Dr Hema Ba­boolal

The land­fills are filled with POPs, or per­sis­tent or­gan­ic chem­i­cals, as what don’t we throw away here in T&T? Those old plas­tic bot­tles of dish­wash­ing liq­uid, cook­ing oil, car pol­ish, half emp­ty bot­tled drinks, emp­ty paint and pes­ti­cide con­tain­ers, they of­ten get dumped with the rest of the house­hold garbage. Petro­chem­i­cals are found in these and thou­sands of man­u­fac­tured prod­ucts that are com­posed of or con­tain in­put chem­i­cals de­rived from crude oil or nat­ur­al gas.

Pes­ti­cides, her­bi­cides, ro­den­ti­cides (for con­trol­ling rats), and fungi­cides, these too fall in­to the cat­e­go­ry of POPs and are al­most all man-made. What these sub­stances have in com­mon is that they share a car­bon-hy­dro­gen ‘back­bone’, mak­ing them ‘or­gan­ic’ sub­stances. Lip­sticks, body lo­tion, de­ter­gents, fab­ric (poly­ester, ny­lons), and clean­ing prod­ucts are all com­mon house­hold items which have a promi­nent or­gan­ic base com­po­nent.

The ‘per­sis­tent’ part comes about when the mol­e­c­u­lar struc­tures are so sta­ble and new to the bac­te­ria and fun­gi (the plan­et’s waste pro­cess­ing or­gan­isms) that there are few or no nat­u­ral­ly oc­cur­ring mech­a­nisms that al­low their break­down, mak­ing them xeno­bi­otics.

Some of these ‘new’ man-made chem­i­cals can al­so cause harm to us hu­mans and to oth­er or­gan­isms that are ex­posed. Sev­er­al POPs can build up in­side the body (bio-ac­cu­mu­late) and cause can­cer, neur­al dis­eases, re­pro­duc­tive is­sues and put strain on our liv­ers, kid­neys and im­mune sys­tems.

Plas­tics are made from a string of re­peat­ing or­gan­ic mol­e­cules eg styrene or vinyl chlo­ride, which are linked on a mol­e­c­u­lar lev­el (re­sult­ing in poly­styrene, polyvinyl chlo­ride-PVC, for ex­am­ple), with ad­di­tives that give the struc­ture, colour and form suit­ed to their pur­pose. Though de­signed to be durable, plas­tics are still sub­ject to phys­i­cal break­down process­es (eg ero­sion via the move­ment of waves in the sea, or wind ac­tion) mak­ing the bits of plas­tic that hang around ever small­er. This dura­bil­i­ty can lead to the build-up of mi­croplas­tics every­where. Ev­i­dence is mount­ing that mi­croplas­tics are harm­ful to hu­man health.

Pes­ti­cides, her­bi­cides

Mech­a­ni­sa­tion has al­lowed farm­ing prac­tices to be­come ef­fi­cient, high-yield­ing and ca­pa­ble of sup­port­ing—at least in the­o­ry—our large glob­al hu­man pop­u­la­tion. Large sin­gle-crop farms (eg wheat, rice and sug­ar­cane) have cre­at­ed oth­er prob­lems such as the need for vast amounts of pest con­trol mech­a­nisms. Even with the best in­ten­tions, there have been un­want­ed con­se­quences. Back in the 1940s, a gen­er­a­tion of pes­ti­cides—organochlo­rines—was de­vel­oped which proved quite ef­fec­tive in ad­dress­ing the grow­ing pest prob­lem. They were used in large quan­ti­ties dur­ing the Viet­nam war and were still in com­mon use in mos­qui­to coils lo­cal­ly. Com­pounds such as diphenyl-dichloro-trichloroethane (DDT) (metabolised as dichloro-diphenyl-dichloroeth­yl­ene or DDE) bioac­cu­mu­lat­ed in liv­ing things. The prob­lem was that they didn’t break down eas­i­ly. To­day, de­riv­a­tives of DDT/DDE can be found in al­most every liv­ing per­son across the globe.

The next gen­er­a­tion of pes­ti­cides, organophos­phates, had a much short­er lifes­pan, but is tox­ic to aquat­ic life, and large­ly re­placed organochlo­rines. The third gen­er­a­tion of in­sec­ti­cides, syn­thet­ic pyrethroids, is based on a nat­u­ral­ly oc­cur­ring pes­ti­cide ex­tract­ed from the chrysan­the­mum plant, but these chem­i­cals are al­so tox­ic to aquat­ic or­gan­isms.

Peo­ple us­ing these chem­i­cals and prod­ucts need to use them ap­pro­pri­ate­ly and dis­pose of them care­ful­ly.

The point we are at

Plan­et Earth bal­ances many in­ter­con­nect­ed life sup­port­ing sys­tems. Any dis­rup­tion to these sys­tems caus­es a cas­cade of con­se­quences which in turn, re­quires na­ture to re-bal­ance. In a cer­tain re­gard, this is what is hap­pen­ing with cli­mate change. In­creased con­cen­tra­tion of or­gan­ic and oth­er chem­i­cals in the air that hap­pen to pre­vent the loss of heat has caused the plan­et to grad­u­al­ly warm.

Volatile or­gan­ic pol­lu­tants that don’t read­i­ly break down are a large part of this group of chem­i­cals—Green­house Gas­es (GHGs). The sci­ence in­di­cates that glob­al warm­ing will mean more en­er­gy for storms and greater ex­tremes in weath­er pat­terns. In ad­di­tion, more dis­eases will ap­pear due to the bioac­cu­mu­la­tion of or­gan­ic sub­stances in liv­ing or­gan­isms.

What we can do

Take cloth or reusable bags to the gro­cery/mar­kets. Re­quest that take­out be sup­plied in biodegrad­able con­tain­ers.

Re­cy­cling—re­pur­pose or re­cy­cle any­thing we can. Old food and veg­etable peel­ings can be turned in­to com­post to sup­port a gar­den or fruit trees.

Use nat­ur­al pest con­trol op­tions where pos­si­ble eg Neem oil, soapy wa­ter for mealy bugs, bay leaves for rice and beans to ward off wee­vils.

Use pes­ti­cides and oth­er chem­i­cals spar­ing­ly and leave enough time for any residue to wash off be­fore har­vest­ing.

Nev­er burn chem­i­cals, emp­ty con­tain­ers or prod­ucts, as these may re­lease tox­ic fumes. Rinse, fill with news­pa­per and dis­pose. The on­ly ap­proved land­fill for tox­ic waste dis­pos­al in Trinidad is at For­res Park.

Have some lo­cal flow­er­ing plants in the yard that can pro­vide nec­tar for the bees, as they are es­sen­tial pol­li­na­tors.

Buy pro­duce that is lo­cal and in sea­son as much as pos­si­ble. This could save mon­ey and save the en­vi­ron­ment.

Nev­er lit­ter.