This article was downloaded by: ["University at Buffalo Libraries"]On: 10 October 2014, At: 11:39Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH,UK

Hydrological Sciences BulletinPublication details, including instructions for authorsand subscription information:http://www.tandfonline.com/loi/thsj19

EFFECTS OF MAN'S ACTIVITIESON GROUNDWATER QUALITY /Les effets des activités del'homme sur la qualité des eauxsouterrainesGEORG MATTHESS aa Institut und Museum der Universität Kiel ,Olshausenstrasse, 40/60 23, Kiel, German FederalRepublicPublished online: 25 Dec 2009.

To cite this article: GEORG MATTHESS (1976) EFFECTS OF MAN'S ACTIVITIES ONGROUNDWATER QUALITY / Les effets des activités de l'homme sur la qualitédes eaux souterraines, Hydrological Sciences Bulletin, 21:4, 617-628, DOI:10.1080/02626667609491678

To link to this article: http://dx.doi.org/10.1080/02626667609491678

PLEASE SCROLL DOWN FOR ARTICLE

Taylor & Francis makes every effort to ensure the accuracy of all theinformation (the “Content”) contained in the publications on our platform.However, Taylor & Francis, our agents, and our licensors make norepresentations or warranties whatsoever as to the accuracy, completeness, orsuitability for any purpose of the Content. Any opinions and views expressedin this publication are the opinions and views of the authors, and are not theviews of or endorsed by Taylor & Francis. The accuracy of the Content shouldnot be relied upon and should be independently verified with primary sourcesof information. Taylor and Francis shall not be liable for any losses, actions,claims, proceedings, demands, costs, expenses, damages, and other liabilitieswhatsoever or howsoever caused arising directly or indirectly in connectionwith, in relation to or arising out of the use of the Content.

This article may be used for research, teaching, and private study purposes.Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expresslyforbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/terms-and-conditions

Dow

nloa

ded

by [

"Uni

vers

ity a

t Buf

falo

Lib

rari

es"]

at 1

1:39

10

Oct

ober

201

4

Hydrological Sciences-Bulletin-des Sciences Hydrologiques, XXI, 4 12/1976

EFFECTS OF MAN'S ACTIVITIES ON GROUNDWATER QUALITY*

GEORG MATTHESS Institut und Museum der Universitàt Kiel, Olshausenstrasse 40/60

23 Kiel, German Federal Republic

Received 7 October 1975

Abstract. The changes in groundwater quality that result from man's activities are reviewed. This paper considers the various geochemical reactions, the biochemical processes and the physical processes that take place as well as the sources of pollution. Suggestions are made for future research a'nd practical guidance given for avoidance of pollution of groundwater or minimizing its effects.

Les effets des activités de l'homme sur la qualité des eaux souterraines

Résumé. On passe en revue des changements de qualité des eaux souterraines qui résultent des activités de l'homme. Ce mémoire tient compte des réactions géochimiques différentes, des processus biochimiques et des processus physiques qui se produisent et aussi des sources de la pollution. On fait des suggestions en vue des recherches futures et on donne quelques indications pour éviter la pollution des eaux souter­raines ou pour réduire au minimum ses effets.

1. INTRODUCTION

Changes, of groundwater quality are caused directly or indirectly by various activities of man. Direct influences emanate from natural or artificial substances which are introduced by man into the geochemical cycle of the earth, and ultimately reach the groundwater zone. Indirect influences should be considered to be those changes of quality which are brought about with­out the addition of substances by man into hydrological, physical and biochemical processes. Transitions occur between the direct and indirect influences, e.g. when artificially recharged and bank filtered river water containing noxious constituents mixes with groundwater.

Polluted groundwater may be defined as groundwater which has been affected by man to the extent that it has higher concentrations of dissolved or suspended constituents than maximum permissible concentrations fixed by national or international standards for potable, industrial or agricultural purposes. As natural groundwater (i.e. not influenced by man) may contain constituents exceeding the standard limits, pollution should be defined in these cases as any increase in the concentration of the respective constituent above its natural variations (Matthess, 1972). Thus, the evidence of man-made changes takes as a prerequisite the inves­tigation of natural groundwater properties and their temporal and spatial variations. The criteria for anthropogenic influences must be chosen in accordance with the prevailing cir­cumstances and the best proof will be the identification of artifical components in ground­water. Natural processes, to which all substances are exposed, may modify the composition of groundwater on its subterranean flowpath. This is the reason for the spatial and temporal limitation of areas affected by pollution or of polluted groundwater zones. However, it also creates difficulties in obtaining clear evidence of anthropogenic influences.

* This paper was presented at the International Symposium on the Geochemistry of Natural Waters, organized by IAHS and IAGC and held at Burlington, Ontario, Canada, 18-20 August 1975.

617

Dow

nloa

ded

by [

"Uni

vers

ity a

t Buf

falo

Lib

rari

es"]

at 1

1:39

10

Oct

ober

201

4

2. GEOCHEMICAL, PHYSICAL AND BIOLOGICAL PROCESSES IN GROUNDWATER INFLUENCED BY MAN

Type, extent and duration of anthropogenic changes of groundwater quality are controlled by the degree of man's influence, the geochemical, physical and biological processes in the ground and the hydrogeological conditions present. The geochemical, physical and biological processes controlling man's influences are:

Geochemical reactions Biochemical processes Physical processes Biophysical processes solution-precipitation organic decomposition dispersion transport of pathogens acid-base reaction cell synthesis filtration filtration of pathogens oxidation-reduction transpiration evaporation complexation gas movement adsorption-desorption 2.1. Geochemical reactions Solution of substances in the ground is generally due to dissolution, degradation and hydra­tion processes. The ability of water to dissolve substances is increased by inorganic and or­ganic acids and an increase in temperature. Solution and precipitation are frequently con­trolled by pH and Eh. Solution of artificial solids may occur in the atmosphere (aerosols) and on and under the ground surface. Resulting concentrations are due to the solubility of the respective substances, the extent of the solid/water interface and the contact time. The solubility of numerous substances dependent on pressure, temperature and co-solutes may be studied in models with the help of chemical thermodynamics (Garrels and Christ, 1965). This approach is valid only for electrolytic solutions, not for colloids. The basis of equili­brium thermodynamics is Gibbs' free energy AG, which is related to the equilibrium coeffi­cient'AT by

AG0 = -RT InK (1)

where R = universal gas coefficient, and T= absolute temperature (°K). As the solid phase surface energy is added to the Gibbs' free energy, it follows that fine-grained material is less stable and thus more soluble than coarse-grained material. This is independent of the kinetic effects of smaller grain-sizes which result in faster equilibration (Langmuir, 1971).

Along subterranean flowpaths, dissolved materials may be precipitated when evaporation and transpiration increase their concentration above the respective saturation limits, e.g. in arid climates, or when groundwaters with different chemical compositions are mixed. The concentration of individual ions may exceed their solubility products, especially for poorly soluble constituents.

Substances with solubilities which are dependent on pH and Eh may be precipitated by groundwaters with different pH and Eh values (e.g. mixtures of groundwater free of oxygen containing ferrous iron with oxygen-bearing groundwater). The Eh conditions may change along the subterranean flowpath of the water. Oxygen-consuming processes e.g. microbial degradation of organic matter, may give rise to oxygen-free reduction zones characterized by the presence of ferrous iron, manganese, ammonia, nitrite and sulphide, the deficiency of nitrate and a diminished content or absence of sulphate (Schwille and Vorreyer, 1969; Golwer et al, 1970). In such reduction zones heavy metals are precipitated as sulphides when sulphide ions are present. When groundwater flows into regions where oxygen supply ex­ceeds the oxygen consumptions, the reduced inorganic materials are oxidized with the preci­pitation of insoluble hydroxides and oxides, especially those of iron and manganese.

Precipitates usually remove other ions from solution. This effect of co-precipitation is important for the fixation of many heavy metals and radioactive substances in the ground, especially in iron and manganese hydrates. The bonding of the co-precipitated substances

618

Dow

nloa

ded

by [

"Uni

vers

ity a

t Buf

falo

Lib

rari

es"]

at 1

1:39

10

Oct

ober

201

4

may be due to one of several possibilities, e.g. solid solution and adsorption. Co-precipitation with iron and manganese hydroxides is predominantly connected with surface adsorption of hydroxide flakes and gelatine (Fôrstner and Millier, 1974).

The solubility may be changed by complexing. The soluble complexes are not taken into account in the pH-Eh-stability field diagrams. In addition to inorganic complexes (hydroxo-, chloro-, sulphato- and phosphato-) there are, in natural systems, organic sub­stances of microbial origin, such as tartaric acid, citric acid, catechol and salycilic acid acting as complexing compounds (Scheffer and Schachtschabel, 1970). Furthermore synthetic complexing compounds, e.g. nitrilotriacetic acid (NTA), may yield stable soluble complexes as in the case where 10 mg/1. NTA «mobilized 24 mg/1. zinc per kg sediment of the Tomo-gonops River, New Brunswick, Canada (Zitko and Carson, 1972).

Water insoluble complexes, e.g. insoluble humic acids, may fix cations (chelation). Such cations cannot be exchanged as adsorped cations. Two-thirds of the positions of the total bond capacity of about 200 to 600 meq. metal ion/100 g humic acid are occupied by chela­tion, the rest are filled by cation exchange capacity (Fôrstner and Miiller, 1974).

Many solid substances in the ground which come into contact with subterranean waters tend to release certain constituents into solution and to remove others from solution. The binding of dissociated and of non-dissociated components of a solution to the surface of solid particles due to intermolecular interchanges is termed adsorption. The equilibrium between the quantity of a substance Cj bound to an adsorbent and the quantity of this sub­stance in solution Cw is described by Freundlich's isothermal equation

where k and n are parameters specific to particular substances. The relation shows that an increase in the concentration of a solution will raise the adsorbed quantity, and a decrease in the concentration will result in desorption.

In the case of exchange between solute and adsorbed ions, the process is termed ion-exchange. Strong adsorbents in rocks include clay minerals, zeolites, iron and manganese hydroxides and hydrates, aluminium hydroxide, the organic substances, especially humic substances. Furthermore, the adsorbing effects of plant roots, micro-organisms and microbial slimes are worthy of mention. Direction, quantity and velocity of ion exchange processes depend on the types and properties of the constituents of the rocks, the kind of adsorbed ions, the kind and concentration of dissolved ions and their complementary ions. The ex­change process between adsorbed and dissolved ions is reversible and may be described by the law of mass action (Garrels and Christ, 1965; Stumm and Morgan, 1970).

Adsorption and ion exchange are important above all for the fixation of chemical and radioactive substances in water in the unsaturated and saturated zones and they are of some importance in the elimination of bacteria and viruses from sub-surface water. Micro-organ­isms are adsorbed particularly on surfaces of fine-grained materials (Butler et al, 1954).

The filtration effect of rocks is a complex physical and chemical phenomenon. It in­cludes the removal of the larger particles by mechanical straining and the adsorption of smaller suspended particles (bacteria, flakes of iron hydroxide etc.). The filtration process may produce, after some time, adhesive gelatineous coatings on the surface of solid particles due to microbial colonies and colloidal materials, which usually improve the filtration effect.

2.2. Biochemical processes Primary organic compounds are decomposed by micro-organisms which obtain from these processes carbon and hydrogen for their cell synthesis. The energy necessary for their meta­bolism is supplied by the degradation of substances rich in energy into simpler compounds, poorer in energy, and finally into C02 and H 2 0 . These reactions take place in aerobic and anaerobic environments although at a slower rate in an anaerobic environment. Under

6 1 9

Dow

nloa

ded

by [

"Uni

vers

ity a

t Buf

falo

Lib

rari

es"]

at 1

1:39

10

Oct

ober

201

4

anaerobic conditions, the micro-organisms receive necessary oxygen by reducing oxygen-bearing compounds, particularly nitrates and sulphates.

The directions of the microbial reactions are controlled by the thermodynamic relations of the respective systems, but proceed under favourable ecological conditions much faster than as pure physical-chemical reactions. Microbial reactions are produced by autochthonic micro-organisms, which are adapted to local underground environments. An increase of nutrients by groundwater pollution produces an increase in microbial population density. Microbial reactions are hydrochemically important in the oxidation and reduction processes of the sulphur, nitrogen, iron, manganese and carbon cycles (e.g. see Matthess, 1973).

Microbial activities may be disturbed by organic and inorganic substances which inhibit their metabolism or kill the micro-organisms. This effect is important for the elimination of microbial pollutants in the ground. Allochthonic micro-organisms, e.g. entrained pathogens, are killed by the antagonistic effects of antibiotic substances liberated by algae, or actino-mycetes, or they serve as nutrients for protozoa and primitive metazoa living in the rock interstices (Schmidt, 1963; Husmann, 1966a,b).

2.3. Physical processes The extensions of an anthropogenically influenced groundwater zone depends on its hydro-geological conditions (Brown, 1961;Deutsch, 1963;LeGrand, 1965; Milde and Mollweide, 1970). The prediction of the effects of anthropogenic interference requires a knowledge of the position of the water table, the hydraulic gradient, the distance of any wells or springs from any hazardous activities and the properties of the rocks, such as adsorption capacity and hydraulic conductivity. The subterranean movement of any pollutant is influenced by the moisture content and water balance in the unsaturated zone, the hydraulic gradient and the water balance in the saturated zone. These parameters are controlled by the volume of water in the system, which depends on climate, topography and hydraulic conductivity. The nature of the rock defines the hydraulic conductivity. In non-indurated porous aquifers, especially sands and gravels of Quaternary and Tertiary age, the groundwater velocity in the interstices is usually less than 1 m/d (rarely some 10 m/d). In fissured and karstified rocks the groundwater movement is faster. Flow velocities up to 8 and 26 km/d have been re­ported (Matthess, 1970).

The propagation of pollutants is, therefore, much faster in fissured and karstified rocks than in non-indurated porous aquifers. The greater width of the interstices in the former enables the subterranean transport of suspended matter (particularly micro-organisms, viruses and substances giving rise to turbidity). Polluted groundwater can be diluted by mix­ing with pure groundwater until the concentrations of the pollutants reach normal levels. The significance of dilution with regard to the limitation of a polluted groundwater plume, when compared with other limiting chemical, biochemical and physical processes, depends on the quantity and quality of mixed waters. Diluting water may be groundwater flowing from the sides or below the pollution plume or seepage from groundwater recharge. The process of mixing may be described by dispersion models which may examine and predict the propagation and limitation of pollutants (Bredehoeft and Pinder, 1972; Fried, 1972; Pinder, 1973).

The gas movement between groundwater and the atmosphere crosses two interfaces which divide the unsaturated zone from the groundwater and the atmosphere. Gas move­ment in the saturated and unsaturated zone is due to diffusion, combined in the ground­water with flow dispersion and in the unsaturated zone with thermal and barometric in­fluences (Golwer and Matthess, 1972). The magnitude and efficiency of the oxygen supply from the atmosphere controls whether there are anaerobic conditions in the groundwater. The reverse gas movement removes the gaseous decay products, nitrogen and CO2 and vol­atile pollutants from the groundwater.

620

Dow

nloa

ded

by [

"Uni

vers

ity a

t Buf

falo

Lib

rari

es"]

at 1

1:39

10

Oct

ober

201

4

2.4. Biophysical processes Pathogens are passively entrained into and within groundwater. Extended propagation is only likely in large fissures and solution holes; yet even in these aquifers the unfavourable ecological conditions and the effect of antagonistic autochthonic organisms in the ground­water should eliminate these germs if the groundwater residence time is long (more than 50 days).

3. VARIOUS IMPACTS BY MAN ON GROUNDWATER QUALITY

A pertinent review of anthropogenic influences should distinguish between direct influences connected with a supply of substances to the observed system, and indirect influences.

3.1. Direct changes: by gaseous, fluid and solid wastes, by manures, pesticides and applica­tion of salt to highways Industrial and domestic flue gases contain mainly C0 2 , S0 2 , and to a lesser extent chlorine, fluorine, and other substances, which can be detected in atmospheric aerosols. All these substances may reach groundwater, dissolved in rain and seepage water.

Anthropogenic increase of atmospheric C02 content will induce only minimal changes in the natural C02-content of groundwater (Matthess, 1973). In contrast precipitation in industrialized areas, where there are considerable emissions of S0 2 , contains much higher S04-concentrations (30 to more than 450 mg/1.) than those in rural areas (less than 15 mg/1.). Other substances, which may reach groundwater via the atmosphere, are bromine (Lininger et ai, 1966), chlorine (Junge, 1963), fluorine (Reimer and Rossi, 1970), lead (Lininger et al, 1966; Golwer, 1973; Golwer and Schneider, 1973) and pesticides (Breiden-bach, 1965; Weibel et al, 1966; Tarrant and Tatton, 1958).

Pollution by gaseous substances may occur in areas of underground gas reservoirs due to leakages through the covering strata and around injection wells.

Organic fluids, which are accidentally introduced into the ground by tanker accidents, and leakage from pipelines or tanks, may influence groundwater quality, when they come into contact with groundwater directly or when they are dissolved in seepage water. Waters containing dissolved or suspended substances, e.g. sewage and polluted surface waters, may act as fluid pollutants.

Among organic fluids, petroleum products (gasoline, kerosene, diesel, heating and motor oil) are possible pollutants. Numerous cases of pollution, some of them lasting several de­cades. have been described in Germany (Schwille, 1964, 1966) and in the USA (Parizek et al, 1971).

Domestic and industrial liquid wastes, with or without treatment, are disposed of into surface waters by infiltration from septic tanks (Miller, 1973), by spreading them as fertil­izers in forests and over croplands (Back, 1973; Sopper and Kardos, 1973; Parizek era/., 1967; Parizek and Myers, 1968; Overman, 1973), by injection into deep geological structures or by drying and incineration, the most expensive method. These methods are not without harmful influences on groundwater quality. Furthermore, uncontrolled leakages from sewers and canals due to corrosion, war damage, earthquakes or subsidence must be taken into account. Randomly occurring leakages of water from sewers, including storm sewers, and the intentional disposal of liquid wastes in urban and industrial areas introduces organic matter into the ground. These will result in the consumption of oxygen and eventually the development of anaerobic zones in which the groundwaters will contain high concentrations of reduced iron and manganese (Motts and Saines, 1969; Langmuir, 1969; Leggat et al, 1972).

Undesirable changes of water quality due to polluted surface waters can be observed in artificial groundwater derived from recharge and bank infiltration of river water. These may

621

Dow

nloa

ded

by [

"Uni

vers

ity a

t Buf

falo

Lib

rari

es"]

at 1

1:39

10

Oct

ober

201

4

be characterized by substances causing unpleasant smells and tastes, and by iron, manganese, ammonia and phenols (Holluta, 1960; Holluta etal, 1968; Standi, 1956). Oilfield brines, containing considerable amounts of salt and dissolved organic substances, may pollute groundwater by leakages from well casings. Most pollution by oilfield brines occurs indirect­ly by infiltration of polluted surface water (Jordan, 1962; Pettyjohn, 1972). There are well known cases of pollution through disposal into septic tanks and disposal pits of municipal and industrial liquid waste including oil, solvents, acids, paint and grease-trap fluids (Leggat et al, 1972), detergents (Bahr and Zimmermann, 1965), phenols (Stundl, 1956), cyanides, chromium, nickel, zinc, cadmium, copper (Csanâdy, 1968), chromium and cadmium (Back andLangmuir, 1974;Pinder, 1973; Perlmutter era/., 1963) and arsenic (Balke etal, 1973). Bacterial pollution of groundwater by septic tanks has been described by Langmuir and Jacobson(1973).

Spray irrigation with liquid wastes and irrigation with sewage may be related to an in­crease of dissolved salts and other substances in groundwater, especially chlorides and sul­phates of alkaline earths and alkali metals. The use of phenol-bearing sewage from gas plants as fertilizer has caused high phenol contents (up to 216 mg/1.) and has influenced smell and taste (Lingelbach et al, 1962). Conversely the underground passage of sewage effluent re­duces the content of nitrogen and phosphate (Cherry etal, 1973; Sopper andKardos, 1973). The factors effective in this elimination (biochemical reactions, adsorption and co-precipita­tion of phosphate with iron hydrates) have been recently investigated in more detail.

A successful economic method for the regeneration of conventionally treated sewage by spreading it on the surface of suitable soils is described by Bouwer(1968). In the ground beneath the shallow infiltration basins, a tremendous microbial population establishes itself, digests the bio-degradable material, kills off the entrained coliform bacteria and other micro­organisms, and decreases the contents of phosphorus, boron and heavy metals considerably.

Solid wastes, deposited above or beneath the ground surface are leached by rain, seepage or groundwater. This material comprises the bulk of municipal and industrial solid wastes and sludges, garbage, construction rubble, ashes, slags and residues of foundry and mining activities.

At present, solid wastes and sludges are usually disposed of by controlled dumping (tipping), by composting or by incineration. Composting creates a usable compost by the biological digestion of organic refuse, especially garbage. Soluble constituents may be leached by rain and seepage water when spread on cropland or forest soils. Incineration decreases the volume of solid wastes. It should be mentioned that many wastes cannot be incinerated or composted and that such methods yield residues, slags and ashes with soluble components, which may be leached. The hazards from exhaust gases of incineration furnaces have still not been completely investigated. The disposal of solid wastes involves their storage using different measures which depend on the degree of environmental hazard. Pathogenic and poisonous materials must be isolated from the environment by natural or artificial seals (as in salt mines or in deep oil or gas structures). The majority of waste materials may be dumped, as a mound, in quarries, gravel excavations or natural depressions. The soluble con­stituents are leached by seepage or groundwater. The concentrations of solutes in the seepage water and groundwater depend on the movement and quantity of groundwater and soil moisture, on the nature of the waste materials, the manner of dumping and on the processes within the dumped materials. It must be emphasized that the quality of seepage waters dif­fers considerably from the underlying groundwater. The seepage which originates from the refuse is, of course, highly concentrated. In the ground, however, the geochemical, biological and physical processes described in section 2 bring about an improvement of water quality.

Municipal or industrial landfill sites have caused numerous examples of groundwater pollution, e.g. Apgar and Langmuir(1971), Birk etal. (1973), Emrich and Landon (1971), Golweiet al (1970, 1972a), Hughes et al (1969, 1971), Lôhnert (1969), Nôring et al. (1968), Pettyjohn (1972) and Siebert and Werner (1969).

622

Dow

nloa

ded

by [

"Uni

vers

ity a

t Buf

falo

Lib

rari

es"]

at 1

1:39

10

Oct

ober

201

4

The use of manures increases the quantity of soluble salts in the soil by direct supply of fertilizers containing chlorides, sulphates, nitrates and phosphates of potassium, calcium, magnesium, ammonia and sodium in varying proportions and by the supply of organic matter and soluble salts (especially chlorides and sulphates) in manures such as dung and liquid manure. Therefore, groundwaters beneath agricultural areas have higher salt contents than those beneath forest areas with comparable hydrogeological conditions (Nôring, 1951 ; Matthess, 1958). Some interest from this health aspect has arisen in the last few years due to the increased concentration of nitrates in groundwaters of intensively cropped areas devoted to horticulture and vineyards (Harth, 1969; Schneider, 1964; Schwille, 1969; Schmidt, 1974).

It should be mentioned that the application of lime to crops induces a release of soluble sulphate in the soil due to intensified activity of soil bacteria (Pfaff, 1937; Kurmies, 1957). Also the release of calcium ions by ion-exchange after fertilizing with potassium salts in­creases the content of alkaline earth ions in groundwater.

Pesticides used in agriculture and forestry for the control of detrimental organisms are mainly synthetic organic compounds. These pesticides (mostly poorly soluble) are generally adsorbed to a great extent in the soil, where they degrade after some time. Nevertheless pesticides are occasionally detected in groundwaters e.g. hexachlorocyclohexane (Stundl, 1956), selinon (Lingelbach and Kiihn, 1965), organic pesticides (Faust and Aly, 1964; Bonde and Urone, 1962; Eldridge, 1963; Quentin et al, 1973). Generally such pollution only oc­curs when pesticides can reach the groundwater without passing through the protecting soil cover e.g. where water sinks occur or where liquid wastes are injected into rocks.

Salinity of groundwater may be increased by the application of salt for de-icing and to encourage the melting of snow on highways (Agie, 1974; Dowst, 1967; Golwer, 1973; Toler and Pollock, 1974). This man-made deterioration will be more serious in the smaller recharge areas and in areas of intensive salt application.

3.2. Indirect changes: de-watering or irrigation of sous, the lowering of the groundwater table in connection with mining, civil engineering works and water supply activities, and as a result of pumping bank-filtered river water or artificial recharge De-watering of soil in agricultural reclamation gives rise to changes in the Eh-conditions. The improved supply of oxygen accelerates biodégradation of organic matter, and enables oxida­tion of sulphides to sulphates and free sulphuric acid; displacing the Eh into the acid range. Changes of this kind are observed in reclaimed coastal marshlands (Calvert and Ford, 1973).

Agricultural irrigation may bring about an increase of salt and nitrate contents and col­ouring of groundwater (Eldridge, 1963). The increase in concentrations is due to évapotrans­piration. It will be highest when the irrigation water is pumped from wells onto neighbouring irrigated cropland, thereby hastening the local water cycle. When large amounts of ground­water are pumped the salt will be concentrated as in isolated basins (Hem, 1970).

Besides évapotranspiration, an increase in the water temperature, biochemical processes, leaching, erosion, ion exchange, sorption, filtration and chelation, influence the changes of groundwater quality in connection with irrigation (Anonym, 1969).

The agricultural treatment of the soils stimulates enforced activity of soil organisms which thereby increase the C02 -content and thus increase the solubility capacity of seepage water for alkaline earth carbonates (Matthess, 1973).

The lowering of the groundwater table due to mining activities changes the geochemical conditions in the ground. Access of atmospheric oxygen oxidizes sulphides resulting in an increase of sulphate content. The generally acid mine waters (pH 3-4) may have considerable contents of dissolved heavy metals (Biesecker and George, 1966; Lindgren, 1933; Matthess, 1974). The cessation of mining does not stop the pollution, which may continue for many decades.

The velocity with which this process is effected is comprehensively described in an example by LeGrand (1958). A well drilled into a pyrite-bearing sericite schist in North

623

Dow

nloa

ded

by [

"Uni

vers

ity a

t Buf

falo

Lib

rari

es"]

at 1

1:39

10

Oct

ober

201

4

Carolina was pumped for 13 months with a considerable drawdown. After pumping stopped and the groundwater returned to its original level it had a sulphate content of 1330 mg/1. (compared with a natural concentration of 13 mg/1.), an iron content of 365 mg/1. and the pH had dropped to 2.5.

Artificial recharge and pumping of bank-filtered river water uses surface waters which may be polluted by man. An important factor is that entrained organic substances may cause reducing conditions in the ground leading to the characteristic dissolution of iron and man­ganese (Kôlle and Sontheimer, 1969; Back and Langmuir, 1974). The infiltration or injec­tion of warm surface waters which have been used for cooling purposes, may change the groundwater quality because of an increased capacity to dissolve constituents in the rocks.

The pumping of groundwater near a coastline may cause sea-water encroachment, especially when the fresh-water body is overpumped. Examples of this phenomenon are known from many coasts, e.g. in the USA (Todd, 1960), Israel (Jacobs and Schmorak, 1960) and in Europe.

The development of poorly oxygenated groundwater zones in urbanized and industrial­ized zones is caused by the presence of city pavements and buildings, which prevent infiltra­tion of oxygenated water or the supply of oxygen by gas exchange between the atmosphere and the soil air (Back and Langmuir, 1974).

It is evident that the effects of different human activities may superimpose themselves, either augmenting or attenuating their noxious impact, e.g. Emrich and Landon (1971) de­monstrated the intensified pollution by solid wastes deposited in abandoned open-cast coal mines directly on permeable fractured bedrock.

4. CONCLUSIONS

4.1. Tasks for future geochemical activities The evaluation of various effects of man's activities on groundwater quality requires a know­ledge of natural background concentrations, their temporal and spatial variations, because the proof of an anthropogenic influence is often only possible by comparison with the natural background.

Knowledge of natural background concentrations may sometimes be a useful argument for fixing maximum permissible concentrations of various substances. Concentrations are known of many substances which produce acute diseases, but judgement of long-term health risks is much more difficult to assess. A possible argument for the acceptance of long-term tolerable limits is to adopt the natural background content to which organisms have been exposed since the beginning of biological time and to which they have adapted themselves. Because the natural background for many substances is not known well enough, it is neces­sary to augment our knowledge about them by exact geochemical investigations of natural unpolluted groundwaters.

4.2. Possibilities for geochemistry The artificial supply of substances to terrestrial geochemical cycles provide new possibilities for the geochemist to enlarge the knowledge of effective geochemical reactions. This is pos­sible because certain characteristic substances, which may be used as tracers owing to their chemical composition or properties as isotopes, can be detected in any part of the hydro-logical cycle.

4.3. Analytical problems—cooperation The detection of many organic or inorganic substances which are only abundant in very small concentrations or only in traces needs specialized analytical techniques and very ex-

624

Dow

nloa

ded

by [

"Uni

vers

ity a

t Buf

falo

Lib

rari

es"]

at 1

1:39

10

Oct

ober

201

4

pensive equipment. One way of overcoming individual shortcomings is through the coopera­tion of different specialized analytical teams, which investigate, with the same samples, all interesting questions. Some successful attempts have been made along these lines through private initiatives although such cooperation should be on a national or an international level. It seems that IAGC should encourage such cooperation.

4.4. Practical objectives The variety of possible anthropogenic influences on groundwater quality is so great as to pose an extreme challenge, which is occasionally met in legal texts (e.g. Wasserhaushalts-gesetz of the German Federal Republic of 27 July 1957, §34,2). Instead the aim should be to minimize anthropogenic influences as far as possible and to confine groundwater pollu­tion to small areas. To attain this objective, the following suggestions are formulated:

(1) Characteristics of the different kinds of anthropogenic pollution should be listed, from which a guide can be prepared to the chemical and physical measurements which can be carried out to identify the nature of any pollution. The extent of the analyses necessary will depend on the nature of the pollution. If only one or two substances are involved, then the necessary determinations can be restricted to a few parameters. If pollution is due to many substances, many different data will be required to describe the effects; then it may be possible to identify properties which characterize special cases.

(2) Waste materials should be recycled and re-used as much as possible. They are com­monly too valuable to be discarded.

(3) Choosing methods and sites for waste disposal should include consideration of hydrochemical and hydrogeological aspects (Golwer et al, 1972b; Parizek, 1973).

(4) More foresight should be given to the application of fertilizers and their effect on groundwater quality. Experiments to develop fertilizers 'harmless' to the environment should be undertaken, along with advice regarding their deployment as to quantities to be used and seasonal timing of their application.

(5) Legal control of the use of pesticide should depend on their behaviour in the en­vironment. Only pesticides that are degraded after some residence time in the soil should be used.

(6) Substances applied to highways for de-icing are usually inorganic salts. Economic, degradable de-icing substances should be developed and used.

(7) Consideration should be given as to whether artificial modifications of the ground­water regime, (e.g. development for agricultural or water supply purposes, the infiltration of surface water or the de-watering of parts of the ground) are likely to change the oxidation-reduction conditions and thus the groundwater quality.

REFERENCES Agie, J. (1974) Pollution des nappes aquifers par les sels de déneigement. Mem. Int. Assoc. Hydrogeol. 10,

7-9. Apgar, M.A. and Langmuir, D. (1971) Ground-water pollution potential of a landfill above the water-table.

Ground Water 9, 76-96. Back, W. (1973) Inorganic geochemical considerations for disposal of municipal sewage by spray irrigation.

Proceedings of the 1973 Workshop, University of Florida, pp. 187-200. Back, W. and Langmuir, D. (1974) Influence of near-surface reactions and processes on chemical character

of ground water: A review of selected experiences in the United States. Mem. Int. Assoc. Hydrogeol. 10,31-37.

Bahr, H. and Zimmermann, W. (1965) Die Wanderung von Detergentien im Boden. Arch. Hyg. Bakteriol. 149 (7/8), 620-626.

Balke, K.-D., Kussmaul, H. and Siebert, G. (1973) Chemische und thermische Kontamination des Grund-wassers durch Industrieabwâsser. Z. dt. Geol. Ges. 124,447^160.

Biesecker, J.E. and George, R. (1966) Stream quality in Appalachia as related to coal-mine drainage, 1965, US Geol. Survey Circ. 526.

625

Dow

nloa

ded

by [

"Uni

vers

ity a

t Buf

falo

Lib

rari

es"]

at 1

1:39

10

Oct

ober

201

4

Birk, F., Geiersbach, R. and Miiller, W. (1973) Die Auswirkungen der Verkippung und Lagerung von cya-nidhaltigen Hàrtesalzen in Bochum-Gerthe auf das Grund- und Oberflâchenwasser. Z. dt. Geo!. Ges. 124,461-473.

Bonde, E.K. and Urone, P. (1962) Plant toxicants in underground water in Adams County, Colorado. Soil Sci. 93,353-356.

Bouwer, H. (1968) Putting waste water to beneficial use-the flushing Meadows Project. Proceedings of the 12th Arizona Watershed Symposium, Phoenix, pp. 25-30.

Bredehoeft, J.D. and Pinder, G.F. (1972) The application of transport equations to a groundwater system. Int. Geol. Congress 11, 255-263.

Breidenbach, A.W. (1965) Pesticides residues in air and water. Arch. Environ. Health 10 (6), 827-830. Brown, R.H. (1961) Hydrologie factors pertinent to groundwater contamination. US Public Health Service,

Technical Report W 61-5, 7-20. Buchan, S. and Key, A. (1965) Pollution of ground water in Europe. Bull. WHO 14, 949-1006. Butler, R.G., Orlob, G.T. and McGauhey, P.H. (1954) Underground movement of bacterial and chemical

pollutants. /. Amer. Water Works Assoc. 46 (2), 97-111. Calvert, D.V. and Ford, H.W. (1973) Chemical properties of acid-sulfate soils recently reclaimed from

Florida marshland. Soil Sci Amer., Proc. 37, 367-370. Cherry, R.N., Brown, D.P., Stamer, J.K. and Goetz, C.Z. (1973) Hydrobiochemical effects of spraying

waste treatment effluent in St. Petersburg, Florida. Proceedings 1973 Workshop, University of Florida, pp. 170-186.

Csanâdy, M. (1968) Ausbreitung der Schwermetall- und Cyanidverunreinigung im Grundwasser. Hidrol. Kozl. 48 (1), 32-38.

Deutsch, M. (1963) Ground-water contamination and legal controls in Michigan. US Geol. Survey Water Supply Paper 1961.

Dowst, R.B. (1967) Highway chloride application and their effects upon water supplies. /. New England Water Works Assoc. 1,63-67.

Eldridge, E.F. (1963) Irrigation as a source of pollution./. Wat. Poll. Control Fed. 35 (5), 614-625. Emrich, G.H. and Landon, R.A. (1971) Investigations of the effects of sanitary landfills in coal strip

mines on ground water quality. Pa. Bureau of Water Quality Management 30. Faust, S.D. and Aly, O.M. (1964) Water pollution by organic pesticides./. Amer. Water Works Assoc. 56

(3), 267-279. Fôrstner, U. and Miiller, G. (1974) Schwermetalle in Fliissen und Seen als Ausdruck der Umweltver-

schmutzung: Springer, Berlin-Heidelberg-New York. Fried, J.J. (1972) Some recent applications of the theory of dispersion in porous media. Proceedings of the

2nd Symposium oflAHR, vol. 2, pp. 722-731, Guelph, Ontario. Garrels, R.M. and Christ, Ch. L. (1965) Solutions, Minerals, and Equilibria: Harper and Row, New York-

Evanston-London: and Weatherhill, Tokyo. Golwer, A. (1973) Beeinflussung des Grundwassers durch Strassen. Z. dt. Geol. Ges. 124,435-446. Golwer, A., Knoll, K.H., Matthess, G., Schneider, W. and Wallhâusser, K.H. (1972a) Mikroorganismen im

Unterstrom eines Abfallplatzes. Gesundh.-Ing. 93, 142-152. Golwer, A. and Matthess, G. (1972) Die Bedeutung des Gasaustausches in der Grundluft fiir die Selbst-

reinigungsvorgànge in verunreinigten Grundwàssern. Z. dt. Geol. Ges. 123, 29-38. Golwer, A., Matthess, G. and Schneider, W. (1970) Selbstreinigungsvorgange im aeroben und anaeroben

Grundwasserbereich. Vom Wasser 36, 64-92. Golwer, A., Matthess, G. and Schneider, W. (1972b) Contamination de l'eau souterraine par des depots de

déchets et implications pour les méthodes d'évacuation des residues. Tribune Cebedeau 25, 347, 428-433.

Golwer, A. and Schneider, W. (1973) Belastung des Bodens und des unterirdischen Wassers durch Strassen-verkehr. Gas-u. Wasserf. 114, 154-165.

Harth, H. (1969) Der Einfluss von Land- und Forstwirtschaft auf den Grundwasserchemismus. Dt. ge-wasserkdl. Mitt., Sonderh. 58-62.

Hem, J.D. (1970) Study and interpretation of the chemical characteristics of natural water. 2. Aufl., US Geol. Survey Water Supply Paper 1473.

Holluta, J. (1960) Geruchs- und Geschmacksbeeintràchtigung des Trinkwassers-Ursachen und Bekâmp-fung. Gas- u. Wasserf. 101,1018-1023, 1070-1076.

Holluta, J., Bauer, L. and Kôlle, W. (1968) Uber die Einwirkung steigender Flusswasserverschmutzung auf die Wasserqualitat und die Kapazitat der Uferfiltrate. Gas- u. Wasserf. 109 (50), 1406-1409.

Hughes, G.M., Landon, R.A. and Farvolden, R.N. (1969) Hydrogeologic data from four landfills in North­eastern Illinois. Environ. Geol. Notes 26, 111. State Geol. Survey, Urbana.

Hughes, G.M., Landon, R.A. and Farvolden, R.N. (1971) Hydrogeology of Solid Waste Disposal Sites in Northeastern Illinois: 111. State Geol. Survey and US Environmental Protection Agency.

Husmann, S. (1966a) Versuch einer ôkologischen Gliederung des interstitiellen Grundwassers in Lebens-bereiche eigener Pràgung. Arch. Hydrobiol. 62 (2), 231-368.

Husmann (1966b) Die Organismen gemeinschaften der Sandluckensysteme in naturlichen Biotopen und Langsamsandfiltern. Veroffentl. hydrol. Forschungsabt. Dortmunder WasserwerkeAG 9, 93-113.

626

Dow

nloa

ded

by [

"Uni

vers

ity a

t Buf

falo

Lib

rari

es"]

at 1

1:39

10

Oct

ober

201

4

Jacobs, M. and Schmorak, S. (1960) Salt water encroachment in the coastal plain of Israel. In Subter­ranean Water (Proceedings of the General Assembly of Helsinki I960), pp. 403-423 : IAHS Publ. no. 52.

Jordan, D.G. (1962) Ground water contamination in Indiana./. Amer. Water Works Assoc. 54, 1213-1220. Junge, E. (1963) Air Chemistry and Radioactivity: Academic Press, New York-London. Kôlle, W. and Sontheimer, H. (1969) Die Problematik der Grundwasserverschmutzung der Mineralôl-

substanzen. Brennstoff-Chemie 50 (4), 123-129. Kurmies, B. (1957) Ùber den Schwefelhaushalt des Bodens. Phosphorsàure 17 (5/6), 258-278. Langmuir, D. (1969) Iron in ground-water of the Magothy and Raritan Formations in Camden and Bur­

lington Counties, New Jersey. NJDept. Conserv. and Econ. Devel, NJ Water Res. Circ. 19. Langmuir, D. (1971) Particle size effect on the reaction Goethite= Hematite+ Water. Amer. J. Set 271,

147-156. Langmuir, D. (1972) Controls on the amounts of pollutants in subsurface waters. Earth Min. Sci, The Pa.

State Univ. 42 (2), 9-16. Langmuir, D. and Jacobson, R.L. (1973) Undersized lots invite polluted well water. Res. College of Earth

and Mineral Sci, Pa. State Univer., University Park, Pa. Leggat, E.R., Blakey, J.F. and Massey, B.C. (1972) Liquid waste disposal at the Linfield Disposal Site,

Dallas, Texas. US Geol. Survey Open-file Report. LeGrand, H. E. (195 8) Chemical character of water in the igneous and metamorphic rocks of North

Carolina. Econ. Geol. 53,178-189. LeGrand, H.E. (1965) Patterns of contaminated zones of water in the ground. Wat. Resour. Res. 1 (1),

83-95. Lindgren, W. (1933) Mineral Deposits (fourth edition): McGraw-Hill, New York-London. Lingelbach, H. and Kiihn, H. (1965) Auswirkungen von Herbiziden auf Grund- und Oberflàchenwàsser.

Fortschr. Wasserchemie und Grenzgeb. 3,153-157. Lingelbach, H., Saalbreiter, R. and Kiihn, H. (1962) Verschmutzung von Trinkwasserversorgungsanlagen

durch Gaswasser. Z. Ges. Hyg. u. Grenzgeb. 8 (10), 761-767. Lininger, R.L., Duce, R.A., Winchester, J.W. and Matson, W.R. (1966) Chlorine, bromide, iodine, and lead

in aerosols from Cambridge, Massachusetts./. Geophys. Res. 71 (10), 2457-2463. Lôhnert, E. (1969) Grundwasserverunreinigungen im Elbe-Tal (Freie und Hansestadt Hamburg). Gas- u.

Wasserf. 110,1171-1177. Matthess, G. (1958) Geologische und hydrochemische Untersuchungen in der ôstlichen Vorderpfalz

zwischen Worms und Speyer. Notizbl. hess. L.-Amt Bodenf. 86, 335-378. Matthess, G. (1970) Beziehungen zwischen geologischem Bau und Grundwasserbewegung in Festgesteinen.

Abh. hess. L.-Amt Bodenf. 58. Matthess, G. (1972) Hydrogeologic criteria for the self-purification of polluted groundwaters. Intern.

Geol. Congress 11, 296-304. Matthess, G. (1973) Die Beschaffenheit des Grundwassers: Bomtraeger, Berlin-Stuttgart. Matthess, G. (1974) Heavy metals as trace constituents in natural and polluted groundwaters. Geol. en

Mijnbouw 53 (4), 149-155. Milde, G. and Mollweide, H.-U. (1969) Die wichtigsten Verschmutzungsgefahren fur Grundwasserlager-

stâtten. Z. Angew. Geol. 15, 17-25. Milde, G. and Mollweide, H.-U. (1970) Hydrogeologische Faktoren bei der Grundwasserverunreinigung.

Wasserwirtsch.-Wassertechnik 20, 234-237. Miller, J.C. (1973) Nitrate contamination of the water-table aquifer by septic tank systems in the Coastal

Plain of Delaware. Rural Environ., Conf, Warren, Vermont. Motts, W.S. and Saines, M. (1969) The occurrence and characteristics of ground-water contamination in

Massachusetts. Univ. of Mass., Amherst, Publ. 7, Water Res. Centre. Noring, F. (1951) Einfliisse der Kunstdiingung auf den Chemismus des Grundwassers. Gesundh.-Ing. 72,

190-191. Nôring, F„ Farkasdi, G., Golwer, A., Knoll, K.H., Matthess, G. and Schneider, W. (1968) Uber die Abbau-

vorgânge von Grundwasserverunreinigungen im Unterstrom von Abfalldeponien. Gas- u. Wasserf. 109, 137-142.

Overman, A.R. (1973) Landspreading municipal effluent and sludge in Florida. Proceedings of the 1973 Workshop, University of Florida.

Parizek, R.R. (1973) Site selection criteria for wastewater disposal soils and hydrogeologic considerations. In Recycling Treated Municipal Waste-Water and Sludge through Forest and Cropland (edited by W.E. Sopper and L.T. Kardos), pp. 95-147: Pa. State University.

Parizek, R.R., Kardos, L.T., Sopper, W.E., Myers, E.A., Davis, E.D., Farrell, M.A. and Nesbitt, J.B. (1967) Waste water renovation and conservation. Pa. State Univ. Studies, 23, Univ. Park.

Parizek, R.R. and Myers, E.A. (1968) Recharge of groundwater from renovated sewage effluent by spray irrigation. Proceedings of the 4th American Water Resources Conference, New York, pp. 426-443.

Parizek, R.R., White, W.B. and Langmuir, D. (1971) Hydrogeology and Geochemistry of Folded and Faulted Rocks of the Central Appalachian Type and Related Land-use Problems: Guidebook of Geol. Soc. Amer.

627

Dow

nloa

ded

by [

"Uni

vers

ity a

t Buf

falo

Lib

rari

es"]

at 1

1:39

10

Oct

ober

201

4

Pettyjohn, W.A. (1972) Water Quality in a Stressed Environment: Burgess Publ. Corp., Minneapolis. Perlmutter, N.M., Liber, M. and Frauenthal, H.L. (1963) Movement of waterborne cadmium and hexa-

valent chromium wastes in South Farmingdale, Nassau County, Long Island, New York. US Geol. Survey Prof. Paper 475-C, 179-184.

Pfaff, C. (1937) Ùber Lysimeter-Versuche. Der Forschungsdienst, N.F. Deutsche Landwirtsch. Rdschau, Suppl. 6, p. 102-114.

Pinder, G.F. (1973) A Galerkin-finite element simulation of groundwater contamination on Long Island. Wat. Resour. Res. 9,1657-1669.

Quentin, K.-E., Weil, L. and Udluft, P. (1973) Grundwasserverunreinigungen durch organische Umwelt-chemikalien. Z. dt. Geol. Ges. 124,417-424.

Reimer, H. and Rossi, Th. (1970) Zur Emission von Chlorwasserstoff bei der Verbrennung von Hausmull. Mull undAbfall 2 (3), 71-74.

Scheffer, F. and Schachtschabel, P. (1970) Lehrbuch der Bodenkunde (seventh edition): Enke, Stuttgart. Schmidt, K. (1963) Die Abbauleistungen der Bakterienflora bei der Langsamsandfiltration und ihre Be-

einflussung durch die Rohwasserqualitàt und andere Umwelteinfliisse. Veroff. Hydrol. Forsch. Abt. Dortmunder Stadtwerke AG., Diss. 5.

Schmidt, K.D. (1974) Nitrates and groundwater management in the Fresno-Urban-Area. /. Amer. Water Works Assoc. 66, 146-148.

Schneider, H. (1964) Geohydrologie Nordwestfalens: Schmidt, Berlin-Konradshôhe. Schwille, F. (1964) Die 'hydrologischen' Grundlagen fur die Untersuchung, Beurteilung und Sanierung

von Mineralôlkontaminationen des Untergrundes. Dt. gewàsserkdl. Mitt. 8 (1), 1-16. Schwille, F. (1966) Die Kontamination des Untergrundes durch Mineralôl-ein hydrologisches Problem.

Dt. gewàsserkdl. Mitt. 10 (6), 194-207. Schwille, F. (1969) Hone Nitratgehalte in den Brunnenwassern der Moseltalaue zwischen Trier und

Koblenz. Gas- u. Wasserf. 110 (2), 35-44. Schwille, F. and Vorreyer, C. (1969) Durch Mineralôl 'reduzierte' Grundwàsser. Gas- u. Wasserf. 110

(44), 1225-1232. Siebert, G. and Werner, H. (1969) Bergeverkippung und Grundwasserbeeinflussung am Niederrhein.

Fortschr. Geol. Rehinld. u. Westf. 17, 263-278. Sopper, W.E. and Kardos, L.T. (editors) (197'3) Recycling Treated Municipal Waste-water and Sludge

through Forest and Cropland: Pa. State University Press. Stumm, W. and Morgan, J.J. (1970) Aquatic Chemistry: Wiley, New York-London-Sydney-Toronto. Stundl, K. (1956) Behinderung der bakteriellen Abbauvorgânge im Boden. Gas-Wasser-Wàrme 10 (12),

317-321. Tarrant, K.R. and Tatton, J.O.G. (1968) Organochlorine pesticides in rainwater in the British Isles.

Nature 219, 725-727. Todd, D.K. (1960) Salt water intrusion of coastal aquifers in the United States. In Subterranean Water

(Proceedings of the General Assembly of Helsinki 1960), pp. 452-461: IAHS Publ. no. 52. Toler, L.G. and Pollock, S.J. (1974) Retention of chloride in the unsaturated zone. US Geol. Survey J.

Res. 2,119-123. Weibel, S.R., Weidner, R.B., Cohen, J.M. and Christianson, A.G. (1966) Pesticides and other contaminants

in rainfall and runoff./. Amer. Water Works Assoc. 58,1075-1084. Zitko, V. and Carson, W.V. (1972) Release of heavy metals from sediments by nitrilotriacetic acid (NTA).

Chemosphere 3, 113-118. Anonym (1969) Characteristics and Pollution Problems of Irrigation Return Flow: Robert S. Kerr Water

Res., Cen. Ada, Okla.

628

Dow

nloa

ded

by [

"Uni

vers

ity a

t Buf

falo

Lib

rari

es"]

at 1

1:39

10

Oct

ober

201

4