(Beyond Pesticides, June 20, 2011) In a study published this week in the journal Pediatrics, researchers report findings that link mothers’ exposure to organochlorine pesticides during pregnancy with infants’ sizes at birth. The trend shows that the more mothers are exposed to the pesticides during pregnancy, the higher the chances are for reduced birth weight and length of their newborns. Comprising a total of 494 women and infants in Valencia, Spain from the years 2003-2006, the study evaluates umbilical cord blood for residues of four pesticides or pesticide degradates: DDT, DDE, hexachlorobenzene (HCB), and beta-hexachlorocyclohexane. The results show that a 10-fold increase in pesticide concentrations in the blood corresponds to a reduction in birth weight of 2-4 ounces. Additional results are correlated to specific pesticides. Higher concentrations of DDT results in a reduction in head circumference of 0.26cm, which the researchers call a “significant decrease.” Additionally, a decrease of 0.39cm in birth length is correlated with each 10-fold increase in concentration of HCB. The researchers note several concerns related to the findings, aside from the results themselves. Since people are exposed to a wide variety of chemicals in general throughout their everyday lives, higher pesticide exposure could betray higher exposure […]

(Beyond Pesticides, May 2, 2011) Nations gathering in Geneva last week finally agreed to add endosulfan, an antiquated persistent insecticide, to the Stockholm Convention’s list of banned substances. The decision follows recommendations from the December 2009 Stockholm Convention Persistent Organic Pollutants Review Committee (POPRC), which call for urgent “global action” to address health and environmental impacts of the toxic pesticide. Scientific experts at the POPRC concluded that endosulfan is likely to cause significant adverse human health and environmental effects as a result of the chemical’s medium- and long-range transport on a global scale and subsequent accumulation in nearly all environmental media. Environmental health and justice organizations from around the world who have been working toward a ban welcomed the decision. Endosulfan is an organochlorine insecticide that was first registered for use in the U.S. in the 1950s. It is an endocrine disruptor and exposure in male children may delay sexual maturity and interfere with sex hormone synthesis. Male school children exposed to the highly toxic insecticide endosulfan showed delayed sexual maturity compared with similar children who were not exposed. Endosulfan also appears to interfere with sex hormone synthesis in males aged 10-19 years in a community of cashew plantations in […]

(Beyond Pesticides, April 28, 2011) In recognition of the 3rd annual Save the Frogs Day, a “Save the Frogs/Ban Atrazine Rally” will be held tomorrow, Friday, April 29th in Washington, DC. The rally will take place at the steps of the U.S. Environmental Protection Agency (1200 Pennsylvania Ave, NW), and is intended to raise awareness of the rapid disappearance of frog species worldwide, and bring attention to the harmful effects of the endocrine disrupting herbicide atrazine. Amphibian populations worldwide have been declining at unprecedented rates, and nearly one-third of the world’s amphibian species are threatened with extinction. Up to 200 species have completely disappeared in recent years. Amphibians are faced with an onslaught of environmental problems, including climate change, infectious diseases, habitat loss, invasive species, and over-harvesting for the pet and food trades. Numerous studies have definitively linked pesticide use with significant effects on amphibians. Pesticides can cause abnormalities, diseases, injury and death in these frogs and other amphibians. Because amphibians breathe through their permeable skin, they are especially vulnerable to chemical contamination. Frog eggs float exposed on the water surface, where pesticides tend to concentrate, and hatched larvae live solely in aquatic environments for five to seven months before […]

(Beyond Pesticides, March 28 2011) Researchers found that exposure to organochlorine pesticides significantly alters semen quality in young men from southeast Spain. The study found 18 pesticides in the blood of the study participants, including some banned in Spain, such as DDT, and others legal in in the country, such as the fungicide vinclozolin. The analysis was conducted by Clemente Aguilar from the Medical Research Laboratory of the University Hospital San Cecilio, Granada, Spain, and coordinated by Marieta Fernández, Marina Lacasaña and Nicolás Olea (University of Granada), basing on a sample of 280 volunteer students aged 18-23 years from the University of Almería, Spain. All the study participants had at least one pesticide in considerable concentrations. The average number of pesticides detected in the blood tests was 11. Southeast Spain is a region where two out of ten young men have poor sperm density. Even though exposure to some organochlorines proved to increase total spermatic number and total sperm motility levels, other pesticides were highly associated with a reduction in sperm levels. This might be due to the fact that some of these pesticides are considered to be estrogenic endocrine disruptors. Endocrine disruptors are substances that interfere with natural hormones […]

(Beyond Pesticides, January, 19, 2011) A new study finds for the first time that the bodies of virtually all U.S. pregnant women, and possibly their unborn children, carry multiple chemicals, including some used in common products such as non-stick cookware, processed foods and personal care products. Median levels of the controversial chemical triclosan are found to be higher in pregnant women compared with nonpregnant women. This new data highlights the urgency needed to remove toxic chemicals like triclosan from consumer products. While the Centers for Disease Control (CDC) has published previous reports on chemical levels in the general population, this is the first study to look at a broad range of chemicals specifically in pregnant women. Entitled, “Environmental Chemicals in Pregnant Women in the US: NHANES 2003-2004,” the study analyzed biomonitoring data from the National Health and Nutritional Examination Survey (NHANES) to characterize both individual and multiple chemical exposures in U.S. pregnant women. Researchers analyzed the data for 163 chemicals and detected about three-quarters of them at varying levels in some or all of the women. They found almost all — 99 to 100 percent — of the pregnant women carry polychlorinated biphenyls (PCBs), organochlorine pesticides, perfluorinated compounds, phenols such […]

(Beyond Pesticides, December 20, 2010) A new study examines the residue levels of the organophosphate insecticide chlorpyrifos in Colombian potatoes, finding that residual levels of the pesticide are still present even after being cooked. According to researchers, the pesticide has a tendency to build up in the raw potatoes, but once they were cooked, the levels dropped by 14%, leaving a fraction of the allowable levels of chlorpyrifos in the potato, under European Union (EU) daily intake limits. While it may be true that there are relatively low residual levels of the pesticide found in the potato once it has been cooked, many adocates are concerned about the remaining residues. The study, entitled “Pesticide Uptake in Potatoes: Model and Field Experiments,” was published in the journal Environmental Science and Technology. The fact that there remains some residual chlorpyrifos in the cooked potatoes is a concern because studies show that even at low doses, in utero exposure can cause changes in brain function and altered thyroid levels that last into adulthood. Young children are particularly susceptible to the effects of exposure. Because children’s diets often include significant quantities of potatoes, this is particularly alarming in light of a recent study that […]

(Beyond Pesticides, December 8, 2010) A new study finds that oral contraceptives are not the main culprit in estrogenic pollution of U.S. rivers and drinking water. Instead, the contribution of contraceptives is quite small compared to other human, industrial and agricultural sources, including pesticides. Recent observed feminization of aquatic animals has raised concerns about estrogenic compounds in water supplies and the potential for these chemicals to reach drinking water. Public perception frequently attributes this feminization to oral contraceptives (OCs) in wastewater and raises concerns that exposure to OCs in drinking water may contribute to the recent rise in human reproductive problems. Studies have suggested that long-term exposure to low levels of estrogens in water may adversely affect human health. This new information eases concerns that contraceptives are a major factor contributing to feminized fish and frogs. This study, “Are Oral Contraceptives a Significant Contributor to the Estrogenicity of Drinking Water?” reviews the literature regarding various sources of estrogens, in surface, source and drinking water, to determine whether OCs were the source of estrogen in surface waters, with an emphasis on the active molecule that comes from OCs. The authors find that industrial and agricultural sources not only discharge estrogens, but […]

(Beyond Pesticides, October 5, 2010) A new report by the Breast Cancer Fund, a national organization working to eliminate the environmental causes of breast cancer, presents a summary of the scientific data on the environmental causes of the disease. The report catalogs the growing evidence linking breast cancer to, among other factors: synthetic hormones in pharmaceuticals, cosmetics and meat; pesticides in food; solvents in household cleaning products; BPA in food containers; flame retardants in furniture; and radiation from medical treatments. The report also highlights impacts on the most vulnerable populations (including infants, pregnant women, African-American women and workers), and outlines the policy initiatives required to develop a national breast cancer prevention plan. The report, State of the Evidence: The Connection Between Breast Cancer and the Environment, is the sixth edition published by the Breast Cancer Fund. “With each new edition of the report, the growing scientific evidence compels us to act to prevent breast cancer,” said Jeanne Rizzo, RN, president of the Breast Cancer Fund. “This Breast Cancer Awareness Month, our message is clear: we must move beyond awareness to prevention.” The report states that a woman’s lifetime risk of breast cancer is 1 in 8””representing a dramatic increase since […]

(Beyond Pesticides, September 14, 2010) A new study confirms that indoor uses of consumer products, including pesticides, are the primary sources of indoor exposure to endocrine disruptors —chemicals that disrupt hormones and cause adverse developmental, disease, and reproductive problems— and shows that indoor levels are higher than those outdoors. Researchers from Silent Spring Institute, Columbia University, and the University of California-Berkeley measured airborne concentrations of endocrine disruptors in two California communities: Bolinas, a rural, affluent coastal town, and Richmond, a working-class city ringed by oil refineries. The study is published online in the September 1, 2010 issue of Environmental Science & Technology. The researchers analyzed 104 chemicals in 50 homes, including both chemicals that penetrate indoors from outdoor industrial and transportation sources and those from indoor use of consumer products and building materials. Similar levels of contamination were found inside homes in both communities, but outdoor levels were higher in Richmond. Among the chemicals found were pesticides, phthalates, parabens, PBDE flame retardants, and PCBs. A total of 38 pesticides are evaluated, including banned organochlorines (e.g., DDT, PCP), and current use products such as carbamates (e.g., propoxur), organophosphates (e.g., chlorpyrifos), and pyrethroids (cypermethrin). Thirteen pesticides were detected outdoors and sixteen pesticides […]

(Beyond Pesticides, August 26, 2010) Researchers from Indiana University have detected organochlorine pesticides and flame retardants in blood samples taken from bald eagle nestlings in the Great Lakes region. After DDT was banned, many scientists expected the bald eagle population to recover more quickly, so this study provides some evidence to explain their lackluster rebound. The researchers found not only organochlorines and PCBs (polychlorinated biphenyls), but several flame retardants commonly used in foam padding, such as pentabromoethylbenzene (PBEB), hexabromocyclododecanes (HBCDs) and Dechlorane Plus (DP). The paper, published in the August issue of the scientific journal Chemosphere was authored by Marta Venier of Indiana University. Ms. Venier and her colleagues collected blood samples by climbing trees to access the nests, carrying the nestlings carefully to the ground, and drawing a small blood sample before returning them to their nests. The statistically significant relationship between the total PBDE concentrations and total PCB concentrations suggest that these young eagles are ingesting pesticides and flame retardants through their food. Even low levels of these chemicals could be advsersely affecting the eagle population because as co-author of the study, Ronald Hites of Indiana University says, “Eagles are very vulnerable to chlorinated compounds.” Chlorinated materials are […]

(Beyond Pesticides, June 25, 2010) Two new studies published in the journal Environmental Science and Technology confirm that the majority of toxic contamination threatening national parks originates from agricultural pesticides and industrial operations. In one study an international group of scientists conducted research from 2003-2005 and detected elevated concentrations of various dangerous pesticides in all eight of the national parks and preserves. The other study collected samples of air, water, snow, sediment, lichens, conifer needles, and fish at remote alpine, subarctic, and arctic sites. Researchers found that these samples contained four current-use pesticides including dacthal (DCPA), chlorpyrifos, endosulfans, and y-hexachlorocyclohexane (HGH) as well as four historic-use pesticides including dieldrin, a-HCH, chlordanes, and hexachlorobenzene (HCB). Pesticide concentrations in snow are highest in Sequoia, Kings Canyon, Rocky Mountain and Glacier National Parks. Concentrations in vegetation are mostly dominated by endosulfan and dacthal, and are highest in Yosemite, Kings Canyon, Glacier, and Great Sand Dunes National Park and Preserve. Fish samples also show elevated concentrations of dieldrin and DDT (one of the first pesticides to be banned in 1972 because of Rachel Carson’s Silent Spring). Cold temperatures in alpine or arctic ecosystems tend to concentrate pesticides, which can also bioaccumulate in the local […]

(Beyond Pesticides, June 17, 2010) Researchers have found detectable levels of common household pesticides in the majority of umbilical cord blood of babies born at an urban hospital. The study looks at concentrations of organophosphate (OP), carbamate, pyrethroids, and organochlorine pesticides in samples of umbilical cord blood taken from newborns delivered at the Johns Hopkins Hospital Labor and Delivery Suite in Baltimore. Researchers looked at the umbilical cord serum, as opposed to maternal serum, in order to provide a more direct estimate of exposure to the fetus. While human biomonitoring studies have found detectable levels of these pesticide chemicals in urine and blood samples from children and adults in the past, few studies have been carried out in the U.S. evaluating exposure in utero. In addition to tracking pesticide concentrations, researchers also aimed to identify demographic and socioeconomics factors associated with in utero pesticide exposure. Anonymous anthropometric and sociodemographic characteristics of the mothers and infants were collected along with umbilical cord blood that would have otherwise been discarded. Included in the characteristics collected that researchers considered might affect pesticide exposure risk were: age, race, body mass index, parity, education, health insurance, marital status, smoking, area of residence and housing density. […]

(Beyond Pesticides, June 16, 2010) Men with certain genetic variations who were exposed to some toxic pesticides that are now largely banned run an increased risk of developing Parkinson’s disease, French scientists said Monday. In a study published in Archives of Neurology, entitled “Interaction Between ABCB1 and Professional Exposure to Organochlorine Insecticides in Parkinson Disease,” French researchers found that among men exposed to pesticides such as DDT, carriers of the gene variants are three and a half times more likely to develop Parkinson’s than those with the more common version of the gene. The scientists think the brains of people with the gene variant fail to flush out toxic chemicals as efficiently as those with common versions of the gene, suggesting that environmental as well as genetic factors are important in the risk of Parkinson’s. Alexis Elbaz, MD, PhD and Fabien Dutheil, PhD, of France’s National Institute for Health and Medical Research (INSERM) studied 101 men with Parkinson’s and 234 without the disease to look at links between organochlorine exposure and Parkinson’s disease. The study includes only men, and all of them had high levels of exposure to pesticides through their work as farmers. The scientists found the link was […]

(Beyond Pesticides, May 28, 2010) The repeated exposure to organophosphate and organochlorine insecticides can increase the risk of developing Alzheimer’s Disease (AD) or dementia later in life according to a new study published in the May issue of Neurology. The observational study entitled “Occupational exposure to pesticides increases the risk of incident AD” is one of very few studies to examine a link between pesticides and AD. Researchers lead by Kathleen M. Hayden, PhD of Duke University Medical Center examined residents 65 years and older from an agricultural community in Cache County Utah. Participants were assessed for cognitive ability at the inception of the study and again after 3, 7, and 10 years. Data showed that those repeatedly exposed to any pesticides were more likely to develop AD or dementia. Researchers found a higher incidence of AD among those exposed to organophosphates and organochlorines. The risk of AD associated with organophosphate exposure was slightly higher than the risk associated with organochlorines. Researchers also found an increase in dementia among those exposed to organophosphates or organochlorines; however this increase was not statistically significant. Dr. Hayden said that more research was necessary to determine a causal link. Organophosphates are known to reduce […]

(Beyond Pesticides, April 16, 2010) Every day, children still die of malaria, a devastating disease that is both preventable and curable. In 2009, the United Nations Environment Program (UNEP) and the World Health Organization (WHO) announced a renewed international effort to combat malaria with an incremental reduction of the reliance on the synthetic pesticide DDT. However, efforts to invest in real solutions are often derailed by those promoting DDT as a “silver bullet” for malaria prevention. Tell President Obama that the President’s Malaria Initiative must invest in safe solutions to malaria, not increase reliance on DDT. Sign by April 22nd and you will be included in the petition to mark World Malaria Day. Sign the petition here. DDT, or dichloro diphenyl trichloroethane, while highly persistent in the environment, was initially found to be effective against mosquitoes and the diseases they carry, such as malaria. However, insect resistance to the chemical has been documented since 1946. DDT was banned in the U.S. in 1972 after it was linked to the decline of the bald eagle and other raptors, and it continues to be linked to health problems. A 2007 study finds that women who were exposed to DDT before the age […]

(Beyond Pesticides, April 12, 2010) Environmental, public health, labor and farmworker advocacy organizations from across the country have filed a petition asking the U.S. Environmental Protection Agency (EPA) to rescind the Bush administration era approval of the highly toxic fumigant pesticide methyl iodide in light of troubling new findings uncovered in California studies. The petition was submitted on the birthday of famed farmworker rights advocate Cesar Chavez, who drew national attention to pesticide misuse on grapes in the 1980s. “In 1988, Cesar Chavez again put his life on the line to draw attention to farmworker rights when he protested the use of pesticides with a 36-day, water-only fast,” said Jeannie Economos, Pesticide Safety and Environmental Health Project Coordinator at Farmworker Association of Florida. “Over 20 years later, we should not have to be fighting the same battles. Methyl iodide use takes us in the dead wrong direction for workers, public health and the future of agriculture.” The movement to ban methyl iodide follows the legacy of Cesar Chavez: the pesticide poses significant, direct risks to farmworkers, their families and neighboring communities. Methyl iodide is a water contaminant, nervous system poison, thyroid toxicant and is listed on California’s Proposition 65 list […]

(Beyond Pesticides, April 2, 2010) On Monday, Tyrone Hayes PhD, researcher and professor at University of California Berkley gave a speech at Illinois State University urging the U.S. Environmental Protection Agency (EPA) to ban atrazine completely. Though atrazine has been the go to broad leaf weed killer for America’s corn growers since the 1950’s, evidence continues to build that atrazine is an unacceptable danger to humans and wildlife, and controversy continues as spring planting looms. In response to mounting scientific research, EPA announced last October it would review atrazine’s registration status, and last month announced plans to overhaul drinking water regulations regarding atrazine and numerous other chemicals known to harm human health. Dr. Hayes is one of the preeminent researchers on the effects of atrazine on amphibians. He compares the current loss of amphibians to the bird die-offs in the 1960’s due to DDT. The Journal Star who covered the event called the atrazine issue “one of the most contested environmental debates since PCBs were banned in the 1970s.” The debate has pitted concerned farmers, environmentalists, and human health advocates against conventional corn growers and atrazine manufacturer Syngenta. Syngenta, the Swiss chemical giant, is also facing litigation from several municipalities […]

(Beyond Pesticides, January 14, 2010) Stating that current water-quality criteria does not reflect the latest scientific knowledge, The Center for Biological Diversity petitioned the U.S. Environmental Protection Agency (EPA) to establish new water-quality criteria for numerous endocrine-disrupting chemicals (EDC) under the Clean Water Act. If adopted, it will be a big step in regulating and eliminating persistent and widespread chemicals that damage reproductive functions in wildlife and humans. The Center for Biological Diversity formally requested that the EPA publish water quality criteria and information taking into account overwhelming science about the effects of EDC pollution on January 11. It says that under the Clean Water Act, EPA has a duty to periodically update water quality criteria to reflect the latest scientific knowledge. The petition presents scientific information on endocrine disrupting chemical pollution found in our waters and requests that the EPA promptly update water quality criteria reflecting this scientific information. Last month, legislation was introduced into Congress to explore linkages between hormone disrupting chemicals in the environment and everyday products and the dramatic increase of autism, hyperactivity, diabetes, obesity, breast cancer, prostate cancer and other hormone related disorders. After the identification of endocrine disruptors, the bill, The Endocrine Disruption Prevention […]

(Beyond Pesticides October 22, 2009) At least seven million inhabitants of Moldavia and Ukraine are endangered by 10,000 tons of old pesticides. This has been reported by the International HCH and Pesticides Association (IHPA). According to the organization the EU must act as fast as possible to disarm this ”˜biggest chemical time bomb of Europe.’ This position was adopted at the closure of the 10th HCH & Pesticides Forum of the IHPA in the Czech Republic. During the congress, it became known that in the former Kalush factory in the west of Ukraine there is a stockpile of no less than 10,000 ton of superfluous Hexachlorobenzene (HCB). The factory location along the Dniester River makes the situation extremely hazardous: a single flood and the high concentrations of poison would pollute the natural habitat of some seven million people in the west of Ukraine and Moldavia. Pesticides are threatening tens of millions of people living throughout Europe, Central Asia, and the former Soviet Union, accordding to the statement. There is an estimated 178,000 to 289,000 tons of obsolete pesticides stockpiled throughout the European Union, Southeast Europe, and the former Soviet Union. Ukraine alone has 4,500 storage locations with over 30,000 tons […]

(Beyond Pesticides, September 30, 2009) The Center the Food Safety and the Resource Institute for Low Entropy Systems have petitioned the City of San Francisco and the San Francisco Public Utilities Commission (SFPUC) to immediately suspend the SFPUC’s Compost Giveaway program because the compost is made with sewage sludge which contains toxic chemicals and hazardous materials. The petition, submitted last Wednesday, cites that the distribution of contaminated compost will spread toxic sludge to homeowners’ backyards, increasing the risk of health problems to children and the community. The SFPUC’s compost giveaway program distributes free compost as part of the commission’s recycling efforts to community gardens, school gardens and local residents. The compost is made of sewage sludge, derived as a by-product of wastewater and sewage treatment, and contains heavy metals, pathogens, pharmaceuticals, PCB’s, flame retardants and endocrine disruptors, such as the antibacterial triclosan. “San Franciscans may think they’re getting a gift from the city, but this is no gift. City residents could be at serious risk of poisoning from the application of sewage sludge to local crops and gardens,” said Paige Tomaselli, staff attorney for the Center for Food Safety. “With this petition, we’re strongly urging the Mayor to put an […]

(Beyond Pesticides, September 17, 2009) Last week, the Centers for Disease Control and Prevention (CDC) awarded $5 million to the states of California, New York and Washington to conduct biomonitoring surveys to assess public exposure to chemicals and toxic substances. This will allow the states to determine which environmental chemicals people have been exposed to and how much of those chemicals are in their bodies. Many U.S. residents carry toxic pesticides in their bodies above government assessed “acceptable” levels. Biomonitoring, which measures levels of chemicals directly in people’s blood or urine, has become increasingly helpful for assessing people’s exposure to toxic substances as well as for responding to serious environmental public health problems. The PANNA report “Chemical Trespass: Pesticides in Our Bodies and Corporate Accountability” in 2004, which compiled data from previous CDC biomonitoring surveys found that children, women and Mexican Americans carried the heaviest “pesticide body burden.” Another biomonitoring study by the World Wildlife Fund UK in 2003, revealed that chemicals, such as DDT, which have been banned for decades and are associated with cancer, immune system disorders, and other health problems, are still found in people today. “Biomonitoring measurements are considered the most health-relevant assessments of exposure because […]

(Beyond Pesticides, July 27, 2009) A mother’s exposure to urban air pollutants known as polycyclic aromatic hydrocarbons (PAHs) can adversely affect a child’s intelligence quotient or IQ, according to the new study “Prenatal Airborne Polycyclic Aromatic Hydrocarbon Exposure and Child IQ at Age 5 Years.” PAHs are widespread in urban environments and throughout the world as they have many sources, several of which are related to pesticides, including creosote used for wood preservation, burning pesticide-laden grass seed fields, and exposure to organochlorine pesticides whether banned, yet ubiquitous DDT or the still used insecticide dicofol. Other sources include synthetic turf fields and the burning of coal, diesel, oil and gas, or other organic substances such as tobacco. PAHs have been known to be bioaccumulative, carcinogenic and disrupt the endocrine system. The new study, funded by the National Institute of Environmental Health Sciences (NIEHS), a branch of the National Institutes of Health, the U.S. Environmental Protection Agency and several private foundations, found that children exposed to high levels of PAHs in New York City had full scale and verbal IQ scores that were 4.31 and 4.67 points lower than those of less exposed children. High PAH levels were defined as above the […]

(Beyond Pesticides, July 23, 2009) A new study published in the August 2009 issue of Environmental Toxicology and Chemistry found that insecticides used in highly populated agricultural areas of California’s Central Valley affect amphibians that breed in the Sierra Nevada Mountains to the east. This study adds to the increasing evidence that pesticides impact areas and wildlife species that are miles from sources of pesticide application. Researchers from the Cooperative Wildlife Research Laboratory, Southern Illinois University and U.S. Geological Survey (USGS) examined the chronic toxicity of two of the insecticides most commonly used in the Central Valley- chlorpyrifos and endosulfan, to larval Pacific treefrogs (Pseudacris regilla) and foothill yellow-legged frogs (Rana boylii), the amphibians with declining populations that live and breed in meadows surrounding the Sierra Nevada. The results are discussed in “Toxicity of Two Insecticides to California, USA, Anurans and Its Relevance to Declining Amphibian Populations.” The study used laboratory testing to examine how the insecticides affected the two frogs at environmentally realistic concentrations. During testing, tadpoles were observed at various stages of development to see how the insecticides affected their growth and health. The researchers found that endosulfan was more toxic than chlorpyrifos to both species, and tadpoles […]