{1} In this ease, we review the action of New Mexico’s Water Quality Control Commission (Commission) in revising the water quality standard for uranium in groundwater. We conclude that the Commission properly amended the standard pursuant to NMSA 1978, § 74-6-4(C) (2003), and that credible scientific data existed in the record to support its action. Appropriate review of Appellants’ remaining concerns can be conducted only after the standard has been applied to a fact-specific situation. Accordingly, we affirm.
I. BACKGROUND
A. Facts
{2} In October 2002, the New Mexico Environment Department (Department) petitioned the Commission to revise New Mexico’s numeric human -health standard for uranium in groundwater. See NMSA 1978, § 74-6-6(B) (1993); 20.6.2.3103(A)(12) NMAC. The Department asked the Commission to lower the standard for uranium from 5 milligrams per liter (mg/L) to 0.007 mg/L because of the toxic effects of uranium on the public’s health and particularly because the state has a high Native American and Hispanic population, which is especially susceptible to those effects. 1
{3} Prior to filing its petition, the Department requested public comment from interested parties. Interested parties, including the New Mexico Mining Association (NMMA) and the New Mexico Oil and Gas Association (NMOGA) (together, Appellants), had the opportunity to submit comments and to participate in seven days of hearing, over the course of several months, where substantial scientific, medical, and technical testimony was presented. After public deliberation in June 2004, the Commission voted unanimously to change the numeric standard for uranium in groundwater from 5 mg/L to 0.03 mg/L, pursuant to Section 74-6-4(C). Subsequently, the Commission issued its statement of reasons with its final order, from which Appellants appeal.
{4} The new standard, 0.03 m^L is the same as the United States Environmental Protection Agency’s (EPA) standard for drinking water. See 40 C.F.R. § 141.66(e) (2005). The parties agree that the previous standard, 5 mg/L, is not protective of public health. Because it was the standard in effect at the pertinent times, the 5 mg/L standard was used by uranium operators to develop remediation and closure strategies. Of those mine and mill sites where documentation exists, the groundwater samples at all but one site are in compliance with the 5 mg/L standard. The Commission’s new standard for uranium became effective for new water discharges on September 26, 2004, and it becomes effective on June 1, 2007, for past discharges and discharges in existence as of September 26, 2004. See 20.6.2.3103 note NMAC.
B. Appellants’ Arguments
{5} Appellants challenge the amendment to the numeric standard for uranium on
{6} Appellants contend that the Commission’s action was arbitrary and capricious and a violation of New Mexico’s Water Quality Act, NMSA 1978, §§ 74-6-1 to -17 (1967, as amended through 2005) (WQA), because the revised standard is unattainable. They argue that the Commission was required to adopt the revised standard pursuant to Section 74-6-4(D) and that therefore the Commission acted improperly because it failed to consider technical feasibility and economic reasonableness and failed to establish the existence of “available demonstrated control technology.” Thus, Appellants assert that the Commission failed to engage in reasoned decision making and, consequently, ask this Court to reverse the decision of the Commission. See Atlixco Coal. v. Maggiore,
C. Statutory and Regulatory Framework
{7} An overview of the relevant statutes and regulations is essential to our analysis. The Commission was created by the WQA. See § 74-6-3; Bokum Res. Corp. v. N.M. Water Quality Control Comm’n,
{8} The Commission is administratively attached to the Department, which is a “constituent agency” charged with implementing regulations promulgated by the Commission. Sections 74-6-2(K)(l), -3(F), -8; see §§ 74-6-5, -9; 20.6.2.7(N) NMAC. As a constituent agency under the WQA, the Department is charged with issuing permits for the discharge of water containing identified contaminants, Section 74-6-5(A); 20.6.2.3104 NMAC, and administering regulations regarding abatement of pollution. See § 74-6-4(E); 20.6.2.4104(A) NMAC; see also §§ 74-6-9, -11. The numeric human health standards established by the Commission are incorporated by reference into regulations that guide the Department in its administration of discharge permits and abatement plans. See 20.6.2.3101, .3104, .4103(B), .4104 NMAC. The Department is directed to deny an application for a discharge permit if, inter alia, (1) the discharge would not meet applicable effluent regulations, standards of performance or limitations; (2) any provision of the WQA would be violated, or; (3) “the discharge would cause or contribute to water contaminant levels in excess of any state or federal standard,” to be determined by measuring the effect of the discharge on groundwater “at any place of withdrawal of water for present or reasonably foreseeable future use.” Section 74-6-5(E). Thus, regulations regarding discharge permits incorporate by reference the numeric standard for uranium, and a regulated entity could be subject to consequences for failure to meet the standard. See, e.g., 20.6.2.3101(A)(l)-(2) NMAC (using the standards to determine whether degradation of the groundwater will be allowed); 20.6.2.3107(A)(11) NMAC (requiring a closure plan that will “prevent the exeeedance
{9} Regulations regarding abatement plans also incorporate the numeric standard for uranium. See 20.6.2.4103(B) NMAC (requiring abatement of groundwater pollution, at any place of withdrawal for present or reasonably foreseeable future use, to conform to the groundwater standards); see also 20.6.2.4101(B) NMAC (requiring abatement by the person responsible for a background concentration of a water contaminant that exceeds the groundwater standards). The purpose of the abatement regulations is to remediate or protect all groundwater for use as domestic and agricultural water supply. 20.6.2.4101(A)(1) NMAC. If a person responsible for contamination cannot meet the abatement standards through the use of appropriate technology and procedure, the secretary may approve a technical infeasibility proposal involving the use of experimental abatement technology, provided the resulting concentration of contaminants is no greater than 200 percent of the standard for that contaminant. 20.6.2.4103(E) NMAC. If the 200 percent limit on concentration is technically infeasible, the responsible person may file a petition with the commission for alternative abatement standards or for a variance. 20.6.2.4103(E)(3) NMAC; see also 20.6.2.4103(F) NMAC. The petitioner must show either that compliance is technically infeasible when the responsible party makes “the maximum use of technology within the economic capability of the responsible person,” or that “there is no reasonable relationship between the economic and social costs and benefits.” 20.6.2.4103(F)(1)(a) NMAC. In addition, the responsible person must show that the proposed alternative standards are achievable, justifiable, and will not cause undue damage to property or create a present or future hazard to public health. 20.6.2.4103(F)(l)(b)-(c) NMAC.
II. DISCUSSION
A. Standard of Review
{10} As an appellate court, we ask whether the Commission’s action was arbitrary, capricious, or an abuse of discretion; not supported by substantial evidence in the record as a whole; or otherwise not in accordance with law. Section 74-6-7(B). We address Appellants’ arguments first in the context of each standard of review. We then address the remaining arguments. Because Appellants’ arguments rest on the assertion that the Commission must act pursuant to Section 74-6-4(D), we begin by asking whether the Commission acted in accordance with law when it adopted the revised standard pursuant to Section 74-6-4(C).
B. Otherwise Not in Accordance With Law
{11} A ruling that is not in accordance with law should be reversed “if the agency unreasonably or unlawfully misinterprets or misapplies the law.” Archuleta v. Santa Fe Police Dep’t,
{12} When construing a statute, we begin with the plain language, and we assume that the ordinary meaning of the words expresses the legislative purpose. Regents of the Univ. of Cal. v. N.M. Water Quality Control Comm’n,
{13} Appellants contend that the Commission must adopt a revised standard pursuant to Section 74-6-4(D) and thus were required to consider technical feasibility and economic reasonableness of the proposed standard. The Commission, according to Appellants, must determine that a proposed standard is “achievable through application of the best available demonstrated control technology, processes, operating methods or other alternatives” before adopting that standard. See Section 74-6-4(D). We disagree.
{14} The plain language of the statute supports the Commission’s action when it adopted the revised standard pursuant to Section 74-6-4(C). Subsection C delegates authority to the commission to adopt water quality standards and provides guidance for adopting these standards: “In making standards, the commission shall give weight it deems appropriate to all facts and circumstances, including the use and value of the water for water supplies, propagation of fish and wildlife, recreational purposes and agricultural, industrial and other purposes}.]” Section 74-6-4(C). In contrast, Subsection D delegates authority to the commission to adopt regulations for the prevention and abatement of water pollution and provides guidance for adopting these regulations: “In making regulations, the commission shall give weight it deems appropriate to all relevant facts and circumstances, including ... the social and economic value of the sources of water contaminants [and] technical practicability and economic reasonableness of reducing or eliminating water contaminants from the sources involved}.]” Section 74-6-4(D)(2)-(3). The plain language of each subsection, “in making standards” and “in making regulations,” indicates the legislature’s intent to distinguish both between water quality standards and regulations regarding water pollution and between the procedures by which each are adopted. See § 74-6-4(C)-(D).
{15} Appellants rely on additional language in Subsection D to argue that the Commission must make a determination that the standard was achievable: “Regulations ... may specify a standard ... that the commission determines to be achievable through application of the best available demonstrated control technology, processes, operating methods or other alternatives[.]” Section 74-6-4(D). Appellants read this language out of context. The sentence reads in full:
Regulations shall not specify the method to be used to prevent or abate water pollution but may specify a standard of performance for new sources that reflects the greatest reduction in the concentration of water contaminants that the commission determines to be achievable through application of the best available demonstrated control technology, processes, operating methods or other alternatives, including wherepracticable a standard permitting no discharge of pollutants.
Id.
{16} Read in context, the language upon which Appellants rely is a condition limiting the commission’s authority to adopt regulations that specify a standard of performance for new sources. Reading the language of all the provisions of the statute together, we conclude that the legislature intended to distinguish between factors the Commission could consider when adopting a water quality standard, see § 74-6^4(C), and a determination that the Commission must make when it adopts a regulation that specifies a standard of performance for new sources. See § 74-6-4(D). Appellants do not argue that the Commission specified a standard of performance for new sources. Thus, we conclude that the legislature intended the commission to consider the factors identified in Subsection C when it adopts water quality standards to protect human health. See 74-6-4(C) (“The standards shall at a minimum protect the public health or welfare, enhance the quality of water and serve the purposes of the Water Quality Act.”). We hold that the Commission acted in accordance with law when it adopted the revised water quality standard for uranium because the Commission did not unreasonably or unlawfully misinterpret or misapply the authorizing statute. Cf. Archuleta,
{17} Our interpretation of the current statutory language is supported by Regents,
{18} While we recognize that Regents dealt with water quality standards as incorporated in surface water regulations and enacted to comply with minimum standards established by the federal Clean Water Act, see Regents,
{19} Appellants rely on Tenneco to support their claim that when the commission adopts a new standard, the commission must determine achievability by considering the “technical practicability, economic reasonableness, and previous experience with the methods available.” See
{20} Appellants further argue that the Subsection D factors for adopting regulations “should at least be considered” because the standards have been incorporated into discharge and abatement regulations, and the Commission thus adopted a standard that will require the mining industry to abate groundwater to an unattainable standard. The regulations prohibit discharges that will result in concentrations of a contaminant in excess of the standards. See 20.6.2.3106(C)(7) NMAC (providing that a proposed discharge plan will include “[a]ny additional information that may be necessary to demonstrate that the discharge permit will not result in concentrations in excess of the standards”). The regulations also require abatement to meet these standards in groundwater. 20.6.2.4103(B) NMAC (“Ground-water pollution at any place of withdrawal for present or reasonably foreseeable future use ... shall be abated to conform to the [groundwater] standards.”). The Department agrees: “These standards are applicable to discharges of effluent and leachate ... that may affect groundwater, and also to abatement, or clean-up, of groundwater that has been contaminated by discharges.” It is not clear under the facts of this case, however, how the new numeric standard will be applied as an abatement standard. The new standard has not yet been applied to a discharge or an abatement at a uranium mine or mill site. Nor is it clear how the old numeric standard was applied as an abatement standard. Appellants’ brief-in-chief discusses abatement that has taken place under the old standard of 5 mg/L: “Through 20 years of [pump-and-treat technology], ... contamination at one New Mexico site has been reduced from a high of [4-5 mg/L] ... to a more acceptable level of [2-4 mg/L] at monitoring points adjacent to the tailings.” Clearly, there are considerations requiring technical expertise that preface the determination of how a standard is applied to a particular site. Cf. Phelps Dodge Tyrone,
{21} We understand the concerns expressed by Appellants regarding the feasibility of groundwater abatement using the new standard at a mine or mill site. However, the posture of the case at hand does not present the facts necessary for appellate review
C. Arbitrary and Capricious — Consideration of the Statutory Factors
{22} An agency action is arbitrary and capricious if it is unreasonable, if it provides no rational connection between the facts found and the choices made, or if it entirely omits consideration of important aspects or relevant factors of the issue at hand. Sierra Club,
{23} The Commission made its decision after considering the following facts presented in proceedings below. The new standard is the same as the United States Environmental Protection Agency’s (EPA) standard for drinking water. See 40 C.F.R. § 141.66(e). Public water supply systems supplied by groundwater must meet the EPA drinking water standard. Approximately ninety percent of the people in New Mexico rely on groundwater for drinking water, and approximately ten percent of the population obtain their drinking water from private supply systems that are not subject to the federal drinking water standards. A witness for NMMA testified that a standard for groundwater expected to be used for domestic purposes should be the same as the drinking water standard. In setting the federal standard, the EPA determined that available scientific evidence indicated 0.02 mg/L would be protective of public health. It established a standard of 0.03 mg/L, however, because the health benefits of requiring 0.02 mg/L instead of 0.03 mg/L were minimal compared to the costs saved by permitting 0.03 mg/L. Moreover, the United States Court of Appeals for the District of Columbia ruled that the scientific evidence used by the EPA to set its standard of 0.03 mg/L for uranium was reasonable. City of Waukesha v. EPA,
{25} After considering this testimony, the Commission concluded that a drinking water standard was appropriate for use as a groundwater standard because ninety percent of New Mexicans drink groundwater and because the groundwater is delivered to ten percent of New Mexicans through private supply systems that are unprotected by the EPA drinking water standard. The Commission also concluded that credible scientific data and other appropriate evidence indicated the uranium standard should be 0.03 mg/L. Although scientific evidence was presented by the Department in support of a lower standard (0.007 mg/L) for protection of public health, the Commission considered testimony regarding the difficulties of compliance with two different standards, for federal and state regulations, and determined that the revised standard should be the same as the federal standard. Thus, the Commission amended the uranium standard to 0.03 mg/L, instead of the proposed 0.007 mg/L, in order to fulfill its duty to “at a minimum protect the public health or welfare, enhance the quality of water and serve the purposes of the Water Quality Act.” See § 74-6-4(C).
{26} The Commission considered these facts, relevant to Subsection C, regarding the use and value of the groundwater for domestic water supply and for mining purposes, and engaged in public deliberation before it unanimously adopted the revised standard. We cannot say that the Commission failed to engage in reasoned decision making as defined by Section 74-6-4(C); thus, we conclude that the Commission’s action was not arbitrary and capricious. Tenneco,
{27} Appellants rely on National Lime Association v. EPA,
{28} Appellants also rely on Industrial Union Department, AFL-CIO v. American Petroleum Institute (Benzene),
{29} Appellants cite to a number of cases arguing that the Commission must determine a standard to be technologically feasible before it can be adopted. Given our conclusion that the water quality standard was properly adopted pursuant to Section 74-6^4(C), and the distinction we have made between standards imposed for water quality and standards imposed for effluent or discharges, these cases cited by Appellants are also inapposite. See Am. Fed’n of Labor & Cong, of Indus. Orgs. v. OSHA,
D. Substantial Evidence — Credible Scientific Data
{30} Substantial evidence is evidence that a reasonable mind would recognize as adequate to support the conclusions reached by a fact-finder. Wagner v. AGW Consultants,
{31} Section 74-6-4(C) provides that the standards shall be “based on credible scientific data and other evidence appropriate under the Water Quality Act.” The Commission heard testimony from the Department’s three experts, all of whom testified in support of amending the standard to 0.007 mg/L. The Commission relied on the peer-reviewed Lewis study that addressed the toxic effects of uranium on humans, particularly chemical toxicity on the kidney. The Lewis study reviewed non-human animal studies of uranium toxicity and human exposure data and used an EPA recognized methodology, the exposure dose approach, to estimate a numeric standard for uranium in drinking water, 0.007 mg/L, that is protective of human health. The 0.007 mg/L proposed standard was based in part on the high incidence of kidney ailments that exist in several New Mexico populations, especially Native American and Hispanic communities, which are often located in areas of uranium deposits.
{32} The EPA methodology and the Lewis study documented uncertainty factors that were used to correct for uncertainties resulting from various extrapolations, within and between species, as well as other factors. Clinical studies of the effects of uranium on humans are not available because it is unethical to knowingly subject persons to a harmful exposure. One study, however, shows that people exhibited subclinical effects to their kidneys after being exposed to average concentrations ranging from 0.005 mg/L to 0.196 mg/L. The Commission also considered City of Waukesha, which held that the EPA’s use of epidemiological data and non-human animal studies to set a drinking water standard for uranium of 0.03 mg/L was reasonable.
{34} Viewing the record as a whole, we conclude that substantial evidence exists in the record, based on credible scientific data, to support the Commission’s actions. See Bokum,
E. Alternative Abatement Plans
{35} Appellants argue that the opportunity to petition for Alternative Abatement Standards (AAS), see 20.6.2.4103(F) NMAC, does not cure an “otherwise defective” regulation. Appellants contend that the AAS process involves a discretionary variance procedure, “haphazard at best,” which allows a regulation to be applied using a “standard dujour.” See Bokum,
F. Incorporation of the Standards Into Oil and Gas Regulations
{36} For the reasons discussed throughout the opinion, we conclude that the concerns of the NMOGA regarding implementation of the revised standard can be adequately reviewed only after the revised standard has been applied in a fact-specific manner. However, we briefly address NMOGA’s other arguments. With inaccurate citations to the record, NMOGA asserts that the Commission’s action was improper because the Commission failed to consider the effect of the revised standard on the Oil Conservation Division’s (OCD) regulatory scheme and the oil and gas industry and because the Oil Conservation Division was not a party to the proceeding. We disagree. First, we observe that the Commission did hear testimony from the NMOGA. NMOGA’s witness appeared on the final day of the hearing to ask the Commission to delay its revision of the standard, so the industry could look at the impact of the revised standard and provide that information to the Commission. The witness testified that he had “no expertise or teehnical
{37} Second, Section 74-6-3(A)(4) specifically provides that the commission shall include the chairman of the oil conservation commission or a designated member of his staff. See generally NMSA 1978, § 70-2-4 (1987) (providing for the creation of the oil conservation commission); NMSA 1978, § 70-2-6 (1979) (discussing the jurisdiction of the division and the commission). NMO-GA does not argue that the Commission failed to comply with Section 74-6-3(A)(4). Without more, we cannot conclude that the representative of the oil conservation commission, sitting as a member of the Commission as statutorily required, does not adequately represent the interests of the OCD and the industry it regulates.
III. CONCLUSION
{38} The Commission properly adopted the revised water quality standard for uranium pursuant to Section 74-6^4(C). Concerns regarding the application of the standard can be adequately addressed only after the standard has been applied. Accordingly, we affirm the action of the Commission.
{39} IT IS SO ORDERED.
Notes
. Appellant refers to the standard in parts per billion (ppb). The Final Order uses micrograms per liter (g), at least one of the witnesses uses parts per million in his testimony, and the regulation that contains the standard uses milligrams. We use milligrams per liter (mg/L) because this is the measurement used in the regulation that identifies the standard. See 20.6.2.3103(A)(12) NMAC.