The Scientific Basis of Marine Pollution Prevention Strategies

Abstract

Prevention of marine pollution, particularly in semi-enclosed seas, embayments and areas with limited exchange of water, requires a well conceived and harmonized legal system, specified standards, a monitoring programme, and effective control and enforcement capabilities. This comprehensive approach is often called a strategy. Three generations of strategies have been devised and applied historically in Europe and North America, each a step further in integrating environmental protection, technical advancement and economic capabilities. the overpowering socio-economic problems of transition from a centrally planned to a market economy, a task facing a dozen central and eastern European coastal states, compound the problem of application of an integrated approach.

No management strategy can achieve its set goals unless based on scientific evidence. the data base has to offer information on two basic questions, one specific and one of a general nature.

The specific question is: Has the area under consideration some features, an activity, or one or more living species, which must be protected at any cost? the answer to this question will invoke the precautionary principle into strategic considerations, and leads to the general question: What is the carrying (= assimilative or environmental) capacity for each activity and for the discharge of each contaminant into the impacted area? Answers to these questions lead to the choice of the strategy for environmental management.     

Environmental Pollution Due to Natural Factors: A Case Study in A Volcanic Area (Vulcano Island, Italy)

A major influence on the environment of active volcanic areas is expected from continuous input of chemical species pertaining to fumarolic activities occurring during inter-eruptive intervals.

The systematic investigations carried out during thirteen years in the island of Vulcano (Italy) showed also substantial contributions to phreatic waters and soils of minor constituents and trace metals from volcanic rocks with no negligible influence on growing crops.

Greater extents of these phenomena have been observed for products of hydromagmatic volcanic activity or of long-lasting weathering processes.     

Strategy for the Control of Land-Based Sources of Marine Pollution in the Wider Caribbean Region

The pollution of the marine environment caused by land-based sources threatens or impairs the health of the ecosystems and the value of human uses of the coastal waters. the Contracting Parties to the Convention for the Protection and Development of the Marine Environment of the Wider Caribbean Region agreed to take all appropriate measures to prevent, reduce and control pollution. in the first meeting of the Contracting Parties, the development of a protocol on the control of marine pollution from land-based sources was recommended as a measure to protect the marine environment.

A small group of experts from the Caribbean Region formulated a strategy for controlling land-based sources of marine pollution. Due to the diverse nature, resources and capabilities of the countries comprising the Region, the pollution control strategy suggested by the group of experts included the following techniques or their most appropriate combination: (1) pollution prevention measures, (2) effluent limitations, (3) water quality limitations, (4) environmental planning, and (5) best management practices. the desirable control strategy should be based on a system of discharge permits in the case of point source pollution, which includes effluent and water quality limitations. the technology based effluent limitations could be applied as a short-range strategy to control pollution from industrial and domestic point source discharges. the use of water quality standards could become part of a long-range strategy for controlling point sources. for nonpoint sources, it would be virtually impossible to develop effluent limitations. Thus, the implementation of best management practices and effective environmental planning would be the most reasonable control strategy for non-point sources. However, pollution prevention measures could consist of a “black list” of substances that should be completely banned, and a “grey list” for those that should be strictly limited. These lists should be adopted or appropriately modified for the conditions of the Wider Caribbean Region.

The development of control based on the water quality of the receiving body of water involves the collection and analysis of effluent and ambient data to develop water quality based permit limits and to assess compliance with these permits. Finally, any marine pollution control strategy developed by the countries of the Region should be mutually agreed upon and implemented within a period of ten years from the ratification of a protocol on land-based sources of marine pollution.     

Effect of Pollution On the Occurrence, Distribution and Sulphur Transformation Ability of the Thiobacilli in the River Ganga

The occurrence, distribution and nature of ambient thiobacilli along with their ability to oxidize different sulphur species under simulated natural and in vitro culture conditions were studied in the polluted and unpolluted sites of the River Ganga.

Thiobacillus thioparus, T. thiooxidans and T. denitrificans were isolated from the river water. the former two occurred in both polluted and unpolluted sites, while T. denitrificans occurred in polluted areas only. the paper pulp mill effluent discharge area contained the highest population of T. thioparus. the sewage drainage area showed relatively higher populations of T. thiooxidans and T. denitrificans.

The present study revealed that only biological oxidation of either thiosulphate or elemental sulphur occurred in the river water. All the thiobacilli screened oxidized thiosulphate, and three-fourths of them oxidized elemental sulphur. Some strains were found to be very good acidifiers. in spite of such acidification by the ambient thiobacilli, the pH of the river water remained alkaline. the specific rates of thiosulphate (0.18 -0.51 μMmolh^-1 mg^-1 cell) and sulphur (1.3 - 6.2 Normality day^-1 mg^-1 biomass) oxidations under simulated natural condition were found to be higher in polluted areas when compared with the unpolluted one (sulphur: 0.8 - 1.0 Normality day^-1 mg^-1).

Further, addition of thiouslphate or elemental sulphur in the river water in simulated in vitro condition resulted in the increase of respective oxidation rates. the variations in the natae of pollutants discharged into the river water influenced the oxidation rate of thiosulphate or sulphur.     

Plastics in the Marine Environment: Problems and Solutions

Plastics debris is known to be present in all of the world's oceans, and on most amenity beaches, although comparatively little data are available to provide reliable information on the extent of damage from this pollution, and on its spatial and temporal variations.

Marine pollution by plastics has been shown to be damaging to marine mammals, birds and reptiles. This is due to entanglement in packaging bands, synthetic ropes and lines, or drift nets; or by the ingestion of small items of plastics debris. More research is needed to quantify the extent of the problems.

Wider use of degradable plastics will not solve the problems of plastics pollution. Their lifetimes are relatively long and unpredictable, and they are not generally acceptable for recycling.

Marine plastics pollution may be alleviated by the judicious application of both economic incentives and legislation, designed to decrease their use, to increase the rate of recycling, and to restrict uncontrolled discards.     

Control Criteria and Activities in Dumping Management in Italy

In Italy, two different types of wastes can be dumped in the seas: industrial wastes and dredged material. There are no cases of sludges from urban treatment plants being discharged into the sea.

The sea dumping of harbour dredging sludges is a long standing practice, while the disposal of industrial wastes dates back to 1965.

Two specific laws regulate these two activities, although they do not establish quality standards for the receiving sea environment. Careful evaluation must be made, case by case, of possible effects of discharge with regard to physico-chemical characteristics of materials, to general oceanological characteristics of the dumpsite and to the uses to which such a dumpsite is designated.

The analysis of different cases of industrial waste dumping, carried out at the pre-operational level and during discharge, revealed some potential for negative long-term effects on the sea environment. This, as well as the increasing public sensitivity to environmental problems, led the management agencies in Italy to take several measures aimed to stop all forms of sea dumping of industrial wastes and to revise the general criteria in issuing permits for the discharge of dredged material.     

The Role of Suspended Matter in Assessing the Assimilative Capacity Case Study of Two Estuaries in the Adriatic Sea

Suspended particulate matter has been studied in two Adriatic river mouths to assess its role as a transport vehicle for waste disposal into the Adriatic sea.

The larger of the two, the Adige River (northwestern Adriatic coast, Italy), carries large quantities of solids and builds up a prodelta. the Krka River (eastern Adriatic coast, Croatia, Yugoslavia) is a typical karst river, and carries small quantities of suspended matter, since it drains carbonate terrains.

The resulting disposal of contaminants into the Adriatic sea is largely governed by the adsorption/desorption processes occurring in the estuarine mixing region. Surface adsorption properties, the specific surface area, and the nature and reactivity of the organic film coating determine the partitioning of pollutants between the dissolved and particulate state.

The observations reported point to the key role of particulates in transport of pollutants from land to sea. the concept of the assimilative capacity of the estuarine area requires detailed scientific knowledge on the geochemical behaviour of particulates.

In the Adige River mouth, lead, chromium, zinc, and nickel are accumulated in the prodelta sediments, and thus the loading of the sea with these metals is diminished, whereas in the Krka River estuary, desorption and mobilization of some trace metals occurs.     

A Review of Waste Tyre Utilisation in the Marine Environment

Waste tyres pose a major disposal problem on land creating a fire hazard and, in warmer climates, providing breeding pools for mosquitoes. the void space in tyres makes them unsuitable for land burial. Schemes to use shredded tyres for road bases and asphalt filler are being pursued in the USA. Tyre combustion for electricity production is being investigated in the UK.

The widespread availability and durability of tyres has led to their use in the marine environment for breakwaters/coastal defence structures and as artificial reefs for promoting fisheries.

Tyres have a low density and have been used in floating breakwaters. Schemes have been proposed to protect and strengthen shorelines with tyre structures.

The void space in tyres facilitates the construction of artificial reefs to attract fish. the most intensive use is in the south west Pacific and Australia. Tyre surfaces are colonised by algae and a wide range of faunal species, including corals and shellfish. the wide acceptance of tyres as a suitable reef construction material appears to be based largely on these observations. Experience of initial poor deployment practices in the USA led to tyres washing ashore after storms and resulted in the banning or restriction of their use in coastal states of the USA. A review of the scientific literature has yielded limited information on the environmental impact of tyres and in particular the leaching of heavy metals and organic compounds from tyres into sea water.

Preliminary results of tyre dust/sea water leaching studies are presented. These identify zinc as the major leachate (totalling 10mg/tyre after 3 months). Diluted leachates have not shown significant effects of the growth of the phytoplankton Phaeodactylum and Isocrysis.

Further work to characterise the sea water leaching of tyre compounds is recommended.     

Book Review

B. J. Finlayson-Pitts and James N. Pitts, Upper and Lower Atmosphere, Published By Academic Press, 1999, 969 Pp, Catalog Card Number 99-63218, International Standard Book Number 0-12-257060-X.

P. Warneck, Chemistry of the Natural Atmosphere, Second Edition, published by Academic Press, 925 pp, International Geophysics Series, Volume 71, Catalog Card Number: 99-64620, International Standard Book Number 0-12-735632-0.     

Assessment of the Water Quality of the River Arno in the Area of Florence, Italy

The quality of the waters collected from R. Arno was examined in the period September 1988 to December 1989. A first campaign in September/October 1988, during a period of low water, gives a general picture of pollution conditions along the river from the source to the mouth. the river appears to be heavily polluted immediately downstream of Florence and in the area of the textile industry.

In the second campaign, through the whole year 1989, particular attention has been given to the Florence area; the most significant results, compared with those from a previous investigation carried out in 1971, show only a small reduction of the pollution load, due to the shortage and inadequacy of wastewater depuration. Some considerations are reported on pollution drop with full spate.     

Phosphorus in Sediments of Lake Edku, Egypt. The Influence of Chemical and Grain Size Parameters

Lake Edku is one of the Nile Delta shallow brackish water coastal lagoons with communications with the southeastern Mediterranean.

Sediment samples were recovered from the top 10 cm of the lake bottom to study principally their total, inorganic and organic phosphorus. Related sediment parameters such as particle size, organic carbon, carbonate and iron contents were also studied in detail.

It is shown that the lake sediments are generally a sand-silt-clay mud enriched with carbonate (11.4-42%), organic carbon (0.9-11.4%) and iron (1.6-5.6%).

The total phosphorus content in these sediments is 503-1329 μg/g, inorganic phosphorus, 468-954 μg/g and organic phosphorus, 35-526 μg/g.     

The Chemical Composition and Flow of the River Lea, Spain

Weekly measurements of chemical composition were made at four sampling sites on the Lea River (Spain) between July 1985 and August 1986. at two stations there were gauging-weirs for stream discharge monitoring. Conductivity, pH, alkalinity, silicon, calcium, magnesium, sodium, potassium, ammonia, nitrate, sulphate, chloride, reactive phosphate, and total phosphate, were recorded in each site.

Results were analysed using multiple regression techniques to study the relationship between flow and chemical components.

Conductivity, alkalinity, calcium, magnesium and sulphate were strongly related to flow, decreasing in concentration with increased flow. Ammonia, potassium, reactive phosphate and total phosphate varied most widely, with peaks at times of heavy rainfall. Nitrate increased at times of high discharge, with little variation between sampling points. Silicon decreased in summer and autumn in the lower catchment area whilst chloride and sodium were higher in the lower catchment of the River Lea.     

Determination of Phthalate Esters in Samples from the Marine Environment Using Gas Chromatography Mass Spectrometry

Phthalate esters have been extracted from water, sediment and biota samples using a single solvent system, dichloromethane, and clean up by alumina column chromato-graphy. Analysis for dimethyl, diethyl, di-iso-butyl, di-n-butyl, di-n-heptyl, di-(2-ethylhexyl) and di-n-nonyl phthalates was carried out by gas chromatography and mass spectrometry. Phthalate esters were quantified using multiple ion detection, focussed on m/z 163 and m/z 149.

The procedure was tested on samples of water, sediment, bivalves and fish from the estuary of the River Crouch. The method gave satisfactory sensitivity for the determination of phthalate ester levels above the commonly found blank values of 1 to 20 nanograms per gram of solid or litre of water.

Comparative samples of fish from the heavily industrialised Tees Bay area did not show greatly elevated levels of phthalate esters.     

Application of High-Volume Fly Ash Concrete to Marine Structures

A new material with high content of fly ash named 'Ashcrete' has been developed. to examine the applicability of Ashcrete to marine structures, strength characteristics, resistance to sea water attack, and safety in the marine environment have been studied. the following results have been obtained:

1) the strength characteristics of high-volume fly ash concrete depend upon the type and proportions of chemical activators as well as curing conditions.

2) Ashcrete using sodium chloride (NaCI) as a chemical activator shows high initial strength and good strength development with age.

3) Ashcrete containing NaCI activator shows good resistance to sea water from the viewpoint of its strength characteristics, volume changes and microstructurcs.

4) Since 1980 many types of large-scale artificial reefs made of Ashcrete have been installed in the sea. As a result of long-term studies and underwater observations, the Japanese Government has demonstrated the durability of the material, safety in the marine environment and attractiveness to fish.

5) It is therefore proposed that Ashcrete might be used in constructing large-scale sea mounts in deep water for the purpose of generating upwelling.     

Stability of a Coal Waste Artificial Reef

The feasibility of using U.K. coal-fired power station waste materials for artificial reef production is being examined. in June, 1989, an experimental artificial reef was constructed in Poole Bay, off the central south coast of the U.K., using three different mixtures of pulverised fuel ash (PFA), flue gas desulphurisation (FGD) gypsum and slurry, stabilized with cement and formed into blocks. Fifty tonnes of 40 × 20 × 20 cm blocks were formed into eight conical reef units replicating three different PFA/gypsum mixtures and one concrete control. the reef structure is 10m below chart datum on a flat sandy sea-bed.

Combustion of coal concentrates the heavy metal content in the resultant ash. the purpose of stabilization of the ash as blocks is twofold: to immobilize heavy metals (or other components) and to provide hard substratum for the attachment of organisms. to examine the effectiveness of this stabilization and hence the environmental compatibility of the block materials, heavy metal (Cd, Cr, Cu, Pb, Mn, Ni, Zn) content of the blocks has been monitored routinely over two years, to determine leaching rates. Sectional profiles indicate partial replacement of calcium content by magnesium. Associated with this there has also been some redistribution of heavy metals. Only in the case of cadmium has there been a detectable loss from the surface of blocks. Chromium and manganese concentrations appear to have increased. the metal content of the reef epibiota (including ascidians, Ascidia mentula; hydroids, Halecium spp.; bryozoans, Bugula spp. and red algae) growing on the ash blocks has been compared to that of epibiota attached to the concrete controls and surrounding sea-bed. to date no evidence of excess bioaccumulation of metals has been detected.

The physical integrity of the ash reef blocks has been maintained. There is evidence that the blocks are increasing in compressive strength.

An indication of the fishery enhancement potential of the experimental structure is given by the presence of eight commercially fished species (crustaceans and molluscs) including lobsters (Homarus gammarus).     

Factors Affecting the Conservation of Nutrients in Estuarine Waters of the River Tiber

The estuarine processes which can influence the release of nutrients of the River Tiber into the Tyrrhenian Sea have been studied. A conservative behaviour has been found for silicate in different hydrographic conditions.

For nitrogen, positive increments in respect of the dilution values were found in summer, due to regeneration processes; on the contrary a conservative behaviour was observed when seawater did not intrude into the river.

Dissolved phosphorus showed, in all the hydrographic conditions, a positive deviation in respect of the theoretical dilution values. This deviation has been attributed to regeneration processes which take place during the summer period. The chemical release of phosphate from particulate matter is predominant when the saline wedge is absent.     

Environmental Impact on Coastal Waters off Rio De Janeiro Due to Sewage Discharge via Submarine Outfall

A survey was made in an area of 28 km² around the outlest of Ipanema's submarine outfall in order to evaluate the impact of the raw domestic sewage effluent on coastal waters. Nutrient concentrations, dissolved oxygen, particulate matter and other physico-chemical parameters were measured monthly for 15 months. Copper and lead concentrations were also determined for two of the samplings.

The outfall has been in operation for 18 years, and the parameters measured within the observation area appear to be in steady state. From the observed radial concentration gradients within the survey area, a real extension of the steady state distribution of particulate matter and of sewage-derived nitrogen was estimated. the stationary cloud of particulate organic matter was about 150 km². From its total inventory and the discharge rate, a mean residence time of the particles in the sea of 56 days is estimated, prior to their being decomposed by bacterial action or settling to the bottom. for sewage derived N (as ammonia or nitrate), the steady state amount (above background) covers an area of about 60 km² and leads to a mean residence time of 5 ± 1 days in the ocean. Phosphorus is readily absorbed by the phytoplankton.

The presence of temperature gradients established by cold upwelling waters controls the dispersion of the sewage material and the rising of the sewage plume to the surface waters.     

Total and “Selective” Extraction Methods for Trace Metals in Marine Sediment Reference Samples (Mess-1, NBS 1646)

Trace metals (Cd, Cr, Cu, Mn, Pb and Zn) and Fe were analyzed in two sediment reference samples (NBS 1646, MESS-1) with AAS fitted with graphite furnace, using five different (three total and two selective) extraction procedures.

The comparison of the total digestion methods (hot strong acids) with reference materials gave good results for almost all of them, and the “teflon bomb” was preferred for its rapidity and ease of operation. Some non-referenced data on total and organic carbon, total nitrogen and minerals are given. The two selective leaching extractions (nitric and cold hydrochloric) were also compared with reference values.

The use of certified reference materials (CRM) for environmental chemistry is recommended, together with the determination of organic matter and fundamental mineralogical composition.     

Elemental Analysis of Water and Sediments by External Beam Pixe Part 3: Axios (Vardar) River, Greece

The Axios (Vardar) River originates from the south west part of Yugoslavia, transverses Greece, and discharges into the Thermaikos bay in the north Aegean Sea.

The proton induced X-ray emission (PIXE) method with external beam was used for the elemental analysis of water and sediment samples, while measurements of water temperature, dissolved oxygen content, conductivity, pH, and the water flow were made in situ. Water samples were also analysed for total phosphates, nitrates, chlorophyll, and BOD. The data collected for a 16-month period indicate that the Axios River is polluted as far as the metal content is concerned; its primary productivity is low and it is slightly enriched during its course into the Greek territory.     

Gypsum Waste Disposal: Land vs Sea or Recycling

The disposal of waste gypsum wallboard at landfill sites in British Columbia (B.C.), Canada, resulted in the generation of hydrogen sulphide gas and toxic leachates. Although some remedial measures were taken to reduce or eliminate problems resulting from past dumping practices, many landfill operators refused to accept new waste for fear of litigation over the pollution of nearby streams and rivers. with the availability of legitimate disposal sites greatly reduced, a serious waste management problem arose. the two most promising options for reducing the accumulating waste appeared to be recycling and ocean disposal.

Agricultural use of the waste for soil conditioning would account for only a small portion of the waste generated annually. Manufacturing plants were reluctant to accept waste gypsum with a high paper fibre content for fear it would lower the quality of the new wallboard product or interfere with the existing equipment and processes in the plants. the technology for economically removing and separating the paper from the used or substandard wallboard had yet to be developed.

The environmental implications of disposal at sea were assessed by a government advisory committee under the provisions of the Canadian Environmental Protection Act. Although results of a test dump in internal waters of B.C. were positive, the committee felt that valuable amenities of nearshore waters would only be assured by restricting dumping to a remote offshore location. an acceptable disposal method with minimal impact on the marine environment was eventually found with appropriate pretreatment of the waste and the use of remotely controlled bottom dump scows. Recent progress in the processing of waste wallboard to make it acceptable to the manufacturing industry should significantly reduce if not eliminate the need to dispose of gypsum wallboard wastes at sea.