A recent study of Chinese bulbuls , for example, showed that the proportion of anthropogenic material in nests increased with degree of urbanization. The potential fitness consequences and adaptive significance of this adjustment, however, were not examined. Herein, we examine the occurrence, types, landscape associations, and consequences of anthropogenic nest material in the American crow , a North American species that breeds in both urban and agricultural landscapes. This study is the first to explicitly document the links between terrestrial land cover, anthropogenic nest material, and nest entanglement in a terrestrial songbird.In an early review of entanglement and ingestion of plastic debris by marine organisms, Laist listed three reasons why the significance of marine debris had been disregarded, all of which could apply to terrestrial organisms today: the mechanics of entanglement were so straight-forward that they lacked ‘‘hidden mysteries;’’ encounters between debris and wildlife could have been rare; and the paucity of published reports appeared to confirm this overall rarity. Since that review, however, awareness and concern about the prevalence and problems associated with plastics in the marine environments have grown rapidly, and entire journal issues have been devoted to the topic. Mechanical impacts of plastics on terrestrial organisms, however, are still largely disregarded. We have shown that 85.2% of crow nests along an urban to agricultural gradient contained anthropogenic material, that the amount of material was higher in nests in agricultural areas,plastic plant pot and that the likelihood of entanglement increased with length of anthropogenic material.

All entangled nestlings failed to fledge. Potential for entanglement and associated mortality could be widespread in birds in highly human-dominated landscapes. Anecdotal descriptions of anthropogenic nest material, including string, balloon ribbon, fishing line, plastic bags, paper, and dental floss, have been reported for many of the North American avian species defined as farmland species and/or urban exploiters and adapters. In some of these species, anthropogenic material has been anecdotally linked to entanglement or poor nest success. Birds in urban and agricultural settings may use hazardous anthropogenic materials because they resemble their preferred, natural nest material , analogous to marine turtles ingesting plastic bags because they resemble their jellyfish prey . Some authors have suggested that highly modified environments, in general, could be ecological traps: animals are attracted to settle on the basis of historically adaptive cues, but cannot sustain a viable population because of low habitat quality. Entanglement in anthropogenic nest material can be added to the suite of documented stressors of urban and intensive agricultural landscapes, including toxins, novel predators, pesticide usage, tillage, roads, and disease. In some situations, anthropogenic nest material could be a beneficial resource, enabling nest construction in places where natural materials are limited. Anthropogenic nest material could have other benefits: for example, cigarette butts incorporated into nests reduced the ectoparasite load of some urban birds. How these potential benefits balance the entanglement hazards of some anthropogenic nest materials is unknown. We found that the amount of anthropogenic nest material was greater in the agricultural landscape than the urban landscape, likely due to the ready availability of twine and shade cloth wire in the agricultural settings. The majority of crow nests across this urban and agricultural gradient contained some anthropogenic material, however, and nestling entanglement occurred across this land use gradient. In all environments, therefore, particularly urban, agricultural, and marine, careful disposal potential hazards could reduce the occurrence of nestling entanglement.It is now well recognized that adverse birth outcomes are related to impaired health status later in life.

The normal gestational age typically ranges from 38 to 42 weeks. The World Health Organization has defined preterm birthas delivery before 37 complete weeks of gestation. The PTB rate in the US rose by more than one-third from the early 1980s through 2006 with peak of 12.8% in 2006 and has slightly decreased in recent years . Though survival of infants born preterm has been improved in the last decades due to advancement in prenatal and neonatal care , the survivors of preterm births are at a higher risk of a number of adverse health outcomes later in life such as neuro developmental impairments, respiratory and gastrointestinal complications , and consequently a greater public health burden. However, risk factors for preterm birth remain largely unexplained. Possible factors associated with preterm birth have included race/ethnicity, maternal age, marital status, maternal behavioral factors , other socioeconomic status measures, psychosocial stress, infections, genetics, and environmental toxicants including environmental tobacco smoke, air pollutants, and pesticides . These factors have explained only a small fraction of preterm birth and many others remain unexplored. Therefore, further studies on the modifiable risk factors for PTB will help improve the understanding of the etiology of PTB and develop prevention strategies accordingly. Low birth weight includes infants born preterm, or too small for gestational age . Birth weights vary by infant’s race and ethnicity but the normal range is considered 2,500 grams to 4,000 or 4500 grams. A 2013 U.S. report estimated that about 8% of infants are born LBW . Infants born LBW were reported to have elevated risks for adverse health outcomes in both short and long terms. For example, the mortality rates in infancy are up to 40 times higher for LBW infants compared with normal weight infants . LBW children are at increased risk for asthma and a range of other chronic disease outcomes, such as obesity , hypertension , and kidney disease . The main risk factors for LBW are mostly similar to those for PTB ; however, some factors are different for these two birth outcomes. For example, males are at higher risk for preterm birth but lower risk for term low birth weight . Pesticides have been found in indoor residential dust in residences near agricultural fields, and may persist for years .

Earlier epidemiologic studies using ecological and cross-sectional designs typically reported positive associations for pesticide use in agriculture assessed based on residence and PTB and LBW . However, results from studies assessing self-reported or occupational use of pesticides were inconsistent . Some indicated an increased risk of PTB, LBW, or impaired fetal growth in pregnant women with occupational exposure to pesticides ;while findings from the Danish National Birth Cohort and the Agricultural Health Study suggested little effect of occupational exposures to pesticides on preterm birth and low birthweight. The approaches for studying pesticides in relation to adverse birth outcomes have been improved using Geographic Information System in the last a few decades. A systematic review of 25 early studies examining agriculture-related exposures from residential proximity to pesticide applications suggested weak or no effects on preterm birth and low birth weight,nursery pot possibly due to the methodological limitations such as poor exposure measurement and potentially inadequate control of confounding . Recent residential proximity studies using simple or aggregate-level exposure assessments provided some evidence for pesticide influencing birth outcomes . A northern California cohort study employed a Geographic Information System to estimate methyl bromide use within 5 km of mother’s home during pregnancy using Pesticide Use Reporting records from the California Department of Pesticide Regulation and reported that high methyl bromide use in the second trimester was associated with reduced birth weight  in 1999- 2000. Two recent GIS-PUR based studies restricted to the San Joaquin Valley of California both improved the spatial resolution of pesticide estimates through overlay of matched land use survey maps provided by the California Department of Water Resources, but reported conflicting results. One study assessed pesticides labeled with EPA signal word toxicity by summing up their active ingredients applied in the 2.6 km2 section surrounding maternal residences for more than 500,000 births between 1997–2011 and reported high exposure to pesticides increased risks of preterm birth and low birthweight by 5-9% overall . The other study examined exposure to 543 commonly used specific chemicals or 69 chemical groups by gestational month in 1998-2011 and reported mostly negative associations between spontaneous preterm deliveries and pesticide exposure . The difference can be partly explained by the pregnancy period of interest in these two studies, of which the second largely focused on late pregnancy rather than early or mid-pregnancy, which is believed to be the critical period for exposures causing preterm birth .

Overall about 14 per 100,000 children are diagnosed with cancer in the United States . Although cancer in children is rare, it is the leading disease-related cause of death among children aged 1 to 14 years. In 2018, the estimated incidence of childhood cancers is 10,590, among whom about 1,180 will die from this disease . Among children in the United States, acute lymphocytic leukemia is the most common type of cancer , followed by brain and central nervous system tumors , neuroblastoma , and nonHodgkin lymphoma. A modest rise in age-adjusted incidence was observed for leukemia, brain tumors, and neuroblastoma in the mid-1980s, likely reflecting diagnostic improvements or reporting changes, while dramatic declines in mortality represent improved survival rate due to advancement in treatment . Little is known about the etiology of childhood cancers. The established risk factors including therapeutic doses of ionizing radiation and inherited genetic conditions, together only account for 5- 10% of childhood cancers . Childhood cancer incidence has long been linked to demographic characteristics such age, sex, and race/ethnicity . Other commonly examined potential risk factors include maternal and paternal age, socioeconomic status , and living environment. Advanced maternal and paternal age seems to represent risk factors for several types of childhood cancers including leukemia or brain tumors but the conclusions are inconsistent and vary by cancers. High SES has previously been linked to higher risks for childhood brain tumors , yet a review showed that connections of SES measures to childhood leukemia are likely to vary with place, time, and study design . Living environment could reflex a matrix of factors including housing conditions/types , farm residence , proximity to traffic related or industrial air pollution and air toxics , and infections , which pointed to childhood cancers to some extent. It has been reported that some predisposing or initiating events such as parental occupational exposures to solvents, pesticides, metals, paints, or plastics, and exposures to air pollutants and air toxics, non-ionizing radiation , and home use or agricultural use of pesticide that occur before pregnancy, during fetal life or in infancy may be associated with childhood cancers . Many interview-based, case-control studies published have found an increased risk of childhood cancer with household pesticide use. Overall, these studies reported positive associations with home use of insecticides, mostly before the child’s birth, while findings for herbicides are mixed . Other than household use of pesticides, studies generally supported positive associations between parental occupational pesticide exposures and brain tumors . The association between childhood leukemia and prenatal maternal occupational pesticide exposure was also reported in most studies but evidence is not as strong as that for paternal pesticide exposure . These above mentioned studies assessed pesticide exposure primarily based on parental occupational history or household use, possibly reflecting exposure to a higher dose of exposure to chemical agents, whereas agricultural pesticides near individuals’ residences that drift during application may represent exposures occurring at lower doses. Earlier residence-based ecologic studies linked agricultural pesticide use or agricultural activity to childhood cancers. A California ecologic study that analyzed high vs low agricultural pesticide use at the block group level using California’s pesticide use reporting database in relation to childhood cancer incidence rates among children diagnosed under 15 years of age between 1988 and 1994 generally found no association between pesticide use density and childhood cancer incidence, except for elevated leukemia rates in block groups with the highest use of propargite . Another US-wide ecologic study explored the association between county-level measures of agricultural activity estimated using the 1997 US agricultural census data and risk of cancer in children and showed statistically significant increased risk estimates for many types of childhood cancers associated with residence at diagnosis in counties having a moderate to high level of agricultural activity . For example, children living in counties with high agricultural activity have increased risks for leukemia and central nervous system cancer .