Rancocas Watershed Study: Pesticides in the Creek

Last edited March 5, 2003

By Jane Nogaki

Cutting Pesticide Use: Everyone's Job

Watershed 19 covers 360 square miles from the headwaters in Manchester Township, Ocean County, to Berlin Township in Camden County, and empties into the Delaware River between Riverside and Delanco. Population centers are Pemberton, Medford, Medford Lakes, Evehsam, Mount Holly, and Willingboro. Forests cover about 40% of the drainage basin, while the agricultural and urban areas take up 30% and 17%.

A recent "snapshot" study of pesticides in the Rancocas Creek watershed highlights the need for everyone to do their share in reducing pesticides, whether it's on the home lawn, the local athletic field, the golf course, or the farm. The study, commissioned by the Burlington County Freeholders with a grant from the NJ Department of Environmental Protection brings home the point that what we put on the land eventually winds up in our waterways.

Mark Robson, Ph.D. of the University of Medicine and Dentistry of NJ along with Eric Vowinkel, Ph.D. of the US Geological Survey and Roy Meyer of NJDEP conducted the study from August, 2001 through July, 2002 on the North Branch, South Branch, and Southwest Branch of the Rancocas Creek. The study was a pilot project, limited in scope and duration, which targeted areas with certain uses: recreational, residential, and farming. Samples were taken at public access areas along county roadways, and, thus, yield general information about the predominant upstream activity, not any individual landowner's impact

The study found low levels (parts per billion) of 30 different pesticides in the stream water samples taken from one site in each of the towns of Easthampton and Medford and two sites in Southampton. Four sites were sampled three times in a year (August, 2001 - May, July, 2002). Because of the drought, storm event runoff was never sampled. Likely higher detections would have been found after heavy rain events. The greatest numbers of pesticides detected were in May with a lesser number detected in the July and August samplings. These months constitute the growing season and thus a greater amount and variety of pesticides are likely to be used in these months.

Stream flow changes also affect the mobility of pesticides. Stream flow, also called discharge, is the volume of water flowing per unit time. The study found that in times of faster stream flow, greater numbers of pesticides were detected, although at lower concentrations. In Watershed 19, the general trend indicated that pesticide concentrations are highest soon after crop, lawn and golf application (May through June).

Three pesticides, atrazine, diazinon, and carbaryl, were found at all four locations. A number of other pesticides, namely metalochlor, prometon, and simazine, were found in 3 of the 4 sampling sites. Three related compounds, atrazine, cyanzine, and simazine, are under special review by the EPA because of concerns over potential risks to human health.

Fifteen of the 30 pesticides were found at more than one site. The number of pesticides detected in each sample ranged from a low of 4 to a high of 19 and on average, 7 to 15 pesticides were found per site. While none of the individual pesticide levels violated drinking water or health advisory standards, the largely unknown effects of the combinations of pesticides on human health or wildlife, i.e., the "cocktail effect" - remain a concern. For fifteen of the pesticides detected, no drinking water or health standards have been established. Ten of the pesticides detected are possible or probable carcinogens and/or endocrine disruptors; some are nervous system toxins.

Findings of the Burlington County Pesticide Study Pilot Project

Thirty different pesticides were found in the part per billion range.

Twelve pesticides were found at the residential and farm sites.

Twenty-two pesticides were found at the golf course site.

Three pesticides were found at all four sites: the weedkiller atrazine and the insecticides carbaryl, and diazinon.

For fifteen of the pesticides, there were no exceedances of drinking water standards or health advisories. For the other fifteen pesticides detected there are no standards of safety established.

Ten of the pesticides found are considered possible or probable carcinogens.

What YOU can Do

People are exposed to pesticides through many ways: residues on food, in drinking water, on lawns and golf courses, inside buildings where pesticides might be applied for pest control. Pesticides can be ingested, inhaled, or absorbed through the skin. The body excretes some pesticides readily; others are stored in body fat and accumulate over time.

Children, particularly the developing fetus, are more vulnerable to the hazards of pesticides than adults and are more exposed because of their dietary/water intake, rapid respiration, and hand-to-mouth behavior.

What can people do to reduce pesticide use, both to protect the environment, surface and groundwater in the watershed, and to reduce their own personal exposure? Practice "least toxic" lawn and garden care. Avoid pesticide use on your own property, but if you do use pesticides, follow the directions and apply at the rate specified on the label, only when and where needed.

Encourage the golf courses in your community to do the same. Tolerate brown spots and understand it doesn't have to be perfect. There's an environmental cost to highly maintained velvet green turf.

Support "Jersey Fresh" local farms. Buy organic and/or buy local whenever possible. Wash fruits and vegetables under running water, and peel when possible.

Encourage your town and school system to adopt an Integrated Pest Management policy for managing pests in environmentally friendly in schools and parks.

For a free brochure on "Lawn Care Without Toxic Chemicals" or help adopting an IPM policy, send a self addressed stamped envelope to the NJ Environmental Federation, 223 Park Ave., Marlton, NJ 08053.

Rutgers Cooperative Extension has extensive information on low maintenance, drought tolerant lawns and landscapes and on local Jersey Fresh farm stands/pick your own farms. Contact Ray Samulis at 609-265-5050.


The low concentrations of pesticides found are reassuring in terms of reducing human health concerns, but the limited sampling performed for the study makes it difficult to make the conclusion that Watershed 19 is absolutely safe. Continued assessment of the type and quantity of pesticides present in the watershed is essential. As patterns of land use change in Burlington County, pesticide use will change also. Knowledge gained from water quality assessments can be used to develop strategies to control the presence of pesticides in the water to ensure the safety of the Watershed's users.

Jane Nogaki
New Jersey Environmental Federation
223 Park Avenue
Marlton, NJ 08053
(856) 767-1110
E-mail: janogaki@eticomm.net