TP) in surface sediments ranged from 15.0 to 21.4 μmol g−1 and was highest near the Changjiang river mouth. The average contribution of each form of P to TP was 55.6% (De–P), 17.8% (Re–P), 16.1% (Or–P), 5.5% (Au–P), 2.5% (Ex–P) and 2.5% (Fe–P), respectively. De–P showed relatively higher concentrations in the river mouth and the ECS shelf region, off the Changjiang Estuary. High concentrations of Or–P were found mainly in mud areas showing a similar distribution pattern with silt, sediment surface area (SSA), and total organic carbon (TOC). Re–P was mainly distributed near the estuarine area and the Zhe–Min coast. Bioavailable P (BAP), accounted for 9.5–32.0% of TP (with a mean of 21.2%) and showed a similar distribution pattern to that of Or–P. De–P/SSA and TOC/SSA loadings both decreased with increasing of SSA, while Or–P/SSA loadings varied little with SSA, indicating that Or–P may have reached an adsorption–desorption equilibrium on mineral surfaces. TOC to total organic P (TOP; sum of Re–P and Or–P) ratios less than the Redfield ratio (84 in average) may have indicated efficient remineralization of organic matter in mobile muds of the Changjiang Estuary and adjacent ECS inner shelf. Furthermore, the relatively high TOC/Or–P ratios (72–422 with a mean of 188) likely suggest a higher degree of preferential regeneration of labile Or–P over TOC in sediments.

Geochemical characteristics of phosphorus in surface sediments of two major Chinese mariculture areas: The Laizhou Bay and the coastal waters of the Zhangzi Island

Phosphorus (P) in surface sediments of the Laizhou Bay (LB) and the coastal waters around the Zhangzi Island (ZI) was analyzed. Six forms of P were separated — exchangeable or loosely sorbed P (Ads–P), aluminum-bound P (Al–P), iron-bound P (Fe–P), authigenic apatite plus CaCO3-bound P plus biogenic apatite (Ca–P), detrital apatite plus other inorganic P (De–P) and organic P (OP). The average contents of P in the LB were in the order: De–P>OP>Ca–P>Fe–P>Ads–P>Al–P; in the ZI, the corresponding order was De–P>OP>Fe–P>Ca–P>Ads–P>Al–P. Due to the high nutrient loadings from the surrounding rivers, TP contents in sediments of the LB were higher than in those of the ZI. The potential bio-available P (Ads–P and OP) accounted for 14.7% and 24.2% of TP in sediments of the LB and the ZI, respectively.

Species and Characteristics of Organic Phosphorus in Surface Sediments of Northwest Region of Taihu Lake, Eastern China

Various organic phosphorus species in surface sediments from the northwest area of Taihu Lake, China, were measured using organic phosphorus fractionation scheme and the relationships among total organic carbon and different phosphorus species including total phosphorus (TP), total inorganic phosphorus, total organic phosphorus (TOP), microbial biomass P (Biomass‐Po), fulvic‐associated P (FA‐Po), humic‐associated P (HA‐Po), and residual P were also investigated. The results showed that large amounts of phosphorus were associated by organic matter. Organic phosphorus was the important phosphorus species and accounted for 20–50% of TP. TOP, HA‐Po, and Biomass‐Po concentrations decreased from the northwest to southeast region of the lake on the whole. HA‐Po accounting for 34–46% of TOP displayed an unstable trend and was easier to be transformed to other phosphorus species. FA‐Po was relatively stable and did not directly contribute to internal loading of phosphorus. Significant and positive correlation between HA‐Po and other species indicated that HA‐Po and Biomass‐Po were easier to transform to inorganic phosphorus which could be ingested by aquatic organism directly and responsible for high primary productivity of northwest of Taihu Lake.

Internal phosphorus loadings and fluxes of surface sediments in four seasons in Shanzi Reservoir

对山仔水库沉积物各形态磷的季节性特征以及夏、冬季磷释放速率进行研究.结果表明,该水库表层沉积物含有较丰富的磷,4个季节各采样点表层沉积物总磷含量范围为(521.23±7.60)~(1255.54±11.03)μg/g,夏季各采样断面中总磷含量及各形态磷含量均高于其他季节.表层沉积物磷以无机磷为主,且主要赋存形态为铁/铝结合态磷.活性较大的铁/铝结合态磷和有机磷占总磷量的77%~90%.柱状样模拟实验结果表明:夏季溶解性磷释放平均速率范围在1.66~2.49mg/(m²·d),冬季溶解性磷释放平均速率范围为0.69~1.29mg/(m²·d),夏季各采样点表层沉积物磷释放速率约为冬季的2倍.由于水温分层,夏季沉积物释放的溶解性磷主要滞留在上覆层,但夏季暴雨天气可能导致水温分层破坏,沉积物释放的溶解性磷对水体将产生重要影响;冬季由于水温分层破坏导致上、下水层混合,沉积物释放的溶解性磷被带到上层,对上覆水体水质的影响不容忽视.;Spatial and temporal variations of different forms of phosphorus of the surface sediments of Shanzi Reservoir were analyzed in four seasons. The Standard Measurement and Test (SMT) and the sediment cores incubation were applied for observing the phosphorus releasing flux in the water-sediment interface. The results showed that the reservoir sediments are rich in phosphorus. The loadings of total phosphorus in surface sediments ranged from 521.23±7.60 μg/g to 1255.54±11.03 μg/g in four seasons. The amounts of total phosphorus and other phosphorus forms of all samplings were larger in summer than those in other three seasons. The inorganic phosphorus, the dominant phosphorus form in surface sediments, existed in Fe-bound phosphorus forms. The Fe-bound phosphorus and organic phosphorus occupied for 77% to 90% of the total phosphorus. The average releasing rate of dissolved phosphorus ranged from 1.66-2.49 mg/(m²·d) in summer and 0.69-1.29 mg/(m²·d) in winter. The sediment releasing of dissolved phosphorus mainly occurred in the overlying water in summer due to the water temperature stratification. Water temperature stratification may be destroyed if summer rainstorm came and the dissolved phosphorus releasing from the sediments would have a significant impact on the water quality. The water mixed together due to the water temperature stratification disappearing in winter and the dissolved phosphorus was taken to the top water layer, which could greatly affected the overlying water quality.

Phosphorus speciation in wetland sediments of Zhujiang (Pearl) River Estuary, China

Phosphorus fractions and adsorption-release characteristics of sediments in the Zhujiang (Pearl) River estuary wetland were investigated. Results showed that the total phosphorus (TP) content in surface sediments ranged from 648.9 mg/kg to 1064.0 mg/kg; inorganic phosphorus (IP) was the major fraction of TP and ranged from 422.5 mg/kg to 643.9 mg/kg. Among the inorganic phosphorus, the main fractions were phosphorus bound to Al and Fe (Fe/Al-P), and calcium-bound phosphorus (Ca-P), accounting for 23%–42% and 21%–67% of IP, respectively. The vertical distribution of TP contents were significantly positive correlated with organic phosphorus (Org-P) and Fe/Al-P contents. The bio-available phosphorus contents in vertical sediments varied from 128.6 mg/kg to 442.9 mg/kg, mainly existed in Fe-Al/P fraction, and increased from the bottom to top sediments. The transport of phosphorus in sediment-water interface was controlled by the soil characteristics. The active Fe and Al content was considered as the main factor that determines adsorption capacity in vegetated marsh wetland. The P buffering capacity of the sediments in vegetated marsh wetland was greater than that in mudflat wetland. The potential risk of eutrophication in the study area is high. Reducing terrestrial phosphorus discharge and preventing the sediment Fe/Al-P release to the interstitial water are the possible solutions to reduce the risk of eutrophication in estuary wetlands, and planting vegetation in estuary wetland can also reduce the release of phosphorus in surface sediment.

Fractionation of Phosphorus in Surface Sediments Downstream of a Water Dam in Eastern Algeria

The mobility of phosphorus was examined in sediments sampled downstream Béni Haroun dam located in the northeast of Algeria. Sediment samples were collected in winter and spring 2010. They were characterized by the measurements of pH, electric conductivity, total phosphorus, organic carbon and heavy metals. In addition the infrared analysis was carried out. An analytical procedure involving sequential chemical extractions was used for the partitioning of phosphorus in several fractions. In the first scheme, five sedimentary phosphorus (P) reservoirs were separately quantified: loosely sorbed P, calcium bound P, metal oxides bound P, organic P and refractory P. In the second scheme, the distribution of inorganic phosphorus was estimated after removal of organic matter. The inorganic phosphorus mainly consisted of apatite fraction. The rank order of the different P extracts was the same for the two seasons. The contribution of each fraction was found to follow the order: apatite fraction metals oxides fraction, organic fraction, residual fraction, exchangeable fraction.

Spatial distribution characteristics of phosphorus forms in sediment of Lake Hongfeng, Guizhou Province

选取贵州省红枫湖这一典型的亚深水型人工湖泊作为对象,研究了6个代表性湖区沉积物柱芯磷的赋存形态,结合水体温度和溶解氧现场监测结果,探讨了该类型湖泊沉积物内源磷释放风险.研究结果表明,红枫湖沉积物总磷含量普遍较高,表层沉积物总磷含量均值大于1500 mg/kg,明显高于下部沉积物.NaOH-SRP和rest-P是沉积物磷的主要赋存形态.NH₄Cl-P和BD-P含量表层最高,随深度增加明显降低,rest-P含量在垂向上变化不大.人为活动是造成沉积物总磷及赋存形态空间分布差异的主要原因,工业废水和网箱养鱼活动等大大增加了沉积物NaOH-SRP含量.红枫湖深水湖区底部水温多在14.5~23.5℃之间,随季节变化底部水温差异明显,溶解氧含量通常不高于1.5 mg/L,整体处于季节性缺氧或厌氧状态.以NaOH-SRP为主的沉积物磷赋存形态和深水缺氧环境大大增加了红枫湖沉积物内源磷释放的风险,在未来的研究中亟待加强对该类型湖泊沉积物内源磷释放机制、控制因素及治理措施的研究.;Lake Hongfeng is a man-made deep lake. Phosphorus of sediment samples that were collected from representative six water areas were analyzed. Water temperature and dissolved oxygen were investigated four times in the field by multi-parameter water quality observation analyzer YSI. The results showed that total phosphorus in sediment was generally high. The average value of total phosphorus in surface sediment was more than 1500 mg/kg, significantly higher than that in the bottom sediments. NaOHSRP and rest-P were the main forms of phosphorus in sediment. NH₄Cl-P, BD-P and HCl-P contents decreased with depth, and rest-P contents were stabile in vertical. Human activities (e. g. chemical waste water and artificial fish) greatly increased NaOHSRP contents in sediment. Temperature of bottom water was between 14.5-23.5℃, and the maximum temperature differences was 9.9℃ in different seasons. The bottom water was seasonal anoxic or anaerobic, which may result in changes of sediment phosphorus forms. Risk of endogenous phosphorus release increased due to anoxic condition of sediment-water interface in deep lake.

Phosphorus Fractionation and Bio-availability in Surface Sediments from the Middle and Lower Reaches of the Yellow River

Abstract Species and bioavailability of phosphorus in surface sediments from the middle and lower reaches of the Yellow River were investigated using the sequential extraction method. Sedimentary inorganic phosphorus were fractioned into four forms and the rank order according to the mean concentration of P-fraction in Yellow river was HCl-P > NaOH-P > BD-P > NH4Cl-P. The linear relationship between the sum of BD-P and NaOH-P and the sum of active Fe and active Al content was observed within the twelve sediments investigated (R2=0.66). Moreover, the bio-available phosphorus (BAP) content was estimated by the sum of NH4Cl-P, BD-P, and NaOH-P, viz. BAP = NH4Cl-P + BD-P + NaOH-P. In Yellow River, the BAP contents were ranging from 0.031 mg/g dw (dry weight) to 0.066 mg/g dw, and average 0.050 mg/g dw for all sediment samples. The relative contributions of BAP to inorganic sedimentary phosphorus (IP) range from 41% to 62% (53% on average).

Phosphorus forms and distribution in the sediments of Poyang Lake, China

Abstract The forms and distribution of phosphorus in the sediments of Poyang Lake were studied using chemical extraction methods to understand the potential release and adsorption of phosphorus. The results showed that phosphorus in the sediments mainly consisted of inorganic phosphorous species, including iron bound phosphorus, calcium bound phosphorus, aluminium bound phosphorus and dissolved phosphorus, as well as organic phosphorous species. The spatial distribution of phosphorus species in surface sediments showed a decreasing trend from the outlet to the entrance of Poyang Lake. The content of total phosphorus in the surface sediments ranged from 688.29 to 825.36 mg/kg, and inorganic phosphorous was the major phosphorus species. Iron bound phosphorus was the dominant form of inorganic phosphorous, accounting for greater than 40% of the total phosphorus, while calcium bound phosphorus and aluminium bound phosphorus accounted for more than 20%, and dissolved phosphorus accounted for less than 5%. The content of organic phosphorus in surface sediments was lower, accounting for less than 15%. Total phosphorus was positively correlated with iron bound phosphorus, aluminium bound phosphorus, calcium bound phosphorus and organic phosphorous, while organic phosphorous was positively correlated with iron bound phosphorus and aluminium bound phosphorus, but only weakly related to calcium bound phosphorus. For all six sites, the contents of total phosphorus and phosphorus forms in the core sediments obviously decreased with depth, while they were significantly enriched in the surface sediments. The total phosphorus and phosphorus forms contents were significantly higher in the upper layers and had a tendency to decrease toward the bottom of the core, regardless of the phosphorus species. In addition, the average contents of total phosphorus and various phosphorus forms decreased rapidly with sediment depth from 0-20 cm, and then decreased slightly from 20–30 cm.

Spatial distribution and human contamination quantification of trace metals and phosphorus in the sediments of Chaohu Lake, a eutrophic shallow lake, China

Distinguishing and quantifying anthropogenic trace metals and phosphorus accumulated in sediment is important for the protection of our aquatic ecosystems. Here, anthropogenic proportion and potential sources of trace metals and phosphorus in surface sediments of Chaohu Lake were evaluated based on the exhaustive geochemical data. The analysis shows that concentrations of major and trace metals, and phosphorus, displayed significant spatial diversity and almost all elements were over the pre-industrial background value, which should be related to the variations of sediment composition partially. Therefore, conservative element normalization was introduced and calculated enrichment factors (EFs) of the elements were referenced highlighting the human contamination. EFs of the major and trace metals, except Zn, Pb, and Cu, were all nearly 1.0, indicating the detrital origin. The EFs of Zn, Pb, Cu and phosphorus were 1.0-10.4, 1.0-3.8, 1.0-4.9, and 1.0-7.6, respectively, showing moderate to significant contamination. Higher EFs of Zn, Pb and Cu occurred in the mouth areas of Nanfei River and Zhegao River, and they decreased to the lake center in the northwest and northeast lake areas, respectively. We deduced that anthropogenic Zn, Pb, and Cu were mainly from urban and industrial point sources and the non-point sources of atmospheric deposition contributed little to their contamination. The EFs of phosphorus showed similar spatial degradation with that of Zn, Pb, and Cu. Moreover, higher EFs (>1) of phosphorus also occurred in other areas adjacent to the river mouths besides Nanfei River and Zhegao River. This indicated that the non-point agricultural source may also be responsible for the contamination of phosphorus in Chaohu Lake in addition to the urban sewage sources. Anthropogenic phosphorus was mainly concentrated in the speciation of NaOH-P, which had higher potential biological effects than the detrital proportion. Concentrations of Zn, Pb and Cu surpassed the threshold effect concentrations (TEC) of consensus-based sediment quality guidelines of freshwater ecosystems, especially in the contaminated northwest area of Chaohu Lake. This highlighted the contributions of anthropogenic contamination to the elevated potential biological effects of trace metals. Though there had been no obvious human contamination of Cr and Ni in Chaohu Lake, concentrations were all over the TECs, which may be due to higher background levels in the parent materials of soils and bedrocks in Chaohu Lake catchment.

The Human Pollution Evaluation of Phosphorus in Surface Sediments of Nansihu Lake

Abstract Phosphorus content and its species were studied for the surface of Nansihu Lake. The phosphorus contents in the surface sediment are 465.5-13068.3 mg/kg, with the maximum value in Laoyun River, which was due to the waste water pollution from Jining City. The enrichment factors of organic phosphorus (OP) and NaOH-P are 6.5 and 9.0, respectively. The contents of phosphorus in other surface sediments are relatively lower. The enrichment factors of NaOH-P and OP are 1.0-3.7 and 1.3-6.0, indicating a minor human pollution.

Distribution of organochlorine pesticide residues and potential genotoxicity in surface sediments from Lake Taihu

采用GC-ECD对太湖表层沉积物中的有机氯农药含量进行了定性定量分析.太湖20个采样点均有不同程度的有机氯农药检出,16种有机氯农药总量为4.22-460.99ng/g(dw),北部湖区、湖心区以及沿岸区等均有高值点出现,与沉积物有机质含量、氮磷营养盐含量分布并不一致.检出率最高的有机氯农药组分为DDTs、HCHs.DDTs含量检出顺序为p,p'-DDT﹥p,p'-DDD﹥p,p'-DDE,说明环境中可能仍然具有DDT输入特征;HCHs中α-HCH,γ-HCH检出相当,β,δ-HCH检出较高,主要为早期残留.结合鼠伤寒沙门氏菌/哺乳动物微粒体酶系(Ames)试验研究太湖典型湖区表层沉积物中有机污染物的遗传毒性,初步确定可能的生态风险因子.;The present distribution of organochlorine pesticides(OCPs) in surface sediments from Lake Taihu had been quantitatively analyzed by GC-ECD. OCPs were detected in all 20 samples, and total concentrations for 16 kinds of OCPs components ranged from 4.22 to 460.99ng/g(dw). Not only the northern part but also the center and the edge of the lake had higher concentrations, which was inconsistent with the distribution of organic carbons, nitrogen and phosphorus in surface sediments. DDTs, HCHs were the highest in all the detected compounds of OCPs in 20 samples. In DDTs, the residual level of p,p'-DDT was much higher than p,p'-DDE and p,p'-DDD, which showed there maybe new pollution sources recently. In HCHs, the contents of α-HCH and γ-HCH were similar, while β,δ-HCH had much higher residues caused by earlier use of this compound. The genoxicity of the typical locations were examined by the Ames test, and the genotoxic results were combined with the chemical analysis to determine the most responsible stressers for genotoxicity in the surface sediments of Lake Taihu.

Phosphorus dynamics in a lowland river

Seasonal changes in the concentration of phosphorus and other nutrients along a section of the river Wey in southern England are reported. Measurements of the water chemistry upstream and downstream of a point-discharge together with the analysis of surface bed-sediments indicates the accumulation of phosphorus in surface sediments in the spring and summer followed by a decrease in the autumn and winter. The profiles of soluble reactive phosphorus (SRP) concentration along a stretch of river are modelled by simulating the net loss of SRP using the Elovich equation and a parabolic equation. The model utilizes results from measurements of the uptake of phosphorus by bed-sediments in a laboratory fluvarium channel. The channel was also used to measure the uptake of phosphorus and release from bed-sediments to overlying anoxic water. The measured net loss of SRP in the spring survey is much greater than expected from the uptake by the bed-sediment alone. The net phosphorus uptakes measured in the summer and autumn surveys are much less, and in closer agreement with the simulated data.

Phosphorus fractionation in surface sediments of the Amazon continental shelf

The aim of this study is to separate various fractions of phosphorus in surface sediments of the Amazon continental shelf and compare them with other areas of the Brazilian shelf. Surface sediments were collected from the river-mouth transect (RMT) and open-self transect (OST). The extraction techniques available in the literature have been used to separate the following forms: Fe-PO4, Al-PO4, Ca-PO4, and associated organic matter. The results indicate that the concentrations of phosphorus are uniform in the study area and may be compared with many other nonpolluted environments. Among the inorganic forms, Ca-PO4 is dominant in all the samples, and Fe-PO4 is present in lower concentrations. Al-PO4 is more significant on the Amazon continental shelf than other parts of the Brazilian coast and other coastal environments of the world.