Water pol­lu­tion: A silent threat in south­ern Al­berta

Prairie Post (East Edition) - - Prairies - COUR­TESY SOUTH EAST AL­BERTA WA­TER­SHED AL­LIANCE

For the past four years, the World Wildlife Fund (WWF) has worked with com­mu­nity or­ga­ni­za­tions, water agen­cies, First Na­tions, re­searchers, govern­ments and in­dus­try to gather data on the health of Cana­dian wa­ter­sheds.

Re­searchers looked at the lev­els of cer­tain pol­lu­tants in rivers — such as chlo­ride, phos­pho­rus or heavy met­als — and com­pared them to the guide­lines or stan­dards set by provin­cial and fed­eral govern­ments. They also looked at long-term trends in the lev­els of th­ese sub­stances. The as­sess­ment of the South Saskatchew­an River wa­ter­shed had some dis­turb­ing news – pol­lu­tion lev­els are “very high”.

The re­port cited ev­i­dence of ev­ery type of pol­lu­tion in our wa­ter­shed, with agri­cul­tural runoff and pol­lu­tion from mu­nic­i­pal and in­dus­trial sites cre­at­ing the great­est con­cern. Pipeline leaks are also a con­cern in three of the four sub-wa­ter­sheds.

Un­der the Cana­dian En­vi­ron­men­tal Pro­tec­tion Act 1999, a sub­stance is con­sid­ered toxic if it “is en­ter­ing or may en­ter the en­vi­ron­ment in a quan­tity or con­cen­tra­tion or un­der con­di­tions that (a) have or may have an im­me­di­ate or long-term harm­ful ef­fect on the en­vi­ron­ment or its bi­o­log­i­cal di­ver­sity; (b) con­sti­tute or may con­sti­tute a dan­ger to the en­vi­ron­ment on which life de­pends; or (c) con­sti­tute or may con­sti­tute a dan­ger in Canada to hu­man life or health.” (CEPA 1999)

Toxic sub­stances can have dif­fer­ent ef­fects on hu­man health and the en­vi­ron­ment. A sub­stance that might be dan­ger­ous to wildlife in low lev­els might have no ef­fect on peo­ple even at much higher lev­els. The op­po­site is also true: some sub­stances can do more harm to hu­mans than to the en­vi­ron­ment.

Un­der CEPA, Health Canada and En­vi­ron­ment and Cli­mate Change be­gan to cat­e­go­rize the ap­prox­i­mately 23000 sub­stances on Canada’s “Do­mes­tic Sub­stances List” to make sure that any sub­stance that could po­ten­tially af­fect hu­man health (Health Canada) or the en­vi­ron­ment (En­vi­ron­ment Canada) was eval­u­ated.

The in­tent was to iden­tify sub­stances sus­pected of be­ing ei­ther per­sis­tent (chem­i­cal sub­stances that take a very long time to break down in the en­vi­ron­ment), bio-ac­cu­mu­la­tive (chem­i­cal sub­stances that can be stored in the or­gans, fat cells or blood of liv­ing or­gan­isms and re­main for a long time), or in­her­ently toxic to the en­vi­ron­ment (chem­i­cal sub­stances that are known or sus­pected, through lab­o­ra­tory and other stud­ies, to have a harm­ful ef­fect on wildlife and the nat­u­ral en­vi­ron­ment on which it de­pends).

Many of the listed sub­stances pro­vide sub­stan­tial ben­e­fits to so­ci­ety. They are used to man­u­fac­ture prod­ucts that in­crease pro­duc­tiv­ity, save lives, and make mod­ern life con­ve­nient e.g., cars, tex­tiles, pa­per, med­i­cal sup­plies, and food pack­ag­ing. Nev­er­the­less, there are le­git­i­mate and grow­ing con­cerns over the en­vi­ron­men­tal and hu­man health ef­fects of long-term chronic ex­po­sures to con­tam­i­nants found in our air, soils, water, con­sumer prod­ucts, and bod­ies.

Ac­cord­ing to Al­berta Agri­cul­ture, her­bi­cides, in­sec­ti­cides and other chem­i­cal pol­lu­tants which en­ter lakes and rivers de­grade through chem­i­cal pro­cesses such as pho­todegra­da­tion and bi­o­log­i­cal degra­da­tion by mi­crobes. Some toxic sub­stances, how­ever, can also be ab­sorbed and re­tained by aquatic or­gan­isms (bioac­cu­mu­la­tion) ei­ther di­rectly from the water or con­sumed with food.

Con­tam­i­nants that are not de­graded can be passed on in the food web with each preda­tor ac­cu­mu­lat­ing the pol­lu­tant of the or­gan­isms it had eaten (bio­mag­ni­fi­ca­tion). Bio­mag­ni­fied tox­ins or pol­lu­tants can re­sult in ma­jor prob­lems fur­ther up the food web. For ex­am­ple, dou­ble-crested cor­morants in the Great Lakes basin have had bill de­for­mi­ties from the bioac­cu­mu­la­tion of the in­sec­ti­cide DDT (En­vi­ron­ment Canada 1995). Fur­ther, the mor­tal­ity of wa­ter­fowl and other wild birds has in­creased be­cause of de­creased egg shell strength and the con­sump­tion of sport fish has been lim­ited or banned in cer­tain ar­eas due to the bioac­cu­mu­la­tion of pol­lu­tants.

Mer­cury is of par­tic­u­lar con­cern be­cause of its tox­i­c­ity to aquatic or­gan­isms and its ad­verse ef­fects on hu­man health. De­posits oc­cur nat­u­rally in all types of rocks, and hu­man sources of mer­cury to the aquatic en­vi­ron­ment in­clude in­dus­trial and mu­nic­i­pal dis­charges, at­mo­spheric de­po­si­tion or in­dus­trial emis­sions and leach­ing from land­fill sites. In May of this year, CTV re­ported that res­i­dents of the Grassy Nar­rows re­serve in On­tario have suf­fered from mer­cury poi­son­ing ever since a pa­per mill in Dry­den dumped 9,000 kilo­grams of the toxic heavy metal into the English-Wabi­goon River sys­tem in the 1960s.

A re­port au­thored by five ex­perts and re­leased last year sug­gested mer­cury could still be leak­ing into the river sys­tem. De­spite some cleanup ef­forts, mer­cury con­cen­tra­tions in the area haven’t de­creased in 30 years. Dan­ger­ous lev­els are still present in sed­i­ment and fish, caus­ing on­go­ing health and eco­nomic im­pacts in Grassy Nar­rows and the Wabaseemoo­ng First Na­tion.

In the en­vi­ron­ment, par­tic­u­larly lakes, wa­ter­ways and wet­lands, mer­cury can be con­verted to a highly toxic, or­ganic com­pound called methylmer­cury through bio­geo­chem­i­cal in­ter­ac­tions.

Methylmer­cury, which is ab­sorbed into the body about six times more eas­ily than in­or­ganic mer­cury, can mi­grate through cells which nor­mally form a bar­rier to tox­ins. It can cross the blood-brain and pla­cen­tal bar­ri­ers, al­low­ing it to re­act di­rectly with brain and fe­tal cells.

Ac­cord­ing to the Govern­ment of Canada’s web­page de­scrib­ing mer­cury in the food chain, al­most all mer­cury com­pounds are toxic and can be dan­ger­ous at very low lev­els in both aquatic and ter­res­trial ecosys­tems. Be­cause mer­cury is a per­sis­tent sub­stance, it can bioac­cu­mu­late in liv­ing or­gan­isms, in­flict­ing in­creas­ing lev­els of harm on higher or­der species such as preda­tory fish and fish-eat­ing birds and mam­mals through bio­mag­ni­fi­ca­tion. Al­though the long-term ef­fects of mer­cury on whole ecosys­tems are un­clear, the sur­vival of some af­fected pop­u­la­tions and over­all bio­di­ver­sity are at risk.

In 2009, the Al­berta govern­ment pub­lished a re­port en­ti­tled “Hu­man Health Risk As­sess­ment: Mer­cury in Fish, Rivers and Lakes, South­ern Al­berta“. The re­port dis­cusses a fish sam­pling sur­vey con­ducted in 2006 in some rivers and lakes of south­ern Al­berta.

The main ob­jec­tives of this pro­gram were to a) re­peat the sur­vey of mer­cury residues in fish in the South Saskatchew­an basin that was done in 1982 – 83; b) eval­u­ate whether fish con­sump­tion ad­vi­sories are still needed and as­sess po­ten­tial hu­man health risk; c) de­ter­mine if any of a sub­set of emerg­ing con­tam­i­nants may also be a con­cern; and d) de­ter­mine the state of aquatic ecosys­tem health in South­ern Al­berta, as de­scribed in the Water for Life Strat­egy. This re­port was fol­lowed up by one pub­lished in 2016, “Mer­cury in Fish: In Al­berta Water Bod­ies 2009–2013”.

The Govern­ment of Al­berta has been is­su­ing and re­view­ing fish con­sump­tion ad­vi­sories for fish caught from lo­cal wa­ter­bod­ies in Al­berta since the 1990s.

Fish con­sump­tion ad­vi­sories ap­ply to lo­cal sub­sis­tence con­sumers, recre­ational an­glers and res­i­dents who eat fish caught from th­ese wa­ter­bod­ies. The ad­vi­sories in­form the pub­lic about any po­ten­tial health haz­ards they may encounter when eat­ing spe­cific types of fish.

Visit the MyWildAl­berta web­site for a list of wa­ter­bod­ies with Fish Con­sump­tion Ad­vi­sories re­lated to mer­cury as well as for dioxin and fu­ran, two toxic sub­stances re­leased into the en­vi­ron­ment through burn­ing or­gan­ics and waste-water dis­charges from in­dus­trial sites.

If you would like to learn more about sur­face water qual­ity in Al­berta, Al­berta En­vi­ron­ment and Parks has an ex­cel­lent web page that de­fines sur­face water qual­ity, pro­vides an historical per­spec­tive on provin­cial mon­i­tor­ing and is­sues, and out­lines on­go­ing ac­tiv­i­ties. If you are at all in­ter­ested in water qual­ity, it is well worth your time.

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