Increases in Mortality for All Causes and All Cancers Combined before and after Startup of a Nuclear Power Plant in New Jersey, USA

The Salem/Hope Creek nuclear plant in southern New Jersey is one of just four U.S. plants with three large reactors (all others consist of one or two). These reactors started operations in 1976, 1980, and 1986 and routinely released toxic radioactive gases and particles into the environment. Only a single study has been performed by federal officials on cancer near nuclear plants—a study now 30 years old. A review of official mortality data using four-year periods shows the Salem County cancer death rate was consistently just below that of other New Jersey counties up to the mid-1980s. However, from 1983-1986 to 2015-2017, the county rate soared from −5.4% below the rest of the state to +32.6% above. The county/state mortality ratio for all causes also increased rapidly in these periods, from +0.6% above to +28.4% above the state. Salem now has the highest cancer death rate, and the 2 highest total death rate of any New Jersey county. Had the 1983-1986 county-state ratios not changed in the following 31 years, 3493 fewer deaths (1018 of them from cancer) would have occurred among Salem County residents. The lack of any apparent etiologies that could have caused such a dramatic and unexpected change, plus the fact that the Salem/Hope Creek reactors are aging, corroding, and more prone to leaking radionuclides, emphasizes the immediate need for more studies of this type, and the inclusion of local health as a crucial factor in public decisions on the plant’s future.


Journal of Environmental Protection
1950s has added a new set of harmful man-made chemicals into the environment. In the United States, with 98 nuclear reactors producing about 19 percent of the nation's electricity as of early 2019, the issue of measuring any decline in health status is raised [1]. Despite the large number of reactors operating over decades, the U.S. federal government has only produced one health study in populations living near nuclear plants, a 1990 review of cancer mortality. The study was only done after Senator Edward Kennedy raised the issue to the National Institutes of Health [2].
The federal National Cancer Institute could not conclude whether the addition of radioactivity in the environment was or was not linked to cancer mortality. The fact that only reactors that started operations before 1982 were studied means that many of today's operating reactors were excluded or just several years of post-startup data were used. Despite the Institute's recommendation that further analyses should be conducted, no federal study has been performed in the nearly three decades since then [3]. With 49 of 98 reactors operating more than 40 years-the original period regulators permitted electric companies to operate and many more approaching the 40-year mark, it indicates studies are needed near the plethora of aging and corroding reactors.
Most U.S. nuclear plants consist of 1 or 2 reactors. Only four plants operate three reactors (Browns Ferry, Alabama; Oconee, South Carolina; Palo Verde, Arizona; and Salem/Hope Creek, New Jersey). While Palo Verde has the greatest capacity of any U.S. nuclear plant at 4341 megawatts electrical, the fact that these reactors began operating much later than most plants means the three-reactor plant with the second largest capacity (Salem/Hope Creek, with 3363) has possibly produced the most radioactivity of any operating U.S. nuclear plant [4].
One relative indicator of how much radioactivity has been produced by nuclear plants is the amount of radioactivity stored as nuclear waste. At the end of 2010, Salem had the 22 nd greatest amount of such waste of 72 U.S. nuclear plants, a total of 216,050,800 curies. The current number is considerably greater, and Salem/Hope Creek's ranking is higher. By contrast, the estimated 150,000,000 curies were released from the catastrophic meltdown at Chernobyl [5]. Although the waste includes several dozen radionuclides that decay slowly, about 90% of the waste is made up of three chemicals: Cesium-137, Plutonium-241, and Strontium-90.
The purpose of this analysis will be to review trends in cancer mortality near the Salem/Hope Creek nuclear plant, following the manner that the National Cancer Institute took in 1990. In addition to cancer, mortality trends for other causes of death will be explored. Also similar to the National Cancer Institute, mortality for all cancers combined will be presented, grouping the data by four-year period of death (the National Cancer Institute used five-year periods). The only three-year periods will include 1968-1970 (the earliest data available) and 2015-2017 (the most recent data available).

Methods and Materials
The rate of deaths per 100,000 persons (all ages), adjusted to the 2000 U.S. standard population, will be the measure of mortality employed in this review.
Age-adjustment is a long-employed statistical method used in epidemiology to facilitate true comparisons between groups, to avoid bias such as the highest mortality rates consistently occurring in areas heavily populated by the elderly.
Two sets of findings will be presented, namely 1) all-cause mortality, as radioactivity can harm various body systems, [8] and 2) all cancers combined, as the carcinogenic properties of radioactivity are well-recognized.
Mortality rate data will be accompanied by Salem County's rank in the state.
As New Jersey consists of 21 counties, a ranking of #1 signifies the highest rate in the state, while a ranking of #21 indicates the lowest rate in the state.
The test of whether differences in mortality rates between county and state are statistically significant will use 95% confidence intervals. All data on confidence intervals, age-adjusted death rates, number of deaths, and populations are automatically calculated with the Centers for Disease Control and Prevention data base. Table 2 and Figure 1       In each of the above categories, the Salem rate was the highest of any New Jersey county, except for white non-Hispanics (2 nd highest), black non-Hispanics (2 nd highest), and age 45 -64 (3 rd highest).The number of deaths among white Hispanics (18) and persons age 0 -24 (6) were too small to facilitate a significance analysis. Table 4 and Figure 2 present age-adjusted mortality for all causes combined for each four-year period from 1968 to 2017. From 1968From -1970From to 1983From -1986, the percent that the Salem County death rate exceeded the 20 other New Jersey counties dropped steadily, from +9.3% to +0.6%; the Salem County rate fell from the 3 rd highest to the 11 th highest rate (out of 21 county) in the state. After 1986, this trend reversed. A steady rise in the county vs. state excess occurred, until it reached a high of 28.4% in 2015-2017, the most recent period. In the last six periods, after 1994, Salem County's mortality rate has ranked 1 st , 2 nd , or 3 rd of New Jersey counties.

Discussion
The analysis of trends and current patterns of mortality in Salem County has revealed distinct patterns, both for all causes combined and for all cancers combined.
Through the late 1960s and continuing through all the 1970s to the mid-1980s, the county consistently showed all-cause death rates insignificantly above the rest of the state, which improved from +9.3% above to a low of +0.6% above in 1983-1986. The death rate for all cancers combined during this time also reached a low of −5.4% in 1983-1986. However, beginning in 1987, the all-cause mortality rate in the county, compared to the state steadily increased, as did the all-cancer mortality rate. Rates continue to rise, peaking in the most recent period of 2015-2017. Table 6 shows the percentages that Salem County rates exceed that of the other 20 New Jersey counties; it also calculated an "excess death" total for all causes and all cancers-calculated as the difference between the actual number of deaths minus the "expected" number, based on the presumption that 1983-1986 county/state ratio (+0.6% for all causes, −5.4% for all cancers) would not change.
The "excess" number of deaths among Salem County residents in the 31-year period 1987-2017 was 3493, of which 1018 were cancer deaths. These excesses  are about 16% of all county deaths for all causes, and 20% of all cancer deaths.
With county/state ratios having reached highs in the most recent period, it is very likely that excess deaths will increase in the future. The obvious issue raised in this report is that of etiology; that is, what factor(s) caused such a dramatic and unexpected rise in Salem death rates compared to the rest of the state. This question is not easily answered, as potential factors accounting for trends in death rates are multiple, and often cannot be identified.
Addressing the mortality trends of the past three decades in Salem County requires identification of potential causes that could not account for such trends. Commonly analyzed factors include changes in demographic makeup within the county, changes in access to medical care, and changes in living conditions. The fact that both cancer and all-cause mortality have increased simultaneously in Salem County suggests a potential common cause, and further may suggest a deterioration in the health care system, and health services performance indicators should be reviewed. Still, an excess deterioration in Salem County's system, compared to the state of New Jersey, would have to be demonstrated to support the health care system as a factor in the rising county/state mortality ratios.
A review of data shows no obvious differences in trends between Salem County and the rest of New Jersey. Similar demographic trends were experienced; Hispanic and black proportions of the population rose; male/female ratios and age-specific distribution remained essentially unchanged. No differences in trends in geographic access to medical care were obvious between county and state, nor were financial access to services. Finally, trends in living conditions (poverty, housing, food consumption, and unemployment) were similar to suggest that radioactive exposures could account for at least some of the gap between plant startup and mortality increases [9]. Findings interact with previous reviews, which have identified similar trends to those identified here. For example, one article focused on cancer incidence in Sacramento County, California USA, site of the Rancho Seco nuclear plant, which closed in 1989. The county/state ratio from the last two years of plant operation (1988)(1989) were compared with those of the following 20 years (1990-2009). The ratio after shutdown was consistently lower than before shutdown, leading to the estimate of 4319 fewer actual cancer cases versus expected, i.e., a continuation of the 1988-1989 ratio [10]. These similar findings lend greater credibility to the theory that Salem County increases in cancer mortality are due at least in part to continuing radioactive exposures from nuclear plant releases.
Exposure levels to nuclear plant emissions are impossible to calculate with precision. There are many separate radionuclides that are emitted; some have long half-lives while others decay rapidly; there is no steady emission pattern by time period; and the directions that gases and particles take once in the environment vary. Measuring levels of radioactivity in bodies of local residents would help, but only one known such study in the U.S. exists-an analysis of Strontium-90 in 5000 baby teeth [11]. Still, even relatively low doses of radiation exposure such as those of routine emissions from reactors, are known to cause damage to human health; a blue ribbon panel's most recent report reviewed hundreds of studies and concluded radiation takes a linear, no-threshold dose/response in health (no threshold meaning hazards exist even at very low doses [9]. A second follow up to this report is the dissemination of results among public elected and regulatory officials, who are mandated to maintain the safety of New Jersey residents, along with the public at large. The discovery of distinct trends that were previously unknown, more than three decades after they began, indicates that additional studies such as this should be conducted by officials. Finally, as Salem unit 1 has operated over 40 years, and Salem 2 will soon reach this milestone (the original legally-allowed period granted by government to operate), health patterns and trends should be a standard component in any public discussion and decision on the future of the Salem/Hope Creek plant.
Comparable efforts should be made near other operating nuclear plants. With 116 million Americans living within 50 miles from a nuclear power plant, the Salem situation should be seen as part of a national issue, not just a local one [12].