Related by context. Frequent words. (Click for all words.) 61 PCBs polychlorinated biphenyls 61 Infestations 60 pesticide DDT 58 dieldrin 57 polychlorinated biphenyls PCBs 56 overhunting 56 chlordane 55 amphibian populations 55 Contaminants 54 sea lampreys 54 Algae blooms 54 chytrid fungus 54 Peregrine falcons 54 suspected carcinogen 53 overfishing pollution 53 red legged frogs 53 PCBs 52 Toxic chemicals 51 habitat degradation 51 Suburban sprawl 51 DDT 51 carcinogenic chemicals 51 whirling disease 51 Gypsy moths 51 invasive insect 51 honeybee population 51 synthetic estrogen 51 Cyanobacteria 50 toxic algae blooms 50 Soil erosion 50 amphibian species 50 Sea otters 50 contaminants 50 polychlorinated biphenyls 50 Invasive species 50 overharvesting 50 Invasive plants 50 White Nose Syndrome 50 Dust mites 50 polybrominated diphenyl ethers 50 diazinon 50 mold fungi 49 loosestrife 49 honeybee colonies 49 polluted waterways 49 microscopic algae 49 Dioxins 49 endocrine disruption 49 bioaccumulation 49 pesticides 49 carbon tetrachloride 49 Zebra mussels 49 PBDEs 49 Didymo 49 federally endangered species 49 viral hemorrhagic septicemia 49 Pollutants 48 flame retardant chemicals 48 bee populations 48 Brood X 48 chlorinated solvents 48 Feral hogs 48 freshwater mussels 48 contaminant 48 aquatic invertebrates 48 seagrasses 48 carbaryl 48 varroa mites 48 PFOS 48 Quagga mussels 48 snowy plovers 48 mold infestation 48 chlorofluorocarbons CFCs 48 parasitic worm 48 Bed bugs 48 PCB contamination 48 round gobies 48 Paraquat 48 trichlorethylene TCE 48 pyrethroids 48 nonnative fish 48 Bald eagles 48 guillemots 48 lindane 48 intersex fish 47 Overfishing 47 endocrine disruptors 47 spiny dogfish 47 PBDE 47 organophosphate 47 Bubonic Plague 47 endocrine disrupting chemicals 47 freshwater ponds 47 frogs toads 47 endocrine disruptor 47 Hydrilla 47 Emerald ash borer 47 lowland forests 47 Milfoil 47 trigger allergic reactions 47 cordgrass