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m the mine ke fro smo uld rain on Lihir? Co e acid caus /P 5IJTCPPLMFUXJMM FYQMBJOXIZ
K_\i\Xjfe]fik_`jYffbc\k K_\i\`jefXZ`[iX`efeC`_`i% `jk_Xkk_\i\_XjY\\ejfd\ K_`jYffbc\k\ogcX`ejk_\jZ`\eZ\ d`jle[\ijkXe[`e^XYflkk_\ Xe[Z_\d`jkipY\_`e[XZ`[iX`e% \o`jk\eZ\f]XZ`[iX`efeC`_`i% I\X[fekfÔe[flkn_pk_\i\`jef XZ`[iX`efeC`_`i55 page
Normal rain cycle and acid rain
To understand why there is no acid rain on Lihir we will look at:
1 How normal rain is formed 2 2 How humidity effects rain formation 3 3 What causes acid rain? 4 4 How much smoke pollution makes acid rain? 5 5 Comparing pollution on Lihir with Sydney and China 6 6 Where acid rain does occur 8–9 7 Could acid rain fall on Lihir? 10–11 8 The effect of acid rain on the environment 12
9 Time to check what you’ve learnt 13 Glossary back page
Read the smaller text in the blue bar at the bottom of each page if you want to understand the detailed scientific explanations. > > gX^\) ( ?fnefidXciX`e`j]fid\[
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K_\jZ`\eZ\Y\_`e[iX`e K_\_\Xk]ifdk_\jleZXlj\jnXk\i`ek_\ K_ifl^_\mXgfiXk`feXe[kiXejg`iXk`fe# j\X#cXb\jXe[i`m\ijkf\mXgfiXk\% The high humidity and steep mountains on Lihir cause clouds to build up quickly and produce heavy rain. Lihir is a hot tropical Humidity is a measure of the how much water vapour is island and present in the air as a gas. has a high humidity. When warm humid air (with a lot of water vapour in it) cools, it condenses to form clouds. During condensation the water in the air changes from invisible gas to liquid in the form of many tiny droplets. Because these droplets are so small they do not fall down, but instead form clouds floating around in the air, just like dust or the soot particles of smoke (Learn about smoke in Leaflet 2). As warm wind blows over the sea it picks up moisture and becomes humid. When it reaches an island with mountains, the humid air flows up the side of the mountain to the top, where it cools, and the water condenses to form clouds. That is why you often see clouds forming above islands. Eventually the tiny droplets of water in clouds start to collide and join together, growing in size. Once they reach a certain size, they can no longer float around in the air, and they start to fall, as rain. Temperature and humidity There is a relationship between the from the sea, and the warm air can contain a temperature of the air, and the greatest high concentration of gaseous water. possible concentration of water that can be Deserts and cold places have low humidity present in the air as a gas or vapour. This is because cold air cannot hold much water also known as humidity. vapour. You rarely ever see clouds in the Warm air around tropical islands has high desert because there is very little water to humidity because the high temperatures of evaporate and form clouds. the tropics cause more water to evaporate page 3 What causes acid rain? Acid rain occurs in industrial areas when the atmosphere is very polluted with smoke from very large numbers of factories and cars. The chemicals present in smoke pollution dissolve in the water in clouds to produce rainwater that is acidic. Smoke pollution Acid rain can only happen in very polluted places where there is causes so much smoke you cannot see a clear sky. acid rain. SO SO 2 2 NO NO x x water vapour SO SO 2 2 from the sea NOx SO acid rain 2 SO2 sulphur dioxide SO2 SO 2 from industry SO 2 SO2 SO2 The acid rain cycle NO nitrogen oxide from x motor vehicles NOx NOx NOx The chemistry of acid rain The pH scale is a measure of acidity. Acid rain forms when high concentrations of For more on pH see Leaflet 3 sulphur dioxide (SO2) and nitrogen oxides Pure (unpolluted) rainwater has a pH of (NOX)* dissolve in raindrops to form sulfuric around 5.6. This is in fact slightly acidic, acid (H2SO4) and nitric acid (HNO). The pH of the rainwater therefore decreases below because carbon dioxide (CO2) in the air dissolves in raindrops to form carbonic acid pH 5 and becomes acid rain. (H2CO3). So, pure rainwater is naturally Acid rain in severely polluted places such already slightly acidic. as China has a pH as low as 2.9. gX^\, + N_`Z_Z_\d`ZXcjf]gfcclk`feZXlj\XZ`[iX`e6 ?)JF+ ?EF* jlc]li`ZXZ`[ e`ki`ZXZ`[ Jdfb\ gfcclk`fe `e:_`eX# 8d\i`ZX 8Z`[iX`eZXefecp]Xcc`eZfleki`\jn_\i\k_\i\`jX^i\XkXdflek Xe[ 8Z`[iX`e`jZXlj\[Ypknfb`e[jf]Z_\d`ZXcj#jlc]li[`fo`[\ JF) # Xe[e`kif^\efo`[\j EFo !%K_\j\Z_\d`ZXcjXi\]fle[`ejdfb\ k_Xk`jgif[lZ\[]ifdYlie`e^]fjj`c]l\cj j\\>cfjjXip9ffbc\k) c`b\ ZfXc#fic`hl`[]l\cjjlZ_Xjg\kifcfi[`\j\cn_`Z_Xi\dX[\]ifd Zil[\f`c% 8Z`[iX`e`j]fid\[XjXi\jlckf]k_\Z_\d`ZXcj]ifdgfcclk`fe i\XZk`e^n`k_k_\k`epnXk\i[ifgc\kj`ek_\Zcfl[jkf]fidXZ`[j# n_`Z_k_\e]Xcckf\Xik_XjiX`e% 33 8[\kX`c\[\ogcXeXk`fef]k_\Z_\d`jkipf]XZ`[iX`e]fidXk`fe`j ^`m\e`ek_\Ycl\YXiY\cfnc\]k% !efk\ k_\o`eEFOd\Xej k_Xkj\m\iXc[`]]\i\ek ]fidf]e`kif^\e EF JF) fo`[\j\o`jk# ) `eZcl[`e^e`kif^\e dfefo`[\ EF Xe[ e`kif^\e[`fo`[\ EF) % EF gX^\- , :fdgXi`e^gfcclk`fefeC`_`in`k_Jp[e\pXe[:_`eX Jlcg_li[`fo`[\ JF) `jfe\f]k_\dX`egfcclkXekjk_XkZXlj\ XZ`[iX`eXifle[k_\nfic[%J`eZ\k_\(0.'j^fm\ied\ekcXnj`e dfjk`e[ljki`Xc`q\[Zfleki`\j_Xm\]fiZ\[`e[ljki`\jkfi\[lZ\ JF)\d`jj`fej%K_\LJ8_Xji\[lZ\[`kjfm\iXccJF)\d`jj`fej YpXYflk**j`eZ\(0/'% K_\XeelXcXdflekf]JF)\d`kk\[Ypk_\gfn\igcXekXkC`_`i Y\]fi\k_\^\fk_\idXcgfn\igifa\ZkY\^Xe j\\9ffb\k* nXj `e[\\[hl`k\_`^_ *#0-+kfee\jg\ip\Xi #Ylkefke\Xicp_`^_ \efl^_kfZXlj\XZ`[iX`efeC`_`i%K_\^iXg_Y\cfnZfdgXi\j k_\XeelXchlXek`kpf]JF)\d`kk\[Ypk_\gfn\igcXekXkC`_`i n`k_k_\Xdflekf]JF)\d`kk\[Ypk_\Z`kpf]9\`a`e^#Xe[k_\ ^i\Xk\iJp[e\pXi\X#`ei\Z\ekp\Xij% 8eelXcJF) 200,000 \d`jj`fej 180,000 `e:_`eX# Jp[e\pXe[ 160,000 C`_`i)'',Æ- 140,000 120,000 100,000 80,000 60,000 40,000 20,000 0 Kfee\jJF) g\ip\Xi Beijing9\`a`e^ SydneyJp[e\p C`_`iLihir C`_`iLihir )''- )'',&- )'', )''- C`_`ii\[lZ\jJF)\d`jj`fejkfXhlXik\i JF)`jefk:F) 9plj`e^^\fk_\idXcgfn\iC`_`i_Xji\[lZ\[ :XiYfe[`fo`[\ :F) `jk_\dX`e^Xjk_Xk k_\Xdflekf]JF)\d`kk\[Ypk_\^\e\iXkfij ZXlj\j^cfYXcnXid`e^Xe[Zc`dXk\Z_Xe^\# kffe\hlXik\if]k_\fi`^`eXcXdflek Xe[`j\d`kk\[`e`dd\ej\hlXek`k`\jYp ÇXifle[00(kfee\jg\ip\Xi%:fdgXi\ `e[ljki`XceXk`fej#n`k_k_\LJ8\d`kk`e^ k_`jn`k_k_\Xdflekf]JF)\d`kk\[Ypk_\ _`^_\ihlXek`k`\jk_XeXccfk_\iZfleki`\j%@k mfcZXefKXmlimliXkIXYXlc`e(00+%K_`j `j`dgfikXekkfle[\ijkXe[k_XkXZ`[iX`eXe[ mfcZXefnXj\d`kk`e^XYflk*'#'''kfee\j ^cfYXcnXid`e^Xi\\ek`i\cp[`]]\i\ekgifYc\dj# f]JF)g\i[Xpn_\e`kÔijk\ilgk\[ Xe[Xi\ZXlj\[Yp[`]]\i\ekgfcclkXekj% page Glossary for cloud cycle and acid rain acid / acidity water that has a pH lower (more acidic) than 5 atmosphere the gases that make up the air around us, which extends hundreds of kilometers upwards, but becomes thinner as we go higher. Air is made up of nitrogen (78.08%), oxygen (20.95%), argon (0.39%), and a small amount carbon dioxide (about 0.038%, and rising!), and smaller amounts of various other gases. At sea-level air has a density of 1.266kg/m3. concentration the measure of the amount (usually the weight) of a substance in a particular volume of a liquid or a gas. For example two spoons of sugar in one cup of water is more concentrated than one spoon of sugar in one cup of water. condensation when water changes from a gas form to the liquid form, usually as a result of a decrease in temperature. dissolve when a solid becomes integrated to a liquid after being added to it. disperse to spread out; when particles become further apart from each other. evaporation the process by which water changes from a liquid to a gas. Evaporation is faster at higher temperatures. humid humid air is air that has a large proportion of water vapour in it. litmus paper a type of paper that changes to a particular colour when it is dipped into a liquid depending on whether the liquid is acidic or basic. The colour can be compared to an indicator chart that tells us the pH of the solution. A more accurate way of measuring pH is with a pH meter. pH scale a system of measuring the strength of acids and bases. The pH scale goes from 0 to 14. Substances that are neutral, i.e. not acidic or basic, have a pH of 7. Acids have a pH of less than 7 and bases have a pH of more than 7. The system is based on a set of mathematical calculations relating to the chemistry of acids and bases. pH can be measured using colour-based indicators such as litmus paper, or a pH meter. precipitation the process in which water falls to earth, either as liquid drops (rain) or frozen particles (snow or hail). pollution something that contaminates or defiles the environment. transpiration the process where water is released by the leaves of plants in the process of photosynthesis. toxic poisonous tropics the warmest part of the earth, immediately to the north and south of the Equator. The zone of the tropics extends northward to the Tropic of Cancer, and southward to the Tropic of Capricorn. water vapour the gaseous form of water. When water molecules are floating around freely by themselves in the air. page 6 Where does acid rain occur? Where would the acid rain fall in the picture? Yes, that’s right, on the industrial landscape, but read the blue box below to learn what happens if the wind blows the rain clouds. In unpolluted places the water cycle results in normal rainwater with a pH of around 5.6. In places with a lot of heavy industry, the large amounts of sulfur- containing smoke and smog cause acid rain, which has a pH of 4.6 or less. Movement of acid rain Acid rain clouds can be generated by pollution in one place then blown by the wind to another place before the acid rain actually falls to earth. In the past when acid rain was a serious problem in England, acid rain clouds that were generated by air pollution there were being blown across the sea and the acid rain was falling on countries such as Sweden and Denmark. page Smog Acid rain is only a problem in heavily industrialised parts of and the world, such as the northeastern United States, Eastern pollution in China. Canada, most of Europe, parts of India, Northern and Central China, and Japan. In these countries there are hundreds of power generators the size of the ones at Lihir. There are also many thousands more cars and trucks and many large factories producing air pollution of various kinds. In North America and Europe today acid rain is not such big a problem as it was in the 1970s and 1980s, because governments in those countries have made laws to reduce the amount of sulfur emitted by power plants and factories. But in China acid rain is still a big problem. The famous The link between electricity, pollution and acid rain Earthlights photograph The Earthlights photograph (below) gives us an idea of where below is a the greatest amount of electricity production, and associated panoramic pollution from power plants, is taking place. These places are image of the earth exactly where acid rain has been a problem. Papua New Guinea at night. is one of the least polluted places on earth today.· gX^\(' . :flc[XZ`[iX`e]XccfeC`_`i6 EFFeC`_`i@jcXe[#jlc]li[`fo`[\fZZlijeXkliXccp# `em\ipjdXccXdflekj#`emfcZXe`Z\d`jj`fejXe[j\X jgiXp%K_\jdfb\]ifdk_\C`_`igcXekj`k\\d`kjjfd\ JF)Xe[EF`ekfk_\Xkdfjg_\i\% K_\jk\Xd]ifdk_\d`e\j`k\XcjfZfekX`ejjdXcc Xdflekjf]JF)%?fn\m\i#m\ipcXi^\Xdflekjf] k_\j\Z_\d`ZXcjXi\e\Z\jjXipkfZXlj\XZ`[iX`e% e tell How can w i f the re is a cid rain on Lihir? You could tell by the freshwater fi sh. Acid rain would cause the fi sh in the creeks and rivers to die. J\\gX^\()55 JF JF) EFo ) The pollution being produced by the Lihir diesel generators is usually dispersed (see Leaflet 2) so quickly that it is very unlikely that it would ever cause acid rain. However on some days when there is no wind at all, a tiny cloud can sometimes be seen at the top of the smoke plume above the generators, but it is very unlikely that this cloud would ever get big enough to generate any rain. condensation cloud warm humid air smoke plume from the generators Electricity generation on Lihir Some people might think that acid rain could In reality the total amount of pollution fall around a mine site like Lihir. Compared produced by the diesel generators on Lihir to other places in PNG, Lihir did experience was extremely small compared with the higher levels of air pollution while the diesel amount produced in areas of the world generators were operating at the mine. With where acid rain is a problem. In 1995 PNG clean geothermal power from harnessing the emitted 22,000 metric tonnes of SO2 per steam now replacing these diesel generators, year, which is less than 1/60th of Australia’s (see Booklet 3) air pollution is greatly reduced. current emission rate. (see page 6). page 12 8 The effect of acid rain on the environment Acid rain causes damage to the soil, plants and rivers. How much damage depends on how acidic the rain is, and how much acid the soil, plants and rivers can withstand — this varies quite a lot between different places. Some soils can tolerate quite a lot of acid rain, and so In polluted can some plants. The soils that are most sensitive to industrial acid rain are soils that are already quite acidic. The areas acid plants that are most sensitive are certain kinds of pine rain is common. trees, most of which grow in cold places. When the pH of rivers and lakes falls below about 5, then the fish start to die, along with many other plants and animals. acid rain freshwater pH above 5 freshwater pH below 5 The effect of acid rain on soils Acid rain falling on soil makes the soil more Acidity also reduces the availability of acidic, which decreases its pH. nitrogen in the form of ammonia (NH4). (For more on pH values see Booklet 3) Also, aluminium, which is normally attached When soils become acidic, the availability to clay particles in the soil, becomes dissolved of calcium (Ca), magnesium (Mg) and under acid conditions. In its dissolved form, potassium (K) — important nutrients for aluminium is toxic to plants and animals. plants (see also Booklet 4), is reduced. gX^\(* 0 K`d\kfZ_\Zb_fndlZ_pflËm\c\Xiek 8ejn\ik_\hl\jk`fejY\cfnkfj\\ _fnn\ccpflle[\ijkXe[XccXYflkk_\ ZXlj\Xe[\]]\Zkjf]XZ`[iX`e% ?fn`jefidXciX`e]fid\[6 N_XkZfe[`k`fejZXlj\_`^_\iiX`e]Xcc`e jfd\gcXZ\jk_Xefk_\ij6 N_Xk`jk_\g?f]efidXciX`e6 N_Xk`jk_\g?f]XZ`[iX`e6 N_XkZ_\d`ZXcj`eX`igfcclk`feZXlj\ XZ`[iX`e6 ?fn_XjC`_`ii\[lZ\[\d`jj`fejf]JF)6 N_\i\`ek_\nfic[`jXZ`[iX`eX gifYc\dkf[Xp6 ?Xjk_\`ekif[lZk`fef]^\fk_\idXc gfn\iX]]\Zk\[k_\c`b\c`_ff[f]XZ`[iX`e feC`_`i6 N_Xk`jk_\\]]\Zkf]XZ`[iX`efegcXekj6 Fei`m\ijXe[jki\Xdj6Fejf`cj6 Efn#Xejn\ik_\hl\jk`feXjb\[fe k_\]ifekf]k_`jYffbc\k1 Could smoke from the mine cause acid rain on Lihir?