Adverse Effects Of DBCP Biology Essay

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Banana is one of the most important staple crops in the world. As a result, many banana companies have search for new ways to increase production while obtaining a greater profit. This corporative goal is not a new one; on the contrary, corporations have made use of substances such as pesticides in order to increase their economic gains. DBCP became the solution for many American companies that produced different agricultural and chemical products during the 70s. DBCP is the acronym for 1,2-dibobromo-3-cloroprane and its chemical formula is C3H5Br2Cl,. However, DBCP is known as Nemagon and Fumazone as well. DBCP was a dense yellow organic liquid employed in soil fumigation in order to attack nematode worms that were harming banana trees and other agricultural products. Nemagon was also a Volatile Organic Chemical (VOC) because it vaporized at a relative low temperature. Appendix A illustrates the chemical and physical properties of Nemagon. This chemical was produced first by Dow Chemical Company and Shell Chemical Company and then, many other companies started to produce it. Extensive use of DBCP harmed population and contaminated underground water in several areas in California, Nicaragua and Costa Rica which led to the propagation of the chemical from soil as well. In this paper, I will analyze the scientific data behind DBCP.

Most of the evidence related with adverse effects of DBCP comes from animal studies and occupational exposure information. I will refer to animal data because human testing data is inexistent due to the ethical issues related to testing. The majority studies make use of rats and rabbits because they are equally or more sensitive than humans; thus it is assumed that animal studies reflect similar effects of Nemagon in humans. One of first discoveries about Nemagon was made by Kodama and Dunlap in 1956. They found out that absorption of this chemical by inhalation depended on the length of exposure and concentration. By testing rats, they calculated the lethal concentration (LC50) of this chemical in the air. In the same way, Torkelson (1961), Renik and Sprinchan (1975) and Reed (1987) determined that DBCP generate eye irritation, depression and behavioral changes after testing rats. In 1980, Reznik discovered that rodents exposed to Nemagon experienced high levels of toxicity in the respiratory tract. In 1984 Wong determined that Fumazon caused heart problems. Moreover, Saegusa reported damage in the duodenum and bone marrow of rats in 1986-87. He also found out renal lesions, changes in kidney weight and tubular necrosis in rats exposed to DBCP. Kaplanski, in 1991, concluded that Nemagon changes the weight of the suprarenal glandule, liver and spleen. As we can see above, diverse scientists concluded different effects of DBCP. Despite of this, the most important discover made by many of them was related to reproductive difficulties. DBCP increases testicular damage, male infertility, and changes in sperm motility. It also decreases the ability to impregnate females, the number of spermatozoid and reduces testosterone production. Moreover, it induces to changes in weight of seminal vesicle and epididymis.

After several in vitro tests in eukaryotic and prokaryotic cells, in vivo animal experiments and revision of workers health status, DBCP became considered a mutagen [1] and clastogen [2] as well. Some scientists concluded mutagenic outcomes after carrying out tests with salmonella and DBCP together. Additionally, genetic effects were found in mammalian germ cells. For example, Lee and Suzuki determined unplanned DNA synthesis in mice after exposure with Fumazon in 1979. Furthermore, Teramoto reported lethal mutations in rats after high doses in 1980. Between 1977 and 1978, Hazleton Laboratory under contract with Dow Chemical Company made a study on reproductive toxicity and cancer during 32 weeks with 60 female rats and 60 male rats which were fed with DBCP. Results said that DBCP was a danger in high doses. However, the problem with this report was that they gave information only for high doses but not for the two lower dose groups. Shell Chemical Company also tested animals but results either were never shown to the public or exclude information.

After analyzing all the previous experiments and conclusions, the Office of Environmental Health Hazard Assessment (OEHHA) determined the no observed adverse effect level (NOAEL). This level was especially based on the studies made by Rakhmatullaev (1971), Reed (1987) and Rao (1983) because they reported their information adequately and provided data with lowest chronic effect. NOAEL was adjusted based on length of exposure and human defaults factors such as weight (70kg or 154 pounds.)

Thresholds were only determined after DBCP was banned in United States in 1979. The United States Environmental Protection Agency (EPA) determined the LC50, and the lowest observed adverse effect level (LOAEL.) In addition, it was established the Reference Concentration for Chronic Inhalation Exposure (RfC) which is 2E-4 mg/cu.m and the Occupational Safety and Health Administration's Permissible Exposure Limit (OSHA PEL) expressed as a time-weight average. OSHA PEL refers to the acceptable level of exposure for a 40-h/week worker. Appendix B illustrates health data from inhalation exposure released in 1999.

Occupational exposure has demonstrated the negative effects of Fumazon in workers from both chemical companies and banana companies. Their primary pathways of exposure of DBCP were inhalation and dermal contact. However, general population has been harmed through the contamination of water (oral/ingestion) and the contact with contaminated soil as well. In fact, extensive used of DBCP in crops have contaminated underground aquifers in areas such as Sacramento Valley, California. Studies have revealed that the persistency of Nemagon in groundwater depends on pH and temperature. Additionally, animal studies have shown that Nemagon can be metabolized by liver, kidney and gastrointestinal, thus, ingestion of DBCP is highly harmful. As a result, EPA determined the Maximum Contaminant Level (MCL) in water even though no levels can be considered completely safe with cancer-causing chemicals. After doing a cost-benefit analysis, EPA decided that MCL corresponds to 200 parts per trillion (ppt.) Based on the DBCP Consumer Fact Sheet from the Department of Health services in California, only one person of 10 000 people might have cancer if all of them drink two liters of water contaminated with Nemagon at 0.2ppb for 70 years.

According to the United States Occupational Safety and Health Administration (OSHA 1978), around 50 workers at Dow Chemical Company were either oligospermic [3] or azoospermic [4] . It was reported that there was about 1ppm of the chemical in the air of the facility which corresponds to a relatively low quantity of the chemical. Thus, Dow workers' reproductive problems are also attributed to their physical contact with the chemical (dermal exposure.) In 1991, Thrupp investigated the adverse consequences of applying DBCP on Costa Rican crops where Standard Fruit Company workers were employed. He concluded that most of the workers where sterile and were either oligospermic or azoospermic due to the lack of protection and direct contact with Nemagon.

Goldsmith and Potashnik (1984) focused their research on genetic toxicity. They demonstrated that a higher rate of females was born when parents were previously exposed to DBCP. Subsequently, R. Kapp proved genetic mutations after studying dermal and inhalation exposure of workers at Dow Company in Magnolia. In terms of carcinogenicity, Appendix C illustrates animal, occupational and contaminated water evidence of DBCP to be a carcinogen. However, there is no real demonstration of DBCP to be a carcinogenic in humans due to the fact that cancer symptoms may not be immediately noticeable and cancer can be caused by multiple factors.

Despite of the results of the studies mentioned above, most of the available information to consumers about the dangers of DBCP refers only to reproductive difficulties and increased cancer risk. This means that neither national nor international institutions recognize others risk of DBCP. In fact, the International Agency for Research on Cancer (IARC) and EPA classify Nemagon as a possible human carcinogen. Additionally, the National Toxicology Program (NTP) categorizes the carcinogenicity of DBCP as reasonably anticipated.

Today, Fumazon is banned in United States, Costa Rica and Nicaragua but its effects are still alive. It seems that the fight against this chemical is a class struggle. First, this is because many of the producers of DBCP kept selling it even though after banned for profit purposes, thus, contamination increased. Second, chemical companies and banana companies such as Dole and Chiquita fail to admit their environmental and social responsibilities. In addition, workers (especially Latin American workers) have had to face the health effects of the highly toxic chemical Nemagon. Despite the fact that they have suit companies to get some kind of compensation, those companies have continued evading their liability. Furthermore, most lawsuits have eventually been dismissed as a result of frauds made by workers' lawyers. Finally, neither private nor public institutions have been able to control the consequences created by chemical and bananas companies and make justice. In fact, the negligence of Centro American governments can be seen with the banned dates. While Nemagon was banned in United States in 1977, Costa Rica did it in 1979 and Nicaragua took 14 years more than Costa Rica to do it. Nevertheless many people already died and others renounced to take any kind of action, a large number of victims are still waiting for legal actions to work.


Physical and Chemical Properties of DBCP


Health Data from Inhalation Exposure of 1,2-Dibromo-3-Chloropropane

The health and regulatory values cited in this factsheet were obtained in December 1999.

a Health numbers are toxicological numbers from animal testing or risk assessment values developed by EPA.

b Regulatory numbers are values that have been incorporated in Government regulations, while advisory numbers are non-regulatory values provided by the Government or other groups as advice.  OSHA numbers are regulatory.

c The LOAEL and NOAEL are from the critical study used as the basis for the EPA RfC.


Carcinogenicity Evidence

Type of Report

Entity or Person


Water Contamination

California Department of Health - (Jackson 1982)

Association between DBCP in groundwater and incidence of leukemia and cancer in stomach.

Water Contamination

Environmental Health Associates (EHA 1986)

No significant association between DBCP, cancer and groundwater. But DBCP increases cancer risk.

Occupational Exposure

Wong 1984

Cohort study showed no significant cancer risk in workers exposed to nemagon.

Occupational Exposure

Herarn Study 1984

Cohort study concluded no significant respiratory cancer increase with DBCP.

Animal Study

OEHHA 1988

Estimation of human carcinogenic potency based on cell carcinomas in female mice.