We live in a world of toxic substances. There are the pesticides, hormones, antibiotics, food additives and genetically modified organisms that lace much of our food supply. There are chemicals we use to clean our homes and our clothing, and the environmental pesticides, industrial toxics and other chemicals that plague Mother Earth.

We ingest and are exposed to thousands of chemicals every day, many of which have never been thoroughly tested for their health effects on humans or on other organisms.

While scientists look for the health impact of potential toxic substances in our environment, it often takes decades before a worrisome chemical is finally withdrawn from the market.

And even after these are withdrawn, many of them remain in the environment and in human tissue for years following exposure, including dioxin, PCBs and mercury.

Two new studies about the effects of toxics in our environment shed new concern about their impact on human health. Earlier this month, a study was published in the journal Diabetes Care looking at the effect of phthalates on the risk of diabetes.

In this study of more than 1,000 seniors in Sweden, researchers found that phthalate metabolites in the bloodstream were associated with a 25 percent to 35 percent increased risk of diabetes. Phthalate metabolites may reduce insulin secretion or increase insulin resistance, thus leading to diabetes.

Phthalates, also known as "plasticizers," are industrial chemicals that are added to plastics, cosmetics and medical devices to help keep them soft and flexible; they are ubiquitous in our environment, found in hundreds of consumer products, from toys and vinyl flooring to nail polish, lipstick and shampoo.

They are also in our food and water supplies.

Phthalates are part of a group of chemicals known as "endocrine disruptors," meaning they can disrupt the normal functioning of the hormones in the human body. Because of these concerns, Congress banned several phthalates in children's toys in 2008, but these chemicals persist in the many other products in which they are still used.

This new study supports the concerns about the impact of phthalates on the endocrine system.

The second study, from the UC Davis MIND Institute and Washington State University, looked at the potential impact of PCBs on autism. PCBs, or polychlorinated biphenyls, are industrial chemicals that were extensively used in insulation materials, engine fluids, paints, plastics and multiple other products.

Their production in the United States was stopped in 1977 because of health and environmental concerns, but they remain in the environment for years and are still considered a health hazard.

They can cause multiple health problems, including damage to the endocrine and reproductive systems, the nervous system and the immune system. They can also cause miscarriage as well as health problems in infants who are exposed to PCPs in-utero or from breast milk.

In this new study, scientists found that rat pups born to mothers that were exposed to PCBs had significant changes in certain brain tissues that may add to the risk of autism in children who are genetically at risk for this disorder. The PCB exposure was felt to be similar to what humans are exposed to.

So what can one do to reduce exposure to environmental toxics? Start by eating organic food, especially the most heavily contaminated ones such as apples, celery and strawberries. Use safe cleaning products in your home, and avoid the use of pesticides in your lawn and garden.

Shop for cosmetics and lotions that are free of phthalates and other chemical additives. Store food in glass containers and avoid drinking beverages that have been stored in plastic containers. For lots of great information on other ways to protect yourself and your family, look up the Environmental Working Group at www.ewg.org. The website www.scorecard.org also provides information about environmental toxics that are of concern in your area.

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