In those countries where pesticide regulatory or control systems have not yet been implemented, a request for registration of a pesticide product by a manu-facturer should be accompanied
Trang 1S u m m a r y
Milton D Taylor and Stephen J Klaine
G O V E R N M E N TA L P O L I C I E S
Existing environmental legislation, regulations, and standards concerning the coastal and marine environments must be enforced However, there is a need in some countries to strengthen and broaden environmental protection either through creation of enforcement agencies where absent or by developing and expanding the legal framework for protecting coastal and marine environments The legal framework for protecting the marine environment must be further developed on both the international level and within the legal context of individual countries Comprehensive, enforceable laws dealing with pollution of surface and ground waters by pesticides and other pollutants are needed Many of the less developed countries of the tropics have modeled their environmental institutions and laws after those of more industrialized and developed nations; however, those countries still in the process of establishing or revising their environmental protections should learn from the mistakes of others and seek to improve the basic model to fit local conditions, environmental, cultural, and political As authorities responsible for regulatory control of pesticides become adequately conversant with control systems already in effect in other countries, they will be able to more effectively streamline the guidelines and standards currently in effect in various countries to ensure the future safe use of pesticides
In those countries where pesticide regulatory or control systems have not yet been implemented, a request for registration of a pesticide product by a manu-facturer should be accompanied by a comprehensive data set collected by the manufacturer’s research group, which would include a wide range of toxicity data, persistence data, environmental fate and effects data (all of which should be collected under local conditions if economically feasible, or under suitable surrogate conditions, i.e a similar tropical climate) and details of the nature and sensitivity
of analytical techniques used to collect the data Pesticides should also be re-registered periodically with a review of current data on the pesticide and a requirement that the registering company submit residue data collected under local conditions Currently, in most countries once registration is given, a pesticide can be marketed forever until restricted or banned by a government agency because
Trang 2of an awakening recognition of its hazards No pesticide product, or active ingre-dient, should be registered or reregistered without limits placed on its use Pesticide products should be registered for a specific purpose on a particular crop with guidelines to describe the proper manner of application Failure to do this can become a recipe for disaster in countries with poorly educated farmers if they use
a product indiscriminately Choosing a pesticide for a particular purpose is a highly skilled task and should not be performed by the uninformed Thus, all stages of a pesticide’s life cycle, e.g import licenses, registration, storage, packing, labeling, transport, retailing, aerial spraying, and applicator training, must be addressed and regulated
Many tropical countries need to develop programs to exercise control over residue levels present in food at the time it is offered for sale Awareness among the general public about pesticide residues and their potential for contaminating the environment is also lacking Because it is impossible to test all farm produce, a monitoring approach requires the establishment of regulations concerning maximum permissible residue limits that must not be exceeded in marketed food Exceeding these limits must lead to legal action against the offending farmer or trader and destruction of the condemned produce There is neither the political will nor sufficient money in most national budgets to police all local markets and imported products Further, this approach would be meaningless unless the govern-ments concerned establish well-equipped laboratories of international caliber and reputation and staff them with teams of trustworthy analysts and inspectors The capability of many tropical countries’ governmental agencies to generate and analyze data on pesticide contamination in food, feedstuffs, and the environment
is limited by a lack of sophisticated instrumentation, the requisite equipment main-tenance funding and staff, and adequate manpower with the expertise needed to run such nationwide programs Funding for such programs, initiatives, and infra-structure is not available locally; if it is to be done, then the international community, through the United Nations, will have to step forward and provide both leadership and resources
Environmental impact assessments of proposed large-scale projects must be given due consideration Government funds for environmental impact studies of pesticides and other toxicants are limited, with many government’s highest priority geared toward increasing production in the agriculture and fisheries sectors Unfortunately, support from international sources is often limited or non-continuing
in nature and, therefore, pesticide residue data are few and far between Often, a lack of coordination and integration of government effort and the funding required for implementation is lacking, especially in the area of environmental management Some countries, e.g Vietnam and some parts of the Commonwealth Carribean, are in the initial stages of tourism development For them, the challenge is to maintain the pristine condition of the ecosystems that attracted the development They have a unique opportunity, in the planning, design, and construction phases,
to develop chemical management and land use strategies to prevent or minimize ecosystem deterioration Pristine coastal ecosystems can be quickly spoiled by
Trang 3untreated or inadequately treated sewage and wastewater discharges from the rapid expansion of tourism infrastructure, e.g airports, hotels, marinas, and restaurants, encouraged by increased tourist interest in previously undiscovered areas If legislation, policies, and regulations are already in place, regions can profit from becoming the ‘new’ and ‘in’ destination without harming the very asset that had attracted visitors initially
The success of pest and pesticide management in tropical countries is directly related to the state of environmental awakening in the general public and a general appreciation for environmental problems developed among policy and decision makers in government and industry and the public Many countries have established education and training programs to promote industry and public awareness of environmental problems and concerns and sound environmental practices Citizen education and outreach to pesticide users may also reduce mismanagement and misuse of these chemicals Other programs are designed to educate tropical countries’ farmers and agricultural workers about IPM techniques and management practices that minimize excessive use of pesticides and chemical fertilizers Similar programs should be adopted by other tropical countries with an effort to learn from others’ successes and mistakes The use of the farmer field school concept for teaching IPM to rice farmers in several of the countries has achieved notable success in most locations where it has been implemented Its adoption for other crops could significantly reduce pollution from chemical pesticides and fertilizers
In the tropics lindane, endosulfan, chlordane, and BHC are the remaining OCs
in limited to widespread agricultural use However, they are of primary concern with respect to the aquatic environment Lindane and endosulfan are in the most widespread use and have proven highly toxic to aquatic life forms While these compounds may be restricted or banned by more countries in the near future, the implementation of buffer zones in sensitive areas may help to minimize their entry into waterways In areas where such an approach may not be practical, alternative pesticides with minimal toxic effects to aquatic organisms, while still maintaining field efficacy, should replace those currently being used There seems to be a general consensus that the pesticide industry must energetically develop new pesticide classes and pesticide varieties with high performance, novel modes of action, low toxicity, and low residues to replace the older pesticide varieties that can cause serious pollution of agricultural ecosystems and leave high residue levels on farm produce Concurrently, pesticide manufacturing countries must also pursue research, development, and production of biological pesticides, alternative pest control measures including biocontrol, natural predators and pathogens, pest resistant cultivars, and genetic engineering of crops and pursue subsidized use of biological and ‘safe’ chemical pesticides This policy would force product structures to tend toward becoming more ecologically friendly
Finally, it is essential that laboratories that produce data on pesticide interactions with environmental compartments and residues be required to have quality assurance (QA) and control (QC) procedures that meet the standard criteria of ISO-25 Good laboratory practices (GLP) and laboratory standard operating
Trang 4procedures (SOPs) are necessary for reliable and dependable analytical systems and include standardization of facilities for analysis The reliability of data gene-rated by these laboratories must be assured and internationally accepted
R E S E A R C H N E E D S
More extensive studies are needed in many tropical countries on the extent and effect of pesticide pollution with particular emphasis on residues in marine, coastal, and estuarine environments Although attempts have been made to determine residues in the marine environment and a large amount of data is available, a planned, systematic survey is lacking Such a study would help in arriving at residue distribution among different compartments of marine ecosystems and elucidating the interactions between compartments Sufficient data is still needed in many countries to properly develop and manage the marine environment These studies would measure the level of contaminants, study contaminant accumulation that might lead to biological impacts, and record baseline data on the distribution of flora and fauna on beaches, in coastal lagoons and estuaries, and in other near-shore ecosystems Additionally, documentation and evaluation of pesticide use in aquaculture and fishing activities is necessary to provide baseline information for managing this agricultural sector Research is needed to determine the environ-mental consequences of chemical use in inland and coastal aquaculture and this research should examine pesticide impacts on non-target organisms, chemical fate and movement, effects, accumulation, degradation, and pest resistance development
There is also a need for studies to assess the impact of inland drainage and land-based pollution sources on coastal lands and waters Such studies would provide a scientific basis for legislative provisions to establish appropriate abatement and control measures Additional studies are needed to characterize industrial effluents and to identify the most hazardous pollutants that might require imple-mentation of immediate control measures Also an estimate of the input rate of pollutants into estuaries and coastal zones from land-based sources, the distribution pathways of pollutants into estuarine and coastal waters, and long-term studies on the biological impact of pollution discharges into the coastal zone would be very useful
Although much can be learned from studies conducted in temperate countries, there is clearly a need to conduct similar studies to elucidate the movement and fate, distribution, behavior, and bioavailability of pesticides in tropical ecosystems
to assess the potential impacts of these chemicals in the tropics Supervised field trials must be arranged to supplement a manufacturer’s data and to ensure that local climatic and environmental factors are accounted for in registration delibera-tions Safety in the use of pesticides is a dynamic challenge and locally generated data must cover the formulations in use, use patterns, and cropping systems from the tropics Ecotoxicological aspects of pesticide use under a given ecological
Trang 5scenario are an essential requirement for safe use of pesticides Knowledge about the environmental movement and fate, distribution, and bioavailability of pesticides and the development of pest resistance under tropical conditions is essential for understanding the consequences of pesticide use and misuse on tropical aquatic ecosystems, developing environmental impact statements and risk assessments, making prudent pest management decisions, and improving aquatic, estuarine, and coastal management policies Also, special emphasis should be given to studies examining the potential impact on tropical aquatic ecosystems of repeated and continual low-level exposures to mixtures of pesticides
Contemporary pesticides, e.g ametryn, cadusafos, chlorothalonil, cypermethrin, propiconazole, quinclorac, and carbofuran among others, which have been found
in aquatic ecosystems should be regarded as priority substances for future studies
A major need will be the development of sensitive methods to monitor pesticide effects on ecosystems Criteria related to general water quality and specific criteria for tropical aquatic ecosystems must be developed The concept of acceptable risk levels should be assessed relative to protection of valuable tropical aquatic ecosystems It will be necessary to develop a ‘tropical’ definition of water quality, acceptable risk, and methods for environmental evaluation Studies to develop pesticide reduction strategies especially for the more toxic pesticides are greatly needed
The toxicity and effects of many of the currently used pesticides and their metabolites to aquatic organisms, especially invertebrates, need to be studied A database developed from such a study would greatly assist efforts to conduct risk assessments of pesticides A systematic study with well-defined short and long-range objectives would be of great value in evaluating and sustaining the health of the tropical marine environment
While agricultural activity is the greatest contributor to pesticide pollution of the environment, there is a significant environmental contribution from the waste discharges of pesticide manufacturers Characterization of these waste products
is important for understanding their effects on ecosystems
Considering the limitations of acute toxicity data, information on pesticide residue effects on ecosystems is essential to properly assess impacts To achieve this, micro- and mesocosm studies may serve as a bridge between simple LC50 data and comprehensive ecosystem assessments Ultimately field validation will be necessary to match predictions derived from laboratory, micro-, and mesocosm tests to observations of the responses of complex tropical ecosystems
There is clearly an increasing need to develop and adopt IPM strategies for other tropical crops besides rice and the few major crops for which the information
is available This would require extensive research in various approaches to pest control in the specific tropical agroecosystems, including the introduction of multi-pest resistant cultivars, biological control methods, natural predators and pathogens, and effective training of farmers in the implementation of IPM strategies and techniques
Trang 6E D U C AT I O N N E E D S A N D I N I T I AT I V E S
Education and training programs, including workshops, seminars, pilot demon-stration parcels with farmers, extension training projects, and public service announcement campaigns, should be established to educate the general public about the environment in general, environmental problems, chemical and non-chemical pollutants and contaminants, and sound environmental practices These nationwide campaigns are imperative and must include school children to provide continuity for the program Furthermore, agricultural management practices that minimize excessive use of pesticides and chemical fertilizers should be developed and instituted throughout the tropics There is a widespread need for developing and implementing training programs for pesticide handlers and applicators and their families A major concern for the continued success and expansion of IPM
in the tropics is the belief by farmers that pesticides are the only viable solution to their far ming problems For historical reasons, many tropical farmers’ understanding of the scientific basis for the use of pesticides is incomplete and their concept of environmental protection is minimal Because farmers directly use pesticides, it is very important to increase their knowledge of the reasons behind protecting the environment and minimizing pesticide use Moreover, it is also essential to conduct technical and environmental awareness training for policy-makers at different political levels in addition to training the technicians and workers involved in pesticide production and application
Application of pesticides in the field is the predominant cause for their conta-mination of the environment Thus, an extensive program of public education to fuel public awareness on the proper uses of pesticides needs to be instituted where lacking and continued, improved, and reinforced where in place to minimize the indiscriminate and irresponsible use of pesticides While countries readily accept the responsibility of promulgating relevant pesticide regulations, they must also assume the task of educating their people on safe pesticide use and establish an efficient means of supervising pesticide use to safeguard people’s health The side effects of pesticides caused by poor production and poor application techniques may include serious pollution and other environmental problems in addition to their toxic effects on wildlife and human beings Continuous use of single pesticides leads to rapid resistance development in pests and, ultimately, to failure of the pesticide from pest resistance Manufacturers and farmers seldom investigate the causes of such failures Farmers often blindly increase the concentration of the pesticide or its frequency of use, further inducing resistance by pests and polluting the environment A nationwide information dissemination and training program, especially for farmers and aquaculturists, on the development of resistance and the effects of pesticides in the environment can go a long way toward alleviating this problem
Finally, the training of more environmental scientists, engineers, and managers, both locally and overseas, should be instituted throughout the tropics with adequate long-term funding and support from the international community
Trang 7M O N I T O R I N G N E E D S
While the widespread use of pesticides continues, there is a need for extensive monitoring of their residues in the environment Thus, where absent, effective monitoring programs must be established to monitor estuarine and marine pesticide levels, oil pollution, industrial and sewage pollution, and to encourage research on pesticide residues and their effects on aquatic organisms Additionally, pollution monitoring of beaches and coastal waters should be instituted and bacteriological quality control of bathing waters should begin Such monitoring programs must be supported by the necessary regulatory capacities, coupled with effective enforcement mechanisms to prevent contamination levels from exceeding locally established limits as stipulated by the appropriate legislatures
Throughout these studies, the impact of pesticide residues contributed from agricultural activities could be discerned if river mouths of major rivers passing through the agricultural fields’ drainage areas were monitored As the capability
of monitoring contaminants is strengthened, the environmental and social costs
of inland and coastal aquaculture, rice fish culture, agriculture, and manufacturing can be assessed Then, pesticides and other contaminants can be evaluated not only for localized effects but in the context of nationwide risk assessments This will provide data for new legislative initiatives to protect the marine environment from unnecessary risks from pesticide use
P R O S P E C T S
Tropical agriculture, like that in other countries, faces certain common problems There is a continuous reduction in the amount of useful agricultural land due to growing cities, recreational areas, industrialization, and park preserves Further-more, every year valuable soils are lost to erosion from the deforestation that began more than 100 years ago but continues today An increasing population, which demands higher quantities and better qualities of agroproducts, and a need for expanded agricultural exports to contribute to national economic development pose a tremendous challenge to tropical agriculture It must produce more and better crops using less land and this necessarily implies an increase in productivity, achievable only through correct and timely application of science-based agricultural knowledge, including the prudent use of pesticides
Despite worldwide efforts to find substitutes for agrochemicals, world food production will depend on the use of these chemicals for the foreseeable future
To relieve projected food shortages, Africa and Latin America are expected to increase their use of agrochemicals Therefore, increased monitoring of pesticide residues will be necessary to preserve the environment and contribute to sustainable agriculture This will require both an investment in scientific, regulatory, and enforcement infrastructure and the periodic upgrading of the knowledge and skill levels of environmental and agricultural scientists More support for basic and
Trang 8applied research will be needed if enforcement of environmental regulations is to become easier so as to achieve the end result of better protection for the tropic’s unique and diverse environment
C O N C L U S I O N S A N D R E C O M M E N D AT I O N S
Measurements of OCs in marine waters from the Arabian Sea showed low residue levels Aldrin, HCHs, and DDTs were the most abundant and most commonly found pesticides in the Arabian Sea Concentrations of DDT in the zooplankton showed a decreasing gradient from the near-shore to offshore However, sediments from the Bay of Bengal contained an order of magnitude higher residues than sediments from the Arabian Sea This was attributed to residues carried by the major rivers, which primarily flow east through heavily agricultural lands located there Green mussels collected from the East Coast of the Indian Subcontinent had high levels of HCH while West Coast samples had high levels of DDT This pattern is indicative of the different pesticide usage patterns for agriculture (HCH) and public health purposes (DDT) It appears that, in general, pesticide residues are low in the Indian Subcontinent marine environment, possibly due to the impact
of semi-diurnal tides coupled with the influence of the biannual reversal of the direction of monsoon winds that ensures widespread dispersion of pollutants throughout the Arabian Sea, the Bay of Bengal, and the northern arms of the Indian Ocean
Assessment of the fisheries sector in Asia has identified resource depletion, environmental damage, poverty among fisherfolk, low productivity, and limited utilization of offshore waters by commercial fishermen as major problems for the industry Over-fishing and habitat degeneration has resulted in no substantial increase in fish capture in near-shore areas of some countries However, many countries expect an increment of increased fish production to come from aqua-culture, but aquaculture’s use of chemicals may result in excessive environmental costs
Monoculture-type agriculture for producing banana, coffee, sugarcane, rice, ornamentals, and fruits is one reason for the intense and predominant use of pesticides in the Caribbean, Central, and South America This method of farming depends heavily on agrochemical use, which has many negative consequences These include pest resistance development, soil deterioration, aquatic ecosystem degradation, the emergence and proliferation of secondary pests, adverse health effects on the general and agricultural labor populations, and various other environ-mental effects from the exposure of wildlife to pesticides residues
1 In general, few large-scale effects have been documented given the ubiquitous
OC pesticide residues in these tropical ecosystems One caveat to this is that endocrine effects have not been investigated
Trang 92 Toxicological investigations in these countries focus on the individual organism level and little attention has been paid to other organization levels including molecular, biochemical, population, community, and ecosystem levels
3 Pesticide residues in sediments can be hydrologically connected to upstream land management practices
4 International aid efforts must have education and outreach as integral com-ponents of their efforts
5 IPM, involving a combination of chemical, biological, and cultural methods
of pest control, has proven a realistic and viable means of decreasing the negative impacts of the excessive use of pesticides throughout the tropics
6 Farmer and farm worker education is critical to the successful implementation
of IPM programs
7 Education should not be confined to the agricultural community but should embrace all sectors of society including school children and political leaders
8 It is obvious that additional multi-nation monitoring programs are needed to document changes from the present pesticide residue levels New chemistries and co-operation between regional nations
9 Continued influx of resources for pesticide monitoring must come from both internal and international government agencies
10 The concept of sustainable resource management must be in the forefront of decision-making
11 Better cause and effect relationships between land use and the deterioration
of near coastal resources must be developed
12 It is important to consider the environmental problems associated with pesticide use in association with the related agricultural, economic, political, and public health issues
13 Best management strategies currently used in temperate climates must be successfully implemented and evaluated – with modification as needed – in tropical land use and development
A F E W F I N A L R E M A R K S
Both governmental and non-governmental institutions must work together with farmers, farmers’ associations, and other players in the agricultural and food marketing and distribution sectors to conduct research and facilitate technology transfers with a goal of more rational and sustainable agricultural practices The use of integrated pest management (IPM) programs and organic farming move-ments in a number of countries are excellent examples of positive movement toward sustainable agriculture
Effective schemes for minimizing some of the risks associated with the use of pesticides already exist in countries such as the USA and the European Community Agencies of the United Nations are extending cooperation, collaboration, and
Trang 10expert guidance to developing countries around the world in devising practical steps for the control of pesticides They are assisting in maximizing pesticides’ beneficial role while minimizing risks associated with undesirable levels of residues
in abiotic compartments, biota, food chains, and foodstuffs and reducing untoward effects on non-target organisms in the environment
Perceived personal benefits should not be the overriding factor in the decision
to apply pesticides because every time they are used, a certain risk is involved especially if the usage is not judicious People from many countries should begin
to reorient their concept of the environment so that it is not limited to the house, the yard, the place of work, and the immediate community but focuses on the national and global scale The increased productivity of countries’ resources must proceed hand-in-hand with the conservation and preservation of those resources for future generations The idea of sustainable development, natural capital, and the responsibility of the current generation to preserve its resources for the future should be ingrained in every citizen of the world