Environmental engineers design and permit all different types of environmental operations, including water treatment plants, waste-water treatment plants, solid waste facilities, and water and waste-water collection and distribution systems. Engineers can also design remediation systems to clean contaminated soil and groundwater. Engineers can work for federal, state, or local regulators overseeing operations in their district. They can also work in the private sector for consulting firms whose clients include cities and counties with environmental projects and operations.

Environmental journalists research and write on environmental topics. They can work for nonprofit groups or media outlets as media consultants or correspondents. It is their responsibility as environmental journalists to be objective and present facts, not simply to promote propaganda or someone else's agenda. This requires an understanding of the topic, and the journalist must interview various professionals with different perspectives.

Geologists and hydrologists work for industries and regulatory agencies independently as consultants. They use their knowledge of the subsurface to evaluate groundwater quality and availability. In areas where groundwater is the primary source of drinking water, geologists and hydrologists determine impacts from overpumping and look to alternative supplies. In industry, they often work with mining and oil corporations. When groundwater has been contaminated, geologists and hydrologists assess the degree and extent of contamination.

Ecologists often advise groups that want to construct projects for potential environmental effects of the development. They survey areas, determining what species of flora and fauna exist and what impacts a project would have on the populations. They can work to eliminate negative impacts and suggest alternate approaches or supplemental work to enhance a project.

Toxicologists work to protect the public from environmental impacts. Many circumstances arise where chemicals are released, exposing the public. It's the job of a toxicologist to evaluate the impact of those releases. Often, this is performed through a risk assessment through which the toxicologist calculates the possibility that a given contaminant at a given concentration will cause a disease. Toxicologists often work in the chemical and pharmaceutical industries and for regulatory agencies.

Conservation scientists work to protect natural resources like soil, rangeland, and water. They develop plans and make recommendations to allow use of the natural resources with the least amount of environmental impact. With respect to soil, a conservation scientist might recommend ways to reduce erosion. With water, the scientist evaluates how to protect quality while providing drinking water to the public.

Foresters usually work with private timber companies or landowners, making sure that regulations are met when wood is harvested. They also work to encourage the healthy growth of forests and make recommendations when alternative operations or equipment should be considered.

Environmental lawyers work for regulators, private industry, and activist organizations to interpret the meaning and applicability of environmental laws. It is not uncommon to see environmental lawyers on either side of a dispute, representing clients charged with polluting the environment and regulators that want the situation corrected. In working with activist organizations, lawyers often press the government to enhance enforcement actions or pass stricter legislation.

Urban and regional planners work to balance the needs of a community. They must take into account growth and expanded infrastructure, such as water and wastewater facilities. Most planners work for local government agencies and are required to attend public meetings.

Wildlife biologists study how animals live in either human-made or natural environments. Their roles may be similar to or overlap with ecologists. Wildlife biologists can be employed to determine what animals exist in a certain area and how changes may impact their populations. This is of particular importance in areas where endangered or threatened species exist.

Solid waste managers work for cities and counties and handle issues with garbage collection and disposal. They usually work with outside consultants to help design transfer stations, landfills, and incinerators while making sure regulations are met. Solid waste managers educate the public in matters of disposal practices and recycling and can be key players in determining economical ways to recycle and discourage waste.

Wastewater treatment plant operators run facilities that treat sewage. Sewage is processed through a plant where waste is collected and removed. The end result is treated water and sludge, a mud-like material that requires proper disposal. Properly run wastewater treatment plants abide by federal and state regulations. Treated water is often discharged to bays or rivers, while sludge is taken to a landfill or — depending on contaminant concentrations — used as fertilizer for farming operations.

Park rangers operate parks, ensuring that the environment and wild-life are in good condition, and they also work to educate the public. They maintain facilities and make sure they are safe for animals as well as the people who visit. Some rangers with wildlife rehabilitation facilities provide a place for rehabilitating and releasing injured animals.