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Ecotoxicology • Ecotoxicological study is a multi-step process, involving: – The entry, distribution and fate of pollutants within the environment; – The entry and fate of pollutants in living (biota) organisms within an ecosystem; and – The harmful effects of the chemical pollutants on the constituents (biotic & abiotic) of ecosystems (which include man). Beyond our toxin trail Is the grave deeper than we thought? Transport and fate Toxin emitted Ecosystem effects Community effects Metabolized and/or stored Ingested Contacts human Population effects Reaches an organ Physiological chain of events Toxicology and Ecotoxicology are similar but not identical • • • • Toxicology Ecotoxicology Absorption Release into environment Distribution Fate and disposition Metabolism Metabolism Elimination No counterpart There are also differences. Toxicology Ecotoxicology • Host defense mechanisms • Individual susceptibility states • Single effects • Cumulative exposure • Bioaccumulation • Bioconcentration (in water) • Biomagnification • Never single effects • Movement between media (air, water) Ecological bases of Ecotoxicology • The basis for determining the effects of contaminants on ecosystem is at organism level • At organism level, response can be: – Acute toxicity causing mortality – Chronically accumulating damage ultimately causing death – Sublethal impairment of various aspects of physiology and morphology – Sublethal behavioral effects – Measurable biochemical changes •At population level, response can be: –Size and dynamics (based on birth rates, death rates, gains, from immigration and losses from emigration) –Cause a reduction or an increase in the natural flowchart of numbers, in the biomass, sex ratio, etc. •At community level, response can be: –species diversity –predator prey relationship, etc •Change in ecosystem –nutrient cycling rates, patterns of nutrient flow, –physical-chemical conditions etc. Understanding ecotoxicology Assessment of Structural Changes changes in species / population structure - appearance/disappearance of an indicator species - number of individuals of a species - biomass of a species - presence or absence of a species Biomass-a quantitative estimate of the total mass of living plant or animal materials changes in community/ecosystem structure - biomass abundance biotic indices (e.g. trophic types) species richness / diversity dominance food chain length/complexity Chemicals of Ecotoxicological interes • They are toxic and in many cases their metabolites are also harmful e.g. DDT & DDE (metabolite of DDT) • They are very stable both chemically and environmentally • Their stability has lead to their persistence and ubiquitous nature in the environment • Almost all chemicals of ecotoxicologigal interest are bioavailable and in most cases undergo bioaccumluation and biomagnification (food chain) Chemical behavior and Bioavailability Bioconcentration (from external environment) Bioaccumulation (from external environment/food ) Biomagnification (at higher tropic level) Bioavailabiltiy The fraction of a chemical that is in an available form to an organism e.g. fish: food, absorption from water Bioconcentration - where the chemical concentration in an organism exceeds the concentration in the surrounding media (i.e. aquatic environment) as a result of exposure through the respiratory surfaces (i.e. gills/dermal surfaces) - not food! Bioconcentration Factor = conc. in organism conc. in ambient medium (usually water) Bioaccumulation - where the chemical concentration in an organism achieves a level that exceeds that in the water/media as a result of chemical uptake through all routes of exposure. Bioaccumulation factor = Conc. in organism Conc. in food (or ingested water) •Bio-accumulation of Cd is higher than most metals as it is assimilated rapidly and excreted slowly •depends on the rate of excretion Biomagnification - where the chemical concentration in an organism achieves a level that exceeds that in the organism’s diet due to dietary absorption. i.e. higher trophic levels accumulate more chemical Biomagnification Factor = Conc. in predator Conc. in prey Factors that influence bioaccumulation •Environmental persistence •Lipophilicity •Biotransformation ECOSYSTEMS: Fate of Metals • The ultimate compartment is the whole planet but compartment can be – individual organism or – as small as single cells – Or even organelles within a cell • Metals are non-biodegradable • However there is the formation and degradation of organometallic compounds e.g. MeHg, Fate of Metals • Certain metals are assimilated by organisms to a greater extent than others • Bio-accumulation of Cd is higher than most metals as it is assimilated rapidly and excreted slowly • Bio-availability is another reason for a high bio-concentration factor in that the chemical in question may be more bioavailable Fate of Metals • pH is very important when it comes to metal bio-availability • Some metals e.g. Al is insoluble at normal to slightly acidic pH but below pH 4.5 its solubility increases dramatically and becomes most important responsible for fish kills in acidified lakes ECOSYSTEMS: Terrestrial • Soils are contaminated – by metals and radioactive isotopes resulting from • industrial, mining or other activity or deposition from agricultural practices such as application of – metal-containing pesticides or – metal-contaminated sewage sludge – or wet or dry deposition from smelting activity, lead-containing car exhaust, atmospheric nuclear weapon testing or accidents such as Chernobyl. ECOSYSTEMS: Terrestrial • Mobility of metals in soils is dictated largely by – clay content – amount of organic matter – pH • In general the higher the clay and/or organic matter content and pH, the more firmly bound are the metals and the longer is their residence time in soil • Acid rain helps in leaching nutrient (magnesium in European soil) from top to lower soil (inaccessible to root system) ECOSYSTEMS: Terrestrial • Contamination of soils by radioactive materials is largely due to nuclear weapon testing (Australian and Nevada deserts) • Accident has also contributed to that e.g. Chernobyl fallout outside the former Soviet Union. • When soils are contaminated organisms living in soils are affected ECOSYSTEMS: Aquatic • The ultimate “sink” for metal is the ocean but difficult to estimate effect on biota due to massive dilution • Effect of metals on biota is much felt in estuaries especially those receiving water from contaminated sites • In estuaries the flow rate diminishes, suspended sediments settled and dissolved metals precipitated • Contaminated water affect organisms living in it Biomarkers A xenobiotically induced alteration in cellular or biochemical components or processes, structures, or functions that is measurable in a biological system or sample. Types of Biomarkers Biomarkers of exposure Biomarkers of effect Biomarkers of susceptibility 1. Biomarkers of exposure Biomarkers of exposure include exogenous chemicals, metabolites, or products of interactions between environmental toxicants and target molecules or cells that are measured in a compartment within an organism (Travis, 1993). Internal dosimeters1. measure the amount of a toxicant or its metabolite present in cells, tissues, or body fluids. Ex. urinary nitrophenol concentration used as a marker for methyl parathion exposure. 2. account for individual differences in absorption and bioaccumulation of the xenobiotic and are relatively easy to measure. The biologically effective dose is the amount of the internal dose necessary to elicit a response or health effect. 2. Biomarkers of Effect Biomarkers of effect are measurable alterations of an organism that can indicate a potential or established health impairment or disease (Travis, 1993). These can include an alteration in a tissue or organ, an early event in a biologic process that is predictive of disease, a health impairment or clinical disease, or a response parallel to the disease process, but correlated with it, and able to predict health impairment. Ex. the change in blood cholinesterase activity after exposure to anticholinesterase organophosphorous pesticides. Nonspecific The induction of mixed function oxidase The formation of DNA adducts Sister chromatid exchange Strand breakage Porphyrin profile alteration Induction of vitellogenin in oviparous vertebrates Immunochanges (immunosupression, hypersensitivity) Biomarkers in order of decreasing specificity Source: Walker et al. Principles of Ecotoxicology (2001) 2nd Edition [DUHS-P] 3. Biomarkers of Susceptibility Biomarkers of susceptibility indicate individual factors that can affect response to an environmental toxicant (Bearer, 1998). They are indicators of inherent or acquired properties of an organism that may lead to an increase or decrease in the internal dose of the xenobiotic or an increased or decreased level of the response resulting from the exposure. Genetic polymorphisms fall into this category of biomarkers. P450 1A1 induction Decreases in conjugated enzymes Inhibit the activity of immune system Biomarker interpretation Species different-ex.P450 induction to integrate multiple chemical exposure across an area with a variety of chemical contaminants Relationship between biomarker and disease pathology To predict disease To predict environmental and genetic risk Toxic Effects • The biochemical (molecular in nature) or physiological (observed at organ and whole organism levels) changes which adversely affect individual organisms’ birth, growth or mortality rates. • Both biochemical and physiological changes could lead to behavioral (whole organism level) changes Example • The pollutant binding to a receptor • Followed by biochemical response at both cellular and organ levels • Leading to physiological responses • Finally, behavioral changes on the individual leading to effects on the population, community and the ecosystem. BEHAVIORAL EFFECTS: – Migration, – intraspecific attraction, – aggregation, – aggression, – predation, – vulnerability, – mating • Binding: – Reversible vs. Irreversible binding • Irreversible binding (covalent) causes harmful effects. • Types of bonding: – Covalent > ionic > Hydrogen binding > Vanderwaals > hydrophilic • Biochemical responses: – Biochemical response could be protective or nonprotective (may or may not cause harmful effect). • Non-protective biochemical responses have Carcinogenic, Mutagenic, Teratogenic and Neurotoxic potentials. • Protective biochemical responses: – Monoxygenase (OCs and PAHs) – Induction and binding to metalothionein (Cu, Cd, Zn and Hg) – Binding to blood plasma, bones and hair (Metals and xenobiotics) – Dissolving in fat (organics- e.g. OCs) – Mineralization ( e.g. MeHg to Hg 2+) – Demineralization (As to MeAs) Protective biochemical response • Heavy metals for example can be stored and detoxified by organisms either by binding to specific proteins e.g. metallothioneins (-SH proteins) • In some cases it is mineralized to inorganic form, which is less toxic: e.g. Hg bound to Se is a mineralized Hg (detoxified Hg: MeHg to Hg). On the other hand, the inorganic form, which is more toxic can be methylated to a less toxic form e.g. As. Protective biochemical response PHASE 1 REACTION. • Organic pollutants could also be metabolized and detoxified by Cytochrome P450 enzymes (Microsomal Monoxygenase; MMO). PHASE 2 REACTION • The metabolites undergo conjugation with endogenous molecules e.g. GSH. • For some chemicals the metabolites/conjugated form are more toxic than the parent compound and can lead to cancer formation. Non-protective response – Binding to DNA (DNA adduct) – DNA Structural damage (strands break) induced by genotoxic compounds – Binding to SH-Protein (Protein adduct); enzymes and proteins – Nerotoxicity: prolongation of K and Na flow and inhibition of AChE activity in the brain Non-protective response – Mitochondrial Poison (lost of proton gradient) – Inhibition of vitamin K cycle (competition with vit K binding site) – Inhibition of Thyroxine (competition with thyrosine binding site) – Inhibition of ATPase (enzymes for transport of ions e.g. K, Na, Ca) Non-protective response • Environmental Estrogens (eg DDT) and androgens (tributhyl Tin) • Endocrine disrupters (binding to endocrine receptors) • Photosystems of Plants (interruption of electron flow) • Plant growth regulation Physiological changes Non-protective biochemical responses lead to Physiological changes which could be observed at organ and organism levels • Organ level: – accumulation of Cd in kidney, which could cause cell death (cytotoxicity), resulting in dysfunction of the kidney – PAHs and Lung cancer • Organism level: – decrease in production (growth and reproduction) – changes in gene frequency – decrease in resources acquisition and uptake Behavioral Changes – Either or both physiological and biochemical effects could lead to behavioral effects at organism level– e.g. caring for young ones and avoidance of predator. Biochemical, Physiological and Behavioral effects on the individual organism culminate effects observed at the Population, Community and Ecosystem levels. Population Changes • Changes in population may come about as a result of direct changes in numbers of individual organism and gene frequency (resistance) • By indirect means (decrease in population of predators due to toxic chemicals could lead to increase in numbers of its prey). Diclofenac residues as the cause of vulture population decline in Pakistan. Nature. 2004 Feb 12;427(6975):630-3. • Diclofenac causes kidney damage, increased serum uric acid concentrations, visceral gout, and death. • Changes in community structure – change in pyhtoplankton assemblage due to eutrophication – acid rain affecting microorganisms in the soil, aquatic life • Changes in Ecosystem level (earth as an ecosystem) – carbon dioxide increase – ozone depletion Some General effects of pollution on an Ecosystem • Decrease in the suitability of the abiotic component as a habitat for the biotic components of the ecosystem, which have been naturally established and adapted to that ecosystem • Detrimental impact on part of the biotic component (vulnerable species) as related to the intensity and type of pollution • Alteration to the community structure and in most cases, there is a declined in the number of species present Some General effects of pollution on an Ecosystem • Matter and Energy flow within the ecosystem changes • Removal of larger organisms with longer life spans • The appearance of opportunistic species with short life spans exhibiting large population fluctuations in time and space What is an Endocrine Disruptor ? “An exogenous agent that interferes with the synthesis, secretion, transport, binding, action, or elimination of natural hormones in the body that are responsible for the maintenance of homeostasis, reproduction, development and/or behavior. “ Mechanisms of endocrine disrupting compounds 1) Binding and activating the estrogen receptor 2) Binding but not activating the estrogen receptor (therefore acting as an anti-estrogen) 3) Binding other receptors 4) Modifying the metabolism of natural hormones 5) Modifying the number of hormone receptors in a cell 6) Modifying the production of natural hormones Hormone regulation and feedback control Estrogen levels depend on Estrodiol serum-binding proteins -fetoprotein (AFP) Testosterone-estradiol binding globulin Xenoestrogens (ex. DES) 100-fold lower affinity than E2 to these binding protein Bioavailability increased Non-genomic mechanisms of ED action • Compounds of the azole type, such as ketoconazole and the fungicide fenarimol, inhibit these CYP isoforms and consequently can also affect steroid synthesis while the now-banned anti-fouling agent tributyltin and its metabolites, which have strong ED potential, are thought to act by the same mechanism, probably by inhibition of aromatase. Genomic mechanisms of ED action • bind to oestrogen receptors and so act as pseudoestrogens in vivo, giving feminising effects • tamoxifen and diethylstilbestrol) and industrial chemicals (e.g. octylphenol and bisphenol-A • fungicide vinclozolin binds competitively to the androgen receptor (Shono et al., 2004), blocking the cellular actions of testosterone on androgendependent tissue growth and behaviour patterns • chlordecone, inhibit binding to the oestrogen and progesterone receptors (Guzelia, 1982), whereas bisphenol-A can block ligand binding to the thyroid receptor Timing, duration, and amount of exposure. Organization vs. activation Timing, duration, and amount of exposure are each important determinants of the outcome. There are windows of vulnerability during fetal development in which small exposures to endocrine disruptors may have profound effects not observed in adults. Studies of the intrauterine position of mice during fetal development show that slight fluctuations of steroid hormone levels influence genital morphology, timing of puberty, sexual attractiveness, sexual behavior, aggressiveness, and activity level of offspring. Various Classes of EDCs Flame Retardants Fungicides Herbicides Insecticides Metals Pharmaceuticals Phenols Plasticizers Polyaromatic Hydrocarbons Soy Products Surfactants Polybrominated diphenyl ether Vinclozolin Atrazine Methoxychlor Tributyltin Ethynyl Estradiol Bisphenol A Phthalates PCBs, dioxins Genistein Alkylphenol Ethoxylates PBDEs(多溴二苯基醚) • Polybrominated diphenyl ethers (PBDEs) are a class of recalcitrant and bioaccumulative halogenated compounds that have emerged as a major environmental pollutant. PBDEs are used as a flame-retardant and are found in consumer goods such as electrical equipment, construction materials, coatings, textiles and polyurethane foam (furniture padding). Bioavailability of PBDEs Found in animals Increase in fish Increase in whales Sewage sludge PCBs Found in Lake Washington Fish (PBDEs next?) Found in human (breast milk) PBDEs Breast Milk - Sweden (Norén and Mieronyté, 1998) Health Effects of PBDEs Similar to PCBs (Polychlorinated biphenyls) PBT (Persistent Bioaccumulative Toxicant) No human data Animals studies indicate Effects thyroid hormone levels Neurobehavioral toxicity Effects development - alters Behavior Impairs memory and learning Delays sexual development Vinclozolin • Vinclozolin is a fungicide that has been shown to cause Leydig cell tumors and atrophy of the accessory sex glands in adult rodents. In addition, exposure of rats during pregnancy causes a pattern of malformations in the male urogenital tract . • Androgen receptor antagonist Atrazine • A chlorotriazine herbicide, is used to control annual grasses and broadleaf weeds. • suppression of the luteinizing hormone surge during the estrus cycle by atrazine leads to the maintenance of elevated blood levels of 17betaestradiol (E2) and prolactin. • The mechanism for tumor development may include one or more of the following: the induction of aromatase (CYP19) and/or other P450 oxygenases, an antagonist action at the estrogen feedback receptor in the hypothalamus, an agonist action at the mammary gland estrogen receptor or an effect on adrenergic neurons in the hypothalamic-pituitary pathway. 雙酚A Bisphenol-A BPA is used in the manufacture of polycarbonate plastics and epoxy resins from which food and beverage containers and dental materials are made. Perinatal exposure to environmentally relevant BPA doses results in morphological and functional alterations of the male and female genital tract and mammary glands that may predispose the tissue to earlier onset of disease, reduced fertility and mammary and prostate cancer 聚氯乙烯(PVC)製的嬰兒固齒器、玩具 讓長牙的嬰兒咬玩的固齒器、洗澡玩的軟性玩具、價格不貴的流 行卡通玩具常常是PVC製品,在使用中可能釋出鄰苯二甲酸 (phthalates)這類有致癌性的環境荷爾蒙。 【安全替代品】仔細查看成分標示,凡是嬰幼兒可能放到口中把 玩的玩具一定選購PE(聚乙烯)製品。 苯乙烯 alkylphenol(烷基酚) 攤販、自助餐店、速食店的熱飲杯(裝湯、茶、咖啡)、泡麵的 碗麵及杯麵絕大多數都使用聚苯乙烯(polystyren)的塑膠容器, 簡稱為PS,被國人稱為保麗龍。保麗龍是全球環保界的頭痛產品。 其原料單体叫苯乙烯,是已知致癌物,且製造過程所添加的塑化 劑alkylphenol(烷基酚)也是會干擾內分泌的環境荷爾蒙,二 者在使用過程很容易溶出到食物中。 化妝品中的環境荷爾蒙 多數的化妝品、卸妝用清潔用品含有幾類的環境 荷爾蒙: •壬基苯酚乙烯(一種非離子界面活性劑) •鄰苯二甲酸(phthalates) •烷基酚(alkylphenol) Tributyltin (TBT) 三丁基錫是一種有機錫化合物,常被 添加於船舶油漆中,以防止貝類及藻 類附著於船身,由於具有殺菌效果, 所以也可以作為殺菌劑使用 受到三丁基錫或三苯基錫污染的雌岩螺,因生殖孔阻塞受 精卵無法排出,堆積在生殖管道內變紅變黑形成壞死組織, 此時長出陰莖的雄化作用也同時被引發 許多生物對有機錫的代謝能力低,在低濃度長 時間的污染下,負面效果即能呈現,有機錫累 積在食物階層頂端的鯨豚肝臟也普遍存在 (up to 10 mg/kg) ,累積濃度在開發國家及近岸 種類較高,物種間因代謝能力的差異受有機錫 污染影響也不同,鑒於有機錫污染對海域生態 的威脅,全世界預計在2008年禁止三丁機錫做 為油漆添加物。 有機錫也是致畸胎劑,在北海核電廠附近 的畸形魚 核電廠為了保持進、出水口的暢通,避免 藻類或貝類攀附縮短壽命,所以在進、出 水口處塗抹劇毒「有機錫」,毒殺了近海 生態。 Phthalates鄰苯二甲酸酯 • 軟化劑,廣泛存在於化粧品、兒童玩具、 食品包裝中 。 • 聚氯乙烯PVC製品,在使用中可能釋出 鄰苯二甲酸 • male infertility • Interfere with cholesterol uptake and androgen biosynthesis Alkylphenol(烷基酚) • 保麗龍製造過程所添加的塑化劑alkylphenol (烷基酚)也是會干擾內分泌的環境荷爾蒙 • disrupted reproduction in pikeperch • In juvenile fish a decrease in the percentage of males and an increase of intersex fish was observed in relation to dose of NP and time of exposure to this alkylphenol. • Exposure of adult males to the NP led to the reduction in fecundity, milt quality and fertility. EDSTAC Tier 1 Assays Concerned with detecting • • • • • • • Receptor binding assays (ER and AhR) Uterotrophic Hershberger Pubertal female Steroidogenesis Frog metamorphosis Fish reproductive screen EDSTAC Tier 2 dose-response relationship • Mammal development and reproduction • Bird development and reproduction • Mysid shrimp life cycle • Fish reproduction and development • Amphibian development and reproduction Species-dependent sex determination Mammal XY/XX synthesis of testosterone/functional androgen receptors estrogen receptor in the brain Birds WZ/WW The ability to synthesize and recognize 17-estradiol is necessary for female CNS and gonadal sexual development to occur Reptile temperature-dependent sex determination (aromatase related) Temperature-dependent sex determination thermosensitive period (TSP) Temperature determines their sex. A nest temperature of 73.5 degrees would develop males. If it heats up to 83.5, hormones would trigger changes causing the embryonic cells to differentiate as females. III. Field studies Manipulative Observational (biomonitoring) This sections looks briefly at the field of microcosm and mesocosm toxicity testing. Microcosms - laboratory systems that are intended to physically simulate an ecosystem or a major subsystem of an ecosystem. They are an attempt to create systems that display ecosystem properties while permitting control of conditions and replication of treatments at reasonable cost. There are two types of microcosms, assembled and excised. One of the more common assembled type is the aqutic microcosm developed by Taub (see Suter, 1993). This system consists of ten species of algae, five zooplankters (cladoceran, amphipod, ostracod, protozoan, and rotifer), and a bacterium in a defined aqueous medium with serile sand sediment all contained in gallon jar under fluorescent lights. The advantage of the system is that it is standardized, similar results can be achieved from different labs, researchers can compare results with different chemicals, and the limited and constant array of species makes it more likely that the cause of observed responses can be determined making it possible to model the ecosystem level interactions for extrapolation to the field. However, they are very much oversimplified. Excised microcosms are segments of ecosystems that have been removed from the environment as a unit or a few units and placed in containers in the laboratory. They contain natural assemblages of biota, natural median and are more realistic. The are also less amenable to quality control and to comparisons. Examples include: •Mixed flask culture - mixed culture of microbes and microinvertebrates derived from one or more natural communities and held in the lab. •Pond microcosm - water, sediment, macrophytes, and associated biota obtained from a shallow pond or the littoral zone of a lake or slow-moving river •Site-specific aquatic microcosm - large tank of ambient water, a sediment core suspended in the water, and associated biota Mesocosms - outdoor experimental systems that are delimited and to some extent enclosed. These systems offer more realism than microcosms due to their larger size and more natural physical conditions but can still provide replication, control of chemical exposure, and some control of biotic components. Mesocosm studies are currently a requirement for pesticide registration in the U.S. Mesocosms are also either assembled such as artificial ponds and streams or delimited such as limnocorrals and other enclosures of portions of an ecosystem. Biomonitoring 生物監測(Biomonitoring)在歐洲國家於20世紀 初首先使用藻類腐水指標系統監測水質,其後陸續 建立底棲生物及魚類指標監測方法。一般河川水質 監測只有分析水中理化參數,而忽略水中生物之存 在與否。Loeb及Spacie(1994)指出,水中生物 因長期生活棲息之水中環境,任何外來物質刺激 (Stress),他們首當其衝,故他們才是最佳環境 監測器。他們身體健康情況或存在與否,即是反映 水質好壞。 河川生物監測 藻類評估水質使用之方法為藻屬指數 底棲水生昆蟲使用之方法為科級生物指標及快速生 物評估法 魚類評估方法有魚類生物整合性指標法及魚類指標 法 An Index of Biotic Integrity (IBI) is a tool (index) which we use to determine the health (integrity) of the fish community (biotic) in a given river. Webster's defines an index as "a ratio or other number derived from a series of observations and used as an indicator or measure". Biotic is defined as "of or relating to life". And integrity is defined as "the quality or state of completeness". The IBI examines three components of the fish community to determine its health. By knowing the abundance (total number of fish), the diversity (number of different species), and trophic (food chain) interactions, we get an idea of how healthy the fish community is in a given area. Indicator species A species whose status provides information on the overall condition of the ecosystem and of other species in that ecosystem. Particular tolerant or sensitive to environmental contamination. Ex. Ephemeroptera, Plecoptera, and Trichoptera Biomarker responses to specific chemical are well characterized Accumulated environmental contaminants 未受污染水體中生存之生物指標 石蠅 扁蜉蝣 高身鏟頷魚 長鬚石蠶 流石蠶 網蚊 台灣鏟頷魚 錐螺 澤蟹 台灣間爬岩鰍 香魚 輕度污染水體中生存之生物指標 縞石蠶 雙尾小蜉蝣 台灣石 網石蠶 石蛉 水蠆 脂鮠 台灣纓口鰍 小裳蜉蝣 台灣馬口魚 中度污染水體中生存之生物指標 水蛭 平頷 大口螺類 大眼華 短吻鐮柄魚 姬蜉蝣 粗首 褐吻 虎 極樂吻 虎 嚴重污染水體中生存之生物指標 紅蟲 顫蚓 泥鰍 大眼海鰱 水蟲 大肚魚 吳郭魚 鱧魚 Example 1 • What will happen When Raw Domestic Sewage from a Sewered Community of 40,000 people flows into a stream? Ecological Risk Assessment has three primary phases Problem formulation Analysis Risk characterization •Data required to conduct an ecological risk assessment include the following: •Toxicity to wildlife, aquatic organisms, plants, an nontarget insects •Environmental fate •Environmental transport •Estimated environmental concentrations •Where and how the pesticide will be used •What animals and plants will be exposed •Climatologic, meterologic, and soil information