MaineDMR Public Health - 2020 P90 Scores

The Maine Department of Marine Resources Bureau of Public Health (DMR) collects surface water grab samples year-round at approximately 1,400 water quality stations along the Maine coast. Samples are analyzed for fecal coliform bacteria concentrations, and results are reported as the number of colony forming units (individual bacterium capable of forming colonies) per 100mL of water (CFU). Fecal coliform values exhibit wide variability at most water quality stations. For each station, summary statistics are calculated after at least 30 samples have been collected under a systematic random sampling strategy. This information, along with sanitary surveys of the area, help determine whether the water quality is acceptable for harvesting shellfish. The DMR Shellfish Growing Area Classification Program classifies state waters as Approved, Conditionally Approved, Restricted, Conditionally Restricted or Prohibited using standards set by the National Shellfish Sanitation Program (NSSP), a federal/state cooperative program that sets the requirements for all states involved in interstate shellfish harvest and sale. For more information about the classification of shellfish harvesting areas, please visit: https://www.maine.gov/dmr/shellfish-sanitation-management/programs/growingareas/index.html. All classifications are based on two factors: the results of a shoreline survey which looks for the presence of pollution sources, and fecal coliform test results. Two statistical values are calculated from the most recent 30 fecal coliform scores: the geometric mean (geomean) and the geometric 90th percentile (P90). The standards for Approved classification are 14 CFU or less (geomean) and 31 CFU or less (P90). The standards for Restricted are 88 CFU or less (geomean) and 163 CFU or less (P90). The standards for Prohibited are greater than 88 CFU (geomean) and greater than 163 CFU (P90). End of year 2020 P90 data for all active water quality stations are based on the most recent 30 samples from each station. Conditional Area stations are based on last 30 samples in the open status. Data projection is NAD 1983 UTM Zone 19N.缅因州海洋资源部公共卫生局（DMR）全年在缅因州沿岸约1400个水质监测站采集地表水瞬时水样。该机构对样本中的粪大肠菌群浓度进行分析，检测结果以每100毫升水中的菌落形成单位（Colony Forming Unit，CFU，即可形成菌落的单个细菌）计数报告。多数水质监测站的粪大肠菌群数值存在显著变异性。针对每个站点，在采用系统随机采样策略采集至少30份样本后，将计算汇总统计量。此类信息结合区域卫生调查结果，可用于判断水质是否符合贝类采收的相关要求。 缅因州海洋资源部的贝类养殖区分类项目，依据国家贝类卫生计划（National Shellfish Sanitation Program，NSSP）制定的标准，将州内水域划分为批准类、有条件批准类、限制类、有条件限制类及禁止类。国家贝类卫生计划是一项联邦与州级合作项目，为所有参与跨州贝类采收与销售的州制定相关要求。 如需了解更多贝类采收区分类的相关信息，请访问：https://www.maine.gov/dmr/shellfish-sanitation-management/programs/growingareas/index.html。 所有分类均基于两项核心因素：一是排查污染源的岸线调查结果，二是粪大肠菌群检测结果。研究人员将从最近30份粪大肠菌群检测评分中计算两项统计值：几何均值（geomean）与几何90分位数（P90）。 各类别的水质标准如下：批准类要求几何均值≤14 CFU且P90≤31 CFU；限制类要求几何均值≤88 CFU且P90≤163 CFU；禁止类要求几何均值＞88 CFU且P90＞163 CFU。 2020年末所有活跃水质监测站的P90数据，均基于各站点最近30份样本；有条件区域站点的数据则基于其处于开放状态下的最近30份样本。本数据集采用NAD 1983 UTM Zone 19N坐标投影。