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15.3: Waterbesoedeling - Biologie

15.3: Waterbesoedeling - Biologie


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Die wêreldwye waterkrisis behels ook waterbesoedeling. Wêreldwyd kan verbeterde waterveiligheid, sanitasie en higiëne tot 9% van alle siektes en 6% van alle sterftes voorkom.

Benewens die wêreldwye waterkrisis, bedreig chemiese besoedeling deur landbou, nywerheid, stede en mynbou die wêreldwye waterkwaliteit. Sommige chemiese besoedelstowwe het ernstige en bekende gesondheidseffekte, terwyl baie ander langtermyn gesondheidseffekte het wat swak bekend is. In die VSA pas tans meer as 40 000 waterliggame by die definisie van 'gestremdes' wat deur EPA gestel word, wat beteken dat hulle nie 'n gesonde ekosisteem kan ondersteun nie en ook nie aan die kwaliteit van waterstandaarde kan voldoen nie. In Gallup openbare meningspeilings wat oor die afgelope dekade gedoen is, stel Amerikaners deurgaans waterbesoedeling en watervoorsiening as die belangrikste omgewingsbekommernisse oor kwessies soos lugbesoedeling, ontbossing, spesie-uitwissing en aardverwarming.

Enige natuurlike water bevat opgeloste chemikalieë, waarvan sommige belangrike menslike voedingstowwe is, terwyl ander skadelik vir die menslike gesondheid kan wees. Die konsentrasie van 'n waterbesoedeling word algemeen in baie klein eenhede soos dele per miljoen (ppm) of selfs dele per miljard (ppb). 'N Arseenkonsentrasie van 1 ppm beteken 1 deel arseen per miljoen dele water. Dit is gelykstaande aan een druppel arseen in 50 liter water. Om jou 'n ander perspektief te gee oor die waardering van klein konsentrasie-eenhede, is die omskakeling van 1 dpm na lengte-eenhede 1 cm (0.4 duim) in 10 km (6 myl) en die omskakeling van 1 dpm na tydeenhede is 30 sekondes in 'n jaar. Totale opgeloste vaste stowwe (TDS) verteenwoordig die totale hoeveelheid opgeloste materiaal in water. Gemiddelde TDS -waardes vir reënwater, rivierwater en seewater is onderskeidelik ongeveer 4 dpm, 120 dpm en 35.000 dpm.

Waterbesoedeling Oorsig

Waterbesoedeling is die besmetting van water deur 'n oormaat hoeveelheid van 'n stof wat mense en/of die ekosisteem kan benadeel. Die vlak van waterbesoedeling hang af van die oorvloed van die besoedeling, die ekologiese impak van die besoedelende stof en die gebruik van die water. Besoedeling word verkry uit biologiese, chemiese of fisiese prosesse. Alhoewel natuurlike prosesse soos vulkaniese uitbarstings of verdamping soms waterbesoedeling kan veroorsaak, is die meeste besoedeling afkomstig van menslike, landgebaseerde aktiwiteite (Figuur ( PageIndex {2} )). Waterbesoedelende stowwe kan deur verskillende waterreservoirs beweeg, soos wat die water wat hulle dra deur stadiums van die watersiklus vorder (Figuur (PageIndex{3})). Waterverblyftyd (die gemiddelde tyd wat 'n watermolekule in 'n waterreservoir deurbring) is baie belangrik vir besoedelingsprobleme omdat dit die besoedelingspotensiaal beïnvloed. Water in riviere het 'n relatief kort verblyf tyd, so besoedeling is gewoonlik slegs kortstondig. Besoedeling in riviere kan natuurlik net na 'n ander reservoir, soos die see, beweeg, waar dit verdere probleme kan veroorsaak. Grondwater word tipies gekenmerk deur stadige vloei en langer verblyftyd, wat grondwaterbesoedeling besonder problematies kan maak. Laastens, besoedeling verblyf tyd Dit kan baie langer wees as die waterverblyfstyd, omdat 'n besoedeling vir 'n lang tyd in die ekosisteem opgeneem kan word of in sediment opgeneem kan word.

Besoedelende stowwe betree watertoevoer vanaf puntbronne, wat maklik identifiseerbaar en relatief klein plekke is, of niepuntbronne, wat groot en meer diffuse gebiede is. Puntbronne van besoedeling sluit in plase van dierefabrieke (figuur ( PageIndex {4} )) wat 'n groot aantal en hoë digtheid van vee, soos koeie, varke en hoenders, grootmaak. Pype wat ingesluit is, is ook pype van 'n fabriek of rioolsuiweringsaanleg. Gekombineerde rioolstelsels met 'n enkele stel ondergrondse pype om riool- en stormwaterafloop uit strate op te vang vir die behandeling van afvalwater, kan die belangrikste bron van besoedeling wees. Tydens swaar reën kan stormwaterafloop rioolkapasiteit oorskry, wat veroorsaak dat dit terugspring en onbehandelde riool direk in oppervlakwater mors (Figuur (PageIndex{5})).

Nie -besoedelde bronne van besoedeling sluit in landbouvelde, stede en verlate myne. Reënval loop oor die land en deur die grond en tel besoedelstowwe soos onkruiddoders, plaagdoders en kunsmis van landboulande en grasperke op; olie, antivries, dierlike afval en padsout uit stedelike gebiede; en suur en giftige elemente uit verlate myne. Hierdie besoedeling word dan na oppervlakwaterliggame en grondwater gelei. Besoedeling van nie -bronbronne, wat die grootste oorsaak van waterbesoedeling in die VSA is, is gewoonlik baie moeiliker en duurder om te beheer as besoedeling deur die bron, vanweë die lae konsentrasie, veelvuldige bronne en veel groter volume water.

Tipes waterbesoedeling

Suurstof-eisende afval is 'n uiters belangrike besoedelstof vir ekosisteme. Die meeste oppervlakwater wat in aanraking kom met die atmosfeer, bevat 'n klein hoeveelheid opgeloste suurstof, wat deur waterorganismes benodig word vir sellulêre asemhaling. Bakterieë ontbind dooie organiese materiaal en verwyder opgeloste suurstof (O2) volgens die volgende reaksie:

[ ext{organiese materiaal} + O_{2} ightarrow CO_{2} + H_{2} O]

Te veel verrottende organiese materiaal in water is 'n besoedeling omdat dit suurstof uit water verwyder, wat vis, skulpvis en waterinsekte kan doodmaak. Die hoeveelheid suurstof wat deur aërobies (in die teenwoordigheid van suurstof) word bakteriese ontbinding van organiese materiaal genoem biochemiese suurstofbehoefte (BOD). Die hoofbron van dooie organiese materiaal in baie natuurlike waters is riool; gras en blare is kleiner bronne. 'n Onbesoedelde waterliggaam met betrekking tot BOB is 'n onstuimige rivier wat deur 'n natuurlike woud vloei. Turbulensie bring water voortdurend in aanraking met die atmosfeer waar die O2 inhoud word herstel. Die inhoud van opgeloste suurstof in so 'n rivier wissel van 10 tot 14 dpm O2, BOD is laag, en skoonwatervis soos forel. 'n Besoedelde waterliggaam met betrekking tot suurstof is 'n stilstaande diep meer in 'n stedelike omgewing met 'n gekombineerde rioolstelsel. Hierdie stelsel bevoordeel 'n hoë inset van dooie organiese koolstof van riooloorloop en beperkte kans vir watersirkulasie en kontak met die atmosfeer. In so 'n meer het die opgeloste O2 inhoud is ≤5 ppm O2, BOD hoog en laag O2-verdraagsame visse, soos karp en baber, oorheers.

Oormatige plantvoedingstowwe, veral stikstof (N) en fosfor (P), is besoedeling wat nou verwant is aan afval wat suurstof benodig. Waterplante benodig ongeveer 15 voedingstowwe vir groei, waarvan die meeste volop is in water. N en P word genoem voedingstowwe beperkomdat hulle gewoonlik in lae konsentrasies in water voorkom en dus die totale hoeveelheid plantgroei beperk. Dit verklaar waarom N en P hoofbestanddele in die meeste kunsmis is. Hoë konsentrasies N en P van menslike bronne (meestal landbou- en stedelike afloop, insluitend kunsmis, riool en fosforgebaseerde skoonmaakmiddels) kan verbouing veroorsaak eutrofikasie, wat lei tot die vinnige groei van akwatiese produsente, veral alge. Dik matte van drywende alge of gewortelde plante lei tot ’n vorm van waterbesoedeling wat die ekosisteem beskadig deur viskieue te verstop en sonlig te blokkeer. ’n Klein persentasie algspesies produseer gifstowwe wat diere, insluitend mense, kan doodmaak. Eksponensiële groei van hierdie alge word genoem skadelike alg bloei. Wanneer die produktiewe algelaag sterf, word dit suurstof-veeisende afval, wat baie lae O kan skep2 konsentrasies in die water (< 2 dpm O2), 'n toestand genoem hipoksie. Dit lei tot 'n dooie sone omdat dit die dood veroorsaak as gevolg van versmoring vir organismes wat nie die omgewing kan verlaat nie. Na raming word 50% van mere in Noord-Amerika, Europa en Asië negatief deur kulturele eutrofikasie geraak. Daarbenewens het die grootte en aantal mariene hipoksiese sones dramaties gegroei oor die afgelope 50 jaar, insluitend 'n baie groot dooie sone geleë langs Louisiana in die Golf van Mexiko. Kulturele eutrofikasie en hipoksie is moeilik om te bestry, omdat dit hoofsaaklik veroorsaak word deur besoedeling wat nie in die bron gereguleer kan word nie, en N en P, wat moeilik uit die afvalwater verwyder kan word.

Patogene Dit is siektes wat mikroörganismes veroorsaak, byvoorbeeld virusse, bakterieë, parasitiese wurms en protosoë, wat 'n verskeidenheid dermsiektes veroorsaak, soos disenterie, tifus en cholera. Patogene is die belangrikste oorsaak van die waterbesoedelingskrisis wat aan die begin van hierdie afdeling bespreek is. Ongelukkig word byna 'n miljard mense regoor die wêreld daagliks aan watergedraagde patogeenbesoedeling blootgestel en ongeveer 1,5 miljoen kinders, hoofsaaklik in onderontwikkelde lande, sterf elke jaar aan watergedraagde siektes van patogene. Patogene betree water hoofsaaklik van menslike en dierlike fekale afval as gevolg van onvoldoende rioolbehandeling. In baie onderontwikkelde lande word riool in plaaslike waters gestort óf onbehandeld óf na slegs rudimentêre behandeling. In ontwikkelde lande kan onbehandelde rioolafvoer voorkom as gevolg van oorstromings van gekombineerde rioolstelsels, swak bestuurde veefabrieksplase en lekkende of stukkende rioolverwyderingstelsels. Water met patogene kan geremedieer word deur chloor of osoon by te voeg, deur te kook, of deur die riool in die eerste plek te behandel.

Oliestortings is 'n ander soort organiese besoedeling. Oliestortings kan die gevolg wees van supertenkskip-ongelukke soos die Exxon Valdez in 1989, wat 10 miljoen liter olie in die ryk ekosisteem van kus Alaska gestort het en massiewe getalle diere doodgemaak het. Die grootste mariene oliestorting was die Deepwater Horizon-ramp, wat begin het met 'n aardgasontploffing (Figuur (PageIndex{6})) by 'n olieput 65 km van die kus van Louisiana af en vir 3 maande in 2010 gevloei het, wat 'n geskatte vrystelling van 200 miljoen liter olie. Die ergste oliestorting wat ooit plaasgevind het tydens die Persiese Golfoorlog van 1991, toe Irak doelbewus ongeveer 200 miljoen liter olie in Koeweit aan die kus gegooi het en meer as 700 oliebrande aan die brand gesteek het wat enorme wolke rook en suurreën vir meer as nege maande vrygestel het.

Tydens 'n oliestorting op water dryf olie na die oppervlak omdat dit minder dig is as water, en die ligste koolwaterstowwe verdamp, wat die grootte van die storting verminder, maar die lug besoedel. Dan begin bakterieë die oorblywende olie ontbind, in 'n proses wat baie jare kan neem. Na 'n paar maande kan slegs ongeveer 15% van die oorspronklike volume oorbly, maar dit is in dik asfaltklonte, 'n vorm wat veral skadelik is vir voëls, visse en skulpvisse. Opruimingsoperasies kan skuimskepe insluit wat olie van die wateroppervlak af suig (slegs effektief vir klein stortings), beheerde verbranding (werk net in vroeë stadiums voordat die ligte, ontvlambare deel verdamp maar ook die lug besoedel), dispergeermiddels (skoonmaakmiddels wat olie opbreek om die ontbinding daarvan te versnel, maar sommige dispergeermiddels kan giftig wees vir die ekosisteem), en bioremediasie (voeg mikroörganismes by wat spesialiseer in olie wat vinnig ontbind, maar dit kan die natuurlike ekosisteem ontwrig).

Giftige chemikalieë behels baie verskillende soorte en bronne, hoofsaaklik van nywerheid en mynbou. Algemene soorte giftige chemikalieë sluit in gevaarlike chemikalieë en aanhoudende organiese besoedelstowwe wat DDT (plaagdoder), dioksien (onkruiddoder-byproduk) en PCB's (polichloorbifeniele, wat as 'n vloeibare isolator in elektriese transformators gebruik is) insluit. Aanhoudende organiese besoedelstowwe (POP's) het 'n lang lewe in die omgewing, biomagneer deur die voedselketting en kan giftig wees. Nog 'n kategorie van giftige chemikalieë sluit in radioaktiewe materiale soos sesium, jodium, uraan en radongas, wat kan lei tot langtermyn blootstelling aan radioaktiwiteit as dit in die liggaam kom. 'n Laaste groep giftige chemikalieë is swaar metale soos lood, kwik, arseen, kadmium en chroom, wat deur die voedselketting kan ophoop. Swaar metale word algemeen vervaardig deur die nywerheid en by metaalmyne. Arseen en kwik word hieronder in meer besonderhede bespreek.

Arseen (As) is al vir baie eeue bekend as 'n agent van die dood. Wetenskaplikes het eers onlangs besef dat gesondheidsprobleme veroorsaak kan word deur oor 'n lang tyd klein arseenkonsentrasies in water te drink. Dit betree die watertoevoer natuurlik van verwering van arseenryke minerale en van menslike aktiwiteite soos steenkoolverbranding en smelt van metaalerts. Die ergste geval van arseenvergiftiging het voorgekom in die digbevolkte verarmde land Bangladesj, wat jaarliks ​​100 000 sterftes as gevolg van diarree en cholera ervaar het weens die drink van oppervlakwater wat met patogene besmet is as gevolg van onbehoorlike rioolbehandeling. In die 1970's het die Verenigde Nasies hulp verleen aan miljoene vlakwaterputte, wat gelei het tot 'n dramatiese afname in patogeniese siektes. Ongelukkig produseer baie van die putte water wat natuurlik ryk is aan arseen. Dit is tragies dat na raming 77 miljoen mense (ongeveer die helfte van die bevolking) per ongeluk blootgestel is aan giftige arseenvlakke in Bangladesj. Die Wêreldgesondheidsorganisasie noem dit die grootste massavergiftiging van 'n bevolking in die geskiedenis.

Kwik (Hg) word gebruik in 'n verskeidenheid elektriese produkte, soos droëselbatterye, fluoresserende gloeilampe en skakelaars, sowel as in die vervaardiging van verf, papier, vinielchloried en swamdoders. Kwik werk op die sentrale senuweestelsel en kan verlies van sig, gevoel en gehoor sowel as senuweeagtigheid, bewerigheid en dood veroorsaak. Soos arseen, kom kwik natuurlik in die watertoevoer deur verwering van kwikryke minerale en deur menslike aktiwiteite soos steenkoolverbranding en metaalverwerking. ’n Bekende kwikvergiftigingsgeval in Minamata, Japan, het metielkwikryke industriële ontlading behels wat hoë Hg-vlakke in vis veroorsaak het. Mense in die plaaslike vissersdorpe het meer as 30 jaar lank tot drie keer per dag vis geëet, wat tot meer as 2 000 sterftes gelei het. Gedurende daardie tyd het die verantwoordelike maatskappy en nasionale regering min gedoen om die probleem te versag, te help verlig of selfs te erken.

Harde water bevat oorvloedige kalsium en magnesium, wat die vermoë om seepsoppe te ontwikkel verminder, en die vorming van kalsium (kalsium en magnesiumkarbonaat) op warmwatertoestelle verbeter. Waterversagmiddels verwyder kalsium en magnesium, wat die water in staat stel om maklik te skuim en skaalvorming te weerstaan. Harde water ontwikkel natuurlik uit die ontbinding van kalsium- en magnesiumkarbonaatminerale in die grond; dit het geen negatiewe gevolge vir die gesondheid by mense nie.

Grondwater besoedeling kan voorkom vanaf ondergrondse bronne en al die besoedelingsbronne wat oppervlakwater besoedel. Algemene bronne van grondwaterbesoedeling is ondergrondse opgaartenks vir brandstof, septiese tenks, landbouaktiwiteite, stortingsterreine en ontginning van fossielbrandstowwe. Algemene grondwaterbesoedeling sluit nitraat, plaagdoders, vlugtige organiese verbindings en petroleumprodukte in. Nog 'n lastige kenmerk van grondwaterbesoedeling is dat klein hoeveelhede van sekere besoedelingstowwe, bv. petroleumprodukte en organiese oplosmiddels, groot gebiede kan besoedel. In Denver, Colorado, het 80 liter van verskeie organiese oplosmiddels 4,5 biljoen liter grondwater besmet en 'n 5 km lange besmettingspluim opgelewer. 'N Groot bedreiging vir die kwaliteit van die grondwater is van ondergrondse brandstoftanks. Brandstoftenks word gewoonlik ondergronds by vulstasies gestoor om ontploffingsgevare te verminder. Voor 1988 in die VSA kon hierdie opgaartenks van metaal gemaak word, wat kan korrodeer, lek en vinnig plaaslike grondwater besoedel. Nou word lekdetektors vereis en die metaalopgaartenks is veronderstel om teen korrosie beskerm te word of met veselglastenks vervang te word. Tans is daar ongeveer 600 000 ondergrondse brandstoftenktenks in die VSA en meer as 30% voldoen steeds nie aan die EPA -regulasies ten opsigte van die voorkoming van vrystellings of lekopsporing nie.


15.3 Die omgewing

Op die eerste oogopslag lyk dit asof die omgewing nie 'n sosiologiese onderwerp is nie. Die natuurlike en fisiese omgewing is iets wat geoloë, weerkundiges, oseanograwe en ander wetenskaplikes moet bestudeer, nie sosioloë nie. Tog het ons net bespreek hoe die omgewing beïnvloed word deur bevolkingsgroei, en dit klink beslis na 'n sosiologiese bespreking. Die omgewing is eintlik om baie redes 'n sosiologiese onderwerp.

Eerstens is ons ergste omgewingsprobleme die gevolg van menslike aktiwiteite, en hierdie aktiwiteit is, soos baie menslike gedrag, die regte onderwerp vir sosiologiese studie. Hierdie handboek het baie gedrag bespreek: rassistiese gedrag, seksistiese gedrag, kriminele gedrag, seksuele gedrag en ander. Net soos hierdie gedrag sosiologiese studie werd is, so is die gedrag wat die omgewing benadeel (of probeer verbeter).

Tweedens het omgewingsprobleme 'n beduidende impak op mense, net soos die vele ander sosiale probleme wat sosioloë bestudeer. Ons sien die duidelikste bewyse van hierdie impak wanneer 'n groot orkaan, 'n aardbewing of 'n ander natuurramp toeslaan. In Januarie 2010 het 'n verwoestende aardbewing byvoorbeeld Haïti getref en meer as 250 000 mense, of ongeveer 2,5 persent van die bevolking van die land, dood. Die gevolge van hierdie natuurrampe op die ekonomie en die samelewing van Haïti sal beslis ook vir baie jare gevoel word.

Soos blyk uit hierdie foto wat geneem is in die nadraai van die aardbewing in 2010 wat Haïti verwoes het, kan veranderinge in die natuurlike omgewing tot groot veranderinge in 'n samelewing lei. Omgewingsveranderinge is een van die vele bronne van sosiale verandering.

Verenigde Nasies se Ontwikkelingsprogram – Aardbewing in Haïti – CC BY-NC-ND 2.0.

Stadiger veranderinge in die omgewing kan ook 'n groot sosiale impak hê. Soos vroeër opgemerk, het industrialisering en bevolkingsgroei die besoedeling van ons lug, water en grond verhoog. Klimaatsverandering, 'n groter omgewingsprobleem, het ook relatief stadig gekom, maar bedreig die hele planeet op 'n manier wat navorsers oor klimaatsverandering gedokumenteer het en ongetwyfeld vir die res van ons lewens en daarna sal ondersoek. Ons keer binnekort terug na hierdie twee omgewingsprobleme.

'N Derde rede waarom die omgewing 'n sosiologiese onderwerp is, is 'n bietjie meer kompleks: oplossings vir ons omgewingsprobleme vereis veranderinge in die ekonomiese en omgewingsbeleid, en die moontlike implementering en impak van hierdie veranderinge hang grootliks af van sosiale en politieke faktore. In die Verenigde State, byvoorbeeld, baklei die twee groot politieke partye, korporatiewe lobbyiste en omgewingsorganisasies gereeld oor pogings om omgewingsregulasies te versterk.

'N Vierde rede is dat baie omgewingsprobleme sosiale ongelykheid weerspieël en illustreer op grond van sosiale klas en ras en etnisiteit: Soos met baie probleme in ons samelewing, gaan die armes en mense van kleur dikwels erger as dit kom by die omgewing. Ons keer later terug na hierdie tema in ons bespreking van omgewingsrassisme.

Vyfdens, pogings om die omgewing te verbeter, dikwels genoem die omgewingsbewegingvorm 'n sosiale beweging en is as sodanig weer sosiologiese studie waardig. Sosioloë en ander sosiale wetenskaplikes het baie studies gedoen oor waarom mense by die omgewingsbeweging aansluit en oor die impak van hierdie beweging.


Professionals en studente wat die omgewing bestudeer, veral wat besoedeling betref, ook staatswerkers en natuurbewaarders/ekoloë

Deel 1 Prosesse wat die lot en vervoer van kontaminante beïnvloed

Hoofstuk 1 Die omvang van globale besoedeling

1.2 Globale perspektief van die omgewing

1.3 Besoedeling en Bevolkingsdruk

1.4 Oorsig van omgewingskarakterisering

1.5 Vooruitgang in analitiese opsporingstegnologie

1.6 Die risikogebaseerde benadering tot besoedelingswetenskap

1.7 Afvalbestuur, terreinherstel en ekosisteemherstel

Verwysings en addisionele leesstof

Hoofstuk 2 Fisies-chemiese eienskappe van gronde en die ondergrond

2.1 Grond- en ondergrondse omgewings

2.5 Basiese Fisiese Eienskappe

Verwysings en addisionele leesstof

Hoofstuk 3 Fisies-chemiese kenmerke van waters

3.2 Unieke eienskappe van water

3.5 Oksidasie-verminderingsreaksies

3.6 Lig in wateromgewings

3.8 Mere en reservoirs — Die lentestelsel

3.9 Strome en riviere — Die lotiese stelsel

3.10 Grondwater — Water in die ondergrond

Verwysings en bykomende leeswerk

Hoofstuk 4 Fisies-chemiese eienskappe van die atmosfeer

4.2 Fisiese eienskappe en struktuur

Verwysings en bykomende leeswerk

Hoofstuk 5 Biotiese kenmerke van die omgewing

5.1 Groot groepe organismes

5.2 Mikroörganismes in oppervlakgronde

5.3 Mikro-organismes in die ondergrond

5.4 Biologiese Opwekking van Energie

5.5 Grond as 'n omgewing vir mikrobes

5.6 Aktiwiteit en Fisiologiese toestand van mikrobes in grond

5.7 Opsomming van grondbakterieë via verdunning en plating

5.9 Mikro-organismes in Oppervlakwater

Verwysings en addisionele leesstof

Hoofstuk 6 Fisiese prosesse wat kontaminantvervoer en lot beïnvloed

6.1 Vervoer van kontaminante en lot in die omgewing

6.2 Besoedelingseienskappe

6.6 Transformasie-reaksies

6.7 Karakterisering van ruimtelike en tydelike verspreidings van kontaminante

6.8 Skatting van faseverdelings van kontaminante

6.9 Kwantifisering van besoedeling en noodlot

Verwysings en addisionele leesstof

Hoofstuk 7 Chemiese prosesse wat vervoer en noodlot van kontaminante beïnvloed

7.2 Basiese eienskappe van anorganiese kontaminante

7.3 Basiese eienskappe van organiese kontaminante

7.5 Abiotiese transformasie reaksies

Verwysings en addisionele leesstof

Hoofstuk 8 Biologiese prosesse wat vervoer en noodlot van kontaminante beïnvloed

8.1 Biologiese effekte op besoedelingstowwe

8.2 Die algehele proses van biodegradasie

8.3 Mikrobiese aktiwiteit en biodegradasie

8.4 Biodegradasie-paaie

8.5 Transformasie van metaalbesoedelingstowwe

Verwysings en bykomende leeswerk

Deel 2 Monitering, assessering en regulering van omgewingsbesoedeling

Hoofstuk 9 Fisiese kontaminante

9.3 Deeltjies in lug of aërosols

Verwysings en bykomende leeswerk

Hoofstuk 10 Chemiese kontaminante

10.2 Tipes kontaminante

10.3 Bronne: Landbou-aktiwiteite

10.4 Bronne: Nywerheids- en vervaardigingsaktiwiteite

10.5 Bronne: Munisipale afval

10.6 Bronne: Diensverwante aktiwiteite

10.7 Bronne: Hulpbronontginning/produksie

10.8 Bronne: Radioaktiewe kontaminante

10.9 Natuurlike bronne van kontaminante

Verwysings en bykomende leeswerk

Hoofstuk 11 Mikrobiese kontaminante

11.1 Waterverwante mikrobiese siekte

11.2 Klasse van siektes en tipes patogene

11.3 Tipes patogene organismes

11.4 Bronne van patogene in die omgewing

11.5 Lot en vervoer van patogene in die omgewing

11.6 Standaarde en kriteria vir aanwysers

Verwysings en bykomende leeswerk

Die rol van omgewingsmonitering in besoedelingswetenskap

12.2 Steekproefneming en monitering Basiese beginsels

12.3 Statistiek en geostatistiek

12.4 Monsternemings- en moniteringsinstrumente

12.5 Grond en Vadose Sone Monsterneming en Monitering

12.6 Monitering en monitering van grondwater

12.7 Oppervlaktewatermonster en monitering

12.8 Atmosfeermonsterneming en -monitering

Verwysings en addisionele leesstof

Hoofstuk 13 Omgewingstoksikologie

13.1 Geskiedenis van moderne toksisiteit in die Verenigde State

13.2 Giftig Versus Nie-giftig

13.4 Evaluering van toksisiteit

13.5 Reaksies op toksiese stowwe

13.9 Chemiese toksisiteit: Algemene oorwegings

13.10 Chemiese toksisiteit: geselekteerde stowwe

Verwysings en bykomende leeswerk

Hoofstuk 14 Risiko-evaluering

14.1 Die konsep van risiko-evaluering

14.2 Die proses van risiko -assessering

14.3 Ekologiese risikobepaling

14.4 Mikrobiese risikobepaling

Verwysings en bykomende leeswerk

Hoofstuk 15 Omgewingswette en -regulasies

15.2 Die Wet op Veilige Drinkwater

15.4 Wet op Omvattende Omgewingsreaksie, Vergoeding en Aanspreeklikheid

15.5 Federal Insecticide and Rodenticide Act

15.7 Wet op Hulpbronbewaring en -herwinning (RCRA)

15.8 Die Wet op die Voorkoming van Besoedeling

15.9 Ander regulerende agentskappe en ooreenkomste

Verwysings en addisionele leesstof

Deel 3 Versagting van grond- en waterbesoedeling

Hoofstuk 16 Grond en besoedeling van grond

16.6 Landbouaktiwiteite

16.8 Industriële afval met hoë soute en organiese bestanddele

Verwysings en addisionele leesstof

Hoofstuk 17 Ondergrondse besoedeling

17.1 Grondwater as 'n hulpbron

17.2 Grondwaterbesoedeling

17.3 Risikobeoordeling van grondwaterbesoedeling

17.4 Puntbron kontaminasie

17.4.1 Gevaarlike organiese chemikalieë

17.5 Diffuse-bron kontaminasie

17.6 Ander probleme met grondbesmetting

17.7 Volhoubaarheid van grondwaterbronne

Verwysings en addisionele leesstof

Hoofstuk 18 Oppervlaktewaterbesoedeling

18.1 Oppervlakte varswaterhulpbronne

18.2 Mariene waterbronne

18.3 Bronne van oppervlaktewaterbesoedeling

18.4 Sedimente as oppervlakwaterbesoedeling

18.6 Voedingstowwe en Eutrofikasie van Oppervlaktewaters

18.7 Organiese verbindings in water

18.8 Enteriese patogene as oppervlaktewaterbesoedeling

18.9 Totale maksimum daaglikse vragte (TMDL's)

18.10 Kwantifisering van oppervlaktewaterbesoedeling

18.12 Verdunning van afvalwater

18.13 Kleurstofopsporing van pluime

18.14 Ruimtelike en temporele variasie van pluimkonsentrasies

18.15 Monitering van nakoming

Verwysings en addisionele leesstof

Hoofstuk 19 Grond- en grondwateropwinning

19.3 Terreinkarakterisering

19.4 Saneringstegnologieë

Verwysings en bykomende leeswerk

Hoofstuk 20 Herstel van ekosisteem en grondaanwinning

20.2 Karakterisering van die werf

20.5 Benaderings tot ekosisteem-herstel

Verwysings en bykomende leeswerk

Deel 4 Atmosferiese besoedeling

Hoofstuk 21 Sensoriese besoedeling, elektromagnetiese velde en radiofrekwensie -straling

21.5 Reuk as sensoriese besoedeling

21.6 Elektromagnetiese velde en radiofrekwensiestraling

Verwysings en addisionele leesstof

Hoofstuk 22 Binnelugkwaliteit

22.1 Grondbeginsels van binnenshuise luggehalte

22.2 Bronne van binnenshuise lugbesoedeling

22.3 Faktore wat blootstelling aan binnenshuise lugbesoedeling beïnvloed

Verwysings en bykomende leeswerk

Hoofstuk 23 Atmosferiese besoedeling

23.1 Begrippe oor lugbesoedeling

23.2 Bronne, tipes en gevolge van lugbesoedeling

23.3 Weer en besoedeling

23.4 Besoedelingstendense in die Verenigde State

Verwysings en addisionele leesstof

24.2 Aardverwarming en die kweekhuiseffek

24.4 Oplossings vir die probleme van wêreldwye omgewingsverandering

Verwysings en addisionele leesstof

Deel 5 Afval- en waterbehandeling en -bestuur

Hoofstuk 25 Industriële en munisipale behandeling en wegdoening van vaste afval

25.2 Relevante regulasies vir industriële en munisipale vaste afval

25.3 Belangrike vorme van nywerheidsafval

25.4 Behandeling en wegdoening van industriële afval

25.5 Hergebruik van nywerheidsafval

25.6 Behandeling en wegdoening van munisipale vaste afval

Verwysings en bykomende leeswerk

Hoofstuk 26 Munisipale Afvalwaterbehandeling

26.1 Die aard van afvalwater (riool)

26.2 Moderne afvalwaterbehandeling

26.5 Grondtoediening van afvalwater

26.6 Vleilande en Akwakultuurstelsels

Verwysings en addisionele leesstof

Hoofstuk 27 Grondtoediening van biovaste stowwe en diereafval

27.1 Biosoliede en dierlike afval: 'n historiese perspektief en huidige vooruitsig

27.2 Die aard van afvalwater (riool)

27.3 Afvalwater (riool) behandeling

27.4 Metodes van grondtoediening van biovaste stowwe

27.5 Voordele van grondtoediening van biovaste stowwe

27.6 Gevare vir grondtoepassing van Biosolides

27.7 Bronne van diere-afval

27.8 Niepunt Versus Punt Bron Besoedeling

27.9 Voordele van grondtoediening van diereafval

27.10 Gevare vir grondtoediening van diereafval

27.11 Openbare persepsies van grondaansoek

Verwysings en addisionele leesstof

Hoofstuk 28 Drinkwaterbehandeling en watersekuriteit

28.1 Waterbehandelingsprosesse

28.3 Faktore wat ontsmettingsmiddels beïnvloed

28.5 Desinfeksie-byprodukte

28.6 Residensiële waterbehandeling

28.8 Monitering van gemeenskapswatergehalte

Verwysings en bykomende leeswerk

Deel 6 Opkomende kwessies in besoedelingswetenskap

Hoofstuk 29 Geneties gemanipuleerde gewasse en mikrobes

29.1 Inleiding tot nukleïensure

29.2 Rekombinante DNA Tegnologie

29.3 Oordrag van nukleïensuurreekse van een organisme na 'n ander (kloning)

29.4 Chemiese sintese, volgordebepaling en amplifikasie van DNA

29.5 Heteroloë geenuitdrukking in pro- en eukariote

29.6 Geneties gemanipuleerde plante vir landbou

29.7 Geneties gemanipuleerde plante vir herstel

29.8 Mikrobiese bystand

29.9 Potensiële probleme as gevolg van geneties gemodifiseerde organismes

Verwysings en addisionele leesstof

Hoofstuk 30 Antibiotika-weerstandige bakterieë en geenoordrag

30.1 Waarom is antibiotika 'n probleem?

30.2 Klassifikasie en funksie van antibiotika

30.3 Ontwikkeling van bakteriële antibiotiese weerstand

30.4 Oordrag van genetiese materiaal deur horisontale genoordrag

30.5 Algemene omgewings wat HGT bevoordeel

30.6 Isolasie en opsporing van antibiotika-weerstandige bakterieë

30.7 Voorkoms van antibiotika-weerstandige bakterieë in verskillende omgewings

30.8 Geenoordrag tussen bakterieë—Hoe belangrik is dit?

30.9 Opsomming en gevolgtrekkings

Verwysings en addisionele leesstof

Hoofstuk 31 Farmaseutiese middels en endokriene ontwrigters

31.1 Endokriene ontwrigters en hormone

31.2 Belangrikheid van EDC's in water

31.3 Voorkoms van EDC's in water

31.4 Lot en vervoer van estrogeniese verbindings in munisipale afvalwater

31.5 Metodes om estrogeenaktiwiteit in water te meet

31.6 Wat is die risiko van EDC's?

Verwysings en bykomende leeswerk

Hoofstuk 32 Epiloog: is die toekoms van besoedelingsgeskiedenis?

32.1 Die rol van die regering in die beheer van besoedeling

32.2 Navorsingsprioriteite wat nodig is om menslike gesondheid te beskerm

32.3 Voorkoming van besoedeling van aarde, lug en water

32.4 Is die toekoms van besoedelingsgeskiedenis?


2. Metodologie en data

Ons begin hierdie afdeling met 'n gedetailleerde bespreking van ons twee beleide van belang. Na 'n reeks omgewingsrampe in die 1950's en 1960's, was Japan aan die voorpunt van omgewingsregulering. In die 1970's is ses nuwe omgewingswette uitgevaardig en 'n verdere agt is verskerp. Die 1990's het 'n verdere verskerping van omgewingswetgewing gesien, en in 1993 het Japan geïmplementeer wat bekend gestaan ​​het as die Basiese Omgewingswet. In 1997 was Japan die gasheer van die VN se raamkonvensie oor klimaatsverandering, wat tot die Kyoto -protokol gelei het en internasionale omgewingskwessies op die voorgrond geplaas het in Japan se nywerheidsbeleid. In 2001 is 'n Ministerie van die Omgewing gestig, wat die vorige rolle van die Omgewingsagentskap insluit, wat omgewingsbeleid in die hart van regeringsbesluitneming neem. The culmination of these various policies is that Japan established one of the strongest frameworks for achieving a clean and healthy environment earlier than most OECD countries and demonstrated that a good environmental reputation is not only good for the environment but is also a valuable economic and cultural asset (Sumikura 1998). 8

Although the current environmental literature tends to concentrate on cap and trade, taxes, and command and control policies, a little-known method used in Japan in the early 1970s was the environmental interest rate differential. The aim of the environmental interest rate subsidy program was to encourage firms to invest in abatement technologies to reduce emissions. Abatement investment includes technology to reduce air pollution (such as desulphurization), water pollution, noise pollution, recycling, and industrial waste. A gap caused by arbitrarily setting lower interest rates for certain financial schemes than the current market rates can be considered as a subsidy for abatement investment. There were three main finance schemes for large firms in abatement investment. One scheme used finance programs by the Japan Development Bank (JDB), which is a government bank under the Ministry of Finance. The JDB had special lending programs in abatement investment, which offered lower interest rates than market rates. This program continued until 1999. The other scheme was conducted by the Japan Environmental Corporation (JEC) (Kougai Boushi Jiigyoudan) (1965–2003). JEC's lending programs for environmental projects ended in 1999. In contrast to the JDB scheme, the JEC money was targeted at not only large firms but also small- and medium-sized enterprises (SMEs). An example of this is the Japan Corporation for Small and Medium Enterprise (JASME) (Chusho Kigyo Kinyu Koko) (1953–2008), which was a government bank that specialized in helping SMEs. All three lending programs used the same strategy of lowering interest rates for investment in abatement technologies, although the level of discount against market rates differed by lending body (discussed further subsequently).

The policy initiative to use interest rates in this way required the Japanese government to establish a rate of interest on borrowing between the market rate and the zaito rate (the rate used for government public finance policy). Any funds borrowed at this cheap rate of interest were used to finance environmental projects with the aim of alleviating abatement costs and reducing pollution. The money could be borrowed by large firms from the JDB, the JEC, or local government bodies. Funding from the JDB ceased in 1999. Funding from the JEC also finished in 1999 (lending actually stopped in 1998). In part the policy was no longer possible because of Japan's zero interest rates from 1998 onward.

The subsidized environmental loan program started in 1960 when the JDB starting making loans for investment that would mitigate water pollution. In 1963 this was extended to loans to help reduce pollution of soot and smoke. Two years later the JEC also started a loan program for anti-pollution measures followed by the JDB in 1971. In that same year the Agency of Industrial Science and Technology set up a subsidy system. The main developments in what we could call environmental finance were as follows: In 1960 JDB started loans for investment against water pollution and then in 1963 it started a loan program for investment against soot and smoke. In 1965 JEC started its loan program for anti-pollution investment. In 1971 the JDB also implemented an anti-pollution investment loan program. This was matched in 1971 by the Agency of Industrial Science and Technology, which also set up a subsidy system for anti-pollution investment. Finally, in 1974 the Agency of Industrial Science and Technology directly subsidized environmental technology for NOx reductions.

We now turn to our PCA measure. Japan is a highly centralized country, the central government sets environmental standards and tends to have uniform regulations across the country. Environmental damages, however, are idiosyncratic across regions and some cities and villages need more stringent regulations. This led to a number of regional governments coming to voluntary agreements with local polluting firms, although the voluntary nature of any agreement means that they could not be legally enforced. The agreements tended to specify more stringent environmental regulations than the national laws and regulations and thus no legal penalty could be enforced as long as the national regulation levels were met. Thus, cities and environmental community groups were required to supervise the firm's behavior. One of the most famous examples is Yokohama city, which signed an agreement with Tokyo Denryoku (TEPCO) in 1965 and with Electric Power Development Co. Ltd. (Dengen Kaihatsu) in 1964. 9 Because firms want to give the impression of being “greener” and environmentally friendly, PCAs were popular with firms willing to accept these agreements in the 1970s and 1980s when public disquiet about the high levels of pollution were at their greatest and as a result so was the threat of even stricter government regulation.

In our data set the PCA variable is measured as the number of ratified pollution control municipal agreements signed during a given year (flow data) between a firm/plant and a local government body. We count the number of agreements in the manufacturing sector, the agricultural sector, and an overall total (including the energy sector). Figure 1 shows the number of agreements in the manufacturing sector. The contents of each agreement depend on the negotiating stance of each municipality and are taken from the Environmental White Paper by the Ministry of Environment Japan for each year from 1972 onwards and the Pollution White Paper for years before 1971. As Figure 1 clearly shows, the number of signed PCAs peaked around 1990 just before the 1993 Basic Law was enacted, and then fell away dramatically.


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Inhoud

Fragmentation of river ecosystems Edit

A dam acts as a barrier between the upstream and downstream movement of migratory river animals, such as salmon and trout. [3]

Some communities have also begun the practice of transporting migratory fish upstream to spawn via a barge. [3]

Reservoir sedimentation Edit

Rivers carry sediment down their riverbeds, allowing for the formation of depositional features such as river deltas, alluvial fans, braided rivers, oxbow lakes, levees and coastal shores. The construction of a dam blocks the flow of sediment downstream, leading to downstream erosion of these sedimentary depositional environments, and increased sediment build-up in the reservoir. While the rate of sedimentation varies for each dam and each river, eventually all reservoirs develop a reduced water-storage capacity due to the exchange of "live storage" space for sediment. [4] Diminished storage capacity results in decreased ability to produce hydroelectric power, reduced availability of water for irrigation, and if left unaddressed, may ultimately result in the expiration of the dam and river. [5]

The trapping of sediment in reservoirs reduce sediment delivery downstream, which negatively impacts channel morphology, aquatic habitats and land elevation maintenance of deltas. [6] Apart from dam removal, there are other strategies to mitigate reservoir sedimentation.

Flushing flow method Edit

The flushing flow method involves partially or completely emptying the reservoir behind a dam to erode the sediment stored on the bottom and transport it downstream. [7] [6] Flushing flows aim to restore natural water and sediment fluxes in the river downstream of the dam, however the flushing flow method is less costly compared to removing dams or constructing bypass tunnels.

Flushing flows have been implemented in the Ebro river twice a year in autumn and spring since 2003, except for two dry years in 2004 and 2005. [8] [9] The construction of multiple dams on the Ebro river disrupted the delivery of sediments downstream and as a result, the Ebro delta faces a sediment deficit. The river channel also narrowed and bank erosion increased. [7] During experiments, it was found that suspended sediment concentration during flushing flows is double that of natural floods, although the total water discharge is lower. This means that flushing flows have a relatively high sediment transport capacity, [8] which in turn suggests that flushing flows positively impact downstream river ecosystems, maximising sediment delivery to the lowest reaches of the river. [10] A total of 340,000 t/year of sediment could be delivered to the Ebro delta, which could result in a net accretion rate of 1 mm per year. [7]

Sediment bypasses Edit

Sediment bypass tunnels can partially restore sediment dynamics in rivers downstream of dams, and are primarily used in Japan and Switzerland. [11] Bypass tunnels divert part of the incoming water and sediments during floods into a tunnel around a reservoir and dam. The water and sediment thus never enter the reservoir but join the river again below the dam. [12] Bypass tunnels reduce riverbed erosion and increase morphological variability below the dam. [13]

River line and coastal erosion Edit

As all dams result in reduced sediment load downstream, a dammed river is greatly demanding for sediment as it will not have enough sediment. This is because the rate of deposition of sediment is greatly reduced since there is less to deposit but the rate of erosion remains nearly constant, the water flow erodes the river shores and riverbed, threatening shoreline ecosystems, deepening the riverbed, and narrowing the river over time. This leads to a compromised water table, reduced water levels, homogenization of the river flow and thus reduced ecosystem variability, reduced support for wildlife, and reduced amount of sediment reaching coastal plains and deltas. [5] This prompts coastal erosion, as beaches are unable to replenish what waves erode without the sediment deposition of supporting river systems. [14] Downstream channel erosion of dammed rivers is related to the morphology of the riverbed, which is different from directly studying the amounts of sedimentation because it is subject to specific long term conditions for each river system. For example, the eroded channel could create a lower water table level in the affected area, impacting bottomland crops such as alfalfa or corn, and resulting in a smaller supply. [15] In the case of the Three Gorges Dam in China the changes described above now appears to have arrived at a new balance of erosion and sedimentation over a 10-year period in the lower reaches of the river. The impacts on the tidal region have also been linked to the upstream effects of the dam. [16]

Nutrients sequestration Edit

Once a dam is put in place represents an obstacle to the flux of nutrients such as carbon (C), nitrogen (N), phosphorus (P), and silicon (Si) on downstream river, floodplains and delta. The increased residence time of these elements in the lentic system of a reservoir, compared to the lotic system of a river, promotes their sedimentation or elimination [17] which can be up to 40%, 50%, and 60% for nitrogen, phosphorus and silica respectively [18] and this ultimately changes nutrients stoichiometry in the aquatic ecosystem downstream a dam. The stochiometric imbalance of nitrogen, phosphorus, and silicon of the outflow can have repercussion on downstream ecosystems by shifting the phytoplankton community at the base of the food web with consequences to the whole aquatic population. [19] [20] [21] An example is the effect of the construction of the Aswan High dam in Egypt, where the drop in nutrient concentration to the Nile delta impeded the diatom blooms causing a substantial decrease the fish population of Sardinella aurita en Sardinella eba, while the reduced load of mud and silt affected the micro-benthic fauna leading to the decline of shrimp population. [22] The change in nutrients stoichiometry and silicon depletion at a river delta can also cause harmful algal and bacterial blooms to the detriment of diatoms' growth for whom silicon availability represents a milestone for shells' formation.

Since dammed rivers store nutrients during their lifespan, it can be expected that when a dam is removed, these legacy nutrients are remobilized causing downstream ecosystems' eutrophication and probable loss of biodiversity, thereby achieving the opposite effect desired by the river restoration action at dam dismissal.

Water temperature Edit

The water of a deep reservoir in temperate climates typically stratifies with a large volume of cold, oxygen poor water in the hypolimnion. Analysis of temperature profiles from 11 large dams in the Murray Darling Basin (Australia) indicated differences between surface water and bottom water temperatures up to 16.7 degrees Celsius. [23] If this water is released to maintain river flow, it can cause adverse impacts on the downstream ecosystem including fish populations. [24] Under worse case conditions (such as when the reservoir is full or near full), the stored water is strongly stratified and large volumes of water are being released to the downstream river channel via bottom level outlets, depressed temperatures can be detected 250 - 350 kilometres downstream. [23] The operators of Burrendong Dam on the Macquarie River (eastern Australia) are attempting to address thermal suppression by hanging a geotextile curtain around the existing outlet tower to force the selective release of surface water. [25]

Natural ecosystems destroyed by agriculture Edit

Many dams are built for irrigation and although there is an existing dry ecosystem downstream, it is deliberately destroyed in favor of irrigated farming. After the Aswan Dam was constructed in Egypt it protected Egypt from the droughts in 1972–73 and 1983–87 that devastated East and West Africa. The dam allowed Egypt to reclaim about 840,000 hectares in the Nile Delta and along the Nile Valley, increasing the country's irrigated area by a third. The increase was brought about both by irrigating what used to be desert and by bringing under cultivation 385,000 hectares that were natural flood retention basins. About half a million families were settled on these new lands.

Effects on flood-dependent ecology and agriculture Edit

In many [ kwantifiseer ] low lying developing countries [ example needed ] the savanna and forest ecology adjacent to floodplains and river deltas are irrigated by wet season annual floods. Farmers annually plant flood recession crops, where the land is cultivated after floods recede to take advantage of the moist soil. Dams generally discourage this cultivation and prevent annual flooding, creating a dryer downstream ecology while providing a constant water supply for irrigation.

  • The Lake Manatali reservoir formed by the Manantali dam in Mali, West Africa intersects the migration routes of nomadic pastoralists and withholds water from the downstream savanna. The absence of the seasonal flood cycle causes depletion of grazing land, and is also drying the forests on the floodplain downstream of the dam. [27]
  • After the construction of the Kainji Dam in Nigeria, 50 to 70 percent of the downstream area of flood-recession cropping stopped. [28]

Potential for disaster Edit

Dams occasionally break causing catastrophic damage to communities downstream. Dams break due to engineering errors, attack or natural disaster. The greatest dam break disaster to date happened in China in 1975 killing 200,000 Chinese citizens. Other major failures during the 20th century were at Morbi, India (5,000 fatalities), at Vajont, Italy (2000 dead), while three other dam failures have each caused at least 1000 fatalities.

Flood control Edit

The controversial Three Gorges Dam in China is able to store 22 cubic kilometres of floodwaters on the Yangtze River. The 1954 Yangtze River floods killed 33,000 people and displaced 18 million people from their homes. In 1998 a flood killed 4000 people and 180 million people were affected. The flooding of the reservoir caused over a million people to relocate, then a flood in August 2009 was completely captured by the new reservoir, protecting hundreds of millions of people downstream.

Mercury cycling and methylmercury production Edit

The creation of reservoirs can alter the natural biogeochemical cycle of mercury. Studies conducted on the formation of an experimental reservoir by the flooding of a boreal wetland showed a 39-fold increase in the production of toxic methylmercury (MeHg) following the flooding. [29] The increase in MeHg production only lasted about 2–3 years before returning to near normal levels. However, MeHg concentration in lower food chain organisms remained high and showed no signs of returning to pre-flood levels. The fate of MeHg during this time period is important when considering its potential to bioaccumulate in predatory fish. [30]

Effects on humans Edit

Siektes
Whilst reservoirs are helpful to humans, they can also be harmful as well. One negative effect is that the reservoirs can become breeding grounds for disease vectors. This holds true especially in tropical areas where mosquitoes (which are vectors for malaria) and snails (which are vectors for Schistosomiasis) can take advantage of this slow flowing water. [31]

Resettlement
Dams and the creation of reservoirs also require relocation of potentially large human populations if they are constructed close to residential areas. The record for the largest population relocated belongs to the Three Gorges dam built in China. Its reservoir submerged a large area of land, forcing over a million people to relocate. "Dam related relocation affects society in three ways: an economic disaster, human trauma, and social catastrophe", states Dr. Michael Cernea of the World Bank and Dr. Thayer Scudder, a professor at the California Institute of Technology. [2] As well, as resettlement of communities, care must also be taken not to irreparably damage sites of historical or cultural value. The Aswan Dam forced the movement of the Temple at Aswan to prevent its destruction by the flooding of the reservoir.

Greenhouse gases Edit

Reservoirs may contribute to changes in the Earth's climate. Warm climate reservoirs generate methane, a greenhouse gas when the reservoirs are stratified, in which the bottom layers are anoxic (i.e. they lack oxygen), leading to degradation of biomass through anaerobic processes. [32] [ bladsy benodig ] At a dam in Brazil, where the flooded basin is wide and the biomass volume is high the methane produced results in a pollution potential 3.5 times more than an oil-fired power plant would be. [33] A theoretical study has indicated that globally hydroelectric reservoirs may emit 104 million metric tonnes of methane gas annually. [34] Methane gas is a significant contributor to global climate change. This isn't an isolated case, and it appears that especially hydroelectric dams constructed in lowland rainforest areas (where inundation of a part of the forest is necessary) produce large amounts of methane. Bruce Forsberg and Alexandre Kemenes have demonstrated that the Balbina Dam for instance emits 39000 tonnes of methane each year [35] and three other dams in the Amazon produce at least 3 to 4× as much CO
2 as an equivalent coal-fired power plant. Reasons for this being that lowland rainforests are extremely productive and thus stores far more carbon than other forests. Also, microbes that digest rotting material grow better in hot climates, thus producing more greenhouse gases. Despite of this, as of 2020, another 150 hydroelectric dams are planned to be constructed in the Amazon basin. [36] There is some indication that greenhouse gas emissions decline over the lifetime of the dam. "But even including methane emissions, total GHG [Green-House Gas] per KWh generated from hydropower is still at least half that from the least polluting thermal alternatives.Thus, from the perspective of global warming mitigation, dams are the most attractive alternative to fossil fuel based energy sources." [32]

Research conducted at the Experimental Lakes Area indicates that creating reservoirs through the flooding of boreal wetlands, which are sinks for CO
2 , converts the wetlands into sources of atmospheric carbon. [29] In these ecosystems, variation in organic carbon content has been found to have little effect on the rates of greenhouse gas emission. This means that other factors such as the lability of carbon compounds and temperature of the flooded soil are important to consider. [37]

The following table indicates reservoir emissions in milligrams per square meter per day for different bodies of water. [38]


Prodded by petition, EPA reconsiders ocean pH limits

Katherine Boyle, E&E reporter

Published: Wednesday, April 15, 2009

U.S. EPA is weighing a revision of standards aimed at preventing the acidification of marine waters.

The effort marks the first time EPA has invoked the Clean Water Act to address ocean acidification, and comes in response to a 2007 petition from the Center for Biological Diversity. The center noted that EPA has failed to update the pH standard since 1976 and has ignored research published since then.

Concerns about ocean acidification have risen lately, as research shows a link between it and rising atmospheric carbon dioxide levels. Studies show that oceans absorb about 22 million tons of CO2 per day from the atmosphere, resulting in increasing acidity that impairs marine animals' ability to build and maintain protective shells and skeletons and threatens coral reefs.

The agency moved toward stiffening marine pH standards in a Federal Register kennisgewing seeking information on possible changes in ocean acidity.

Miyoko Sakashita, an attorney with the Center for Biological Diversity's ocean program, described the notice as a step in the right direction.

"The federal government has finally acknowledged that ocean acidification is a threat," she said in a statement. "Now it must take the next step and fully implement the Clean Water Act to protect our nation's waters from 'the other CO2 problem.'"

The center says EPA's recommended pH criterion is an important benchmark for states and tribes. A stricter recommendation could potentially help promote the imposition of federal CO2 controls.

The center also asked EPA to publish a guidance providing recommendations to states on preventing ocean acidification.

"We must take immediate action to address ocean acidification, or the impacts will be catastrophic," Sakashita said. "Fortunately, we need not wait for new legislation addressing CO2 emissions, as the Clean Water Act already provides us with important tools to confront this problem."

Stakeholders will have 60 days to submit ocean acidification data to the agency. EPA plans to decide whether the pH standards should be revised within one year.


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Most of DEQ’s functions are set by Title 27A of the Oklahoma Statutes. Licensing requirements for water and wastewater system operators, as well as individual septic system installers, are found in Title 59. Administrative procedures for enforcement and rulemaking are found in Title 75. The text of all Oklahoma statutes can be found on the Oklahoma State Courts Network website.

Before being adopted, DEQ rules undergo an extensive public review process as set by statute and the Office of Administrative Rules within the Oklahoma Secretary of State’s office. Proposed rules are published twice per month in the Oklahoma Register. This office also maintains the official version of all final rules, known as the Oklahoma Administrative Code (OAC). Both the Oklahoma Register and the OAC are available online.

As a convenience, DEQ makes its rules and fee schedules available online however, please be aware that the rules and fee schedules downloaded from here are unofficial. While every effort is made to ensure accuracy, there may be mistakes. If there are any discrepancies between the rules and fee schedules downloaded from here and those outlined by statute or in the official OAC at the Office of Administrative Rules, the statutes or official rules will prevail.

A summary of rule changes passed by the Environmental Quality Board during state fiscal year 2020 can be found here.


Stencil a Storm Drain

Get outside, volunteer, and do your part to and help raise awareness about storm water pollution and water quality in Seattle neighborhoods. This spring and summer, individuals, families, and small groups practicing COVID19 safe distance practices are welcome sign up and get a free reusables kit to paint stencils next to storm drains in their neighborhood with the message:

Dump No Waste
Drains to Puget Sound/Ocean

How does a stencil help? Most storm drains direct water and pollutants to a nearby stream, lake, or the Puget Sound. A stenciled drain reminds the community that what goes into the drain will end up in local waterways directly effecting wildlife and people. When people make the storm drain connection, they are less likely to dump pollutants like soaps, paints, antifreeze, and used motor oil into storm drains.