What are some ways to reduce the risks to public health in drinking water from Salinas Valley? Andrew Mims Nitrates In Groundwater Presentation ENSTU 300

Introduction Nitrate contamination is a concern for both growers and citizens which has only recently been brought to the attention of agriculturalist since This is an issue which has been allowed to manifest itself for nearly 50 years. Specific areas affected by this issue include the Salinas Valley and Tulare Basin, Santa Maria, Santa Ynez Valley and the Oxnard Plain.

Background What are nitrates? Nitrates (NO3) are an essential source of nitrogen (N) for plants. Nitrogen fertilizers are used to enrich soils, nitrates may be carried by rain, irrigation and other surface waters through the soil into ground water. Human and animal wastes can also contribute to nitrate contamination of ground water. Agricultural practices have been linked to elevated levels of nitrates in drinking water. Wells can become contaminated by nitrates when they are shallow, poorly constructed, or improperly located these wells become more susceptible to contamination. Nitrate levels in drinking water can also be an indicator of overall water quality. Elevated nitrate levels may suggest the possible presence of other contaminants such as disease-causing organisms, pesticides, or other inorganic and organic compounds which cause health problems.

Health Concerns

Location of Groundwater Nitrate Pollution Decades of intensive fertilizer and pesticide use have left a legacy of water pollution in the region’s surface and groundwater. Pesticide pollution is the likely cause of ecological damage in the Salinas river.

Sources of nitrate in groundwater can be considered in 4 categories: 1- Natural sources 2- Waste Materials 3- Row crop agriculture 4- Irrigated agriculture

In regards to surface water sources of drinking water, nitrate in surface water at levels much lower than the drinking water standard may cause eutrophication.

An approach for minimizing agriculturally- based nitrate pollution of groundwater is to limit fertilizer applications in the immediate recharge areas of wells.

Nitrates in water supply in San Juan Bautista found-in-san-juan-bautista-water-supply/ found-in-san-juan-bautista-water-supply/ More recent analysis using nitrate quick tests have shown some wells in Salinas measuring as high as 150ppm.

The graph depicts a five year moving average of the percentage of wells for which the average annual measured concentration exceeded 9 mg/L(background, 22.5 mg/L(half of the MCL), and 45 mg/L(MCL) in any given year. Maximum Contaminant Levels (MCLs) are standards that are set by the United States Environmental Protection Agency (EPA) for drinking water quality. An MCL is the legal threshold limit on the amount of a substance that is allowed in public water systems under the Safe Drinking Water Act. The limit is usually expressed as a concentration in milligrams or micrograms per liter of water

Section 303(d) of the federal Clean Water Act Requires every state to evaluate its waterbodies and maintain a list of waters that are considered “impaired” either because the water exceeds water quality standards or does not achieve its designated use. For each water on the Central Coasts “303(d) Impaired Water’s List” the California Central Coast Water Board must develop and implement a plan to reduce pollutants so that the waterbody is no longer impaired and can be de-listed. In Salinas Valley and the Tulare Lake Basin 2.6 million rely on groundwater. Commissioned by the state water resources control board a 2008 law requires a nitrate study.

Agricultural Order R Regulates discharges of waste from irrigated lands. (3) tiers have been developed and their relative risk to water quality. Purpose of the Agricultural Order is that it requires farmers an landowners to implement management practices, and conduct monitoring and reporting, to ensure that farms are not polluting surface water or groundwater.

Economic Sustainability- The use of various strategies for employing existing resources optimally so that a responsible and beneficial balance can be achieved over the longer term. Environmental Sustainability is defined as the maintenance of the factors and practices that contribute to the quality of environment on a long term basis. Social equity is defined as ensuring that all communities are treated fairly and are given equal opportunity to participate in the planning and decision making process with an emphasis on ensuring that traditionally disadvantaged groups are not left behind.

Stakeholders Primary- Growers and Residents. Secondary- farmers and citizens. Regulators and Land Owners.

Policy Options Environmental Sustainability Economic Sustainability Social Equity Provide Growers with Monetary Incentives to provide community education for residents in regards to nitrate contamination of groundwater. (tax breaks, water credits) + A counter action to the negative build up of nitrates in soil which is passed to groundwater. +Provides more money to train the community and farmers about hazards. +Innovation, education working to lead economic sustainability. +An improvement for a long term quality of life and public health issues for residents. A proactive approach for growers. Regulate farmers and growers to provide community education for residents in regards to nitrate contamination in their groundwater. +tier permitting regulations are enforced. + reduce the further contamination of groundwater. +Compliance with Agricultural Order R (tiers) -Cost of mitigation, enforcement and legal fees. +A method of taking action to improve this public health issue. +Engaging community efforts and health awareness.

Recommendations Provide monetary incentives to growers who provide community education to growers and residents within farming communities. A low cost option to growers with long term benefits which outweigh the costs. Effective communication in regards to health and safety issues with a non English speaking community. This option brings both groups back to the negotiation table.