Abstract This study investigated the distributions of polyclic aromatic hydrocarbons (PAHs) in the sediment cores collected from continental shelf of Gaoping submarine canyon. The sediment cores were analyzed for PAHs to reconstruct historical contamination record of these compounds and to find out the possible sources, trends and fluxes. The average concentrations of £U50 and £U16 PAHs ranged from 568 to 816 ng/g and from 169 to 256 ng/g, respectively. Except for sediment cores L10 and L26, the high molecular weight PAHs (4-6 ring PAHs) were found dominant in 1960s-2006, while the low molecular weight PAHs (2-3 ring PAHs) were found dominant before 1960s. Results from diagnostic ratios and hierarchical cluster analysis (HCA) both suggested that sources of PAHs in the cores of southern continental shelf were primarily from petrogenic, while those in the cores of northern continental shelf were from pyrogenic and petroleum combustion. There is a significant increasing of total PAH concentrations between 1930-1950, suggesting that might be an evident during the World War II. Due to increase of importing fossil fuel and the growth of heavy industrials in Gaoping area, the total concentrations of PAHs showed an increasing trend again since 1950s in the core from continental shelf of Gaoping submarine canyon. In addition, during 1990-2006, the total concentrations of PAHs showed a decreasing trend might result from the environmental protection laws. It is noteworthy that in L28 and L29 sediment cores, the increase of total PAH concentrations recorded during 1990-2006 may be due to the dumping of the sludge from dredged Kaohsiung harbor sediments. Comparing with the sediment quality guidelines (SQG), the PAH concentrations in the northern continental shelf sediment samples were higher than the Threshold Effect Level (TEL) value, suggesting there might be an adverse biological effects caused by PAHs. Keywords¡GPolycyclic aromatic hydrocarbons (PAHs), Kaohsiung harbor, Sediment quality guidelines (SQG)

The main purpose of this research was to analyze the distribution and accumulation of metals in sediment cores of Gao-ping Canyon nearby areas. Enrichment factor (EF) and Sediment Quality Guidelines (SQGs) were also used to assess the pollution history, sources and extent of heavy metal pollution. The results revealed that copper and cadmium metal concentrations have not been contaminated significantly; while zinc and lead concentrations reached moderate degree of pollution, which exceeded guidelines of Low-SLG in Ontario and ERL in NOAA. The concentration of lead was higher than most found in Taiwan. Although chromium was found mild polluted, but attention should still be paid as those concentrations exceeded the values of Low-SLG¡BSevere-SLG and ERL. Comparing results from cores in Southern and Northern shelves of Gao-ping Canyon, the trend of heavy metal concentrations in Northern shelf rose gradually but had an apparent downward trend in surface mixed layer; while distinct variation with time was observed in Southern shelf.

The Australian and New Zealand Environment and Conservation Council (ANZECC) and the Agriculture and Resource Management Council of Australia and New Zealand (ARMCANZ) have announced that the 1997 review of the Australian Water Quality Guidelines will include for the first time, consideration of sediment quality guidelines. For this reason, it is timely to review the methods for establishing such guidelines, and the manner in which they could be used in managing the quality of sediments in Australian rivers, lakes and drainage systems. In this thesis, the problem of the development of sediment quality guidelines is introduced and basic questions relating to the development of such guidelines are addressed. The importance of sediment monitoring and sediment quality assessment in aquatic ecosystem management is demonstrated, and the role of sediment quality guidelines in the process of sediment quality assessment is discussed. The arguments considered in this thesis are illustrated by specific reference to the setting and use of sediment quality guidelines for heavy metal contamination. A number of physico-chemical factors (grain size distribution, pH, redox potential, alkalinity and hardness, salinity, organic matter) can affect the bioavailability and toxicity of contaminants in sediments, and these factors may vary spatially and temporally within and between sediment deposits. Changes in physico-chemical conditions as a result of natural or anthropogenic processes may lead to major changes in bioavailability of sediment contaminants. The variability of these physico-chemical factors has ramifications for the way in which sediment quality guidelines are derived and used. Factors affecting the way in which toxicity is measured (test species chosen, toxicological end-point measured, duration of test relative to life-cycle), and toxicity data is interpreted, are also important to the development of useful sediment quality guidelines. All of these factors must be taken into account in deriving sediment quality guidelines for Australian conditions. The large number of factors affecting the sensitivity and efficiency of sediment quality guidelines means that a simple set of numerical guidelines, as has been used in the past, is not appropriate. A multi-step assessment procedure will be required. Methods of setting sediment quality guidelines that have been used by authorities in overseas jurisdictions were reviewed. Advantages and disadvantages of the various methods were compared. None of the methods used overseas has been shown to be applicable to Australian conditions. In the absence of a suitable method for deriving Australian sediment quality guidelines in the short term, the adoption of the Canadian Interim Sediment Quality Guidelines as interim sediment quality guidelines for Australia is recommended. Sediment quality guidelines need to be viewed in the context of the overall environmental management process, of which they form an integral part. The policy background to environmental management in Australia, and the management frameworks that have been put in place to implement the policy, are outlined. The AS/NZS/ISO 14000 series of standards for environmental management systems provides a framework which is consistent with the principles and objectives of environmental management in Australia. It therefore provides an appropriate framework within which to develop and use sediment quality guidelines. Within the broad AS/NZS/ISO 14000 policy, a framework for the development and use of sediment quality guidelines is proposed, which will provide a technically and legally defensible basis for the management of aquatic sediments in Australia, in the short term and long term. The proposed framework involves the setting of Interim Sediment Quality Guidelines for Australia, based on the best scientific knowledge currently available. The framework recognises that the factors affecting the bioavailability and toxicity of sediment contaminants are complex, and that the current level of knowledge of sediment processes is incomplete. Therefore, a conservative approach to setting guidelines is taken, and a highly sensitive guideline based on that used in Canada, is proposed. The framework further recognises that this approach will lead to over protection of the environment in some cases, so a "Decision Tree" approach is taken. The "decision tree" allows the consideration of more complex interactions than can be incorporated into simple numeric guidelines, while attempting to simplify the assessment process. In keeping with the ISO 14000 series of standards for environmental management, the framework also explicitly includes steps designed to ensure that monitoring data are regularly collated, and analysed, and where necessary, guidelines are able to be updated in light of new knowledge gleaned from the review process. The proposed framework is appropriate to, and supportive of, the principles of environmental management as set out in Australian Government policy documents, inter governmental and international agreements, and legislation. It provides a basis for the on-going collection of data suited to increasing our understanding of the factors influencing the behaviour of contaminants in sediments, and thereby lead to continual improvement in sediment quality guidelines for use in Australian conditions.

The river water quality management strategy involves a series of complex inter-disciplinary decisions based on speculated responses of water and sediment quality to changing controls. In the aquatic system a rapid removal of the heavy metals from the water to sediments may occur by settling particles while some of these pollutants can be mobilized by getting accumulated into the biota from the sediments sink. Thus, sediment plays a major role in the determining pollution pattern of aquatic systems. It acts as both carriers and sinks for contaminants, reflecting the history of pollution, and providing a record of catchment inputs into aquatic ecosystems. The Yan Shuei Gang River watershed is one the river watersheds in Kaohsiung City, Taiwan. It is 5-km long, drains a catchment of more than 1,200 ha. Part of the river water is from the domestic drainage areas located in the upper catchment. In Linhai Industrial Parks, there are more than 493 registered industrial factories that discharge their wastewater into the Yan Shuei Gang River. Thus, recent water and sediments quality analysis indicates that the Yan Shuei Gang River is heavily polluted. The major objectives of this study were to (1) perform water quality and sediments sampling and analyses, (2) perform water quality simulation and demonstrates the model application to the Yan Shuei Gang River, (3) assess the water and sediments quality, (4) provide foci for immediate remediation efforts, (5) provide benchmark levels to test outcomes of future remediation efforts, (6) design a novel extraction technique that utilizes a mildly elevated pressure in consecutive cycles with a chelating agent for the sediment slurry. Water quality investigation results show that the biochemical oxygen demand (BOD), ammonia-nitrogen (NH3-N), and suspended solid (SS) average concentrations in water samples of the Salt-water River varied from 10.2 to 194, 8.51 to 18.3, and 7.9 to 19.5 mg/L, respectively. The results of the chemical analysis of the Salt-water River surface sediments showed that the sediments present highly elevated Cd, Cr, Ni, Cu, Pb, Zn and Fe concentrations. Investigation results reveal that sediment samples contained significant amount of iron (up to 3.6%), Cr (up to 66.5 mg/kg), Pb (up to 36.5 mg/kg), Ni (up to 43 mg/kg), and Al (up to 1.8%). All heavy metal concentrations were higher than the world average, sediments average and sediment quality guidelines (SQGs). Although all metals showed varied concentrations, the approaches of factor analysis, normalized enrichment factor (EF), and the geo-accumulation index (Igeo) proposed in this paper were effectively used to differentiate the natural and anthropogenic sources of the metals. Both the EF and Igeo indicated similar anthropogenic contamination degree of the metals. The potential acute toxicity in sediment of Yan Shuei Gang River was observed to be mainly due to Cu contamination. Cu was the major toxicity contributor accounting for 32-46% of the total toxicity in Salt-water River, followed by Zn. The Water Quality Analysis Simulation Program (WASP) model developed by US Environmental Protection Agency (EPA) was selected as a water quality planning tool to perform the water quality evaluation. Modeling results show that the current daily pollutant inputs were much higher than the calculated carrying capacity for nutrients and BOD of the Yan Shuei Gang River. Based on the results from this study, the following remedial strategies have been proposed to minimize the impacts of industry and domestic source pollution on the water quality of Salt-water River: (1) increase the flow by transporting 1 m3/s unpolluted surface water from other sources to dilute the polluted river water, (2) construction of the intercepting systems to effective intercept and transport the untreated wastewater to the wastewater treatment systems. The sediments batch extracted by 150 psi pressure cycles has the most Cu removed rater (70%), much higher than without treatment (55%) or with 90 psi pressure cycles treatment (65%). Pressure-assisted extraction achieves in 60 min the amounts of Cu equal to or exceeding those achieved in 240 min without pressure cycles under the same concentration conditions. This research indicates that the advantages of pressure cycle system are increased process speed, more thorough extraction, and reduced use of the chelating agent. The heightened treatment is explained by sediments aggregate fracturing upon pressure cycles that exposes the contaminants as well as by the chelating agents. The technique is expected to accelerate extraction treatment of a wide range of heavy metal contaminants, and it may provide treatment to dredged and stored contaminated sediments. Experience obtained from this study will be helpful in designing the sediment and river management strategies for other similar river watersheds.

The distribution of butyltin compounds (BTs) in the sediments and seawater, at the river outfalls, fishing ports, shipyards, and industrial zone docks of Kaohsiung Harbor, Taiwan were investigated. Twenty sediment and seawater samples were collected from various locations in the Harbor in 2006, and analyzed for monobutyltin (MBT), dibutyltin (DBT), and tributyltin (TBT). Results showed that the concentration of total BTs varied from 1.5 to 151 ng/g in sediment samples, with TBT being the major component of the sediment samples. This suggests that sediments could be the most possible sink of TBT brought by the sorption mechanism. The concentrations of BTs ranged from 9.7 to 270 ng/L in seawater samples, whereas DBT and MBT, the degradation byproducts of TBT, were mainly the most abundant BT compounds of the seawater samples. This indicates that the abiotic or biotic degradation potential of TBT was significant. Spatially, the highest concentrations of BTs were observed in both water and sediment samples collected from the shipyard and fishing port areas. This indicates that the shipping related activities (e.g., navigation, ship repair, and ship building), would contribute most of BTs in the environment. Results show that the concentrations of degradation products (DBT and MBT) were related closely to temperature, salinity, dissolved oxygen (DO), and chlorophyll-a of the seawater. This implies that seasonal changes of the water parameters controlled the degradation of TBT in seawater. The observed levels of BT compounds in both seawater and sediments were much higher than those required to induce toxic effects on marine organisms suggesting that appropriate TBT control strategies should be taken in Kaohsiung Harbor. Sediment samples were collected from the river outfalls, fishing ports, shipyards, and industrial zone docks of Kaohsiung Harbor, Taiwan to evaluate the distribution of polycyclic aromatic hydrocarbons (PAHs) in sediments. Collected sediment samples from 12 locations were analyzed for 17 different PAHs, organic content, and grain size. The results show that the total PAH concentrations varied from 472 to 16,201 ng/g dry wt, with a mean concentration of 5,764 ng/g dry wt The highest PAH concentrations were from the industrial zone docks situated in south Kaohsiung Harbor, ranging from 8,788 to 16,201 ng/g dry wt Among those sediment samples, the 5-, 6-ring PAHs were predominant PAH congeners in sediments, ranging from 42 to 71%. However, the dominant PAH congeners were 2-, 3-ring PAHs (37 to 42%) collected from steel industrial zone docks. This indicates that the sources for the PAH contamination at steel industrial zone docks were different from the other zones in Kaohsiung Harbor. According to the diagnostic ratios, the possible source of PAHs in the industrial zone dock could be coal combustion while in the other zones it could be petroleum combustion. The total PAH levels were expressed as the total toxic equivalent (TEQcarc). The total TEQcarc varied from 55 to 1,964 ng TEQ/g dry wt. Higher total TEQcarc values were found at industrial zone docks (from 1,404 to 1,964 ng TEQ/g dry wt). As compared with the US Sediment Quality Guidelines (SQGs), the observed levels of PAHs at industrial zone docks exceeded the effects range low (ERL), and could thus cause acute biological damage. However, the lower levels of PAHs at the other zones would not exert adverse biological effects. Results would be helpful in developing strategies for sediment remediation in Kaohsiung Harbor.

Os sedimentos, pela sua capacidade de acumular compostos, têm grande importância na avaliação do nível de contaminação e poluição dos ecossistemas aquáticos continentais. Este trabalho tem como objetivo avaliar a qualidade do sedimento de um reservatório urbano (Reservatório Guarapiranga, SP, Brasil), quanto ao teor de metais fracamente ligados ao sedimento usando valores-guia de qualidade como parâmetro de comparação; e verificar a possível heterogeneidade dos metais contidos neste sedimento em um gradiente espacial horizontal. Foram amostrados onze pontos ao longo do eixo principal do Reservatório Guarapiranga, com a utilização de coletor tipo Ambhül e Bührer, em 05/10/2006 e 27/04/2007. As variáveis analisadas foram: matéria orgânica total, para cálculo do carbono orgânico total (COT); sulfeto volatilizável por acidificação (SVA), metais simultaneamente extraídos (MES), pH, EH, temperatura, oxigênio dissolvido, profundidade e granulometria. Pela relação molar (∑[MES] - [SVA])/ COT, critério de qualidade de sedimento estabelecido pela U.S.EPA, o sedimento não apresentou toxicidade provável à biota, ou seja, os metais presentes não estão biodisponíveis. As concentrações de SVA e de matéria orgânica encontradas no sedimento e as frações granulométricas silte e argila se mostraram como importantes fases complexadoras dos metais. Segundo os Valores-Guia de Qualidade de Sedimento, estabelecidos pelo Conselho Canadense do Ministério do Meio Ambiente (CCME), em outubro, a maioria dos pontos amostrados encontrou-se acima do intervalo com possíveis efeitos adversos à biota (PEL: Probable Effect Level), em relação a concentração de Cd, Cu e Ni; e em abril a maioria dos pontos amostrados apresentou concentrações acima de PEL para Cu e Cr. A maioria dos pontos amostrados teve concentrações dos metais Cd, Cu, Ni e Zn acima do Valor de Referência Regional (VRR) para sedimentos da Bacia do Rio Tietê, em outubro; e concentrações acima de VRR para Cd, Cu, Cr e Zn, em abril. Em relação à heterogeneidade espacial horizontal, pode-se dividir o reservatório em dois compartimentos, que diferem, de acordo com a PCA, quanto aos teores dos metais Cd e Cu e a profundidade, sendo a região com maiores concentrações de metais a que engloba a captação de água para abastecimento público. Os elevados teores de metais, apesar de este trabalho sugerir que não estão biodisponíveis, reforçam a necessidade do contínuo monitoramento não apenas da qualidade do sedimento, mas também da massa de água, principalmente por se tratar de um reservatório destinado ao abastecimento público para 20% da população da cidade de São Paulo. / Sediments are very important in assessing contamination and pollution level in continental aquatic ecosystems, because of their capacity of accumulating compounds. The objective of this project was to asses sediment quality of a tropical urban reservoir (Guarapiranga Reservoir, São Paulo State, Brazil), related to the level of weakly-bounded metals by using different sediment quality guidelines as reference; and to check possible space heterogeneity of these metals in a horizontal space gradient. Eleven sample stations along the main axis of Guarapiranga Reservoir were sampled by means of an Ambhül and Bührer collector, in October/05/2006 and April/27/2007. The variables analyzed were: total organic matter for calculation of the total organic carbon (TOC), acid volatile sulfide (AVS), simultaneously extracted metals (SEM), pH, EH, temperature, dissolved oxygen, depth and granulometry. According the molar relation (∑[SEM] - [AVS])/ TOC, sediment quality guidelines suggested by U.S.EPA, sediment did not show probable toxicity, in other words, metals were not bioavailable. The AVS, organic matter concentrations and clay silt percentiles showed be important phases of metal complexation, in sediment. According to sediment quality guidelines suggested by Canadian Council of Ministers of Environment (CCME), in October, most of sampling stations presented metal concentration above PEL (Probable Effect Level) for Cd, Cu and Ni; and in April, most of sampling stations presented concentration above PEL for Cu and Cr. Most of sampling stations presents Cd, Cu, Ni and Zn concentrations above the Regional Reference Values (RRV) for Tietê River Basin sediments, in October and concentrations above (RRV) for Cd, Cu, Cr and Zn, in April. In relation to space heterogeneity, the reservoir can be divided into two parts, which are different, according PCA, because of Cd and Cu concentrations and depth, being the region with higher concentrations that from where water is taken in for public supply. The high metal levels, eventhoug the present work indicates no- bioavailability, reinforce the necessity of continuous monitoring of sediment and water quality, especially due to the fact that this reservoir is used to supply 20% of the population from São Paulo city.

O Complexo Billings é o maior reservatório de água da Região Metropolitana de São Paulo. Devido a sua importância estratégica e à degradação da qualidade de suas águas e sedimentos, a represa foi e continua sendo alvo de muitas pesquisas. No entanto, os valores-guia da qualidade de sedimentos (VGQS) adotados pelas normas nacionais vigentes, usualmente aplicados nestes estudos, baseiam-se na abordagem canadense Threshold Effect Level/Probable Effect Level (TEL/PEL), e sua interpretação quanto aos efeitos tóxicos podem divergir dos países que as originaram. O objetivo deste trabalho foi avaliar o potencial tóxico de contaminantes orgânicos e inorgânicos na água e nos sedimentos do reservatório Billings por meio da utilização de diferentes VGQS empíricos e teóricos e ensaios ecotoxicológicos. Uma abordagem multi-tarefas foi conduzida através de avaliações em campo e em laboratório envolvendo extensas caracterizações químicas, físicas e toxicológicas ao longo de dez pontos do reservatório. Em cada local, os parâmetros de qualidade da água superficial foram monitorados in situ. Amostras de sedimento integral, água intersticial e superficial foram coletadas para a avaliação das propriedades físicas e químicas nestes locais, como granulometria e carbono orgânico total (COT). Os teores de sulfetos volatilizáveis por acidificação (SVA) e os metais extraídos simultaneamente (MES) foram obtidos nas amostras de sedimento integral, assim como as concentrações totais de metais (Cd, Cr, Cu, Fe, Mn, Ni, Pb e Zn) e contaminantes orgânicos (pesticidas organoclorados e hidrocarbonetos aromáticos polinucleares). Os contaminantes foram então comparados a diferentes linhas de evidências (LDE), dentre elas VGQS empíricos (TEL/PEL, LEL/SEL e VRR), VGQS baseados na teoria do Equilíbrio de Partição (EqP) e ensaios ecotoxicológicos com as espécies Daphnia magna e Hyalella azteca em água superficial e sedimento integral, respectivamente. As concentrações de metais nas águas superficial e intersticial do reservatório foram relativamente baixas e ausentes de efeitos crônicos ou agudos pelos ensaios ecotoxicológicos. Os teores de SVA foram superiores aos de MES quando normatizados pela fração COT. Embora a LDE baseada em EqP tenha sugerido a ausência de toxicidade nos sedimentos do reservatório Billings, a mesma ocorreu nos pontos Braço do Rio Grande e Barragem de Pedreira. Os resultados dos ensaios ecotoxicológicos demonstraram efeitos agudos para Hyalella azteca, com sobrevivência dos organismos de 32,5 ± 6,57% e 45 ± 5,77% nos pontos Braço do Rio Grande e Barragem de Pedreira, respectivamente. Efeitos crônicos também foram observados para a espécie H. azteca em ambos os pontos. Os valores de biomassa individuais dos anfípodas foram afetadas quando comparadas ao Controle (0,072 ± 0,01 mg), com valores de 0,032 ± 0,01 mg e 0,031 ± 0,01 mg no Braço do Rio Grande e Barragem de Pedreira, respectivamente. A utilização dos VGQS empíricos TEL/PEL e os Valores de Referência Regionais demonstraram ser eficazes para predição de efeitos tóxicos, visto que as concentrações dos metais Cu, Cr, Ni, e Zn presentes nos sedimentos superaram o limiar PEL em vários pontos do reservatório, indicando uma alta probabilidade de efeitos adversos à biota, comprovada pelos ensaios ecotoxicológicos. As concentrações dos pesticidas organoclorados mirex e DDT encontram-se acima de TEL, enquanto o DDE, mais persistente, demonstrou uma alta probabilidade de ocorrência de efeitos tóxicos (acima de PEL). Embora o EqP não tenha sido eficaz na predição dos efeitos tóxicos, foi imprescindível para compreender a dinâmica dos metais no reservatório, visto que os elevados teores de sulfetos e COT demonstram ser os responsáveis pelo equilíbrio dos metais neste ambiente. Dessa forma, a combinação de VGQS empíricos e teóricos pode - de maneira não regulatória - ser considerada uma solução efetiva e de baixo-custo para a tomada de decisão sobre locais passivos de contaminação. / The Billings Complex is the largest water-storage facility in the São Paulo Metropolitan Region. Due to its strategic importance and the deterioration in its water quality over time, the Billings reservoir was and remains subject of many researches. However, the sediment quality guidelines (SQGs) adopted in Brazil and usually applied in these studies are based on the Canadian Threshold Effect Level/Probable Effect Level (TEL/PEL) and may not suitably predict ecotoxicological effects. The aim of this study was to evaluate the toxicity of organic and inorganic compounds in the overlying water, pore water and bedded sediments of the Billings reservoir through several SQGs and toxicological tests. A laboratory and field assessment was conducted involving extensive physical, chemical, and toxicological characterizations within ten stations of the Billings reservoir. At each sampling station, water quality parameters (pH, redox, DO, conductivity, turbidity, and temperature) were measured in depth (intervals of 1 meter). Bedded surface sediment, sediment pore water, and overlying water were collected to assess the physical and chemical properties at these sites, such as particle size and total organic carbon (TOC). Sediment samples were analyzed for acid volatile sulfides (AVS) and simultaneously extractable metals (SEM), total metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) and organic contaminants (organochlorine pesticides and semivolatile organic compounds). Empirical (TEL/PEL, RRV, and LEL/SEL) and mechanistic (AVS/SEM) SQGs approaches were applied and compared with 10-d toxicity tests with Daphnia magna and Hyalella azteca for overlying water and bedded sediment, respectively. Metals in the overlying and pore water were at a relatively low concentrations and absent of chronic or acute effects. AVS concentrations was greater then SEM in every station of the reservoir, therefore suggesting the absence of toxicity. However, Hyalella azteca post-exposure survival was affected in both Rio Grande branch and Pedreira Dam stations (32,5 ± 6,57% and 45 ± 5,77%, respectively). Relative growth rates were also affected in both Rio Grande branch and Pedreira Dam stations (0,032 ± 0,01 mg and 0,031 ± 0,01 mg) when compared to Control (0,072 ± 0,01 mg). Empirical (TEL/PEL, RRV, and LEL/SEL) guidelines were more suitable for toxicity prediction. Several stations exhibit metal concentrations for Cu, Cr, Ni, and Zn higher than the Canadian PEL adopted in Brazil. Organic compounds such as mirex and DDT were above TEL. Persistent DDT metabolite p,p\'-DDE were above PEL in both Rio Grande branch and Pedreira Dam stations. Although EqP was not suitable for toxicity prediction, it was important for understanding the role of sulfides and TOC for metal contamination in the reservoir. Therefore, the adoption of both empirically and mechanistic SQGs for sediment quality assessments can provide a more accurate and low cost alternative for sediment management decisions.

Sediment quality guidelines (SQGs) or values (SQVs) are used to assess the potential risk of contaminants in sediment to aquatic organisms, specifically benthic invertebrates. The objectives of this research were to evaluate SQGs derived specifically for use by the uranium industry in Canada, propose alternative SQVs for use at uranium operations in northern Saskatchewan using a novel approach, and investigate the potentially bioavailable fractions of metals in sediment which could become an alternative measurement to the typically used total metal concentrations. The screening-level concentration (SLC) approach has been used in Ontario, Canada, to derive lowest effect levels (LELs) and severe effect levels for use as SQGs. This approach was adopted by the Canadian Nuclear Safety Commission (CNSC) to set guidelines for metals (As, Cr, Cu, Pb, Mo, Ni, Se, U, and V) and radionuclides (Ra-226, Pb-210, and Po-210) in sediment at northern Saskatchewan uranium mining and milling operations. The SLC approach is based on total metal and radionuclide concentrations in sediment, and corresponding benthic invertebrate community composition data for a specific sampling site. In this study, sediment chemistry (total metals and radionuclides) and benthic community data from northern Saskatchewan uranium operations were compiled and examined. Results indicated that the CNSC-derived SQGs had limited relationships to observed effects, or lack thereof, on benthic invertebrate communities near uranium operations in Saskatchewan. On a general basis, the correct alignment of at least one LEL exceedence at an effect site was observed 95% of the time, but on an element-specific basis many of the elements had concentrations at effect sites below their LELs. Furthermore, concentrations of the evaluated elements exceeded at least one LEL at 60% of the no-effect sites. The high number of exceedences of LELs at reference and no-effect sites (false-positives) calls to question the appropriateness of the CNSC-derived SQGs. To address the deficiencies of the SLC approach, a new approach was developed to derive alternative metal SQVs for the uranium industry in northern Saskatchewan that was based on the use of reference and no-effect site field data. Three different sets of NE values were derived using combinations of benthic invertebrate community effect criteria (abundance, richness, evenness, Bray-Curtis index). Additionally, reference (REF) values were derived based solely on sediment metal concentrations from reference sites. In general, NE values derived using abundance, richness, and evenness (NE1 and NE2 values) were found to be higher than the NE values derived using all four metrics (NE3 values). Derived NE values for Cr, Cu, Pb, and V did not change with the incorporation of additional effects criteria due to a lack of influence from the uranium operations on these metal concentrations (i.e., they were generally present at or near background levels). However, a gradient of exposure concentrations was apparent for As, Mo, Ni, Se, and U in sediment which allowed for acceptable exposure levels of these metals in sediment to be defined. The findings from this assessment proposed a set of new, alternate SQVs for use at the uranium industry in northern Saskatchewan. Often, only total metals concentrations are measured in the evaluation of contaminated sediment. However, this measure may over-estimate metal exposure to benthic invertebrates. Using sediment cores collected from near the Rabbit Lake and Key Lake uranium operations, along with a series of mixed-sediments (contaminated and reference sediment), metal bioaccumulation experiments using Chironomus dilutus were conducted in the laboratory. Metal concentrations in extracts from single extractions with either potassium phosphate or hydrochloric acid on wet and dried sediment, pore-water, and whole-sediment were used to evaluate metal bioaccumulation in test organisms. Depending on the metal, pore-water isolated using peepers generally exhibited the best relationship with tissue metal concentrations. Based on this finding, it is suggested that pore-water sampling using peepers (an in-situ dialysis device) be added to environmental sampling programs at Saskatchewan uranium operations so that sediment metal availability to benthic invertebrates can be better assessed. With the eventual development of a larger pore-water metals dataset, SQGs based on pore-water metals concentrations could likely be derived as an alternative to existing SQGs based on total metal concentrations in sediment.

Sediment quality guidelines (SQGs) or values (SQVs) are used to assess the potential risk of contaminants in sediment to aquatic organisms, specifically benthic invertebrates. The objectives of this research were to evaluate SQGs derived specifically for use by the uranium industry in Canada, propose alternative SQVs for use at uranium operations in northern Saskatchewan using a novel approach, and investigate the potentially bioavailable fractions of metals in sediment which could become an alternative measurement to the typically used total metal concentrations. The screening-level concentration (SLC) approach has been used in Ontario, Canada, to derive lowest effect levels (LELs) and severe effect levels for use as SQGs. This approach was adopted by the Canadian Nuclear Safety Commission (CNSC) to set guidelines for metals (As, Cr, Cu, Pb, Mo, Ni, Se, U, and V) and radionuclides (Ra-226, Pb-210, and Po-210) in sediment at northern Saskatchewan uranium mining and milling operations. The SLC approach is based on total metal and radionuclide concentrations in sediment, and corresponding benthic invertebrate community composition data for a specific sampling site. In this study, sediment chemistry (total metals and radionuclides) and benthic community data from northern Saskatchewan uranium operations were compiled and examined. Results indicated that the CNSC-derived SQGs had limited relationships to observed effects, or lack thereof, on benthic invertebrate communities near uranium operations in Saskatchewan. On a general basis, the correct alignment of at least one LEL exceedence at an effect site was observed 95% of the time, but on an element-specific basis many of the elements had concentrations at effect sites below their LELs. Furthermore, concentrations of the evaluated elements exceeded at least one LEL at 60% of the no-effect sites. The high number of exceedences of LELs at reference and no-effect sites (false-positives) calls to question the appropriateness of the CNSC-derived SQGs. To address the deficiencies of the SLC approach, a new approach was developed to derive alternative metal SQVs for the uranium industry in northern Saskatchewan that was based on the use of reference and no-effect site field data. Three different sets of NE values were derived using combinations of benthic invertebrate community effect criteria (abundance, richness, evenness, Bray-Curtis index). Additionally, reference (REF) values were derived based solely on sediment metal concentrations from reference sites. In general, NE values derived using abundance, richness, and evenness (NE1 and NE2 values) were found to be higher than the NE values derived using all four metrics (NE3 values). Derived NE values for Cr, Cu, Pb, and V did not change with the incorporation of additional effects criteria due to a lack of influence from the uranium operations on these metal concentrations (i.e., they were generally present at or near background levels). However, a gradient of exposure concentrations was apparent for As, Mo, Ni, Se, and U in sediment which allowed for acceptable exposure levels of these metals in sediment to be defined. The findings from this assessment proposed a set of new, alternate SQVs for use at the uranium industry in northern Saskatchewan. Often, only total metals concentrations are measured in the evaluation of contaminated sediment. However, this measure may over-estimate metal exposure to benthic invertebrates. Using sediment cores collected from near the Rabbit Lake and Key Lake uranium operations, along with a series of mixed-sediments (contaminated and reference sediment), metal bioaccumulation experiments using Chironomus dilutus were conducted in the laboratory. Metal concentrations in extracts from single extractions with either potassium phosphate or hydrochloric acid on wet and dried sediment, pore-water, and whole-sediment were used to evaluate metal bioaccumulation in test organisms. Depending on the metal, pore-water isolated using peepers generally exhibited the best relationship with tissue metal concentrations. Based on this finding, it is suggested that pore-water sampling using peepers (an in-situ dialysis device) be added to environmental sampling programs at Saskatchewan uranium operations so that sediment metal availability to benthic invertebrates can be better assessed. With the eventual development of a larger pore-water metals dataset, SQGs based on pore-water metals concentrations could likely be derived as an alternative to existing SQGs based on total metal concentrations in sediment.

Os sedimentos, pela sua capacidade de acumular compostos, têm grande importância na avaliação do nível de contaminação e poluição dos ecossistemas aquáticos continentais. Este trabalho tem como objetivo avaliar a qualidade do sedimento de um reservatório urbano (Reservatório Guarapiranga, SP, Brasil), quanto ao teor de metais fracamente ligados ao sedimento usando valores-guia de qualidade como parâmetro de comparação; e verificar a possível heterogeneidade dos metais contidos neste sedimento em um gradiente espacial horizontal. Foram amostrados onze pontos ao longo do eixo principal do Reservatório Guarapiranga, com a utilização de coletor tipo Ambhül e Bührer, em 05/10/2006 e 27/04/2007. As variáveis analisadas foram: matéria orgânica total, para cálculo do carbono orgânico total (COT); sulfeto volatilizável por acidificação (SVA), metais simultaneamente extraídos (MES), pH, EH, temperatura, oxigênio dissolvido, profundidade e granulometria. Pela relação molar (∑[MES] - [SVA])/ COT, critério de qualidade de sedimento estabelecido pela U.S.EPA, o sedimento não apresentou toxicidade provável à biota, ou seja, os metais presentes não estão biodisponíveis. As concentrações de SVA e de matéria orgânica encontradas no sedimento e as frações granulométricas silte e argila se mostraram como importantes fases complexadoras dos metais. Segundo os Valores-Guia de Qualidade de Sedimento, estabelecidos pelo Conselho Canadense do Ministério do Meio Ambiente (CCME), em outubro, a maioria dos pontos amostrados encontrou-se acima do intervalo com possíveis efeitos adversos à biota (PEL: Probable Effect Level), em relação a concentração de Cd, Cu e Ni; e em abril a maioria dos pontos amostrados apresentou concentrações acima de PEL para Cu e Cr. A maioria dos pontos amostrados teve concentrações dos metais Cd, Cu, Ni e Zn acima do Valor de Referência Regional (VRR) para sedimentos da Bacia do Rio Tietê, em outubro; e concentrações acima de VRR para Cd, Cu, Cr e Zn, em abril. Em relação à heterogeneidade espacial horizontal, pode-se dividir o reservatório em dois compartimentos, que diferem, de acordo com a PCA, quanto aos teores dos metais Cd e Cu e a profundidade, sendo a região com maiores concentrações de metais a que engloba a captação de água para abastecimento público. Os elevados teores de metais, apesar de este trabalho sugerir que não estão biodisponíveis, reforçam a necessidade do contínuo monitoramento não apenas da qualidade do sedimento, mas também da massa de água, principalmente por se tratar de um reservatório destinado ao abastecimento público para 20% da população da cidade de São Paulo. / Sediments are very important in assessing contamination and pollution level in continental aquatic ecosystems, because of their capacity of accumulating compounds. The objective of this project was to asses sediment quality of a tropical urban reservoir (Guarapiranga Reservoir, São Paulo State, Brazil), related to the level of weakly-bounded metals by using different sediment quality guidelines as reference; and to check possible space heterogeneity of these metals in a horizontal space gradient. Eleven sample stations along the main axis of Guarapiranga Reservoir were sampled by means of an Ambhül and Bührer collector, in October/05/2006 and April/27/2007. The variables analyzed were: total organic matter for calculation of the total organic carbon (TOC), acid volatile sulfide (AVS), simultaneously extracted metals (SEM), pH, EH, temperature, dissolved oxygen, depth and granulometry. According the molar relation (∑[SEM] - [AVS])/ TOC, sediment quality guidelines suggested by U.S.EPA, sediment did not show probable toxicity, in other words, metals were not bioavailable. The AVS, organic matter concentrations and clay silt percentiles showed be important phases of metal complexation, in sediment. According to sediment quality guidelines suggested by Canadian Council of Ministers of Environment (CCME), in October, most of sampling stations presented metal concentration above PEL (Probable Effect Level) for Cd, Cu and Ni; and in April, most of sampling stations presented concentration above PEL for Cu and Cr. Most of sampling stations presents Cd, Cu, Ni and Zn concentrations above the Regional Reference Values (RRV) for Tietê River Basin sediments, in October and concentrations above (RRV) for Cd, Cu, Cr and Zn, in April. In relation to space heterogeneity, the reservoir can be divided into two parts, which are different, according PCA, because of Cd and Cu concentrations and depth, being the region with higher concentrations that from where water is taken in for public supply. The high metal levels, eventhoug the present work indicates no- bioavailability, reinforce the necessity of continuous monitoring of sediment and water quality, especially due to the fact that this reservoir is used to supply 20% of the population from São Paulo city.