Ecotoxicology of agrochemicals. U n i v e r s i t y o f G i r o n a

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1 Ecotoxicology of agrochemicals U n i v e r s i t y o f G i r o n a

2 Program 1. Introduction 2. Agrochemicals typology and activity 3. Environmental behavior of agrochemicals 4. Bioavailability and biotransformation 5. Environmental risk assessment and legislation Toxicity tests and toxicity thresholds 6. Multi-scale evaluation of agrochemicals ecotoxicology Biomarkers 7. Active vs passive biomonitoring example

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4 Dynamics in exposure concentrations Brock Integrated Environmental Assessment and Management Volume 9, Number 3 pp. e64 e74 Figure 3. Dynamics in exposure concentrations in (overlying) water, interstitial water and total sediment (upper 5 cm) after a single application of the fungicide carbendazim (nominal 330 mg/l) to an experimental ditch (A). Stratification of the insecticide chlorpyrifos in different sediment layers 7 days after a single application of the insecticide (nominal 44 mg/l) to an experimental ditch (Steven Crum, Wageningen UR, the Netherlands, personal communication) (B).

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7 Bioaccumulation: chemical increases in an aquatic organism exceeding that in its environment as a result of chemical uptake through all possible routes of exposure: water, food, etc.. Bioaccumulation plays a key role in determining toxicity or response in an organism due to the quantity which reaches the target organ or tissue. Used as the exposure facet in the dose-response relationship External dose Pharmaco - kinetics Biological effective dose Response

8 Aquatic organisms may accumulate chemicals directly from water: bioconcentration BCF = [Chemical organism ] / [Chemical water ]dissolved When the chemical concentration in an organism achieves a level that exceeds that in the organism s diet due to dietary accumulation, biomagnification occurs. BMF = [Chemical organism ] / [Chemical food ] Borgå et al. 2004

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10 Biomagnification Biomagnification may occur when a higher level predator eats a lower level organism and ingests the substance with it. Even though the level at the lower levels of the food chain (often referred as trophic levels) may have very low concentrations, as you move up the food chain the concentrations become higher and higher.

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12 Organic pesticides (e.g., DDTs, chlordanes) were extensively used before the 1970s due to their unique chemical properties: low water solubility low volatility low biological transformation in the environment. As a result of these properties, many of these compounds still persist in the environment 25 years later despite bans on their production and use (referred to as legacy contaminants) It is estimated that close to 70% of the global production for some compounds can still be found in the environment, posing a threat to fish and wildlife in many areas Bioaccumulate in aquatic organisms (due to their high octanol-water partition coefficient values) and many have been shown to biomagnify in aquatic food webs Chronic exposure to these persistent pollutants in aquatic species continues to remain a concern

13 Jamieson et al. Bioaccumulation of persistent organic pollutants in the deepest ocean fauna Abstract The legacy and reach of anthropogenic influence is most clearly evidenced by its impact on the most remote and inaccessible habitats on Earth. Here we identify extraordinary levels of persistent organic pollutants in the endemic amphipod fauna from two of the deepest ocean trenches (>10,000 metres). Contaminant levels were considerably higher than documented for nearby regions of heavy industrialization, indicating bioaccumulation of anthropogenic contamination and inferring that these pollutants are pervasive across the world s oceans and to full ocean depth.

14 Biotransformation/ detoxification Konwick, 2005

15 Biotransformation/ detoxification Biotransformation is a key component of elimination pathways for contaminants by making them more water soluble or more easily to excrete through the addition of key functional groups Elimination (e.g., following biotransformation) can ultimately influence the potential for a chemical to bioaccumulate and cause adverse effects in organisms, especially for current-use pesticides Aquatic organisms such as fish and invertebrates are recognized to have a limited ability to biotransform contaminants compared to birds and mammals due to their lower levels of cytochrome (CYP) P-450 1A and 2B isozymes

16 Unit 4: Exercises Mercury Inorganic or Organic Substance? 1) Explain the different processes shown in the figure Why is mercury biomagnified in the aquatic food web? Source: 2) One of the most infamous case of Hg poisoning was the Minamata Incident in Japan Explain the transformations that mercury (27 tons of mercury compounds dumped into the local bay between 1932 and 1968) had and why was it so toxic (over 2000 victims have been identified).

17 To learn more Borgå K, Fisk AT, Hoekstra PF, Muir DCG Biological and chemical factors of importance in the bioaccumulation and trophic transfer of persistent organochlorine contaminants in arctic marine food webs. Environ Toxicol Chem 23: Brock Integrated Environmental Assessment and Management Volume 9, Number 3 pp. e64 e74 Gendron AD, D J Marcogliese, S. Barbeau et al Exposure of leopard frogs to a pesticide mixture affects life history characteristics of the lungworm Rhabdias ranae. Oecologia 135: Jamieson AJ, T Marko, SB. Piertney et al Bioaccumulation of persistent organic pollutants in the deepest ocean fauna. Nature Ecology & Evolution 1, Article number: Katagi T. Bioconcentration, bioaccumulation, and metabolism of pesticides in aquatic organisms. Review. Rev Environ Contam Toxicol 2010, 204:1-132 Konwick BJ Bioaccumulation, biotransformation, and toxicity of fipronil: enantiomer-specific considerations. Master of Science Athens, Georgia. 94 pp Miller GT, S Spoolman. Living in the Environment 18th Edition. ISBN-13: Toxicants State, WetlandInfo, Department of Environment and Heritage Protection, Queensland, viewed 27 February 2017, < Aquatic sediments State, WetlandInfo, Department of Environment and Heritage Protection, Queensland, viewed 27 February 2017, <

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